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Brief Review

History of Strength Training Research in Man: An Inventory and Quantitative Overview of Studies Published in English Between 1894 and 1979

Nuzzo, James L.

Author Information
Journal of Strength and Conditioning Research: May 2021 - Volume 35 - Issue 5 - p 1425-1448
doi: 10.1519/JSC.0000000000003959
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Abstract

“The principal value of studying history and thus learning how we got where we are is that it may enable us to isolate main currents which may give us some idea of where we are going.”

Dr. Philip J. Rasch, early strength training researcher (1960) (294)

Introduction

Strength training is physical exercise that involves repeated muscle contractions against external resistance or one's own body mass with the intent of improving muscle strength. When performed for several weeks, strength training can improve muscle size, strength, and endurance; cardiovascular risk factors; and performance on tasks associated with daily living and athletic performance (5,71,112,236,381). Consequently, strength training is part of exercise prescription guidelines for healthy and clinical populations (5,6,71,108,112,209).

Many years of experimentation were necessary to examine claims about the safety and effectiveness of strength training. Yet, few scholars conduct historical research on the early years of strength training experimentation. The existing scholarship, albeit rigorous and informative, is typically qualitative and biographical (329,360,361,364–366). Moreover, one of the main university textbooks on strength training does not discuss the history of strength training research (131) Historical competency is also not part of the American College of Sports Medicine's Knowledge, Skills, and Abilities for exercise science graduates.

In 2017, Kraemer et al. (185) made a significant contribution to the study of the history of strength training research. Among other achievements, the authors summarized influential researchers and thematic shifts in early strength training research. They also used network analysis to illustrate growth of strength training research, common research topics, and influential journals and articles. However, no quantitative descriptions of study characteristics (e.g., study samples, training programs, and study outcomes) were presented. Moreover, some important researchers (e.g., Phillip Rasch) and journals (e.g., Journal of the Association for Physical and Mental Rehabilitation) were not discussed (185). Thus, the study of early strength training research remains incomplete.

The current review had 2 aims. The first was to create an inventory of all strength training studies published before 1980. Inventories make article discovery more efficient, particularly for researchers who conduct historical reviews, systematic reviews, and meta-analyses. The second aim was to describe the characteristics of this early research quantitatively. Characteristics that were summarized included authors, journals, article citations, study type, study samples, study training programs, study outcomes, and general study themes. The importance of applying quantitative methods to the study of strength training history is that it provides objective information about early research and thus serves to reduce potential bias in historical interpretations.

Methods

Experimental Approach to the Problem

To provide a historical overview of early strength training studies, 3 general steps were taken, First, a search was performed to identify relevant articles. Second, after eligible articles were identified, data on publication information, study type and theme, study sample, study training intervention, and study outcome were extracted and organized in an electronic spreadsheet. Third, descriptive statistics were applied to the extracted information to describe the characteristics of the studies quantitatively.

Literature Search

Three general methods were used to identify early strength training studies. First, keyword searches were performed in PubMed, Google Scholar, and on journal/publisher websites for articles published before 1980. Example keywords included “isokinetic,” “isometric,” “isometric exercise,” “muscle training,” “progressive resistance exercise,” “resistance training,” “strength training,” “weight training,” and “weight lifting.” Second, searches were performed for authors who were known to have conducted strength training research before 1980. Author searches are simplified in PubMed and on journal/publisher websites because publications from a given author are usually linked to the author's name. Third, reference lists of eligible articles were screened for other articles that might be eligible for inclusion into the review.

Inclusion Criteria

Not all articles identified were eligible for inclusion into the review. First, articles needed to be published in English. This led to the exclusion of influential articles by Hettinger and Muller (147,148,257,258). Results from these articles have been summarized elsewhere (255,256). Second, articles needed to include human subjects. Third, articles needed to include a strength training intervention. Strength training was defined as an intervention ≥1 week in duration in which voluntary muscle contractions were performed against external resistance or one's body mass (e.g., sit-ups and push-ups) with the intent of improving muscle strength or other outcomes. This meant review articles without original data were excluded. This also meant articles in which strength training was not the primary focus of the training program could be included. This was deemed appropriate as the current review was concerned with the historical use of strength training in research rather than effect sizes of strength training interventions on outcomes. Nevertheless, most studies involved strength training as the sole intervention or primary focus of interventions. Finally, unpublished theses and dissertations were excluded.

Publication Information

The following data on publication information were extracted from each article: year of publication, decade of publication, journal of publication, number of authors, name of sole or first author, and number of citations per article. Author name was used solely, or in conjunction with other information about the author (e.g., headshot in article, biography, and obituary), to determine author sex. If an author's sex could not be determined, it was categorized as undetermined. Journal name was used to categorize each article into a general field of inquiry. General fields of inquiry were (a) rehabilitation and medicine (e.g., Archives of Physical Medicine and Rehabilitation), (b) exercise, fitness, sports, and physical education (e.g., Research Quarterly and Journal of Sports Medicine and Physical Fitness), (c) physiology (e.g., Journal of Applied Physiology), (d) human factors and ergonomics (e.g., Ergonomics), (e) gerontology (e.g., Journal of Gerontology), (f) nutrition (e.g., American Journal of Clinical Nutrition), (g) motor skills and behavior (e.g., Perceptual and Motor Skills), (h) psychology (e.g., Journal of Applied Psychology), and (i) others (e.g., Science). The number of times a article has been cited was determined using a Google Scholar search performed on July 28, 2020. Citation numbers were then used to identify the 10 most highly cited articles from this era and also to identify the most influential researchers.

Study Type and Topic

Articles were categorized as either case studies or experimental studies. Case studies were articles in which investigators delivered strength training programs to individuals and reported detailed individual results. Experimental studies were articles in which all individuals enrolled in a study group underwent the same intervention, with a focus on group results rather than individual results.

Articles were also categorized into general research themes based on the study's purpose and outcome measures. The general themes were (a) physical injury and rehabilitation, (b) physical fitness, (c) sports science, (d) physiology, (e) nutrition and supplementation, and (f) mental health. The physical injury and rehabilitation theme was defined as an examination of the impact of strength training on a physical health disorder. The physical fitness theme was defined an examination of the impact of strength training on field tests of physical fitness that were not sport-specific skills (e.g., one repetition maximum [1RM], sit-ups, vertical jump height, skinfolds, and step test). The sports science theme was liberally defined as an examination of the impact of strength training on a sports skill. This definition excluded studies that examined surrogate measures of sports performance (e.g., vertical jump height). The physiology theme was defined as an examination of the impact of strength training on laboratory-based measures of fitness and physiology (e.g., isometric or isokinetic strength and V̇o2 max). The nutrition and supplementation theme was defined as an examination of the impact of strength training plus diet or supplementation (i.e., protein and anabolic steroids) on health, fitness, or physiology. The mental health theme was defined as an examination of the impact of strength training on mental health outcomes or examination of the impact of strength training on health, fitness, or physiology in mental health patients.

Each article was typically categorized by the central theme of the article. For example, a study that examined the effects of anabolic steroids on 1RMs and limb girths was categorized under the nutrition and supplementation theme but not under the physical fitness theme. However, placement into multiple categories was deemed appropriate for some studies. For example, a study that examined the effect of strength training on neural drive in patients with motor impairments was categorized under physiology (i.e., neural drive outcome) and physical injury and rehabilitation (i.e., motor impairment patients).

Specific study topics were also noted and summarized. These topics included (a) training mode—circuit training, (b) training mode—skill training plus overload, (c) training volume or load, (d) training specificity—effect of training posture, (e) training specificity—effect of contraction type, (f) training specificity—effect of contraction speed, (g) supplementation—anabolic steroids, (h) supplementation—protein, (i) adaptations to training—“muscle boundness,” (j) adaptations to training—“spot reduction,” (k) adaptations to training—neural, (l) adaptations to training—cross-education, and (m) adaptations to training—detraining and strength retention.

Study Samples

The continuous data on study samples extracted from each article included: total sample size, sample size that underwent strength training, number of male subjects, number of female subjects, mean age, minimum age, and maximum age. Categorical data included sex category (male-only sample, female-only sample, mixed-sex sample, and sex not reported), age category (youth <18 years old, adult 18–65 years old, older adult >65 years old, and age not reported), health status category (healthy; neuromuscular, musculoskeletal, or pain conditions; psychological conditions; cardiac conditions; and overweight/obese), general demographic category (athlete, military personnel, prisoner, university student, general population, and not reported), and previous strength training experience category (yes, no, and not reported).

Study Training Interventions

Continuous data on study training interventions extracted from each article included the number of training days. Categorical data included general intervention type (strength training only, strength training plus other exercises, strength training plus diet or supplementation, strength training plus immobilization, and strength training plus other intervention), training muscle contraction type (isometric only, isoinertial only, isometric plus isoinertial, isokinetic only, concentric only, eccentric only, other, and not reported), target muscle group (upper-body and lower-body muscles, upper-body muscles only;, lower-body muscles only, and trunk muscles only), intervention duration (1, 2, 3 weeks…20 wk, and >20 wk), and intervention frequency (1 day per week, 2 days per week,…7 days per week, and not reported). For studies that involved training of only one muscle group, the muscle group was identified (e.g., elbow flexors).

Study Outcomes and Data Reporting

Information on study outcomes were also extracted from each article. Study outcomes were categorized by general fitness or physiology characteristic and were further categorized by the specific test used to assess this characteristic. General fitness or physiology characteristics included muscle strength, muscle endurance, power, motor/sensory skills, cardiovascular outcomes, muscle or body composition, neural outcomes, flexibility, injuries, and psychological outcomes. Tests of muscle strength that were tabulated included the 1RM (by muscle group), 5RMs (by muscle group), 10RMs (by muscle group), isometric maximal voluntary contractions (MVCs) (by muscle group), isokinetic strength (by muscle group), isoinertial dynamic torque (by muscle group), and training volume or work. The number of articles that reported multiple measures of muscle strength was also tabulated. This analysis was conducted because some contemporary researchers have expressed concerns that many strength training studies report changes in muscle strength only for the exercise and posture used during training (52,270).

Tests of muscle endurance that were tabulated included pull-ups, dips, sit-ups, push-ups, absolute load to failure, and hold endurance time. Tests of “power” that were tabulated included vertical jump height, broad jump distance, sprint time (run or swim), throwing velocity, and throwing distance. Tests of motor/sensory skills that were tabulated included balance tests, reaction time, throwing accuracy, finger dexterity, and others. Tests of cardiovascular health that were tabulated included 300-yd shuttle run time, step test, V̇o2 tests, and others. Tests of muscle or body composition that were tabulated included limb girths, lean body mass, muscle thickness or cross-sectional area, and muscle biopsy measures. Tests of nervous system function that were tabulated included neural drive (i.e., electromyography [EMG]), reflexes, and muscle twitches. Tests of flexibility that were tabulated included the sit-and-reach test and other tests of joint range of motion (ROM). Tests of injuries that were tabulated included future injury incidence and clinical symptoms. Tests of mental health outcomes were not subdivided into specific categories. Finally, information on the way investigators reported their data (i.e., individual data, mean values, or both) was also extracted from each article.

Statistical Analyses

SPSS version 25 (IBM, Armonk) was used to generate frequencies for categorical variables and descriptive statistics for continuous data. Descriptive statistics included means, SDs, sums, minimums, and maximums.

Results

Publication Information

Year

Three hundred thirty-nine strength training studies were published between 1894 and 1979 (1–4,7–19,22–45) (47–50,53–70,72–78) (80,82–92,94–107,110,111) (113–130,132–138,140–146) (149,150,152–157,159–170) (173–179,182,183,186–206,208) (210–233,235,237–244) (246–254,259–267) (271–280,282–288,295) (298–319,321–328) (330–359) (367–379,382) (383,385–394,396–399) (Figure 1). Three articles (0.9%) were published before 1940, 14 (4.1%) were published in the 1940s, 52 (15.3%) in the 1950s, 142 (41.9%) in the 1960s, and 128 (37.8%) in the 1970s.

Figure 1.
Figure 1.:
Number of strength training intervention studies by year from 1894 to 1979.

Journals

Sixty-six journals published at least one strength training article. Table 1 lists frequencies of articles in each journal. Research Quarterly published the most articles (27.4%). The number and percentages of articles published in journals from particular fields were as follows: rehabilitation and medicine (130; 38.3%); exercise, fitness, sports, and physical education (133; 39.2%); physiology (38; 11.2%); human factors and ergonomics (8; 2.4%); gerontology (5; 1.5%); nutrition (2; 0.6%); motor skills and behavior (10; 2.9%); psychology (3; 0.9%); and other (9; 2.7%).

Table 1 - Frequencies of strength training studies published in each journal.*
Journal name No. of studies % of total Reference
Acta Physiol Scand 4 1.2 (42,357–359)
Am Corr Ther J 18 5.3 (8,22,33,34,37,41,49,60,74,115,117,164,233,262,326,331,339,387)
Am J Clin Nutr 2 0.6 (301,367)
Am J Phys Med 6 1.8 (98,143,254,304,335,373)
Am J Physiol 2 0.6 (221,251)
Ann Phys Med 3 0.9 (64,84,342)
Arch Phys Med Rehabil 32 9.4 (12,13,88,89,91–94,120–122,142,187,189,190,202,203,218,220,235,239,249,295,314,315,322,327,338,345,351,355,374,399)
Br J Phys Med 2 0.6 (298,398)
Br J Sports Med 2 0.6 (18,394)
Ergonomics 5 1.5 (1,182,300,328,382)
Eur J Appl Physiol Occup Physiol 4 1.2 (102,183,188,284)
Int Z Angew Physiol 9 2.7 (43,134–136,159,231,288,302,305)
J Am Geriatr Soc 2 0.6 (173,244)
J Am Phys Ther Assoc 3 0.9 (149,276,283)
J Appl Physiol 10 2.9 (44,132,153,157,217,299,307,332,347,370)
J Appl Physiol Respir Environ Exerc Physiol 4 1.2 (76,101,125,127)
J Appl Psychol 2 0.6 (110,377)
J Assoc Phys Ment Rehabil 18 5.3 (36,59,99,124,130,174–179,198,199,211,311,356,379,385)
J Bone Joint Surg 4 1.2 (90,95,118,197)
J Gerontol 2 0.6 (65,68)
J Health Phys Educ Recr 2 0.6 (24,260)
J Mot Behav 2 0.6 (208,215)
J Physiol 2 0.6 (85,319)
J Sports Med Phys Fitness 11 3.2 (14,62,73,144,213,237,267,274,308,309,341)
JAMA 3 0.9 (240,312,371)
Lancet 2 0.6 (145,318)
Med Sci Sports 20 6.1 (9–11,50,107,113,123,163,165,167,201,216,252,285,310,325,348,375,388,389)
Percept Mot Skills 8 2.4 (154,210,212,241,282,303,336,396)
Phys Ther 7 2.1 (82,150,160,222,246,247)
Phys Ther Rev 9 2.7 (140,141,155,193–195,275,280,378)
Physiotherapy 2 0.6 (253,316)
Res Q 93 27.4 (3,4,15–17,19,23,25–32) (35,39,40,45,48,53–58) (66,67,70,72,75,78,96,97,100,111,119,133,137,138,146,156,162,166,170,186,191,192,196,205) (219,223–230,232,238,242,248,250) (259,263,266,271–273,277–279,286) (287,306,321,323,330,333,334,346,349) (352,368,369,372,376,383,386,392,393,397)
Scand J Clin Lab Invest 2 0.6 (128,214)
Scand J Rehabil Med 6 1.8 (87,116,129,161,206,261)
Scand J Rheumatol 4 1.2 (103,104,264,265)
South Med J 2 0.6 (313,390)
*Journals that published 1 strength training study were Acta Orthopaedica Scandinavica (47), Acta Paediatr Scand (105), Am J Phys Anthropol (353), Am J Sports Med (106), Am Phys Educ Rev (7), Am Pract Dig Treat (317), Aust J Physiother (340), Aviat Space Environ Med (126), BMJ (114), Bull Br Assoc Sport Med (343), Bull NY Acad Med (344), Electroencephalogr Clin Neurophysiol (243), Electromyography (63), Hum Biol (61), Hum Factors (337), Int J Aging Hum Develop (204), J Clin Invest (69), J Neurol Neurosurg Psychiatr (200), J Phys Educ Recr (354), Jap J Rehabil Med (2), Medical Arts and Sciences (83), Metabolism (38), Physical Educator (86), Physician and Sportsmedicine (77), Physiother Rev (169), Proc Hum Factors Soc Ann Meet (152), Psychol Rev (391), Rheumatol Rehabil (80), Science (168), and Studies from Yale Psychol Lab (324).
Some journals changed names throughout the era examined. Name changes were: Journal of the Association for Physical and Mental Rehabilitation (1947–1967) changed to American Corrective Therapy Journal (1967–1987), Bulletin—British Association of Sport and Medicine (1964–1968) changed to British Journal of Sports Medicine (1969-present), Internationale Zeitschrift für angewandte Physiologie, einschliesslich Arbeitsphysiologie (1955–1973) changed to European Journal of Applied Physiology and Occupational Physiology (1973–1999), Journal of Applied Physiology (1948–1976) changed to Journal of Applied Physiology: Respiratory, Environmental and Exercise Physiology (1977–1984), Physiotherapy Review (1926–1948) changed to Physical Therapy Review (1948–1961) then to Journal of the American Physical Therapy Association (1962–1963) then to Physical Therapy (1964-present), and Annals of Physical Medicine (1952–1970) changed to Rheumatology and Physical Medicine (1970–1972) then to Rheumatology and Rehabilitation (1973–1982).

Authors

One hundred fifty-one articles (44.5%) were authored by one investigator, 95 (28.0%) by 2 investigators, 40 (11.8%) by 3 investigators, 37 (10.9%) by 4 investigators, 10 (3.0%) by 5 investigators, and 6 (1.8%) by ≥6 investigators. The mean number of authors per article was 2.1 ± 1.3 (range: 1–9). Men were sole or first author on 276 articles (81.4%). Women were sole or first author on 37 articles (10.9%). For 26 articles (7.7%), sex of the sole or first author could not be determined. Table 2 lists researchers who were sole or first authors on the greatest number of articles.

Table 2 - Researchers who were first or sole author on the greatest number of strength training studies between 1894 and 1979.*
Author No. of articles Total citations Study topics References
Richard Berger 12 1,293 ST loads and volumes on muscle strength (25–36)
Philip Rasch 9 318 ST specificity, ST for mental health, and ST with protein (295,298–305)
Karl Klein 6 5 ST for recovery from knee injury (174–179)
Thomas DeLorme 5 772 Progressive resistance exercise for rehabilitation (90–92,94,95)
Leon Smith 5 62 ST on movement speed and cross-education (334–339)
Edward Capen 4 237 ST prescriptions for physical fitness (56–59)
Frances Hellebrandt 4 402 Cross-education, neural adaptations, and ST load and pacing (140–143)
George McGlynn 4 35 ST on muscle strength and endurance and their relation (230–233)
Larry Shaver 4 102 Cross-education and de-training (325–328)
*ST = strength training.
Number of citations obtained from Google Scholar search on July 28, 2020.

Citations

Citation numbers were acquired for all but 2 articles. The total number of citations was 21,996. The mean number of citations per article was 65.3 ± 135.7 (range: 0–1,815). Table 3 lists the 10 most frequently cited articles and their authors. Seven of the 10 most frequently cited articles were published in the 1970s.

Table 3 - Ten most frequently cited strength training studies published between 1894 and 1979.
Author (ref) Journal Year Title Citations*
Moritani and deVries (254) Am J Phys Med 1979 Neural factors vs. hypertrophy in the time course of muscle strength gain 1,815
DeLorme (90) J Bone Joint Surg 1945 Restoration of muscle power by heavy resistance exercises 628
Milner-Brown et al. (243) Electroencephalogr Clin Neurophysiol 1975 Synchronization of human motor units: possible role of exercise and supraspinal reflexes 560
Komi and Buskirk (182) Ergonomics 1972 Effect of eccentric and concentric muscle conditioning of tension and electrical activity of human muscle 558
Costill et al. (76) J Appl Physiol Respir Environ Exerc Physiol 1979 Adaptations in skeletal muscle after strength training 500
Wilmore (388) Med Sci Sports 1974 Alterations in strength, body composition, and anthropometric measurements consequent to a 10-wk weight-training program 442
Berger (27) Res Q 1962 Effect of varied weight-training programs on strength 423
MacDougall et al. (217) J Appl Physiol 1977 Biochemical adaptation of human skeletal muscle to heavy resistance training and immobilization 417
Moffroid et al. (246) Phys Ther 1969 A study of isokinetic exercise 410
Bjorntrop et al. (38) Metabolism 1970 The effect of physical training on insulin production in obesity 376
*Number of citations of article obtained from Google Scholar search on July 28, 2020.

Study Type and Topic

Of the 339 articles, 306 (90.3%) were experimental, 31 (9.1%) were case studies, and 2 (0.06%) contained both experimental and case studies. Of the 31 case studies, 6 (19.3%) were published in the 1940s, 14 (35.9%) in the 1950s, 10 (25.6%) in the 1960s, and 3 (7.7%) in the 1970s. Table 4 provides frequencies of the research topics examined by early investigators. The most common research theme was physiology (54.3%).

Table 4 - Selection of topics addressed in early strength training studies.
Topics No. of articles % of articles References
General theme
 Physiology 184 54.3 (2,4,7,9,12,13,22,23,37,38,42–45) (47,53,60,63–65,67–70,72,73,75,76,78,80) (82,84,85,88,89,92,98,101,102,104,106,110,113,115–117) (119–121,125–129,133–137) (140–143,146,149,150,153,155,157,159) (161,164–166,170,182,183,186–189,196,197) (200–204,206,208,210,214–219,221,222,225,226) (229–233,239,241–243,246,247,249–251,254,259,264,265)
(273,275–280,282,283,287,288,295) (299–310,313,314,319,324–328,330–338,340) (344,345,347,349–352,355,357–359) (367,370,372–374,377,378,382,383,386,387,391,397)
 Physical fitness 98 28.9 (1,9,10,14–19,24–33,35–37,39–41) (44,45,47,48,50,54–59,61,62,66,68,74,96,97,99,100) (107,114–117,122,123,152,154,156,163–165) (167,168,170,173,188,191,192,198,199,205,213,223,224) (227,228,237,238,244,248,260,262,263,267,271,272) (274,277,284,285,309,321–323,341,348,353,354) (368,369,375,376,379,385,388,389,392–394,396)
 Physical injury, rehabilitation 70 20.6 (24,41,69,77,80,83,87,90,91,94,95,103–106) (111,115,116,118,121,124,130,132,137,138,150,160) (161,169,173–178,190,193–195,200) (203,214,217,218,220,235,240,253,261,264,265,275) (276,312–318,322,342,344,345,371,390,398,399)
 Sports science 17 5.0 (3,8,34,48,55,86,100,144,162,211,212,266,286,343,346,356,394)
 Nutrition and supplementation 17 5.0 (9–11,61,62,107,114,145,167,168,213,248,301,341,348,367,375)
 Mental health 9 2.7 (22,41,49,68,222,252,260,298,339)
Specific topic
 Training mode
  Circuit training 16 4.7 (1,4,17,68,117,122,123,156,227,252,253,260,266,267,309,389)
  Skill training + overload 5 1.5 (48,211,212,286,346)
 Training volume or load 44 13.0 (13,17,19,25,27–33,35,36,42,57,58,78,88,89) (102,124,140,141,149,189,190,199,225,235,242,250,259) (271,272,287,288,308,319,349,351,370,373,385,392)
 Training specificity
  Effect of training posture 15 4.4 (23,37,119,120,146,206,210,239,242,299,304,305,310,331,382)
  Effect of contraction type 55 16.2 (2,13,15,18,23,26,30,31,33,42,43,47,67,72,73,77) (85,88,97,102,120,121,132,134,135,138,141,163,165,182) (196,203,222,229,237,246,262,263,277,285,299,300,303) (319,332,334–337,351,373,374,382)
  Effect of contraction speed 7 2.1 (13,36,67,92,141,247,369)
 Supplementation
  Anabolic steroids 13 3.8 (9–11,62,107,114,145,167,168,213,341,348,375)
  Protein 2 0.6 (301,367)
 Adaptations to training
  “Spot reduction” 8 2.4 (61,161,188,227,241,248,273,321)
  “Muscle boundness”* 15 4.4 (54,56,66,67,70,75,86,92,120,198,219,223,224,356,386)
  Neural 55 16.2 (7,11,12,22,45,63,64,85,95,98,113,115,134,136) (140,142,143,149,150,153–155,157,159) (182,186–188,201,203,221,243,254,275) (276,279,295,299,306,313,314,325,327,332) (335,336,340,343,345,359,373,374,378,391)
  Cross-education 48 14.2 (13,22,42,45,47,72,85,119,142,143,152,153,159) (175,183,186–189,197,203,206,218,220,226,239,242,254,273,276) (295,299,313,314,324,325,327,328,333,335,336,340,373,378,391,399)
  Detraining and retention 36 10.6 (32,80,85,101,106,125–127,132,146,149,150,155,161,177,217,239,250,280,287,288,311,314,323,326–328,333,342,347,352,353,357,372–374)
*Articles in which “muscle boundness” was investigated or was discussed in relation to the hypothesis or result.
Articles in which measures of the nervous system were acquired or changes in the nervous system were discussed in relation to the hypothesis or result.

Study Samples

Three hundred thirty-six articles (99.1%) reported the sample size. Studies included a total of 14,575 subjects. A total of 10, 201 were men (70.0%), 1,704 were women (11.7%), and sex was unknown for the remaining 2,670 (18.1%). A total of 10,350 subjects underwent strength training. The mean sample size for strength training groups was 32.9 ± 37.9. Subjects' age ranged from 6 to 88 years. The mean age was 27.1 ± 14.0 years; however, this figure was computed only from those articles in which the mean age was reported (80 articles, 23.6%). Table 5 provides frequencies of categorical data on study samples.

Table 5 - Frequencies of categorical data on study samples from early strength training studies.*
Variable No. of articles % of articles References
Sex category
 Male only 203 59.9 (3,4,7,9–11,13,16–19,23–28,30–37) (39–41,45,48,49,53–55,57,58,62–65) (67,69,72–77,86,88,89,92,96,99–102,107) (113,114,116–118,120,122,123,125–128) (132,133,138,144–146,149,150,159,161–163) (165–170,175,178,182,186,191,192,194,195,197,198) (201,202,204,205,208,211–219,221,223–226,228) (229,237,238,240,242,244,250–253,260,262,263,266,267,273) (278,279,283–288,295,298–308,310) (315,323,325–328,331–338,340–342) (346–349,352,353,356–359,367,368,370,372) (374–377,382,383,385–387,391–394,397,399)
 Female only 34 10.0 (43,47,50,59,61,87,111,129,134–137,141,142,153,155,157,187,188,206,210,227,241,248,274,277,309,321,324,343,354,369,379,396)
 Male and female 53 15.6 (2,12,13,22,38,42,68,78,80,84,103,105) (115,121,140,143,152,154,160,164,183,190,193,200,220,235,239) (246,247,249,254,264,265,275,276,280,312,313,316) (318,319,322,344,345,350,351,371,373,378,388–390)
 Not reported 46 13.6 (1,8,14,29,44,56,60,66,83,85,90,91,94,95,97) (98,104,106,119,124,156,173,174,176,177,179,196,199) (203,222,230–233,243,259,261) (271,272,282,310,311,314,339,355,398)
Age category
 Youth (<18 yr) 34 10.0 (8,17,22,41,44,49,54,65,78,92,102,105,118,138,144,146,183,191,200,205,214,240,273,276,287,288,316,318,346,371,376,379,393)
 Adult (18–65 yr) 294 86.7 (1–4,7,9–16,18,19,23–45,47,48) (50,53,55–64,66,67,69,70,72–77,80,82) (84–91,94–101,103,104,106,107,110) (111,113–117,119–130) (132–137,140–143,145,149,150,152–157) (159–170,173–179,182) (186–190,192–204,206,208) (210–213,215–233,235) (237–244,246–254,259–267,271,272,274)
(275,276,278,279,282–286,295,298–310) (312–314,316–319,321–328,330–345) (347–359,367–375,377,378,382,383) (385–392,394,396–399)
 Older adult (>65 yr) 15 4.4 (65,68,115,130,173,200,204,218,220,280,311,315,316,322,344)
 Not reported 15 4.4 (83,85,90,91,94,119,124,198,202,243,260,298,324,355,398)
Health status category
 Healthy 275 81.1 (1–4,7–19,23,25–37,39,40) (42–45,47,48,50,53–67) (70,72–76,78,80,82,84–86,88,89,92,97–102) (107,110,111,113–115,117,119,120) (122–130,132–136,140–146,149,150,152–157,159) (162–168,170,182,183,186–189,191,192,196,198–206) (208,210–213,215–217,219–221,223–233,235,237–239) (241–244,246–252,254,259,262,263,266,267,271–274) (277–280,282–285)
(286–288,295,299–310,313,314,316,319) (323–328,330–338,340,341) (343–359,367–370) (372–379,382,383,385–389,391–394,396,397)
 NM, MSK, and pain conditions 66 19.5 (24,41,69,77,83,84,87,88,90,91,94,95,103–106) (111,115,116,118,121,124,130,137,138,160,161,169,174–179) (190,193–195,197,200,203,214,218,220,235,240) (261,264,265,275,276,312–318,322,342,344,345,371,390,398,399)
 Psychological conditions 9 2.7 (22,41,49,68,222,260,298,316,339)
 Cardiac conditions 4 1.2 (41,173,253,311)
 Overweight/obese 3 0.9 (38,96,321)
Previous ST experience
 Yes 9 2.7 (9–11,50,104,107,375)
 No 27 8.0 (4,33,35,56,66,97,114,117,128,129,149,150,157,196,217,221,223,224,250,273,307,323,341,357–359,369,386)
 Not reported 303 89.4
General demographic category
 Athlete 23 6.8 (3,7–11,48,50,55,114,144,161,212,213,238,249,274,307,312,343,356,369,394)
 Military 9 2.7 (24,95,169,194,195,197,222,317,399)
 Prisoner 4 1.2 (251,335,336,341)
 General population 120 35.4 (2,12,13,17,22,38,40–42,44,47,49,53,54,60) (65,68,76–78,80,84,87–89,92,96,101–106) (111,116,118,121–127,130,132,134–136) (138,140–142,146,149,150,152,155,160) (173,176,178,183,190,191,193,200,203–205) (214,216,218,220,235,240,246,247,249,252,253,260,261) (264,265,273,275–277,280,284,285,287,288,298) (311–319,322,339,341,342,344–347) (371,376,377,379,390,393,397)
 University student 173 51.0 (1,4,14–16,18,19,23,25–37,39,43,45) (56–59,61,63,64,66,67,70,72–75) (82,86,97–100,107,111,113,115,117,120) (128,129,133,137,143,145,153,154,156,157,159,162–167,170) (174,175,177,179,182,187–189,192,196,199) (206,208,210,211,213,215,217,219–221) (223–233,241,242,244,248,250,259,262,263,266,267,271,272) (278,279,282,283,286,295,299–310,312,321,323,325–328) (330–334,337,338,340,345,348–354,357–359) (367,368,370,372–375,378,382,383,385–389,392,396)
 PE, PT, NS, and MD students 41 12.1 (28,43,47,59,63,64,115,129,134–136) (143,145,153,157,164,196,217,219,242,279,282,283) (295,299–305,344,345,348,351) (357–359,373,378,397)
 ST delivered in PE class 65 19.2 (14,17–19,27,28,30–32,34,35,56,66,67) (70,72–75,78,97–100,102,113,117,133,137) (154,162,163,167,170,192,199,205,223,224,227–229) (260,262,263,266,267,271–273,277,286,309,323,334) (338,340,354,372,382,383,386–388,392)
Not reported 21 6.2 (62,83,85,90,91,94,110,119,186,198,201,237,239,243,254,267,324,355,391,398)
*MD = medical; MSK = musculoskeletal; NM = neuromuscular; NS = nursing; PE = physical education; ST = strength training.
Subcategories add to >100% because some studies included subjects from multiple subcategories.
40 (64.5%) were published in Research Quarterly.

Study Training Interventions

Experimental studies included 549 groups that underwent strength training and 172 groups that did not undergo strength training. The mean number of strength training groups per study was 1.8 ± 1.4 (range: 1–10). Table 6 displays frequencies of categorical data pertaining to training intervention characteristics. Figure 2 depicts the number of studies with interventions of specified durations. Interventions were typically 4–8 weeks (55.3%). Figure 3 depicts the number of studies with interventions of specified training frequencies. Interventions typically involved 3 training days per week (39.2%). The mean number of scheduled training days—i.e., weeks of training scheduled multiplied by the number of training sessions scheduled per week—was 27.5 ± 18.5 per study (range: 7–145 days).

Table 6 - Frequencies of categorical data on interventions from early strength training studies.*
Variable No. of articles % of articles References
Intervention
 ST only 270 79.6 (1–4,7,8,12–16,19,22,23,25–33) (35–37,39,40,42,43,45,47,48,53–59,62–67,70) (72–78,80,82–90,92,94,95,97,98,102–104) (106,110,111,113–124,128,129,133–135,137,138) (140–144,146,149,150,152–157,159,160,162,163,165) (166,169,170,174–179,182,183,186–199,201–206) (208,210–212,215,216,218–220,222–233,235,237,239) (241–244,246–254,259,262,263,271–275) (277,278,280,282–285) (286-288,295,298–300,302–306) (308–310,312–319,322–328) (330–342,344,345,349–353) (355,369–374,376–378,382,383,385) (386,388–394,396–399)
 ST + other exercises 38 11.2 (17,24,34,38,41,44,68,77,80,82,96,99,100,105,130,162,164,213,214,238,260,261,264–267,279,286,307,323,346,356–359,368,379,387)
 ST + diet or anabolic steroids 18 5.3 (9–11,61,62,69,107,114,145,167,168,213,301,321,341,348,367,375)
 ST + immobilization 9 2.7 (101,125–127,132,150,161,217,347)
 ST + other interventions 5 1.5 (106,133,157,166,221)
ST contraction type
 Isometric only 120 35.4 (3,7,12–15,23,24,26,27,30,31,37,42) (45,47,49,53,60,63,64,67,72,73,78,80,82,84,85,88) (97,101,106,110,115,119–121,125–129) (132–135,138,146,149,150,152,166,173,183,186,187) (195–197,199,200,202–206,208,210,215) (218–220,225,229–233,237,242) (248–250,262,263,277,278,280,283,285,287,288,295,299) (302,304,305,308,311,319,322,324,335,336,339) (343–345,347,355,367,370,373,374,377,382,393,397,399)
 Isoinertial only 219 64.6 (1,2,4,8–11,13,16–19,22,23,25–32) (34–36,40,41,43,44,47,48,50,54,56–59,61) (62,65–70,74,75,77,83,86,88–92,94,95) (97–100,102–105,107,111,113,114,117,118,120,121,123,124) (136–138,140–142,145,153–157,159–161,164) (167–170,174–179,190–195,197–199) (203,211–214,216,217,219–221,223,225–227,229) (235,237–240,244,251–254,259–267,271–278,280) (282,284,298–301,303,307,310,312–319,321,323,325) (328,330,331,333,335–337,340–342,346) (348–350,353–359,368,371,373–376) (378,379,382,383,385–392,394,398,399)
 Isometric + isoinertial 19 5.6 (8,18,38,87,96,130,143,162,228,237,279,286,306,309,334,338,351,383,396)
 Isokinetic only 11 3.2 (39,76,116,122,188,201,246,247,285,355,369)
 Concentric only 7 2.1 (37,85,163,165,182,222,241)
 Eccentric only 9 2.7 (2,37,42,163,165,182,196,222,332)
 Other 7 2.1 (42,45,144,189,326,327,352)
 Not reported 4 1.2 (44,243,307,308)
Target muscle group
 Upper-body and lower-body muscles 107 31.6 (1,2,4,9,10,14,17,38,40–42,49,50,55,56) (58–62,66–68,70,74,84,91,92,107,114,117) (119–123,142,145,155,156,162–165) (167–169,173,191,198,199,204,213,214,224) (227–229,238,240,244,252,253,259,260,262,263) (266,267,271,275,276,284,285,298,307,311,321) (323,338,341,348,353,354,357–359,367,368,371,374,375) (379,385,386,388–390,392–394,397)
 Upper-body only 120 35.4
  Upper-body multiple muscles 35 10.3 (3,18,25,27–30,33–36,54,105,140,143,166,179,187,200,223,261,273,277,282,299–301,303,331,334,337,351,356)
 Upper-body single muscles 85 25.1
  Grip only 9 2.7 (7,53,110,215,295,324,337,370,377)
  Elbow flexors only 42 12.4 (22,43,45,72,73,78,85,133–136) (146,149,150,152,157,159,182,189,208,210,219,225) (226,242,250,254,283,302,304,325–328) (333,340,349,350,352,372,373,391)
  Elbow extensors only 8 2.4 (37,129,216,217,222,239,305,332)
  Shoulder only 8 2.4 (48,75,211,212,286,346,382,383)
  Pronators or supinators only 2 0.6 (141,319)
  Wrist flexors only 9 2.7 (13,23,186,231–233,249,287,288)
  Finger muscles only 8 2.4 (47,65,202,203,221,230,243,322)
 Lower-body only 93 27.4
  Lower-body multiple muscles 27 8.0 (15,16,24,31,32,39,69,95,100,102,113,118,144,154,178,201,205,264,265,272,280,306,342,343,369,387,396)
  Lower-body single muscles 66 19.5
  Knee extensors only 61 18.0 (12,19,76,77,80,82,83,88–90) (103,104,106,115,124–128,130,132,138,153) (160,161,174–177,183,188,190,193–197) (206,218,235,237,241,247,251,264,265,278,279) (312–317,344,345,347,355,398,399)
  Knee flexors only 2 0.6 (310,378)
  Hip only 3 0.9 (94,220,310)
  Ankle plantar flexors only 1 0.3 (116)
 Trunk only 9 2.7
  Extensors + flexors 1 0.3 (111)
  Extensors only (low back) 3 0.9 (26,63,64)
  Flexors only (abdominals) 5 1.5 (57,137,170,248,376)
 Not reported 8 2.4 (8,11,44,96–98,192,309)
*ST = strength training.
Subcategories add to >100% because some studies included subjects from multiple subcategories.
“Weight training” in articles was interpreted to mean isoinertial training with dumbbells, barbells, etc.

Figure 2.
Figure 2.:
Number of strength training intervention studies between 1894 and 1979 that included interventions of specified durations. Of the 339 studies, 18 (5.3%) did not report the duration. Also, 28 studies (8.3%) reported multiple durations, usually because multiple study groups performed interventions of different durations. These 28 studies are not represented in the figure.
Figure 3.
Figure 3.:
Number of strength training intervention studies between 1894 and 1979 that included interventions of specified frequencies. Of the 339 studies, 32 (9.4%) did not report the frequency of training and 13 (3.8%) reported multiple frequencies, usually because multiple study groups performed interventions of different frequencies. These 45 studies are not represented in the figure. NB. “Daily training” in articles was interpreted to mean 7 days per week, unless specified otherwise.

Study Outcomes and Data Reporting

Table 7 provides frequencies of categorical data on muscle strength assessments. Two hundred sixty-eight articles (79.1%) included results from at least one test of muscle strength. One hundred fifty-five articles (45.7%) included multiple measures of muscle strength. Seventy-one articles (20.9%) did not include results from tests of muscle strength. Table 8 provides frequencies of categorical data on outcomes other than muscle strength.

Table 7 - Frequencies of categorical data on strength tests in early strength training studies.*
Variable No. of articles % of articles References
Isokinetic tests 15 4.4
 Upper body 4 1.2 (107,122,123,285)
 Lower body 14 4.1 (76,77,87,107,116,122,123,201,206,246,247,285,355,369)
Isoinertial—1RM 69 20.4
 Upper body 46 13.6
  Bench press 30 8.8 (9,10,25,27,28,30,33,35,36,50,74,107,114,122,163,164,167,168,213,263,271,282,284,285,341,375,388,389,392)
  Shoulder press 10 2.9 (9,10,114,122,165,213,282,284,353,389)
  Biceps curl 20 5.9 (22,43,72,74,92,122,134–136,142,155,165,282,284,285,353,374,388,389,392)
  Other 7 2.1 (47,74,203,261,351,353,389)
 Lower body 44 13.0
  Squat 17 5.0 (9,10,32,50,102,114,167,168,213,271,272,353,357–359,375,392)
  Leg press 10 2.9 (69,74,118,122,213,263,284,312,313,389)
  Knee extension 19 5.6 (19,77,83,90–92,118,142,155,164,165,190,197,279,314,374,389,399)
  Deadlift 1 0.3 (107)
  Other 3 0.9 (92,164,165)
 Back or abdominals 3 0.9 (26,69,111)
Isoinertial—5RMs 4 1.2
 Knee extension 2 0.6 (2,190)
 Other 2 0.6 (73,260)
Isoinertial—10RMs 30 8.8
 Knee extension 22 6.5 (19,83,90,91,95,121,124,130,142,155,160,174,175,193,195,197,235,280,355,374,398,399)
 Other 6 1.8 (2,47,113,220,227)
Isometric MVC 183 54.0
 Upper body 128 37.8
  Bench or chest press 3 0.9 (229,263,308)
  Grip 30 8.8 (1,7,42,53–56,59,60,62,110,142,215,224,227,274,276,295,309,318,322,324,337,341,354,370,377,388,393,394)
  Elbow flexion 67 19.8 (38,42,43,45,58,62,67,72,78,84,98,103,104) (133–136,146,149,150,159,165,167,168,182,183,189,199,200) (204,208,210,213,219,225,226,242,250,254,264,265,273) (274,280,283,285,295,299,300,302–304,311) (318,319,325,326,328,331,332,339,340,348,373,374,385,394)
  Elbow extension 31 9.1 (3,8,37,58,67,98,121,129,142,165,168,187,199,204,216,217,239,273,274,285,300,303,305,311,318,331,332,339,340,394)
  Shoulder any 17 5.0 (3,49,58,67,70,75,84,165,167,168,179,274,299,334,338,382,383)
  Pronation or supination 2 0.6 (84,85)
  Wrist flexion 10 2.9 (3,13,23,186,231–233,249,287,288)
  Wrist extension 1 0.3 (3)
  Finger any 7 2.1 (47,65,202,203,230,243,322)
 Lower body 80 23.6
  Squat 1 0.3 (15)
  Leg press 4 1.2 (49,229,263,388)
  Back and leg dynamometer 11 3.2 (56,59,100,199,224,238,272,309,341,354,393)
  Knee extension 62 18.3 (12,16,24,38,42,45,58,62,67,80,82,87) (102–104,113,115,119,121,128,138,154,167,168) (174,176,177,183,188,196,201,204,206,213,218) (228,237,238,241,246,264,265,274,278,279,285,311) (318,335,336,339,342–345,357–359,374,378,394,398)
  Knee flexion 20 5.9 (24,58,62,103,104,121,165,174,177,204,228,238,246,310,311,318,339,342,378)
  Hip any 9 2.7 (16,67,228,238,274,310,336,342,343)
  Ankle plantar flexion 8 2.4 (16,116,238,274,306,342,343,396)
  Ankle dorsiflexion 4 1.2 (98,238,342,396)
 Trunk extension 17 5.0 (1,26,38,49,56,59,62–64,67,87,100,111,224,354,385,393)
 Trunk flexion 10 2.9 (38,49,62,67,87,100,111,137,376,385)
Dynamic torque 8 2.4
 Upper body 6 1.8 (37,85,182,222,332,391)
 Lower body 2 0.6 (103,104)
Training load, work, or volume 20 5.9 (4,115,140,141,143,155,157,178,179,195,240,253,271,300,301,315–317,371)
*1RM = one repetition maximum; MVC = maximal voluntary contraction.
Includes “back lift” performed on back and leg dynamometer.

Table 8 - Frequencies of categorical data on outcomes other than muscle strength in early strength training studies.*
Variable No. of articles % of articles References
Muscle endurance 66 19.5
 Pull-ups 14 4.1 (1,17,55,56,59,97,164,191,192,223,266,277,309,331)
 Dips 7 2.1 (1,17,56,97,164,223,266)
 Sit-ups 9 2.7 (41,55–57,59,164,170,192,376)
 Push-ups 5 1.5 (18,99,191,266,309)
 Absolute load to failure 25 7.4 (36,43,64,89,102,115,134–136,153,189,201,226,229,261,263,325–327,333,341,352,372,373,387)
 Hold endurance time 24 7.1 (13,14,53,88,102,134–137,152,183,203,208,215,230–233,242,263,337,344,345,370)
Power 53 15.6
 Vertical jump 22 6.5 (1,14–17,31,39,55,56,66,192,228,237,238,266,285,357–359,368,369,393)
 Broad jump 12 3.5 (56,59,66,99,191,205,238,285,323,357–359)
 Sprint 14 4.1 (14,66,86,100,144,162,238,266,271,285,323,343,368)
 Throwing velocity 18 5.3 (48,54,67,70,75,211,212,219,223,277,282,286,334,338,346,356,383,386)
 Throwing distance 4 1.2 (8,56,66,285)
Motor and sensory skills 22 6.5
 Balance 4 1.2 (68,132,394,396)
 Reaction time 5 1.5 (13,70,213)
 Throwing accuracy 5 1.5 (34,48,54,286,346,350)
 Finger dexterity 1 0.3 (54)
 Other 8 2.4 (68,103,104,126,160,223,264,371)
Cardiovascular 57 16.8
 300-yd shuttle run 4 1.2 (55,56,99,368)
 Step test 8 2.4 (1,17,41,44,117,156,191,309)
 V̇o 2 test 29 8.6 (4,38,77,78,101,103–105,107,113,122,123,125–127,167,168,213,214,259,261,264,265,271,307,347,348,389,394)
 Other 35 10.3 (4,14,38,44,53,60,68,101,103–105,114,117,122,125–128,152,162,173,213,214,251,253,259,261,267,307,330,347,370,387,389,397)
Muscle and body composition 97 28.6
 Muscle CSA and thickness 4 1.2 (102,159,188,254)
 Muscle biopsy measure 18 5.3 (76,77,102,106,116,128,183,188,216,217,251,264,265,278,279,357–359)
 Lean body mass 17 5.0 (40,74,96,107,122,123,125,145,161,227,284,357–359,375,388,389)
 Skinfolds or BF% 28 8.3 (40,50,59–61,74,96,107,114,122,125,145,161,227,242,244,248,273,274,284,285,307,367,374,375,379,388,389,394)
 Limb girths 71 20.9 (14,19,22,40,45,50,54,59,60,74) (90–92,95,96,98,107,115,122,145,149,150,154,161) (167,168,182,183,191,197,199,201,203,213,217,224) (227,239,241,242,244,248,262,272–274,284) (285,299–304,313,314,321,341,344,345) (348,353,357–359,367,374,388,394,398,399)
Neural 27 8.0
 Neural drive (EMG) 22 6.5 (22,45,60,63,64,98,121,140,154,182,183,200,208,243,254,275,276,332,344,345,359,391)
 Reflexes 3 0.9 (11,12,113)
 Muscle twitch 2 0.6 (12,203)
Flexibility, joint ROM 19 5.6
 Sit-and-reach 2 0.6 (191,389)
 Other 19 5.6 (41,65,90,91,95,100,120,130,138,191,198,199,202,224,238,310,322,385,389)
Injuries
 Future injury incidence 1 0.3 (24)
 Clinical symptoms 23 6.8 (69,90,91,94,95,103,104,111,137,169,173,194,195,200,253,261,275,312,317,342,371,398)
Psychological outcome 13 3.8 (41,49,68,87,103,104,252,264,265,298,313,339,394)
*BF = body fat; CSA = cross-sectional area EMG = electromyographic activity; ROM = range of motion.
Some measures of muscle activity were supplemental to the study purpose and not measured before and after the intervention.
Muscle twitches are classified under “neural” because they involve electrical stimulation of peripheral nerves; however, changes in muscle twitch forces after training are typically believed to represent anatomical and/or physiological adaptations of the muscle not the nervous system.

Group means for study outcomes were reported in 283 (83.5%) articles. Individual data were reported in 67 articles (19.8%). Fourteen articles (4.1%) included a comment on adverse events (15,39,62,85,87,114,155,168,191,193,218,253,283,341).

Discussion

The purpose of the current review was to create an inventory of all strength training studies published before 1980 and to describe them quantitatively. The results add to the limited but growing body of scholarship on the history of strength training research (185). The following discussion uses these quantitative results to describe the history of strength training research. A timeline and summary of research from this era is provided in Table 9.

Table 9 - Summary and timeline of notable themes, researchers, and journals associated with early strength training studies.*
Decade Research themes Notable researchers Notable journals
1890s Cross-education Edward Scripture Studies from Yale Psychological Laboratory
1900–1939 n/a n/a n/a
1940s Progressive resistance exercise introduced Thomas DeLorme Arch Phys Med Rehabil
ST studied as treatment for motor impairments Frances Hellebrandt J Bone Joint Surg
ST in youth introduced
1950s First studies on ST and muscle hypertrophy Edward Capen Arch Phys Med Rehabil
ST for psychological health introduced Frances Hellebrandt Phys Ther Rev
“Muscle boundness” and ST effect on movement speed and flexibility studied Donald Rose Res Q
1960s ST for older adults introduced Richard Berger Arch Phys Med Rehabil
First studies on “spot reduction” Jorgen Hansen Int Z Angew Physiol
ST for knee rehabilitation Helen Hislop J Appl Physiol
Isokinetic training introduced in 1967 Karl Klein J Assoc Phys Ment Rehabil
Circuit training introduced in 1969 Jack Leighton Res Q
ST load on strength gains examined by Berger Gene Logan
Sports science and ST on sport-related outcomes George McGlynn
Continued study of “muscle boundness” and ST effect on movement speed and flexibility Philip Rasch
1970s ST + anabolic steroids on muscle size and strength David Costill Am Corr Ther J
ST on muscle biopsy outcomes Pavo Komi Arch Phys Med Rehabil
Isokinetic training undergoes further study Duncan MacDougall Eur J Appl Physiol Occup Physiol
Larry Shaver J Appl Physiol
Alf Thorstensson J Sports Med Phys Fitness
Jack Wilmore Med Sci Sports
Res Q
Scand J Rehabil Med
*ST = strength training.

Three hundred twenty-one articles were published before 1980 on the effects of strength training in humans. The first was published in 1894 (324). Edward Scripture's study (324) was the first article on “cross-education” published in the English literature. In the study, one female subject completed 2 weeks of daily grip training with her right hand plus “dumbbell exercise” with “both arms” on some days (324). The subject improved her right and left grips 68.8 and 42.9%, respectively. Because left grip training was not performed, Scripture concluded increased strength of the left hand was due to “indirect practice” or “cross-education.” Scripture's results led to further investigations on “cross-education.” The current review discovered ∼14% of studies published before 1980 addressed “cross-education.” The long-lasting influence of Scripture's finding is described elsewhere (20).

After studies by Anderson in 1899 (7) and Wissler and Richardson in 1900 (391), there was a 41-year gap until Maison's article on strength training with blood flow restriction (221). Then, in 1945, Thomas DeLorme published results on heavy resistance exercise to restore muscle strength in patients with motor impairments (90). From 1946 to 1949, a number of strength training studies were published in rehabilitation journals.

The increased attention on strength training in the 1940s stemmed from global and national events. World War I (1914–1918), the poliomyelitis epidemic, and World War II (1939–1945) led to the creation of the physical therapy profession in the United States (139,245), and DeLorme designed the system of progressive resistance exercise to rehabilitate injured soldiers and patients with poliomyelitis (361). The lack of attention given to strength training before these events might have been due, in part, to the fact that strength training was often viewed as dangerous or counterproductive to health (360–362). Investigators of 3 studies published between 1894 and 1900 incorporated strength training into their studies (7,324,391), but they did so to understand human physiology and motor control, with applications to medicine and physical education secondary.

In the 1950s, the number of strength training studies grew further, followed by a surge in the 1960s and then no further increase in the 1970s. One possible explanation for the lack of increase in the 1970s was pioneering researchers, such as DeLorme, Frances Hellebrendt, Philip Rasch, and Richard Berger, were conducting fewer training studies at that time. Also, case studies became less common in the 1970s. This was probably because the safety and effectiveness of strength training and its therapeutic potential had been established in preceding decades, rendering case studies less novel, and simultaneously the standards for demonstrating effectiveness were increasing (i.e., controlled trials).

Four of the most prolific and influential researchers from this era were DeLorme, Hellebrendt, Rasch, and Berger. DeLorme developed the scientific system of progressive resistance exercise (361). His 1945 article on heavy resistance exercise to restore muscle strength in patients with motor impairments is the second most cited article from this era. His career and contributions are described elsewhere (184,185,361).

Hellebrandt et al. were some of the first to examine DeLorme's system of progressive resistance exercise (142,155). Hellebrandt also conducted some of the first investigations on “spot reduction” (61,321) and was the first to study the physiology behind Scripture's “cross-education” and consider its therapeutic potential (142). Hellebrandt's career and contributions to the fields of physical rehabilitation and exercise physiology are described elsewhere (158,395).

Berger was a pioneer of early strength training research because he systematically examined how training load and volume impact muscle strength. His 10 articles in the 1960s contributed to the substantial increase in articles published in this decade. Berger's career and contributions are described elsewhere (184,185,365).

Philip Rasch's contributions have not been well recognized. No biographical accounts of his life and research have been published. Rasch was well versed in the history of kinesiology and physical medicine (289–294,296,297). He published on a range of topics. He appears to be the first to have examined both the effects of strength training on mental health outcomes (298) and the effects of strength training with protein supplementation on muscle size and strength (301). Rasch also coauthored articles with Pierson on injuries associated with isometric training and the effects of strength training on movement speed (282,283). One of Rasch's primary interests was muscle hypertrophy with training (295,299–302,304). In 1955, before undertaking much of his own work, Rasch reviewed the literature on hypertrophy (290). Like others from that era (149,313,314,374), he concluded training-induced increases in muscle size, when they occur, are not key contributors to increased muscle strength. In 2016, Buckner et al. (51) revisited this “problem of muscle hypertrophy” and concluded Rasch's views are still valid because contemporary researchers have relied too heavily on cross-sectional and correlational designs. This topic continues to be debated, and causal mediation analysis has been recommended to resolve it (269).

Results from the current review support the notion of “hyperauthorship” or “promiscuous coauthorship” in scientific publishing (79,172,180,181). “Hyperauthorship” refers to the increase in the number of article authors over time, which is not fully explained by increased funding or complexity of research (171). In contemporary exercise science, articles typically have 3–5 authors, with only 2.6% as single-author articles (180,181). The current analysis revealed strength training articles published before 1980 had a mean of 2 authors per article, and ∼45% of articles were single-author articles.

The primary purpose of early strength training research was to determine if strength training was effective at restoring muscle function in patients with physical disabilities. Thus, injury/rehabilitation was one of the most common themes in this early era of strength training research. Approximately, 1 in 5 articles included patient groups. Patient impairments included poliomyelitis (190,240,276,318,345), cerebral palsy (138), limb paralysis from stroke or spinal cord injury (105,121,160), low back pain (87,111), and joint and bone disabilities (69,77,80,90,94,95,174,176–179,312). Medical and rehabilitation journals, such as Archives of Physical Medicine and Rehabilitation, were common outlets for this research. The Journal of the Association of Physical and Mental Rehabilitation (renamed American Corrective Therapy Journal in 1967) was also identified as a key journal.

The potential for strength training to improve health and function in healthy individuals was also quickly recognized by early researchers. Consequently, physical fitness for the general population was one of the most popular research themes during this early era of strength training research. In fact, by 1979, the most common research subject was a healthy university student, who was usually a male or a student enrolled in a physical education, medicine, or physical therapy program—likely samples of convenience. Nevertheless, a variety of groups continued to be studied, and researchers began publishing in physical education, sports medicine, gerontology, rheumatology, and ergonomics journals.

In the 1970s and 1980s, concerns were expressed about the injurious consequences of strength training in children and adolescents (108,234). Missing from such discussions was the fact that youths were subjects in strength training research in preceding decades. Before 1980, 1 of 10 strength training studies included subjects aged <18 years. The first study to include youths was published in 1946 (376). Wedemeyer (376) reported 2 months of sit-up training improved sit-up performance in 47 high school boys. The first study to include external loading with free weights in youths was published in 1949 (118). Gallagher and DeLorme (118) reported progressive resistance exercise of the hip and knee extensors improved muscle strength in boys with knee injuries. In 1952, DeLorme et al. (92) reported progressive resistance exercise did not slow muscle contraction time in boys. In 1954, Russell (318) reported in Lancet that strength training increased strength in youths and adults with poliomyelitis.

No injuries were reported in the 34 strength training studies that included youth subjects between 1894 and 1979. However, Kusinitz and Keeney (191) were the only researchers to make an explicit comment on adverse events. They stated medical examinations revealed no injuries in 23 boys who completed 8 weeks of free weight training (191). Thus, findings from this early era of research support the National Strength and Conditioning Association's conclusion that properly designed and supervised strength training programs are safe for youths (108).

Men and women aged ≥65 years were subjects in ∼4% of early strength training studies. The first study with an explicit focus on older adults was published in 1961 (280). Perkin and Kaiser (280) observed increased muscle strength in a group of 20 older adults who completed 6 weeks of isometric and isoinertial lower-limb training. Approximately 40% of the gain in muscle strength was retained when measured 5 months later. Moreover, “[n]o evidence of joint trauma was observed from the exercise in any of the subjects” (280).

Strength training studies with older adults were published, albeit in small numbers, throughout the 1960s and 1970s. In the 1970s, gerontology journals began publishing strength training studies (65,68,173,204). A common topic was the effect of training on joint stiffness and arthritis (65,68,218,322). Interventions were well tolerated. For example, after 7 weeks of strength training in patients with rheumatoid arthritis, Machover and Sapecky (218) reported no “adverse systemic reaction and no local flare-up of any exercised or control joint.”

Athletes were not the main focus of early strength training research. About 6% of strength training studies from this era included athletes or addressed questions of sports science. The first study to assess the effects of strength training on physical performance in athletes was published in 1899 (7). Anderson's article (7) included 6 different experiments that addressed questions of motor control, such as “cross-education” and “transfer.” Some of the men in the study were “excellent gymnasts and athletes” (7). The next strength training study to include athletes was a case report in the Journal of the American Medical Association in 1959 (312). Rose (312) reported “cross-education” and improved muscle strength and clinical outcomes in 3 athletes with knee injuries who performed unilateral strength training of the knee extensors. In the 1960s and 1970s, the number of studies that included athlete subjects increased. Hockey players (3), baseball players (48,356), dinghy sailors (394), and female sprinters, tennis players, and volleyball players (274,343,369) were all subjects in studies. One specific topic of interest was whether throwing with overload improves throwing velocity and accuracy (discussed below).

Most strength training interventions were 4–8 weeks and involved 3 training days per week. The elbow flexors and knee extensors were the most commonly exercised muscle groups. Isometric, isokinetic, and isoinertial contractions were all incorporated into training programs but to varying degrees.

Isometric contractions were the second most frequent type of contraction performed in interventions. Interest in isometric training stemmed from an article published in 1953 (148). Hettinger and Muller (148) examined effects of various doses of isometric training on muscle strength. Their findings influenced strength training research throughout the 1950s (225,287,393) and led to studies such as whether isometric training in the form of partner-provided manual resistance could improve physical fitness in high school boys (393). Also, in the early 1960s, isometric training was promoted by Bob Hoffman and the York Barbell Company and was intertwined with the history of the anabolic steroid Dianabol (109,363).

Isokinetic training was not common in early strength training research. The concept was not developed until the late 1960s. The creator of isokinetics was James Perrine. On September 14, 1965, Perrine submitted a patent application (“Isokinetic exercise processes and apparatus” No. 3,465,592) to the U.S. Patent and Trademark Office. In 1967, Perrine and Hislop introduced isokinetics to the physical rehabilitation profession (151). That same year, the first isokinetic training study was published (355). Thistle et al. (355) reported 8 weeks of isokinetic training of the knee extensors led to greater improvements in peak force than 8 weeks of isometric and isoinertial training. In 1968, Perrine introduced isokinetics to physical educators (281). In 1969 (246) and 1970 (247), Moffroid et al. used an isokinetic device to test whether adaptations to training are specific to the type and speed of muscle contraction during training. That same year, on September 9, Perrine's patent was approved.

Isoinertial contractions (eccentric + concentric) were the most common. DeLorme's system of progressive resistance exercise used such contractions and thus contributed to their proliferation within research training programs.

Circuit training, a form of isoinertial strength training, was examined in 16 articles. The first study on circuit training was published in Ergonomics in 1959 (1). Adamson (1) reported increased muscle strength, muscle endurance, and power in 20 university students after 8 weeks of training with a 12-exercise circuit (1). One year later, Nunney (266) examined the effects of circuit training on swim performance. Two other studies in the 1960s examined circuit training (17,156). In the 1970s, interest in circuit training grew, and its safety and effectiveness were tested in cardiac patients (253), mentally handicapped individuals (260), and geriatric patients with mental health problems (68). The development of Nautilus machines is also believed to have contributed to the increased number of studies on circuit training in the 1970s (185).

The first study to examine eccentric strength training was published in 1960 (42). Bonde Petersen (42) observed 20–36 days of maximal eccentric contractions of the elbow flexors did not improve isometric strength of the elbow flexors, whereas isometric training of the elbow flexors improved isometric strength. The results provided evidence of training specificity. Seven years later, Singh and Karpovich (332) reported 8 weeks of maximal eccentric contractions of the elbow extensors improved both elbow extensor and elbow flexor strength, irrespective of whether strength was measured eccentrically, concentrically, or isometrically. A number of studies then compared the effects of eccentric and concentric training (163,165,182,196,222). Approximately 17% of articles from this era addressed the topic of muscle contraction type.

Five studies between 1966 and 1970 examined effects of weeks of throw/serve training with overload on throw/serve accuracy or velocity (48,211,212,286,346). Results were mixed. Logan et al. (211,212) reported throwing with overload was more effective at increasing throw velocity than training without overload. Findings from other researchers suggested throwing/serving with overload did not benefit throw/serve velocity or accuracy (48,286,346).

Five percent of studies from this early era of strength training research examined the effects of strength training plus diet or supplementation on health or function. The first of 13 studies from this era to examine effects of strength training with anabolic steroids on changes in anthropometrics and muscle strength was published in Science in 1969 (168). Interest in strength training with anabolic steroids continued into the 1970s (9–11,62,107,114,145,167,213,341,348,375). Only 2 studies from this era examined effects of supplemental protein on training adaptations (301,367).

Isometric MVCs were the most common test of muscle strength. Muscle groups most commonly tested with MVCs were knee extensors, elbow flexors, elbow extensors, and hand grip muscles. An isometric strength test that was used by some investigators in this era, but is not commonly used in contemporary research, is the back and leg dynamometer. Sargent appears to have been the first to recommend the back and leg dynamometer to measure muscle strength (320). Early versions of the device consisted of a spring dynamometer or balance, a handle held in the subject's hand, and a chain that connected the handle to the dynamometer (21,320). The device was used to assess strength of the back extensors and strength of the hip and knee extensors in 2 separate tests. For the test of the back extensors, the knees were fully extended while the subject pulled up on the chain. For the test of the hip and knee extensors, which is a field test of the modern-day isometric midthigh pull (46), the knees and hips were bent while the subject pulled up on the chain. Photographs of the 2 positions can be seen in Cureton and Larson's 1941 article on muscle strength as a component of fitness (81).

The second most common test of strength was the 1RM. Interest in the 1RM stemmed from the fact 1RMs were part of DeLorme's system of progressive resistance exercise (90). The bench press was the most common 1RM test.

Around 1950, researchers began to study the effects of strength training on overall physical fitness. Capen (56) examined how 11 weeks of weight training impacted muscle strength (grip, back lift, and leg lift), muscle endurance (chin-ups, push-ups, and sit-ups), power (broad jump and vertical jump), and cardiovascular endurance (300-yd shuttle run). Moreover, part of the interest in power and speed of movement stemmed from controversy surrounding “muscle boundness”—the idea strength training causes muscle tightness or hypertrophy that reduces joint ROM, movement speed, and coordination. Capen's study was the first of 15 studies from this era to test the validity of “muscle boundness.” Capen's results did not support the concept, as performance on “speed events” (e.g., vertical jump) improved after weight training (56). In 1952, DeLorme et al. (92) also tested “muscle boundness” and found no support for it. Four months of isoinertial strength training had no effect on contraction time of elbow flexors and made contraction time of knee extensors faster (92). In the mid-1960s to late 1960s, researchers continued to test if increased muscle strength from strength training might actually improve contraction speed (75,219). Overall, the findings suggested strength training either improves movement speed or has no impact on it.

Seventeen studies examined changes in flexibility or joint ROM after strength training. Most of these studies involved measurements of joint ROM using goniometers or similar tools. Only 2 studies examined the effects of strength training on the sit-and-reach test (191,389), which was developed in 1952 (380).

Some studies were conducted under the purview that strength training might restore ROM in individuals with physical disabilities. DeLorme often reported the effects of strength training on his patients’ joint ROM (90,91,95). Moreover, the notion strength training might increase joint ROM was investigated in groups such as older adults (65), patients with hand arthritis (322), and children with cerebral palsy (138).

Other investigations were conducted under the purview of “muscle boundness”—that strength training might decrease joint ROM in healthy individuals. The first study to test this was published in 1956 (224). Massey and Chaudet (224) found weight training for 4 months “did not have an appreciable effect upon range of joint movement throughout the body.” In 1960, Wickstrom (384) reported 12 weeks of weight training in male university students caused “statistically significant increases in strength without interfering significantly with flexibility.” In a case study published in 1964, Leighton (198) reported ROM of 27 of 30 joints increased in a single subject who completed 8 weeks of weight training. In 1966, Gardner (120) reported 6 weeks of isometric or isotonic strength training in male university students had little impact on flexibility. In 1967, Leighton et al. (199) reported 8 weeks of various types of strength training had no impact on ROM at the elbow, hip, and knee. Thus, this early era of research debunked the notion of “muscle boundness.” A recent review has concluded strength training through full ROM generally increases flexibility (268).

Strength training was introduced into the medical field for the purpose of restoring muscle function in people with existing injuries. Only one study from this era examined the possibility that strength might prevent future injuries in healthy individuals (24). In 1964, Bender et al. (24) reported fewer noncontact knee injuries in a group of 150 military cadets who completed 6 months of isometric training of the knee extensors and flexors than a group of 150 military cadets who did not complete the training.

Concerns in the 1970s and 1980s about strength training causing injuries were not supported by research findings in preceding decades. One factor that might have contributed to this contradiction was that researchers rarely commented on adverse events in their articles. Consistent with poor reporting of adverse events in contemporary strength training research (207), only 14 articles (4.1%) from this era included comments related to adverse events (15,39,62,85,87,114,155,168,191,193,218,253,283,341). Some of the comments pertained to anabolic steroids rather than strength training (62,114,168,341). Some investigators probably did not comment on adverse events because few, if any, occurred. For example, Ball et al. (15) stated “[a]lthough there were nearly 1,500 maximal efforts during the study no injuries occurred.”

Nevertheless, adverse events occurred in 3 studies (85,155,283). Houtz and Hellebrandt (155) discontinued heavy resistance exercise of the quadriceps because “knee joint pain of intermediate significance developed in every subject.” Pierson and Rasch (283) in their article titled “The injurious consequences of maximal isometric arm exercises” provided a detailed report on injuries from exercise. Fifteen university students performed isometric training of the elbow flexors (2 weeks; 5 days per week). The training “resulted in severe arm and forearm pains for 11 of the 15 subjects,” and 10 subjects described the pain as being similar to “shin splints” (283). Pierson and Rasch reported the mean increase in isometric strength in injured and noninjured subjects was 0 and 16.3 lbs, respectively. The investigators believed their findings explained why conflicting results on the effectiveness of isometric exercise had been reported in previous articles (283).

Kraemer et al. (185) stated “[o]nly a few studies examined cardiovascular responses to [strength training] before 1980.” This conclusion is not fully supported by the current analysis. From 1894 to 1979, 57 articles reported on the effects of strength training on cardiovascular outcomes (e.g., step test and V̇o2). The first was Capen's 1950 article on “muscle boundness” which reported that the magnitude of improvement in 300-yd shuttle run time (∼6%) after 11 weeks of weight training was the same as after 11 weeks of general conditioning (running and gymnastics) (56). The first study to have a more explicit focus on cardiovascular outcomes was published in 1960 (259). Nagle and Irwin (259) reported neither low-load nor high-load weight training improved cardiovascular outcomes (e.g., heart rate and V̇o2) in university students when compared with a control condition (i.e., archery). Effects of strength training on cardiovascular outcomes in cardiac patients were examined in the 1970s (173,253).

Some researchers considered strength training might improve mental health outcomes and that psychological factors might impact training adaptations. Rasch's 1956 article, “The role of weight training in a neuropsychiatric hospital,” was the first to report on the effects of strength training on mental health (298). Rasch (298) provided a rationale for using strength training in mental health patients, described 14 strength exercises to prescribe to mental health patients, and summarized effects of strength training on 4 patients in a neuropsychiatric hospital (298). According to Google Scholar, Rasch's article has never been cited.

Thirteen years passed until the next study that included mental health patients. In 1969, Mannheimer (222) found concentric and eccentric trainings of the elbow extensors were equally effective at improving muscle strength in 32 veterans in a neuropsychiatric hospital. However, Mannheimer (222) did not measure mental health outcomes. The next year, in 1970, both Morgan et al. (252) and Smith and Figetakis (339) examined effects of strength training on mental health. Morgan et al. (252) reported 6 weeks of circuit training did not improve self-rated depression. However, most subjects in the study were not depressed at baseline (252). Smith and Figetakis (339) reported that 3–4 months of isometric training of upper-body and lower-body muscles had little impact on psychological health in patients with schizophrenia. The authors stated “motivation of the subject to perform the exercise at maximal or required levels was the main problem in conducting such a program” (339). Other psychology topics included: strength training for mentally handicapped individuals (49,260), effects of mental practice on strength gains (170), and effects of motivational techniques on strength improvements (133,166,208).

Kraemer et al. (185) identified studies of surface EMG and “reflex potentiation” in the mid-1970s as the start of research into training-induced neural adaptations. However, some strength training studies published before the mid-1970s reported on surface EMG and tendon reflexes. In 1954 (275) and again in 1962 (276), Partridge presented raw EMG traces from patients as they progressed through strength training programs. In 1968, 4 studies (115,344,345), including deVries' study (98) on “efficiency of electrical activity,” examined surface EMG before and after training. Also, some researchers in the late 1950s and 1960s included EMG as part of supplementary experiments within larger training studies. These researchers did not examine changes in EMG with training, but they did address other aspects of motor control that might explain the training results. For example, researchers who presented results from training studies also presented results from studies that examined the influence of posture on muscle activity (121) and the degree of antagonist activation during agonist contraction (332). Moreover, the patellar tendon reflex was measured in 3 strength training studies before the mid-1970s (11,12,113).

The studies by Milner-Brown et al. (243) and Moritani and deVries (254) warrant brief discussion. The study by Milner-Brown et al. (243) in 1975 is the third most frequently cited article from this era (560 citations). One reason it is frequently cited is because it was the first to include recordings from single motor units before and after training. Six weeks of strength training of the first dorsal interosseous in 4 subjects caused enhanced motor unit synchronization (243). The study by Moritani and deVries (254) in 1979 is the most frequently cited article from this era (1,815 citations). Seven healthy young men and 8 healthy young women completed 8 weeks of unilateral dumbbell biceps curls (254). The training caused increased isometric strength of the elbow flexors of both arms, increased EMG of the elbow flexors of both arms during MVCs, and increased estimated cross-sectional area of the elbow flexors of the trained arm. The study provided evidence of cross-education. However, the main reason it is cited is because of its conclusion regarding the time course of neural and muscle adaptations to strength training. The authors posited increased strength within the first 4 weeks of training is due primarily to neural adaptations, whereas increased strength thereafter is due to hypertrophy (254).

Finally, although neurophysiological techniques were not widespread in early strength training research, discussions about neural adaptations were. A number of researchers speculated that motor learning and neural adaptations likely caused increased muscle strength with training (149,155,299,374).

Early strength training research was concerned with whether strength training could restore both muscle strength and muscle size. To quantify muscle hypertrophy, researchers relied on limb girths. Approximately 1 of every 5 strength training articles included girth measurements. Given that girth measurements do not distinguish between tissue types, imaging techniques were later adopted. In 1970, Ikai and Fukunaga (159) meausred muscle cross-sectional area with imaging ultrasound. They reported 100 days of unilateral isometric training of the elbow flexors increased muscle strength and cross-sectional area of the exercised muscles (159). Nine years passed before the technique was used again in strength training research (102,188).

Muscle biopsies were also taken from subjects in some early strength training studies (∼5%). In 1969, both Morgan et al. (251) and Penman (278) acquired muscle biopsies from male subjects before and after strength training. Morgan et al. (251) reported on changes in lipid composition, whereas Penman (278) reported on changes in sarcomere length, A-band and I-band lengths, Z-band width, myofibril number, etc. In 1970, Penman (279) conducted a second study on the topic. After 10 weeks of strength training, 3 male subjects exhibited increased muscle strength, no change in limb girth, and various changes in microscopic features of the muscle. Between 1976 and 1979, the use of muscle biopsies became more common in strength training research.

“Spot reduction”—the notion exercise performed with a specific body will reduce the amount adipose tissue of that body part—was also of interest to some early researchers. Eight studies, usually comprised of female subjects, addressed “spot reduction” (61,161,188,227,241,248,273,321). The first study was published in 1960 (61). Carns et al. (61) reported no differential effect of 8 weeks of localized spot exercise vs. generalized exercise on body segment volumes. Similar findings were reported in 1962 by Schade et al. (321). In 1965, Mohr (248) reported 4 weeks of isometric abdominal exercises reduced girths and subcutaneous adipose tissue at the waist.

Historical reviews are important because they help clarify why things are the way they are. As Philip Rasch remarked in 1960, studying history may also “give us some idea of where we are going” (294). The current review informs the study of the history of strength training research. It includes an inventory of the earliest strength training studies and quantitative descriptions of study characteristics. The results serve multiple functions. First, they elucidate the purposes of early strength training research. Second, they provide a broader, historical perspective regarding the safety and effectiveness of strength training. Third, they provide objective data to compliment future narrative and biographic accounts. Fourth, they provide baseline information for future work on trends in strength training research over time. Finally, the inventory can be used by researchers to identify studies from this era that might be eligible for systematic reviews and meta-analyses.

Practical Applications

Scientific studies conducted between 1894 and 1979 were the first systematic attempts in man's history to understand how strength training affects the human body. Knowledge discovered during this era has had long-standing implications for exercise practitioners. First, researchers from this era documented that strength training restores muscle function in patients with neuromuscular and musculoskeletal impairments. Second, they found strength training is safe when performed by healthy individuals, patient populations, older adults, and children and adolescents. Third, they observed strength training improves various measures of physical health and fitness. Fourth, they refuted the concept of “muscle boundness,” as strength training does not typically hinder movement speed or joint ROM. Finally, they documented “cross-education” and discussed its potential therapeutic implications.

Acknowledgments

The author has no conflicts of interest to report. No funding was received for this work. The results and discussion in the present review do not constitute endorsement by the National Strength and Conditioning Association (NSCA).

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    Keywords:

    exercise science; muscle strength; resistance training; physical therapy; progressive resistance exercise

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