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Scanning Sports Medicine

Latest Clinical Research Published by ACSM

Kiningham, Robert B. MD, FACSM

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Current Sports Medicine Reports: June 2019 - Volume 18 - Issue 6 - p 183-184
doi: 10.1249/JSR.0000000000000607
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Exercise Arrangement Is Associated with Physical and Mental Health in Older Adults

The health benefits of exercising consistently are well-documented for all age groups, and clinicians are strongly encouraged to recommend exercise to all of their patients. However, although the specifics of intensity and frequency have been extensively studied, there is less known about the impact of the social setting in which exercise is done. This cross-sectional study, published in the June 2019 issue of Medicine & Science in Sports & Exercise® (MSSE) compared the effect of exercising alone, exercising in groups, and not exercising, on validated survey measurements of physical activity (PA), physical function (PF), and mental health in a cohort of healthy older adults (1).

Subjects were identified from a randomized and stratified sampling of independent living, nondisabled adults ages 65 to 84 years living in Ota City, Tokyo, Japan. Each subject's exercise arrangement was classified as “nonexerciser,” “exercising alone,” or “exercising with others” based on their response to the question “who do you usually exercise with (more than once a week)?” If a subject responded that he or she exercised both alone and with others, they were classified as “exercising with others.”

The three dependent variables were PA as measured by the International Physical Activity Questionnaire (IPAQ-SF), PF determined by the Motor Fitness scale, and mental health (MH) as determined by the WHO-Five Well-Being Index. The IPAQ-SF estimates the minutes per week spent in moderate and vigorous physical activity (MVPA). MVPA greater than 150 min·wk−1 was defined as PA sufficiency. The Motor Fitness scale consisted of 14 yes-no questions regarding the ability to do specific tasks. Lower PF was defined as a total score of ≤11 in men and 9 in women. The WHO-Five consists of five items that assess positive well-being during the previous 2 weeks on a 6-point (0–5) Likert scale. Worse MH was considered a total score less than 13. A number of possible co-variates also were measured, including living situation, marital status, social activity, self-report BMI, tobacco smoking status, employment, and number of chronic diseases.

Complete surveys were obtained from 4,007 men and 3,752 women representing a 77% response rate. Among men, 72.3% were classified as exercising (45.9% exercising alone and 26.4% exercising with others). Among women, 70.1% were exercising (30.3% alone, 39.8% with others). Women were significantly more likely than men to exercise with others. Among the subjects who exercised with others, men were more likely to exercise with family members and friends of the opposite sex, while women were more likely to exercise with friends of the same sex and with exercise trainers. There was a significant group trend for greater MVPA per week, PF, and MH from nonexerciser to exercising alone to exercising with others. Multi-regression analysis adjusted for all measured co-variates found that both men and women exercising alone or with others had greater MVPA sufficiency, higher PF, and better MH scores than nonexercisers. In both men and women, exercising with others was more likely than exercising alone to achieve PA sufficiency and better MH. However, there was no statistical difference on PF between exercising alone and with others for both sexes.

The study findings are certainly consistent with previous studies that have found that exercising in groups can improve physical activity and has MH benefits. The strength of the study is the number of subjects and high survey response rate, and that it deals with an understudied population of older adults. The study results appear to indicate that exercising in groups leads to more MVPA per week and better MH, but like all cross-sectional studies, has the limitation of self-selection. It may be that more active and/or healthy people chose to exercise with others. Also, the study does not tell us if changing from exercising alone to exercising with others will increase MVPA per week or improve MH. Forcing someone who would rather exercise alone to exercise with others may have a negative impact. The study tried to account for social factors that may predispose to the exercise arrangement, but it is impossible in a cross-sectional study to completely account for these factors. Another limitation is that the population was exclusively Japanese. There may be a different impact of exercise arrangement in other cultures.

Bottom line: Japanese older adults who exercise in groups or alone reach sufficient MVPA, have better physical functioning and mental health (MH) scores compared with adults who do not exercise. Older adults who exercised with others were more likely to achieve sufficient MVPA per week and have better MH than adults who exercised alone.

Similar Isokinetic Strength Preinjury and at Return to Sport after Hamstring Injury

Return-to-play decisions after an injury are more of an art than a science. Hamstring injuries are particularly difficult because of their chronicity and high reinjury rate. Many clinicians use strength as a guide and will require the injured hamstring to be at least 90% as strong as the uninjured hamstring before return to play. In this study, also from the June 2019 issue of MSSE, Van Dyk and colleagues questioned the evidence for such a recommendation and looked at basic strength characteristics of professional soccer players who sustained hamstring injuries (2).

Data from professional soccer players involved in two hamstring strain treatment studies were analyzed. All athletes had baseline isokinetic knee flexion and extension strength testing as part of their preseason health evaluation. Concentric knee flexion and extension strength were measured at 60°·s−1 and 300°·s−1, whereas eccentric knee extension at 60°·s−1 measured the eccentric strength of the knee flexors. Athletes who subsequently sustained an acute hamstring injury confirmed on MRI were included in the study. All athletes underwent a standardized rehabilitation protocol based on functional criteria for advancement. Athletes had to be able to demonstrate full sports-specific functional ability without limitation or symptoms before being evaluated by the treating sports medicine physician for possible return to sport (RTS). At the RTS evaluation, knee flexion and extension isokinetic strength were measured in an identical manner as that during the preseason baseline.

A total of 41 athletes, age 25 ± 4 years, were evaluated. There were 21 grade I (muscle edema without tissue damage on MRI) and 20 grade II (partial muscle tear) injuries. The majority (73.1%) of the injuries were in the long head of the biceps femoris, with 22.0% in the semimembranosus and 4.9% in the semitendinosus. Average RTS was 25.3 ± 8.9 d.

At RTS, the average strength of the injured leg was >95% of preinjury strength on all measurements. Concentric hamstring strength at 60°·s−1 was statistically less than baseline, but still at 95.9% of preinjury strength. As a result of the rehabilitation, eccentric hamstring strength at RTS was greater than preinjury for both the injured and uninjured legs. Strength differences between legs was common at baseline and at RTS, with approximately 60% of players having at least one negative or positive isokinetic hamstring strength difference of more than 10%. There was no association of strength discrepancy (relative weakness or strength) with subsequent injury site. The study was not designed to evaluate the impact of strength discrepancy and reinjury rate, although it was noted that there was only one hamstring reinjury after 2 months of RTS.

This study has several provocative findings that challenge the “within 10%” equal strength criteria for RTS. Strength discrepancies between legs are common, often exceeding 10%, and do not appear to predict injury site. The authors also point out that day-to-day variation in the isokinetic strength measurement of knee flexion and extension exceeds 20%, so the reliability and precision of the measurement makes decision making based on strength questionable. A weakness in the study design was that the treating physical therapists and the physicians who made the decision to RTS were not blind to the strength measurements. However, this would seem to make the differences in strength between legs less if athletes were pushed to equal their strength before RTS. It also would have been useful if baseline strength data was provided for uninjured players. Perhaps, strength discrepancy itself, both “positive” and “negative,” somehow predisposes to hamstring injuries.

Bottom line: Return-to-play decisions after hamstring injury in soccer players should not be based strictly on strength comparisons between the injured and uninjured legs.


1. Seino S, Kitamura A, Tomine Y, et al. Exercise arrangement is associated with physical and mental health in older adults. Med. Sci. Sports Exerc. 2019; 51:1146–53.
2. van Dyk N, Wangensteen A, Vermeulen R. Similar isokinetic strength preinjury and at return to sport after hamstring injury. Med. Sci. Sports Exerc. 2019; 51:1091–8.
Copyright © 2019 by the American College of Sports Medicine