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Retrospective Injury Epidemiology of Strongman Athletes

Winwood, Paul W.1,2; Hume, Patria A.1; Cronin, John B.1,3; Keogh, Justin W.L.1,4,5

Journal of Strength and Conditioning Research: January 2014 - Volume 28 - Issue 1 - p 28–42
doi: 10.1519/JSC.0b013e3182986c0c
Original Research
Free

Winwood PW, Hume PA, Cronin JB, and Keogh JWL. Retrospective injury epidemiology of strongman athletes. J Strength Cond Res 28(1): 28–42, 2014—This study provides the first empirical evidence of strongman training and competition injury epidemiology. Strongman athletes (n = 213) (mean ± SD: 31.7 ± 8.8 years, 181.3 ± 7.4 cm, 113.0 ± 20.3 kg, 12.8 ± 8.1 years general resistance training, and 4.4 ± 3.4 years strongman implement training) completed a self-reported, 4-page, 1-year retrospective survey of physical injuries that caused a missed or modified training session or competition. Analysis by age (≤30 and >30 years), body mass (≤105 and >105 kg), and competitive standard (low and high level) was conducted. Eighty-two percent of strongman athletes reported injuries (1.6 ± 1.5 training injuries per lifter per year, 0.4 ± 0.7 competition injuries per lifter per year, and 5.5 ± 6.5 training injuries per 1,000-hour training). Lower back (24%), shoulder (21%), bicep (11%), knee (11%), and strains and tears of muscle (38%) and tendon (23%) were frequent. The majority of injuries (68%) were acute and were of moderate severity (47%). Strongman athletes used self-treatment (54%) or medical professional treatment (41%) for their injuries. There were significantly more competition injuries for the ≤30- than the >30-year athletes (0.5 ± 0.8 vs. 0.3 ± 0.6, p = 0.03) and >105-kg athletes compared with the ≤105-kg athletes (0.5 ± 0.8 vs. 0.3 ± 0.6, p = 0.014). Although 54% injuries resulted from traditional training, strongman athletes were 1.9 times more likely to sustain injury when performing strongman implement training when exposure to type of training was considered. To reduce risk of injury and improve training practices, strongman athletes should monitor technique and progressions for exercises that increase risk of lower back, shoulder, bicep, and knee musculoskeletal injuries. Clinicians should advise athletes who use of strongman resistance training programs can increase injury risk over traditional exercises.

1Sport Performance Research In New Zealand (SPRINZ), AUT Millennium Institute, AUT University, Auckland, New Zealand;

2Bay of Plenty Polytechnic, Department of Sport and Recreation, School of Applied Science, Tauranga, New Zealand;

3Edith Cowan University, School of Biomedical and Health Sciences, Perth, Australia;

4Bond University Research, Center for Health, Exercise and Sports Sciences, Faculty of Health Sciences and Medicine, Bond University, Gold Coast, Australia; and

5University of the Sunshine Coast, Faculty of Science, Health, Education and Engineering, Queensland, Australia

Address correspondence to Paul W. Winwood, paul.winwood@boppoly.ac.nz.

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Introduction

The sport of strongman is similar to the sports of weightlifting, bodybuilding, and powerlifting in which weight training is the primary form of exercise. In the late 1970s and 1980s, strongman athletes primarily trained as powerlifters or weightlifters and incorporated some bodybuilding training principles. Modern-day strongmen are hybrid athletes who combine a variety of traditional resistance training with sport-specific implement training (32). Since the sport inception in 1977, the sport of strongman has grown in popularity in many countries, both as a spectator sport and in terms of active competitors. Strongman competitions are hosted at local, regional, national, and international levels and have divisions based on age, body mass, gender, and experience.

Some strongman events like the axle deadlift or log press are similar to those in weightlifting and powerlifting competitions where the athlete attempts to lift the heaviest load possible for one repetition or perform as many repetitions with the given load in a predetermined time limit. Other events such as the tire flip, farmer's walk, and yoke walk (Figure 1) are timed with the winner being the fastest athlete to complete the required distance. Movement patterns used in strongman events require the strongman-specific implements to be carried or held for longer periods, and through different ranges of joint motions, than the bars used for powerlifting and weightlifting events. Like weightlifters and powerlifters, strongman athletes exert maximum effort to beat their previous personal records and other competitors and as such may be placing themselves at relatively high risk of injury.

Figure 1

Figure 1

Injury epidemiology of powerlifting (2,19,27), weightlifting (5,27,28), and bodybuilding (9,18) provides critical information about injury prevalence and rates and some insight into causation. No injury epidemiology study has been undertaken with strongman athletes; only one case study (17) of a 38-year-old right hand–dominant strongman competitor was conducted. The athlete sustained a simultaneous acute supraspinatus tear and a distal bicep rupture while attempting a 300-pound (∼135 kg) overhead axle press. Although acute rotator cuff tear is commonly associated with tearing of the proximal bicep tendon (30), such an injury has not been reported in the literature to occur simultaneously with a distal bicep tendon rupture. Although only a case study, this injury may demonstrate that strongman athletes may be prone to potentially serious acute injuries that are not seen commonly during other physical activities.

Injury epidemiology knowledge would benefit strongman athletes and strength and conditioning coaches who wish to incorporate strongman event training into their athletes' training programs by providing the first empirical data on potential injury risk of strongman activities. The purpose of this study was therefore to provide the first empirical evidence of strongman training and competition injury epidemiology, with analyses by age, body mass, and competitive standard.

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Methods

Experimental Approach to the Problem

An online survey was used to provide retrospective descriptive epidemiology information about injuries associated with strongman implement training with analysis by age, body mass, and competitive standard. The procedures used were based on those recommended for sport injury epidemiology research (4). Although retrospective design has some limitations for injury epidemiology research because of injury recall (15,21), it seems that such issues are less problematic in athletes in the weight training sports who routinely keep training diaries (32). The use of a retrospective design is also warranted here as no strongman injury epidemiology studies have yet to be published, and of the 12 injury epidemiology studies published in powerlifting, weightlifting, and bodybuilding, 11 have used the retrospective approach (20).

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Subjects

This study was approved by the University Ethics Committee where the study was conducted. To meet ethical approval, all questions in the survey were answered on a voluntary basis. As a result, the number of strongman athletes responding to each question item varied. Participant response numbers are indicated in the Results.

Strongman athletes were recruited via multimedia methods similar to previously described procedures (32). The networking site “Facebook” was the primary method used to recruit the strongman athletes. Identified strongman athletes were sent a letter via e-mail. The letter contained an invitation to participate in the research and the link to the online survey. Presidents of strongman clubs in New Zealand, Australia, United States, and the United Kingdom were contacted to e-mail the survey to their club members. An information sheet outlining the objectives and purpose of the study was situated on the first page of the online survey. Participants were asked to indicate their consent by participating in the survey. http://www.surveygizmo.com/ was used to launch the electronic survey on the Internet.

Participant inclusion criteria were male strongman athletes who used a training diary and had at least 12 months current experience in using common strongman exercises like the tire flip, farmer's walk, and log press in their conditioning programs. Four hundred eight participants accessed the online survey, which included those who observed the survey, partially completed the survey, and the 213 who fully completed the survey. The criterion for a completed survey was that the participant completed the first 2 sections of the questionnaire on personal details and resistance training experience and at least one injury in the “previous injury” section if the athlete stated an injury had occurred.

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Subject Characteristics

Two hundred thirteen male strongman athletes from 19 countries completed the survey. Of the 213 strongman athletes, 175 athletes reported that a previous injury had occurred and completed the previous injury section of the survey. The strongman athletes were (mean ± SD) 31.7 ± 8.8 years, 181.3 ± 7.4 cm, 113.0 ± 20.3 kg, had 12.8 ± 8.1 years general resistance training experience, and had 4.4 ± 3.4 years strongman implement training experience.

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Research Instrument

Strongman athletes completed a self-reported, 4-page, 1-year retrospective Injury Epidemiology of Strongman Athletes survey (Appendix 1) created for this study based on a survey used with powerlifters (19). The original strongman survey was pilot tested with 3 university professors and then 3 strongman athletes to ensure its ease of use with strongman athletes. As a result of pilot testing, the survey was slightly modified, including clarifying wording of some questions before being submitted online.

The survey requested information on personal details (age, height, body mass, resistance training experience, and strongman training experience), resistance training characteristics (strongman implement use and training duration and frequency), previous injury, and injury risk factors. Participants were requested to detail their common/typical values for each question.

The injury section included questions on the nature of injuries (body site, type, onset, severity, first time, or repeated occurrence) received during both training and competition. The exercise and load as a percentage of one repetition maximum (1RM) resulting in injury and treatment type were ascertained. Injury was defined as any “physical damage to the body that caused the strongman athlete to miss or modify one or more training sessions or miss a competition” (2,19,27). Injured body sites were categorized as shoulder, neck, upper back, elbow, hip/buttock, knee, groin, chest, lower back, triceps, quadriceps, biceps, hamstrings, or other. Injury types were categorized as bruise, laceration/cut, muscle strain/tear, tendon strain/tear, ligament sprain/tear, cartilage damage, bone fracture/break, or other. Injury occurrence was categorized as first time or repeated. Classifications of injury onset (i.e., acute/sudden or chronic), severity of injury, and treatment and rehabilitation options were defined according to previously established methods (19). A moderate injury stopped the strongman athletes from performing an exercise, whereas a major injury stopped their training completely.

The time of injury in relation to the training phase (e.g., general preparation) and in the training session or competition (i.e., early, middle, or late) was ascertained. Injury-causing activities (events) were categorized as strongman implement training, traditional training, both strongman implement training and traditional training, or unknown. Strongman implement exercises were defined as exercises using any nontraditional training implements (e.g., stones, tires, etc.). Traditional exercises were standard exercises performed in the gym by regular weight trainers and strength athletes (e.g., squat, bench press, etc.).

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Statistical Analyses

Means and SDs were calculated for the participant characteristics and injury rates. Frequencies of responses were collated for questions related to the injury epidemiology of strongman athletes. Categorical and ordinal data were reported as both absolute numbers and percentage of responses. Scores for ranked questions were determined by weighted calculation in SurveyGizmo; items that were ranked first scored higher than the following ranks, so that the total score was the sum of all weighted ranks. Weighted calculations were based on the number of options represented. For example, the highest weighted score corresponded to the most dangerous strongman event. Injury rates were quantified according to previously established methods (19,27) and were calculated for all participants and the various subgroups of age (≤30 and >30 years), body mass (lightweight <105 kg and heavyweight ≥105 kg), and competitive standard (high level and low level). Masters' classes such as those seen in powerlifting are not generally seen in the sport of strongman; therefore, the age groups were chosen post hoc to allow for a similar sample size for group comparisons. A body mass of 105 kg was used to separate the athletes as the 2 most common bodyweight classes in strongman competition are ≤105 and 105 kg (open competition category). High-level strongman athletes were defined as those who had competed at a national or international competition or performed professionally.

A 2-tailed unequal variance t-test was used to determine if any statistical differences (p ≤ 0.05) existed in the demographics, training data, and injury rate of the strongman athletes as a function of age, body mass, and competitive standard. Differences among the subgroups regarding injury onset, injury severity, injury occurrence, and treatment type were analyzed with a chi-square test. All analyses were performed using Microsoft Excel (version 9.0; Microsoft, Seattle, WA, USA).

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Results

Demographics and Training Characteristics

Table 1 details the demographics and training characteristics for all 213 strongman athletes. Strongman athletes with significantly more strongman implement training experience had a higher competitive standard and were in the heavier body mass competition class. Although there was an average of 12.8 years of resistance training experience, only a third of those years included strongman implement training experience. In addition, weekly training using strongman implements accounted for a third of total resistance training time.

Table 1

Table 1

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Exposure Time to Event and Exercise

Strongman athletes ranked presses, lifts, and carries/walks as the 3 most commonly used strongman movement categories in their training programs. The tire flip, yoke walk, and stone lift were ranked as the 3 most dangerous exercises (Figure 2).

Figure 2

Figure 2

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Injury Rate, Onset, Severity, and Treatment

Table 2 provides the injury rates, onset, severity, and treatment for injuries to the 174 injured athletes from the total 213 strongman athletes surveyed. Eighty-two percent of strongman athletes sustained an injury in training or competition in the previous year; 76% received at least one training injury, whereas 31% had at least one competition injury. Subgroup analysis revealed only 2 significant differences in injury rates for strongman athletes injured in competitions. There were significantly more injuries per athlete per year for athletes ≤30 than >30 years (0.5 ± 0.8 vs. 0.3 ± 0.6, p = 0.03) and >105 than ≤105 kg (0.5 ± 0.8 vs. 0.3 ± 0.6, p = 0.014).

Table 2

Table 2

Over two-thirds of injuries for the strongman athletes were acute, with 56% of all injuries having occurred for the first time. Nearly half the injuries were considered to be of moderate severity. Three groups (>30 years, ≤105 kg, and high-level athletes) reported that one-quarter of their injuries were major. Strongman athletes used self-treatment (54%) or requested the assistance of medical professionals (41%) for their injuries. From subgroup analyses of the injured athletes, significant differences in the severity of injuries between the ≤30- and >30-year (χ2² = 9.3, degrees of freedom [df] = 2, p = 0.009) and between the ≤105- and >105-kg (χ²2 = 6.1, df = 2, p = 0.046) athletes were observed. Subgroup analyses of the injured athletes revealed significant differences in the treatment of injuries between the ≤30- and >30-year athletes (χ2² = 6.3, df = 2, p = 0.043) and between the low-level and high-level competition standard (χ2² = 7.1, df = 2, p = 0.029).

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Injury Nature (Body Site and Type)

The lower back, shoulder, bicep, and knee accounted for more than 65% of all injuries (Table 3). Muscle or tendon strains and tears were sustained in 60% of cases.

Table 3

Table 3

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Exercises and Injury Sites

From the strongman athletes' injury data, traditional exercises accounted for just over half of injuries (deadlift 18%, squat 16%, overhead press 9%, bench press 6%, and other 6%) (Table 4). Strongman events accounted for 46% injuries (9% stone work, 8% yoke walk, 6% tire flip, 5% farmer's walk, 4% axle work, 4% log lift and press, 2% circus dumbbell, and 8% other). Injury sites were similar for the traditional exercises and strongman events (lower back 15 and 8%, respectively; shoulder 11 and 10%, respectively; and knee both 5%); however, strongman events were also associated with 9% bicep injuries.

Table 4

Table 4

From the rated perceptions of the 174 injured strongman athletes, 36% believed traditional exercises to be the direct cause of their injury, whereas 25% attributed their injury directly to strongman implement training. Thirty-five percent believed their injuries originated from both strongman implement and traditional training, whereas 4% were unsure of the causative activity.

The greatest injury frequency counts from the 174 injured strongman athletes were for the traditional exercises—the deadlift and squat with lower back injuries (37 injuries), the overhead press and bench press with shoulder injuries (24 injuries), and the squat with knee injuries (11 injuries). There were also high frequency counts for the strongman exercises—the log lift/press and circus dumbbell with shoulder injuries (13 injuries), the tire flip and stone work with bicep injuries (18 injuries), and the stone work with lower back injuries (7 injuries).

Of the total resistance training performed by all 213 strongman athletes, 31% was strongman implement training. However, for the 174 strongman athletes who were injured, when analyses of injuries were conducted to account for exposure to training with traditional or strongman implements, 66% of total injuries resulted from strongman implement training compared with 34% from traditional training. This means that strongman athletes were 1.9 times more likely to sustain injury when performing strongman implement training as compared with traditional training. Whereas 40% of all 213 strongman athletes believed that strongman training carried a greater risk of injury than traditional training, 52% believed the risks of injury were the same for both training approaches.

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Risk Factors for Injury (Load, Time, and Technique)

For the 174 injured strongman athletes, injured strongman athletes sustained 91% of all injuries with heavy loads (70–90% 1RM), with the highest injury occurrence at a load of 90% 1RM (19%). Muscle strains and tears (39%), lower back (31%), and deadlift (26%) were most frequent with a load of 90% 1RM. Injury occurrence was similar with average training loads and competition loads (83 and 86% 1RM, respectively).

Just over half (51%) of training injuries occurred in the general preparation phase. The most common time for injury was “early” in the training session (36%) with shoulder (29%) and muscle strains and tears (33%) most common. The squat accounted for 24% of all the early occurring training session injuries. Of all reoccurring injuries, 57% occurred early in the training session. Forty-four percent of injuries occurred “late” in the competition with biceps (35%) and muscle strains and tears (35%) most common, the stone and deadlift work (car and axle) accounting for 55% of all the late occurring competition injuries.

Nearly a quarter of all strongman athletes believed poor technique was the cause of their injury (Figure 3). Overtraining/overuse, lack of warm-up/staying warm, a preexisting condition/wear and tear, fatigue, or the load being too great contributed to 35% of all injuries.

Figure 3

Figure 3

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Discussion

The results of this exploratory retrospective study provide the first data on the injury epidemiology of strongman athletes. Only 20% injuries in the current study were described as having a major effect (i.e., required a complete cessation of training for a week or more), which was similar to the 22% for powerlifters (19). However, strongman athletes suffered less mild (33%) and more moderate injuries (47%) than powerlifters (both 39%) (19). It seems that similar to powerlifters, injuries obtained by strongman athletes are not overly severe or disabling, requiring only minor or moderate modifications to the regular training program.

In the current study, the >30-year group had almost twice as many major injuries as the ≤30-year group. Morphological and mechanical changes in humans occur with age (24), which may be a reason for a greater rate of severe injuries in the older than younger strongman athletes in the current study. However, such age-related differences were in contrast to results for masters powerlifters (≥40 years) who had comparable injury severity to open-aged powerlifters (19). Such results may therefore reflect sport-specific injuries in loading argued by Keogh (20) who found in a review a number of differences in the injury epidemiology of weightlifters, powerlifters, and bodybuilders.

When the 2 training approaches were equated by exposure time, strongman implement training resulted in almost twice as many injuries as traditional training. Strongman athletes in this study ranked presses, lifts, and carries/walks as the 3 most commonly used strongman movement categories in their training programs. In a recent study (32), strongman competitors (n = 167) reported the farmer's walk (96%), log press (95%), stones (94%), tire flip (82%), axle work (80%), and yoke walk (75%) as the most common strongman implements used in their training programs. These 6 events were listed the top 6 causative strongman exercises in the current study, accounting for 77% of all injuries reported by strongman athletes. Based on the results of Winwood et al. (32), such a result was expected as strongman exercises performed more commonly are likely to contribute to more injuries than exercises performed less frequently. The lack of any significant differences in the training injury rates for the strongman groups differentiated by age, body mass, or competitive standard in this study was comparable with that found in powerlifting for the effect of age, body mass, and gender but not for the effect of competitive standard (19). For further description of the training practices of strongman athletes, readers are referred to Winwood et al. (32).

The 66% acute injuries for all the strongman athletes were slightly higher than the 59% acute injuries for powerlifters (19). However, such percentages must be interpreted with some caution as the present retrospective design and that of Keogh et al. (19) lack medical confirmation. Some injuries may seem acute but could reflect chronic degeneration (3). In the present study, 44% injuries were reported as being repeated injuries, which may further suggest some chronic degeneration as a result of strongman training. Furthermore, strongman athletes may be participating in other physical activities that could potentially either result in injury or contribute to chronic maladaptations to increase the risk of injury during strongman training or competition.

An interesting finding in this study was that the >105-kg group had proportionally less severe and moderate injuries than the ≤105-kg group. This was not expected as it was thought that this group would have more severe injuries because of the heavier loads these athletes train with and encounter in competition. Strongman competitions are generally divided into 2 body mass classes (≤105 and >105 kg): >105-kg-class athletes generally lifting and/or carrying heavier loads than the ≤105-kg class. Thus, the strongman athletes in the >105-kg class are subjecting themselves to greater absolute musculoskeletal stresses than the ≤105-kg athletes, although such loads could be relatively lower relative loads given the greater cross-sectional area of the loading structures. As there is a tolerance load of a certain magnitude in human tissue, increased mechanical loading on the musculoskeletal system can be an inciting factor for injury (20). Older strongmen may have more exposure to resistance and strongman training putting them at increased risk; conversely, they have had a longer time to build up resistance over time, so could be at less risk. Research has demonstrated that world-class powerlifters and world-class strongman athletes can reduce spinal loading with greater loads than athletes with less experience (7,25). Results from the current study and that of previous research (7,19,25) most likely reinforce the importance of training technique and experience on stress reduction to the body and consequently injury reduction.

The lower back, shoulder, bicep, and knee constitute the most commonly injured anatomical areas found in the strongmen. The most commonly injured sites from traditional exercises were, in descending order, the lower back, shoulder, and knee, whereas for the strongman events, this was the shoulder, bicep, and lower back. These results pose the question as to what factors may contribute to these differences in the most commonly injured anatomical locations between traditional and strongman exercises.

Strongman events such as the yoke walk, farmer's walk, and tire flip are total body movements performed in multiple planes that may involve periods of unilateral and bilateral ground contact and require the production of horizontal and vertical ground reaction forces. In contrast, traditional weight training movements used in bodybuilding, powerlifting, and weightlifting events are predominantly bilateral and vertical in nature, requiring the production of predominantly vertical ground reaction forces. As there are subtle-moderate differences in injury epidemiology of powerlifting, weightlifting, and bodybuilding (20), it is likely that strongman training would also have somewhat unique injury risks and epidemiology because of the various types of exercises performed.

In powerlifting (which consists of the squat, deadlift, and bench press), the most common sites of injury were shoulder, lower back, knee, and elbow (2,19,27), whereas the most frequently injured sites in weightlifting (which consists of the snatch and clean and jerk) were the knee, shoulder, lower back, wrist/hand, and elbow (5,27,28). In bodybuilding that uses weight training equipment for training, but not competition, the sites of injury are varied depending on the study; however, in a recent study, the most frequently injured body sites were shoulder, wrist, arm/forearm, elbow joint, and spine (9). The differences in the type and manner in which these exercises were performed in the various sports may explain the differences in injury epidemiology seen in the current study for traditional compared with strongman exercises (20).

The differences in injury sites between traditional training and strongman implement training may reflect the relatively unique stresses that some of these lifts/events place on the body (25). Traditional exercises (deadlift and squat) produce exceedingly large hip extensor torques (1,7,11) and compressive or shear lumbar forces (7,13). Winwood et al. (32) reported that 100% of strongman competitors performed traditional exercises (i.e., squat and deadlift) as part of their training programs; therefore, the large percentage of lower back injuries with these exercises can be expected. We found that strongman athletes commonly incorporated the yoke walk and stone lift into their training programs. The common use and stress associated with these events may increase the risk of injury. High spinal compression loads in the yoke walk have been attributed to the bracing action of the torso musculature to support the yoke load and to offset the deficiencies in hip abduction strength on weight acceptance with the swing leg (25). Lower spinal compression loads associated with the stone lift compared with the yolk walk have been attributed to lifting technique (25), as strongmen curve their torso over the stone, getting the stones' center of mass close to their lower back. Stone lifting may still have quite high spinal injury risk as this technique increases the degree of spinal flexion angles and is associated with very high lower erector spinae activity (second highest after the tire flip) (25).

The shoulder is the most commonly injured anatomical region for powerlifters (2,19) and bodybuilders (9). Many of these shoulder injuries could be attributed to the heavy loads used in upper body pressing exercises like the bench press and shoulder press. These traditional exercises and the strongman implements (axle, log, and circus dumbbell press) produced the highest amount of shoulder injuries in the current study. The risk of shoulder injury may be reduced by performing overhead presses with the hands and elbows anterior to the shoulder with a neutral grip (8,10), as seen in the strongman event, the log press. However, reduced injury risk was not observed in this study, with loading parameters used with these exercises/events maybe a reason (32).

The incidence of bicep injury in the strongman athletes was higher than for weightlifting (27), powerlifting (19,27), and bodybuilding (9). Such results and basic kinesiology analysis of the events like the tire flip and stone work suggest that bicep weakness or fatigue may limit the transfer of force produced from the larger muscle groups about the torso and shoulder and increase bicep injury risk.

Knee injuries accounted for 11% of all injuries, which was similar to 9% for powerlifters (19) but lower than 19% for elite weightlifters (5). Strongman athletes attributed the squat to 42% of knee injuries. The similar percentages of knee injuries between strongman athletes and powerlifters may be because of the back squat being the most commonly performed squat by both groups (32). Weightlifters may be at greater risk of knee injury as exercises like front squats, clean and jerks, and snatches produce greater torque at the knee because of the acute knee angle and/or larger anterior tibial translation (14,20). However, no injury was attributed to lifting by any strongman athlete in our study. Such a result is surprising as nearly 90% of strongman athletes perform lifts or their derivatives as part of their strongman training (32).

Muscle strains and tears (38%) and tendon strains and tears (23%) being common injuries for strongman athletes were also consistent with injury types for weightlifting (5,31) and powerlifting (2,26). Acute bicep tendon injuries have been associated with bodybuilding and the snatch, and acute injuries to the quadriceps and patella tendons have been associated with the squat, clean, jerk, and snatch (22). Tendon injuries are often the result of acute tensile overload and repetitive microtrauma as seen in overuse injuries (23).

To the authors' knowledge, only 2 other studies have investigated inciting events to injury in the weight training sports (9,28). In the present study, 91% of all injuries to strongman athletes occurred with heavy loads (70–90% 1RM). Such a result suggests that injury and load may be highly correlated; however, no significant differences were found between loads (≤70 and ≥90% 1RM) and their effect on injury severity in this study. Injuries with these loads were consistent with the training and competition loads that characterized strongman training (32).

Injuries in bodybuilders (9) have occurred as a result of improper warm-up (42%), too vigorous exercising (35%), or a lack of “guarding assistance” (spotting) (7%). Interestingly, 36% of injured strongman athletes sustained training injuries that occurred early in the training session, a result which may further underscore the importance of adequate warm-up before heavyweight training as performed in sports like strongman.

Technical errors are an important risk factor contributing to 31% of injuries in weightlifters (28). Although strongman athletes cited poor technique (25%) as the most common contributing factor to injury, there seemed to be a greater variety of contributing factors.

Tiredness (fatigue) and excessive overload contributed to 81% of injuries for weightlifters (28), a result considerably higher than the 13% for strongman athletes in our study. Fatigue can incite injury (6,16) by altering motor control strategies and perhaps joint loading. Interestingly, 44% of the strongman athletes in our study sustained injury late in the strongman competition (as compared with 24% that occurred early or 33% that occurred in the middle of the competition), which may indicate that fatigue and/or reduced concentration are contributing factors to competition injuries.

Forty-one percent of strongman athletes in our study consulted qualified health professionals for their injuries, which was higher than 25% for adolescent powerlifters (2) but lower than 57% for powerlifters (19). Interstudy differences in injury management among powerlifters may be because of the differences in age, training experience, and competitive standard (19).

Although strongman may be considered dangerous because of the extreme stresses these athletes place on their bodies, our surveyed strongman athletes suffered a relatively low injury rate (5.5 injuries per 1,000-hour training) compared with National Football League (NFL) athletes (12.7 injuries per 1,000 athlete exposures to NFL practices) (12) but a relatively high rate than the other 3 weight training events of bodybuilding (1.0 injury per 1,000-hour training) (9), powerlifting (1–5 injuries per 1,000-hour training) (2,19,27,29), and weightlifting (3–4 injuries per 1,000-hour training) (5).

The present study sought to collect the full spectrum of epidemiologic data, particularly the variables missing from the current weight training literature (e.g., environmental location, onset, timing, and nature of injury) (20). However, such in-depth analysis using a retrospective design can be problematic (e.g., high numbers of only partially completed questionnaires). Future research should involve the use of a prospective cohort or case-controlled design to minimize such limitations and examine the effect of a variety of independent variables on the injury epidemiology of this sport. Such designs could use a medical examination to increase the validity of the nature of the injury.

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Practical Applications

Strongman athletes and strength and conditioning coaches who use these training methods should follow structured conditioning programs with a periodized approach. Such an approach would help to ensure appropriate loading strategies for training phases and planned exercise progressions to ensure technical competency with these lifts/events. Supplemental training on areas vulnerable to injury with this mode of training may help reduce athletes' injury risk. Appropriate warm-up protocols and the avoidance of overtraining and fatigue may also play a part in reducing injury risk. Strongman athletes and strength and conditioning coaches can use these data as a possible source of new ideas to reduce their risk of injury and improve their training practices.

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Please note that completion of this survey indicates your consent to participate.

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Appendix 1: Retrospective Injury Epidemiology of Strongman Competitors Questionnaire Participant Information Sheet 3/04/12

An Invitation.

Hello strongman competitors. My name is Paul Winwood and I have competed in bodybuilding and powerlifting, and have a passion for resistance training. I invite you to take part in an exciting research project. The survey is called 'Injury epidemiology of strongman competitors'. This survey will form part of my PhD thesis, which is under the guidance of my supervisors: Professor John Cronin and Associate Professor Justin Keogh (National level U105 kg strongman competitor). The aim of this study is to help improve our understanding of the risks and injuries associated with strongman training. The information will benefit strongman athletes and strength and conditioning coaches when prescribing strongman event training to their athletes. We would be very grateful if you could take the time to fill out this survey. Please know that your participation is entirely voluntary and you will not be disadvantaged by not participating.

What is the purpose of this research?

The purpose of this study is a) to describe the injuries associated with strongman training; and b) to provide a basis for injury preventive initiatives for strongman implement training. We will seek to publish a summary of the findings of the study in a scientific journal, like the Journal of Strength and Conditioning Research. This research follows on from our recent published research on the sport of strongman: http://www.ncbi.nlm.nih.gov/pubmed/21993033, http://www.ncbi.nlm.nih.gov/pubmed/22233785

How was I identified and why am I being invited to participate in this research?

You have been identified (through the use of Facebook and the Internet) as a potential participant in this research because you are a strongman competitor, who uses a training diary and have at least twelve months current experience in using common strongman exercises like the tire flip, farmer's walk, log press and sled drags in your training. Only strongman competitors who meet these criteria are eligible to participate in this study.

What will happen in this research?

The on-line survey will take approximately 10 to 20 minutes for you to complete. The questions give you the opportunity to elaborate on your use of strongman implements in your strength and conditioning practice and their injury potential. We would like you to answer as many questions as you can as your knowledge and experience in this field is important to us. We want to learn from your experience. The types of questions you will encounter will include; drop down boxes, check boxes, ranking, and open text questions. You are asked to please select or tick which boxes are relevant. For open text box questions please type your answer in.

What will happen to my data?

An academic publication summarising the study findings will be sought and this study will form part of my doctoral thesis. The study data set will only be used for the purpose for which it has been collected. No individuals will be identified and no individual's answers to any questions will be reported. Only summary data will be reported.

What are the benefits?

This study will be most useful for strongman competitors and strength and conditioning coaches to improve our understanding of the risk factors for injuries and the types of injuries associated with strongman training. Such information will benefit strongman athletes and strength and conditioning coaches when prescribing strongman event training to their athletes.

How will my privacy be protected?

You will complete the survey anonymously as only a participant number will be associated with your answers. The researchers will not be able to identify you as a participant.

What are the costs of participating in this research?

There are no costs to you to participate in this research except for your time.

What opportunity do I have to consider this invitation?

The survey link will be active for a period of three months. During this time you are welcome to consider the invitation to take part in this research.

How do I agree to participate in this research?

By completing the questionnaire you have consented to participate in this research project. This also means that you have read and understood all the information contained in the participant information letter and have clarified any details prior to starting the research project.

Will I receive feedback on the results of this research?

If you would like to view the findings of this research please copy and save the URL address below. You will be able to access the results using this URL address in approximately four months time.

www.sprinz.aut.ac.nz/research-results.

What do I do if I have concerns about this research?

Any concerns regarding the nature of this project should be notified in the first instance to the Project Supervisor, Professor John Cronin, john.cronin@aut.ac.nz, Ph 921 9999 ext 7523.

Concerns regarding the conduct of the research should be notified to the Executive Secretary, AUTEC, Dr Rosemary Godbold, rosemary.godbold@aut.ac.nz, 921 9999 ext 6902.

Whom do I contact for further information about this research?

Researcher Contact Details:

Paul Winwood, Bay of Plenty Polytechnic, School of Applied Sciences, Tauranga, New Zealand paul.winwood@boppoly.ac.nz.

Project Supervisor Contact Details:

Professor John Cronin, Sport Performance Research Institute New Zealand, School of Sport and Recreation, AUT University, Auckland, New Zealand.

This research was approved by the Auckland University of Technology Ethics Committee on 21st February 2012, AUTEC Reference number 12/26.

Section 1: Demographics.

  • 1) What is your gender?
  • 2) What is your age? (years)
  • 3) What is your height (cm)?
  • 4) What is your body mass (kg)?
  • 5) What is your country of origin?
  • 6) How many years of general resistance training experience do you have?
  • 7) How many years of strongman implement training experience do you have?
  • 8) How many years have you been competing in the sport of strongman?
  • 9) What is the highest level of strongman competition you have competed at?

Section 2: Training.

Please refer to the whole year of training (i.e. all of 2011) and please use your training diary when answering the questions in this survey.

  • 10) How many resistance training sessions (on average) did you generally perform each week in the past year? Questions 10 to 13 refer to all aspects of your yearly training phases i.e. general preparation phase, specific preparation phase, competition phase, and post competition. Please note that resistance training refers to all types of training with any resistance i.e. traditional (e.g. squat and bench press) and strongman implement training (e.g. farmer's walk and tire flip)
  • 11) How long (on average) would each of your resistance training session be to the nearest 15 minutes?
  • 12) How many training sessions (on average) did you generally perform each week using strongman implements?
  • 13) What percentage (on average) of your overall training consists of strongman implement training? Think about % of sets per resistance training session over a week.
  • 14) Rank the type of strongman events that you use (1 being most commonly performed to 6 being least performed). If you don't perform all types of events just rank the ones you do use.
    • _______Carries and Walks (e.g. Farmer's, Yoke, Duck, Conan's wheel, shield, kegs, and frame)
    • _______Drags and Pulls (e.g. Truck, sleds, arm over arm, ropes and chains)
    • _______Presses (e.g. Log, Viking, axle and dumbbells)
    • _______Lifts (e.g. Stone, Tire flip, Safe, kettle bells and car deadlift or squat)
    • _______Grip exercises (e.g. block, hand and tools).
    • _______Holds (e.g. crucifix)
  • 15) Rank what strongman implements you commonly incorporate into your training (Top being most commonly performed to bottom being least performed). If you don't perform all types of events just put in the ones you do use.
    • _______Farmer's Walk bars.
    • _______Steel Logs.
    • _______Sand Bags.
    • _______Sled Pulling/Pushing.
    • _______Yoke walk implements.
    • _______Conans wheel/tools for heavy carrying.
    • _______Ropes.
    • _______Kettle bells.
    • _______Tyres.
    • _______Stones.
    • _______Kegs.
    • _______Axles.
    • _______Blocks/tools for grip exercises.
    • _______Crucifix/tools for holds.
    • _______Chains.
    • _______Cars/frames.
    • _______Duck walk implements.
    • _______Viking press implements.

Section 3: Previous Injury.

For the purposes of this study, the term “injury” will be defined as any physical damage to a body part that caused you to miss or modify one or more training sessions or competitions. Please keep this definition in mind when answering the questions.

You will need to refer to the past year of training (i.e. all of 2011) when answering these questions. Please refer to your training diary when answering the questions as this will help to eliminate recall bias.

  • 16) How many training injuries (i.e. injuries that occurred during training sessions) did you suffer from in the LAST YEAR that affected your training ? (Note: This question refers to training only and not competition injuries which the next question covers).
    • Answer Range: None to >10.
  • 17) How many competition injuries (i.e. injuries that occured during competition) did you suffer from in the LAST YEAR that affected your training? (Note: This question refers to competition only and not training injuries which the previous question covered).
    • Answer Range: None to >10.
  • 18) In regard to any injury/s you received in the last year. Were your injury/injuries a direct result of training with strongman implements (i.e. farmer's walk and tire flip) or traditional exercises (i.e. squat and bench press), both or are you unsure?
    • [] Strongman Implements.
    • [] Traditional Exercises.
    • [] Strongman implements and traditional exercises.
    • [] Unsure.
    • [] I had no injuries.
  • 19) What traditional exercises or strongman events were you performing when you suffered the injury? Please state what part of the body was injured, the injury type and what type of exercise/event you were performing e.g. front squat, stone lift, tricep extension. Please also answer the other questions pertinent to that injury.
    • Injury site 1?
      • () Shoulder.
      • () Neck.
      • () Upper back.
      • () Elbow.
      • () Hip/buttock.
      • () Knee.
      • () Groin.
      • () Chest.
      • () Lower back.
      • () Tricep
      • () Quadricep
      • () Bicep
      • () Hamstring.
    • Injury Type?
      • () Unsure.
      • () Bruise.
      • () Laceration/Cut.
      • () Muscle Strain/Tear.
      • () Tendon Strain/Tear.
      • () Ligament Sprain/Tear.
      • () Cartilage Damage.
      • () Bone Fracture/break.
      • () Other.

What traditional exercise or strongman event were you performing that resulted in the injury?__________________________________________

What type of surface or terrain were you performing the exercise on?

  • () Grass.
  • () Concrete.
  • () Asphalt.
  • () Carpet.
  • () Wooden floor.
  • () Astroturf (artificial grass)
  • () Other.

What time of day (approximately) did the injury occur?

Range: 01:00 to 24:00.

Approximate Load (as a % of 1RM) you were doing?

Range: 5 to 100.

Did the injury occur in your General preparation phase, Specific preparation phase, Pre-competition phase, during competition or post competition?

  • () General preparation phase.
  • () Specific preparation phase.
  • () Pre-competition phase.
  • () During competition.
  • () Post competition.

At which part of the training session or competition did the injury occur (i.e. early, mid or late)?

  • () Early in the training session.
  • () Middle of the training session.
  • () Late in the training session.
  • () Early in the competition.
  • () Middle of the competition.
  • () Late in the competition.

What do you think was the reason for your injury? i.e. poor technique, faulty equipment etc: ____________________________________________

How did this injury affect your training?

  • () Small alteration (i.e. changed your performance of an exercise)
  • () Large alteration (i.e. stopped you from performing an exercise)
  • () Stopped (i.e. stopped your training completely)

Did this injury occur suddenly (just happened) or did it gradually become worse over time?

  • () Suddenly (i.e. No warning, injury was felt at a particular time)
  • () Gradually (i.e. Soreness or stiffness became gradually worse over time)

Is this the first time you have had this injury or is it a repeated injury (i.e. multiple back sprain)?

  • () First time.
  • () Repeated.

What type of treatment was used to manage the injury?

  • () None.
  • () Self-administered (e.g. ice, liniment, strapping, etc)
  • () Medical (e.g. doctor, physiotherapist, chiropractor, etc)

What safety equipment were you wearing when the injury occured?

  • [] None.
  • [] Wrist straps.
  • [] Elbow wraps.
  • [] Knee wraps.
  • [] Weight belt.
  • [] Lifting suit.
  • 20) Have you had a 2nd injury in the past year?
    • () yes (Question 19 and 20 repeated until answer was no - up to 10 injuries could be reported)
    • () no.

Section 4:Additional information.

  • 38) Based on your experiences training with using strongman implements; how have you found this mode of training in regard to injury risk compared to traditional modes of training?
    • () Strongman implement training carries a greater risk of injury than traditional training.
    • () Strongman implement training carries the same risk of injury as traditional training.
    • () Strongman implement training carries less risk of injury than traditional training.

Please explain your answer.

_____________________________________________________________________________________________

  • 39) Please rank what you believe is the most dangerous strongman event to the least dangerous event in terms of injury risk.
    • _______Farmer's Walk.
    • _______Log clean and press.
    • _______Heavy Sled Pulling/Pushing.
    • _______Yoke Walk.
    • _______Duck walk.
    • _______Conans wheel.
    • _______Tire flip.
    • _______Stone lift.
    • _______Keg toss.
    • _______Chain drag.
    • _______Cars/frames for heavy deadlifts.
    • _______Cars/frames for heavy carrying.
    • _______Other.
    • If you chose other, please specify ______________________________________
  • 40) Is there anything that you wish to add?
    • ___________________________________________________________________________

Thank You! Your response is very important to us.

Keywords:

injuries; strength and conditioning; weight training; resistance training

Copyright © 2014 by the National Strength & Conditioning Association.