Injuries to athletes are a common occurrence in the sporting arena. Elite athletes are expected to perform consistently at the highest level, subjecting their bodies to excessive forces, stresses and impacts, which without adequate preparation can result in frustrating mid-season breakdowns or entire seasons on the sideline.
While injuries in the elite sporting landscape are wide-ranging, it’s unlikely to surprise our readers that the occurrence, frequency and impact of hamstring strain injuries are extremely high across many sports. Hamstring strain injuries are in fact one of the most frequent non-contact injuries that occur in all high-speed running-based sports1. The analysis of seasonal injury reports continue to confirm the high rate of hamstring strain injuries, including:
- The NFL recording 96 incidences of hamstring strain injuries in the 2014 season, placing it third behind knee and ankle injuries in the NFL2;
- The NCAA recording 1,142 reported hamstring strain injuries during the 2009/10 to 2013/14 academic years3;
- The Australian Football League 2013 injury report stated that hamstring strain injuries were the number one injury in the game in terms of both incidence and prevalence (missed games)4;
- The Australian Football League 2014 injury report indicating that although the overall rate of hamstring injuries at clubs had decreased it was still number one in terms of new injuries per club per season (5.2 hamstring injuries per club per year)5; and
The perplexing thing is, as noted recently in the British Journal of Sports Medicine6:
In spite of all the research and additional understanding of hamstring muscle injuries over the past 20-30 years, we have not reduced the incidence of first-time injuries, and the recurrence rate is still extremely high.
With powerful research providing a much clearer understand of why hamstring strain injuries occur, it begs the question: why does the occurrence of hamstring strain injuries remain so high? Is it that elite sporting organisations are failing to learn, innovative and challenge the status quo? Are organisations taking too much of a reactive approach to injuries and failing to implement preventative measures? Or is something else at play?
What Have We Learned?
One of the biggest learnings in recent years is the effect of eccentric hamstring strength on the occurrence of hamstring strain injuries.
Ground-breaking research on the link came from a group of sports scientists from Australia with one key goal – to discover why hamstring injuries continued to be so prevalent in one of Australia’s most popular sports – Aussie Rules Football. Aussie Rules Football involves two teams of 18 on-field players competing to score points against each other by kicking a ball through their opposing team’s posts at each end of the oval-shaped field. Athletes in the top professional league (the AFL) in Australia play for 80 minutes and commonly run more than 10 miles in each game.
With support from AFL teams desperate to reduce their hamstring strain injury rates, the scientists (primarily Dr Anthony Shield and Dr David Opar) were able to collect comprehensive data by measuring athletes’ eccentric hamstring strength during the age-old Nordic Curl exercise in the 2013 pre-season period. That data was then compared against injury data compiled throughout the 2013 season, with some very interesting results.
Those results indicated that players who finished the pre-season with relatively low eccentric hamstring strength were more likely to have a hamstring strain injury. As a statistical cut point, players with eccentric hamstring strength below 279 newtons (roughly 63lbs of force) were 4.3 times more likely to have a hamstring injury in the upcoming season than their peers above 279 newtons.
The report also demonstrated that, to a large degree, the heightened hamstring injury risk caused by age7 could be largely overcome by increases in eccentric strength, as demonstrated by the below chart:
Using eccentric hamstring strength as an example, it is clear from the above graph that although unlikely to eradicate the occurrence of hamstring strain injuries in elite sport, it is possible to mitigate the occurrence and severity of injuries by utilising tools that provide objective measurements that can translate into science-backed risk matrices.
How to Measure Hamstring Strength?
The age of objective metrics and big data has well and truly hit the industry, and while not all metrics are created equal, new technologies – and a better understanding of their applications – are providing sporting teams with more and more actionable data every day.
Armed with objective data, preparation staff can identify at-risk athletes and take steps in their program design to address identified risks for specific players (such as putting them in a dedicated pre-hab program to build strength in the affected hamstring(s)). For years, we have heard the adage that programs should be tailored to the athletes’ unique requirements, but quite often this isn’t carried through in practice. The first step, of course, is to get the objective data in the hands of preparation staff.
Typically objective data on eccentric hamstring strength was procured by (at the gold standard) subjecting athletes to a 20-minute test on an isokinetic dynamometer. Testing by this method has few supporters in the elite sporting environment given the exorbitant cost of an isokinetic dynamometer, the time cost required to test players, the highly technical nature of the device and concerns of athlete soreness at the conclusion of testing. At the other end of the scale, handheld dynamometers offered a relatively cheaper alternative, but user error accounts for considerable discrepancy in data collection.
Fortunately, the elite and sub-elite sporting industry is far from immune to the onset of innovation and digital disruption. The significant gap between the isokinetic and handheld dynamometers has been filled by the NordBord – the next generation of diagnostic technology focused on arming strength and conditioning teams with a tool that can quickly, accurately and cost-effectively provide metrics that actually matter.
It was from Dr Anthony Shield and Dr David Opar’s study into the AFL that identified the need for the NordBord. Clubs wouldn’t allow their players to be consumed for extended periods on an isokinetic dynamometer and data from handheld devices would be too inconsistent. Accordingly, they developed their own field-testing device.
The NordBord embodies an innovative design with simplistic elegance and has been designed with familiarity, practicality and ease of use at mind. The device is relatively simple to use – players kneel on the NordBord and perform repetitions of the Nordic Curl exercise while the NordBord calculates (amongst other things) the peak eccentric hamstring strength of each leg independently.
In less than 2 minutes on the device (once familiarised), preparation staff will have an indication of the athlete’s eccentric hamstring strength and between-leg symmetry. Then they can determine, by reference to the risk matrixes generated by Dr. Shield and Dr. Opar’s research, which athletes fall into the at-risk category. From there, they can customise pre-season routines to improve these figures into a safer ranges. The ability to benchmark and then retest ensures that the athlete only moves onto a full load when they are ready.
The NordBord empowers strength and condition professionals with real-time, quantifiable and objective data.
It is important to note that although the NordBord provides a specific figure that can be benchmarked, each athlete’s age and hamstring injury history must also be taken into account. But while these risk factors are non-modifiable in themselves, the effect these variables have on the propensity for injury can be reduced with an increase in eccentric hamstring strength (as demonstrated in the graph above, athletes in their late twenties can reduce their injury probability to levels comparable with their 18-year-old counterparts).
Metrics and data will drive elite athlete management and elite sporting clubs that fail to innovate will fall behind. Quick and efficient access to real-time metrics is why the NordBord should form a part of any elite sporting organisation’s screening and monitoring routine.
Tom Myslinski, Head Strength and Conditioning Coach at Jacksonville Jaguars, said the NordBord has given him “the ability to identify and address those at-risk athletes” on their roster.
“Hamstring strains can keep key players out of action for weeks so being able to determine which players are at risk, and do the correct work to avoid future injury in those players, is invaluable for us,” he said.
The NordBord is not limited to eccentric hamstring strength, and can also measure an athlete’s isometric strength. While research may less support isometric strength as a predictor or injury, it is undeniably a useful and low-impact alternative. This makes it ideal for testing players who are particularly weak or fragile, such as those returning from injury. Long have handheld dynamometers been used to measure isometric strength, with extremely variable results due to operator error. The NordBord instead removes the extra human factor and provides a stable, reliable platform for measuring isometric strength.
Incremental improvements are often overlooked during the preseason, but even small improvements can have major impacts towards the end of a season. The NordBord is equipped to detect these subtle changes, allowing them to be actioned upon when players are most malleable.
“… to determine which players are at risk, and do the correct work to avoid future injury in those players, is invaluable for us.” — Tom Myslinski, Head Strength and Conditioning Coach, Jacksonville Jaguars
Ultimately, it is in the interest of high performance and conditioning staff to take these proactive steps. Even a single injury prevented can save days or weeks where their attention is pulled away from their primary function: helping athletes win.
Proactive injury management can be easy, and with the proliferation of technology in the athlete management sector and athlete data amalgamators such as Kinduct, CoachMePlus and Kitman Labs, the NordBord becomes a high-value string that can easily be added to any team’s bow. Sporting organisations who are prepared to be innovative and dynamic have the opportunity to improve incrementally and measurably over time. Metrics and big data are here to stay, and metrics that matter can go a long way to reducing the occurrence of hamstring injuries in elite athletes.
The Far-reaching Implications of Hamstring Injuries
The implications of hamstring strains are far reaching, and go beyond lost game time for injured athletes. Even the psychological effects on injured athletes cannot be overlooked, especially when recurrent injuries can often plague athletes for their entire professional careers. Even once a player has completed the often lengthy rehabilitation process, confidence to perform in a high-pressure game environment is often reduced, and even a small reduction in performance or decision-making ability can have a massive impact on the outcome of a match. Player welfare is (or at least should be) the primary concern for all elite sporting organisations, so ensuring the implementation of the latest technology, data and injury prevention methods is crucial.
If we continue to explore the fallout from injury occurrences, support staff will echo the grievances of players, with huge amounts of time and effort required to successfully rehabilitate a player for the rigours of elite sport. And with these significant investments of time, the staff’s ability to manage the rest of the team can be adversely affected. Culturally, elite athletes are often known for their egos, but also for their expectations, and organizations with high rates of injury will often find it difficult to attract and retain players, as well as support staff. And with enough injury naturally comes declines in performance. And without drawing too long a bow, eventually these cultural and performance slips can have a negative impact on the financial viability of an organisation – as can salaries paid to an injured player who sits on the bench week after week, willing but unable to contribute.
If you could accurately and cost effectively test an athlete’s hamstring strength in under two minutes, would you? Well, you should certainly consider it.
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- Opar, D.A., J. Drezner, A. Shield, M. Williams, D. Webner, B. Sennett, R. Kapur, M. Cohen, J. Ulager, and A. Cafengiu, Acute Hamstring Strain Injury in Track‐and‐Field Athletes: A 3‐Year Observational Study at the Penn Relay Carnival. Scandinavian Journal of Medicine & Science in Sports, 2014. 24(4): p. e254-e259; Ekstrand, J., M. Hägglund, and M. Waldén, Injury Incidence and Injury Patterns in Professional Football: The Uefa Injury Study. British Journal of Sports Medicine, 2011. 45(7): p. 553-558; Elliott, M.C., B. Zarins, J.W. Powell, and C.D. Kenyon, Hamstring Muscle Strains in Professional Football Players a 10-Year Review. The American Journal of Sports Medicine, 2011. 39(4): p. 843-850.
- NFL Player Injuries
- Epidemiology of Hamstring Strains in 25 NCAA Sports in the 2009-2010 to 2013-2014 Academic Years, Sara L. Dalton, Zachery Y. Kerr and Thomas P. Dompier. Am J Sports Med
- Australian Football League Injury Report 2013
- 2014 AFL Injury Report
- Hamstring Injuries: Prevention and Treatment
- Arnason A, Sigurdsson SB, Gudmundsson A, et al. Risk factors for injuries in football. Am J Sports Med. 2004; 32 (1 Suppl.) 5S-16S.