Category: Injury Prevention

The string that gets pulled too often: the hamstring

by Tim Klein

Have you ever watched an athlete pull up, holding the back of their thigh, with an agonising look on their face? Some of you may have even thought to yourself: “there goes his/her hamstring.”

Well you are not alone. Scientists have also taken notice of the menace that are acute hamstring injuries and are devising methods to prevent the very scenario described above. In soccer players, hamstring muscle injuries are responsible for 12-16% of all injuries1 – with an injury occurring every 1000 hours of exposure (during the match or training)2. Hamstring injuries are particularly nasty because they have a habit of coming back (a group of Danish athletes showed they have 25% chance re-injuring it the following season)3. The question then remains, how to reduce the risk of these injuries? Well, a logical answer might be to strengthen the muscle, but which exercises work best?

Peterson and colleagues4 set out to test if eccentric strengthening of the hamstring, using an exercise called the ‘Nordic hamstring exercise’, can protect the hamstrings from new and/or recurring hamstring injuries.

They looked at 50 Danish soccer teams that were in two groups: Control and Intervention. The difference being that the intervention group were given a 10-week program of the Nordic hamstring exercise. The injury occurrences were then tracked over the next 12 months.

They found that the Nordic hamstring exercise program reduced the injury rate of new injuries (i.e. not reported in the 12 months prior to the study) by 60% and the injury rate of recurring injuries by a whopping 85%! These results suggest that this simple, time- and user-friendly exercise could be used to subdue the menace of hamstring injuries.

The study looked at soccer players, but one could argue that these findings can be carried over to any sport involving running. These types of injuries often occur while running and not necessarily during a sports-specific movement. It could then be suggested that the eccentric strengthening of the hamstring could help keep these nasty injuries at bay in any sport that involves running or sprinting.

This all sounds amazing, but it is important to consider some factors that this study did not do. Firstly, this study was open (i.e. all the teams – including the control – knew the aims of the study). This could have led to bias in reporting or training. Secondly, the authors did not record compliance to the program after the first 10-week period. This means that there was no way of knowing what sessions the teams did. For example, they could have used other eccentric strengthening exercises. This means that the Nordic hamstring exercise may not be the wonder-exercise it is made out to be.

However, a recent review by van Dyk and colleagues5 showed that including the Nordic hamstring exercise in injury prevention programs can reduce hamstring injuries by up to 51%.

To conclude, the Nordic hamstring exercise seems effective in preventing hamstring injuries. It is simple, cost-effective and would be easy to add to a team workout regimen. Like with any new exercise, it should be eased into the program to reduce stiffness the following morning. It seems a viable option to make that darn string harder to pull.


References: 

  1. Arnason, A., Sigurdsson, S.B., Gudmundsson, A., Holme, I., Engebretsen, L. and Bahr, R., 2004. Risk factors for injuries in football. The American journal of sports medicine32(1_suppl), pp.5-16.
  2. Ekstrand, J., Hägglund, M., Kristenson, K., Magnusson, H. and Waldén, M., 2013. Fewer ligament injuries but no preventive effect on muscle injuries and severe injuries: an 11-year follow-up of the UEFA Champions League injury study. Br J Sports Med47(12), pp.732-737.
  3. Petersen, J., Thorborg, K., Nielsen, M.B. and Hølmich, P., 2010. Acute hamstring injuries in Danish elite football: a 12‐month prospective registration study among 374 players. Scandinavian journal of medicine & science in sports20(4), pp.588-592.
  4. Petersen, J., Thorborg, K., Nielsen, M.B., Budtz-Jørgensen, E. and Hölmich, P., 2011. Preventive effect of eccentric training on acute hamstring injuries in men’s soccer: a cluster-randomized controlled trial. The American journal of sports medicine39(11), pp.2296-2303.
  5. van Dyk, N., Behan, F.P. and Whiteley, R., 2019. Including the Nordic hamstring exercise in injury prevention programmes halves the rate of hamstring injuries: a systematic review and meta-analysis of 8459 athletes. British journal of sports medicine53(21), pp.1362-1370.

The Translating Research into Injury Prevention Practice Framework (TRIPP)

by Taron van der Berg

As knowledge about obesity and type-two diabetes increases; more and more people have started making better choices regarding their health and fitness. Many people are going to the gym and playing sport to stay fit and healthy. Unfortunately, this can lead to more injuries amongst the population. Injuries are particularly bad amid professional athletes as their training intensity is much higher and more frequent. According to Sean Williams and his colleagues, the incidence of rugby injuries is 81 per 1,000 player-hours in senior men’s’ professional rugby union matches. The higher the level that at which rugby players compete, the greater the incidence of injury during matches (Williams, S., Trewartha, G., Kemp, S. and Stokes, K., 2013.). One way to develop injury prevention strategies is to study how the injury occurs.

Professor Caroline Finch describes a model, known as the Translating Research into Injury Prevention Practice framework (TRIPP), on how to transform research on injury into real-world injury prevention applications (Finch, C., 2006).

The TRIPP model has 6 stages which can be briefly summarised as:

  1. Injury surveillance
  2. Establish aetiology and mechanisms of the injury.
  3. Develop preventative measures
  4. Evaluate the preventative measure in ideal conditions/scientific evaluation
  5. Describe intervention context to inform implementation strategies
  6. Evaluate effectiveness of preventative measures in implementation context

 

An example of researchers applying the TRIPP model is a study done at the University of Cape Town (Burger, N., Lambert, M., Viljoen, W., Brown, J., Readhead, C., den Hollander, S. and Hendricks, S., 2016). Dr Nicholas Burger and his associates looked at tackle related injuries in under 18 youth rugby players during the the Craven week rugby tournament. Injury surveillance along with video footage of matches were captured for three years. This combination of injury surveillance and video allowed Burger et al. (2016) to classify tackle injuries and to observe why, how and when they occurred.

The main research findings are as follows : – 

Firstly, injury risk was higher in the third and fourth quarter compared to the first quarter, most likely due to fatigue. Secondly, players were less likely to be injured if they were aware of the arriving contact. Finally, tacklers were less likely to be injured when performing shoulder tackles rather than arm tackles.

To prevent tackle injuries in the future, especially in youth athletes, Burger et al. (2016) suggested implementing recovery strategies between matches, teaching safe and effective training techniques and improve the physical conditioning of players to counter the negative effects of fatigue. This study used a sample of high level under 18 players, further research is required at the senior and professional levels.

References:

Burger, N., Lambert, M., Viljoen, W., Brown, J., Readhead, C., den Hollander, S. and Hendricks, S., 2016. Mechanisms and Factors Associated with Tackle-Related Injuries in South African Youth Rugby Union Players. The American Journal of Sports Medicine, 45(2), pp.278-285.

Finch, C., 2006. A new framework for research leading to sports injury prevention. Journal of Science and Medicine in Sport, 9(1-2), pp.3-9.

Williams, S., Trewartha, G., Kemp, S. and Stokes, K., 2013. A Meta-Analysis of Injuries in Senior Men’s Professional Rugby Union. Sports Medicine, 43(10), pp.1043-1055.