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Sprint versus isolated eccentric training: Comparative effects on hamstring architecture and performance in soccer players
- Both sprinting and Nordics added to usual soccer practice induced increases in the fascicle length of the biceps femoris long head.
- However, only sprint training was able to both provide the preventative stimulus (increase fascicle length) while also improving sprint performance and mechanics.
- Exposure to sprinting should form part of strategies to both prevent and treat hamstring injuries.
BACKGROUND & OBJECTIVE
It is still commonly accepted that most hamstring injuries in football occur during high speed running (sprinting) activities (1). Hamstring-focused strength training has been proposed in the literature to improve sprint performance in football (soccer) players (2). Specifically, repeated exposure to lengthening hamstring contractions through the Nordic hamstring exercise (NHE) seems to be effective in protecting hamstring muscles from injury in football (3). The relationship between improvements in single joint hamstring strength and sprint performance and mechanics remains uncertain.
Given the effectiveness of the predominantly eccentric NHE in increasing eccentric hamstring strength when added to soccer training, it is important to understand the impact of this single exercise on hamstring muscle architecture when performed in a real football environment.
The aim of this study was to “compare the effects of NHE strength training versus sprint training (programmed as complements to regular football practice) on sprint performance and its mechanical underpinnings, as well as hamstring muscle architecture”.
Sprint training was able to both provide the preventative stimulus (increase fascicle length) while also improving sprint performance and mechanics.
Soccer players were recruited from two different elite soccer teams in Portugal. In this prospective interventional controlled study, sprint performance, mechanics and biceps femoris long head (BFlh) architecture variables were measured before and after six weeks of training during the first six pre-season weeks; in three different groups of soccer players. The “Soccer group” (controls) continued their usual soccer practice, the “Nordic group” players performed a NHE program in addition to usual soccer practice, and the “Sprint group” performed a comprehensive sprint acceleration program in addition to usual soccer practice.
For sprint performance, small to large improvements were reported in the “Sprint group” (excluding maximal velocity), whereas ONLY small negative changes were reported in “Soccer group” and “Nordic group”.
The “Sprint” group showed moderate increase in fascicle length compared to a smaller increase for the “Nordic” group with trivial changes for the “Soccer group”. Only the “Nordic” group presented small increases in pennation angle.
Collectively, the results suggest that both sprinting and Nordics added to usual soccer practice induced increases in the fascicle length of the BFlh; with the sprint showing moderately superior adaptations (16%) compared to the NHE (7%). See Figure 1 for a summary of results.
- Internal and external training load variables were not thoroughly measured and may have confounded the overall effect, specifically fascicle length adaptation.
- The use of two-dimensional ultrasound to estimate fascicle length has some associated methodological limitations mainly derived from a reduced field of view.
- No objective measure of strength change was performed.
- Nine players (28%) dropped out from the study: two from the “Soccer group”; five from the “Nordic group”; and two from the “Sprint group”.
The results of this study suggest that sprint training is superior to NHE to increase hamstring muscle architecture, specifically biceps femoris long head fascicle length; although both groups had a greater improvement compared to regular football training. However, sprint training was able to both provide the preventative stimulus (increase fascicle length) while also improving sprint performance and mechanics.
Adding a sprint-focused programme to regular football training induced greater increases in biceps femoris fascicle length as a complementary intervention during the first six weeks of a preseason period, compared with soccer practice alone. The NHE has previously been linked to sprint performance improvements as well (Ishoi). Therefore, both sprint training and the NHE may provide a potentially preventative stimulus (increase fascicle length), and at the same time induce better sprint performance outcomes. This provides the practitioner with two practical “win-win” strategies. Nothing provides greater muscle activity stimulus to the hamstring muscle group than sprinting (4), and in light of the results presented in this study, exposure to sprinting should form part of strategies to both prevent and treat hamstring injuries.
[Mendiguchia J et al. (2020) Sprint versus isolated eccentric training: Comparative effects on hamstring architecture and performance in soccer players. PloS one, 15(2), e0228283.]()
- Arnason, A., Andersen, T. E., Holme, I., Engebretsen, L., & Bahr, R. (2008). Prevention of hamstring strains in elite soccer: an intervention study. Scandinavian journal of medicine & science in sports, 18(1), 40-48.
- Ishøi, L., Hölmich, P., Aagaard, P., Thorborg, K., Bandholm, T., & Serner, A. (2018). Effects of the Nordic Hamstring exercise on sprint capacity in male football players: a randomized controlled trial. Journal of sports sciences, 36(14), 1663-1672.
- van Dyk, N., Behan, F. P., & 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 medicine, 53(21), 1362-1370.
- van den Tillaar, R., Solheim, J. A. B., & Bencke, J. (2017). Comparison of hamstring muscle activation during high-speed running and various hamstring strengthening exercises. International journal of sports physical therapy, 12(5), 718.