Why hamstring eccentrics are hamstring essentials.

There is no dispute that acute hamstring injury is a major sports injury, 1–6 particularly in football codes 2 3 5 6 and other sports that demand high-speed running. 1 The purpose of this editorial is to provide the reader with evidence-based tips for optimising hamstring injury prevention. Early return to sport (≤3 weeks) is often proposed for hamstring injuries, 7 even though basic research clearly shows that ongoing muscle regeneration still occurs, 8 and the risk of recurrence is dramatically increased at this point. 7 Recurrence includes possible additional injury and non-optimal healing of the hamstring muscle-tendinous complex. 9 Such an injury can cause an athlete severe hamstring problems up to a year. 6 10 Therefore, to manage hamstring injuries properly, it is important to address one of the main problems – the extremely high recurrence rate 5 6 7 – which includes everything from exacerbation to re-injury. 11 The acute hamstring injury and its recovery can be diffi cult for most lay people (including athletes and coaches) to comprehend, as jogging and moderate-paced running is often possible early after the injury – suggesting that full recovery is close. However, because the eccentric capacity (the ability to dissipate forces through lengthening contractions) of the hamstring muscle-tendinous complex is not challenged until the introduction of high-paced running, 12 13 full recovery can still be weeks/months away. My own experience is that athletes, coaches and medical personnel are often overoptimistic in their evaluation of when the athlete should return after a hamstring injury. The classic example is the principle often applied in soccer, where a player is deemed ready to play if he can fully participate in the last training session the day or two before a game. This is not a good criterion for return to sport for a soccer player with a recent hamstring injury as match play has 15 times the risk of injury as does a training session. 6 Important factors, such as high-speed running, muscle fatigue and competitiveness are not tested as much in a training session that often consists of small-sided games and more specifi c soccer drills. Askling et al's 14 important work also highlights the problem of a very early return to sport. Isometric hamstring muscle strength in sprinters was 70% (2 weeks), 85% (3 weeks) and 90% (6 weeks) that of the uninjured limb after an initial hamstring muscle injury. The actual …