What factors are involved in hamstrings injury?
Hamstrings injury is the most frequent muscle injury in sports that require high speeds, such as football, rugby or American football.
Facilitating proper recovery after training sessions is essential to improve the athlete’s performance, as it allows us to shorten rest times between sessions and increase workload in subsequent sessions. There are several strategies to accelerate recovery, ranging from nutritional strategies (for example, taking supplements) to physical strategies such as massages, active recovery or applying cold therapy. The latter of these strategies is, in fact, one of the most popular nowadays in team sports, and it is common to see top-level athletes submerged in ice baths following a game or an intense training session.
This method is used on the basis that the application of cold reduces the perception of pain, as it can reduce the speed of nerve conduction and blood flow to working muscles, thus limiting the processes of inflammation and swelling. Indeed, there is some evidence to support the effectiveness of this method. For example, a meta-analysis(Leeder, Gissane, van Someren, Gregson, & Howatson, 2012)published in the prestigious British Journal of Sports Medicine, showed that the application of cold after exercise reduced the perception of muscle pain and the levels of creatine kinase in the blood (a muscle damage marker). Furthermore, the authors observed a trend in improved muscle function recovery. Therefore, the application of a cold therapy post-exercise can be an efficient strategy for alleviating fatigue and muscle pain, in the short-term, following intense exercise.
However, the inflammation that accompanies exercise is a process that in the right amount can be beneficial. It activates a series of cellular mechanisms that promote adaptations to training (e.g. muscle hypertrophy, increased number of mitochondria, etc.). By blocking the inflammation with the application of cold post-exercise therapy, we would be impeding these adaptive mechanisms to take place (McPhee & Lightfoot, 2017). Recent studies have shown that applying cold, partly reduces the adaptation to training. For example, in a study(Roberts et al., 2015)which compared athletes who trained for 12 weeks and who, following each session, recovered by applying a cold therapy (10 minutes at 10 degrees) with those who took part in an active recovery activity (10 minutes of light pedalling), the authors observed a lower gain in muscle mass (3 times lower) when the participants recovered with the cold therapy application. In addition, the group that took part in active recovery gained almost double the strength of the group that recovered by immersion in cold water. Furthermore, the results showed that applying cold following an exercise session reduced the anabolic and myogenic response, in other words, it reduced the adaptation processes of the muscle fibres.
Applying a cold therapy following exercise may be advisable, therefore, when the objective is to avoid muscle pain and to mitigate performance loss without affecting the adaptations produced from that session. An example would be to recover from two games that have taken place in a short time period. However, this strategy appears to hinder muscular adaptation to the exercise, and its general inclusion in the plan would therefore not be advisable if the objective is to improve long-term performance. On the other hand, recent evidence has shown that the application of heat (38ºC) maybe even more effective than cold in improving post-exercise recovery, mitigating performance loss and accelerating the re-synthesis of glycogen(Cheng et al., 2017). Moreover, studies on animals suggest that the application of heat after exercise could even increase the adaptation produced with training, especially those related to resistance (e.g. improved mitochondria function)(Tamura et al., 2014). Although the evidence until now has been promising, more studies are needed to be carried out before being able to recommend heat therapy as a recovery strategy.
Cold therapies can help reduce the feeling of muscle pain and mitigate reduced performance following a session or intense game, thus accelerating recovery. However, it is important to bear in mind that this strategy also reduces the adaptations induced by training, and may, therefore, involve minor improvements in performance in the long-term. On the other hand, the benefits that the application of heat post-exercise may provide, both in terms of recovery and in facilitating adaptations to exercise, are promising, although more evidence on this matter is needed.
The Barça Innovation Hub team
Cheng, A. J., Willis, S. J., Zinner, C., Chaillou, T., Ivarsson, N., Ørtenblad, N., … Westerblad, H. (2017). Post-exercise recovery of contractile function and endurance in humans and mice is accelerated by heating and slowed by cooling skeletal muscle. Journal of Physiology, 595(24), 7413–7426. https://doi.org/10.1113/JP274870
Leeder, J., Gissane, C., van Someren, K., Gregson, W., & Howatson, G. (2012). Cold water immersion and recovery from strenuous exercise: a meta-analysis. British Journal of Sports Medicine, 46(4), 233–240. https://doi.org/10.1136/bjsports-2011-090061
McPhee, J. S., & Lightfoot, A. P. (2017). Post-exercise recovery regimes: blowing hot and cold. Journal of Physiology, 595(3), 627–628. https://doi.org/10.1113/JP273503
Roberts, L. A., Raastad, T., Markworth, J. F., Figueiredo, V. C., Egner, I. M., Shield, A., … Peake, J. M. (2015). Post-exercise cold water immersion attenuates acute anabolic signalling and long-term adaptations in muscle to strength training. The Journal of Physiology, 593(18), 4285–4301. https://doi.org/10.1113/JP270570
Tamura, Y., Matsunaga, Y., Masuda, H., Takahashi, Y., Takahashi, Y., Terada, S., … Hatta, H. (2014). Postexercise whole body heat stress additively enhances endurance training-induced mitochondrial adaptations in mouse skeletal muscle. American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, 307(7), R931–R943. https://doi.org/10.1152/ajpregu.00525.2013
An article published in The Orthopaedic Journal of Sports Medicine —in which members of the club’s medical services participated— now suggests to consider the detailed structure of the area affected, and treating the extracellular matrix as an essential player in the prognosis of the injury.