Stretching for the endurance runner: What does the evidence say?
Baxter et al (2017) have conducted a systematic review of the evidence available regarding the efficacy of stretching for the endurance runner. To read the full article, click on the link below:
Baxter et al (2017) herein known as The researchers defined endurance runners as anyone who runs a distance of 5km or more. They did not state the frequency or cadence of the event. Until recently, stretching was always assumed to be beneficial, without scientific support. The general consensus was, that there was a gain from stretching prior to exercise and for long term gain, however, the research has been sketchy! Therefore the researchers created this systematic review of the current evidence. 1. Stretching and flexibility
The researchers systematic review concentrated on static stretching (stretches performed whilst being in one position). Until the review, we believed that sustaining a stretch for 30 seconds was the optimal, yet frequency remained uncertain. The researchers review concluded that stretching over a minimum of a 6 week period increases flexibility
2. Are endurance runners flexible?
The researchers identified that elite endurance runners are not as flexible as their non-elite counterparts! The researchers highlighted that muscle hypertrophy (larger muscles) can reduce the range of motion to a joint and therefore flexibility. A study by Nicholas (1990) identified that there is a link between reduced flexibility and improved economic running style. Tightness in muscles is postulated as increasing elastic storage and therefore reducing oxygen demand on the muscles. Changing flexibility will not increase or decrease the likelihood of a running related injury. 3. Stretching and Performance
The evidence conflicts as to whether stretching affects performance. It was proven relatively recently (Wilson et al, 2010) that stretching before and event, inhibits performance as it reduces the ability to store elastic energy. The researchers stated that there is no evidence that stretching improves ability, and there is an ongoing debate as to whether stretching before an event decreases running economy.
Additionally, the researchers identified that muscle stiffness is a desirable trait in endurance runners. They go on to state that Inflexibility in the hip and calf was beneficial in joint stability. The researchers also identified that stretching can increase the number of motor units (the area where the nerve joins to the muscles) and therefore increase the work rate required to perform the task. Not withstanding, stretching cold muscles can strain the muscles leading to a decrease in force 4. Long lasting effects of stretching and performance The researchers stated there have been no studies to demonstrate whether running economy improved or worsened from a long-term stretching program. It has little benefit in an endurance runner's preparation. The researchers stated that further research is required into the effects of long-term stretching. The researchers also identified that the effects of dynamic stretching (stretches that require movement) is limited and further investigations are needed. The researchers also highlighted that the literature reviewed shows that the benefits of stretching are still hypothesised and lack an explanation 5. Stretching and DOMS
Delayed Onset Muscle Soreness (DOMS) typically lasts for 24 - 48 hours past strenuous exercise. Typically after down hill work or to the novice runner, or from increasing work rate too soon. DOMS is an unknown entity. Chemical? Damage? We still do not know! DOMS and stretching has been disproven even as far back as 1989! There is no significant difference between stretching and DOMS. It is suggested that superficial techniques are used, for example: message and / or heat treatments. This was followed up much more recently, (Herbert et al, 2011) who added that neither static or dynamic stretching has an effect on DOMS either reactively or proactively!
6. Stretching and chronic injury Here, the evidence concentrates of stretching and chronic, long term degenerative (over use) injuries. For example: ITB friction, achilles tendinopathy and plantar fasciitis. Owing to the majority of the elite population are in their 20's and 30's and yet the etiology for the non-elite runner is 35 - 50, these conditions are of a high risk. The researchers stated that there was no evidence to suggest that stretching has any positive impact on such conditions. It was identified that endurance athletes are unlikely to succumb to muscle strains owing to working at muscles sub-maximal levels, and do not require explosive forces. Numerous studies have been conducted to prove that stretching does not affect the prevalence of overuse injuries The only benefit of stretching in injury terms is to maintain range of motion following injury. In conclusion, This systematic review suggests there is no significant advantage for stretching with endurance runners. It is suggested that a progressive warm up be conducted and to individualise their training programs and to include; resistance training, planned and progressive training, and cross training and interval training to reduce the likelihood of overuse injuries. References available on request. Article citation: Impact of stretching on the performance and injury risk of long-distance runners. Baxter et al (2017) Research in Sports Medicine. pp:78-85.
