Is Stretching Out-of-Date?

Summarized by Robert W. Griffith, MD
September 27, 2002 (Reviewed: September 3, 2004)

Introduction

All of us who try to keep fit are well drilled in the idea of stretching out the muscles before, and after, exercise. And for many of us, in spite of the known benefits of stretching, it's merely a rather boring, time-consuming part of the exercise activity. However, we are assured it is necessary to avoid muscle soreness or risk of injury. Now two Australian physical therapists have published a survey of medical publications that examines the benefits of stretching in relation to exercise.

The authors were able to find eight studies in the medical literature that met minimal quality requirements. One concerned stretching routines and athletic performance, and was not discussed further. Five dealt with soreness after exercise, and two with exercise-related injuries.

The effect of stretching on delayed muscle soreness

All the subjects were healthy young adults. Three studies looked at stretching before exercise, and two at stretching after exercise. Stretching times ranged from 5 minutes to 10 minutes. Scores for soreness were recorded at 24, 48, and 72 hours after exercise.

Results from 77 subjects were pooled. Stretching routines were found to produce an extremely small reduction in muscle soreness, which was non-significant (i.e. this result could readily have been produced by chance alone).

The effect of stretching on risk of injury

Both these studies were done in military recruits during their 12-week initial training period. In one study, 1500 recruits did physical training on alternate days for 11 weeks; the 'experimental group' did 20 seconds stretching of leg muscle groups before exercise. In the other study, 1000 recruits underwent a similar exercise regime; the experimental group did 20 seconds of calf muscle stretching before exercise.

The focus was on injuries involving the foot, ankle joint, Achilles tendon, and lower leg. The recruits were rated as having sustained an injury if they were unable to return to full duties within three days.

A total of 181 injuries occurred in the 1,284 recruits in the stretching groups, and 200 injuries in the 1,346 control (non-stretching) group recruits. The difference between the frequency of injuries in stretching and non-stretching recruits was not significant; i.e. it could have quite readily occurred by chance alone. If indeed the results were 'real', a person would have to stretch before each exercise session for 23 years to avoid one injury!

So, what are the benefits of stretching?

The survey done by the authors shows clearly that stretching before or after exercise has no effect on delayed onset muscle soreness, and has no meaningful effect on the occurrence of injuries. An earlier survey reported similar findings. However, it would be wrong to dismiss stretching as merely a 'waste of time' for everyone, based solely on these studies.

First, the subjects in all the studies reported were "young". Today, many elders are exercising, sometime strenuously, and the benefits of stretching might be expected to be different in aged muscles and tendons.

Second, there's little doubt that stretching by older people leads to increased (or at least, preserved) flexibility. This is important in preventing falls, if nothing else.

Third, stretching has a hedonistic, or pleasurable component - it's highly enjoyable, depending on the setting. One has only to look at the contentment shown by a cat (or even a dog) as they stretch after a nap.

So, one may conclude that it may not be helpful, or necessary, to stretch before and after every exercise session, but there's a lot to be gained from a good stretch now and then - even if the benefits are largely in the mind.

Sources

• Effects of stretching before and after exercising on muscle soreness and risk of injury: systematic review. RD. Herbert, M. Gabriel, BMJ, 2002, vol. 325, pp. 468--470
  
  
• Reducing risk of injury due to exercise. D. MacAuley, TM. Best, Editorial. BMJ, 2002, vol. 325, pp. 451--452
  
  

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