Stretching It Too Far

Two days ago, my friend Brad and I had a heated argument while working out at the gym. Brad insisted that I spend some time stretching before commencing our run on the track. He said he had always felt more comfortable that way. He even attributed his better running record than mine to my non-adherence and callous indifference to stretching protocols. In my defense, I quoted what I remembered about reading that stretching has been shown in research studies to be of no significant benefit in preventing injuries in sportsmen, and perhaps, even to be related to higher risk of injuries. Stubborn as we both were, we failed to consider each other's points of view (even though we verbally confessed that we did!) and ran our own ways around the track. I realized later that neither of us were totally right or wrong in our assessment of the requirement of stretching during a workout.

Firstly, stretching is often confused with warming-up, the latter being the performing of the activity in a slower and gradually accelerated way. Whereas warming-up has been considered to be of help in improving performance efficiency, all the studies that showed stretching to be beneficial did not consider the confounding aspect of warming-up in their plans. Stretching obviously contracts and relaxes the muscle fibres to its maximal extent, thereby increasing flexibility around a given joint. This may be important when indulging in sports that require good flexibility like for gymnasts and figure skaters. When not needed as in running, excessive flexibility can cause muscle instability and decrease total force production. Even sports medicine scientists agree that the benefits of stretching in causing subjective improvement in performance is something that cannot be quatified by research. One of the reasons why Brad felt compelled to stretch each time could be that stretching induces production of hormones called endorphins that are natural pain-killers produced by the brain. This is probably responsible for the 'runner's high' that athletes experience and that scientists and doctors have failed to reproduce in lab experiments. These are the same endorphins that are also linked to the effect of placebo in controlled experimentation.

So finally, what's good and what's not with stretching? Stretching techniques can be of several types: ballistic, dynamic, static and propioceptive neuromuscular facilitation (PNF). Repetitive bouncing movements as in ballistic is definitely not recommended whereas dynamic stretching that mimics the activity to be performed in an exaggerated yet controlled manner can be as useful as warming-up. Static stretching of muscles by holding them at the point of discomfort is a popular method and useful if done for limited periods of time and severity. PNF requires a partner and involves both agonistic and antogonistic muscle groups (eg. biceps and triceps) and produces the greatest benefit in flexibility. Thus, stretching can help maintain flexibility which declines with age or inactivity due to an injury. Also, stretching may be more safely performed after exercise, when muscles are warm. As a final word, I have come to believe that like most things, stretching is good as long as done in moderation to suit the kind of activity done. Indeed, both Brad and I never imagined this topic to be as equivocal as it turned out to be!