Sunday, 29 March 2015

Stretching the good, the bad and the ugly

Many practitioners (myself included once upon a time) still give out static stretches to all patients without considering the impacts of different types of stretching. Static stretching is best described as holding a specific position with the muscle on tension to a point of a stretching sensation and repeated. Typically static stretching exercises have traditionally formed an integral part of the warm-up  and it has been suggested that static stretching before activity promotes improvements in performance ), and increases range of motion. This was and still is considered to be true. However, studies are now challenging the value of the conventional static stretching warm-up and its ability to improve physical performance. In fact some studies suggest the opposite that static stretching reduces performance ! Oh dear not great advice then !
In fact static stretching may inhibit performance by reducing force production, balance, reaction time, sprint times, and power output.

Another gem often said is that static stretching reduces injuries. Current research implies that that stretching before exercise does not reduce the risk of injury (here is the article)

Another common belief is that static stretching elongates the muscles again studies suggest that rather, the subject may simply have an increased tolerance to stretching (ability to withstand more stretching force).

As a result from this evidence an alternative to static stretching is that dynamic stretching be performed in a warm-up prior to activities.

The benefit of dynamic stretching incorporates whole body movements and involves actively and rhythmically contracting a muscle group
through part of its functional ROM . This acts to elevate core body temperature, enhance motor unit excitability, improve kinaesthetic awareness, and maximize active ROMs . Dynamic stretching may include skipping, hopping, jumping, and rotation motions of the extremities, such as arm and leg swings (10,11,22). A proposed physiological rationale for replacing static stretching with dynamic stretching in a preperformance warm-up lies in mechanical (viscoelastic) and neuromuscular tissues changes.

In contrast to static stretching, dynamic stretching is not associated with strength
or performance deficits, and actually has been shown to improve dynamometer-measured power.

So before activity dynamic stretches
After activity static stretches held for between 15 to 30 seconds