“You must always stretch before working out, otherwise you will risk injury” is a pretty common statement that floats around in the fitness world. But how true is it? And what is meant by stretching? I’m guessing that when most people hear the word stretching they think of static stretching where the muscle is stretched to it’s limit and then held in that position for some time. Some other forms of stretching include; dynamic, and Proprioceptive neuromuscular facilitation (PNF). Each type of stretching has it’s own benefits and suitability.
Static stretching pre-workout/ pre-performance can have detrimental effects on the subsequent performance. It forces the target muscles to relax, temporarily making them weaker. Static stretching also reduces blood flow to the muscles and decrease Central nervous system activity, disrupting the communication between the brain and muscles thereby limiting the capacity to generate force. A meta-analytical review by Simic, et al. looked at 104 different studies on the acute effect of static stretching pre-exercise, concluding that maximal muscle strength, muscle power, and explosive muscular performance decreased by −5.4%, −1.9% and −2.0% respectively.
Static stretching post exercise, however, has been suggested to increase long-term strength and may allow an athlete to address range of motion and prevent injury before going into the next session.
In short, PNF is a series of contract-relax cycles. Mobilise a position of restriction, build tension in the muscles that are limiting further mobilisation, such as resisting against an external force, hold for 5 seconds, release the tension and mobilise to a new range, hold for 10 seconds. These steps are repeated 5-6 times, until no more range can be achieved. Much like static stretching, when done pre-workout PNF can reduce performance levels, but is an excellent form of post-workout stretching.
Dynamic stretching involves moving through a full range of motion, without holding any one position. Dynamic stretching is the preferred method of stretching pre-workout for a number of reasons. It prepares the muscles and joints in a more specific manner since the body is going through motions it will likely repeat in the workout. It improves kinaesthetic awareness – that is the awareness of where the body is in space and time. Dynamic stretching is also highly effective in warming the body and will increase range of motion through joints, therefore exercises can be performed through their full range without compromising form due to muscular or joint restrictions.
In regard to the initial statement I would recommend dynamic stretching. Static and PNF stretching should be left for post-workout.