There are three important types of muscle contractions relevant for stretching. Isometric contraction is one in which no movement takes place, because the load on the muscle exceeds the tension generated by the contracting muscle. This occurs when a muscle attempts to push or pull an immovable object. Additionally, there are two types of isotonic contractions, where movement of the muscle does takes place. The first is concentric contraction where the muscle decreases in length such as lifting a weight up. The second is eccentric contraction where the muscle increases in length such as lowering a weight down. All three will be important for the various types of stretching:
- Ballistic stretching uses the momentum of a moving body or a limb in an attempt to force it beyond its normal range of motion.
- Dynamic stretching involves moving parts of your body and gradually increasing reach, speed of movement, or both.
- An active stretch is one where you assume a position and then hold it there with no assistance other than using the strength of your agonist (the muscles which cause movement to occur) muscles.
- A passive or static stretch is one where you assume a position and hold it with some other part of your body, or with the assistance of a partner or some other apparatus.
- Isometric stretching is a static stretch in which the muscles are tensed
- PNF (Proprioceptive Neuromuscular Facilitation) stretching combining passive and static stretching.
PNF Stretching has been said to be the fastest way to increase flexibility [Link].Typically these stretches are done with a partner actively stretching the participant. There are ways of doing it yourself however (PNF Self Stretching Techniques, Ninos, J. Strength and conditioning journal. Lawrence,Kan. 23(4), Aug 2001, 28-29.).
The benefits of stretching are numerous: reduced muscle tension, increased flexibility, enhanced muscular coordination, increased blood circulation, increased energy levels, as well as other physical and even psychological benefits [Link]. Stretching, like almost anything health related, is not without controversy and competing information. Athletes are often told to stretch after exercise in an effort to relieve soreness, but a study has shown this does not actually have any benefit and may be detremental to performance [Link]. Ballistic stretching is generally not recommend due to the increased chance of pulling a muscle due to the bouncing motion. However, a study showed that ballistic stretching provides similar gains in flexibility to other methods, without any negative side effects (Millar and Nephew 1999). Also, overstretching and putting too much strain on your muscles is potentially dangerous. It is always difficult to sort through the myriad information on these type of subjects, but the overall indication is that stretching in a safe and controlled manner regularly is beneficial.
My current plan is to implement stretching between my resistance exercises in order to be most efficient with my time. Over the next few weeks, I will try to experiment with various types of stretches and see which are most beneficial.