Stretching and warm-up

In the most basic form, stretching and warm-up are two completely different things.  They can be combined and used together, but they have two distinct purposes.

– Stretching is used to lengthen the muscles and increase elasticity through a sustained force placed on the muscle.

– A warm-up is used to prepare the body for a specific type or set of actions.

A stretch held for less than 8 seconds has absolutely no effect on the body.

Once an external force is placed upon the body, the structures it affects sense the force and sends a signal to the spinal cord, the spinal cord in turn sends a signal back to the muscles which prompts them to relax and move more freely. The total time for this exchange takes 6-8 seconds. It is referred to as the Golgi tendon reflex.

Therefore when stretching, one end of the muscle needs to be pulled away from the other, so the stretch can be felt into that particular muscle. This then needs to be held for a minimum of 8 seconds. If possible, the best way is to repeat the stretch 3 times per muscle.  However – if time is an issue – one repetition of a stretch that is held long enough (at least two sets of ‘ichi, ni, san, shi – go, roku, shichi, hachi’ as the count is almost always faster than 8 seconds!) before changing to the other side/limb is a good minimum to work from.

Once the body is efficiently stretched this way, any warm-up done is much more effective and the risk of straining, tearing or damaging muscles or tendons is majorly reduced.

It is important to remember that an ideal warm-up should be a low intensity version of the exercise that the warm-up is for.

A person about to swim would not usually be told to go for a jog beforehand – instead they would carry out a gentle swim to prepare the body for that action.  In Kendo, we can use exercises such as suburi for this reason – a specific set of movements that start at a slower pace and build in intensity, preparing the body for kihon and ji-geiko.

Where stretching and warm-up may crossover is when kiai is introduced to a stretching routine.  Kiai with stretching can work to warm-up the body by increasing the exertion with extremely loud shouting (this is helps to keep count of how long a stretch is been held for!).  That being said –  exercises and movements such as rolling the head from side to side or swinging the arms in large circles do have a use.  They are closer to that of a warm-up action as you are placing movement through the joints and structures of the body.

To conclude:

Stretches must be held for 8 seconds or more and repeated if possible. This gives the body a chance to respond to the stretch and for the tissues to move.

Combining a warm-up and stretching routine is fine, as long as the stretches are held for long enough!

About the author:
James Ogle is a Kendo 4th Dan, British team member.  He holds a BSc in Sports Science, MSc Performance Analysis, and UCAPD Sports Massage.  He works as a fully qualified soft tissue therapist and sports massage practitioner and has studied the human body, its responses to exercise, stretching, and physiology for over 15 years.