Part 2 - Why does it seem so hard to stretch?
Continuing our search for a flexibility training framework we now take a look at why it seems to hard to stretch at first and what are the implications for the frequency of our flexibility training sessions.
Before you get stuck in to this article please read the disclaimer.
Why is stretching so hard at first?
I'm not going to go into great detail here about the composition of muscle (sarcomere, myofilaments and the such like) but what I do want to do is draw your attention to how your body detects the fact that a part of it is being stretched and in turn how the body reacts.
Your muscle tissues contain special nerve endings called proprioceptors. Proprioceptors are the mechanism by which the body perceives its own position and movement. Proprioceptors are primarily found in special muscle fibres commonly called muscle spindles (also be aware that there are other similar sense organs such as the golgi tendon organ but for now we will just look at muscle spindles).
The muscle spindles detect two things: how much a muscle is being stretched and how fast that stretch is taking place. Once the proprioceptors have detected a stretch they transmit the information to the brain. The interesting thing is that your brain reacts to the signals from the muscle spindles by telling other types of muscle fibres to contract and to resist the stretch (this is called the stretch reflex).
This is an important fact - when you stretch a muscle the muscle reacts by resisting the stretch. It is this that makes stretching seem so hard at first.
So how do we overcome the stretch reflex? We overcome it by regular stretching of course. When you stretch regularly the muscle spindles stop reacting so strongly to the effects of stretching and send signals to the brain less frequently. As a result the muscles don't contract so strongly and are free to elongate more.
There are other physiological responses to regular stretching. Connective tissue such as ligaments will also be conditioned to 'give' a bit more than they did previously. In reality they will not give much because they are very strong and are not really designed to stretch. Most of your gains will come from overcoming the stretch reflex.
The key point to be aware of is that stretching must be a regular activity in order to train the muscle spindles not to fire so frequently. I suggest stretching every day if you can, especially when you are just starting out. Leaving stretching to one or two training sessions a week will not help you very much because it simply won't get the muscle spindles used to the effects of stretching. If you train like that you will experience session after session of discomfort as you fight the stretch reflex but you still won't see any gains in flexibility.
What next?
In the next article in this series we will look at how to stretch and introduce some practical guidlines.
Author: Andy French
