By Susi Davies

When we have the ability to move every joint in our body through its full range of movement without any crackling noises, muscular tension, stress or  discomfort we know that our joints are in tonic condition - our joints have total freedom of movement. However for a lot of people this is not the case. A lack of balance between muscle tone and elasticity and a healthy connective tissue (which surrounds muscles) are usually the case. Flexibility varies for every individual depending on what type of activities we engage in, our age, sex, weight, genetic postural imbalances, injuries, pain, body conditioning and our emotional mood state.

Our joints function at its best at the age of 3 - 5 generally speaking, and for some it is maintained into the preteen years.
When two bones meet within the body - they create a joint. On the tips of the joints there is usually a cartilage to cushion the touching of the bones whilst in movement. Around the joint is a capsule containing synovial fluid that lubricates the surface to provide easy and smooth movement.

During normal motion, muscles contract (the agonist) on one side of the joint whilst the muscles on the other side simultaneously relax. For instance when we bend the knee - the hamstrings (muscles on the back of the leg CONTRACT) whilst the muscles at the front of the thigh the QUADRICEPS have to RELEASE and RELAX. If the person's nervous system has not learnt to relax the opposing muscle during motion, it can compress the joint space and create damage to the cartilage or joint capsule.

So when you feel a slight burning sensation, which we so generally call "stretching" it is in fact an actual RELAXING of the muscle or a RELEASE  of TENSION, which terminology I prefer. A muscle is already at it's normal length, it cannot really be 'stretched'. So if someone is tight in a certain muscle group, it basically means that those muscles are in a state of constant contraction. If we contract something constantly it will refer over to other body parts and can create havoc all over our body as well as in our mind. The key to releasing tension is to BREATHE. Slow, deep, rhythmic, long EXHALATIONS will send a relaxation response to the muscles "to letting go". It is that simple, but for some reason, sometimes we tend to push ourselves to 'force" more and to hold the breath when it hurts a little. Practice breathing better instead of "stretching" more.

When muscle fibres contract, meaning the origin and insertion come closer together, it is called a CONCENTRIC Contraction. When the muscle fibers LENGHTEN so that origin and insertion move away from each other, it is called an ECCENTRIC Contraction.  When a muscle contracts without changing it's length at all - it's called an ISOMETRIC contraction. When you apply resistance to a muscle when you want to move it's called an ISOTONIC contraction.

When we do yoga poses, we always pay attention to getting in and out of the poses in slow motion as well as to holding the poses for a certain amount of time - so that you can reap the full benefits of all those muscle contractions.

Let's use the example of your BICEPS  - inner upper arm muscle. You grab hold of a bag of potatoes at the markets. You pick up the bag and move it towards your body - the biceps are working CONCENTRICALLY - you then hold the back up in the air for a few seconds, whilst you are waiting to be served - the biceps are now in an isometric contraction (no movement) - then the potatoe seller is ready to take your bag and put it on the scales - so you SLOWLY reach forward with your bag in hand to pass it on. Your bicep is now working Eccentrically. If you now, would like to add on an isotonic contraction - you could simply hang on to your bag like crazy when the stall seller would want to take it off you (resistance work). He may think you have totally lost the plot - however you know that you are only doing an isotonic contraction of your bicep.

So as we are coming into Christmas - remember to take a gift is a concentric contraction, to pass on a gift is an eccentric contraction. To hang on to a gift that is meant for someone else is isometric and can end up in an isotonic if the receiver will want it desperately!