1. MUSCULOSKELETAL SYSTEM
The musculoskeletal system consists of muscles, tendons, ligaments, bones and cartilage.
These support your body and enable it to move.
The different parts of your muscles and skeleton are under the control of the musculoskeletal system to allow us to move.
Impulses from the nervous system cause muscles to contract.
When a muscle contracts, it shortens, pulling on the bone to which it is attached.
The skeletal system forms the framework of the body but the muscles form the fleshy part.
Our muscles help us to move, maintain our posture and produce heat.

2. INCREASE IN BLOOD SUPPLY INCREASE IN MUSCLE PLIABILITY
As soon as we start exercising the muscles in our body get warmer and contract more rapidly. This is because our muscles need to contract to produce movement. As a result of this increase in muscle contractions there is a greater demand for oxygen, as these provide the energy for muscle contractions. Oxygen travels round our body via the red blood cells.
The increase in blood supply during exercise is achieved by a variety of physiological changes within our body. One effect is our heart beating faster and capillary dilation. This is when our capillaries get bigger to allow the increased blood flow to get to the working muscles.
INCREASE IN MUSCLE PLIABILITY
When we start exercising our muscles get warmer. This makes our muscles become more pliable. This means that our muscles become more stretchy and will reduce the risk of injury. It also means that during sporting actions we are able to stretch further.

3. INCREASED RANGE OF MOVEMENT MUSCLE FIBRE MICRO TEARS
A short term effect of exercise on our musculoskeletal system is an increased range of movement at our joints, When we exercise the increase in movements stimulates the secretion of fluid. As a result of exercise this fluid becomes less viscous. This means that it reduces in thickness and results in an increased range of movement. Therefore, it is easier to perform some sporting actions.
MUSCLE FIBRE MICRO TEARS
When we participate in exercise our muscles are put under stress. For this to occur we must overload our muscles by making our training sessions harder. During this process tiny tears occur in our muscle fibres. These muscle tears cause swelling in our muscle tissue, which causes pressure on the nerve endings which can cause pain. This can only be improved if our body has sufficient fuel (eating food groups such as protein) and rest to repair these micro tears. This will make the muscle a little bit stronger than it was before, which will be an advantage in our future sporting performances.