A2 - Muscular System

• Depending in the type of exercise intensity, different muscle fibres will be recruited to complete the activity
• Each type of muscle fibre is stimulated at different intensities - this process is called muscle fibre recruitment
• When the muscles need to produce a large force such as lifting a very heavy weight, the type IIx muscle fibres will be recruited in order to produce these large amounts requiring a lot of force
• When a person is walking, slow contractions and low forces are required so type I muscle fibres will be recruited
• Blood flows through the body through arteries, arterioles, capillaries, veins and venules
• When a person is exercising or taking part in a sport, blood is directed to the muscles that are working through vasodilation of the blood vessels leading to the muscles and vasoconstriction of the blood vessels leading to areas of the body to reduce the blood flow to areas of the body where blood is not required
• When a person is exercising or taking part in a sport, blood is directed to the muscles that are working - so, if a person is running, more blood will be directed to flow around the leg muscles so that oxygen and nutrients can be delivered to these muscles so that they can function
• During exercise or sports participation, blood is also directed to flow through blood vessels that are close to the skin surface to help to cook the body down
• When taking part in resistance exercises such as lifting weights, the process is actually designed to break some muscle fibres. These 'breaks' are called 'micro-tears' as the damage is usually very minimal. However, this 'damage' has to occur in order for the muscle to have the stimulation to rebuild itself so that over time it will become bigger and stronger
• During a warm-up we usually increase the heart rate and carry out mobilisation acivities.
• By increasing our heart rate, we are pumping out blood around out body at a faster rate which then has the effect of warming up our muscles
• When muscles become warmer they become more pliable (able to change shape more easily)