In muscle fibre arrangements the muscle fibres run on angles from the tendons.

A larger number of muscle fibres in this arrangement allows muscles to generate greater forces than fusiform muscles but they are slower.

Fibres on one side of a tendon

Fibres on either side of a tendon

Fibres branching out from multiple tendons

Fibres best suited to high intensity (anaerobic) strength & power activities, contract rapidly, contract with greater force, have a large fibre diameter, have the capacity to contract for only shorter time periods and fatigue easily.

Fast twitch fibres that are anaerobic

Fast twitch fibres that are partially aerobic

Fibres that are best suited to endurance ( aerobic ) activities, contract slowly with less force, have the capacity to contract for longer time periods, don’t fatigue easily, have high mitochondria density.

muscle action where the load or resistance against the muscle is constant throughout the motion.

Isoinertial movement where the muscle length decreases and the isoinertial movement where the muscle length increases

Movement where the muscle length remains unchanged ( gripping a racquet handle )

Movement where the resistance changes according to joint angle

The types of muscles

Calcium is released which bonds the cross bridges to the actin, Cross bridges begin to pull the actin filaments towards middle, muscle contracts and shortens.

Filaments in a sarcomere

known as the all or nothing rule the fibres in a motor unit will contract fully at the same time, to vary the intensity of a movement

Muscles working in pairs with an agonist and antagonist

In the upward motion of a squat the hip, knee and ankle joints make movement of

Example of a isoinertial concentric contraction