Muscle Fibres Learning Outcomes All are able to apply knowledge of the fibres to sporting events Most are able to explain the role of the motor unit in contraction. Some are able to apply knowledge to a range of sporting activities.

Homework Write up a neat copy of your extended question to be marked Prepare for Mock exam – Tues 7th October Bring in file with all Muscle Notes

The motor unit is

Motor unit Stimulation of one motor neuron causes all the muscle fibres in that motor unit to contract simultaneously. Each muscle is made up of a number of units. The number recruited varies depending on strength required. Number of fibres within a motor unit is dependent on control required. Small muscle for fine motor skill Large muscle for gross skill

Motor unit Motor units are usually made up

All or none law The innervation (stimulation) of a muscle occurs when a motor neuron transmits a nerve impulse to the muscle fibre. The all or none law states

Graduation of contraction Give handout – diagrams The force exerted by a muscle is dependent on:

Graduation of contraction Timing: spatial summation – To create a greater force of contraction the brain recruits more and larger motor units.

Effect of training Resistance training will result in some long term physiological responses to the neuromuscular system:

Plenary Activity Individually explain how the strength of muscle contraction can be varied in relation to a high jumper and a distance runner. Share this information with a partner between you come up with an agreed answer. Be prepared to share this information

Exam Q Complete this question in pairs: How can a performer vary the strength of muscular contractions to ensure that a skill is completed correctly? (4 marks)

Extended question In pairs use your notes to complete a draft version of the extended question.