Muscles + Muscle Work

Question 1

Isometric

Answer 1

> Static
increase in tension with no muscle length change - no movement produced
Internal muscle tension = external force

Question 2

Isotonic

Answer 2

> Dynamic
Increase in tension causes muscle length change - movement is produced

> Concentric - muscle shortens
Internal force > External force
Eccentric - muscle lengthening
Internal force < External force

Question 3

Isokinetic

Answer 3

• producing constant speed

Question 4

Reciprocal Inhibition

Answer 4

• ‘relaxation’ of opposing muscles to allow movement

- reciprocal lengthening + shortening is passive so doesn’t count as muscle work

Question 5

Range of muscle work vs movement at joint

Answer 5

Muscle work

• Fully shortened - Inner
• Fully lengthened - Outer
• anything between is middle

Joint range

e. g for flexion
- Early = full extension
- middle = between
- late = full flexion

Question 6

Types of muscles (arrangement of fibres)

Answer 6

> Circular (sphincters) - closes + opens orifices
Multipennate - many striations in one area for power (deltoid)
Fusiform - multiple origins + insertions - wider in centre (biceps brachii)
Bipennate - 2 striations in one muscle (Rec Fem)
Unipennate - striations in one direction (EDL)
Parallel - parallel fibres in one direction (Sartorius)
Convergent - many origins to single insertion - fibres often produce different movements (Pec maj)