Muscle Contraction Types

Muscle tension

Force generated by a muscular contraction

Isotonic Contractions

Iso - Same

Tonic - Tension

Tension in the muscle remains constant.

Length of the muscle changes.

Two types:

• Concentric contraction (Shortens)

• Eccentric contraction (Lengthens)

Concentric Contraction

Muscle Shortens

Eccentric Contraction

Muscle Lengthens

Isometric contraction

Iso - Same

Metric - Length

Tension in the muscle remains constant.

Length of the muscle remains constant.

Why does the muscle length not shorten for all contractions?

The connective tissues present ant tendons hold the muscle tight in position during all contractions.

• Sarcomeres do get shorter

• However overall muscle length with the tendons and connective tissue can vary dependent on the contraction

Muscle Fibre types:

Slow Twitch Fibres

Contract very slowly

Aerobically respirate to product ATP

Need more oxygen

Can function for long periods sans fatigue

Suitable for endurance exercise

Muscle Fibre types:

Fast Twitch Fibres

Contract very quickly

Anaerobic glycolysis to product ATP

Do not need much mitochondria

Do not need oxygen to contract

Can function for short periods, fatigue quickly

Rapid/forceful contractions

Suitable for resistant exercise

Muscles get thicker

Sarcopenia

Muscle gets weaker and smaller, atrophies.

Age-related condition, irreversible.

• Muscle cells begin to die with age, replaced with connective and adipose tissue.

• Ability to produce powerful contractions declines

Can be delayed to some extent with age