Movement and Locomotion (3)

The action of antagonistic muscles during walking (7)

The tibialis contracts to bring down the heel

The action of antagonistic muscles during walking (8)

As the right heel touches the ground, body weight is shifted to the right leg

The action of antagonistic muscles during walking (9)

The whole sequence is repeated by the left leg

Mechanism of locomotion in fish (2)

These antagonistic muscles act in opposite directions

Mechanism of locomotion in fish (3)

This enables a fish to whip its tail

Mechanism of locomotion in fish (4)

As the myotome on the right contracts, the one on the left relaxes

Mechanism of locomotion in fish (5)

The tail will be whipped to the right

Mechanism of locomotion in fish (6)

On the contrary, when the right myotome contracts, the left relaxes and the tail is whipped to the left

Mechanism of locomotion in fish (7)

Alternating waves of contraction and relaxation occur along the myotome

Mechanism of locomotion in fish (8)

The action causes parts of the body to move from side to side, pushing water backwards and sideways, and hence moving the fish forward