Question

How do frogs utilize extensor and flexor muscles in order to swim, jump, and do other frog things efficiently; include specific names of these muscles located in the upper and lower limbs of the frog?

Answer 1

The muscles in the stomach of the frog bend the spine forward, opposing the muscles in the back which bend the spine backwards. The upper muscles in the chest help to push the upper limbs out using triceps brachii as extensors to jump, while the upper back muscles help to draw the upper limbs back in as well as biceps brachii. The pectoralis major are responsible for moving the arms at the shoulders. The rectus abdominus bends the spine downward and also adds an extra layer of protection for the frogs internal organs. There are muscles on top of the theigh such as the satorious, which extend the lower legs to kick out when jumping or swimming. The tribalis anterior longus is a flexor of the foot, meaning it pulls the foot up, one uses this muscle when they lift their foot to take a step. The gastrocenemius is an extensor for the foot, bending it down, used whenever a frog jumps.

Answer 2

The structure of the feet and legs varies greatly among frog species, depending in part on whether they live primarily on the ground, in water, in trees or in burrows. Frogs must be able to move quickly through their environment to catch prey and escape predators, and numerous adaptations help them to do so. Most frogs are either proficient at jumping or are descended from ancestors that were, with much of the musculoskeletal morphology modified for this purpose. The tibia, fibula, and tarsals have been fused into a single, strong bone, as have the radius and ulna in the fore limbs (which must absorb the impact on landing). The metatarsals have become elongated to add to the leg length and allow the frog to push against the ground for a longer period on take-off. The illium has elongated and formed a mobile joint with the sacrum which, in specialist jumpers such as ranids and hylids, functions as an additional limb joint to further power the leaps. The tail vertebrae have fused into a urostyle which is retracted inside the pelvis. This enables the force to be transferred from the legs to the body during a leap
The muscular system has been similarly modified. The hind limbs of ancestral frogs presumably contained pairs of muscles which would act in opposition (one muscle to flex the knee, a different muscle to extend it), as is seen in most other limbed animals. However, in modern frogs, almost all muscles have been modified to contribute to the action of jumping, with only a few small muscles remaining to bring the limb back to the starting position and maintain posture. The muscles have also been greatly enlarged, with the main leg muscles accounting for over 17% of the total mass of the frog.