Watts per kg of muscl

Long legs benefit by increasing the time and distance over which the animal can push against the substrate, thus allowing more power and faster, farther jumps. Large leg muscles can generate greater forces, resulting in improved jumping performances. Many jumping animals have not only elongated the normal leg elements, but have also elongated other parts of the limb, such as foot and ankle bones, effectively adding more segments to the limb and even more length. Frogs are an excellent example of all three trends: frog legs can be nearly twice the body length, leg muscles may account for up to 20% of body weight, and they have not only lengthened the foot, shin and thigh, but extended the ankle bones into another limb joint and similarly extended the hip bones and gained mobility at the sacrum for a second 'extra joint'. As a result, frogs are the undisputed champion jumpers of vertebrates, leaping over 50 body lengths, more than 8 feet.Grasshoppers are known to use elastic energy storage in order to increase jumping distance. As noted above, power output is the strongest determinant of jump distance, but the power that muscles can generate is limited due to physiological constraints of the muscles themselves to approximately 300

Watts per kg of muscle. In order to circumvent this power limitation, grasshopers anchor their legs via an internal 'catch mechanism' while their muscles stretch an elastic apodeme (similar to a vertebrate tendon). When the catch is released, the apodeme releases its energy all at once, at a much higher power output than muscles are capable of. This would be analogous to a human throwing an arrow by hand versus using a bow - the use of elastic storage allows muscles to operate closer to optimal, generating more force and doing more work, while the elastic element releases that work faster than muscles can. The use of elastic energy storage has been found in jumping mammals, as well as in frogs,and the increase in power can be from two- to seven-fold.