Mistaken if nature?

Comprising the mass of muscle fibers, each skeletal muscle is attached one end to a bone, others - to another, exchanging through the joint. The only way she can move. This way, musculoskeletal levers, which almost always there is a loss in force.
Consider, for example, bending forearm in the elbow joint. Forearm in this case can be considered a second class lever to the pivot point of the elbow.
bicepBiceps the biceps muscle shoulder) is attached to the elbow bones at 3 cm from the axis of rotation of the joint, and the cargo compressed using the brush is 30 cm from it. The attitude of the shoulders leverage to 10:1. It means to hold in a bent arm shipment to 16 kg, muscles should develop effort to 160 kg of Similar relations develop on foot. Its front part, which we base when walking, 6 times longer than the rear, which is attached calf. The axis of rotation arm - in this case , the ankle joint. If a person weighing 70 kg rises on the toe of one foot in the ordinary walk, his calf should develop effort in 6 times more, i.e. 420 kg No accident such a powerful is our Achilles tendon. It is like living the cable attach the muscles to the heel bone and can withstand the load in half a ton and more.
The question arises, did not know the nature, reducing many times the strength of our muscles. Of course, the body is not perfect. It has a number of inconsistencies and imperfections, which we will talk. However, in this case the nature was not mistaken. Losing in force, we, according to the same law of the lever, the same gain in speed of movement. Calf will be reduced by 1 cm, and the heel during this time already on 6 cm soar above the earth. For animals speed gains were more important than the gain in strength.