At what angle is the mechanical advantage of a muscle greatest?

The mechanical advantage of a muscle is greatest at an angle of 90 degrees because this angle allows for optimal force generation and efficient movement. At 90 degrees, the line of action of the muscle force is perpendicular to the lever arm, maximizing the torque produced by the muscle. This positioning allows the muscle to exert its force most efficiently against the load it is acting upon, providing the best leverage.

In contrast, at angles less than 90 degrees, mechanical advantage decreases because the muscle force begins to work more parallel to the lever arm, resulting in less torque. At angles greater than 90 degrees, the effective force angle also reduces the lever arm’s ability to produce torque, which similarly diminishes mechanical advantage. Thus, the unique characteristics of the 90-degree position make it the most effective for maximizing the output of muscle force in relation to the lever system of the body.