Hi Akl,

There are different force acting on the body in various way. The acting force in the body may be an external or an internal force. As we increase the external force the muscle activity increase to a limit to overcome the force and vise versa. So the forec and muscle activity seams to be directly proportional. The internal force generated by the contraction of the muscle is also directly proportional to the state of the muscle. Whenever any muscle activity happen the internal as well as the external force always act on it according to demand of the muscle activity, but it may have different amplitude, magnitude...

Thank you for answer Ratan Khuman, I ask this question to know if found any method or equation to relate Force( e.g. output data from force platform) with muscle activity ( output data from EMG) in vertical jump.