Fig. 2.

The relationship between force and the torque it effects is an important consideration at various structural and functional levels. a Changing effective levers and lines of pull affect both the torque effected by the external load and a muscle treated as a single force-producing unit [35]. b Alterations of exercise form, involving changes in the placement of the external load or the body positioning (e.g. stance or grip width), affect the amount of resistance experienced by different functional muscle groups. c Leverage and line of pull changes are also relevant on scales smaller than a muscle. Relative contributions of individual fibres vary through the range of motion of an exercise and are affected by hypertrophy