08/06/2026
It's not that deep, but we can make it as complicated as we like so here goes...
Resistance profiles - a visual representation of how external factors like load, gravity, or body position can influence the difficulty of an exercise in certain portions of the movement.
Strength curves - a visual representation of how internal factors such as internal moment arms affect the difficulty of certains portions of a movement.
Moment arm - the perpendicular distance from a pivot point or axis of rotation to the of pulling or pushing force (line of action) usually gravity or a cable from a machine.
Torque - the rotational force that causes movement around an axis of rotation (a joint). More torque means more tension.
It's just basic physics.
Understanding how these things affect the stimulus you're giving your body will ultimately influence the results you get from the exercise and how you perform it.
If not you're not that serious about it, just flex your elbow hard and you'll be fine. If you want accurate results for specific goals then hopefully this will help.
Pro tip - it works for all muscles and movements... You can train any joint action you like, in any way you want.
