The externally-applied force can either vary across the whole joint angle range of motion, or it can remain constant.The effectiveness of a strength exercise depends on its velocity. Explosive strength is “the steepest increase in strength in the shortest possible time.” Jumping, bounding, plyometrics, and isokinetics are explosive.Now, let’s get into the methods of accommodating resistance Peak Contraction Maximal effort is at the weakest point of the strength curve (e.g., when using the pec deck and leg press).The greatest effort must be at the start, but approaching lockout (finish) it becomes easier due to the force-velocity.VRT is what you’re seeing when a lifter adds elastic bands or chains to the bar before a lift.This has the effect of increasing the resistance toward the end of the concentric phase of the lift.
This specificity likely arises because differences in external load type cause differences in describes how the externally-applied force changes throughout the range of motion of the exercise.
The cam allows the cam machine to produce variable resistance by the use of a chain, cable, or belt that tracks over the high and low spots on the kidney shaped cam so that the distance between the cam's axle, which is the point of rotation, and the weight stack varies.
The supposed purpose is to allow the muscle to be equally worked through all ranges of motion.
VRT is a relatively new aspect of training, and as such has not been well studied.
The basis of its effects and effectiveness are largely anecdotal.