What is strength curve design?

Strength curve design refers to the variation in resistance that occurs throughout the range of motion when performing an exercise. It essentially adapts the resistance to match the natural strength capacities of your muscles at different points in the movement.

Sal Di Stefano and Adam Schafer discuss this concept in the context of exercise machines like those made by Hammer Strength. These machines are designed so that the resistance is lighter where the muscles are weakest (usually at the starting position) and heavier where they are strongest (often toward the end of the movement). This design makes the exercise feel more natural and can optimize muscle engagement and growth by matching the strength curve to the body's capabilities 1.

For example, with a Hammer Strength chest press, the resistance is lighter when the arms are close to the chest (where you're typically weaker) and gets heavier as you extend your arms fully (where you're stronger). This same principle is applied across various machines like rows and shoulder presses. Additionally, adjustable pulley systems in some selectorized equipment allow customization of the strength curve for even more tailored resistance profiles 1.