The inverse relationship in muscle
The force-velocity curve describes how the maximal force a muscle can produce during a concentric (shortening) contraction falls as the speed of shortening increases. At very low velocity, near isometric, force is highest; at high velocity, force drops toward zero. The relationship was characterized by A.V. Hill and is hyperbolic for concentric actions.
Eccentric (lengthening) contractions behave differently: force can exceed the isometric maximum as lengthening velocity increases, which is why the full curve is not symmetric around the isometric point.
How it maps to training
Coaches use the curve to target qualities along the spectrum. Heavy, slow lifts train the high-force end; light, fast movements such as jumps and throws train the high-velocity end; ballistic and plyometric work targets the middle power region where force times velocity peaks. Programming across the curve is a common periodization strategy. This is general information, not individualized medical or rehabilitation advice.