Single-Joint Exercise

A single-joint exercise is an exercise in which the primary movement occurs at one joint. In resistance training, exercises are commonly classified as single-joint or multi-joint according to the number of joints contributing substantially to the movement. Examples of single-joint exercises include knee extension, in which movement occurs primarily at the knee, and a biceps curl, in which movement occurs primarily at the elbow .^1,2

Single-joint exercises are often used to emphasize muscles responsible for a particular joint action. However, the term does not mean that only one muscle is active. Several muscles can contribute to or stabilize a movement even when the principal motion occurs at a single joint. The classification refers to the joint movement involved rather than to the total number of muscles participating .¹

A multi-joint exercise, by contrast, involves substantial movement at more than one joint. For example, a squat involves coordinated movement at the hips, knees, and ankles, whereas a knee-extension exercise primarily involves movement at the knee. The two exercise types therefore differ in the number of joints contributing substantially to the movement .^1,2

Single-joint exercises are not inherently better or worse than multi-joint exercises. Research comparing the two indicates that their usefulness depends on the muscles, movements, and adaptations being targeted. In resistance-training programs, single-joint exercises may be used alone or alongside multi-joint exercises to provide more specific loading of particular muscle groups .^1,2