Single and multi-joint exercises
Exercises can be classified as either single-joint or multi-joint based on the number of joints used and the size of the muscle areas involved.
Multi-joint exercises use two or more primary joints and recruit one or more large muscle areas such as the chest, shoulder, back, hip or thigh. In contrast, single-joint exercises involve only one primary joint and recruit smaller muscle areas such as biceps, triceps, abdominals, calf, neck, trapezius, forearm, lower back, anterior lower leg. The spine is considered a single primary joint.
Single-joint exercises are especially useful for injury prevention and rehabilitation, whereas multi-joint exercises, especially those which load the spine (for example, the deadlift, squat, clean) are seen as more ‘functional’. This is because they involve stabilisation of posture while performing the technique, and can help with working the core muscles needed for correct postural alignment.