Range of motion (ROM)

Range of motion (ROM) is the measured movement around a specific joint or body part.^{1International Sports Sciences Association, Fast Track Study Guide: Program Design and Implementation, p. 8.} Flexibility is the ability to move a joint through its complete, pain-free ROM; because it’s joint specific, no single test can rate it for the whole body.^{2Ozemek et al., ACSM’s Guidelines for Exercise Testing and Prescription, 12th ed., p. 248.} Testing uses a goniometer or inclinometer to measure degrees of movement after a general warm-up and static stretching, taking the best of three trials.^{3Ozemek et al., ACSM’s Guidelines for Exercise Testing and Prescription, 12th ed., p. 250.}

ROM is also a training variable: muscle activation changes through a movement, so full-ROM exercises should form the base of a hypertrophy program.^{4Schoenfeld, Science and Development of Muscle Hypertrophy, 2nd ed., p. 136.}

In practice

Train through the full range the client has available.^{5Helms et al., The Muscle & Strength Pyramid: Training, 2nd ed., p. 165.} Bone structure and soft tissue differ between clients, and forcing extra depth, such as squatting deeper with a rounded lower back, can be unsafe.^{5Helms et al., The Muscle & Strength Pyramid: Training, 2nd ed., p. 165.}

Studies on squats, biceps curls and leg training found more growth with full ROM, even though partial-ROM groups lifted heavier loads.^{5Helms et al., The Muscle & Strength Pyramid: Training, 2nd ed., p. 165.} Strength from partial reps transfers poorly to the full lift, while full squats build strength in both ranges.^{5Helms et al., The Muscle & Strength Pyramid: Training, 2nd ed., p. 165.}

The stretched position seems especially important for growth.^{4Schoenfeld, Science and Development of Muscle Hypertrophy, 2nd ed., p. 136.} Partial reps can still supplement a program, and their heavier loads may help full-range lifts.^{4Schoenfeld, Science and Development of Muscle Hypertrophy, 2nd ed., p. 136.}