5.4 Range of Motion (ROM)

Full ROM training should be the default for most exercises in most mesocycles. It provides tension across the entire contractile range, trains the muscle at both long and short lengths, and builds mobility alongside strength.

However, ROM is subjective. “Full ROM” means something different for every lifter based on their individual limb lengths, joint structure, injury history, and mobility. For one person, a full‑ROM squat means hamstrings covering calves; for another with long femurs and a deep hip socket, it means parallel. Do not force a ROM that your anatomy does not support—the tension drops off when you lose position, and the injury risk rises. Train through the range of motion you can control with the target muscle under tension. If that means a slightly shorter ROM than the person next to you, so be it. The tension is what matters, not how the movement looks. This is also why cues like ATG (ass to grass) are unhelpful and potentially harmful.

Lengthened partials (partial ROM in the stretched half) have been shown to produce at least equivalent hypertrophy to full ROM in several studies [1,11], but the totality of evidence suggests that:

• Full ROM produces robust hypertrophy across all studies.
• Lengthened partials can be used as a supplement when you want to emphasize the stretched position or cut out portions of the ROM of an exercise that are not very productive (e.g., the top part of a dumbbell press, where the torque on the pectorals is reduced)
• Shortened partials are inferior for hypertrophy and should not be a regular mainstay unless specifically prescribed for a purpose (e.g., overloading the lockout in a powerlifting peaking phase).

In the context of the Two‑Exercise Rule (4.3.2), ROM is already addressed: the lengthened‑emphasis exercise covers the stretched range; the shortened‑emphasis exercise covers the contracted range. Full ROM for both exercises naturally covers the middle. If only a single lengthened exercise is used, full ROM still ensures all sarcomeres are trained, thus that should be your goal.