“Full range of motion” is one of the most repeated instructions in strength training, and one of the least examined. It matters for equipment as well as technique, because racks, machines and cable stacks all set limits on how far a joint can travel. A 2020 systematic review by Schoenfeld and Grgic, published in SAGE Open Medicine, looked directly at the question of whether full or partial range of motion (ROM) produces greater muscle growth. This article summarises what that review found, at the strength the evidence supports.
What the review examined
The authors set out to review studies comparing exercise performed through a full range of motion against a partial range in dynamic, longitudinal resistance training programmes, with muscle hypertrophy (growth in muscle size) as the outcome. Six studies met the criteria: four involved the lower limbs and two the upper limbs. The combined sample was 135 participants, of whom 127 were men and 8 were women, and the methodological quality of all six studies was rated “excellent” on the modified PEDro scale. The review’s introduction adds that a majority of research shows strength gains to be specific to the joint angle trained, which is a separate question from muscle size.
Lower body: full range looked favourable
The authors concluded that training through a full range of motion appears to confer beneficial effects on hypertrophy of the lower body musculature compared with a partial range. Three of the four lower-body studies favoured full range. Of the studies using free-weight exercises, two reported that full-range training may produce greater growth in the quadriceps. However, two studies that measured muscle volume with MRI found similar quadriceps results between conditions, and gluteal and adductor growth was greater with full range in a single study, so the authors urge caution about drawing inferences from that finding.
A possible threshold
The authors interpret the data as implying that the benefit applies up to a certain range-of-motion threshold, beyond which the advantage attenuates. They point out that in the study finding no difference for the quadriceps with free weights, the “partial” condition (0 to 90 degrees of knee flexion) was already large compared with the partial conditions in other studies. This is a hypothesis from the authors’ interpretation, not a demonstrated fact.
Upper body: no clear answer
For the upper limbs, the picture was mixed. One study found that partial range produced greater growth in the elbow extensors, while another found modest advantages for full range in the biceps that did not reach the conventional significance threshold. The authors describe the evidence as limited and conflicting, which precludes strong practical inferences, and state that no compelling rationale can be made for a given range in the upper-body muscles. No study to date had examined trunk muscles.
Machines and accommodating resistance
One study in the review used isokinetic leg extension, a form of accommodating resistance in which resistance is maximal throughout the range. Muscle volume changes were similar between full and partial range, and the authors suggest range may matter less with this kind of resistance, provided effort is also maximal. The finding comes from a single study of 11 untrained men, so it cannot be generalised to selectorised machines or cable stacks.
Limits of the evidence
- About 94 per cent of participants across the studies were young men, so results may not generalise to youth, women or older people.
- Only one study included participants with previous resistance training experience.
- The review compared larger ranges against shorter ones; it did not test combining both, though the authors note it is conceivable that combining variations could have synergistic effects, and label this a research gap.
What this means when comparing equipment
The review concerns how exercises are performed, not any particular product, and it says nothing about which brand of rack or machine is better. It does give buyers one practical question to ask of any specification: how far can the joint travel in the exercises intended? Where a listing gives seat, pad and lever adjustment ranges, or the height range of a rack’s pins and safety arms, those figures indicate whether a user of a given height and limb length can train through a large range. Equipment that forces a shortened range on some users would have that effect for reasons of design rather than by choice.
Frequently asked questions
Does full range always build more muscle?
Not according to the review. Lower-body evidence leaned towards full range, while upper-body evidence was mixed, and the authors saw benefits attenuating beyond a threshold.
Is partial range wrong?
The review does not say so. It notes that some upper-body results favoured partial range and that combining range variations remains unstudied.
The bottom line
A 2020 systematic review of six high-quality studies found that training the lower body through a full range of motion appeared to support muscle growth better than a partial range, while upper-body findings were limited and conflicting. The sample was largely young men, few had training experience and the number of studies was small, so the conclusions are provisional. For buyers, the useful takeaway is to check the adjustment ranges that determine how much movement a piece of equipment allows.
Sources
- Schoenfeld BJ, Grgic J, “Effects of range of motion on muscle development during resistance training interventions: A systematic review”, SAGE Open Medicine, 2020 (PubMed Central)
- Schoenfeld BJ, Grgic J, “Effects of range of motion on muscle development during resistance training interventions: A systematic review” (PubMed abstract)