Lengthened Partial Reps Cause Same Amount of Hypertrophy as Reps at Full ROM, Says Study

This hot-off-the-scientific-press study suggests that taking time at the end of your reps is what pays dividends for muscle growth

Not training with a full range of motion is one of those classic gym faux pas – right up there with not re-racking your weights or doing bicep curls in the squat rack (okay, maybe not quite that bad). However, the evidence is clear: training with full range-of-motion reps is superior for muscle growth compared to half reps, which often keep the muscles in a shortened position (e.g., half-rep squats that don’t break parallel)

There has been a growing body of evidence supporting the efficacy of long length partial reps for muscle growth. In fact, a recent study found that training calves in the lengthened position leads to 43.3% more muscle growth compared to the shortened position. Now, new research has compared the lengthened partial muscle-building protocol against reps completed at full range of motion. Here’s the results.

The study pre-print aimed to compare the effects of long length partial repetitions and full range of motion (ROM) resistance training on muscle hypertrophy and strength endurance. Specifically, the researchers wanted to explore if training in the long length partial position (LLP) elicits similar or different adaptations when compared to traditional full range of motion training.

After a familiarisation period, the participants completed on each arm:

Only the unilateral exercises used one limb as lengthened partial (LP) repetitions and full range of motion (ROM) repetitions.

The study states: ‘The eccentric phase was performed in approximately two seconds, with a one-second pause at the position where the target muscle was at its longest length. The concentric phase was executed with the intent to move the load explosively. Participants rested for one minute when switching to the opposite limb within a set and between sets.’