Lengthened Partial Reps Cause Same Amount of Hypertrophy as Reps at Full ROM, Says Study
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
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.
The Methods
30 healthy resistance trained participants took part in the study
A mixed sample of participants was targeted, with emphasis on those with more training experience
Each of their arms were assigned to either lengthened partials or full range of motion
The participants took part in an 8-week training programme
They trained twice a week and each session consisted of four exercises, with four sets per exercise
Resistance training programming was as follows:
Day 1: Flat machine chest press, 4 x 5-10; bench dumbbell row, 4 x 10-15; dumbbell overhead tricep extension, 4 x 10-15; dumbbell supinating curl, 4 x 10-15
Day 2: Incline machine chest press, 4 x 10-15; cable single arm pulldown, 4 x 5-10; cable pushdown, 4 x 5-10; Bayesian curl, 4 x 5-10
After a familiarisation period, the participants completed on each arm:
Full range of motion: sets to failure of full range of motion for all reps
Lengthened partials: sets to failure of 50% of the rep at the lengthened portion of the rep
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.'
Muscle hypertrophy of the elbow flexors and extensors were measured using ultrasonography. Strength endurance was measure via testing 10 rep max on the lat pull down.
The Results
Both lengthened partial reps and full range of motion training produced similar increases in muscle thickness (45% and 55% of the humeral length). The analysis method (Bayesian analysis) provided moderate support for the hypothesis that there was no significant difference between the two training approaches in terms of muscle growth.
Improvements in 10-rep max strength endurance (both partial and full ROM) were also similar between the LP and full ROM protocols.
The Conclusion
The study concluded that both lengthened partials and full range of motion training produce similar muscle hypertrophy and strength endurance adaptations in resistance trained individuals. For individuals aiming to maximise muscle hypertrophy and strength endurance, both lengthened partials and full ROM exercises appear to be equally effective.
The results emphasise the importance of training muscles in a lengthened position. Whether trainees use full range of motion or lengthened partial repetitions, focusing on this phase appears to be key for muscle growth.
What Does This Mean for Us?
We can opt for either lengthened partials or full range of motion, depending on personal preferences, individual needs, and available equipment, as long as the muscle is trained in a stretched position.
Since the study involved participants with substantial training experience, it's crucial to choose a range of motion that aligns with your own experience and biomechanical limits. For example, while we often joke about squatting 'ass to grass' (ATG), it’s not suitable for everyone. In fact, some people may benefit more from a reduced range of motion that better matches their mobility and strength levels.
Despite the small sample size, this study contributes to the growing evidence suggesting that training muscles at longer muscle lengths (whether that's by lengthened partials or full range of motion) may be key for maximising muscular hypertrophy.
Citation: Wolf, M., Androulakis Korakakis, P., Piñero, A., Mohan, A. E., Hermann, T., Augustin, F.,Sappupo, M., Lin, B., Nippard, J., Swinton, P. A., & Schoenfeld, B. J. (2024). Lengthened Partial Repetitions Elicit Similar Muscular Adaptations as a Full Range of Motion During Resistance Training in Trained Individuals. SportRχiv.
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