Training with a full and partial range of motions may help result in greater strength gains than a full range of motion alone. Eccentric partials may be a viable partial range of movement that increases muscle growth, similar to a full range of motion lifts.
PARTIAL REPS [CERTAIN TYPES] CAN INCREASE MUSCLE GROWTH THE SAME AS A FULL RANGE OF MOTION SUMMARY
- Training with a full range of motion and partial reps may help result in greater strength gains than a full range of motion alone.
- Eccentric partials may be a viable partial range of movement capable of increasing muscle growth, similar to a full range of motion lifts.
FULL RANGE OF MOTION VS PARTIAL REPS
Normally, when you see a person in the gym doing a partial rep, one immediately thinks of “ego lifting” and someone who is trying to use a weight that is too heavy that he can’t lift thru a full range of motion (FROM). Range of motion is the degree to which a muscle is actively stretched during a repetition.
It has been traditionally recommended that you perform a FROM with each repetition, so the muscle is fully contracted, followed by lowering the weight so the muscle is fully stretched. A partial range of motion or half movement means that the movement does not fully stretch the muscle. If you think about the tension placed on a muscle, it sets x reps x weight and distance.
PARTIAL REPS FOR STRENGTH GAINS
Several studies have found that combining a FROM with a partial reps can result in a greater increase in strength than just doing a full range of motion.
Study 1: Researchers assigned subjects to either a FROM squats or a full range of motion plus partial reps. 1 RM squat increased by 5.1% in the full squat and 8.2% in the full and partial squat combined. There was a trend for the full and partial rep squats to result in greater 1 RM gains.(1)
Study 2: Researchers assigned subjects to either to use a FROM deadlift or a full range of motion plus partial reps (100% -120% of a 1RM). The subjects were well-trained, and they had to be able to deadlift at least 315 pounds to be enrolled in the study. Neither group had a statistically significant increase in the 1 RM deadlift. 1 RM deadlift decreased by -2.7% in the full deadlift and increased by 2.3% in the full and partial deadlift combined.
The author hypothesized that if the full and partial groups kept on their projectory strength gains after 12 weeks, the gains would have been a 4.6% increase, making it a statistically significant increase(2) A few limitations of the study were that the subjects were NCAA wrestlers who were cutting down on calories for competition, and the study was only six weeks.
RESULTS
In these two studies, the groups using full and partial reps trained at a higher intensity because they could use more weight with the partial range of motion lifts. Some suggest that partials can help a lifter get stronger in the “sticking point.” The sticking point is the movement region in the upward range of motion when the vertical bar velocity slows down or stops. The ability to complete a lift becomes more difficult at the sticking point.(3)
Both studies found minor increases in strength with partial and full reps, but if you are a competitive strength athlete, it may be worth incorporating some partials into your routine with some full range of motion movements.
CERTAIN TYPES OF PARTIAL REPS INCREASE MUSCLE GROWTH
It’s been suggested that using partial reps allows more weight, increasing muscle growth; the greater tension causes a compression-like effect on the muscle, creating metabolic stress. Different muscle fibers are activated by stretch when you perform a full range of motion. Although most people perform partial reps using a much heavier weight, researchers wanted to see the effects of a full range of motion vs. a partial range of motion using a similar weight.
STUDY
Researchers had subjects complete either triceps extension with either a full or a partial range of motion. The weights progressively increased over eight weeks. The researchers measured metabolic stress, strength, muscle activation, and muscle growth. At the end of the study, partial reps resulted in greater metabolic stress, muscle activation, and muscle size than a full range of motion in the triceps.(4) Another study found that biceps muscle growth was similar between full (9.7%) and partial reps (7.8%), despite the full range of motion groups using 36% lower training volume.(5)
Hold on! Before you use partial reps for every exercise, these were just two studies. These were both single-joint exercises (triceps extensions and bicep curls). What about multi-joint exercises, such as the squat or bench press? A full range of motion resulted in greater increases in muscle mass than partial movements for the legs.(6, 7)
STRETCHING AND MUSCLE GROWTH
A 2020 meta-analysis found a full range of motion resulted in more growth in four studies (three lower body and one upper body), growth was similar between the partial and a full range of motion in one lower body study, and one upper body study found more growth with partial reps.(8) Thus, all lower-body results favor a full range of motion for muscle growth. If you think about a partial squat, the bottom part of the squat is completely neglected, which results in less stretch on the muscles. Stretching a muscle with a full range of motion is necessary for muscle growth.
A 2021 meta-analysis examining 16 published studies reported that a full range of motion results in more muscle growth and strength improvement in the legs than a partial reps.(9) One study found that when examining muscle growth responses in the leg extension, performing partials with the muscle stretched in the bottom portion of the leg extension, a full range of motion, and a full range of motion and partials combined resulted in similar muscle growth responses in the legs.
PARTIALS REPS
The key takeaway from this study is that muscles stretched at long muscle lengths, despite being a partial rep, can cause similar hypertrophy to a full range of motion training.(10) Does this mean you should use partial ranges of motion for all exercises? This is just one study, but it suggests that stretching a muscle is extremely important for muscle growth, even if it is not taken through a full range of motion.
The study also suggests that doing partials with a stretched muscle, for example, when doing leg curls having the hamstrings fully stretched at the beginning of the movement and then using a partial rep, can be effective as a full range of motion. Again, this was just one study, but the initial results are exciting, suggesting that partial reps with a stretched muscle can be effective as a full range of motion.
NOT ALL PARTIAL REPS ARE THE SAME
Several scientists wrote an editorial on the recent review of the literature suggesting that a full range of motion was superior to muscle growth to a partial reps. The team provided literature showing that a partial reps in the stretched or lengthened position resulted in similar muscle growth to a full range of motion. They wanted to clarify that saying a partial range of motion led to inferior muscle growth, but this is true only with a shortened muscle. At longer lengths, partial reps can provide a similar muscle growth response.
The researchers stated, “In summary, while investigations often report greater hypertrophy of full range of motion training when compared to a partial reps at short muscle lengths, this superiority disappears when the comparison is made between a partial reps at longer muscle lengths versus a full range of motion.”(11)
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