Stretching a muscle with a full range of motion is necessary for optimal muscle growth.
PARTIAL REPS HYPERTROPHY WORKOUTS TO START GROWING SUMMARY
- · When using partial reps hypertrophy workouts, it’s best to train with long muscle lengths.
- When performing bodyweight exercises to build strength, such as push-ups, use a full rep that maximally stretches the chest muscle by placing your arms on elevated blocks.
- Free weight allows for a greater range of motion and greater muscle stretch.
- Partial reps seem to work best for the arms, not the legs.
- Most research supports using a full range of motion that maximally stretches the muscle for muscle growth.
- Stretching a muscle at full length is a potent stimulus for muscle growth.
UPDATE: 4/13-NOT ALL PARTIAL REPS HYPERTROPHY WORKOUTS ARE THE SAME
Several scientists wrote an editorial on the recent literature review suggesting that a full range of motion was superior to muscle growth to a partial range of movements. The team provided literature showing that a partial range of movements in the stretched or lengthened position resulted in similar muscle growth to a full range of motion.
Not all partial rep exercises are the same for building muscle. They wanted to clarify that saying a partial range of motion led to inferior muscle growth, but this is true only with a short muscle position (i.e., muscle contracted position). At long muscle length (i.e., stretched muscle position), partial reps with long muscle length 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 range of motion at short muscle lengths, this superiority disappears when the comparison is made between a partial range of motion at longer muscle lengths versus a full range of motion.”[9]
Length-tension relationship and muscle growth
Tension is important for muscle growth. The range of motion is a crucial factor that determines how much tension a muscle can experience during resistance exercise.
The length-tension relationship of muscle describes how much tension a muscle produces as a function of its length. In layman’s terms, when a muscle is taken through its full range of motion, it allows the muscle to produce high amounts of active tension (i.e., contracting the muscle) and high amounts of passive tension (near the end range of motion).
Why range of motion is important for muscle growth
Range of motion is the degree to which a muscle is actively stretched during a repetition. It has been traditionally recommended to perform a full range of motion with each repetition, so that the muscle is fully contracted, followed by lowering the weight so that the muscle is fully stretched. A partial range of motion or half movement means that the movement does not fully stretch the muscle.
If we think about the tension placed on a muscle, it is equal to the product of reps, weight, and distance.
The most obvious example of this is the leg press. Lifters will load up the leg press until it is full of 45s, lower the weight a few inches, and lift it to a full position. They may use a heavier weight, but the total tension placed on the muscle is reduced because the distance the weight has traveled is exponentially smaller than doing a full range of motion.
When using a partial rep, you can handle more weight, so more weight results in greater muscle tension, which means greater muscle growth…right?
Not quite
While it is true that using a heavier weight can result in greater muscle tension, this does not necessarily mean that it will lead to greater muscle growth. In fact, studies have shown that using a full range of motion with a lighter weight can be just as effective for muscle growth as using a heavier weight with a partial range of motion.
This is because the muscle is still able to produce a lot of tension even when it is not fully contracted. In addition, the full range of motion allows the muscle to be stretched, which can help to stimulate muscle growth.
So, if you want to maximize your muscle growth, it is important to focus on using a full range of motion with each repetition. This will ensure that you are placing the maximum amount of tension on the muscle and that you are stimulating all of the muscle fibers.
PARTIAL REPS HYPERTROPHY WORKOUTS BENEFITS
It’s been suggested that using partial reps (i.e., half 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 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 (i.e., long muscles vs short muscles) using a similar weight.
NOT ALL HALF REPS ARE THE SAME
Researchers had subjects complete either triceps extension with a full or a partial range of motion. The weights were progressively increased over eight weeks. The researchers measured metabolic stress, strength, muscle activation, and 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.[1] 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.[2] This suggests that full reps vs half reps performed in the lengthened position can result in equal muscle growth when in the stretched position.
Hold on! Before you start using 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 squat resulted in greater increases in muscle mass than a partial squat. [3,4] No study has examined half rep bench presses, but it can be assumed that the results would be similar. A typical half rep bench press neglects the stretched position, but if you do a half rep bench press at the bottom part and emphasize the stretch, you may see similar results as doing a full range of motion bench press.
FULL REP VS PARTIAL REPS HYPERTROPHY WORKOUTS: WHICH PRODUCES MORE 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.[5] Thus, all lower-body results favor a full range of motion for muscle growth. When you perform a partial squat, you neglect the bottom part, which reduces muscle stretch. Stretching a muscle with a full range of motion is necessary for muscle growth.
PARTIAL REPS HYPERTROPHY WORKOUTS STUDIES
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 range of motion.[6] 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.
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.[7]
Should you incorporate partial ranges of motion into all exercises based on this information? While based on a single study, it highlights the significance of stretching a muscle for muscle growth, even without using a full range of motion.
The study also shows that executing partial reps on a stretched muscle, like beginning leg curls with the hamstrings fully stretched and then doing a partial rep, can achieve results similar to using a full range of motion. Again, this was just one study, but the initial results are exciting, suggesting that partial exercises with a stretched muscle can be effective as a full range of motion.
PARTIAL REPS HYPERTROPHY WORKOUTS KEY POINTS
- When weight training for muscle hypertrophy, it’s best to train with long muscle lengths.
- When performing bodyweight exercises to build strength, such as push-ups, use a full rep that maximally stretches the chest muscle by placing your arms on elevated blocks.
- Free weight allows for a greater range of motion and greater muscle stretch.
- Partial reps seem to work best for the arms, not the legs.
- Most research supports using a full range of motion that maximally stretches the muscle for muscle growth.
- Stretching a muscle at full length is a potent stimulus for muscle growth.
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