High Load/Low Reps Versus Low Load/High Reps For Hypertrophy

A new study published in the Journal of Physiology shows that neither load nor brief post-workout increases in anabolic hormones determines muscular strength or size gains as long as exercises are performed to momentary muscular failure. While some individuals may respond a little better to higher reps or higher loads, on average a broad range of reps and loads can be effective as long as you train intensely enough. As the authors state in the abstract, “…in resistance-trained individuals load, when exercises are performed to volitional failure, does not dictate hypertrophy or, for the most part, strength gains.”

Morton, R. W., Oikawa, S. Y., Wavell, C. G., Mazara, N., Mcglory, C., Quadrilatero, J., . . . Phillips, S. M. (2016). Neither load nor systemic hormones determine resistance training-mediated hypertrophy or strength gains in resistance-trained young men. Journal of Applied Physiology J Appl Physiol. doi:10.1152/japplphysiol.00154.2016

Abstract

Forty-nine resistance-trained men (mean ± SEM, 23 ± 1 y) performed 12 wk of whole-body RT. Subjects were randomly allocated into a higher-repetition (HR) group who lifted loads of ~30-50% of their maximal strength (1RM) for 20-25 repetitions/set (n=24) or a lower-repetition (LR) group (~75-90% 1RM, 8-12 repetitions/set, n=25), with all sets being performed to volitional failure. Skeletal muscle biopsies, strength testing, DXA scans, and acute changes in systemic hormone concentrations were examined pre- and post-training. In response to RT, 1RM strength increased for all exercises in both groups (p < 0.01), with only the change in bench press being significantly different between groups (HR: 9 ± 1 vs. LR: 14 ±1 kg, p = 0.012). Fat- and bone-free (lean) body mass, type I and type II muscle fibre cross sectional area increased following training (p < 0.01) with no significant differences between groups. No significant correlations between the acute post-exercise rise in any purported anabolic hormone and the change in strength or hypertrophy were found. In congruence with our previous work, acute post-exercise systemic hormonal rises are not related to or in any way indicative of RT-mediated gains in muscle mass or strength. Our data show that in resistance-trained individuals load, when exercises are performed to volitional failure, does not dictate hypertrophy or, for the most part, strength gains.

Unlike many other resistance training studies which use a relatively small number of untrained subjects and tend to only last six to eight weeks this one used forty-nine men with at least two years of previous resistance training experience and lasted twelve weeks, making the results more reliable and relevant to training beyond the beginner stage. The subjects were randomly divided into two groups; a higher rep group that used thirty to fifty percent of their one rep max to perform sets of twenty to twenty-five repetitions, and a lower rep group that used seventy-five to ninety percent of their one rep max for sets of eight to twelve repetitions. Each group performed four brief, full-body workouts per week, consisting of three sets to momentary muscular failure of each exercise:

Monday/Thursday:

  • Leg Press super-setted with Seated Row
  • Bench Press super-setted with Cable Hamstring Curls
  • Front Planks

Tuesday/Friday:

  • Shoulder Press super-setted with Bicep Curls
  • Triceps Extensions super-setted with Wide-Grip Pulldowns
  • Leg Extensions

I would have preferred the subjects perform only one set to failure and combine the exercises into two longer full-body workouts instead of the four shorter ones. Since most other studies show no significant difference in muscular strength and size gains between single and multiple sets or when performing more than two or three full-body workouts per week, this would have been just as effective but more time efficient.

high load/low reps vs low load/high reps

Results

Over the twelve weeks both groups increased muscular strength on all exercises, with no significant difference except the lower rep group improved slightly more in the bench press. Both groups had hypertrophy in both type I (slow twitch) and II (fast twitch) muscle fiber cross sectional area throughout the body with no significant difference. This confirms that a broad range of training loads and repetition ranges can be effective for improving muscular strength and size if exercises are performed to momentary muscular failure, and disproves the popular belief you must use lighter weights and higher reps to target your slow twitch muscle fibers and heavier weights and lower reps to target your fast twitch muscle fibers. The authors state, “The current data, along with previous work (28, 35), are direct proof that hypertrophy and strength gains are not a function of the load lifted and directly contradict the assertion that acute EMG recordings predict hypertrophic potential (21). Instead, we propose that exercising until volitional failure with adequate volume and load (between 30-90% 1RM) will sufficiently activate muscle motor units, which drives skeletal muscle hypertrophy.”

The study also disproves the popular belief that the acute hormonal effects of training with short rest periods or super-setting are beneficial for increasing muscular strength and size. They state, “post-exercise levels of circulating hormones did not change as a result of the RT intervention were unrelated to, and did not account for significant changes in, muscle mass or strength” and “In agreement with previous studies (50-52) it is clear that the post-exercise increases in systemic hormone concentrations are unrelated to changes in muscle hypertrophy or strength.” So rushing between exercises to increase growth hormone will not improve muscular strength or size gains as if often claimed, although it might still be beneficial for cardiovascular conditioning. I now question this as well, since research comparing sprint interval training with traditional endurance training shows it is not necessary to maintain a high metabolic demand and elevated heart rate continuously for this purpose.

Implications for training

While this shows a broad range of loads and repetitions can be effective there will be a point of diminishing returns below some level of load and above some time under load, and you should not expect to get the same results if you perform hour-long sets to failure using a very light weight. There is no mention in the study of the repetition cadence used so the exercises were most likely performed at typical speeds, meaning the high repetition sets probably did not exceed ninety seconds, and we can’t assume the same results using sets that are much longer than this. Also, while a broad range of repetitions can be effective on average, the optimal repetition range for some individuals may be lower or higher and may even vary between muscle groups and you should experiment and adjust your rep ranges or time under loads accordingly.

It should also be noted that while either low-load/high-rep sets or high-load/low-rep sets or anything in between can be effective for improving general muscular strength and size it is still necessary to perform specific high-load/low-rep sets to improve maximal strength in specific lifts (e.g. for increasing bench press or squat 1RM for competition) due to neural adaptations: “Though there is no apparent advantage of lifting with different loads on changes in muscle mass, there is undoubtedly a neuromuscular advantage to lifting heavier loads if the primary outcome is performing a 1RM test (28). Conversely, it appears that periodic practice of the chosen strength outcome (e.g. 1RM) is effective at eliminating the majority of any post-training difference.” For example, while low-load/high-rep sets to failure can improve your strength for powerlifting, you would need to increase the weight and reduce the reps on the competitive as you get closer to a contest.

If your goal is to improve your overall functional ability and physical appearance I recommend erring conservatively and using exercise loads that allow you to achieve momentary muscular failure within sixty to ninety seconds as a starting point (for example, six to ten repetitions at a 4/1/4 cadence, four to six repetitions at a negative-emphasized 4/1/10 cadence, or a 60 to 90 second static hold or timed static contraction). Using lower loads can make many exercises safer and using higher reps and a longer time under load can increase the metabolic and cardiovascular conditioning effect while being just as effective for improving muscular strength and hypertrophy.

This study also confirms that bodyweight high intensity training can be just as effective for increasing muscular strength and size as training with weights or machines as long as the method you use allows you to achieve momentary muscular failure within a reasonable time frame. This isn’t surprising, since I’ve been seeing these kinds of results in my bodyweight training clients for the past few years.

If your primary goal is building bigger, stronger muscles, you don’t need to rush between exercises to elevate growth hormone levels. While limiting rest between exercises may be more beneficial for cardiovascular and metabolic conditioning, and it will allow you to complete your workouts faster, doing so does not appear to have any effect on muscular strength and size increases. That being said, resting longer between exercises to increase the loads you are capable of using doesn’t appear to be necessary either. As a general guideline I recommend something in between; rest just long enough between exercises so cumulative systemic fatigue doesn’t interfere with your ability to perform subsequent exercises with a high intensity of effort and to achieve momentary muscular failure due to local muscular fatigue.

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  • Billy May 14, 2016 @ 17:17

    Great information thanks for posting. These conclusions make sense to me, based on my unscientific experience. I especially like how are you correlated to study to bodyweight training. Your info has become a real go-to source for me, keep it coming!

    • Drew Baye May 17, 2016 @ 12:03

      Hey Billy,

      You’re welcome, and as long as people keep reading my articles and books I’ll keep writing them.

      • Claude Apr 17, 2019 @ 11:36

        Bright guy! Without going in the details, in my region, some say I m strongest in arm wrestling and only lift light weights..Seems more natural!

        Claude

  • Mateo May 16, 2016 @ 9:42

    Drew, do you think it is posible to gain muscle mass with isometric training only, assuming a time under tension of 60-90 seconds?

    Thanks.

  • Lifter May 16, 2016 @ 18:54

    What do you make of Holman’s outlook, from this research….
    Appl Physiol Nutr Metab. 2012 Jun;37(3):551-4. Epub 2012 Apr 26.
    Abstract: “It is often recommended that heavier training intensities (?70%-80% of maximal strength) be lifted to maximize muscle growth. However, we have reported that intensities as low as 30% of maximum strength, when lifted to volitional fatigue, are equally effective at stimulating muscle protein synthesis rates during resistance exercise recovery. This paper discusses the idea that high-intensity contractions are not the exclusive driver of resistance exercise-induced changes in muscle protein synthesis rates.”

    • Drew Baye May 16, 2016 @ 19:48

      Hey Lifter,

      Holman isn’t saying anything different. Like most of the fitness industry he is making the mistake of using the term intensity to mean load. What he wrote makes sense when the terminology is corrected:

      “It is often recommended that heavier training loads (?70%-80% of maximal strength) be lifted to maximize muscle growth. However, we have reported that loads as low as 30% of maximum strength, when lifted to volitional fatigue, are equally effective at stimulating muscle protein synthesis rates during resistance exercise recovery. This paper discusses the idea that high-load contractions are not the exclusive driver of resistance exercise-induced changes in muscle protein synthesis rates.”

  • Craig May 17, 2016 @ 7:19

    Mistake? I think it has long been the convention in exercise science to use intensity to means load, or percentage of 1 RM. Only the HIT community uses intensity to mean effort.

    • Drew Baye May 17, 2016 @ 11:08

      Hey Craig,

      The convention is wrong. When people talk about intensity with regards to exercise they mean intensity of effort, or how hard you are working. The conventional use of intensity to mean a percentage of load is based on the assumption that load corresponds to effort, which is wrong because the exact same load can require different levels of effort depending on how an exercise is performed and the effort will change during an exercise, increasing as the target muscles fatigue. For the sake of effective communication the term load should be used when talking about the weight an exercise is performed with (as a percentage of some repetition maximum; 1RM, 10RM, etc.) and the term intensity should be used when referring to the level of effort an exercise is performed with (as a percentage of how hard one is working relative to momentary ability).

  • Marius Jun 4, 2016 @ 1:26

    Hey Drew,

    there is something odd I recently discovered while training with my wife. Doing a chin-up static hold, she can stay in the desired position for twice as long as I can but – while I can do three dynamic chin-ups (4/0/4) – she can do none dynamically. Any thoughts on that?

    • Drew Baye Jun 6, 2016 @ 12:29

      Hey Marius,

      Without being able to observe and compare the exact positions you are performing them in I can’t comment on differences in difficulty due to technique, but one possibility is her ratio of muscular endurance to strength is much higher than yours.

  • Jason Crabtree Jun 5, 2016 @ 10:52

    Hey Drew,

    The beauty of this research and much like it is the scope of variety it gives trainers and trainees. Many trainees prefer and enjoy higher rep ranges with a lower weight, whilst others prefer the heavy loads. As long as they’re going to concentric failure in good form, it matters very little. If using a heavier weight is what motivates the person to train hard, so be it. As Clarence Bass points out.

  • Robert Adams Jul 23, 2016 @ 17:03

    Hi Drew,

    I really appreciate this article. I had read it when you first posted it and thought it was interesting. Then it became useful today when as I am away at a business conference and kind of locked into the hotel (rode with someone else). As we all know, hotel gyms are not the best, but I remembered this article and thought I would try the equipment and see if I could get a good workout.

    The only strength equipment they had was some standard dumbbells up to 50 lb pairs and one of those cross-fit pulley unilateral weight stacks (no idea what they’re actually called). I normally do 5 sets once a week: Nautilus Duo Squat, Nautilus Decline Press, Nautilus Pullover, Nautilus Lateral Raise and a variable resistance non-Nautilus Machine Curl – each with a 5/5 rep cadence using a metronome on my phone to keep reps standardized.

    Today, I used the 50 lb dumbbells for a dumbbell deadlift and varied my time from 5/5 to 15/15 and felt the burn in rep 3 and failed after rep 4. I used the cable pulleys for a dip and pull-down variation doing 5/5 cadence and failing after 6 reps on dips and 12 reps on chins (didn’t change the weight as I was working out with some colleagues who had no idea what they were doing and I just wanted ro get through it and be sociable with them).

    I don’t have the ache in the upper body from a good workout, but as I sit here writing this my legs are still aching an hour later. This, for me, proves a couple of things. First, dumbbells can be a useful tool (I’ve been kind of a Nautilus/MedX/Hammer Strength snob). Second, that the results of the experiment are valid, as my legs feel like they had a Nautilus Duo Squat workout!

    Thanks again for all the great information you post. KBO – Keep Buggering On!

    • Drew Baye Oct 8, 2016 @ 17:43

      Hey Robert,

      You’re welcome. While some equipment is better than others ultimately your results have far more to do with how you train than what equipment you use.

  • Roberto Casanova Aug 18, 2016 @ 18:25

    I wish they had also used a lower rep range (3-5 and/or 5-8 and/or 6-10) for testing. Normally I have seen 8-12 referred to as a moderate range suitable for size and strength (I believe you’ve addressed this elsewhere). But this does seem to point to higher rep bodyweight exercises (e.g. BW Squats 25 reps) as being effective for both strength and size gains.

    • Drew Baye Sep 2, 2016 @ 13:46

      Hey Roberto,

      Higher rep or longer duration bodyweight exercises have turned out to be more effective for increasing muscular strength and size than I’d have thought. You don’t need high reps for a longer time, though. In my bodyweight high intensity training programs the rep ranges usually only go up to twelve, but they are very slow reps, so more aren’t needed.

      • Roberto Casanova Sep 4, 2016 @ 12:58

        I can attest to how brutal BW Squats (and variants like lunges) or Pushups feel when done slowly and emphasising the hardest portion of the ROM. They are definitely not fun and I almost would rather do machine leg presses or chest presses.

  • Eric Ramos Jan 4, 2017 @ 4:11

    Drew,

    You’ve said for a while now that HOW you do an exercise is more important than HOW MANY times you do it. So with that in mind and the fact that hypertrophy can happen with low/high loads, what does this say about progressive overload? Does that mean that getting stronger over time is a sign that hypertrophy is occurring? Progressive overload is not necessarily the goal but a tangible marker that things are going in the right direction? How you do the exercise and finish it off is more important that seeking that extra rep week to week, it happens when it happens as long as performance doesn’t deteriorate.

    You’ve mentioned here, https://baye.com/qa-lagging-exercises/, that sometimes matching your performance indicates an improvement.

    • Drew Baye Jan 7, 2017 @ 9:53

      Hey Eric,

      As you get stronger you need to work against more resistance and/or increase the exercise duration (up to a point) to challenge your muscles enough to stimulate further adaptation. What is important to keep in mind that resistance is the product of many factors other than load and that compromising form to alter those other factors for the sake of using a heavier load or to make a load easier to lift for the sake of more reps is counterproductive when doing so increases the risk of injury.

      This is one of the first things covered in Elements of Form, which I hope to have out soon.

  • William Oles May 31, 2021 @ 16:00

    Just found your website as a result of a google search for “high reps low weight hypertrophy” led me to this article. This is great info, and hopefully good news for me. I’m 60 and got a bowflex to workout trying to stave off sarcopenia in my older age. But trying to work out old school with heavy loads and 8 to 10 reps with little rest like I did when I was a kid hasn’t worked out for me. I’m just to wiped out after a workout to do much, and can’t keep up exercising due to my long recovery times. After reading this, I’m going to go down to lower weights and more reps, and I’m going to combine regular cadence with negative emphasis and static holds on each set for a total of 20 or 25 reps ’til failure. I can’t wit to see how it works, and I’ll be checking out more of the articles on your website for more ideas. Thanks for all you’re doing to spread great info for guys like me.

    • Drew Baye Jun 21, 2021 @ 8:22

      Instead of doing higher repetitions I recommend doing slower repetitions. The time under load of an exercise is far more important than the number of repetitions performed, and slower reps are easier on the joints and allow for better focus on contracting the target muscle groups. I recommend a minimum cadence of 4/4, and better yet, 10/10, for around 60 to 90 seconds as a starting point (some will do better with shorter or longer TUL ranges).