Recent Study: Greater increases in muscle growth when training 5 vs 1 d/wk when volume is equated

Study Link


I have formatted this study to be easier to digest by including only the information that I found to be relevant. I then bolded the important bits of that and included some summaries scattered throughout.

It goes: Short summary of the results for those who don't want to read a lot>A more in-depth read of the results>And then highlights of the integrity of the study (subjects, their history, routine, technique, measurements etc.)

Short summary of the findings:

  • Results find that for hypertrophy you may want to include training blocks of higher frequency training where you distribute your volume across multiple days. For example, instead of doing 5 sets of bench press 2x a week, do 2 sets 5x a week.
  • In theory, this increases MPS and allows you to perform your volume with higher quality.
  • Once a week is as efficient as training 5 times per week to maximize strength gains.
  • Higher frequencies elicited a similar strength gain, and significantly greater increase in hypertrophy of upper-body muscles
  • Also, if you want to maximize hypertrophy you must include isolation.
As a side note: This study shows no difference between 6 vs 3 d/wk training regardless of volume.

In conclusion, this study indicates that under volume-equated conditions, there are no additional strength benefits to training muscle groups 6 days per week in resistance-trained men, and that very high training frequencies may, in some cases, hinder muscle hypertrophy.

The training protocol was somewhat short because it lasted only 6 weeks. It is conceivable that results would have differed with a longer-duration training intervention. We also did not control for nutritional status.

So the sweet spot is potentially 2-3x a week. 5x could still be beneficial over 3x because the 1v5 study had less holes than the 3v6 study and the 3v6 study's holes are pretty big.

Results


  • The current study aimed to compare the effect of a split training routine with muscle groups trained once per week vs. whole-body training routine with muscle groups trained 5 days per week
  • The findings of this study demonstrated that training a muscle group only once a week is as efficient as training 5 times per week to maximize strength gains.
  • The findings of this study suggest a potential hypertrophic benefit to a higher frequency of training when training volume (number of sets per muscle group) is equated between conditions.
  • This would suggest that the increased muscle mass achieved in TOTAL did not translate into greater strength gains.
  • MBI showed that clinical difference between groups for MTTB was unclear. In combination, these data provide evidence that resistance-trained individuals benefit from including periods of training muscle groups more frequently than 1 sessions·wk−1 when the goal is to maximize muscle hypertrophy.

References a separate study [sup][sup][sup][sup][sup][sup]Summary[/sup][/sup][/sup][/sup][/sup][/sup] [sup][sup][sup][sup][sup][sup]Under[/sup][/sup][/sup][/sup][/sup][/sup]​


  • In short: You should do isolation. You may also want to do isolation on a higher frequency with volume distributed.

Back to this study


  • It, therefore, can be speculated that performing fewer sets per muscle group per session may be more effective at reducing prolonged neuromuscular fatigue and allowing the same muscle group to be trained more frequently.
  • In short: Higher frequency with volume distributed = more MPS and ability to perform said volume with better performance and thus net a better response from your training.

Subjects:

  • Eighteen healthy men (26.4 ± SD 4.6 years [range 18 to 30 years]; 177.8 ± 6.6 cm; total body mass = 84.4 ± 8.1 kg; RT experience = 6.4 ± 2.4 years)
  • Subjects were well trained;
  • All had been performing RT a minimum of 3 days to weeks for at least 1 year.
  • The range of RT experience was 2–10 years. All subjects regularly performed (minimum frequency of once a week) all exercises used in the training intervention and in the strength tests for at least 1 year before entering the study. Moreover,
  • subjects were free from any existing musculoskeletal disorders, history of injury

Resistance-Training [sup][sup][sup][sup][sup]RT[/sup][/sup][/sup][/sup][/sup] Program

  • The RT protocol consisted of 25 exercises targeting each of the major muscle groups.
  • all subjects performed the same exercises and similar repetition volume throughout the duration of the study.
  • The external load was adjusted for each exercise as needed on successive sets to ensure that subjects achieved failure in the target repetition range.
  • The RT protocol for both groups consisted of 5 weekly sessions performed on consecutive days (Monday–Friday) for 8 weeks.
  • Subjects performed 3 sets per exercise for a total of 15 sets per session. Each set involved 10–12 maximum repetitions 8 (RM) with 60 seconds of rest between sets and 120 seconds between exercises

    [sup][sup]*[/sup][/sup] All sets were performed to the point of momentary concentric muscular failure and defined as the inability to perform another concentric repetition while maintaining proper technique.

  • All routines were directly supervised by research assistants to ensure proper performance and technique of the respective routines.
  • Adherence to the program was 100% for both groups.

Estimate of Food Intake

  • In short, they made sure to control for dietary intake.
  • Subjects were advised to maintain their customary nutritional regimen and to avoid taking any supplements during the study period.
  • From another section:

Criterion Measurements: Muscle Strength

  • This section re-iterates the points from above and heavily describes the form and technique for the lifts. Mentions they did a 5min warm up beforehand, that they didn't exhaust themselves the day before the lifts, how failure and 1rm was measured. That they achieved 1rm without injury. They even recorded foot and hand placement to have consistency session to session.
  • The sequence of maximum strength tests was 1RMBENCH, 1RMSQUAT, and 1RMROW with a 20-minute rest period separating tests.

Muscle Thickness [sup][sup][sup]MT[/sup][/sup][/sup]


  • Ultrasound imaging was used to obtain measurements of MT.
  • In an effort to help ensure that swelling in the muscles from training did not obscure results, images were obtained 48–72 hours before commencement of the study and after the final training session. This is consistent with research showing that an acute increase in muscle thickness returns to baseline within 48 hours after an RT session (21).

 
@great_depression Super interesting. Does this imply that traditional thinking about rest days is wrong? If you were training one group five times in a week there’s no opportunity to rest that muscle in between.
 
@hisgras It should be noted that this is with people that are trained and the volume was distributed.

So instead of accumulating a lot of muscle damage and fatigue in one session that would require rest days in between, you are simply dividing your volume across multiple days so that it is low enough to basically recover over night. The subjects in this study also had two full rest days. So recovery is properly managed.
 
@great_depression It kinda reminds me of Mike Israetels suggestion of high frequency training of some muscle groups like side and rear delts. They don't take too much damage due to its structure and they can heal pretty quickly so diving lots of volume throughout the week might be better for them due this reason. Actually I have implemented rear/side delt work to my lower body days for this reason so I would be hitting both rear and side delts twice a week. My split is 4 day U/L split by the way. It's too early for me to say it works at the moment but it definitely worth trying since theoretically it makes sense.
 
@lupo Eversince I heard mike say it, post every workout I test my side rear delts and calves and if recovered I hit them 3-6sets of 8-12 reps.

Have seen quality gains aka defined rear delts.. calves still a long way to go
 
@lupo This is what I was thinking when I read that they measured forearm and quad thickness in the studies summary, both muscle groups that respond favorably to high frequency in my experience
 
@great_depression The groups had the same daily and weekly volume, correct? So say group A did something like

Monday: bench 6x8

Tuesday: squat 6x8

Where group B did something like bench and squat 3x8 for monday and Tuesday? Ijust pulled the exercises and numbers out of my ass as an example
 
@hisgras 6 day PPLs have always been seen well so mandatory multi day per week rest days are definitely not needed. Until the science gets better the general advice is "rest as much as you feel you need it" in terms of mental and gym performance
 
@great_depression "Each set involved 10–12 maximum repetitions 8 (RM) with 60 seconds of rest between sets and 120 seconds between exercises"

If they're able to perform a quality set after only 60 seconds rest than you could argue they weren't working intensely enough. This is possibly why they were able to do 15 sets per session 5 days a week.

Anyone trying this with sufficient intensity will not last 8 weeks.
 
@dawn16 Intensity is not just about what %1RM is being used. Reducing the rest time is one way to increase intensity as is adding reps, increasing sets, increasing weights, slower reps, etc. My friend used 45-1 minute rest times and made great progress and he worked each bodypart once per week just like this study features.
 
@braveheart0547
Intensity is not just about what %1RM is being used.

It is though. That's what intensity in this context means.

Still, you're not wrong that you can create an intense workout by manipulating other variables like RPE, volume, tempo, density, etc.
 
@levit7 Context isn’t different. %1RM isn’t the only way to manipulate intensity of an exercise. The %1RM or RPE is often what people refer to by saying intensity since it’s a measurement of intensity, but rest time reduction or inflation can change the intensity of an exercise just as much as the load.
 
@braveheart0547 You're completely missing the point.

Intensity can be and is literally defined as the percentage of 1RM. Your 1RM is 100% intensity. Your 5RM is ~85% intensity.

And as I already agreed with, you can still have an intense workout at low(er) intensities by manipulating other variables.

The context is the difference and it's quite clear from the original comment which meaning of the word he was using.
 
@levit7 In the comment I originally replied to, rest time was a major factor of overall quality of sets so context is relevant but ok. Intensity is actually literally defined as the difficulty of the work you are doing and short rest times is one of many ways to define the difficulty. Mayo Clinic even says that.
 
@dawn16 Exactly my thought also: what about intensity? Is the implication that each set has max intensity? In that case Dorian Yates provides a good data point of less volume and maximum intensity, but he didn’t train as frequently as the study suggests because rest periods were a large part of his training strategy.

If the muscle is truly challenged and therefore fatigued, training it as often as the study suggests would mean training while the damage still exists because muscle doesn’t heal that fast.

This is very interesting to think about and, maybe, our training method of splitting body parts is flawed.

It would be best if we had truly longitudinal data...trained subjects using this methodology for a long time, years. Then compare that to a control group with equivalent volume, diet, age and lifestyle in a traditional split plan.

I suspect (meaning I have only anecdotal data) that the maximum intensity required for optimum hypertrophy at a high frequency but low set volume per day will not allow sufficient healing, damaging muscle that is already damaged worse with each session. Doesn’t that kind of training have to lead to injury and unhealthy muscle fibers?
 
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