Training frequency as a parameter for hypertrophy training is currently the topic of several very good reviews and studies. By overlapping experience and scientific data we can therefore use these as a roadmap to help plan training. Brad Schoenfeld, the expert in the area of hypertrophy, dedicated his presentation at the Dymatize camp to answer exactly this question: which frequency optimises muscle growth – the current scientific stand. We want to summarise his insights for you.
What exactly do we mean by training frequency?
Training frequency typically describes the amount of training sessions in one week. However, this also includes how often a muscle group is trained in one week – and that is the exact question here.
How long do muscles recover after training?
A theory supporting higher training frequencies is that the Muscle Protein Synthesis (MPS), i.e. the growth of the muscle, is elevated for a certain time period of time following training. Therefore, a higher frequency could lead to a continuous elevation in MPS.
This observation can be based on findings from a study by Stuart Philipps et al. (1). In this study (among other factors) they examined the MPS after strength training one arm in isolation. After 48 hours the muscles of all participants were fully recovered. This is in line with findings from a study by Mac Dougall, J. Duncan et al. (2), where the MPS was mostly complete after 36 hours. The trained arm did not show a higher level of protein synthesis than the non-training arm – in four out of six participants. This fairly large difference points towards a highly individual recovery rate, as two out of six participants did not have an elevated MPS. It is also interesting to note that all the participants had training experience, and these showed a peak in MPS after 24 hours in comparison to Philipps, who found a peak after three hours in untrained participants.
The disadvantage of volume
The muscles only do what the nervous system tells them. As the nervous system tires during the session the efficiency of our training decreases and less volume can be completed; especially as the quality further decreases with an increase in fatigue. This leads to the assumption that the distribution of the training volume over several sessions allows a higher weekly volume without a drop in intensity, i.e. quality. Or plainly put: if you train a muscle group on several days, you’ll do less during an individual session but if you take all sets combined, you’ll potentially manage more in one week without a loss in training quality.
Precisely this leads us to the question: whole-body training or split training?
And exactly this question is answered for us by Brad Schoenfeld. The advantages of whole-body training are a higher frequency per muscle group with altogether fewer sessions, whereas split-training allows for a longer recovery period.
The first study examining this is actually delivered by Brad Schoenfield himself, in collaboration with his research colleagues (3). In this study the training of 2 groups was divided differently into a three-day-split and once into three whole-body training sessions. Both groups did the same amount of sets and reps (volume matched) and used the same exercises.
The results showed a small advantage for the group with the higher training frequency (whole-body training). However, there are two points to consider:
- All subjects came from a split-training plan. Therefore, just changing the type of training can lead to a new stimulus. Therefore, the question remains whether the results would also occur in those that are used to whole-body training.
- As the split-training method allows the possibility of a higher volume and in this study the volume was matched, it is possible that the results are skewed in favour of the whole-body training.
In a review by Schoenfeld, Ogborn und Krieger (4), ten studies looking to answer this question were examined. Although the initial findings indicated that there was a small advantage for a higher training frequency, it couldn’t be ascertained whether it’s better to train a muscle group two or three times per week, as there were no studies examining this. It was however clear that a frequency of twice per week per muscle group was better than just working them out once a week.
In order to continuously progress muscle growth, you need to continuously do more; at least this was the traditional viewpoint. But what would happen if you’d rather train a muscle more often to effectively keep the muscle growth going, instead of continuously doing more. The research group of Scott J. Dunkel (5) looked into this and found that after a certain point more sets don’t add any more improvements. Therefore, the frequency as a variable becomes more important the more experienced one is. So, we know that training with three sets is superior to training with one set (6), but what happens when you do even more sets is not yet known.
Naturally at this point the Norwegian Frequency Project was used as reference. Here the training of a group of experienced powerlifters in one group was spread over 6 days, whereas the comparison group did the same volume in three days. The results showed a clear advantage in relation to the hypertrophy of the quadriceps muscle for the training group with the high training frequency. The main issue with this data is that the study never got published. As a result, quite a few questions remain unanswered and a proper evaluation of the results is not possible.
The search continues and the study from Oklahoma State University (7), as well as a study by the research group lead by Saric (8), which both Schoenfeld and James Krieger also worked on, examined the difference between three and six training sessions per week. Both did not find a significant advantage of a higher frequency in relation to body composition or hypertrophy.
A further meta-analysis – a review of the currently available studies – by Schoenfeld, Grgic and Krieger (9) confirmed these findings. Even after looking through 25 studies they couldn’t find any evidence to show an advantage of a higher frequency with the same volume.
Like always in strength training, genes surely also play a large role in this and therefore Schoenfeld conducted a study (10) that shows exactly this: some react better to a higher frequency and others work better with a lower frequency.
So, what should we do now?
Frequency alone is not the decisive variable in hypertrophy training, even if it is advantageous to train a muscle group at least twice per week. The volume of training remains the key component. But more isn’t always better. Up to a certain point the volume is the driving force to help muscles grow, but at some point, it can become too much. Then more doesn’t help anymore and it leads to overtraining. This lets us conclude that even in hypertrophy training the training periodisation plays an important role. It certainly makes sense to increase the volume over several blocks, and then to take a step back and recover during a lower training volume phase and to resensitize. Exactly during this phase training frequency can play an important role.
According to the volume recommendation from James Krieger of 8-10 sets per muscle group, per training session, Brad Schoenfeld now demonstrates how you can increase the volume over phases of different training frequencies:
Block 1: whole-body training with 8 exercises and three sets each for the 3 training sessions per week. That amounts to 72 sets per week (8 exercises x 3 sets x 3 days).
Block 2: upper body / lower body split with two sessions for the upper body and two for the lower body. Here we complete 8 exercises each in three sets as well, and that amounts to 96 sets per week (8 exercises x 3 sets x 4 days).
Block 3: here the frequency is lowered again, and a split introduced. This trains:
Day 1: chest, shoulder, biceps
Day 2: lower body
Day 3: back, biceps, abs
Over 6 days with the same number of sets and exercises this adds up to 144 sets per week (8 exercises x 3 sets x 6 days).
The interesting thing is that even when the training sessions increase from block to block, the total time for all training sessions that are carried out in one week stays the same. Only the number of sessions increases, but these don’t last as long.
The exercises, training and/or nutritional information and recommendations presented in this article/video are to be followed at your own risk and do not substitute personal and/or individual advice. Medical advice should be obtained beforehand by anyone under 18 years of age, by individuals with health restrictions (especially orthopaedic or internal complaints/conditions), and by women who are pregnant or breastfeeding. If problems are encountered when applying the training and nutritional methods, a doctor should always be consulted immediately. No liability is assumed by Active Nutrition International GmbH.
Author: Sebastian Kaindl
Headcoach Kaindl Athletic System
Powerlifting National Coach
Dymatize Scientific Advisory Board Member
- Philips, Stuart M.;et al. „Mixed muscle protein synthesis and breakdown after resistance exercise in humans.“ American journal of physiology-endicrinology and metabolism 273.1 (1997): E99-E107.
- MacDougall, J. Duncan, et alt. „The time for elevated muscle protein synthesis following heavy resistance exercise.“ Canadian Hournal of applied physiology 20.4 (1995): 480-486
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- Schoenfeld, Brad J.; Ogborn D.; Krieger J.W.; „ Effects of Resistance Training Frequency on Measures of Muscle Hypertrophy: A Systematic Review and Meta-Analysis.“ Sports Med (2016) 46:1689-1697
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- Saric, Juraj; Lisica, Domogoj; Orlic, Ivan; Grgic, Jozo; Krieger, James W.; Vuk, Sasa; Schoenfeld, Brad J.; „ Resistance Training Frequencies of 3 and 6 Timer Per Weeek Produce Similar Muscular Adaptations in Resistance-Trained Men.“ J. of Strength& Cond. Res., July (2019), Vol. 33, Issue, S122-S129
- Brad Jon Schoenfeld, Jozo Grgic & James Krieger (2019) How many times per week should a muscle be trained to maximize muscle hypertrophy? A systematic review and meta-analysis of studies examining the effects of resistance training frequency, Journal of Sports Sciences, 37:11, 1286-1295, DOI: 1080/02640414.2018.1555906
- Damas, Felipe; Barcelos, Cintia; Nobrega, Sammy R.; Ugrinowitsch, Carlos; Lixandrao, Manoel E.; Santos, Lucas M.E. d.; Conceicao; Miguel S.; Vechin, Felipe C.; Libardi, Cleiton A.; „Individual Muscle Hypertrophy and Strength Responses to High vs. Low Resistance Training Frequencies“; J. of Strength&Cond. Res., April (2019); vol 33, Issue 4; 897-901