Training volume in the study was more important than training frequency for muscle growth. Training frequency was more important for strength gains than muscle growth.
Most bodybuilders train each bodypart two and sometimes three times a week, but according to a new study, training volume is more important than the frequency for increasing muscle growth. Increasing the number of times you are training a bodypart can raise the training volume, leading to greater muscle growth increases.
A previous meta-analysis found that increasing training frequency could increase muscle strength and muscle size.(1) However, if the volume (sets x reps) is similar, training a bodypart more often will not increase muscle growth, according to a new study.(2) Researchers had three groups of subjects train for four weeks. The subjects performed arm resistance exercises and were assessed for muscle strength and changes in muscle thickness with the different exercise protocols.
The Volume Study
The arm exercise comprised ‘maximal voluntary eccentric bicep contractions’ performed on a machine that measures muscle strength in each muscle contraction you would do at the gym. An eccentric contraction is when you lower the weight. The subjects were placed in one of the three groups with a different number of eccentric contractions in a session and a training frequency in a week.
- Group 1: six maximal eccentric contractions, 1 day per week (6 eccentric contractions X 1 day per week)
- Group 2: six maximal eccentric contractions, 5 days per week, and (6 eccentric contractions X 5 days per week)
- Group 3: five sets of six maximal eccentric contractions, 1 day per week (30 eccentric contractions X 1 per week)
One would expect that the five days per week training would cause greater muscle growth, but at the end of the study, both the once-per-week training with 30 eccentric contractions and the five days per week with 6 contractions per day had similar increases in muscle growth. The 6 X 5 group increased muscle thickness by 10.4%, whereas the 30 X1 groups increased muscle thickness by 8.0%. The researchers noted they suspected that the increases in muscle thickness could be due to true increases in muscle size. However, they did not rule out that this could be swelling from the inflammation response with eccentric exercise.
A certain threshold exists in which exercising a muscle group more often will not further increase muscle growth. A previous study compared two different training frequencies; three versus six times a week, with the same training volume (i.e., sets x reps) in the bench press and squat resistance exercises and reported that the magnitude of increase in muscle thickness of triceps and leg muscles after 6 weeks of the training was similar between the different frequency programs.(3)
Furthermore, a meta-analysis by Schoenfeld found that training frequency did not affect muscle growth when the training volume was similar.(4) This study agrees with both of the above studies, in which training volume was the most important factor for muscle growth rather than frequency.
For strength gains, the five days per week with 6 eccentric contractions had superior increases in strength compared to the once-per-week training with 30 X1. This suggests that increasing exercise frequency may be beneficial for strength gains rather than training a bodypart once per week. The 30X1 group had no increases in strength. The researchers suggested that for those who want to maximize strength gains, performing many eccentric contractions once per week is inferior to performing a smaller amount of eccentric contractions multiple times per week.
This suggests that excessive fatigue from performing 30 maximal eccentric contractions per day could have been the reason for the inferior strength gains in the 6 X 5 group. The researchers stated in the paper, “When the time between sessions is too long (i.e., 1 week), the muscle adaptations produced after one training session may be lost before the next training session; thus, the training effects may not be accumulated. This may be the case for the 6 × 1 and 30 × 1 groups.” These suggest that performing a small amount of eccentric resistance exercise more frequently is a key to increasing muscle strength, or at least such a protocol is beneficial as a starting point.
1. de Souza TP, Jr, Fleck, S. J., Simão, R., Dubas, J. P., Pereira, B., de Brito Pacheco, E. M., da Silva, A. C., & de Oliveira, P. R. (2010). Comparison between constant and decreasing rest intervals: influence on maximal strength and hypertrophy. Journal of strength and conditioning research, 24(7), 1843–1850. .
2. Yoshida R, Sato S, Kasahara K, Murakami Y, Murakoshi F, Aizawa K, et al. Greater effects by performing a small number of eccentric contractions daily than a larger number of them once a week. Scandinavian Journal of Medicine & Science in Sports.n/a(n/a).
3. Saric J, Lisica D, Orlic I, Grgic J, Krieger JW, Vuk S, et al. Resistance Training Frequencies of 3 and 6 Times Per Week Produce Similar Muscular Adaptations in Resistance-Trained Men. J Strength Cond Res. 2019;33 Suppl 1:S122-s9.
4. Schoenfeld BJ, Grgic J, Krieger J. 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. J Sports Sci. 2019;37(11):1286-95.