Building muscle requires consistent strength training over time to achieve noticeable gains. But how often should each muscle group be trained weekly to maximize muscle growth? Is a five-day split to train each muscle group once weekly effective?
Past research has shown mixed results; some suggest increased training frequency to support muscle gains, while others counter. A new study published in SportRxiv investigating training frequency might reshape our understanding.
The recent meta-analysis explored the relationship between weekly training frequency and muscle growth, investigating how training a muscle multiple times per week affects growth when the total number of sets for that muscle remains consistent. (1)
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New Data
Consider completing nine sets for the biceps across three different exercises:
- Biceps Curl
- Preacher Curl
- Incline Curl
Training once per week would require completing all nine sets in a single session. Training three times per week would allow nine sets to spread across the three sessions. The key is to keep the total weekly sets equal to isolate the effects of training frequency.
In the study, participants performed their sets to or very close to failure within a specific rep range. The researchers adjusted the training loads to ensure participants consistently reached failure within that range, exploring the best way to measure training frequency.
They distinguished between direct and indirect sets. Direct sets target a specific muscle as the primary force generator (e.g., biceps when curling). Indirect sets involve the muscle as a secondary contributor (e.g., biceps when rowing).
Methods for Counting Training Frequency
The House of Hypertrophy explained three ways to measure training frequency:
- The Total Method: Counting all sets equally.
- If one rows on Monday and performs biceps curl on Thursday, biceps are trained twice weekly.
- The Fractional Method: Assigns partial value to indirect sets.
- Indirect sets count as half a set. Using the same example of rows and biceps curls, the biceps would have a training frequency of 1.5 times per week.
- The Direct Method: Only counts direct sets, ignoring any indirect activation.
- In this case, the biceps would only have a training frequency of once per week.
Research has shown that the fractional method is the most accurate in interpreting training data.
Training Frequency & Muscle Hypertrophy
The study found no significant or consistent effects of frequency on outcomes. However, there was a noticeable improvement when frequency increased from zero to once per week, with a smaller, less impactful improvement observed when increasing from once to twice per week.
These findings align with previous research indicating comparable levels of hypertrophy between split and full-body training programs. (2) Additionally, the study doesn’t demonstrate significant differences in outcomes between trained and untrained individuals.
Interaction With Set Numbers?
Concerns about the research methodology have been raised, mainly regarding the use of too many sets, which may have hindered recovery in the higher-frequency groups. Critics argue that higher training frequencies could yield better results if recoverable training volumes were used.
In response, the researchers categorized the studies into two groups: those applying recoverable volumes and those using unrecoverable volumes.
For the recoverable volume group, participants training a muscle three times per week were limited to a maximum of three sets per session for that muscle. Those training a muscle twice weekly were capped at five sets per session. Participants who trained a muscle once per week performed twelve sets.
Despite these adjustments, the findings didn’t prove that higher training frequencies were superior under either recoverable or unrecoverable volumes. However, too much training volume in a single session could pose the risk of overtraining.
How To Approach Traning Frequency
Ultimately, the total volume of the sets performed is more critical for muscle growth than training frequency.
If volume is high, spread out sets over multiple sessions to avoid overtraining. Dividing the total training volume across multiple days each week is more practical and beneficial for performance and consistency. For example, completing 70 sets over a month instead of one training session is more likely to be effective.
Choosing a training frequency that aligns with one’s personal preferences and recovery capacity is critical. Everyone’s recovery capability differs and training frequency means much less without training consistency.
References
- Pelland, N. J., Remmert, N. J., Robinson, N. Z., Hinson, N. S., & Zourdos, N. M. (2024). The Resistance Training Dose-Response: Meta-Regressions Exploring the Effects of Weekly Volume and Frequency on Muscle Hypertrophy and Strength Gain. SportRiv. https://doi.org/10.51224/srxiv.460
- Ramos-Campo, D. J., Benito-Peinado, P. J., Andreu-Caravaca, L., Rojo-Tirado, M. A., & Rubio-Arias, J. Á. (2024). Efficacy of Split Versus Full-Body Resistance Training on Strength and Muscle Growth: A Systematic Review With Meta-Analysis. Journal of strength and conditioning research, 38(7), 1330–1340. https://doi.org/10.1519/JSC.0000000000004774
Featured image via Shutterstock/seto contreras
