Does resistance training frequency affect strength and size gains? Original paper

This study had participants perform the same amount of resistance training split into either two or four workouts per week. There was no difference between groups for changes in strength or lean mass.

This Study Summary was published on March 2, 2022.

Background

To optimize the effects of resistance training, manipulating several factors, such as volume, load, and frequency, is central. The American College of Sports Medicine recommends that novice and intermediate exercisers do resistance training for each muscle group two or three times per week, while more advanced exercisers should train one to three muscle groups each session.[1] In contrast, the latest meta-analyses suggest a limited role of training frequency for enhancing gains in muscle strength and hypertrophy (bulk) when weekly training volume is identical between groups.[2][3] However, most of the available studies featured untrained participants and compared one training session per week to three.

The study

In this 9-week randomized controlled trial, 21 moderately trained participants (average age of 26) were assigned to a low-frequency (LF) or high-frequency (HF) resistance training program. The number of weekly sets and training load were identical between groups, but the HF group split it into four workouts per week, while the LF group did the same amount in two workouts per week — meaning that the HF group performed half the training volume of the LF group at each workout.

The outcomes assessed were one-repetition maximum (1RM) for the barbell back squat, hack squat machine, barbell bench press, and chest press machine exercises; body composition, measured by DXA (dual-energy X-ray absorptiometry) scan; and vastus lateralis (the largest quadriceps muscle) thickness, measured by ultrasound. The DXA and ultrasound measurements were taken between 48 and 96 hours after the last training session.

The results

Compared with baseline, both groups improved their 1RM for the barbell back squat, hack squat, barbell bench press, and chest press machine, with no differences between groups. Similarly, total lean mass, lean leg mass, lean trunk mass, lean arm mass, and vastus lateralis thickness improved in both groups, with no differences between groups.

Note

A strength of this study is that all of the workouts were supervised by the study staff. Since the participants were only “moderately” resistance trained, meaning they performed at least one resistance-training workout per week over the past 6 months (and were familiar with the squat and bench press), the results may not be generalizable to athletes and other well-trained populations.

Every month we summarize over 150 of the most noteworthy health and nutrition studies. Other health categories related to this summary include:Try Examine+ for free to view the latest research in 25 health categories and the entire Study Summaries archive, access our Supplement Guides, and unlock the Examine Database. Plus, earn continuing education credits!

Get free weekly updates on what’s new at Examine.

This Study Summary was published on March 2, 2022.