According to conventional fitness wisdom, you should train each muscle group three times a week to maximize muscle growth. Many bodybuilders follow this plan. At the other end of the spectrum are those who believe training each muscle group weekly is enough when you’re training with heavy resistance and a sufficient volume to fatigue the muscles enough to grow. How does training frequency impact muscle growth? Is more frequent training better when it comes to building lean body mass?
Muscle Hypertrophy and Training Frequency: Does Training More Often Affect Muscle Growth?
A review published on the Strength and Conditioning Research reviewed three studies comparing muscle growth to training frequency. Although a number of studies have looked at this issue, some didn’t adequately control for differences in training volume. When a person works out three times a week, their total volume is often higher than someone who trains only once a week. This review looked only at studies that controlled for total training volume.
Of the three studies analyzed, one compared training once per week with 3 times weekly training among trained lifters. One group did 3 sets total of each exercise using a resistance of 80% of one-rep max at a training frequency of 3 times weekly. A second group did the same number of sets at 80% of one-rep max but only trained once a week. At the end of a 12-week period, the group that trained 3 times a week showed slightly greater increases in lean body mass relative to the group who trained once weekly.
Another study of trained subjects looked at the effects of strength training 3 times weekly versus training twice a day three days a week. In this study, training twice a day lead to a greater increase in quadricep volume than training only once. Yet another study compared training 4 times weekly with training 4 times weekly twice a day. This one was only 3 weeks in length and involved 10 nationally ranked bodybuilders. This particular study was criticized for being too short in duration (only 3 weeks) and using too small a sample size. Nevertheless, it showed twice a day training lead to smaller increases in muscle size than training once a day.
What conclusions can you draw from these studies? The frequency of training doesn’t have a huge impact on muscle growth in trained individuals, although, excluding the short-duration study, the trend was towards greater muscle growth with higher frequency training.
What about untrained individuals? Studies look at training frequency in untrained people showed higher training frequencies — including 2 versus 4 times weekly, 3 versus 4 times, or 2 versus 3 times — had no significant impact on muscle growth.
What Conclusions Can You Draw?
If you’re untrained, resistance training more often than 2 or 3 times a week probably won’t enhance muscle development. In fact, you run the risk of not giving your muscles adequate recovery time. For trained individuals, increasing the frequency of training may boost muscle growth slightly, although it’s hard to say due to the limited number of studies. Based on the current research, higher training frequencies appear to offer limited additional benefits, especially for untrained individuals.
What Training Frequency Should You Use?
Resistance training once a week sounds like an expedient way to build muscle. The problem with hitting a single muscle group only once a week is you have to do a relatively high volume and intensity to get the muscle to grow. You may end up feeling zapped of energy and, possibly, sore a day or two after a workout due to the intensity and volume of the workout. Plus, there seems to be a limit to the amount of stimulation a muscle can respond to during a single session. One high-intensity, high-volume session a week may exceed this limit.
If you train only once weekly, you have to stimulate the muscle group you’re targeting with enough intensity and volume to force it to grow. Your muscles usually recover from a resistance training workout within a 48- to 72-hour period. Once they’ve recovered, you should ideally hit them with resistance soon after recovery to maximize growth. Weekly training doesn’t allow you to do this.
When you train three times a week, you don’t have to use as much volume because you know you’ll be working the muscle again in 48 hours. Once-a-week training does have some benefit. It’s useful if you’re trying to maintain your current strength level and muscle size and aren’t trying to get the muscle to grow. One study found that 50 trained men and women who reduced their training frequency to 1 or 2 days a week were able to maintain their strength gains. It’s also an approach you can use if you have limited workout time.
If your goal is to improve strength and increase muscle size, training each muscle group 2 to 3 times a week with 48 hours of recovery time between each session is a good prescription. Once-a-week training isn’t optimal for muscle growth due to the intensity and volume needed, but training 4 or 5 times a week or training twice a day isn’t better and may be detrimental because it doesn’t give your body enough time to recover. Olympic caliber lifters train more than once a day and train more days of the week, but they’ve achieved a very high fitness level and their primary focus is on training — it’s their job. Most people don’t have the time or the high fitness level it takes to do this.
The Bottom Line?
Whether you do split training and work upper body one day and lower body another or work your entire body during a single session, training each muscle group 2 times a week provides a good balance of muscle stimulation and recovery time. Always give the muscle group you worked at least 48 hours to recover and repair before working it again. Training once a week with sufficient volume and intensity should make you stronger but it may not be enough to optimize muscle growth.
Once you’ve reached a high level of fitness, experiment with adding an additional day of training for variety, but keep in mind your muscles are perfectly capable of growing when you train each muscle group only 2 or 3 times a week. How often you train also depends on how quickly you recover between workouts. If you’re experiencing fatigue and your performance is suffering, you may be training too frequently. Take these factors into consideration when planning your training.
References:
Strength and Conditioning Research. “How does training frequency affect hypertrophy?” (January 2013)
Int J Sports Med. 1988 Oct;9(5):316-9.
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