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How many hours of weekly weight training boosts strength? Surprising new study

Is just one hour of weightlifting a week enough to yield results? Interesting new research.

By Steph Green Published May 11, 2025

Muscle man flexing doing cable bicep curl in gym on cable machine — Jean Daniel / Pexels

The Centers for Disease Control estimates only 20% of Americans strength train a few times a week. Some people think you have to spend countless hours pumping iron in pools of sweat to see results. Those of us with busy schedules are focused on getting the most out of the time we spend working out and maximizing our results with the time we have.

In this hot-off-the-press study, researchers explored how many hours of weekly strength training boost muscle strength. Here’s the research.

The study

In a brand new study published in the journal Medicine & Science in Sports & Exercise, 42 healthy resistance-trained adults completed a single set of nine common upper- and lower-body resistance training exercises targeting all major muscle groups in each session. Participants lifted twice weekly for eight weeks and were split into two groups:

The FAIL group trained to failure on all exercises.
The 2-RIR group trained with two repetitions in reserve.

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The workout session was designed to be on the shorter side because people often say that their busy schedules are the reason why they don’t do strength training. The researchers set out to uncover the minimum effective dose where you can still get results in muscle power without spending all of those hours at the gym.

At the beginning and the end of the study, researchers assessed muscle thickness for the biceps brachii and triceps brachii arm muscles as well as the quadriceps femoris, which are the muscles at the front of your thighs. Researchers also measured muscular strength and power endurance.

The results

The results showed that both groups had noticeable gains, with muscle growth being a little more prominent in the FAIL group. There were similar increases in strength and local muscular endurance in both groups. During those two months, the 42 adults gained significant muscle mass and strength even with just two 30-minute sessions a week.

The takeaway

While this is a small study, it shows that single-set routines can certainly be a time-efficient way to promote muscular growth and power, even when transitioning from higher-volume programs. Strength training in shorter durations provides health benefits, builds muscle, and fits into your busy schedule.

Even just one hour a week can yield results, so it’s worth making room in your schedule to prioritize your fitness and wellness and lift those weights. Another study showed that those who did just 30 to 60 minutes of weekly strength training had a 10 to 20% lower risk of complications and fatality from conditions like cancer and heart disease, compared to those who didn’t do any resistance training. I think I might squeeze in a resistance training session later today.

Steph Green is a content writer specializing in healthcare, wellness, and nutrition. With over ten years of experience, she…

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