Muscle Evolved

Does Running Make You Lose Muscle? – What You Need to Know

By Zac Hyde · · Updated

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When you are trying to gain muscle mass, you will become more conscious about the type of exercises you perform, as well as your dietary choices.

One common question that beginners ask is whether running exercises negatively impact muscle mass.

In this article, we will cover the effects of running on your lean muscle mass, as well as how you can use running exercises to support your leg muscles.

The effects of running on your lean muscle mass

The impact of running exercises on your lean muscle mass depends on their frequency, intensity, and duration.

Contrary to popular belief, running may help build some lower body muscle in people who are new to training. In one study, researchers recruited 12 recreationally active college students to do 4 hard 4-minute running intervals (at 90-95% of maximum heart rate), each followed by 3 minutes of active recovery, about 3 days a week.

After 10 weeks, the runners' vastus lateralis (one of the quadriceps muscles) grew by about 11% in cross-sectional area. The small control group showed no gain.

Therefore, and unlike common belief, interval running can increase leg muscle size in untrained people. The study was small, and gains like this are smaller than what dedicated strength training produces.

Some articles claim that running inhibits the enzymes responsible for proteolysis (i.e., protein degradation). That study actually tested cycling intervals done before leg strength training, not running. The combined group grew more, and the authors credited stronger growth signaling rather than less protein breakdown.

Long-distance running is a different stimulus. One study had 30 experienced male amateur runners race 10, 21, or 42 km (6.2, 13, or 26.2 miles). Blood markers of muscle damage rose in every group after the race.

The full-marathon group had significantly higher markers than the shorter-distance groups, and some markers stayed elevated three days later.

In summary, short, hard running intervals can support leg muscle in beginners, while very long runs cause more muscle damage and need more recovery. For most people, moderate running alongside strength training and enough protein does not cause meaningful muscle loss.

Running exercises that build muscles

Since short, high-intensity intervals appear to support leg muscle, you can use them alongside your lower body training.

This is especially useful for people who focus mostly on upper body strength training.

Here are some routine HIIT running exercises to build lower body muscles:

  • 6 sets of 15-second sprints at maximum intensity separated by 2 minutes of light jogging
  • 5 sets of 25-second sprints at maximum intensity separated by 4 minutes of light jogging
  • 4 sets of 45-second sprints at moderate intensity separated by 5 minutes of light jogging
  • 4 sets of 30-second hill sprints, then walk back down the hill and do it again.

Start with 1-2 sessions a week and warm up well before sprinting. Experienced runners can work up to 3 sessions, leaving at least a day of recovery between hard sessions.

Takeaway message

Depending on the intensity and duration of running, it can either support leg muscle or cause more muscle damage that needs recovery. Equipped with this information, do not fear programming a few running sessions per week.

We hope that this article managed to clear out some of the confusion that surrounds this topic. If you found anything vague, feel free to drop your questions in the comment section below.

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