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Strengthen these muscles to avoid leg fatigue

Research says your plantar flexors are the first leg muscles to give up on a run — here's what to do about it

Leg fatigue is one of the many reasons you get tired during a hard run and have to slow down. A group of researchers in the U.K. decided to investigate which leg muscles typically fatigue first, and found that the plantarflexion muscles, which include the muscles in your calves, your ankles and the bottom of your feet, tire faster than the other muscles of the leg. For this reason, runners should spend some time strengthening these areas to avoid injuries and run longer and faster.

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What are the plantar flexors?

There are several muscles that make up your plantar flexors, including (but not limited to) your gastrocnemius (which is the largest muscle in the group and makes up half of your calf), the soleus (which connects the Achilles tendon to your heel) and your plantaris, a long, thin muscle that runs along the back of the leg, which helps flex your ankle and knee. There are also several other deep muscles that connect to your ankles and toes to help flex your toes and feet.

The study

The study, published by the American College of Sports Medicine, assessed 18 male and female middle-distance runners while running hard on the treadmill for three minutes. It found that by the end of the test, the runners’ plantar flexors were contributing less than the other muscles in the leg, forcing the knees to work harder. The researchers concluded that improving the fatigue resistance of the plantar flexors may be beneficial for middle-distance runners.

While this study did not focus specifically on long-distance runners, the findings still apply to people tackling longer runs and races. Strengthing the plantar flexors to increase their fatigue resistance will have a protective effect for your knees, thereby reducing your risk for injuries. Additionally, having stronger legs will help make you more powerful so you can run faster.

RELATED: Runner’s PSA: your foot pain might not be plantar fasciitis

Exercises to strengthen your plantar flexors

Toe taps: Stand with your feet hip-width apart, with your hands on your hips, and put one leg out in front of you, keeping your foot on the ground. Tap with your forward foot, keeping your heel on the ground and raising your toes high in the air, then pressing them firmly into the ground. Do this for one to two minutes on each foot.

Ankle rotations: Sit in a chair and use your hands to hold one of your legs slightly off the ground. Rotate your ankle clockwise for about 20-30 seconds, the counter-clockwise for another 20-30 seconds before switching to the other leg. The rotations should be slow and deliberate, and you should be able to feel the stretch on the front of your leg.

Single-leg calf raises: Stand on one leg with the other lifted slightly off the ground. Slowly raise your heel off the ground until you’re standing on your toes, then slowly lower back down. You can use a wall or railing for balance if you need it. Repeat this for 10-15 repetitions on each leg.

Banded foot pulls: Wrap one end of a resistance band around a sturdy object, like the leg of a heavy table. Loop the other around the top of your foot. Sit on the floor with your legs out in front of you, and slide backward until there is no slack in the band. Try to pull the band toward your body using only your foot, hold for a couple of seconds, then slowly return to the starting position. Repeat 10-15 times, on both legs.

Towel crunches: Sit or stand with a towel on the ground at your feet. Keep your heel on the ground and grab the towel with just your toes, pulling it toward your body. Continue doing this until you’ve pulled the entire towel to your foot and repeat on the other foot.

Jump rope: Use a skipping rope to jump for about 1-2 minutes to build strength in your feet and lower legs. Incorporate this into your training two to three times per week.