Runners: Is One Side of Your Body Weaker Than the Other?

Lauren Bedosky
by Lauren Bedosky
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Runners: Is One Side of Your Body Weaker Than the Other?

If you’re a runner, hopefully you’re already wise to the advantages of doing regular strength workouts. But, while strength training is key for doing well in any activity, there’s a type that’s especially critical for runners: unilateral strength training.

According to Lauren Loberg, DPT, board-certified clinical orthopedic specialist with TRIA Orthopaedic, the top benefit of performing unilateral strength exercises — like single-leg squats and deadlifts — is you’re training your body to meet the demands of your sport. After all, running is a single-leg activity, so it only makes sense that you would benefit from moves that shore up your single-leg strength, stability and coordination.


More important, unilateral strength exercises help balance your dominant and non-dominant side.

Everyone has a dominant side that’s typically stronger than their non-dominant side. The thing is, when one side — in the case of running, one leg — can’t pull its own weight, the stronger side has to kick in to compensate. Over time, the added impact and stress can wreak havoc on your joints, muscles, tendons and ligaments, leading to general pain and overuse injuries.

For example, a study published in Clinical Journal of Sport Medicine reveals that, in runners with a single-leg overuse injury, there were significant differences in strength between the hip muscles on the injured and non-injured side. The researchers can’t say for sure that injury was caused by muscle imbalance or if the muscle imbalance was caused by the injury. However, they suggest there’s an association between muscle imbalance and overuse injury.


If you’re not sure how your single-leg strength stacks up, don’t wait until pain and injuries surface to find out. Instead, perform the following tests and then incorporate a few recommended strength exercises to shore up weaknesses.

Loberg prescribes three tests to help runners gauge their single-leg strength, flexibility and stability. “These tests can be an eye-opener as to how ‘off’ a side is,” she says.

Aim for a score of good to great for each test. If you come up short, incorporate Loberg’s recommended moves into your strength routine and retest after 4–6 weeks.

You may find it helpful to download a free metronome app (try this one) for the step-up and single-leg glute bridge tests. If you don’t have access to a metronome or metronome app, simply try to maintain a steady pace during both tests. You’ll also need a measuring tape for the squat with lateral leg reach test.


Measures: Single-leg strength

How to do it: Use a metronome set at 40 bpm. A beat marks the step up and a beat marks returning to floor. Plant your right foot on a box, bench or chair that’s at least 18 inches high. Lean forward slightly, and press through your planted heel to lift your body until your right leg is straight. Return to starting position by lowering your left foot back down to the floor with control. Continue on one leg until you’re unable to complete any more reps with good form at pace. Switch sides and repeat with the opposite leg. Record your score for each leg. Add weight to increase difficulty.


Measures: Balance, flexibility and stability

How to do it: Stand with feet hip-width apart and place one end of a measuring tape under your left foot. Shift your weight onto your left leg, push your butt back and bend at the knees to lower into a squat. Once you’re in the bottom position, reach your right foot out to the side as far as you can while maintaining your balance. Pull the measuring tape along the floor to note how far you were able to reach. Then, repeat the movement, this time reaching out with the opposite leg.


Measures: Unilateral glute and core strength

How to do it: Set metronome to 60 beats per min, where one beat marks the top of the bridge and one beat marks when you touch back down. Begin lying on your back with knees bent and feet hip-distance apart on the floor. Straighten your right leg and lift your heel off the ground. To initiate the movement, push into the floor with your planted foot, squeeze your glutes and raise your hips off the floor. Keep your right leg raised and push your hips as high as you can without arching your lower back. Continue on one leg until you’re unable to complete any more reps with good form at pace. Switch sides and repeat with the opposite leg. Hold a weight on the front of your hips to increase difficulty.


If your test scores were less than ideal, add the following single-leg exercises to your strength routine 2–3 times per week. Then, retest after 4–6 weeks. For each move, start with three sets of 10 reps on each leg and build up to 2–3 sets of 30 reps per leg.


Stand tall with feet hip-width apart. Keeping your weight on your right leg, step the left foot back and around your right leg until you end in a lunge. Drive back to starting position by pushing through your right hip, then kick your left leg to the side as high as you can without straining. Complete all reps on one side before switching.


Stand tall. Shift your weight onto your right leg, lift your left foot off the ground and hold for three seconds. Then, squat down halfway and jump explosively onto your left foot, aiming to cover as much distance as possible. Land softly on your left foot and hold for three seconds before jumping explosively back onto your right foot. Continue alternating sides for reps.


Stand tall with feet hip-width apart. Lift one foot off the floor, lower slightly into a squat position to load your standing leg, and explode upward to jump as high as you can. Land softly on one foot and immediately launch into the next rep. Complete all reps on one side before switching.

About the Author

Lauren Bedosky
Lauren Bedosky

Lauren is a freelance fitness writer who specializes in covering running and strength training topics. She writes for a variety of national publications, including Men’s HealthRunner’s WorldSHAPE and Women’s Running. She lives in Brooklyn Park, Minnesota, with her husband and their three dogs.


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