Advertisement - Continue Reading Below hip flexors bring the leg forward easily and powerfully while you run, so if those muscles are tight or weak, you won’t run as efficiently. Instead, you may feel pain in your hips during or after your workout, and tight or weak hip flexors can start a chain reaction of poor mechanics throughout your body that end up manifesting themselves as injuries.

Fortunately, there’s a quick test Half Marathon Training Thomas Test, this simple and effective diagnose weak or tight hips. Because there are five muscles in the hip flexor group—the psoas major, iliacus, rectus femoris, sartorius, and pectineus—the results of the Thomas Test can help determine which specific muscle needs to be strengthened or stretched to support the hip joints in your quest to run pain-free.

How to Do the Thomas Test

Lie face up on the edge of a bed or table so your legs hang off at 90-degree angles. From there, bring both knees toward your chest—keep your back still and flat—then slowly straighten one leg and let it hang off the edge.

thomas test
Trevor Raab
A passed Thomas Test, where the back and thigh are flat against the table and the knee hangs off at a 90-degree angle.

If your back and the back thigh of the lowered leg stay flat against the surface while your hanging knee is perpendicular, congratulations! You passed! Happy Hips!

However, if

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  • your lowered knee is bent, but the back of your thigh rises off the surface, or
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then you need to add hip flexor exercises to your workout routine. Each of those symptoms connects to a specific muscle of the hip flexor group, and so being detailed about the results RW+ Membership Benefits.

Hip Flexor Stretches and Strength Moves

DAA Industry Opt Outtrengtheners Nutrition - Weight Loss hip flexor stretches that Nutrition - Weight Loss Achy Hips? It’s Time to Focus on the Iliacus. Kristopher Ferrera, to determine if your hips are weak or tight. Called the, previously told Runner’s World that even something as easy as rolling out the area with a lacrosse ball will work wonders for hip tightness.

Hip imbalances frequently begin when people, including runners, How to Master the 5k sitting at a desk or in front of a screen. This causes the flexor muscles, which help to bring the knee up toward the torso, to shorten. That’s why, Tom Holland, an exercise physiologist and CEO and founder of TeamHolland LLC, told Runner’s World that “never before has strength-training, stretching, and mobility work been more important for runners.”

Whether it’s a simple new stretch to add to your regular routine or a unique element to add to your workout, our guides have everything you need to alleviate hip tightness and become a more efficient runner.

What to Know if You’re a Quad-Dominant Runner

Get the Hip Flexor Stretches


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Matt Rudisill is an Associate Service Editor with the Hearst Enthusiast Group. A Nittany Lion through-and-through, Matt graduated from PSU in 2022 with a degree in journalism and worked in communications for the university's athletic department for the past three years as the main contact and photographer for its nationally-ranked cross country and track & field teams. Matt was also heavily involved in communications efforts for the Penn State football team’s 2024 College Football Playoff run as well as the Nittany Lion men’s basketball team’s 2023 NCAA Tournament appearance. In his role with Hearst’s Enthusiast Group, Matt contributes to both Runner’s World and Bicycling magazines, creating service content to benefit runners and cyclists of all ages. When he’s not out jogging, Matt can be found tweeting bad takes about the Phillies or watching movies.