Legs, core, maybe calves — strength training tends to focus on the same muscles. One is frequently left out: the hip flexor. Yet it’s the muscle that pulls your thigh forward with every stride, largely determining how long your step is and how efficiently you run.
This creates a blind spot: a muscle group that rarely gets attention, despite being among the most important for stride length, running economy, and injury prevention. In this post you’ll find out what’s behind the term, why these muscles are often both weak and tight at the same time, and which four exercises will strengthen them effectively — each described in enough detail to follow along straight away.
What exactly is the hip flexor?
“Hip flexor” doesn’t refer to a single muscle but to a group of muscles at the front of the hip that share one job: pulling the thigh upward and forward toward the abdomen — in running terms, the swing phase when you lift your knee.
By far the strongest and most important of these is the iliopsoas. It consists of two parts — the psoas major and the iliacus — which merge into a shared tendon and attach to the femur. Anatomically, the psoas is unusual: it originates directly at the lumbar spine, making it one of the few muscles that connect the trunk directly to the leg. Through this connection it influences not only leg movement but also the stability of the pelvis and lower back. Alongside the iliopsoas, smaller muscles such as the rectus femoris, sartorius, and pectineus also contribute to hip flexion.
Why the hip flexor matters so much for runners
At an easy jogging pace, the hip flexor barely registers. That changes the faster you go. Speed comes from two sources: longer strides or more strides per minute. At slow to moderate paces, a longer stride is what counts most — and that comes from a powerful push-off, primarily from the calves. But stride length has a ceiling. At higher speeds, the body shifts to increasing stride frequency: legs need to swing forward faster — and that’s exactly what the hip flexor is for. A biomechanical study by Dorn et al. (2012) showed that the iliopsoas does progressively more work as pace increases. At sprint speed it is among the most heavily loaded muscles in the entire leg.
This translates into two key benefits of a strong hip flexor:
Greater stride length and better running economy. Your pace is the product of stride length and stride frequency. The hip flexor makes a significant contribution to stride length — and stride length is closely linked to running economy, meaning how much energy a given pace costs you. The more efficient you run, the longer you last. A study with recreational runners found indications that strong, well-balanced hip musculature is associated with better running economy.
Protection against injury. When the hip musculature is weak, the body compensates. If the hip can’t stabilise the pelvis, other structures take over — and that can have knock-on effects at the knee and lower back. Research points to a connection with common running complaints such as iliotibial band syndrome (pain on the outside of the knee). The focus there is primarily on the lateral gluteal and hip muscles, and the relationship is considered indicative rather than proven as a sole cause. What is clear: a strong, well-coordinated hip produces a more stable pelvis and cleaner running mechanics.
The paradox: weak and tight at the same time
This is a point that confuses many runners. The hip flexor often feels tight and tense — the instinctive response is to stretch it. But that tightness frequently has its roots in weakness rather than overuse.
The reason lies in our daily lives. Anyone who spends many hours sitting — and most of us do — keeps the iliopsoas in a shortened position for extended periods. Over time the muscle can become accustomed to this position while rarely being challenged to work hard. Sitting also weakens the antagonists: the glutes and hamstrings. The result is a muscle that can neither reach its full length nor produce its full force.
The practical takeaway: stretching alone won’t fix the problem. A sustainable approach combines mobility work with targeted strengthening — and that’s exactly what the following exercises address.
4 effective hip flexor exercises
For most of these exercises you need only a mini band — a small, closed-loop resistance band that you place around your feet or ankles — and some floor space. Start with no or light resistance and progress once the movement pattern is solid. With all exercises: keep your core actively engaged and avoid arching the lower back.
1. Lying psoas march
The foundational exercise for isolating and activating the psoas. Lie on your back and bend both legs so that your knees are at a 90-degree angle directly above your hips (a mini band around the midfoot increases resistance). Gently press your lower back into the floor and brace your core. Slowly and with control, extend one leg forward while the other knee stays firmly in place. Return it under control and switch sides. 2–3 sets of 10–12 repetitions per leg.
Key point: The lower back stays in contact with the floor throughout the entire movement. If it lifts, the resistance is too high.
2. Standing psoas march with band
This variation is more running-specific because it replicates the upright posture and arm-leg coordination of actual running. Place the mini band around both feet and stand tall. Drive one knee powerfully upward and forward to roughly hip height while swinging the opposite arm forward as you would when running. Hold briefly, then lower the leg slowly over about three seconds — this controlled lowering phase builds eccentric strength. 3 sets of 10–12 repetitions per leg.
Key point: Stay upright. If you’re leaning forward, the band is too strong. Beginners may hold a wall for support with one hand.
3. Dead bug
Primarily a core stability and pelvic control exercise — the very foundation that effective hip flexor training depends on. The hip flexor works hard throughout, especially in controlling the descending leg. Lie on your back, arms pointing straight up and legs in the 90-degree position. Simultaneously lower your right arm behind your head and extend your left leg toward the floor, keeping the lower back pressed down. Return to centre, then switch sides. 2–3 sets of 8–10 repetitions per side.
Key point: The movement is slow and deliberate. You should just be able to slide a finger between your lower back and the floor — maintain that tension throughout.
4. Mountain climber with sliders
A dynamic exercise combining strength, core stability, and a cardiovascular element. You need two sliders — towels on a smooth floor work just as well. Get into a plank position, shoulders over wrists, body in a straight line. Draw one knee in toward your chest with control and slide the foot back out, keeping the hips from rising. Alternate sides or work one side at a time. 2–3 sets of 20–30 seconds.
Key point: Hips stay low, core stays active. To make it harder, increase the tempo.
How to fit this training into your week
You don’t need to do all four exercises at once. Pick two or three and perform them twice a week — ideally on easy run days or after your regular strength session. Start with the isolated variations (lying and standing psoas march, dead bug) until you have a confident feel for the movement and a stable pelvic position. Only then move on to the more dynamic option (mountain climber).
The standing psoas march also makes an excellent activation drill before a run — it wakes up the hip flexors and immediately improves knee drive and pelvic stability.
One final note: if you’re already experiencing pain in the hip flexor area — for example during faster running or a noticeable snapping sensation at the hip — reduce your running volume first and give the muscle time to recover before starting any intensive strength work. For persistent complaints, seeing a specialist is worthwhile.
A strong, well-functioning hip flexor isn’t a glamorous training goal — but that’s precisely what makes it so valuable. It’s working with every single stride. A few minutes of targeted work each week pays off in longer strides, better running economy, and a lower risk of injury.
This post is also available in DE.