Why use an exercise ball instead of kneeling?

The ball carries part of your body weight and keeps the rear knee off the floor, so it suits anyone who finds kneeling uncomfortable. It also lets you control the depth by how much weight you settle onto the ball. If balancing is a problem, the Kneeling Hip Flexor Stretch gives a steadier base.

How long should I hold the stretch?

Hold each side for 20 to 30 seconds and repeat until you have spent about a minute in the stretch on each side. Doing this at least two or three days a week is enough to build hip extension over time.

Can I do this stretch before a workout?

Yes, with short holds. A review of hip flexor stretching studies in healthy people found that stretching the hip flexors for 30 to 90 seconds did not impair strength, sprint or jump results, while very long bouts of 4.5 to 8 minutes caused a small drop. Keep pre-workout holds short and follow them with your usual dynamic warm-up.

Will stretching my hip flexors fix my posture or the way I run?

Not on its own. In a three-week study of healthy adults with limited hip extension, a home hip flexor stretching program increased passive hip extension but did not change pelvic tilt, lower-back extension or hip extension while running. Treat it as a way to gain range of motion rather than a fix for how you move.

Where should I feel this stretch?

At the front of the rear hip and the top of the rear thigh. Feeling it in the lower back means the pelvis has tipped forward, and a pinch deep in the front of the hip means you have sunk too far, so tuck the tailbone and come up slightly.

What size exercise ball do I need?

Pick a ball that lets you sit with your hips level with or slightly above your knees and your feet flat on the floor. For most adults that means a 55 cm ball at about 5 ft 1 in to 5 ft 7 in tall and a 65 cm ball at about 5 ft 8 in to 6 ft 2 in.

Exercise Ball Hip Flexor Stretch

What Is the Exercise Ball Hip Flexor Stretch?

Exercise Ball Hip Flexor Stretch is an isolation exercise that primarily targets the hip flexors of the rear leg, lengthening the iliopsoas, rectus femoris, tensor fasciae latae and sartorius at the front of the hip. It is a beginner-level static stretch done sitting astride a stability ball in a split stance, with the front knee bent and the rear leg reaching back so the rear hip moves into extension.

The ball carries part of your body weight and keeps the rear knee off the floor, so you can hold a tall lunge position without kneeling and without supporting your full weight on the legs. How far you sink is set by how much weight you let settle onto the ball, which makes the stretch easy to dose. That suits anyone who finds kneeling uncomfortable on the knee, as well as people who want a gentle hip flexor stretch they can hold with an upright torso.

The stretch is most useful for people who spend long hours sitting, and for runners, cyclists and lifters who want more hip extension for striding, lunging and standing tall at the top of a hip hinge. Because the rear knee stays only slightly bent, the work falls mainly on the single-joint hip flexors. Bending the rear knee further shifts more of the stretch into the rectus femoris, which is what the Couch Stretch is built around.

Pelvic position matters more than depth here. A gentle tuck of the tailbone and a squeeze of the rear glute keep the stretch at the front of the hip, while sinking deep with the pelvis tipped forward mostly bends the lower back. Fit it into a cool-down or a mobility session, or use short holds in a warm-up. If balancing on the ball feels shaky, build the position first with the Standing Hip Flexor Stretch or the Kneeling Hip Flexor Stretch.

Muscles Worked

MuscleActivation

Sartorius: Primary
Tensor Fasciae Latae: Primary
Rectus Femoris: High
Adductor Longus: Medium
Gluteus Maximus: Low
Rectus Abdominis: Low
External Oblique: Minimal
Vastus Lateralis: Minimal

Instructions

Choose a ball that lets you sit with your hips level with or slightly above your knees, and set it on a non-slip floor.
Sit on the center of the ball, then step one foot forward and plant it flat, with the knee bent about 90 degrees over the ankle.
Reach the other leg straight back and rest on the ball of that foot, heel lifted and knee slightly bent, so the ball sits under your hips and front thigh.
Rest your hands on the ball beside your hips and sit tall, ribs stacked over the pelvis and eyes forward.
Gently tuck your tailbone under and squeeze the glute of the rear leg.
Let your hips sink slowly down and forward over the ball, sliding the rear foot back a little, until you feel a stretch at the front of the rear hip and thigh.
Hold for 20 to 30 seconds, breathing slowly, with the torso upright and the lower back not arching.
Rise back up, step the rear foot in, and repeat on the other side.

Common Mistakes

Arching the lower back
Letting the pelvis tip forward as you sink moves the stretch out of the hip flexors and into the lumbar spine.
Skipping the pelvic tuck
Without tucking the tailbone and squeezing the rear glute, most people feel little at the front of the hip and lean further to chase the stretch.
Sinking too deep
Dropping the hips as far as they will go tends to pinch the front of the hip, when a few inches with the pelvis tucked is usually enough.
Leaning the chest forward
Folding the torso toward the front thigh lets the rear hip flex again and takes tension off the muscles you are trying to stretch.
Letting the front knee drift
A front knee that caves inward or a foot that slides makes the ball shift and leaves you fighting for balance instead of relaxing into the stretch.
Bouncing on the ball
Bouncing in and out of the end position makes the ball roll and gives the hip flexors no time to relax.

Injuries

Exercise Ball Hip Flexor Stretch is a low risk exercise when performed with proper technique. The two things that go wrong are the ball shifting under you and the stretch turning into a lower-back arch. If the pelvis tips forward as you sink, the lumbar spine takes the extension instead of the hip, which shows up as pressure in the lower back, and sinking too far can produce a pinch deep in the front of the hip joint.

Use an anti-burst ball sized so you can sit with your hips level with or slightly above your knees, inflated to its marked size and placed on a non-slip floor or mat. Keep both hands on the ball and the front foot flat throughout. Tuck the tailbone under and squeeze the rear glute before you sink, then lower only a few inches and hold rather than bouncing.

If staying balanced on the ball is the limiting factor, the Standing Hip Flexor Stretch and the Kneeling Hip Flexor Stretch give a steadier base. To go further, the Low Lunge takes the hip deeper and the Couch Stretch adds knee bend to load the rectus femoris.

Stop if you feel sharp pain, pinching at the front of the hip, pain in the lower back, or numbness or tingling down the leg. Anyone recovering from hip surgery or a hip or groin injury should get clearance before stretching into hip extension.

Overview

Primary Focus: Hips & groin
Equipment: Exercise ball
Modality: Stretching
Difficulty: Beginner

Alternative Exercises

Frequently Asked Questions

Q: Why use an exercise ball instead of kneeling?: The ball carries part of your body weight and keeps the rear knee off the floor, so it suits anyone who finds kneeling uncomfortable. It also lets you control the depth by how much weight you settle onto the ball. If balancing is a problem, the Kneeling Hip Flexor Stretch gives a steadier base.
Q: How long should I hold the stretch?: Hold each side for 20 to 30 seconds and repeat until you have spent about a minute in the stretch on each side. Doing this at least two or three days a week is enough to build hip extension over time.
Q: Can I do this stretch before a workout?: Yes, with short holds. A review of hip flexor stretching studies in healthy people found that stretching the hip flexors for 30 to 90 seconds did not impair strength, sprint or jump results, while very long bouts of 4.5 to 8 minutes caused a small drop. Keep pre-workout holds short and follow them with your usual dynamic warm-up.
Q: Will stretching my hip flexors fix my posture or the way I run?: Not on its own. In a three-week study of healthy adults with limited hip extension, a home hip flexor stretching program increased passive hip extension but did not change pelvic tilt, lower-back extension or hip extension while running. Treat it as a way to gain range of motion rather than a fix for how you move.
Q: Where should I feel this stretch?: At the front of the rear hip and the top of the rear thigh. Feeling it in the lower back means the pelvis has tipped forward, and a pinch deep in the front of the hip means you have sunk too far, so tuck the tailbone and come up slightly.
Q: What size exercise ball do I need?: Pick a ball that lets you sit with your hips level with or slightly above your knees and your feet flat on the floor. For most adults that means a 55 cm ball at about 5 ft 1 in to 5 ft 7 in tall and a 65 cm ball at about 5 ft 8 in to 6 ft 2 in.