Clamshell Exercise: How to Do It, Muscles Worked and Variations
How to do the clamshell exercise properly to build glute strength and hip stability. Muscles worked, common mistakes, band variations and a simple sets and reps plan.
By Mike Shilling, Recovery & Training Editor · Updated 26 July 2026
Tight hamstrings are one of the most common complaints from anyone who sits at a desk, runs, or lifts, and the fix is more about consistency than intensity. The hamstrings run down the back of your thigh from your sitting bones to below the knee, and when they're stiff you feel it everywhere: a nagging pull when you bend to tie your shoes, a locked feeling at the bottom of a squat, tension that creeps into your lower back. Good news is that hamstrings respond well to regular, sensible stretching. Here are seven of the best hamstring stretches, how long to hold them, and how to build them into a routine that actually loosens you up over a few weeks rather than one heroic session that leaves you sore.
Before the moves, a few rules that make the difference between progress and a pulled muscle.
Warm up first. Cold hamstrings don't stretch well and are easier to strain, so do these after a walk, a workout, or five minutes of easy movement. Ease into the pull until you feel a strong stretch without any sharp or nervy pain, then stop pushing and just breathe. Hold each stretch for around 30 seconds; that duration has been shown to beat very brief holds for improving flexibility (static stretch vs dynamic range of motion study). Never bounce. Small bouncing movements trigger a reflex that tightens the muscle, which is the opposite of what you want. Breathe out as you settle deeper, and treat a stretch that suddenly sharpens as a signal to back off.
The single best habit for tight hamstrings
Little and often beats one long, painful session. Two or three 30-second holds per stretch, three to five days a week, will loosen your hamstrings far more reliably over a month than an occasional brutal stretch that leaves you aching. Flexibility is built by frequency.
Lie on your back with one leg bent, foot flat, and the other leg raised toward the ceiling. Loop a resistance band, yoga strap or a towel around the ball of the raised foot and gently draw the leg toward you, keeping a soft bend if you need it. This is the safest deep hamstring stretch because the floor supports your back and spine, so you can relax into it without rounding.
It's the one I'd start most people on, especially anyone with a grumpy lower back. A resistance band or a long yoga strap gives you far more control than reaching for your toes. Hold for 30 seconds each side, keeping the raised leg as straight as your flexibility comfortably allows.
Stand with your feet hip-width apart, then hinge at the hips and fold forward, letting your head and arms hang toward the floor. Keep a micro-bend in the knees rather than locking them, and let gravity do the work instead of yanking yourself down. You should feel a broad stretch through both hamstrings and often into the lower back.
The forward fold is convenient because you can do it anywhere, no kit required. If your hamstrings are very tight, rest your hands on a chair seat or your shins rather than forcing them to the floor. Let your upper body get heavier with each exhale for 30 seconds.
Sit on the floor with both legs straight out in front of you, feet flexed, and hinge forward from the hips reaching toward your feet. The aim isn't to touch your toes at any cost; it's to keep your back reasonably long as you fold, so the stretch stays in the hamstrings rather than collapsing into your spine. A folded exercise mat or a cushion under your sitting bones tilts your pelvis forward and makes this far more effective if you're stiff.
Stop where you feel a firm pull and hold. Rounding hard to grab your feet feels productive but mostly stretches your back, so resist the urge and keep the hinge honest.
On your back, keep one leg flat on the floor and slowly lift the other straight up as far as it will go without bending, then hold it there with your hands behind the thigh. It's similar to the strap stretch but relies on your own grip, which some people prefer for the extra control near the top of the range.
Keep the down leg pressed into the floor. If it creeps up or your hips rock, you've gone too far, so lower the raised leg slightly until everything settles. Thirty seconds each side.
Place one heel on a low step, bench or the bottom stair, keeping that leg straight, and hinge forward from the hips over the raised leg. The higher the surface, the stronger the stretch, so start low. A sturdy plyo box or a solid chair works well as the platform.
This one lets you target each hamstring individually and is easy to adjust: point your toes up for more pull, or ease the hinge if it's too much. Keep your back flat as you fold forward, not rounded, and hold for 30 seconds a side.
Lie on your back with your bottom close to a wall or a door frame and rest one leg straight up against it, the other extended along the floor. Your own leg weight and the wall create a gentle, low-effort stretch you can hold comfortably for longer than the more active versions. It's the recovery-day option: relaxing, sustainable, and kind to a tired lower back.
Shuffle your hips closer to the wall for more stretch, further away for less. Because it asks so little of you, this is a good one to hold for a full minute or two while you unwind.
Not every hamstring move should be a long hold. Before a run or a leg session, stand tall holding something for balance and swing one leg forward and back in a controlled arc, gradually increasing the range. Keep the swings smooth, not violent. This is a dynamic stretch, and it's the right tool before exercise because it warms and mobilises the muscle without the brief power dip that long static holds can cause beforehand.
Do 10 to 15 swings per leg. Save the static stretches above for afterward, when you're warm.
You don't need all seven every time. A dependable weekly approach looks like this:
Give it three to four weeks of consistency before judging progress. A systematic review of stretching found both static and dynamic stretching reliably improve hamstring flexibility over time, so the method matters less than showing up (stretching and hamstring flexibility meta-analysis). It's also worth pairing stretching with some strengthening, because strong hamstrings through a full range tend to feel less tight than weak ones. The NHS suggests including flexibility and strength work as part of a rounded week of physical activity, and hamstring health sits right in that overlap.
If tightness is really about weakness, adding a few sets of the moves in our hamstring exercises guide alongside these stretches will do more than stretching alone. And if you're stiff from squatting, our glute stretches make a natural companion routine.
Hold each stretch in a position where you feel a strong pull but no sharp pain, breathe slowly, and stay there for around 30 seconds. A supine stretch with a strap, a standing forward fold and a seated forward fold cover most of the muscle. Do them after activity or when you are warm, three to five times a week, and give it a few weeks to show. Static holds of about 30 seconds have been shown to improve hamstring range of motion more than very short holds.
Around 30 seconds per stretch is the sweet spot for most people. Research comparing stretch durations found a 30-second hold produced meaningful gains in hamstring flexibility, with little extra benefit from going much longer in a single hold. Repeat each stretch two or three times rather than holding one rep for minutes.
Usually it is a mix of sitting for long stretches, not moving through a full range often, and training the muscle hard without stretching it. Tightness can also be your nervous system protecting a weak or overworked muscle. Sometimes what feels like a tight hamstring is actually referred tension from the lower back or nerves, which is why gentle, regular stretching plus some strengthening works better than aggressively forcing the stretch.
Daily gentle stretching is fine and can speed up progress, as long as you never bounce into pain. If your hamstrings feel sore from training, ease off the intensity rather than skipping movement entirely. Most people see good results stretching three to five times a week, so daily is a bonus, not a must.
Save long static holds for after exercise or a separate mobility session, when the muscle is warm. Before a workout, use dynamic moves like leg swings and walking kicks instead, because holding a long static stretch cold can briefly dull power. A warm muscle stretches further and more safely.
They can contribute. Tight hamstrings pull on the pelvis and can tip it in a way that adds strain to the lower back, especially when you bend or lift. Loosening the hamstrings often takes some pressure off the lower back, but persistent back pain is worth getting checked rather than self-treating with stretches alone.
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