Hamstring stretch with a strap, a towel or a device: what changes and how to choose

  • Most hamstring stretches fail for a mechanical reason: you cannot hold your own feet with a long spine, so the lower back rounds to make up the distance and the stretch leaves the legs. Every tool here exists to close that gap.
  • The research is clearer about position than about equipment. With the pelvis held tilted forward, flexibility improved; held tucked, it did not, whichever technique was used [3]. Sitting and standing stretches gave equal gains [6].
  • Towel, yoga strap, doorway, leg machine and FlexBuddy® all work if they let you keep the spine long. They differ in how easy that is, how finely they adjust, and whether they hurt your hands.
  • Hold about 30 seconds, two to four times, most days: 30 seconds was as effective as 60, and once a day as effective as three times [9]. Guidelines say about 60 seconds per muscle group on at least two to three days a week [12][13].
  • A device earns its place when it does something a towel does not: holds the posture for you, adjusts in small steps, does not cut into the hands. If you can already sit tall and reach your feet, a towel is enough.

Why you need a tool at all: the reach problem

Your hamstrings are the three muscles on the back of each thigh, running from the sitting bone to just below the knee. To stretch them you have to move the sitting bone away from the knee, which means tipping the pelvis forward over straight legs. The only handle your body offers is your feet, and if your hamstrings are tight your hands stop well short of them. Almost everyone solves this the same way: round the lower back, drop the chest, reach. The pelvis never tips, and the stretch lands in the lumbar spine instead of the thighs. It feels like a stretch. It is the wrong one. A towel or a strap round the sole of the foot lengthens your arms so you can hold the foot while sitting tall. That is the entire reason stretching straps exist.

What a forward bend actually does to your spine

Forward bending is shared between the hips and the lumbar spine, and the share is not equal. In a motion-analysis study of 41 adults, a full forward bend averaged 111 degrees, about 42 from the lumbar spine and 69 from the hips, and in the first 30 degrees the spine moved almost twice as much as the hips [1]. People with a history of low back pain bent even more at the spine early on, and the authors suggested teaching them to use more hip motion, with hamstring stretching as one way to encourage it [1]. That early, spine-heavy part of the bend is the "stretch" most people give their hamstrings every day. Sit-and-reach and toe-touch scores reflect spine and pelvis movement as much as hamstring length [2], so reaching further with a round back proves nothing about your legs; why you cannot touch your toes has the full story.

Pelvic position matters more than the method

The clearest experiment on this predates most stretching straps. Twenty subjects stretched their hamstrings for eight sessions, one leg with a static stretch and the other with a contract-relax technique; half held the pelvis tipped forward, spine long, and half held it tucked, back rounded. The forward-tilt group gained flexibility; the rounded group did not gain significantly with either technique, and the authors concluded that pelvic position mattered more than the method [3]. A later study of 55 adults found that one session of hamstring stretching immediately increased forward pelvic tilt and straight-leg-raise range [4]. Stretching the hamstrings changes how the pelvis moves in a bend. Rounding the lower back changes the lower back.

So the question to ask of any towel, strap or machine is simple: does it let you keep the pelvis tipped forward and the spine long while the legs straighten? Everything else is comfort and convenience, which matter, but second.

What the research says about which stretching method works

Almost everything works, and the best-designed studies could not crown a winner. A systematic review of 28 hamstring stretching trials with 1,338 healthy participants found that every study reported improved range of motion across a variety of techniques, positions and durations; the trials were mostly of poor quality and no single best method could be identified [5]. Position did not decide it: in a four-week trial of 36 adults with short hamstrings, two 30-second stretches four days a week increased hamstring length equally whether done sitting or standing [6]. Technique mattered a little. A 30-second static hold five days a week for six weeks gained about 11 degrees of knee extension, against 4 degrees for a slow active-movement method and under 1 degree for no stretching [7]; at a very low dose, one 30-second stretch three days a week, only plain static stretching beat the control group [8].

Put together: a still hold with the pelvis tipped forward, about 30 seconds, most days. No study has tested a strap or a machine against a towel. What a tool changes is whether you can get into the position those trials used, and whether you keep doing it.

The methods compared

Cost is given in tiers because prices differ by country and change. "Where it fails" is the honest column: every method has a case it does not suit.

Method Spine position Ease and adjustment Cost Where it fails
Hands only (reach for shins or toes) Rounds unless you are already flexible Nothing to set up; no adjustment Free Anyone who cannot reach the feet with a long spine, which is most people with tight hamstrings
Towel round the foot Can be kept long, lying or seated Already in the house; adjust by moving the hands along it Free No repeatable settings; thin ones roll into a cord; when the grip tires the back rounds again
Yoga or stretching strap (buckle or loops) Can be kept long, lying or seated Loops give fixed lengths you can repeat; still held in the hands Low Narrow webbing concentrates the pull on the fingers; nothing holds the posture for you
Doorway or wall (lying, one leg up the frame) Long by default: the floor holds the back flat No grip, no effort; adjust by shuffling closer to the wall Free Needs a free doorway; one leg at a time; teaches nothing about sitting tall
Lying with a strap (supine) Long by default: the floor supports the lumbar spine Safest version for sore backs and beginners; adjust by hand position Free to low One leg at a time; does not train the seated posture you need for sitting and bending
Leg-stretching machines and boards Varies; many invite leaning forward with a round back A crank or ratchet sets the angle; strong, passive stretch Mid to high Bulky, built for side splits rather than the forward bend; the machine, not the muscle, sets the limit
FlexBuddy (two wooden bars and an adjustable strap) Long by design: you sit tall, lean back and tilt the hips against the strap Foot bar under both feet, wooden handles in the hands; big steps by loop, small steps by rolling the strap round the hand bar Low to mid Not a splits tool; one size (142 to 198 cm); the foot bar can slip if you wear shoes, so go barefoot or in socks

Hands, towel and strap are the same tool at three price points. One sceptical FlexBuddy customer put the counter-argument plainly: "a towel would do the same thing." For the lying stretch, that is true. Where the towel disappoints is control: no fixed lengths, so every session is a guess, and when the hands tire the body rounds the back again. A strap's loops let you repeat a setting, but the pull still runs through narrow webbing into the hands, which is what customers mean by rope burn, and nothing holds the posture. For lying stretches, a strap is as good as it gets. For seated stretches, it depends on your discipline.

Leg stretchers and machines, where "hamstring stretch machine" searches lead, are mostly split trainers: a seat with two leg rests that a crank pushes apart. They are built for side splits, a different goal from the forward bend, many invite leaning forward with a rounded back, and because a mechanism sets the angle it is easy to go past the point a muscle would have stopped you at. If your goal is a split, they have a place. If your goal is to bend forward without your back doing the work, they solve a problem you do not have.

FlexBuddy is a bar-and-strap device used sitting or lying down. The argument for it over a strap is not that the hamstrings stretch differently; they do not. It is that the posture is built in: you sit tall, lean back against the strap and tilt the hips forward, so the pull comes from the leaning body rather than from a bent back reaching for the feet. The wooden handles spread the load, and the two-step adjustment lets a stiff beginner start long and shorten by a notch a week. It is not a splits tool. One trainer called it "a great tool to help your clients maintain a neutral spine while stretching calves, hamstrings and lower back," which is the whole claim in one sentence.

How to do the lying hamstring stretch with a strap or towel

Learn this version first, whatever you own. The floor holds your back in position so you can concentrate on the legs.

  1. Lie on your back on a mat or in bed. Bend the other leg and put that foot flat; this keeps the lower back settled.
  2. Loop the towel, strap or foot bar round the sole of one foot, just below the toes, and hold it with both arms long. Shoulders and head stay down.
  3. Raise the straight leg until you feel a clear pull in the back of the thigh. The knee stays straight or very slightly soft.
  4. Check the back: lower back on the floor, tailbone down. If the hips lift or roll, you have gone too high.
  5. Hold for about 30 seconds, breathing slowly; ten slow breaths is a good clock [9]. Lower, rest, repeat two or three times, then change legs.

Stop at mild tightness, never pain. A muscle being hurt contracts against you.

A step up: contract-relax

Once the plain hold is easy, add a contract-relax cycle, the technique physiotherapists call PNF: at the top of the stretch, push the foot gently down into the strap without letting it move for about six seconds, then relax and take the leg a little higher [10]. Contractions at 20 to 60 per cent of maximum work about as well as all-out effort [10][11]; strong ones can cause soreness, so keep this for after exercise and use it with care if you are older [10].

How to do the seated hamstring stretch properly

The seated version is the one to own, because sitting tall and folding from the hips is exactly what tight hamstrings stop you doing in daily life, and it is where a tool matters most: gravity is no longer holding your back straight for you.

  1. Sit on the floor with both legs straight. If you cannot sit upright like that, sit on a folded blanket; raising the hips tips the pelvis forward.
  2. Loop the towel, strap or foot bar round the soles of the feet and hold it with straight arms. Do not pull with bent elbows.
  3. Lift the chest, draw the shoulders down, look ahead. Now lean the whole trunk back against the strap and tilt the hips forward, as if pointing your sitting bones at the wall behind you. That tilt is the stretch; you may feel it with the body still almost upright, and that is correct.
  4. Hold for about 30 seconds, ten slow breaths [9]. If the lower back complains, you have rounded: come up, re-lengthen, settle for a smaller angle.
  5. Rest 30 seconds and repeat, three holds in total. Shorten the strap only when a setting feels calm.

Measure progress by how short the strap can be with a long back, not by how close your nose gets to your knees. Seated and standing stretches gave equal gains in the trial that compared them [6], so if the floor is difficult the same rules apply to a heel on a low step.

Hold times, repetitions and how often

In 93 adults with short hamstrings stretching five days a week for six weeks, a 30-second hold improved knee extension as much as a 60-second hold, and once a day was as good as three times a day [9]. The American College of Sports Medicine recommends about 60 seconds per exercise for each major muscle-tendon group on at least two days a week [12], usually summarised as two to three days a week; 60 seconds can be 15 seconds four times or 20 seconds three times [13]. A clinical review adds that people over 65 gained more from 60-second holds in one study, and that static stretching immediately before explosive sport can reduce strength and jump performance, so long holds belong after training [11].

Expect the first weeks to change what you tolerate rather than how long the muscle is: gains after programmes of three to eight weeks are mostly a change in sensation [14]. That is why a short daily habit beats an occasional long session, and why the tool you will actually use beats the one with the best specification. More in how long to hold a stretch.

Towel and strap mistakes

  • Pulling the foot towards you instead of leaning away. Pulling bends the elbows, hunches the shoulders and rounds the back. Keep the arms straight and let the trunk lean back. The lean is the stretch.
  • Looping it round the arch or the heel. The strap belongs round the ball of the foot. Round the heel it slides off; round the arch it loads the calf first.
  • Letting the knee bend to reach. A bent knee hides that you have gone too far. Slightly soft is fine; bent means take the strap longer.
  • Rounding when the hands tire. The towel's weakness. When the grip gives, the body saves the position by curling the spine. The fix is a shorter session, handles, or a tool that holds the posture for you.
  • Chasing the toes. Progress is a shorter strap with a long back, not a nose nearer the knee. A customer eight weeks in and not yet at his toes, "with progress", had it right.

When a device is worth it, and when it is not

A device is not worth it if you can already sit tall and hold your feet, if your stretching happens lying in bed and a towel suits you, or if your real goal is a split. Nor if your tightness burns down the leg or came on suddenly; that is a nerve or an injury, and the right first purchase is a physiotherapy appointment. The hamstrings and lower back guide covers how to tell the two apart.

A device earns its place when one of three things is true. You have caught yourself rounding: you know the position, you cannot hold it, and the towel is not stopping you. Adjustment is the problem: you want to repeat yesterday's setting and go one notch shorter, not guess every day. Or, most honestly, comfort decides whether you do it at all; a strap that cuts into the fingers stays in the drawer. The tool that wins is the one you still pick up in week six. If you are a complete beginner, start with the best hamstring stretches for beginners and a bath towel, and give it two weeks. If the stretch keeps landing in your back, that is your answer.

Doing this with FlexBuddy

FlexBuddy® is a patented stretching device: two beech-wood bars joined by an adjustable natural-cotton strap, about 32 by 7 by 5 cm, so it fits in a bag. One bar goes under the soles of both feet; the other is held in both hands. The posture from this article is built in: shorten the strap to your current flexibility, sit straight, lean back and tilt the hips forward, shoulders down, chest lifted, arms straight. The strap carries the pull, so the back does not round to reach. Big changes of length come from moving the foot bar to another loop, fine changes from rolling the strap round the hand bar, so you can repeat a setting and shorten it one notch at a time. The wooden handles spread the load instead of a narrow strap cutting in. The brand's routine is ten deep breaths, a 30-second pause, three times. One size covers 142 to 198 cm. A verified buyer wrote: "I am 64 and have never touched my toes. FlexBuddy changed that in a week!" Lifetime warranty, 30-day money-back guarantee. See FlexBuddy, read how to use it, or take the quiz.

Frequently asked questions

How do I do a hamstring stretch with a strap?

Lie on your back, loop the strap round the ball of one foot, keep the other knee bent, and raise the straight leg with long arms until the back of the thigh pulls. Lower back on the floor, hold about 30 seconds, two or three times per leg [9]. Seated, sit tall, lean back against the strap and tilt the hips forward instead of pulling.

Does a towel hamstring stretch work as well as a strap?

For the lying stretch, yes: the towel holds the foot while the spine stays long, which is the whole job. A strap repeats a setting and is kinder to the hands. No trial has compared the two; the position of the pelvis matters more than what is round your foot [3].

Stretching strap vs towel: which should I buy?

Start with the towel you own. Buy a strap if the towel slips or cuts into your fingers. Consider a device with handles if the seated stretch keeps rounding your back whatever you hold.

Do hamstring stretch machines work?

Machines sold as leg stretchers are mostly split trainers that push the legs apart. They train a different movement from the forward bend, and a crank makes it easy to stretch past a sensible limit. Hamstring flexibility improves with simple static stretches in many positions [5], so a machine is not needed for this problem.

Can I do a lying hamstring stretch with a band?

Yes, but an elastic band stretches as you pull, so the leg is never held still. For a static hold, a non-stretch strap, a towel or a bar-and-strap device keeps the leg in place, which is what the 30-second holds in the research used [9][7].

Can I do the hamstring stretch with a towel lying on my bed?

Yes, and for a sore back it is the best place to start, because the mattress supports the spine. Follow the lying steps and keep the hips on the bed; a firm mattress is better than one that lets the pelvis sink and tuck.

This article is general information, not medical advice. Tight muscles usually respond well to regular stretching. If your pain is sharp, radiates down a leg, comes with numbness, weakness, fever, bladder or bowel changes, follows an injury, or keeps getting worse, see a doctor or physiotherapist before you stretch.

References

  1. Esola MA, McClure PW, Fitzgerald GK, Siegler S. Analysis of lumbar spine and hip motion during forward bending in subjects with and without a history of low back pain. Spine. 1996;21(1):71–78. doi:10.1097/00007632-199601010-00017. PMID 9122766.
  2. Muyor JM, Vaquero-Cristóbal R, Alacid F, López-Miñarro PA. Criterion-related validity of sit-and-reach and toe-touch tests as a measure of hamstring extensibility in athletes. J Strength Cond Res. 2014;28(2):546–555. doi:10.1519/JSC.0b013e31829b54fb. PMID 24476746.
  3. Sullivan MK, Dejulia JJ, Worrell TW. Effect of pelvic position and stretching method on hamstring muscle flexibility. Med Sci Sports Exerc. 1992;24(12):1383–1389. PMID 1470022.
  4. López-Miñarro PA, Muyor JM, Belmonte F, Alacid F. Acute effects of hamstring stretching on sagittal spinal curvatures and pelvic tilt. J Hum Kinet. 2012;31:69–78. doi:10.2478/v10078-012-0007-7. PMID 23486214; PMC3588653.
  5. Decoster LC, Cleland J, Altieri C, Russell P. The effects of hamstring stretching on range of motion: a systematic literature review. J Orthop Sports Phys Ther. 2005;35(6):377–387. doi:10.2519/jospt.2005.35.6.377. PMID 16001909.
  6. Borman NP, Trudelle-Jackson E, Smith SS. Effect of stretch positions on hamstring muscle length, lumbar flexion range of motion, and lumbar curvature in healthy adults. Physiother Theory Pract. 2011;27(2):146–154. doi:10.3109/09593981003703030. PMID 20690869.
  7. Bandy WD, Irion JM, Briggler M. The effect of static stretch and dynamic range of motion training on the flexibility of the hamstring muscles. J Orthop Sports Phys Ther. 1998;27(4):295–300. doi:10.2519/jospt.1998.27.4.295. PMID 9549713.
  8. Davis DS, Ashby PE, McCale KL, McQuain JA, Wine JM. The effectiveness of 3 stretching techniques on hamstring flexibility using consistent stretching parameters. J Strength Cond Res. 2005;19(1):27–32. doi:10.1519/14273.1. PMID 15705041.
  9. Bandy WD, Irion JM, Briggler M. The effect of time and frequency of static stretching on flexibility of the hamstring muscles. Phys Ther. 1997;77(10):1090–1096. doi:10.1093/ptj/77.10.1090. PMID 9327823.
  10. Hindle KB, Whitcomb TJ, Briggs WO, Hong J. Proprioceptive neuromuscular facilitation (PNF): its mechanisms and effects on range of motion and muscular function. J Hum Kinet. 2012;31:105–113. doi:10.2478/v10078-012-0011-y. PMID 23487249; PMC3588663. https://pmc.ncbi.nlm.nih.gov/articles/PMC3588663/ (accessed 4 Nov 2026).
  11. Page P. Current concepts in muscle stretching for exercise and rehabilitation. Int J Sports Phys Ther. 2012;7(1):109–119. PMID 22319684; PMC3273886. https://pmc.ncbi.nlm.nih.gov/articles/PMC3273886/ (accessed 4 Nov 2026).
  12. Garber CE, Blissmer B, Deschenes MR, et al.; American College of Sports Medicine. Position stand: quantity and quality of exercise for developing and maintaining cardiorespiratory, musculoskeletal, and neuromotor fitness in apparently healthy adults. Med Sci Sports Exerc. 2011;43(7):1334–1359. doi:10.1249/MSS.0b013e318213fefb. PMID 21694556.
  13. Harvard Health Publishing. The ideal stretching routine. Harvard Medical School, 16 Mar 2026 (reviewed by H. E. LeWine, MD). https://www.health.harvard.edu/staying-healthy/the-ideal-stretching-routine (accessed 4 Nov 2026).
  14. Weppler CH, Magnusson SP. Increasing muscle extensibility: a matter of increasing length or modifying sensation? Phys Ther. 2010;90(3):438–449. doi:10.2522/ptj.20090012. PMID 20075147.
Tagged: beginners flexbuddy exercises flexibility hamstring stretches hamstrings lower back stretching stretching strap tools yoga strap
Older articles Back to Blog Newer articles