TRX Hamstring Curl
What Is the TRX Hamstring Curl?
TRX Hamstring Curl is a compound exercise that primarily targets the hamstrings and also engages the calves, the glutes and the core muscles that hold your hips off the floor. It is an intermediate-level movement done lying on your back with your heels in the foot cradles of a suspension trainer: you lift your hips just off the floor and pull your heels in toward your glutes, then straighten your legs again without letting the hips touch down.
The TRX Hamstring Curl trains the knee-bending job of the hamstrings with nothing more than a set of straps, which makes it a practical stand-in for a leg curl machine in home, travel and outdoor workouts. It usually sits later in a lower-body session as accessory work, and it pairs well with a hip-hinge such as the Barbell Romanian Deadlift, which works the same muscles through the hip instead of the knee. On the same straps, the TRX Squat covers the front of the legs.
The hamstrings bend the knees and, together with the glutes, keep the pelvis lifted, while the calves help bend the knee and hold the feet steady in the cradles. In the version shown, the hips stay at the same low height and bend as the heels come in, so the thighs finish close to vertical. That keeps the hamstrings from being fully shortened at the top. Driving the hips higher into a bridge as you curl makes the exercise harder and adds glute work, and curling with one leg at a time is the next step up. Because each strap moves on its own and can swing in any direction, the hips and trunk also have to keep both feet moving together, which is the main difference from the Exercise Ball Leg Curl, where both feet share one surface that rolls in a straight line.
It suits anyone who wants more hamstring work without a machine, and it is a common step between floor bridges and harder bodyweight curls such as the Nordic Hamstring Curl. Before starting, you should be able to hold a steady Glute Bridge without your lower back arching. If holding the hips up while the straps move is still too hard, build up with the Exercise Ball Leg Curl first.
Muscles Worked
- Biceps Femoris
- Primary
- Semimembranosus
- Primary
- Semitendinosus
- Primary
- Gluteus Maximus
- Medium
- External Oblique
- Minimal
Instructions
- Fix the suspension trainer to a secure overhead anchor, adjust both straps to the same length and lengthen them until the foot cradles hang at about mid-calf height.
- Lie on your back with your head away from the anchor and place your heels in the foot cradles, positioned so the straps hang straight down.
- Straighten your legs with your feet together and your toes pulled up toward your shins. Rest your arms on the floor by your sides, palms down.
- Brace your core, press your heels down into the cradles and lift your hips just off the floor, so your body forms a straight line from your shoulders to your heels.
- Bend your knees and pull your heels in toward your glutes, letting your hips bend as your knees rise toward the ceiling. Keep your hips off the floor and both feet moving together.
- Stop when your thighs are close to vertical and pause briefly.
- Slowly straighten your legs back to the start, keeping your hips off the floor and the straps from swinging.
- Repeat for the desired reps, then lower your hips to the floor and take your heels out of the cradles.
Common Mistakes
Dropping the hips between reps
Letting the hips rest on the floor at the bottom of each rep releases the tension on the hamstrings between reps, so keep the hips hovering for the whole set.
Arching the lower back
Pushing the belly up to keep the hips high loads the lower back instead of the hamstrings, so brace your core and keep your ribs down.
Sawing the straps
Pressing harder with one foot than the other makes the cradles swing up and down, so push evenly through both heels and slow down until the straps stay steady.
Snapping the legs straight
Letting the legs shoot back out after the curl skips the slow lowering that does much of the work and jerks the hamstrings at full stretch.
Cutting the curl short
Stopping with the knees only slightly bent turns the set into a hip hold, so pull your heels in until your thighs are close to vertical.
Injuries
TRX Hamstring Curl is a low risk exercise when performed with proper technique. You lift only part of your body weight, your shoulders and arms stay on the floor, and you can end a set at any point by lowering your hips. Most problems come from cramping or from losing the hip position, not from the load itself.
The main strain points are the back of the thigh, the calves and the lower back. Hamstring and calf cramps are common when the muscles are new to bodyweight curls or near the end of a hard set. Arching the lower back to keep the hips up moves the effort from the hamstrings to the spine, and letting the legs snap straight at speed jerks the hamstrings at their longest point. Brace your core so the ribs stay down, lower every rep slowly and warm the hamstrings up first. Before every session, check that the anchor is fixed to a solid beam, bar or door anchor on the closed side of a door, that the buckles are locked and that both straps are the same length, and seat your heels fully in the foot cradles so they cannot slip out mid-rep.
To make it easier, shorten the range of each curl, slow it down and build strength with a Glute Bridge or the Exercise Ball Leg Curl. To progress, drive your hips higher as your heels come in, slow the lowering phase, move on to a single-leg curl, or work up to the Nordic Hamstring Curl.
Stop the set if you feel a sharp or sudden pain in the back of the thigh or behind the knee, a cramp that does not ease when you lower your hips and straighten your legs, or low-back pain you cannot remove by bracing.
- Primary Focus
- Hamstrings
- Equipment
- Suspension trainer and body weight
- Modality
- Strength
- Difficulty
- Intermediate
Alternative Exercises
Frequently Asked Questions
- Q: What strap length should I use for the TRX Hamstring Curl?
Set both straps to the same length so the foot cradles hang at about mid-calf height. Lie with your heels in the cradles directly under the anchor, so the straps hang straight down at the start of each rep.
- Q: Should my hips stay off the floor between reps?
Yes. Keep them just off the floor for the whole set, and let them bend as your heels come in so your thighs finish close to vertical. Pushing the hips higher into a bridge as you curl is a harder version, not a requirement.
- Q: Why do my calves work so hard during the TRX Hamstring Curl?
Your calf muscles cross the back of the knee, so they help bend it, and they also hold your feet steady in the cradles. In a study of 21 physically active adults with suspension training experience who did a TRX hamstring curl with their feet pointed, the calf muscles worked at a higher share of their maximum than the hamstrings. If your calves cramp, cut the set short and build the reps up over a few sessions.
- Q: How is the TRX Hamstring Curl different from the Exercise Ball Leg Curl?
On the Exercise Ball Leg Curl both feet sit on one ball that rolls in a straight line, which makes it steadier. The TRX straps move separately and can swing in any direction, so your hips and trunk have to work harder to keep both feet moving together.
- Q: How do I make the TRX Hamstring Curl harder?
Drive your hips higher as your heels come in, take three or four seconds to straighten your legs, or curl with one leg at a time. Add one change at a time, and only once the two-leg curl stays smooth with the straps steady.