Building Your Hamstrings

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Your hamstrings have two jobs, and most people only train one of them.

The hamstrings run down the back of your thigh from your hip to just below your knee. Because they cross both joints, they pull your hips through (hip extension, like standing up from a deadlift) and bend your knee (knee flexion, like a leg curl). Only deadlift, and you miss the knee job. Only curl, and you miss the hip job.

Think of it like a rope tied to two posts. You can pull it tight by moving the top post or the bottom post. A complete hamstring program moves both.

• One Hinge: a hip-dominant movement, like a Romanian deadlift (RDL), a straight-leg deadlift or a 45-degree back extension.
• One Curl: a knee-dominant movement, like a seated or lying leg curl.

Your First Step: Look at your current leg days. If you can't name one hinge and one curl in your week, add the one that's missing.

The Breakdown

Meet the Muscles

"The hamstrings" is a group. The biceps femoris long head and the two inner hamstrings (semitendinosus and semimembranosus) cross both the hip and the knee. The biceps femoris short head only crosses the knee, so hinges barely train it. Curls do. That's the first reason a hinge alone leaves gaps.

Squats and Deadlifts Don't Cover It

Plenty of lifters assume heavy squats take care of the back of the leg. In a 10-week study comparing squat depths, full squats grew the glutes and adductors (inner thighs), but hamstring volume didn't change in a meaningful way (Kubo et al., 2019). The hamstrings work during a squat, but they barely change length, so they never get a big stretch under load.

Conventional and trap-bar deadlifts share the work with your quads and glutes. They're great Meat & Potato Lifts. They're just not a complete hamstring plan.

The Hinge: Where the Stretch Lives

Run your hinge with S.S.I. (Setup, Stabilize, Initiate):

• Setup: feet about hip-width, soft knees, the bar close to your thighs.
• Stabilize: brace your trunk, set your shoulders and keep your back in the same position the whole rep.
• Initiate: push your hips straight back like you're closing a car door with your backside. The weight slides down your legs.

Stop going down when your hips stop moving back. If you have to round your back to get lower, you've run out of hamstring range and started borrowing from your spine. Then drive your hips forward and finish with a full squeeze.

A 45-degree back extension is easier to learn. In one 10-week study, a hip-extension exercise grew the biceps femoris long head more than the Nordic curl did, while both grew the semitendinosus (Bourne et al., 2017). Different exercises, different emphasis.

The Curl: Why Seated Earns Its Spot

If you only have room for one curl, the seated leg curl has the best research behind it. Sitting bends your hips, which puts the hamstrings on a stretch before the knee even moves. One study put one leg on a seated curl and the other on a lying curl for 12 weeks. The seated leg grew more, about 14% versus about 9%, mostly in the muscles that cross the hip (Maeo et al., 2021). Lying curls still worked. Seated curls just worked better.

On any curl, line your knee up with the pivot point, keep your hips on the pad, curl all the way, squeeze, and control the weight back to a full stretch. No bouncing at the bottom, and no half reps. Train the entire strength curve.

Where the Nordic Fits

The Nordic hamstring curl is the kneeling exercise where a partner or strap holds your ankles and you lower your body forward as slowly as you can. Across studies of more than 8,000 athletes, programs that included Nordics cut hamstring injuries roughly in half, though the studies varied a lot (van Dyk et al., 2019). For sprinters, they're worth a serious look. For everyone else, they're optional.

How I Put It Together

My hamstring day starts with my quads. I put a hip band on my knees, cinch myself down with the seat belt on a leg extension, and knock out 30 to 50 reps with both legs. That gets everything primed and ready to go.

Then I go to a lying hamstring curl. My favorite is the Atlantis version, because I love the stretch. I warm up with about 65 pounds (about 29 kilograms) for 20 to 25 reps. Then I add a couple of 10s and scale up, and scale up again, until I'm around 135 pounds (about 61 kilograms). That's where my working sets start: 3 to 5 sets of 8 to 12. Big stretch, big squeeze.

When my range starts to get limited, I move to a Prime hamstring curl and go after the top end. I keep a little weight on the lower pins for the beginning and middle of the range, then burn out the top end, because that's usually where I'm weakest.

After those two, I'm gassed. Hamstrings have always felt like a weaker part for me, so I keep going. I grab a plain barbell with no plates for straight-leg deadlifts, just to dial in form and get a big stretch. Next come standing calf raises to burn my calves out of the equation, because they kick in if I sit in the stretch too long. Then seated hamstring curls. No seated curl, I go standing. No standing curl, I set up a modified standing curl on a leg extension. That's the worst case, but when you're on the move trying different gyms, you pick from what you have.

My favorite part is the opening run: leg extensions with the band and seat belt, into lying curls, into the Prime curl for the top-end squeeze. Seated curls have the stronger research, and they're still on my list. I open with lying because I love that stretch.

You don't need my whole routine. The logic underneath it is what matters: something that loads the hamstrings from the hip, something that loads them from the knee, both taken hard with clean reps.

The Cue That Changes It

Straight-leg deadlifts are a phenomenal exercise, and I love them. The biggest mistake I see is people giving themselves a false impression of their range of motion. They treat it like a stretch where the goal is touching their toes. It isn't.

The cue is to find where your hamstrings turn off. Past that point, people start to hunch, round their back or bend their knees to give themselves the illusion of depth. So I teach what a neutral spine looks like, where their true depth is and what they're actually trying to hit.

When someone just can't grasp it, I take them to a 45-degree back extension. I show them what complete time under tension feels like in the lower back. They get a pump in the spinal erectors and a little glute. Externally rotate the hips a little, and the glutes kick in more. Then I bring them back to the straight-leg deadlift. By then their lower back and glutes are so tired from the other two movements that the only option left is to cue the hamstrings.

It's torture, and it's not a quick fix. But it's a good way to learn the difference between those three muscle groups.

Bro Science Check: "Heavy squats build your whole leg, hamstrings included."

What the Research Says: Ten weeks of full squats grew the glutes and inner thighs, but hamstring size barely moved (Kubo et al., 2019). Seated leg curls, which stretch the hamstrings at the hip, grew them more than lying curls (Maeo et al., 2021).

Verdict: Cut. Squats are a great lift. They are not a hamstring program. Add a hinge and a curl.

When It Isn't Just Tight Hamstrings

A sharp pain high in the back of the thigh during a sprint or a heavy hinge, especially with bruising, is not tightness. Stop, and have it looked at by a doctor or physical therapist. Not medical advice.

When people ask me about my favorite equipment, I tell them one of my favorite hamstring pieces of all time is the Flex Leverage Hamtractor. I've only ever seen it in three gyms. It's a very rare piece that focuses on and activates your hamstrings and puts them in a state of absolute decimation. It's a phenomenal piece of equipment, and probably one of the best hamstring machines ever made. I still don't own one.

P.S. If you ever see one for sale, DM me. I'm not kidding.

Hamstrings and glutes share the hip-extension job, so the two programs work together. For the front of the leg, see Building Your Quads.

Next: Building Your Glutes.

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