The Hamstring Curl For a Strong and Tight Backside

Sports fans are all too familiar with the scene: a beloved player dashing across the field, leaving their opponents in the dust, and the crowd roaring with anticipation as they prepare to score. However, all too often, the player collapses seemingly out of nowhere, gripping the back of their thigh in agony. This injury is a hamstring strain and can be incredibly painful and debilitating.

The hamstrings—a collection of three muscles extending from your sit bones to the backs of your knees—are among the most frequently injured muscles in sports. A study on NFL players reported 1,716 hamstring injuries over a 10-year period, which breaks down to roughly five or six injuries per team per season. The numbers are similar in pro soccer and basketball and among regular people in recreational sports.

If you’re an athlete or a weekend warrior who likes to run fast, jump high, and train hard, your hamstrings are at risk. If you’re a desk jockey who spends most of your day at a computer, you may be even worse off, especially if you plan to get in shape or be more active again. A 2017 study of college students found that 82% of the subjects had tight hamstrings due to prolonged sitting—and these were young adults with a mean age of 20.

Finally, if you’re a gym rat who’s long made the mistake of focusing your leg training on the fronts of your thighs—hitting the hammies as an afterthought—you’ve already lit the fuse that can lead to a hamstring blowout. A study in Isokinetics and Exercise Science showed that quad and hamstring strength imbalances were associated with non-contact leg injuries.

We understand how important it is to have solid and healthy hamstrings. To help you remain injury-free and maximize your performance, we have created a comprehensive tutorial on strengthening and protecting your hamstrings.

Hamstring Anatomy

You probably know that your hamstrings run down the back of your thigh, but you may not know that they’re a group of different muscles working together. The three muscles that make up this group are the biceps femoris, semimembranosus, and semitendinosus.

All three run from the lower portion of the hip bones to just below the knee on the posterior aspect of the leg. The biceps femoris runs down the lateral part of the posterior thigh, while the semimembranosus and semitendinosus run down the medial side. While the individual muscles can be targeted to a certain extent, all three typically work together.

Since the hamstrings are a biarticular muscle group (they cross more than one joint), they’re primarily responsible for performing hip extension and knee flexion. This isn’t to say that they must be doing both actions simultaneously, but simply that they can perform hip extension and knee flexion either in isolation or simultaneously. The hamstrings also work with several other muscles to perform internal rotation at the hip. 

What are hamstrings, and how do we curl them? 

Hamstring curls refer to any exercise involving pulling your heels towards your butt due to knee flexion. Do you love tightening the sleeves on your t-shirts by banging out bicep curls? Think of hamstring curls as the same thing for your lower body. They’ll strengthen your lower body, give you resilient hips and knees, and help you build a more esthetically pleasing backside.

The Hamstring Curl

Step by Step Instructions for a hamstring gym machine:

1. Adjust the height and depth of the foot pad to ensure your legs are almost but not quite square, with the pad touching just above the posterior aspect of your ankles. You want the legs to be as straight as possible without hyperextending.
2. Pick an appropriate weight. I recommend doing this now because it will be much more difficult once you’re completely locked in.
3. Bring the support pad down so that it rests on your quads.
4. Imagine you’re wearing a belt buckle and trying to pull that buckle towards your belly button using only your abs. This helps to put your hips into a neutral position, allowing you to complete the curls effectively.
5. Firmly grab onto the handles, point your toes to the sky and begin pulling your heels down towards your butt.
6. Come as far down as your mobility allows and hold for a second.
7. Allow your feet to move away from your body towards the starting position. This should be slow and controlled the whole time.
8. Congrats, you just did an excellent hamstring curl. Repeat that same rep another 5-12 times.

Benefits of Hamstring Curls

Here are some benefits of hamstring curls that will put your mind at ease.

• Posture – Far too many people only work the muscles they can see in the mirror. This trend tends to leave them exceptionally anteriorly dominant. Their quads, pecs, and abs may pop, but their backside is neglected. Not only can this make us look a bit uneven, but it can also put us at risk for injuries. The combination of overdeveloped quads and underdeveloped hamstrings can predispose many to anterior pelvic tilt. This posture puts the hamstrings in a chronically lengthened position, leaving them in a disadvantageous position to absorb and produce force effectively and safely.
• Knee Health – Another significant benefit of strengthening the hamstrings is the ability to help stabilize the knee joint. Due to the hamstrings’ origin and insertion, they can aid in ACL injury prevention. Much like the ACL inside the joint, the hamstrings aim to keep the tibia (shin bone) in a safe position concerning the femur (thigh bone) when quickly decelerating and cutting. As you would imagine, having solid and resilient hamstrings is highly beneficial for field-based athletes who perform a rapid change of direction.
• “Tight” Hamstrings – Often, hamstrings that are thought to be “tight” are loose. Anterior pelvic tilt puts them in a chronically lengthened position, making them feel tight when they’re stretched 24/7 and need a more concentric orientation. Strengthening them through various hamstring curl variations can help pull them back into a more neutral, stable position.
• Building a Sexy Backside – Dedicate your time and energy to strengthening your hamstrings and transforming your backside into a show-stopping masterpiece. Your backside will be strong and stunning, and you’ll be proud of the results.

Common Mistakes

Even though it’s a relatively simple exercise, many people can (and will) make some mistakes that will put a damper on all that hard work. Here are a few things to avoid when building your hammies:

• Trying to max out a hamstring curl is usually an isolation movement. This means there is not much benefit or risk when loading them maximally.
• Curling when the hips are in anterior pelvic tilt – Since the hamstrings are attached to the hips, people with anterior pelvic tilt can end up with a strange sensation of tightness when their hamstrings are actually in a lengthened position. If your hips are dumped forward and stretching only seems to make your hamstrings feel tighter, you probably need to focus more on gaining strength in both your rectus abdominis and your hammies. Over time, this should return your hamstrings to a more appropriate resting position.
• Using the calves – When completing a hamstring curl, many people point their toes down. This activates the claves, taking much of the work away from the hamstrings. To isolate the hammies, point your toes towards your shins to disadvantage the calf muscles. This is called dorsiflexion. Your ability to remain in dorsiflexion will rely mainly on your hamstring strength and the exercise. Staying dorsiflexed for the entirety of the rep will be much more difficult (and somewhat impractical) for exercises such as walkouts that rely on other muscles for stability.
• Failing to use full ROM – See above… Using heavy weights may make you feel cool, but it puts you at a disadvantage if you can’t control them. When the weight is too heavy, you’re only working in the midrange. This is where the muscle is at its strongest. You also want to use the full range of motion to challenge the hammies at their fully lengthened and shortened positions. Pick a weight that allows you to get a full stretch at the bottom and complete contraction at the top.

Other Hamstring Exercises

The following are the best hamstring builders, organized by their primary function.

Hip Extension

In these movements, the hamstrings work with the glutes to push your thigh bones from a flexed position (knee pulled up in front of you) to an extended one (knees moving away from your body). The movement is known as a hinge, and it helps you run faster, jump higher, and maintain a pain-free back. 

Romanian Deadlift

Step 1: Set a barbell on a rack at about the hip level. Grasp the bar with a shoulder-width grip and take it off the rack. Step back and plant your feet hip-width apart. Draw your shoulders together and downward (think: “proud chest”).

Step 2: Take a deep breath, draw your ribs down, and brace your core. Push your hips backward and, maintaining a long spine from your head to your pelvis, lower your body until you feel a stretch in your hamstrings. Actively pull the bar into your body, so it stays in contact with your legs the entire time. Allow your knees to bend slightly as you lower down.

Step 3: Squeeze your glutes as you extend your hips and come back up.

Back Extension

Step 1: Adjust the pad on the back extension bench so that when you lie on it, the top edge lines up with the crease in your hips. Using the handles for support, set up on the bench so your hips rest on the pad, your ankles are braced by the ankle pads, and your feet rest against the foot plate about hip-width apart.

Step 2: Turn your toes outward slightly. Interlace your fingers behind your head, spread your elbows wide, and keep them there throughout the movement. Bend at the hips to lower your torso toward the floor, stopping before your lower back rounds. Your head, spine, and pelvis should form a straight line.

Step 3: Take a deep breath into your belly and brace your core. Now squeeze your glutes and hamstrings and extend your hips to raise your torso until your body forms a straight line from your head to your feet.

If body weight alone is too easy, add resistance by holding a dumbbell.

Kettlebell Swing

Step 1: Place a kettlebell on the floor and stand about two feet behind it with feet shoulder-width apart.

Step 2: Draw your shoulder blades together and downward (think: “proud chest”). Draw your ribs down and tuck your tailbone slightly to make your pelvis level with the floor. Brace your abs.

Step 3: Bend your hips backward to lower your torso and grasp the kettlebell handle with both hands.

Step 4: Keeping a long line from your head to your pelvis and your shoulder blades pressing downward toward your back pockets, shift your weight to your heels. Bend your knees slightly, lift the kettlebell off the floor, and hike it back between your legs.

Step 5: When your wrists make contact with your inner thighs, forcefully contract your hamstrings and glutes and thrust your hips forward, coming into a standing position and swinging the kettlebell forward and up to about eye level. Let the kettlebell swing back between your legs, folding at the hips and bending your knees slightly as the kettlebell swings down and back to begin the next rep.

Do not lift the kettlebell with your upper body, as if performing a front raise shoulder exercise. The swing is an explosive movement, and the glutes and hamstrings must perform almost all of the work.