Strengthening your hamstrings requires a mix of exercises that challenge the muscles in different ways, specifically through both hip extension and knee flexion movements. Most people default to one type of exercise and miss half the equation. A well-rounded approach builds more muscle, protects against injury, and improves performance in everything from sprinting to squatting.
Why Your Hamstrings Need Two Types of Exercise
The hamstrings are a group of four muscle heads running down the back of your thigh. Three of them cross both the hip and the knee, meaning they have two jobs: extending your hip (driving your leg behind you) and flexing your knee (bending it). The fourth, the short head of the biceps femoris, only crosses the knee.
This dual role matters for training. Exercises that emphasize hip extension, like Romanian deadlifts, preferentially activate the biceps femoris (the outer hamstring). Exercises that emphasize knee flexion, like the Nordic hamstring curl, recruit more of the semitendinosus (the inner hamstring). If you only do one category, you’re leaving significant portions of the muscle group undertrained. A complete hamstring program includes at least one hip-dominant and one knee-dominant exercise.
Best Hip-Dominant Exercises
Hip-dominant hamstring exercises involve hinging at the hip while keeping your knees relatively straight. These movements load the hamstrings in a stretched position, which is a powerful driver of muscle growth.
- Romanian deadlift (RDL): The gold standard. Hold a barbell or dumbbells, push your hips back, and lower the weight along your legs until you feel a deep stretch in the hamstrings. Your knees stay slightly bent throughout. This exercise builds the entire posterior chain and is particularly effective for the biceps femoris.
- Single-leg Romanian deadlift: Same movement on one leg. This version is excellent for correcting side-to-side strength imbalances, which are a common risk factor for hamstring strains. Unilateral training improves neuromuscular activation across the hamstrings, glutes, and quadriceps simultaneously.
- Good mornings: A barbell sits across your upper back as you hinge forward. The loading angle is different from the RDL, which provides variety for long-term programming.
- 45-degree hip extension: Using a back extension bench angled at 45 degrees, you hinge at the hip and drive back up. Holding a plate or dumbbell at your chest adds resistance as you get stronger.
Best Knee-Dominant Exercises
Knee-dominant exercises involve bending and straightening the knee against resistance. They isolate the hamstrings more directly and are essential for balanced development.
- Nordic hamstring curl: Kneel on a pad with your ankles anchored, then slowly lower your torso toward the ground, resisting gravity with your hamstrings. This exercise has been studied extensively in athletes and reduces hamstring injury rates by up to 51%. You can start with just the lowering (eccentric) phase if the full movement is too difficult.
- Seated leg curl: If you have access to a gym, the seated leg curl is the superior machine option. Because your hips are flexed at 90 degrees while sitting, the three biarticular hamstrings are placed in a longer, more stretched position compared to the lying (prone) version. Research shows this leads to greater muscle growth: seated leg curls produced a 14% increase in hamstring volume compared to 9% for prone leg curls over the same training period.
- Slider/Swiss ball leg curl: Lie on your back with your heels on sliders or a stability ball, lift your hips, and curl your heels toward your glutes. This is a solid bodyweight option that challenges knee flexion and hip extension simultaneously.
How to Structure Your Training
Aim to train your hamstrings twice per week. Muscle repair takes 48 to 72 hours, so spacing sessions at least two days apart gives you the recovery window you need while still providing enough training stimulus. A simple split: one session focused on a hip-dominant exercise and one on a knee-dominant exercise, or include one of each in both sessions at lower volume.
For building strength and size, work in the 6 to 12 rep range for most exercises. The hamstrings have a roughly even split of fast-twitch and slow-twitch muscle fibers, with considerable variation between individuals. This means they respond well to a range of rep schemes. Heavier sets of 6 to 8 reps and moderate sets of 10 to 12 reps both have a place in your program. Three to four working sets per exercise is a practical starting point.
Progressive overload is the non-negotiable principle. Add weight, add reps, or slow down the eccentric (lowering) portion of each rep over time. Without progression, the muscle has no reason to adapt.
Seated vs. Prone Leg Curls
If your gym has both machines, choose the seated leg curl. The mechanics are straightforward: when you sit with your hips bent, the three hamstring muscles that cross the hip joint start in a lengthened position before the curl even begins. Training a muscle at longer lengths consistently produces more hypertrophy. In a direct comparison, the seated position drove 8% to 24% more growth in each of the biarticular hamstrings. The one muscle that only crosses the knee (the short head of the biceps femoris) grew about the same in both positions, around 9 to 10%.
If you only have a prone (lying) leg curl available, it still works. You can partially replicate the stretched-position benefit by keeping your hips slightly elevated or by pairing it with an RDL, which loads the hamstrings at long muscle lengths through a different movement pattern.
Fixing Strength Imbalances
Most people have one leg that’s noticeably stronger than the other. This asymmetry increases your risk of straining the weaker side. Single-leg exercises are the most direct fix. The single-leg RDL, single-leg leg curl, and single-leg slider curl all force each hamstring to do its own work without the stronger side compensating.
A practical approach: start each set with your weaker leg, match that number of reps on your stronger side, and let the weaker leg dictate the load. Over several weeks, the gap narrows. Research on unilateral training confirms it effectively compensates for bilateral strength deficits and improves overall limb balance.
Reducing Hamstring Injury Risk
Hamstring strains are among the most common muscle injuries in sports, and they have a frustratingly high recurrence rate. The Nordic hamstring curl has the strongest evidence base for prevention, with studies across multiple sports and competitive levels showing a 51% reduction in hamstring injuries per 1,000 hours of activity. The mechanism is straightforward: the exercise builds eccentric strength, which is the hamstring’s ability to resist being forcibly lengthened, exactly what happens during sprinting when your leg swings forward before foot strike.
You don’t need to do high volumes. Two to three sets of 4 to 8 reps, twice per week, is enough to build protective eccentric strength. If you can’t do a full Nordic yet, use a band attached to a rack in front of you for assistance, or simply control the lowering phase for 3 to 5 seconds and push yourself back up with your hands.
A Sample Weekly Plan
Here’s a straightforward way to organize two hamstring-focused sessions per week:
- Session 1: Romanian deadlift, 3 sets of 8 reps. Seated leg curl, 3 sets of 10 to 12 reps.
- Session 2: Nordic hamstring curl, 3 sets of 5 to 6 reps. Single-leg RDL, 3 sets of 8 to 10 reps per leg.
This covers hip extension and knee flexion in both sessions, includes a unilateral exercise for balance, and builds eccentric strength through the Nordic curl. As you progress, increase the load on your RDLs and leg curls by small increments, and work toward performing more controlled reps on the Nordic. Most people see meaningful strength gains within four to six weeks and visible changes in muscle size by eight to twelve weeks with consistent effort.