The simple hamstring curl targets the muscles in the back of your thigh, including the semitendinosus, semimembranosus, and biceps femoris, which make up the hamstrings. These muscles work together to allow you to bend at the knee and move your thigh — critical for walking and running. A hamstring curl, or leg curl, is a simple exercise that involves bending your knees and moving your heels toward your glutes while keeping the rest of your body still. It’s typically done on a leg curl machine, but there are a number of alternatives you can do without going to a gym.  The hamstring curl is a great exercise for runners, but what would 50-a-day do to my legs? I set out to find out. As a reminder, working on the same muscle group every day isn’t recommended as it’s important to give muscles time to recover after putting them under stress. If you’re new to an exercise, or you’re returning to exercise after an injury, it’s a good idea to check your form with a personal trainer before adding reps or weight to the move.  Looking for more workout inspiration? Here’s what happened when this writer did bicep curls every day for a week, plus when our fitness writer challenged her shoulders with 50 Arnold presses a day for a week. 

How to do a hamstring curl 

As mentioned in the intro, I mainly focused on variations that didn’t involve going to the gym. Here are a few options: Standing hamstring curl: This is the most simple form of hamstring curl. Stand with your feet hip-width apart, and shift your weight to your left leg. Bend your right knee, bringing your heel up to your right glute, then slowly lower your leg back to your starting position. Complete all the reps on one side before moving on to the opposite leg.  Prone hamstring curl: To do a prone hamstring curl, use a long resistance band and loop it around something stable. Lying on your stomach, loop the resistance band around one heel, with your ankle flexed. Pull against the resistance band to lower your heel to your glutes. Pause, then straighten your leg back to your starting position. Dumbbell hamstring curl: To do a dumbbell hamstring curl, hold a dumbbell in between your feet and curl both feet up toward your glutes, then lower back to your starting position. You can also use a set of the best ankle weights if you don’t have a dumbbell on hand.  

I did 50 hamstring curls a day for a week — here’s what happened 

As a runner, strong legs are important when it comes to getting faster and avoiding injury, but after 350 hamstring curls over a week, here are the lessons learned: 

I realized how lazy my hamstrings and glutes have gotten

Like many runners, I suffer from weak glutes, and I realized very quickly how quad-dominant I’d become as a runner on my first 50 hamstring curls. I opted to add a resistance band and do prone hamstring curls, and I could definitely feel the back of my legs working hard during the move. I also noticed quickly that one leg was a lot stronger than the other — I’m right-handed, and tend to lead from my right leg, but doing single-leg hamstring curls really highlighted my left side was weaker.  If you’re looking for a set of the best resistance bands for training at home, we’ve found them here. You’ll want a long band for this exercise. 

I enjoyed the variety of this exercise

During some of these week-long challenges, I’m sick to death of the exercise by Day Two. The joy of hamstring curls was the ability to mix things up each day. I grabbed a set of ankle weights and did standing hamstring curls one day, placed a dumbbell between my feet on another, and even used a yoga ball to perform leg curls, resting my feet on the ball and raising my hips and legs off the floor, then rolling the ball into my glutes. One day I even went to the gym to do them on the leg curl machine, but I preferred using resistance bands and weights. Whether you’re at home or in the gym, this is a move that can easily be adjusted or modified. 

Adding resistance and weight upped the ante

I found using resistance bands and weights helped increase the load on the hamstrings during this exercise. When using a heavier weight, it’s important to think about pressing your belly button into the mat to avoid arching your back and putting pressure on your spine.

I won’t be doing them every day, but I will be adding them to my leg workouts in the future

By the end of this week, I definitely felt this move in my hamstrings. No physio would recommend hammering the same muscle group every single day, so while I’ll definitely be adding hamstring curls to my leg workouts in the future, I’m looking forward to taking a break for now.  Looking for more leg day inspiration? Check out this 7-move kettlebell leg workout to build bigger legs, as well as this 7-minute resistance bands glute workout.