The single leg leg press follows the same basic motion as the standard leg press, but with one foot on the plate instead of two. It’s one of the most effective ways to build leg strength evenly on both sides, and the setup is straightforward once you know the key details.
Machine Setup
Start by adjusting the seat so your knee forms roughly a 90-degree angle when your foot is flat on the plate. If the seat is too far back, you’ll struggle to reach full depth. Too close, and your knee will travel past your toes at the bottom of the movement, putting unnecessary stress on the joint.
Make sure your back and glutes are pressed firmly against the pad before you begin. This contact point is non-negotiable. Once your hips lift off the seat, your lower back rounds and absorbs force it shouldn’t be handling. If you find your glutes peeling off the pad at the bottom of a rep, the weight is too heavy or you’re going too deep for your current mobility.
Step-by-Step Execution
Place one foot in the center of the foot plate. Your toes should point straight ahead or angle out very slightly. Let your non-working leg rest on the machine frame or hold it slightly elevated, whichever feels more stable and keeps it out of the way.
Unlock the sled and slowly bend your knee, lowering the weight until your knee reaches about 90 degrees of bend. Keep your knee tracking in line with your middle toes throughout the entire movement. This is where people run into trouble: the knee wants to cave inward when only one leg is working, and fighting that tendency is half the benefit of the exercise.
Press through your heel to push the weight back up. Straighten your leg until it’s nearly locked out, but stop just short. Fully locking the knee shifts the load off your muscles and onto the joint itself. Inhale on the way down, exhale as you push up. Keep your core braced and your torso upright against the pad for the entire set. Complete all reps on one side before switching.
Where You Place Your Foot Matters
For single leg work, the general recommendation is to position your foot vertically centered on the plate, shifted slightly toward the side of the working leg. But moving your foot higher or lower on the plate changes which muscles do most of the work.
A low foot position emphasizes your quadriceps heavily, with roughly 70% of the effort coming from the quads, 20% from the glutes, and 10% from the hamstrings. This is the variation that will burn the front of your thigh the most.
A high foot position flips the emphasis toward your posterior chain: about 45% glutes, 35% hamstrings, and only 20% quads. If you’re trying to build your glutes with this exercise, place your foot higher on the plate and focus on driving through the heel.
If you’re new to the single leg version, start with your foot centered. You can experiment with placement once the movement pattern feels natural.
Muscles Worked
Your quadriceps do the primary work of extending the knee against resistance. The hamstrings play a supporting role, controlling the descent and stabilizing the knee joint. Your glutes activate to stabilize your pelvis and assist with the pressing motion, especially at the bottom of the rep where your hip is most flexed.
What makes the single leg version different from the standard leg press is the stability demand. When both legs share the load, your stronger side can quietly compensate for the weaker one. Working one leg at a time eliminates that compensation, forcing your core, lower back, and the small stabilizer muscles around your hip and knee to work harder to keep everything aligned. Over time, this evens out strength differences between your left and right sides.
Machine Types and How They Differ
The 45-degree leg press is the most common version. You sit at a reclined angle and push a weighted sled upward along angled rails. This setup allows heavier loads and works well for single leg pressing, though the sled can feel unstable when you first try it with one foot.
Horizontal leg press machines have you sitting upright and pushing the weight straight out in front of you. These tend to be more back-friendly and more beginner-friendly, making them a good starting point for single leg work. The range of motion feels slightly different because gravity acts on the weight differently, but the movement pattern and muscle recruitment are similar.
Some cable-based multi-gym stations include a leg press option. These work fine for single leg pressing but typically don’t allow the same heavy loading as plate-loaded machines.
Common Mistakes to Avoid
The most frequent error is lowering the sled too far. When you go past the point where your back and glutes can stay flat against the pad, your lumbar spine rounds under load. This is the primary injury risk on any leg press variation, and it’s easier to make this mistake on single leg work because the lighter load makes you feel like you can go deeper. Set your depth based on where your form breaks down, not on how far the machine allows you to go.
Letting your knee cave inward is the second biggest issue. Without a second leg sharing the load, the working knee tends to drift toward the midline of your body, especially as you fatigue. Actively push your knee outward so it stays aligned with your toes. If you can’t maintain that alignment, reduce the weight.
Other common problems include hyperextending the knee at the top of each rep, overarching the lower back, and lifting the hips off the seat. All of these shift stress away from the muscles you’re trying to train and onto joints and spinal structures that aren’t built for it.
Sets, Reps, and Weight Selection
Start with roughly half the weight you’d use for the two-legged version, then adjust from there. Most people find they can handle slightly more than half per leg, since the bilateral version involves some inefficiency between the two sides.
For building muscle size, 8 to 12 reps per set at a moderately challenging weight is the traditional recommendation, though research shows muscle growth can occur across a wide range of rep schemes as long as you’re working hard enough. Three to four sets per leg is a solid starting point.
For pure strength, heavier loads in the 1 to 5 rep range are more effective. For muscular endurance, lighter loads at 15 or more reps per set work best. Because the single leg press already demands more stability and control, most people benefit from staying in the moderate rep range (8 to 12) until they’re very comfortable with the movement.
When choosing your starting weight, err on the lighter side. The balance challenge of working one leg at a time makes the exercise harder than the numbers suggest. You can always add weight once your form is solid through the full range of motion.