How much weight should I use compared with the two-leg leg press?

Start with roughly half of what you use on the two-leg press and adjust from there. Many people find each leg can handle a little more than half, because a leg working alone often produces slightly more force than it does alongside the other, but control and full range come first.

Does training one leg at a time build strength as well as the two-leg leg press?

For leg press strength, it appears to. In a five-week study of adolescent rugby players, single-leg pressing on a 45-degree plate-loaded leg press raised two-leg leg press strength as much as two-leg training did and raised single-leg strength more, though neither group improved its sprint or jump performance.

What should I do with my other leg?

Rest that foot flat on the floor or on the machine frame in front of the seat with the knee bent and relaxed. It is there only to keep you steady, so it should not push.

Where should I put my foot on the platform?

The middle of the platform, in line with the hip, is the standard position. Placing the foot higher brings in more glutes and hamstrings, while placing it lower bends the knee further and puts more of the work on the quads.

Which leg should I start with?

Start with your weaker leg and match its reps on the stronger side. That way the weaker leg sets the workload, which helps narrow the difference between sides over time.

Machine Single-Leg Leg Press

What Is the Machine Single-Leg Leg Press?

Machine Single-Leg Leg Press is a compound exercise that primarily targets the quads and also engages the glutes, adductors and hamstrings. It is a beginner-level movement performed one leg at a time on an angled, plate-loaded leg press, with the backrest supporting the torso and the hands holding the handles beside the seat while the free leg rests out of the way.

Working one leg at a time lets each side do its full share of the work, so the stronger leg cannot quietly cover for the weaker one. That makes it a practical way to build leg strength and size while spotting and evening out differences between sides, and the total load is far lighter than a two-leg press, which keeps the demand on the lower back modest. It usually sits after the main squat or hinge of a lower-body session, or as the main knee-dominant lift for people who train mostly on machines.

Like the two-leg Machine Leg Press, it loads the knee and hip extensors together. When untrained adults pressed one leg at a time on a seated leg press machine for 12 weeks, the vastus lateralis and vastus medialis grew about as much as with leg extensions, the gluteus maximus and adductor magnus grew as well, but the rectus femoris barely changed. Pair it with the Machine Single-Leg Leg Extension when the front of the thigh is a priority. Foot position shifts the emphasis: a higher foot on the platform brings in more glutes and hamstrings, while a lower foot bends the knee further and biases the quads.

It suits beginners who want unilateral work without the balance demand of a Dumbbell Bulgarian Split Squat, lifters rounding out a quad-focused program and anyone with a noticeable strength gap between legs. If one leg cannot control the platform through a full range, build up first with the two-leg Machine Leg Press and lighter single-leg sets.

Muscles Worked

MuscleActivation

Vastus Lateralis: Primary
Vastus Medialis: Primary
Gluteus Maximus: High
Adductor Magnus: Medium
Rectus Femoris: Medium
Biceps Femoris: Low
Gluteus Medius: Low
Semitendinosus: Low
Soleus: Low
Gastrocnemius (Medial Head): Minimal

Instructions

Load the weight plates onto the machine and sit with your back and head flat against the reclined backrest and your hips pressed into the seat.
Hold the handles beside the seat.
Place your working foot flat on the middle of the platform, in line with your hip, with the toes pointing up or turned slightly out.
Bend your other leg and rest that foot flat on the floor or the machine frame in front of the seat.
Press the platform up a little with your working leg and release the safety locks so the platform moves freely.
Bend your working knee and lower the platform under control, letting the thigh come toward your chest while the knee tracks over the toes.
Stop at the deepest point you can reach with your hips and lower back still flat on the pad.
Drive through your heel and midfoot to press the platform back up until the leg is almost straight, without locking the knee.
Keep both hips square on the seat throughout and let the free leg rest without pushing.
After the last rep, press the platform to the top, engage the safety locks and make sure they hold before taking your foot off. Repeat on the other leg.

Common Mistakes

Locking the knee
Snapping the working knee straight at the top shifts the load from the muscles onto the joint, so stop just short of full extension.
Going too deep
Lowering the platform until the pelvis tucks and the lower back lifts off the pad puts the spine under load in a rounded position.
Knee caving inward
Letting the knee drift toward the midline as you press strains the inside of the knee, so keep it tracking over the toes.
Twisting the hips
Rotating the pelvis or lifting one hip off the seat lets the torso help the press and loads the lower back unevenly.
Helping with the free leg
Pushing off the floor or the frame with the non-working foot takes work away from the leg you are training.
Lifting the heel
Pressing through the toes with the heel off the platform loads the front of the knee and makes the foot unstable.

Injuries

Machine Single-Leg Leg Press is a low risk exercise when performed with proper technique. The backrest supports the torso and the total load is lighter than a two-leg press, but the knee, the lower back and the hip of the working side still take strain when the range or the load gets ahead of control.

The knee is stressed most when it snaps into a locked position at the top or caves inward under load, so stop just short of a straight leg and keep the knee in line with the toes. The lower back is at risk at the bottom: if the platform comes so close that the pelvis tucks under and the lower back peels off the pad, the spine ends up bearing load in a rounded position. Keep the depth to what you can reach with the hips and lower back flat on the pad, and keep both hips square on the seat rather than letting the torso twist toward the working side. Release the machine's safety locks only once the foot is set, and engage them again before taking the foot off the platform.

To regress, return to the two-leg Machine Leg Press, lighten the load or shorten the range to a pain-free depth. To progress, add load gradually, slow the lowering phase or pause briefly at the bottom, then move on to free-standing single-leg work such as the Dumbbell Bulgarian Split Squat. Stop the set if you feel sharp pain in the knee, a pinch at the front of the hip, pain in the lower back, or numbness or tingling down the leg.

Overview

Primary Focus: Quads
Equipment: Machine
Modality: Strength
Difficulty: Beginner

Alternative Exercises

Frequently Asked Questions

Q: How much weight should I use compared with the two-leg leg press?: Start with roughly half of what you use on the two-leg press and adjust from there. Many people find each leg can handle a little more than half, because a leg working alone often produces slightly more force than it does alongside the other, but control and full range come first.
Q: Does training one leg at a time build strength as well as the two-leg leg press?: For leg press strength, it appears to. In a five-week study of adolescent rugby players, single-leg pressing on a 45-degree plate-loaded leg press raised two-leg leg press strength as much as two-leg training did and raised single-leg strength more, though neither group improved its sprint or jump performance.
Q: What should I do with my other leg?: Rest that foot flat on the floor or on the machine frame in front of the seat with the knee bent and relaxed. It is there only to keep you steady, so it should not push.
Q: Where should I put my foot on the platform?: The middle of the platform, in line with the hip, is the standard position. Placing the foot higher brings in more glutes and hamstrings, while placing it lower bends the knee further and puts more of the work on the quads.
Q: Which leg should I start with?: Start with your weaker leg and match its reps on the stronger side. That way the weaker leg sets the workload, which helps narrow the difference between sides over time.