Leg Press vs Squat: Strength, Muscle Growth, and Joint Load Compared

Leg press vs squat comes down to your goal. For a stronger barbell squat or a higher jump, squat: in two training studies, squats carried over better to both. For bigger quads and glutes without a bar on your back, the leg press does the job well, and one lab study measured generally lower knee forces than in the squat. Neither does much for the hamstrings, and if you have access to both, doing both is usually the best answer. Our leg press machine guide covers machine types, sizes, and costs.

Leg press vs squat at a glance

Strength: squats carry over, the press mostly doesn’t

You get best at the movement you practice. A 2025 meta-analysis of 43 studies found that dynamic training improved dynamic strength with about twice the effect size it had on untrained isometric tests. The same pattern shows up when squats and leg presses go head to head:

• Squat strength. In a 10-week trial, strength-matched participants did squats only, leg presses only, or both, for 6 sets of 8 to 12 reps twice a week. Squat training carried over to maximal squat strength better than the leg press.
• Jumping. In an 8-week study of 78 students, 39 of whom trained, parallel squats raised squat jump height by 12.4% and countermovement jump height by 12.0%. The 45-degree leg press group’s gains of 3.5% and 0.5% weren’t significant.
• Power vs force. Ten sportsmen in a force-velocity study produced more maximal power and velocity in the squat, but more theoretical maximal force in the leg press.

Your leg press number won’t predict your squat well, either. In a study of 60 men, 45-degree leg press 10-rep max explained about 25% of the variation in squat 10-rep max among novices and about 55% among advanced lifters. Part of the gap is the machine: on a 45-degree sled, only about 71% of the plate weight acts along the rails, while in a squat you also lift most of your body weight. Our leg press sled weight guide walks through that math.

Muscle growth: what each lift builds

Quads

In a 2026 MRI study, 17 untrained adults trained one leg on the leg press and the other on the knee extension for 12 weeks. The press grew the three vasti by 4.4 to 6.2% and the whole quadriceps by 4.9%, comparable to the knee extension. The rectus femoris, which also crosses the hip, grew just 1.1% on the press, against 13.2% with knee extensions.

Squats build the quads too. A 9-week trial randomized untrained college-age adults to squats (16 people) or hip thrusts (18 people), and MRI showed greater quad and adductor growth with squats. In a flywheel study of 9 strength-trained people, quad activity was similar in a maximal squat and a horizontal leg press. We found no trial comparing long-term quad growth from the two directly.

Glutes and adductors

In the MRI study, the press grew the gluteus maximus by 15.4% and the adductor magnus by 6.2%, while the knee extension grew neither. In the 9-week trial, squats and hip thrusts produced similar glute growth. A 2025 meta-analysis of 12 glute studies concluded that parallel or full-depth squats and leg press machines can both increase gluteus maximus size.

Hamstrings

The squat produces more hamstring activity: about twice as much as the leg press in a 1998 study of 10 men, and more again in a 2001 study of 10 experienced lifters. But activity isn’t growth. In the 9-week trial, the hamstrings showed little to no growth with squats, and the leg press MRI abstract doesn’t list them among the muscles that grew. Whichever you choose, add a leg curl, a Romanian deadlift, or a glute-ham raise.

Fatigue per session

In a 2025 trial, 12 physically active men did 5 sets at a 10-rep max on a Smith machine squat and a horizontal leg press. Total work was higher on the squat, 43.0 vs 29.1 kJ, and so were cortisol, growth hormone, and mid-session lactate, yet quad fatigue was similar and everything had recovered within 24 hours. That’s one small study using a Smith machine, not a free barbell.

Knees: what the force data shows

The 1998 Escamilla study estimated forces inside the knee from video, force transducers, muscle activity, and a muscle model. In the 2001 study, compressive forces on the knee joint and kneecap, and tension in the posterior cruciate ligament (PCL), were generally greater in the squat than in either leg press variation. No ACL forces showed up in either exercise.

In both lifts, those forces rose as the knee bent further, and the authors suggested the 0 to 50 degree range for anyone who wants to minimize them. They advised caution with the squat for people with PCL or kneecap problems, especially at deeper angles. In the flywheel study, the knee extension moment was considerably greater in the squat, and its authors suggested the press may be preferable for training and injury risk, though that rests on 9 people.

These are modeled forces in healthy lifters, not injury rates, and no study we found tracked knee injuries in squatters versus pressers. The press’s practical advantage for a sore knee is control: the guided path makes it easier to stop at a depth that feels fine. With a diagnosed knee problem, ask a clinician which range suits you.

Lower back: different kinds of load

In a squat, the bar sits on your spine. An old modeling study of 4 people estimated L3-L4 compression of 6 to 10 times body weight in half squats with 0.8 to 1.6 times body weight on the bar, with trunk lean mattering most. In 13 people doing Smith machine squats at 80% of one-rep max, MRI showed signs of greater stress on the lowest lumbar discs after parallel squats than after half squats. Both are small, acute measurements, not evidence that squats injure backs.

The press takes the bar off your back, but not your back out of the equation. ISSA’s leg press guide warns that lowering the sled too far lifts your buttocks and lower back off the pad, rounding your lumbar spine. In a second flywheel study of 11 people at a set submaximal effort, the horizontal leg press was loaded more than twice as heavily as the squat and produced greater joint moments and forces at the ankle, hip, and lower back.

Machine design matters too. In a pressure-mat study of 15 people pressing half their body weight, back pad shape changed how pressure spread across the mid and lower back, and the authors estimated that an adjustable support could cut peak pressure by up to 26% compared with a flat one.

You don’t need extreme depth to grow your quads on the press. In an 8-week study of 23 trained people, a knee range of about 5 to 100 degrees grew quad thickness as well as the full range of about 5 to 154 degrees. Stopping where your hips stay on the pad costs you little.

Practical differences

• Equipment. A squat needs a barbell, plates, and a rack with safety arms or pins; see our power rack guide. A press needs a dedicated machine, usually plus plates. Check our home leg press machine picks and leg press machine dimensions, or a leg press/hack squat combo for both movements on one frame.
• Skill. ISSA describes the press as useful for novices, people returning from injury, and as an accessory for advanced lifters, but notes it doesn’t train stabilizing muscles the way free weights do.
• Training alone. A press has built-in safety stops. Don’t push a squat to failure alone without set safeties.
• Tracking progress. Leg press loads don’t transfer between machines, because rail angle, sled weight, and friction differ.

How to choose, or combine them

This is our judgment from the evidence above, not a study result:

• You want a bigger squat, or compete in powerlifting: make the squat your main lift, with the press as extra quad work.
• You jump or play a sport: favor the squat, though no study here measured sport performance directly.
• You want bigger legs: either works. Add knee extensions for the rectus femoris and a hamstring exercise.
• Your knees or back limit you: the press, with depth you control, is often the easier start.
• You train alone at home: a press is simpler to push hard safely, but a rack trains far more than legs.

You don’t have to choose. In the 10-week trial, the group that did both was among the better groups on effect sizes for both jumping and balance, though no difference was significant, and the authors concluded that both free weights and machines can improve functional outcomes. If you do both in one session, start with the lift you most want to improve. That’s programming logic, not a study finding.

Safety for both lifts

• Squat inside a rack. Set the safety arms or pins just below your lowest position.
• Keep your hips on the pad when you press. Find where your hips start to curl up, and stop above it.
• Don’t lock your knees at the top of a press. ISSA and Motra both list this as a common mistake.
• Keep your knees tracking over your feet, and lighten the load if they cave inward.
• Keep your heels down. Our leg press foot placement guide covers setup in detail.
• Re-engage the leg press safeties after every set, and never reach under a loaded sled unless it’s locked.
• Stop if you feel sharp pain. If you have a back, hip, or knee condition, talk to a physician or physical therapist first.