Squats vs deadlifts: knees or hips, what each built in a trial, and whether you need both

The squat and the deadlift are both heavy lower-body barbell lifts, and they look close enough that people ask whether one can stand in for the other. In the lab they behaved as different movements: the squat put more of the work through the knees, and the deadlift more through the hips. This page covers what the studies measured in each, what six weeks of training each one built, the fatigue and hormone readings, and how to fit both into a week.

How to do each lift is on squat form and deadlift form. Where they sit in a session is on leg day.

Squats vs deadlifts at a glance

Muscles worked: knees against hips

• The joint loads. 28 resistance-trained adults, 17 men and 11 women, lifted 70 and 85% of their max on each lift while motion capture measured the loads at each joint. The deadlift produced a larger peak hip-extensor moment (about 3.59 against 2.98 newton-metres per kilogram of body weight) and more positive work at the hip. The squat produced a larger knee-extensor moment (about 2.14 against 1.18) and about four times the positive work at the knee.¹ The authors' reading: the deadlift for people targeting the hip extensors, the squat for the knee extensors.¹
• The movement itself. In 25 lifters filmed at a regional powerlifting meet, the two lifts differed in bar speed and in hip, knee and ankle angles at the sticking point. The authors described the squat as a simultaneous movement and the deadlift as a sequential one, and concluded the lifts are markedly different, with no direct cross-over between them.²
• The lower back. In 16 people lifting 80% of their max, the squat produced about 34.5% more activity than the deadlift in the erector muscles low on the spine (lumbar-sacral), and the deadlift about 12.9% more higher up (upper lumbar). Activity in the abs and obliques didn't change.³ So both work the muscles along your spine; the core workout covers what they leave out.

The trap-bar deadlift sits between the two. In 16 resistance-trained people, 6 men and 10 women, the hex bar allowed a heavier one-rep max than the back squat, with more forward lean and less knee bend, and the squat produced the higher hip moment of the two; knee moments didn't differ.⁷ That's a different comparison from the straight-bar deadlift above. The trap bar section of deadlift form has the rest.

What six weeks of each built

In the one head-to-head training trial found for this page, 25 resistance-trained men with more than three years of training were randomly split into a deadlift group (14) and a squat group (11). Three of the deadlift group withdrew within the first four weeks, so the results below come from the 22 men who finished.⁴ Both groups trained three times a week for six weeks, with the deadlift or the squat as their only heavy lower-body lift, and both programs included jumps.⁴

• Each got strongest at its own lift. The squat group's squat max rose about 15.2% against 5.7% in the deadlift group; the deadlift group's deadlift max rose about 17.7% against 6.7% in the squat group.⁴
• Jumping improved about the same. Jump performance rose in both groups, with no difference between them.⁴
• Thigh size didn't change measurably. Thigh cross-sectional area showed no significant change over the six weeks in either group.⁴

The authors' conclusion was that both lifts produced similar gains in lower-body strength and jumping and both belong in strength programs.⁴ The pattern matches the one on how to get stronger: you get strongest at the lift you practise. Squat training also carries over to the deadlift to a degree. In a nine-week trial of 34 untrained college-aged adults, a squat group and a hip-thrust group raised their three-rep-max deadlift by similar amounts.⁸

Is the deadlift more tiring than the squat?

Not in the two studies that measured it.

• Straight after a heavy session. 10 resistance-trained men did eight sets of two at 95% of their max on each lift. Thigh strength dropped after both, with no difference between the lifts in central fatigue (the nervous system's drive to the muscle). The squat left more fatigue in the thigh muscle itself, even though the deadlift sessions moved more total weight.⁵
• Over the next four days. 12 well-trained men did four sets to failure at 80% of their max on the squat, the bench press and the deadlift in separate weeks. Soreness, swelling and blood markers of muscle damage followed the same time course for all three; bar speed dropped for up to 72 hours after the squat and didn't drop after the deadlift.⁶ Rest days covers recovery more widely.

Barnes's authors concluded that separate planning for the two lifts "may be unnecessary" when both are used to build strength.⁵

What these studies didn't test

The training trial lasted six weeks in trained men and found no measurable change in thigh size, so it doesn't answer which lift builds more muscle over months. The joint-load, movement and muscle-activity studies were single sessions, mostly in experienced lifters. Apart from the hip-thrust trial, none of them tested people new to lifting. So the comparisons here describe how the lifts differ and what short blocks of each built, not what either will do for you.

How to choose, or use both

As a practical guide, not a finding:

• Want a bigger squat or deadlift number: train that lift. The trial above found strength followed the lift trained.
• Want both: keep both, on separate days or on the same day with the one you care about more first. Each loads what the other loads less: the squat the knees, the deadlift the hips.
• Only room for one heavy lift a session: alternate them, a squat day and a deadlift day.
• New to both: learn the squat pattern and the hinge first, light. Hinge first covers the deadlift side.

If either lift brings sharp pain, not just effort, stop and see a doctor or a physical therapist.

Common questions

Squats vs deadlifts: which muscles do they work?

Both work the hip and knee extensors and the muscles along the spine. The squat loads the knee extensors (the quads) more, and the deadlift the hip extensors (the glutes and hamstrings) more.¹ Lower-back activity was higher low on the spine in the squat and higher up in the deadlift.³

Squats or deadlifts for glutes?

No study found for this page compared glute growth from squats and from deadlifts. The deadlift put a larger load on the hip extensors, which include the glutes.¹ And squat training grew the glutes about as much as hip-thrust training did in the nine-week trial above, measured by MRI.⁸ The hip thrust and leg day for glutes cover the rest.

Do squats or deadlifts raise testosterone more?

In the one study that compared them, neither changed it. After eight sets of two at 95% of their max on each lift, 10 resistance-trained men showed no change in salivary testosterone or cortisol.⁵ This page makes no hormone claim beyond that measurement.

Is the deadlift harder than the squat?

It moved more weight in the one study that compared heavy sessions: in Barnes 2019 the deadlift sessions lifted a greater load and more total weight.⁵ But it left no more central fatigue than the squat, and four days of recovery followed the same course for both.^5,6

Can I squat and deadlift on the same day?

Nothing above rules it out. The authors of the fatigue study concluded that separate planning for the two may be unnecessary, and recovery over four days followed the same course for both.^5,6 Put the one you most want to get stronger at first in the session (practical), and keep the second one lighter or lower in sets if your legs are spent.

Can one replace the other?

Not fully. The lifts move differently and loaded different joints, and strength followed the lift trained.^2,1,4 Each group also improved a little at the other lift, about 6 to 7%.⁴

If you'd rather not plan it alone

Choosing between the squat and the deadlift is easy next to fitting both, and their recovery, around the rest of your week. Coaching is the version where your workouts live in the Trainerize app, built around the days you actually have, and a weekly call looks at the week you just had and rebuilds the next one. Coaching to get stronger explains how that works, and here's how to apply. Otherwise: put a squat on one day this week and a deadlift on another, three sets each, and log both.