PHOENIX
Pendulum Squat vs Hack Squat: The Honest Comparison
A pendulum squat moves the load on a fixed arc from an arm that pivots at the top of the frame, so you squat upright and the hardest part of the rep is the bottom. A hack squat moves a sled in a straight line on angled rails, so you recline against a back pad and the hardest part is mid range to lockout. Buy the pendulum squat for deep, upright, quad and glute work with minimal lower back load. Buy the hack squat for heavy sled loads and a quad focused leg station members already know how to use.
The comparison at a glance
| Factor | Pendulum squat | Hack squat |
|---|---|---|
| Load path | Fixed arc on a pivoting arm | Straight sled on angled guide rails |
| Torso position | Upright, shoulders under a harness | Reclined against a back pad |
| Hardest point | Bottom of the rep and the drive out | Mid range to lockout |
| Depth | Full squat depth with an upright chest | Limited by the sled angle |
| Lower back load | Minimal | Low to moderate |
| Knee and hip loading | Hips and knees share the work, knees loaded hardest at the bottom | Knees lead, with the back pad taking the hips out of it |
| Feel | Brutal on the quads at modest plate loads | Heavy, familiar, rewards big loads |
| Best for | Quad and glute development without spinal load | Quad focus, heavy sled loads, members who already know the movement |
The arc does the thinking for you.
On a pendulum squat you stand on an angled footplate with your shoulders under a padded harness. The load hangs on an arm that pivots from the top of the frame. As you squat, the arm swings through an arc. Because the resistance follows that arc rather than going straight up and down, your torso stays upright and the work goes through the hips and knees instead of being braced through the spine.
The arc also changes where the effort lands. The hardest part of a pendulum rep is the bottom and the drive out of the hole. Lockout is almost a rest. That is the opposite of most sled machines, and it is why lifters say the pendulum squat is brutal on the quads at far lower plate loads than they would run on a leg press.
Depth is the other win. With the chest up, most people reach full squat depth without the hips tucking under, and members can train the squat pattern to genuine failure with no spotter and no spinal fatigue to carry into the next session.
A straight line and a back pad.
On a hack squat you recline against a back pad with your shoulders under pads and your feet on a platform. The sled runs on angled guide rails. You push, the sled slides up in a straight line, and the back pad takes the load off your lower back the whole way.
Because the path is linear, the load is hardest from mid range to lockout and the bottom is the easier part. That is why a hack squat rewards heavy plates. It is a quad builder first, and the back pad means the hips contribute less than they do on an upright squat.
Sled angle matters here. On the Phoenix machines, the 40 degree sled gives a slightly deeper range and a more upright torso, and the 45 degree sled shifts a little more load onto the posterior chain. Both are plate loaded on guided carriages with multi-position safety catches.
Four things that decide it.
One more honest point. The hack squat is the familiar one. The pendulum squat gets a curious look the first week and a queue by the second.
Rules of thumb before you choose.
- You want one machine to replace the barbell squat pattern for members who should not be loading their spine.
- Your floor is glute and quad focused and you want depth with an upright chest.
- You coach athletes or rehab clients and want hard leg work with minimal lower back cost.
- Your members want heavy sled loads and a pure quad grind from mid range to lockout.
- You need a leg station members can use unsupervised on day one without being shown.
- You are choosing between a 40 and 45 degree sled and want to tune torso angle and posterior chain involvement.
- You are building a premium leg line. Most serious floors run a pendulum squat, a hack squat and a leg press, because each one loads the legs hardest at a different point in the rep.
Plate loaded, commercial steel, built for the abuse.
What is the difference between a pendulum squat and a hack squat?
A pendulum squat moves the load on a fixed arc from a pivoting arm, so you squat upright and the bottom of the rep is hardest. A hack squat moves a sled in a straight line on angled rails, so you recline against a back pad and the mid range to lockout is hardest.
Which is better for quads?
Both build quads. The pendulum squat hits them hardest in the deep position at lower plate loads. The hack squat lets you load heavier and grinds the quads through the mid range and lockout with the hips supported.
Which is easier on the lower back?
The pendulum squat. The upright torso and the arc keep spinal load minimal. A hack squat is low to moderate because the back pad supports you but the bottom position can still round the lower back.
Which machine lets you squat deeper?
The pendulum squat. The arc lets most people reach full squat depth with an upright chest. Hack squat depth is limited by the sled angle.
Should a commercial gym buy a pendulum squat or a hack squat?
If you are buying one machine to replace the barbell squat for members who should not load their spine, buy the pendulum squat. If your members want heavy, familiar sled work, buy the hack squat. Premium floors run both.
What is the difference between a 40 degree and a 45 degree hack squat?
The 40 degree sled gives a slightly deeper range and a more upright torso. The 45 degree sled shifts a little more load onto the posterior chain.
Can't wait? Call 0422 046 895 or email andy@phoenixstrength.com.au and Andy will talk you through it now.