The hip thrust works the glutes first, with the hamstrings second — the Zyra Workouts catalog lists no other muscle for it. It is a hip extension performed with the upper back on a bench and the knees bent, and the bent knees are the point: they keep the hamstrings short, so the glutes have to do the extending. The glute bridge is the same movement from the floor.
Muscles worked
| Hip thrust | Glute bridge | Cable glute kickback | |
|---|---|---|---|
| Primary | Glutes | Glutes | Glutes |
| Secondary | Hamstrings | Hamstrings | Hamstrings |
| Category | Compound | Compound | Isolation |
| Equipment | Barbell | Barbell | Cable |
| Unilateral | No | No | Yes |
| Default rest | 150 s | 120 s | 60 s |
| Step | 2.5 kg | 2.5 kg | 2 kg |
Each working set of any of the three credits 1 set to glutes and 0.5 to hamstrings against the weekly landmarks (10 each).
Hip thrust vs glute bridge
Same muscles, different range. With the shoulder blades on a bench the hips start below bench height and finish in line with the knees and shoulders — a long arc. From the floor the hips start on the ground and finish a hand-width higher — a short arc, mostly the top of the range. The catalog reflects the difference only in rest (150 s vs 120 s) and in the site's load-chart buckets (hip thrust 60–200 kg, glute bridge 40–140 kg); the targets and the step are identical. The two rows keep separate histories, so a bridge PR does not move the hip thrust wand.
What one EMG study measured
Contreras and colleagues compared the barbell hip thrust with the back squat in 13 trained women, each lifting an estimated 10-rep maximum in both exercises. Mean upper gluteus maximus EMG was 69.5% of a maximal voluntary contraction during the hip thrust versus 29.4% during the squat (peak 172% vs 84.9%); the lower gluteus maximus and the biceps femoris (a hamstring) were also higher in the hip thrust, while vastus lateralis (a quad) did not differ significantly (mean 99.5% vs 110%)1. That is a measurement of how electrically active the muscle was during the set — the authors themselves note that training studies are needed to know whether it translates to strength or size. So we leave it as what it is: at a matched 10RM, the hip thrust puts the glutes to work harder per rep.
Setup and execution
Hip thrust. Sit on the floor with the shoulder blades against a bench, bar across the hips (a pad helps), feet flat about shoulder width so that at the top the shins are vertical. Chin tucked, ribs down. Drive through the heels until the hips are level with the knees and shoulders, pause, lower under control until the hips are near the floor. Log the total bar weight.
Glute bridge. Lie flat, bar across the hips, feet flat and close to the hips. Push the hips up until the body is straight from knees to shoulders, pause, lower. Shorter range, so expect more reps or more load at the same effort.
Cable kickback. Low pulley, ankle strap, hands on the frame. Kick the working leg straight back from the hip without arching, return under control, finish all reps and switch. Tap L/R in the logger so each side has its own line — the Bulgarian split squat guide explains how those lines count.
Rep and RIR targets by goal
The hip thrust and glute bridge are compound exercises:
| Goal | Reps | RIR | Rep ceiling | Sets (beginner / intermediate / advanced) |
|---|---|---|---|---|
| Strength | 3–5 | 2 | 6 | 3 / 4 / 5 |
| Hypertrophy | 6–10 | 2 | 10 | 2 / 3 / 4 |
| General | 8–12 | 2 | 12 | 2 / 3 / 4 |
The kickback is an isolation exercise:
| Goal | Reps | RIR | Rep ceiling | Sets (beginner / intermediate / advanced) |
|---|---|---|---|---|
| Strength | 6–8 | 2 | 9 | 2 / 3 / 3 |
| Hypertrophy | 10–15 | 1 | 14 | 2 / 3 / 3 |
| General | 8–12 | 2 | 12 | 2 / 3 / 3 |
The rep ceiling is the number the app compares your last set against: the midpoint of the rep range plus the RIR target (round((min + max) / 2) + RIR). RIR is reps in reserve — how many more reps you could have done. These targets are the app's defaults, not a law; a program you build yourself can set anything.
How progression steps on this exercise
Barbell rows move by one pair of the smallest plate — 2.5 kg with 1.25 kg plates in your gym profile. On the hypertrophy target (6–10 @RIR 2, ceiling 10): 100 kg × 11 → 102.5 kg × 6; 100 kg × 8 → hold; 100 kg × 5 → 97.5 kg × 6. The cable kickback moves 2 kg per step on the stack. This is arithmetic from the progression engine, not a trial result. Estimated 1RM pages exist for the hip thrust and the glute bridge; the kickback has one too, though a per-side isolation 1RM is more curiosity than plan.
Alternatives
The swap list for the hip thrust keeps the primary muscle (glutes): the glute bridge first (compound, barbell — full marks), then the reverse lunge (compound, dumbbell), then the cable glute kickback (isolation). The list is short because only four catalog rows are filed under glutes. Exercises that many people think of as glute work — the deadlift, the Romanian deadlift, the back squat — are filed under back or quads and credit the glutes at half weight as secondaries.
The short version
Glutes primary, hamstrings secondary; bent knees keep it that way. Hip thrust from a bench (long range, 150 s), glute bridge from the floor (short range, 120 s), kickback per side on a cable. Compound targets, 2.5 kg barbell steps. One EMG study: more glute activity than the back squat at a matched 10RM, equal quads — a measurement, not a verdict. Educational overview only — training guidance, not medical advice.