Lie on your back, bend your knees, and place your feet hip-width apart (heels close to your buttocks); let your arms rest relaxed by your sides. Actively push your pelvis upwards until your shoulders, hips and knees form a straight line. Hold this position without letting your hips drop. Continue to breathe calmly and keep your buttocks engaged.
Attention:
Do not arch your back at the top of the movement (the load should be on your lower back rather than your buttocks); engage your buttocks, not your lower back; do not place your heels too far apart or too close together (incorrect muscle activation); do not let your knees cave in; do not let your pelvis tilt uncontrollably; do not hold your breath.
Lighten:
Lift your hips only slightly; place your hands on the floor for support; bring both feet slightly closer to your bottom (for better control of the lift).
Harden:
Single-leg variation (single-leg glute bridge hold); place weight on the pelvis (e.g. dumbbell or weight plate); place heels on an unstable surface (e.g. ball); position heels further away from the body (greater leverage).
Variation:
Cross one leg over the other or extend one leg in line with the upper body (Setup = 2 exercises/work both sides).