PrimarySecondaryNot worked
This movement mainly trains glutes, and also recruits Hamstrings, Spinal erectors, adductors.
The extension isolates what the squat and press share: the hip alone, knee nearly fixed. Glute max works without the quads or the erectors inviting themselves in.
Twelve to twenty reps per leg, moderate load. An end-of-session complement, not a substitute for heavy bilateral work.
Arching the lower back to get more range behind you. The extension then comes from the spine rather than the hip, and the glute stops where you thought it was starting.
The variants REPWIND's catalogue carries, under the name the app shows:
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