Many hack‑squat and leg‑press stations use high‑density, thickened shoulder and back cushions covered with anti‑slip, wear‑resistant material (leather or vinyl) to reduce strain on the shoulders, neck, back, and lumbar areas and improve comfort during heavy or repeated reps.
These machines primarily target the quadriceps, hamstrings, glutes, and calves. Some hybrid trainers and combined movements also engage the core and back.