Low-Bar Squat

Low bar placement — called the "Power Back Squat" in the source, the low-bar squat in current terminology (see bar-placement) — sets the bar across the posterior deltoids rather than on top of the trapezius (high-bar). This forces a greater forward torso lean and hip hinge, shifting the line of force toward the hips. The result is more posterior-chain loading (glutes, hamstrings, adductor magnus) and a shorter effective range of motion, which is why low-bar is generally favored in powerlifting for handling heavier loads. The vasti still extend the knee substantially, but rectus femoris — a 2-joint hip-flexor/knee-extensor — contributes less here than in the high-bar back squat, since its hip-flexor end is lengthened by the greater forward lean.

The general squat-safety rules still apply: do not lock out the knee, maintain proper spinal alignment (semi-isometric, "S" not "C"), squat to near-parallel, and understand the femur-vs-torso-length and knee-toe relationships (see knee-squat-safety).

• Bar placement: low, across the posterior deltoids (vs. high-bar on the traps).
• Primary: glutes, hamstrings (all three), vasti (three quads); Secondary: rectus femoris, adductor magnus.
• More forward lean and hip hinge than the high-bar back squat.
• Shorter effective ROM; generally preferred in powerlifting for heavier loads.
• Same squat-safety rules apply (no lock-out, spinal alignment, near-parallel depth).

• bar-placement — high/low/front bar placement and the terminology note.
• knee-squat-safety — general squat-safety rules.
• quadriceps / hamstrings / gluteus-maximus — the muscles whose relative emphasis shifts with bar placement.
• back-squat — the high-bar sibling.
• front-squat — the bar-in-front sibling.