The lumbar and sacrum movement pattern during the back squat exercise.

Area of Science:

• Biomechanics
• Kinesiology
• Strength and Conditioning

Background:

• The squat exercise is fundamental for lower limb strength training.
• Lumbar lordosis changes during squats often signal the end of the descent, but lumbar-sacrum segment behavior is not fully understood.

Purpose of the Study:

• To quantify lumbar-sacrum movements during the back squat.
• To investigate the influence of stance width on sacrum movement during squats.

Main Methods:

• Thirty trained individuals (18 men, 12 women) performed narrow and wide stance squats with 50% bodyweight load.
• Three-dimensional measurements of lumbar angle (T12/L1), sacrum angle (L5/S1), and lumbar flexion (lordosis) during ascent and descent phases were recorded.

Main Results:

• Men and women showed similar lumbar angles across stances and phases.
• Significant differences (p < 0.05) in sacrum angles, lumbar flexion, and timing were observed between genders and stance widths.
• Men exhibited significantly greater lumbar flexion range (26.3°–25.4°) than women (12.9°–12.6°) during descent.

Conclusions:

• Gender-specific movement patterns exist during squatting, impacting strength development and screening.
• The lumbar spine tends to become kyphotic under load, challenging traditional cues to maintain lumbar curvature.