Research
Mixed
Maintaining a neutral spine and upright trunk posture during squats minimizes compressive and shear forces on the lumbar spine, whereas forward lean or lumbar flexion significantly increases injury risk.
Keep your back straight and your chest up when you squat. Leaning forward or rounding your back puts dangerous pressure on your discs and ligaments. If you can't stay upright, lighten the weight.
GoodSupportsHIGH confidence
Squatting with a flexed lumbar spine decreases the moment arm for the lumbar erector spinae, reduces tolerance to compressive load, and results in a transfer of the load from muscles to passive tissues, heightening the risk of disc herniation... shear forces during squatting have been found to be significantly higher as lumbar flexion increases from the neutral position.
Why this rating
Supported by multiple studies on spinal kinetics (Adams, Cappozzo, McGill).
Source
Squatting Kinematics and Kinetics and Their Application to Exercise Performance
Brad J. Schöenfeld · The Journal of Strength and Conditioning Research · 2010
narrative_reviewCited 520×
Read the paper This is one finding among thousands. Every one is graded and traced to its source, so you can see what the evidence actually supports. Browse the research →