To get the most out of a squat, you generally want to go as deep as your mobility allows. But going past your available hip range often causes the pelvis to tuck under, flattening or rounding the lumbar spine. This is the butt wink.

A small amount at maximum depth is considered normal for many lifters. The concern grows when the rounding happens early in the squat, or when it’s pronounced under heavier loads, since that shifts stress onto the lumbar discs rather than the hips and legs.

This is also why it’s easy to miss. It tends to happen in a split second at the very bottom, not throughout the whole movement, so a quick glance in the mirror often won’t catch it.

If your hips don’t have full range of motion, sinking too low into your squat can result in the pelvis tucking backward simply because the hip joint has run out of room. Your spine ends up making up the difference.

This is partly anatomical. Hip socket depth varies from person to person, and limited hip mobility from tight musculature or a tight joint capsule can pull the pelvis into an awkward position well before full depth is reached.

• Hip flexor stretches to open up the front of the hip
• Couch stretch or pigeon pose for deeper hip opening
• Elevating your heels slightly as a short-term workaround

A weak or absent brace reduces spinal stability, and without proper intra-abdominal pressure, your lower back compensates for the missing support throughout the squat.

Bracing typically means taking a big breath into your belly before descending and holding that pressure through the entire rep, sometimes called the Valsalva maneuver in strength training contexts.

Skipping this step, especially under heavier loads, leaves your spine without the internal support it needs, and that gap tends to show up as next-day soreness focused on the lower back.

Standing up from the bottom of a squat should come primarily from your glutes and hips, not your lower back. A weak core or underused glutes can cause the lower back to take on more of the lifting load than it should.

This often shows up as the lifter’s hips shooting up faster than their chest, a pattern sometimes called a “good morning” squat, where the lower back ends up doing work that the hips were supposed to handle.

Over time, this repeated pattern adds up. Even without one specific injury moment, the cumulative strain can leave the lower back consistently sore after squat sessions.

Not every twinge after squats points to a structural problem. Acute low back pain isn’t a serious medical issue in the vast majority of cases, and general soreness after a tough session is common and usually resolves within a few days.

That said, the type of pain matters. Soreness that feels similar to soreness in your glutes or hamstrings, and that fades within a few days, leans toward normal training fatigue rather than injury.

Pain that radiates down the leg, comes with numbness or tingling, or persists well beyond a normal recovery window is a different signal, and that’s worth getting checked rather than working through.