The squat is often called the "king of strength training" — it activates over 70% of your body's muscle groups in a single movement. But it's also one of the highest-risk exercises when performed incorrectly. The culprit is almost never the movement itself, but the subtle execution errors that accumulate over time.
Fiwa AI's real-time pose detection has analyzed tens of thousands of user squat sessions and identified the 5 most common — and most overlooked — mistakes.
Mistake 1: Knee Valgus (Knees Caving In)
Knees collapsing inward during the descent is the single most common squat error. It disrupts patellar tracking and, over time, leads to cartilage wear and ligament damage.
Why it happens: Weak glute medius and glute maximus, or restricted ankle dorsiflexion.
How to fix it: Consciously "push the floor apart" as you squat, keeping your knees tracking over your toes at all times. Resistance band work around the knees is an excellent drill. Fiwa AI will alert you the moment it detects inward knee drift.
Mistake 2: Heels Rising
Lifting your heels at the bottom of the squat signals limited ankle mobility. This shifts your center of mass forward, increases shear force on the knee, and reduces glute engagement.
How to fix it: Daily calf stretching and ankle mobility work. In the short term, try elevating your heels 1–2 cm with a wedge plate or wearing weightlifting shoes.
Mistake 3: Butt Wink (Posterior Pelvic Tilt)
At the bottom of the squat, the pelvis tucks under and the lumbar spine rounds — known as "butt wink." This places enormous compressive force on the lumbar discs and is a leading cause of lower back injuries.
Why it happens: Limited hip mobility, or squatting deeper than your current range of motion allows.
How to fix it: Start with a parallel squat (thighs parallel to the floor) and gradually increase depth as hip and glute flexibility improves.
Mistake 4: Excessive Forward Lean
A torso that tilts too far forward increases the moment arm between the barbell (or your center of mass) and the hips, dramatically increasing lower back load.
How to fix it: Strengthen your core and erector spinae, and ensure adequate ankle mobility. Cue yourself to "keep your chest up" and maintain a more upright torso throughout the movement.
Mistake 5: Uncontrolled Descent
Many lifters drop into the squat using momentum and bounce out of the hole. This reduces eccentric muscle training benefit and puts significant impact stress on the knee joint.
How to fix it: Control the descent for 2–3 seconds, pause briefly at the bottom, then drive up with intent. Fiwa AI tracks your rep tempo and will flag unusually fast descents.
Real-Time Correction with Fiwa AI
All five of these mistakes are detectable through joint angle analysis. Fiwa AI monitors your form on every single rep and delivers instant audio cues — the equivalent of having a personal trainer watch you from the front and side simultaneously.
Start squatting smarter today. Your knees will thank you for years to come.