The Titleist Performance Institute has spent decades studying the relationship between body function and golf swing mechanics. Their research produced a clear framework: when the body cannot perform a movement the swing requires, it compensates. Those compensations are what your instructor sees as swing faults.
No amount of technical instruction changes a physical limitation. What changes it is training — specifically the right sequence of stability work, mobility work, strength, and power development applied to the right joints. Below is a breakdown of the four faults we see most often, what physically causes them, and how we train the correction.
Early extension is the most common swing fault TPI screens for — and it is almost always driven by a lack of internal rotation of the lead hip. When the left hip (for a right-handed golfer) cannot rotate inward through impact, the pelvis has no choice but to move toward the target instead of rotating around it.
Hip mobility restrictions are often combined with limited ankle dorsiflexion, which contributes to a compensatory hip thrust rather than a hip turn. Poor glute activation also plays a role: without strong glutes anchoring the pelvis, stability through the backswing is compromised.
The Kinetix program targets hip internal rotation through specific mobility work on Move days and builds the glute strength required to stabilize through impact on Heavy and Control days. By Week 3 of Kinetix6, most golfers report a noticeable change in how their hips feel at impact — not because we changed their swing, but because we changed what their body can do.
Train the fix with Kinetix6 →Over the top is one of the most frequently taught swing faults — and one of the most misunderstood. Most instruction focuses on the arm path, but the root cause is almost always limited thoracic spine rotation. When the upper back cannot rotate adequately, the body cannot create the shoulder depth at the top of the backswing that an on-plane downswing requires.
Without adequate T-spine rotation, the arms must compensate during the downswing — and the path of least resistance to the ball is over and across the line. This is the body solving a mobility deficit the only way available to it. Technical drills address the symptom; training addresses the cause.
Move days in every Kinetix program prioritize thoracic spine mobility because it unlocks every rotational pattern in the swing. As T-spine rotation improves, golfers naturally find more depth in the backswing and an inside approach path on the downswing — without changing anything about their swing consciously.
Train the fix with Kinetix6 →The hip slide typically originates from a combination of weak lateral hip stabilizers and poor single-leg balance. When the glute medius and hip abductors cannot stabilize the pelvis over the lead leg, the body defaults to a lateral shift rather than a rotational pattern.
S-posture (anterior pelvic tilt at address) is a related pattern often driven by tight hip flexors and inhibited glutes. This setup posture pre-loads the lumbar spine and makes it physically difficult to maintain a stable base through the swing. Single-leg strength work and anti-lateral-shift core training are the direct fix.
Train the fix →Loss of posture is a core endurance problem as much as a flexibility problem. The golf swing applies significant rotational and extension forces to the spine — forces that require the core musculature to resist. When core endurance is inadequate, posture breaks down under those forces regardless of what the golfer knows technically.
Loss of posture is also related to hip flexibility. The address position requires a hip hinge — forward spine lean maintained by the posterior chain. If the hamstrings and glutes cannot maintain that position under load across 18 holes, posture degrades across the round. This is why many golfers hit well on the range but lose it by the back nine.
Train the fix with Kinetix6 →The Kinetix6 program is built specifically to address all four fault categories through a progressive 6-week sequence. Starts tomorrow. Direct coach access throughout.