STUDY DESIGN: Control laboratory study consisting of preintervention and postintervention measurements. OBJECTIVE: To determine the effects of a putting practice session on the kinematics of full golf swings made by skilled male golfers. BACKGROUND: Skilled golfers perform putting practice for prolonged periods. The combination of sustained trunk flexion with minimal trunk motion may affect the endurance capacity of the trunk extensor muscles. Because of their important role in the golf swing, any impairment of the trunk extensors may negatively influence full-swing kinematics, but this has not been previously evaluated. METHODS AND MEASURES: Three-dimensional swing kinematics and holding time on the Biering-S貥nsen test of isometric trunk extensor endurance were evaluated in 29 skilled male golfers before and after performing a 40-minute putting task. RESULTS: After the intervention, peak segmental speeds were reduced and total swing duration increased (mean ᠓D, 36 ᠵ5 milliseconds). There were reductions in the magnitude of pelvis and torso axial rotation during the downswing (mean ᠓D, -2.3࠱ 2.6ࠡnd -2.3࠱ 4.7ଠrespectively). The peak difference between torso rotation and pelvis rotation during early downswing was also significantly reduced by 0.9࠱ 2.0ࠨP<.05). The effects on pelvis and torso rotation were smallest for golfers with higher body mass index (BMI). Holding time on the Biering-S貥nsen test after putting practice was significantly reduced by 25.7 ᠲ3.8 seconds (P = .01). CONCLUSION: Changes in swing kinematics observed following 40 minutes of putting practice might have resulted from fatigue-related impairment of the trunk extensor muscles, a view supported by the poorer performance on the postintervention Biering-S貥nsen test. Results showed that swing kinematics of golfers with high BMI were least affected by the putting practice. LEVEL OF EVIDENCE: Harm, level 5.