^ The slo-mo was during that 'world team tennis' thing after he retired, but overall, I don't think his groundies have changed that much. Â Very early in his career, on his BH, he'd sometimes release his left hand after the follow-through (like swinging a bat, I guess), but I didn't notice it that much during his career. Â
His service motion and position changed more, I think... the angle of where he stood on the baseline was different as well as where he leg landed after the follow through. Â He used to land on his right leg in his earlier years, while later one he'd land on his left leg. Â