The serve does not get faster because the swing gets larger; it gets faster because the kinetic chain fires in sequence. Legs, hips, trunk, arm, then wrist act like linked segments of one whip, passing energy along instead of letting it leak in random directions.
Sports biomechanics frames the serve as a transfer problem, not a strength contest. Ground reaction force from the legs must travel through pelvic rotation, trunk flexion and shoulder external rotation before it shows up as racket-head speed. When that sequence is mistimed, angular momentum dies in the torso or shoulder, no matter how hard the player “muscles” the ball with the arm alone.
Coaches now talk less about “hit harder” and more about joint coupling and timing windows. Video analysis and motion tracking make visible how a compact swing with clean segmental sequencing often produces more ball velocity than an exaggerated windup. For club players, the largest untapped power source is not a bigger backswing, but a more disciplined chain from the ground up.
