It began with his right leg lifting from the pavement, and the right knee rapidly flexing and then extending. As soon as his foot slammed down and planted itself on the macadam, Jack twisted his torso to the left to go around Spit, who was still recovering from the head fake and the cross-dribble. With Jack's left foot now off the pavement, his entire weight was transferred to his partially flexed right knee, which also had to deal with the sudden counterclockwise torsion.

If Jack had stopped to calculate the forces acting on his fifty-two-year-old knee, he might have thought twice about what he was asking his heretofore-faithful anatomy to withstand. Although his lateral ligaments held, since they effectively distributed the forces along their comparatively sizable width, the situation was different for the anterior cruciate ligament, which had lengthened slightly over the years as Jack had aged. Vainly, the relatively narrow band of tissue, which most people referred to as gristle when encountered in a leg of lamb but which Jack knew as collagen, tried to keep the femur from dislocating backward from the tibia. Unfortunately, the involved forces overwhelmed the ligament, and with a popping sound, it literally ripped apart and briefly allowed Jack's femur to dislocate out of its socket, tearing the delicate leading edges of both menisci in the process.

Jack's right leg crumbled, hurling him onto the rough-surfaced pavement, where he skidded forward a few feet, leaving a significant amount of skin behind. One instant he was a coordinated mass of goal-directed muscle and bone, the next a bruised and abraded heap prostrate on the ground, wincing in pain while clutching his knee. Jack wasn't one hundred percent certain of what had happened, but he had an idea. All he could do was hope he was wrong.

"Man, you're going from bad to worse," Warren said after he'd sprinted over and assured himself that Jack was basically okay. Warren's tone reflected half sympathy, half disgust. He straightened up and thrust his hands on his hips, glaring down at his injured friend. "Maybe you're getting too old for this, doc, you know what I'm saying?"