HOW IT'S DONE General Electric's motion-detection camera generates a 3-D image of Furyk's swing in motion, capturing video and invisible near-infrared light. Computer software then takes that image and builds a musculature avatar. The avatar is rendered from GE's Healthcare-imaging technology.Comments from Golf Digest fitness advisor Ralph Simpson, certified manual physical therapist and former fitness trainer on the PGA Tour.

ADDRESS Jim Furyk's muscle activity is fairly quiet except for his lower leg muscles, which are balancing his body.

HALFWAY BACK His right gluteal, quadriceps and hamstring muscles are loading.His erector spinae and abdomen muscles also are engaged.

His right gluteal, quadriceps and hamstring muscles are loading. His erector spinae and abdomen muscles also are engaged.

THE TOP Several muscles fire to stabilize his body in this torqued position, including scapular stabilizers, rotator cuffs, trunk extensors, and his right hamstrings.

HALFWAY DOWN Jim's right pectoral muscle fires to bring the club down. The left latissimus dorsi and hip adductors are pulling his body through its rotation while his right glute is pushing it. His quadriceps are trying to stabilize his legs because of excessive knee motion.

IMPACT His forearm, chest and rotator-cuff muscles are really contracting to brace for the hit. His hamstrings, quadriceps, glutes and abdomen muscles all fire vigorously.

FOLLOW-THROUGH Jim's trunk muscles are allowing his body to rotate left without too much side bend, while his quads and hamstrings work to stabilize his hips and knees.