Orthopedics This Week | December 5, 2017 | Page 8

ORTHOPEDICS THIS WEEK VOLUME 13, ISSUE 38 | DECEMBER 5, 2017 According to Jones, “A 10m platform diver can reach up to velocity of 16.4 m·s -1 (36 mph) before entering the water with quick deceleration to 33 km·h -1 (20 mph) on impact with water, with a force of about 400 kg·N - 1 . Thus, the impact at the water sur- face on the diver can reach 2.0 g to 2.4 g. A 1-m springboard dive reach- es an average peak velocity of 8.4 m·s -1 (30.1 km·h -1 or 19 mph). Upon water impact velocity is decreased by greater than 50% within a fraction of a second.” He wrote that “these incredible veloci- ties and impact forces are thought to be large contributors to competitive diving injuries” and that “with such forces, injuries can occur not only in the setting of a dive gone wrong, but also more commonly secondary to an accumulation of exposures to repeti- tive forces.” “These principles of the physics of div- ing,” he said, “are vital to understanding the nature and cause of many of com- petitive diving injuries.” The Diving Mechanics and Result- ing Musculoskeletal Injuries Competitive divers train about 40 hours a week. Springboard divers aver- age usually 100 to 150 dives a day while platform divers average about 50 to 100 dives per day. Between the impact forces on the body and the constant repetition of movement, injury can happen in any of the phases of the dive. The first phase of the dive of course is the take-off from the diving plat- form which includes the approach, hurdle (where the diver jumps on to the end of the board) and the press (the depression of board and the upward acceleration of the diver’s 8 body). If the timing of downward motion of the board with the down- ward motion of the diver onto the board is not perfect, the diver is at high risk of lower-extremity injuries, especially of the knee. Most common lower extremity inju- ries, according to Jones, are patellar tendinopathy, quadriceps tendinopa- thy and patellofemoral compression syndrome. The combination of over- training on the board and on dry land can also lead to Achilles and posterior tibialis tendinopathy. If an athlete per- forms an arm stand dive off the plat- form, then they are also at risk for upper-extremity injuries. The second phase is the flight or midair maneuver which begins as soon as the diver leaves the board and ends when he or she hits the water. The common injuries during this phase are spine Advertisement ryortho.com | 1-888-352-1952