Biomechanics of the spine in the polevaulter as related to spondylolysis

Abstract

An athlete was filmed at high speed to anatomically plot the position of the vertebrae during several pole vaults. A computer analysis adapted from a previously described program (Gainor, BJ, et al: The kick: Biomechanics and collision injury. Am J Sports Med 6: 185-193, 1978) was used to quantify the kinematic data. The thoracic and lumbar vertebrae of the polevaulter began in a neutral position but rapidly hyperextended 40 degrees during pole plant. The spine subsequently flexed 130 degrees in 0.65 seconds as the pole uncoiled and the athlete was propelled towards the bar. Angular velocities of the spine reached a maximum of 6 radians/sec during both extension and flexion. More significantly, angular accelerations of 150 radians/sec2 occurred in hyperextension, and 180 radians/sec2 in hyperflexion. Torque about the spine was estimated to be 1,500 inch-pounds during extension and 1,800 inch-pounds during flexion. The maximum kinetic energy in the athlete's body was calculated to be 36,000 inch-pounds. We believe the magnitude of these torques and accelerations predispose the back to injury. These results were correlated with several cases of spondylolysis in competing polevaulters.

Biomechanical Pole Vault Patterns Were Associated With a Higher Proportion of Injuries

“…Indeed, a more horizontal pole reaction force opposed to the athlete may increase the energy dissipated (as heat) within the hyperextended vaulter's body (Linthorne, 2000), and may elongate tissue above their own elastic capabilities. Gainor et al (1983) found that such mechanisms could be related to back injuries. Back injuries were not one of the main reported injuries in our present studies (only 4 athletes reported having had back injuries during the 12 preceding months, therefore this injury had not been reported as an outcome).…”

Mechanics of pole vaulting: a review

“…At take-off, the vaulter has high horizontal velocity and a great elevation of the dominant arm, and begins to resist the load from the pole. This combination of factors is such that the vaulter is subjected to high loads that may lead to injuries like rotator cuff tendonitis, shoulder instability, low back pain or spondylolysis (Gainor et al, 1983;Beattie, 1992;Bird et al, 1997;Brukner et al, 2004) when the take-off is not executed with accuracy. Accuracy refers to the placement of the last support relative to the upper hand.…”

Catastrophic Injuries in Pole-Vaulters

“…Although several articles have been published on the biomechanics and physics of pole vaulting, there are only a few clinical studies in the English literature. 1,6 We are aware of only one death that was reported in a pole-vaulter who was impaled. 7 In one report the biomechanical action of the spine was analyzed and correlated to the development of spondylolysis in three pole-vaulters.…”

“…There are few epidemiologic studies of pole-vault injuries, and those that do exist have paid more attention to less severe injuries, such as sprains, strains, and extremity fractures. 1,6 We report on 32 catastrophic pole-vault injuries that were recorded by the National Center for Catastrophic Sports Injury Research between 1982 and 1998. The purpose of this article is to examine the details of these catastrophic pole-vault injuries by reviewing patient demographics, mechanisms of injury, levels of experience, equipment, diagnosis, and outcome.…”