ATTENUATION OF GROUND REACTION FORCES IN DISMOUNTS FROM TEH BALANCE BEAM

Abstract

Epidemiological studies have documented the incidence of injuries in female gymnasts . In comparison to other sports, the incidence of injury in gymnastics is high relative to other sports. One epidemiology study prompted the author to state that "...women's gymnastics should he recognized as a hazardous sport." To understand the etiology 01 injury, researchers have identified injuries by sites, types and/or events (floor, uneven bars, vault, and balance beam). Dismounts, considered an element 01 all events, have drawn attention as an injury mechanism. Studies have shown he dismount, especially when gymnasts attempt to "stick" their lauding, to be a major component of the incidence of injury. This study investigated ground reaction forces in the dismount from the balance beam under two styles (stick and roll-out of the landing). Attenuation of relatively high impact forces through modification of landing may be used, at minimum, in practices to reduce the exposure to gymnasts to this physical contraindication. Subjects were 23 female gymnasts who ranged in age (118 to 201 months, mean=158.8, SD=23.7) and level (5 to 10). Each subject was asked to perform two types of dismounts (roundoff and barani) from a balance beam and to land each dismount with two the different styles onto a mot adhered to a force platform. AU subjects had ground reaction forces for both styles of the roundoff. and 14 subjects had ground reaction forces for both styles of the barani dismount. Table 1 contains a summary of the ground reaction forces as a percentage of body weight. Our results indicate that vertical ground reaction forces are significantly reduced by rolling out of the landing.