Technique and ground reaction forces in the back handspring.

The ground reaction forces at the hand that produced compression forces and varus/valgus moments at the elbow joint during the double-arm support phase of the back handspring were studied. The relationship of technique, namely elbow joint flexion, to these forces were also studied. Compression forces and forces producing valgus moments have been implicated in overuse injuries to the elbow joint. Video and force plate analysis of six young female gymnasts showed that 1) the elbow joint flexed during the double-arm support phase, and 2) the reaction forces at the hand produced large compression forces (an average of 2.37 times body weight) and sizable valgus moments at the elbow (an average of 0.03 times body weight times body height). The combination of these forces may contribute to the occurrence of lateral compression injuries of the elbow joint (e.g., osteochondritis dissecans of the capitellum). Correlations of measures of elbow angle and measures of reaction force showed that large elbow flexions may protect the elbow from large valgus moments.