Thoracic hyperkyphosis and its improvement in high-school baseball players

Abstract

Hyperkyphosis is one of the risk factors for medial elbow injuries in baseball players. The purpose of this study was to determine the prevalence of hyperkyphosis in high school baseball players (Experiment 1) and to investigate the acute effects of spine mat usage in improving hyperkyphosis in high school baseball players (Experiment 2). Experiment 1: A study of 142 high school baseball players was conducted. A Spinal Mouse® was used to measure the thoracic kyphosis angle (TKA) with participants in an upright position. Hyperkyphosis was defined as a TKA of >40° in this study. The results showed that the prevalence of hyperkyphosis was 20.4% (29/142). Experiment 2: The participants were 56 high-school baseball players. For the intervention, the participant was placed in a supine position on a bed, and a spine mat was inserted such that it adhered to the thoracic spine. The primary outcome variable was TKA measured in the upright position using a spinal mouse before and after intervention with a spine mat. Based on this evaluation, we assigned the participants to two groups: hyperkyphotic (n =18) and non-hyperkyphotic (n=38). There were significant differences in pre- and post-test TKA in both groups (hyperkyphotic group: pre-test 44.4±3.8°, post-test 39.9±4.6°, P < 0.01; non-hyperkyphotic: pre-test 31.8±5.7°, post-test 29.2±7.8°, P < 0.01). The results of this study indicate a high prevalence of hyperkyphosis in high school baseball players. In addition, using a spine mat may lead to an acute improvement in hyperkyphosis in high school baseball players.