Does decrease of the thoracic kyphosis influence decrease knee adduction moment during gait? A preliminary study of a healthy population

[Purpose] The purpose of this study was to investigate the influence of a decrease in thoracic kyphosis angle on the knee adduction moment during gait in healthy young individuals. [Subjects and Methods] Twenty-nine healthy adults, consisting of 15 males and 14 females (21.6 ± 1.1 years old), participated. The draw-in maneuver was used to decrease thoracic kyphosis, and thoracic kyphosis was measured using a SpinalMouse during normal standing and standing with the draw-in maneuver. The participants were required to maintain the draw-in maneuver during gait. A 3-D motion analysis system and a force plate were used to obtain knee adduction moment. [Results] Thoracic kyphosis angles during the draw-in maneuver (41.0 ± 7.4 degrees) were significantly decreased compared with the angles during normal standing (43.0 ± 7.9 degrees). Although the knee adduction moment during gait with the draw-in maneuver was not significantly decreased compared with that during level gait, in the 20 subjects who had decreased kyphosis due to the draw-in maneuver, the 1st peak knee adduction moment (55.7 ± 24.3 × 10(−3)) with the draw-in maneuver was significantly decreased compared with the knee adduction moment (57.0 ± 16.3 × 10(−3)) during level gait. [Conclusion] Knee adduction moment in the case of a decreased thoracic kyphosis angle due to the draw-in maneuver was decreased compared with that during level gait.