The Biomechanical Effect of Backpack COM Location during Outdoor Obstacle Crossing

• Main Authors: Yung-Hsing Chiu, 邱永興
• Other Authors: Wu-Chou Chen
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/94226563258211835474

博士 === 國立體育大學 === 體育研究所 === 103 === The ability of load carriage walking over varying terrain during hiking or mountain climbing is common and vital. The backpack packing is important before starting the activity. The purpose of this study was to investigate the effects of different backpack load placements on biomechanical gait parameters. Sixteen healthy male adults (age: 25.5 ± 5.4 yrs; BW: 70.3 ± 7.8 kg; BH: 1.73 ± 0.04 m) were recruited to carry a backpack loaded with 4 different COM placements (unloaded, 1st thoracic vertebra, 7th thoracic vertebra, 1st lumbar vertebra) to step over obstacle under 3 different height conditions (20 %LL, 30 %LL, 40 %LL) separately. The kinematic and GRF data were collected by the Vicon624 T40 motion analysis system and 2 Kistler forceplates synchronously. Dependent measures were analyzed with two-way repeated MANOVA. The results were as following: 1.For comparisons of ROM of systematic center of mass, no significant differences were found between backpack COM placements, but an overall trend with smaller value for 1st thoracic vertebra location. 2.The maximal right COM-COP inclination angles of 1st and 7th thoracic vertebra location were smaller than unloaded condition. In addition, the maximal left inclination angles for all loaded conditions were lager than unloaded condition. However, there was a significant smaller maximal posterior angle while loading carriage compared with unloaded condition. 3.In early stance phase, there were significant larger peak joint moments of trailing leg for knee flexion moment, hip and knee adduction moment on loading carriage than unloaded condition. In late stance phase, there were significant larger peak values for hip flexion moment, ankle dorsi-flexion moment, hip & knee adduction moment, and ankle internal rotation moment on loading carriage than unloaded condition, and 1st lumbar vertebra location was significant greater than 1st thoracic vertebra location for ankle dorsi-flexion moment and knee adduction moment. These findings suggested that setting backpack COM location at 1st thoracic vertebra level can save more energy demand and exert lower injury risk during obstacle crossing. While packing setting with 7th thoracic vertebra level during obstacle crossing, it produces preferable gait stability. From the viewpoint of injury prevention, the 1st lumbar vertebra level is the most unsuitable location. When hiking outdoors, hikers should adjust their backpack COM displacement according to their specific demand of environment and route condition to reach the best body motion pattern.