Musculoskeletal biomechanics of human rolling

Abstract

Rolling in the bed is an essential and complex activity of daily living. A reduction in rolling variability may reduce the complexity and aid our understanding of human rolling. The goal of this study was to find the mechanical energy requirements for rolling and calculate the musculature demands associated with rolling under two conditions: 1) arms crossed over the chest and 2) arms uncrossed and free to move naturally. The objectives of this study were investigated in two chapters. The objectives of the first chapter were to calculate and compare the mechanical energy requirements for both whole body and individual body segments under the two rolling conditions. Kinematic data were recorded from healthy adults and analyzed to calculate the mechanical energy generated for each rolling condition. The mechanical energy for arms crossed was 60.1 +/- 12.1J and for arms uncrossed was 72.6 +/- 13.8J respectively. The statistical analysis indicated that there was a significant difference between two rolling conditions and the arms were the primary contributor for the observed energy differences. The objectives of the second chapter were to determine and compare the muscle work generated by the whole-body and individual segments for each rolling condition. Kinematic and ground reaction force data were recorded and used to generate rolling simulations and calculate muscle work measures. The muscle work averaged across subjects for rolling with the arms crossed and uncrossed was 538.3 +/- 195.1J and 569.9 +/- 105.7J respectively. The statistical analysis indicated that there was no significant difference in overall muscle work between the two rolling conditions. In contrast, there was a significant difference in shoulder muscle work between rolling conditions.