Research of cyclist’s spine dynamical model

Abstract

The purpose of the paper is to present a dynamic model of bicycl ist’s lumbar spine for the evaluation of linear and angular var iation of intervertebral distance in sagittal plane. Ten degrees of freedom biomechanical model of the spine was solved numerically. Larger loads acting on a cyclist spine occur mostly while sitting in a sport position in comparison with recreation or middle sitting. The load on lumbar spine region is influenced by cycle’s tire pressure, ro ad bumps and wheeling speed. The bi ggest linear and angular displ acements were found between L4–L5 vertebras. The biggest load protractil e spine muscle experiences in th e sport sitting position. Maximu m vertebrae rotation and linear variation values in wheeling regime with 1.5 Bar tyres pressure and at a speed of 10 km/h are 0.4 6 ° and 0.46 mm. Maximum vertebrae rotation and linear variation values for a 23 year old, 1.74 m high and 73 kg of mass (bicycle mass ~7 kg) man in wheeling regime with 3.5 Bar tyres pre ssure and at a speed of 30 km/h are 3.9° and 1.23 mm. The biggest variation of rotation in sagittal plane between two neares t lumbar spines is about 1°. Because of this displacement the frontal part of last mentioned disc is compressed with 530 N more and dorsal disc part as much less.