Three-dimensional kinematics and trunk muscle myoelectric activity in the elderly spine – a database compared to young people

Objective. To establish a database of lumbar spine kinematics and muscle activation profiles for a healthy elderly population. Design. Spine motion parameters and muscle activation profiles of the elderly were identified and quantified in part by comparison with an existing database of younger people. Background. Databases are often used as a benchmark to establish what is “normal”, or for developing appropriate exercise programs or diagnostic methodologies. Methods. Twelve people (average age 69 yr) performed full range of motion movements about the flexion, lateral bending and axial twist axes of the lumbar spine. Fourteen torso muscles (7 per side) were monitored with electromyographic electrodes and the signals normalized to maximum voluntary efforts. Results. The elderly were slower moving, and had a reduced range of motion in full flexion and lateral bend but not in axial twist. Furthermore there was more coupled motion evident in the twisting efforts of the elderly. Abdominal muscles appeared to become more active, earlier in the lateral bending movement. Conclusions. Loss of motion is normal with age together with subtle changes in the way the spine moves and groups of muscles are recruited around the torso.