Reproducibility of surface electromyogram and intra-abdominal pressure for use in ambulatory monitoring.

Abstract

Measurements of intra-abdominal pressure and the surface electromyogram of back muscles have been used extensively to quantify and assess posture and spinal loading in both the laboratory and at the workplace, but only recently has equipment become available to monitor these responses within the framework of a continuous and remote strategy. This paper investigates the reproducibility of these measures within this framework and discusses the analysis of data obtained Findings show reproducibility of recorded data from a task-induced activity to be 80% within one individual's response sequence, and differences between individuals are reproducible up to 60%. The inter-individual variation amounts to approximately 15% of the total variation of the response. Sampling plans for workplace studies are derived for which differences in response between tasks within a job, between jobs and between different groups of workers can be detected within the 95% confidence regions.