Physiological responses to weight lifting in different planes

A weight of 10 kg was lifted by 11 normal male volunteers (mean age 34·2 years) from ground to knee, hip, and shoulder levels in the sagittal, lateral and oblique planes. During these lifting manoeuvres intra-abdominal pressure was measured by telemetry and the activity of erector spinae and external oblique were recorded by electromyography. The values obtained for peak and sustained intra-abdominal pressure and the averaged electromyographic activities of erectores spinae and external obliques were subjected to analysis of variance and correlation analysis. A significant difference between the responses in these three planes was found: the sagittal plane activities evoke least response. Intra-abdominal pressures, erector spinae activity and external oblique activity were highly significantly correlated in each of the three planes.