Effect of Lead Use on Back and Shoulder Postural Muscle Activity in Healthy Young Adults

Abstract

The primary goal of this study was to test the hypothesis that wearing the 3.7 kg vest portion of a radiological shielding garment (a "lead") significantly increases lower back and shoulder muscle activity in quasistatic erect and forward-flexed postures. Secondarily, the authors examined the effects of gender and forward-flexed posture as well as their interactions with lead use. The use of a lead is mandatory for interventionalists during surgical procedures. Because the vest portion of a lead weighs considerably more than normal clothing, there is concern that its use increases the risk of developing back and shoulder pain. In a repeated-measures study design, 19 young healthy male and female adults assumed standardized erect or forward-flexed postures, both with and without wearing the vest portion of a lead. Shoulder and lower back muscle activity was measured via surface electromyography, normalized by maximum voluntary contraction values. Data were analyzed using general linear models and repeated-measures ANOVA (significant for p < .05). Use of the lead did not result in a significant increase in muscle activity in the lower back or shoulders, despite perceived increases in effort and discomfort. Posture proved to be the most significant secondary factor affecting activity in the lower back, and participant gender proved insignificant. Short-term use of the lead does not appear to contribute to the incidence of back pain or injury in interventionalists. Avoiding flexed postures could more directly reduce the likelihood of pain or injury. Potential applications include assessing and improving operating room ergonomics for physicians.