No abstract

The recommendation of a saddle without a narrow protruding nose appears to be justified to reduce pressure to the perineum of the bicyclist.

Exoskeleton devices are being introduced across several industry sectors to augment, amplify, or reinforce the performance of a worker's existing body components-primarily the lower back and the upper extremity. Industrial exoskeletons may play a role in reducing work-related musculoskeletal disorders arising from lifting and handling heavy materials or from supporting heavy tools in overhead work. However, wearing an exoskeleton may pose a number of risks that are currently not well-studied. There are only a few studies about the safety and health implications of wearable exoskeletons and most of those studies involve only a small number of participants. Before the widespread implementation of industrial exoskeletons occurs, there is need for prospective interventional studies to evaluate the safety and health effectiveness of exoskeletons across various industry sectors. Developing a research strategy to fill current safety and health knowledge gaps, understanding the benefits, risks, and barriers to adoption of industrial exoskeletons, determining whether exoskeleton can be considered a type of personal protective equipment, and advancing consensus standards that address exoskeleton safety, should be major interests of both the occupational safety and health research and practice communities. K E Y W O R D S exoskeleton, human augmentation, intervention effectiveness, PPE

This study investigated coordination of the grip force on and force applied with a hand tool using a precision pinch grip. A simulated hand tool was developed to measure grip force exerted on the tool as a function of the force transmitted from the tool to an external object in a dynamic force matching paradigm. Grip force coordination measures reflected subjects' abilities to modulate grip force in parallel with the tool application force and their abilities to minimize excessive grip force. These measures were calculated for seven subjects with a diagnosis of carpal tunnel syndrome (CTS) and seven age- and gender-matched controls. The absolute magnitude of excessive grip force (safety margin) was unreliable because of the high intrasubject variability in coefficient of friction measurements. Linear regression equations predicting coefficient of friction from pinch force magnitude had low r2 coefficients of determination and were generally not statistically significant (p > 0.05). Relative comparisons of grip force control showed that individuals with CTS exhibited a statistically significant (p < 0.05) increase in ratio of grip force to application force (54% higher than controls) and a significant (p < 0.05) decrease in modulation of pinch force with application force (12% lower than controls). These results suggest that individuals with CTS lose some ability to coordinate efficiently grip force on hand tools and exert higher grip forces on tools, at equivalent application forces, than controls. This is believed to be a result of tactile sensibility deficits associated with CTS. As a result, workers with CTS may be at increased risk of accelerating the progression of their musculoskeletal disorder.