Interventions Based on the pilot data, the investigators have selected 2 tool handle designs that are similar to conventional tools but have features that exploit the differences identified in our preliminary data. The dependent measures of pinch force and muscle activity were most sensitive to diameter, followed by weight, followed by shape. The tool characteristics selected for this proposal are based on the data from the laboratory studies presented in the Preliminary Studies section and the Appendix (Dong et al., JADA, 2006; Dong et al., Appl Ergo, 2007). The tool parameters were selected to provide the greatest difference in peak pinch force, yet be as close as possible to the look and feel of a conventional instrument. Half of the participants will be provided with Tool 1 and half with Tool 2. Tool 1 is the closest to a conventional tool in diameter and weight while Tool 2 has a larger diameter and is lighter. The differences and similarities between Tools 1 and 2 are listed below.