Comfort zones, shoulder reach angles, and verification of CDAS

Two experiments were conducted: (1) to test the effects of target location on shoulder reach, and determine comfort zones within shoulder reach; and (2) to verify CDAS (Configuration Design, Analysis, and Simulation -- a computer-aided design software program). Experiment 1 measured the shoulder angles, distance (from shoulder to the target), and the comfort of the reach (using a sevenpoint rating scale) for specified target locations. Twenty, right-handed subjects (ten male and ten female) ranging between the 5th percentile and the 95th percentile for both sexes were tested. The results indicate that target location had a significant effect on angle, distance and comfort. Comfort zones were determined and compared to those previously reported by Rebiffe, Zayana and Tarriere (1969). Experiment 2 simulated Experiment 1 on the computer. Man-models were built to the subjects' dimensions, and manipulated to perform the specified reaches, as in Experiment 1. The results from Experiment 2 were compared to those from Experiment 1. The results reflect a moderate correlation for angle, although the comfort scores showed little to no correlation. Limitations in the CDAS system are identified as possible explanations for the weak correlation.