Figure 2.
Normal forces (Fn) of the thumb (TH) and vitual finger (VF) exerted on the handle under different load conditions (0.1, 0.2, and 0.3 kg) and different lever arms (black bars: 0.08 m; white bars: 0.16 m; gray bars: 0.24 m). The averaged data across trials and subjects are presented with standard error bars. Both VF and thumb normal forces scaled with the load and lever arm.