Figure 5

Characterization of frequency spectra. Curves represent group mean values for young (left) and older (right) adults per force level. (a) and (b) Power spectrum for frequencies between 0 and 20 Hz (representing approximately 95% of the total power for each force level). (c) and (d) Proportional power spectrum for frequencies between 0 and 20 Hz. (e) and (f) Log10 power as a function of the log10 frequency for each force level with spectral slopes determined by linear regression (note: for data analysis slopes are calculated based on individuals frequency spectra).