Fig. 9. Correlation between downstroke deviation and force inclination. (Ai) Time course of force inclination during the downstroke for a single individual, color-coded according to downstroke deviation. The slope and R² regression statistics for the correlation between downstroke deviation and force inclination are shown for normalized time intervals of 0.05. Regression statistics are shown for the individual (black circles) and the population (gray circles). The vertical dotted line indicates a normalized time of 0.65. (Aii) Correlation between downstroke deviation and the mid-downstroke (normalized time 0.65) force inclination for the experimental population (R²=0.71). Black circles indicate data for the individual in Ai. (Bi) Time course of force inclination during the upstroke for a single individual, color-coded according to downstroke deviation. The slope and R² regression statistics for the correlation between downstroke deviation and force inclination are shown at the bottom, as in Ai. The vertical dotted line indicates a normalized time of 0.55. (Bii) Correlation between downstroke deviation and mid-upstroke (normalized time 0.55) force inclination for the experimental population (R²=0.03). Black circles indicate data for the individual in Bi.