Figure 4. Displacement loops: Fz– (Right top), Fx– (Right bottom), Velocity–(Left top) and Power– (Left bottom) Displacement loops, in Pre (Black solid line), Post 1 (Solid grey line) and Post 2 (Dotted grey line), respectively. t_ECC: eccentric contact phase, t_CON: concentric contact phase. The time intervals of significant Pre – Post 1 (a) and Pre – Post 2 (b) piecewise loop area differences, due to multiple crossings in Fz– and Power–Displacement loops (p ≤ 0.05) are noted.