Figure 3.

Graphical representation of Q and R parameters and the equations used to calculate these parameters. Uf represents the total distance the skin stretches after completion of the suction period. Ua represents the total distance the skin retracts back to its normal position at the end of the relaxation period. Ue is the distance skin stretches in the initial 0.1 s of suction. Uv represents the distance the skin stretches between the first 0.1 s and the end of the suction phase. Ur is the distance the skin retracts in the first 0.1 s of the relaxation phase.