Table 5.

Rules of the RB classification method to determine the different categories of compensation: Trunk Forward (TF), $Y=0$; Trunk Rotation (TR), $Y=1$; Shoulder Elevation (SE), $Y=2$; Other (O), $Y=3$. For normal movements $Y=4$

Scenario	Rules
Trunk forward (TF)/Trunk backward (O)
S1	$\widehat{Y}=\left\{\begin{array}{cc}0\hfill & \text{if}\mathrm{\Delta }{H}^t>t{h}_{\mathit{TF}}\hfill \\ 3\hfill & \text{if}\mathrm{\Delta }{H}^t<-t{h}_{\mathit{TF}}\hfill \\ 4\hfill & otherwise\hfill \end{array}\right)$
S2 and S3	$\widehat{Y}=\left\{\begin{array}{cc}0\hfill & \text{if}{a}^t\left(p_8^1,p_1^1,p_1^t\right)>t{h}_{\mathit{TF}}\hfill \\ \hfill & \wedge \mathrm{\Delta }{x}^t\left(p_{2/5}^t,p_1^t\right)>0\hfill \\ \hfill \\ 3\hfill & \text{if}{a}^t\left(p_8^1,p_1^1,p_1^t\right)>t{h}_{\mathit{TF}}\hfill \\ \hfill & \wedge \mathrm{\Delta }{x}^t\left(p_{2/5}^t,p_1^t\right)<0\hfill \\ \hfill \\ 4\hfill & \mathit{otherwise}\hfill \end{array}\right)$
Trunk rotation (TR) and Shoulder elevation (SE)
S1	$\widehat{Y}=\left\{\begin{array}{cc}2\hfill & \text{if}(1)a^t(p_{2/5}^1,p_1^1,p_{2/5}^t)>t{h}_{\mathit{SE}}\hfill \\ \hfill & \wedge (2)a^t(p_{5/2}^1,p_1^1,p_{5/2}^t)<t{h}_{\mathit{SE}}\hfill \\ 1\hfill & \text{if}(1)>t{h}_{\mathit{SE}}\hfill \\ \hfill & \wedge (2)>t{h}_{\mathit{SE}}\wedge (1)-(2)\approx 0\hfill \\ \hfill \\ 1\wedge 2\hfill & \text{if}(1)>t{h}_{\mathit{SE}}\hfill \\ \hfill & \wedge (2)>t{h}_{\mathit{SE}}\wedge (1)-(2)\gg 0\hfill \\ \hfill \\ 4\hfill & \text{otherwise}\hfill \end{array}\right)$
Trunk rotation (TR)
S2	$\widehat{Y}=\left\{\begin{array}{cc}1\hfill & \text{if}\mathrm{\Delta }{x}^t(p_{2/5}^t,p_1^t)>t{h}_{\mathit{TR}}\hfill \\ 4\hfill & otherwise\hfill \end{array}\right)$
S3	$\widehat{Y}=\left\{\begin{array}{cc}1\hfill & \text{if}|\mathrm{\Delta }{d}^t(p_2^t,p_5^t)|>t{h}_{\mathit{TR}}\hfill \\ 4\hfill & otherwise\hfill \end{array}\right)$
Shoulder elevation (SE)
S2 and S3	$\widehat{Y}=\left\{\begin{array}{cc}2\hfill & \text{if}\mathrm{\Delta }{y}^t(p_{2/5}^t,p_1^t)>t{h}_{\mathit{SE}}\hfill \\ 4\hfill & otherwise\hfill \end{array}\right)$
Trunk tilt (O)
S1	$\widehat{Y}=\left\{\begin{array}{cc}3\hfill & \text{if}{a}^t(p_8^1,p_1^1,p_1^t)>t{h}_O\hfill \\ 4\hfill & otherwise\hfill \end{array}\right)$
S2 and S3	$\widehat{Y}=\left\{\begin{array}{cc}3\hfill & \text{if}|\mathrm{\Delta }{H}^t|>t{h}_{\mathit{TI}}\hfill \\ 4\hfill & otherwise\hfill \end{array}\right)$