# Muscle Activity of Superimposed Vibration in Suspended Kneeling Rollout
## 3 Results  
A fixed effect of the exercise condition was found on the pectoralis sternalis [F\({}_{(2,32)}\) = 3.757, \(p\) = 0.034], anterior deltoid [F\({}_{(2,32)}\) = 7.833, \(p\) = 0.002], latissimus dorsi [F\({}_{(2,32)}\) = 16.017, \(p\) < 0.001], infraspinatus [F\({}_{(2,32)}\) = 8.404, \(p\) = 0.001], and global activity [F\({}_{(2,24)}\) = 12.794, \(p\) < 0.001], but not for the pectoralis clavicularis [F\({}_{(2,32)}\) = 2.89, \(p\) < 0.07] or serratus anterior [F\({}_{(2,32)}\) = 2.35, \(p\) < 0.112]. The pairwise comparison, in Table 1, showed that in the suspended kneeling rollout, the effects of superimposed vibration at 25 Hz were significantly higher than those of the non-vibration condition with a small effect for the anterior deltoid (\(p\) = 0.004, \(d\) = 0.29, CI: \(-\)0.30; 0.87), a large effect for the latissimus dorsi (\(p\) < 0.001, \(d\) = 0.90, CI: 0.29; 1.51), and a medium effect for the infraspinatus (\(p\) = 0.001, \(d\) = 0.62, CI: 0.03; 1.22) and the global activity (\(p\) < 0.001, \(d\) = 0.71, CI: 0.11; 1.30). The superimposed vibration on the suspension straps at 40 Hz showed a significant small effect compared to the non-vibration condition for the pectoralis sternalis (\(p\) = 0.021, \(d\) = 0.30, CI: \(-\)0.29; 0.88), anterior deltoid (\(p\) = 0.005,\(d\) = 0.41, CI: \(-\)0.18; 0.99), and infraspinatus (\(p\) = 0.027, \(d\) = 0.46, CI: \(-\)0.13; 1.05). Likewise, a significant medium effect for the latissimus dorsi (\(p\) < 0.001, \(d\) = 0.69, CI: 0.10; 1.29) and global activity (\(p\) < 0.001, \(d\) = 0.68, CI: 0.08; 1.28) was found under superimposed vibration at 40 Hz compared to the non-vibration condition. The graphical representation of Cohen's d can be found in Figures 3-5. The [PERSON] test showed a main effect of exercise condition on the OMNI-Res [X\({}^{2}\)(12) = 11.451, \(p\) = 0.003]. The post hoc Conover pairwise comparison in Figure 6 shows that the perception of effort was significantly higher for the suspended kneeling rollout with vibration frequency at 40 Hz (4.6 \(\pm\) 1.3, \(p\) = 0.001, \(d\) = \(-\)0.46, CI: \(-\)0.69; \(-\)0.13) than for the non-vibration condition (3.4 \(\pm\) 1.6). Moreover, non-significant differences were found under the vibration \begin{table}
\begin{tabular}{l c c c} \hline \hline \multirow{2}{*}{**Muscle Group**} & \multicolumn{3}{c}{**Suspended Kneeling Rollout**} \\ \cline{2-4}  & **Non-Vibration** & **Vibration at 25 Hz** & **Vibration at 40 Hz** \\  & **Mean \(\pm\) SD** & **Mean \(\pm\) SD** & **Mean \(\pm\) SD** \\ \hline Pectoralis clavicularis & 23.5 \(\pm\) 16.6 & 30.3 \(\pm\) 20.2 & 30.1 \(\pm\) 18.9 \\ Pectoralis sternalis & 25.5 \(\pm\) 14.7 & 27.4 \(\pm\) 17.7 & 30.7 \(\pm\) 19.7 a \\ Anterior deltoid & 3.3 \(\pm\) 2.6 & 4.2 \(\pm\) 3.8 a & 4.8 \(\pm\) 4.5 a \\ Serratus anterior & 24.9 \(\pm\) 13.2 & 26.7 \(\pm\) 16.6 & 28.5 \(\pm\) 17.2 \\ Latissimus dorsi & 20.7 \(\pm\) 10.1 & 31.2 \(\pm\) 13.0 a & 28.5 \(\pm\) 12.3 a \\ Infraspinatus & 26.0 \(\pm\) 11.3 & 34.3 \(\pm\) 15.1 a & 32.5 \(\pm\) 16.8 a \\ Global activity & 20.6 \(\pm\) 6.5 & 25.7 \(\pm\) 7.7 a & 25.9 \(\pm\) 8.6 a \\ \hline \hline \end{tabular} SD: standard deviation;a significantly different compared to non-vibration.  
\end{table} 
Table 1: The sEMG activity for each analysed muscle in suspended kneeling rollout. Data are expressed as a % MVIC. Figure 3: Acute effects on sEMG activity of superimposed vibration at 25 Hz and non-vibration in the suspended kneeling rollout. The lines represent the 90% confidence interval (CI) for the effect of superimposed vibration at 25 Hz on the suspended kneeling rollout. Dotted lines represent the smallest threshold. frequency at 25 Hz condition (4.2 \(\pm\) 1.7) compared to other conditions. Figure 6 shows the OMNI-Res for each suspended kneeling rollout condition represented as a boxplot. Figure 4: Acute effects on sEMG activity of superimposed vibration at 40 Hz and non-vibration in the suspended kneeling rollout.