## 3 Results  
Initially, the process of screening the electronic database yielded 11739 papers. Screening of the titles and abstracts eliminated 11728 articles. The agreement was reached for 11 papers that were related to the purpose of this review. Further analysis of the study excluded another three full-text records due to the inability to obtain specific numerical data. A total of eight articles were selected for the review process (Figure 1). The following items were selected from the eight papers that were included in this review: characteristics of the people who participated in the study, the purpose of the study, and the tasks participants had to perform. The other features were a description of the equipment, perturbation locations, and the study results (Table 2). The papers were arranged in order from oldest [19] to newest [20]. Figure 1: Flowchart demonstrating the selection of articles through the review process. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Study and Quality** & **Study Group: Age (Years)**; & **Equipment/Perturbation Source/Place of** & **Body Mass (Spi)** & **Aim/Partipant Task** & **Impact/Essential Description/Start of the Measurement** \\ \hline [PERSON] et al. (1999) & Young (Y: 13 W) & Aim: to investigate whether the & Kinematics-Optotrak System (200 Hz). \\ (1999) [19] & Age \(20.9\pm 2.5\) & performance on an involuntary step & \\ Quality: & Weight \(\epsilon\) = 5.4 & task was comparable to the & Two force plates measured the GRF from both legs (2000 Hz). \\
13/19 & Height: 170.3 \(\pm\) 6.9 & performance on a voluntary step & (2000 Hz). \\  & Elderly (E) : 11 W & lack. & EMG bilateral (2000 Hz) TA. \\  & Age \(68\pm 41\) & Subjects agreed as fast as possible & equally fast in foot lifting (Y: 323 \(\pm\) 59 ms; \\ Weight: \(69\pm 146\) & & the direction of a minimally & Pulling/Pelvis. \\ Height: \(165.8\pm 6.8\) & destabilizing lateral waist pull (voluntary step task), or the & Safety harness. The second harness around the \\  & responded naturally to a large & destabilizing lateral waist pull & were produced using electronically released weight and cable systems. \\  & & The waist pull distances were 8.7\% and 1.3\% of the \\  & & & \\  & & & \\  & & & \\  & & & \\  & & & \\  & & & \\  & & & \\ \hline [PERSON] et al. & 10 M & Aim: to provide insights into the & 42 infrared emitting diodes (IREDs) were placed on \\ (1999) [15] & Age \(26\pm 4.2\) & underlying motor mechanisms used & the participant three IREDs (40 Hz) were placed on \\ Quality: & Weight: \(86\pm 8.2\) & in postural control by determining & the perturbation device; uni-axial force transducer. \\
13/19 & Height: \(181.6\pm 7.1\) & the joint moments during balance & (2) The direction of trunk movement was \\  & & recovery from MLP, perturbations. & Two force plates (480 Hz). \\  & & Participants were instructed that & \\  & & they would be receiving pushes to & \\  & & the trunk or pelvis, and that they & The impulse of ML perturbation: \\  & & should attempt to maintain balance & Shoulder: 13.1 to 28.9 Ns; \\  & & & \\  & & & \\  & & & \\  & & & \\  & & & \\  & & \\  & & & \\ \end{tabular}
\end{table} 
Table 2: Data extracted from reviewed papers. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Study and Quality** & **Study Group: Age (Crass)** & **Equipment/Perturbation Source/Place of** & \\
**Body Mass (Rgk; Body Height (cm))** & **Aim/Participant Task** & **Impact/Essential Description/Start of the** & **Results/Findings** \\ \hline [PERSON] et al. (2001) [21] & 8 M & Aim: to assess functional postural responses by analyzing the net joint torques (NJT) in the ankles and the two-2-dot of joints, two -2-dot of joints, two -2-dot of joints, two -2-dot of joints, two -2-dot of joints, two -2-dot of joints, two vertical supportive rods and a braking system. & (1) The ankle sum NJT (in AP direction), and the ankle and hip sum NJT (ML) are the global variables being controlled.