Table 1.
Details of Protocol Used in the perturbation intervention training program
| The training sessions # | platform displacement (cm) | platform peak velocity (cm/s) | platform peak acceleration (cm/s2) | Number of unannounced random Perturbations per minute (forward, backward, left, right) |
|---|---|---|---|---|
| 1 | 1–2 cm | 0.1–0.5 m/s | 0.5–3.0 m/s2 | 1 |
| 2 | 2–3 cm | 0.2–0.6 m/s | 0.7–5.0 m/s2 | 2 |
| 3 | 3–4 cm | 0.4–0.6 m/s | 0.9–7.0 m/s2 | 1 |
| 4 | 3–5 cm | 0.5–0.7 m/s | 1.1–7.0 m/s2 | 2 |
| 5 | 4–6 cm | 0.5–0.8 m/s | 1.5–8.0 m/s2 | 2 |
| 6 | 5–6 cm | 0.5–1.0 m/s | 2.0–10.0 m/s2 | 2 |
| 7 | 5–7 cm | 0.7–1.0 m/s | 2.5–12.0 m/s2 | 2 |
| 8 | 6–7 cm | 0.8–1.2 m/s | 3.0–14.0 m/s2 | 3 |
| 9 | 6–8 cm | 1.0–1.5 m/s | 3.5–16.0 m/s2 | 2 |
| 10 | 7–8 cm | 1.2–1.8 m/s | 4.0–16.0 m/s2 | 3 |
| 11 | 7–9 cm | 1.5–2.0 m/s | 5.0–16.0 m/s2 | 2 |
| 12 | 8–9 cm | 1.6–2.2 m/s | 6.0–16.0 m/s2 | 3 |
| 13 | 8–10 cm | 1.8–2.5 m/s | 7.0–16.0 m/s2 | 2 |
| 14 | 9–10 cm | 2.0–2.6 m/s | 8.0–16.0 m/s2 | 3 |
| 15 | 9–11 cm | 2.0–2.8 m/s | 9.0–16.0 m/s2 | 2 |
| 16 | 10–11 cm | 2.2–3.0 m/s | 10.0–16.0 m/s2 | 3 |
| 17 | 11–14 cm | 2.4–3.0 m/s | 11.0–16.0 m/s2 | 2 |
| 18 | 12–14 cm | 2.5–3.0 m/s | 12.0–16.0 m/s2 | 3 |
| 19 | 13–15 cm | 2.6–3.0 m/s | 13.0–16.0 m/s2 | 2 |
| 20 | 14–15 cm | 2.6–3.2 m/s | 14.0–16.0 m/s2 | 3 |
| 21 | 14–16 cm | 2.8–3.2 m/s | 14.0–16.0 m/s2 | 2 |
| 22 | 15–17 cm | 2.8–3.2 m/s | 14.0–16.0 m/s2 | 3 |
| 23 | 16–18 cm | 2.8–3.2 m/s | 14.0–16.0 m/s2 | 2 |
| 24 | 17–18 cm | 2.8–3.2 m/s | 14.0–16.0 m/s2 | 3 |
The 24 training sessions. Each session lasted 20 min, included 3 min warm-up treadmill walking, 14 min of perturbations during comfortable treadmill walking, given in random direction (right, left, forward and backwards), and 3 min of cool down walking. The perturbation training program had 24 levels of difficulty with increasing levels of perturbations (i.e., increased displacement, velocity and accelerations of the horizontal translations). During each session, the listed platform translation unannounced perturbations were delivered in an unpredictable randomized sequence, in the directions indicated (forward, backward, left, and right). Perturbations for the treadmill walking were occur randomly (i.e., occurs in all phases of gait cycle) in order to increase the ecological validity. The perturbation was delivered after 20–30 s approximately every 20 strides and was triggered randomly