Sole vibration improves locomotion through the recovery of joint movements in a mouse cast model.

We investigated the effects of a vibratory stimulus on the plantar surface of the hind limb for motor, sensory, and locomotive function using a mouse cast model. The right knee joint of C57BL/6 male mice (7 weeks, 20 g, n = 31) was flexed with aluminum splint and tape for 6 weeks. These mice were randomly divided into 2 groups (control group, n = 11 and vibration group, n = 12). The mice in the vibration group received vibration on the sole of the ankle for 15 minutes per day, 5 days per week. After the knee joint cast was removed, we measured the range of motion (ROM) of both knee and ankle joints and the sensory threshold of the sole. Further, both walking and swimming movements were analyzed with a digital video. The sole vibration did not affect the passive ROM of the knee joint and sensory threshold after cast removal. However, it increased the ankle dorsiflexion range and improved free walking, swimming, and active movement of the knee joint. In conclusion, we show that the vibration recovered both walking and swimming movements, which resulted from improvements in both the passive ankle dorsiflexion and active knee movement

Range of ankle dorsal and plantar flexion in the control and vibration groups.

<p>(A) Range of ankle dorsal and plantar flexion in the control (n = 11) (Aa and Ac) and vibration groups (n = 12) (Ab and Ad). (B) Average ankle plantar flexion (Ba) and dorsal flexion (Bb).</p

Swimming analysis on the lateral side.

<p>(A) Photographs of the control (Aa) and vibration groups (Ab). (B) Total distance of the Y component (Ba), maximum speed of the Y1 component (Bb), and maximum speed of the Y2 component (Bc).</p

Swimming analysis on the lateral side.

<p>(A) Photographs of the control (Aa) and vibration groups (Ab). (B) Total distance of the Y component (Ba), maximum speed of the Y1 component (Bb), and maximum speed of the Y2 component (Bc).</p

Footprint analysis.

<p>Footprints of the right (red square) and left (blue square) hind limbs were analyzed.</p

Analysis of the swimming at the lateral side.

<p>Photographs of the swimming analysis of the lateral side (Aa and Ab).</p

Gait analysis of the upper side.

<p><b>(A)</b> Gait tracking between the control and vibration groups. (B) Classification of gait tracking shapes in the control and vibration groups. (C) Direction of the turn movement in the control and vibration groups. Comparison of gait distance (Da), maximum speed (Db) and average speed (Dc) between control and vibration groups (* p = 0.002–0.003).</p

Knee extension angle after removal of casting, and the changing of the sensory threshold.

<p>(A) Knee extension angle at 2 weeks after casting. (B) Knee extension angle at 6 weeks after casting. (C) Comparison between 2-week and 6-week casting. White and black circles show the control and vibration groups, respectively. (D) The changing of the sensory threshold between the control and vibration groups.</p

Swimming analysis of the upper side.

<p>(A) Direction of the turn movement in the control and vibration groups (control group: n = 11 and vibration group: n = 12) (Aa). Ratio of the clockwise turn to the total (clockwise plus anticlockwise) turn (Ab). (B) The frequency of the straight swimming. (C) Gait distance (Ca), maximum speed (Cb), and average speed (Cc) between control and vibration groups.</p

Footprint analysis in the control and vibration groups.

<p>(A) Ratio of the swing phase to the stance phase in the control and vibration groups. (B) The paw contact area and stride length. (C) Ratio of the right to the left plantar surface of the foot in the control and vibration groups. (D) Ratio of the right to the left stride length in the control and vibration groups.</p