Although foot position and stance width [16] have been investigated, the effect of foot strike position differences during cutting on the knee's valgus angle has not been explored.
Limb rotation, stride length and stance width were measured.
Walking abnormalities occurred in AIA and AIA+NBQX rats, with greater foot rotation (figure 4B) and stance width (figure 4C) and shorter stride length (figure 4D) than naive rats (p<0.05).
Numerous postural and kinematic metrics of gait dynamics were determined by dissecting the time each limb is spent in various portions of the walking phase, including paw area, paw placement angle during stance, stride length, stepping frequency, and stance width, as described in detail in Table 1.
Such alterations included narrowed step angle, increased stance width and reduced swing duration such that the rat kept its forelimbs further apart and on the ground for longer.
Stance width and paw angle were chosen for analysis because they are altered in similar analyses in other mouse models of CMT (Cartoni et al., 2010; d'Ydewalle et al., 2011; Filali et al., 2011), and the timing of stance, swing and stride were chosen because they parallel clinical measures in patients.
To account for the effects of animal size and walking velocity, stride length, step width, percentage stance time, and the single-limb support phase were normalized to the predicted gait profile of weight- and velocity-matched naïve Lewis rats.
Proprietary software was subsequently used to calculate mean spatiotemporal gait parameters (Table 1), including cadence, step and stride length, step width, foot rotation, stance and stride times and swing phase and single and double support durations.
With this prediction, velocity- and weight-independent residuals of stride length, step width, percentage stance time, and the single-limb support phase can be calculated by subtracting the predicted value for a weight- and velocity-matched Lewis rat from the measured value for a Lewis rat with MCLT sham or MCLT + MMT surgery.
Pixel coordinates of the hindpaw position and frame numbers were converted into geometric and time variables, and the following spatiotemporal characteristics were calculated: stride length, step width, percentage stance time, and gait symmetry.
