The influence of the aquatic environment on the center of pressure, impulses and upper and lower trunk accelerations during gait initiation

Aquatic Therapy after Incomplete Spinal Cord Injury: Gait Initiation Analysis Using Inertial Sensors

“…Furthermore, a reduction (although not significant) in the RMS metric was also found for LT in the ML direction. Overall, these trends are consistent with previous results in a healthy population [ 27 ] and in five cases of iSCI patients [ 19 ], where (median values) were 0.97 and 0.64, were 0.56 and 0.52, were 0.99 and 0.61, and were 0.91 and 0.44 for dry-land and aquatic conditions, respectively. The lower acceleration in water is reasonably explained by the specific physical properties of water (density, hydrostatic pressure, buoyancy, viscosity), and for this reason, aquatic exercises involve not only reduced weight bearing but also an augmented drag.…”

“…Regarding the temporal-related quantities evaluated with the present protocol, no differences were observed in the duration of the APA between the two conditions ( Figure 3 ). The comparison and the values found here match the ones obtained in previous studies analyzing iSCI patients [ 19 ] and healthy populations [ 27 ], although evaluated with force platforms. The first step duration was found to be higher in water (see Figure 3 ) than on dry land, with a median value of 1.44 s (inter-quartile range: 0.42 s) vs. 0.70 s (inter-quartile range: 0.23 s), respectively.…”

“…The first step duration was found to be higher in water (see Figure 3 ) than on dry land, with a median value of 1.44 s (inter-quartile range: 0.42 s) vs. 0.70 s (inter-quartile range: 0.23 s), respectively. Previous studies using center of pressure measurements with a force platform found a similar increase in this phase of gait initiation [ 19 , 27 ]. Specifically, using the center of pressure pattern, Marinho-Buzelli et al [ 19 , 27 ] were able to distinguish between weight transfer to stance limb (in ML direction) and stepping forward (in AP direction) execution phases: the increased duration of the first step execution was mainly attributed to the latter phase in healthy and iSCI patients [ 19 , 27 ].…”

“…Previous studies using center of pressure measurements with a force platform found a similar increase in this phase of gait initiation [ 19 , 27 ]. Specifically, using the center of pressure pattern, Marinho-Buzelli et al [ 19 , 27 ] were able to distinguish between weight transfer to stance limb (in ML direction) and stepping forward (in AP direction) execution phases: the increased duration of the first step execution was mainly attributed to the latter phase in healthy and iSCI patients [ 19 , 27 ]. In the present analysis, it was not possible to identify the two sub-phases of the first step execution phase due to the technology exploited and the limited number of sensors.…”

“…Lastly, the APA was selected from the APA candidates as the one immediately preceding the toe-off of the first step. Once the APA onset and offset were obtained, the following APA measures, as used in Mancini et al [ 20 ] and Marhino-Bulzelli et al [ 19 , 27 ], were computed separately for dry-land and water conditions. Temporal measures: APA duration ( ), defined as the interval between the APA onset and APA offset.…”