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Self-selected gait speed--over ground versus self-paced treadmill walking, a solution for a paradox.

Plotnik M, Azrad T, Bondi M, Bahat Y, Gimmon Y, Zeilig G, Inzelberg R, Siev-Ner I - J Neuroeng Rehabil (2015)

Bottom Line: We compared over ground walking vs.Gait speed was compared across conditions for four 10 m long segments (7.5 - 17.5, 30.5 - 40.5, 55.5 - 65.5 and 78.5-88.5 m).We propose that the gait research community joins forces to standardize the use of SP TMs, e.g., by unifying protocols or gathering normative data.

View Article: PubMed Central - PubMed

Affiliation: Center of Advanced Technologies in Rehabilitation, Sheba Medical Center, Tel Hashomer, Israel. meir.plotnik@sheba.health.gov.il.

ABSTRACT

Background: The study of gait at self-selected speed is important. Traditional gait laboratories being relatively limited in space provide insufficient path length, while treadmill (TM) walking compromises natural gait by imposing speed variables. Self-paced (SP) walking can be realized on TM using feedback-controlled belt speed. We compared over ground walking vs. SP TM in two self-selected gait speed experiments: without visual flow, and while subjects were immersed in a virtual reality (VR) environment inducing natural visual flow.

Methods: Young healthy subjects walked 96 meters at self-selected comfortable speed, first over ground and then on the SP TM without (n=15), and with VR visual flow (n=11). Gait speed was compared across conditions for four 10 m long segments (7.5 - 17.5, 30.5 - 40.5, 55.5 - 65.5 and 78.5-88.5 m).

Results: During over ground walking mean (± SD) gait speed was equal for both experimental groups (1.50 ± 0.13 m/s). Without visual flow, gait speed over SP TM was smaller in the first and second epochs as compared to over ground (first: 1.15 ±0.18 vs. second: 1.53 ± 0.13 m/s; p<0.05), and was comparable in the third and fourth (1.45 ± 0.19 vs. 1.49 ± 0.15 m/s; p>0.3). With visual flow, gait speed became comparable to that of over ground performance already in the first epoch (1.43 ± 0.22 m/s; p>0.17). Curve fitting analyses estimated that steady state velocity in SP TM walking is reached after shorter distanced passed with visual flow (24.6 ± 14.7 m) versus without (36.5 ± 18.7 m, not statistically significant; p=0.097). Steady state velocity was estimated to be higher in the presence of visual flow (1.61 ± 0.17 m/s) versus its absence (1.42 ± 1.19 m/s; p<0.05).

Conclusions: The SP TM walking is a reliable method for recording typical self-selected gait speed, provided that sufficient distance is first passed for reaching steady state. Seemingly, in the presence of VR visual flow, steady state of gait speed is reached faster. We propose that the gait research community joins forces to standardize the use of SP TMs, e.g., by unifying protocols or gathering normative data.

No MeSH data available.


Related in: MedlinePlus

Estimation of reaching steady state gait velocity values. Two typical examples of SP TM trials: one without the presence of visual virtual flow (EXPERIMENT A - black dots), and one in the presence of virtual visual flow (EXPERIMENT B gray dots). The respective exponential functions are depicted (solid - and dashed - lines, respectively). In these examples the estimated steady state is higher for the example from EXPERIMENT B (1.66 m/s) and lower for the example from EXPERIMENT A (1.42 m/s), with twice as higher curvature estimation for the former (0.19 vs. 0.09 1/m). It can be seen that in agreement with these estimations, the D95 value is about half in the example from EXPERIMENT B (19.9 m gray arrow head) as compared to the example from EXPERIMENT A (45.1 m). Refer to Table 2, for group values and statistical comparisons.
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Fig5: Estimation of reaching steady state gait velocity values. Two typical examples of SP TM trials: one without the presence of visual virtual flow (EXPERIMENT A - black dots), and one in the presence of virtual visual flow (EXPERIMENT B gray dots). The respective exponential functions are depicted (solid - and dashed - lines, respectively). In these examples the estimated steady state is higher for the example from EXPERIMENT B (1.66 m/s) and lower for the example from EXPERIMENT A (1.42 m/s), with twice as higher curvature estimation for the former (0.19 vs. 0.09 1/m). It can be seen that in agreement with these estimations, the D95 value is about half in the example from EXPERIMENT B (19.9 m gray arrow head) as compared to the example from EXPERIMENT A (45.1 m). Refer to Table 2, for group values and statistical comparisons.

Mentions: Figure 5 depicts two representative data sets, from SP TM trials, with and without VR visual flow (EXPERIMENT B and A, respectively). It can be seen that the exponential function (c.f., Methods) fits well the data, resembling the shape of the relation depicted for the grand averages shown in Figure 3.Figure 5


Self-selected gait speed--over ground versus self-paced treadmill walking, a solution for a paradox.

Plotnik M, Azrad T, Bondi M, Bahat Y, Gimmon Y, Zeilig G, Inzelberg R, Siev-Ner I - J Neuroeng Rehabil (2015)

Estimation of reaching steady state gait velocity values. Two typical examples of SP TM trials: one without the presence of visual virtual flow (EXPERIMENT A - black dots), and one in the presence of virtual visual flow (EXPERIMENT B gray dots). The respective exponential functions are depicted (solid - and dashed - lines, respectively). In these examples the estimated steady state is higher for the example from EXPERIMENT B (1.66 m/s) and lower for the example from EXPERIMENT A (1.42 m/s), with twice as higher curvature estimation for the former (0.19 vs. 0.09 1/m). It can be seen that in agreement with these estimations, the D95 value is about half in the example from EXPERIMENT B (19.9 m gray arrow head) as compared to the example from EXPERIMENT A (45.1 m). Refer to Table 2, for group values and statistical comparisons.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4374285&req=5

Fig5: Estimation of reaching steady state gait velocity values. Two typical examples of SP TM trials: one without the presence of visual virtual flow (EXPERIMENT A - black dots), and one in the presence of virtual visual flow (EXPERIMENT B gray dots). The respective exponential functions are depicted (solid - and dashed - lines, respectively). In these examples the estimated steady state is higher for the example from EXPERIMENT B (1.66 m/s) and lower for the example from EXPERIMENT A (1.42 m/s), with twice as higher curvature estimation for the former (0.19 vs. 0.09 1/m). It can be seen that in agreement with these estimations, the D95 value is about half in the example from EXPERIMENT B (19.9 m gray arrow head) as compared to the example from EXPERIMENT A (45.1 m). Refer to Table 2, for group values and statistical comparisons.
Mentions: Figure 5 depicts two representative data sets, from SP TM trials, with and without VR visual flow (EXPERIMENT B and A, respectively). It can be seen that the exponential function (c.f., Methods) fits well the data, resembling the shape of the relation depicted for the grand averages shown in Figure 3.Figure 5

Bottom Line: We compared over ground walking vs.Gait speed was compared across conditions for four 10 m long segments (7.5 - 17.5, 30.5 - 40.5, 55.5 - 65.5 and 78.5-88.5 m).We propose that the gait research community joins forces to standardize the use of SP TMs, e.g., by unifying protocols or gathering normative data.

View Article: PubMed Central - PubMed

Affiliation: Center of Advanced Technologies in Rehabilitation, Sheba Medical Center, Tel Hashomer, Israel. meir.plotnik@sheba.health.gov.il.

ABSTRACT

Background: The study of gait at self-selected speed is important. Traditional gait laboratories being relatively limited in space provide insufficient path length, while treadmill (TM) walking compromises natural gait by imposing speed variables. Self-paced (SP) walking can be realized on TM using feedback-controlled belt speed. We compared over ground walking vs. SP TM in two self-selected gait speed experiments: without visual flow, and while subjects were immersed in a virtual reality (VR) environment inducing natural visual flow.

Methods: Young healthy subjects walked 96 meters at self-selected comfortable speed, first over ground and then on the SP TM without (n=15), and with VR visual flow (n=11). Gait speed was compared across conditions for four 10 m long segments (7.5 - 17.5, 30.5 - 40.5, 55.5 - 65.5 and 78.5-88.5 m).

Results: During over ground walking mean (± SD) gait speed was equal for both experimental groups (1.50 ± 0.13 m/s). Without visual flow, gait speed over SP TM was smaller in the first and second epochs as compared to over ground (first: 1.15 ±0.18 vs. second: 1.53 ± 0.13 m/s; p<0.05), and was comparable in the third and fourth (1.45 ± 0.19 vs. 1.49 ± 0.15 m/s; p>0.3). With visual flow, gait speed became comparable to that of over ground performance already in the first epoch (1.43 ± 0.22 m/s; p>0.17). Curve fitting analyses estimated that steady state velocity in SP TM walking is reached after shorter distanced passed with visual flow (24.6 ± 14.7 m) versus without (36.5 ± 18.7 m, not statistically significant; p=0.097). Steady state velocity was estimated to be higher in the presence of visual flow (1.61 ± 0.17 m/s) versus its absence (1.42 ± 1.19 m/s; p<0.05).

Conclusions: The SP TM walking is a reliable method for recording typical self-selected gait speed, provided that sufficient distance is first passed for reaching steady state. Seemingly, in the presence of VR visual flow, steady state of gait speed is reached faster. We propose that the gait research community joins forces to standardize the use of SP TMs, e.g., by unifying protocols or gathering normative data.

No MeSH data available.


Related in: MedlinePlus