How does external lateral stabilization constrain normal gait, apart from improving medio-lateral gait stability?

Abstract

Background: The effect of external lateral stabilization on medio-lateral gait stability has been investigated previously. However, existing lateral stabilization devices not only constrain lateral motions but also transverse and frontal pelvis rotations. This study aimed to investigate the effect of external lateral stabilization with and without constrained transverse pelvis rotation on mechanical and metabolic gait features. Methods: We undertook two experiments with 11 and 10 young adult subjects, respectively. Kinematic, kinetic and breath-by-breath oxygen consumption data were recorded during three walking conditions (normal walking (Normal), lateral stabilization with (Free) and without transverse pelvis rotation (Restricted)) and at three speeds (0.83, 1.25 and 1.66 m s −1 ) for each condition. In the second experiment, we reduced the weight of the frame, and allowed for longer habituation time to the stabilized conditions. Results: External lateral stabilization significantly reduced the amplitudes of the transverse and frontal pelvis rotations, in addition to medio-lateral, anterior–posterior, and vertical pelvis displacements, transverse thorax rotation, arm swing, step length and step width. The amplitudes of free vertical moment, anterior–posterior drift over a trial, and energy cost were not significantly influenced by external lateral stabilization. The removal of pelvic rotation restrictions by our experimental set-ups resulted in normal frontal pelvis rotation in Experiment 1 and significantly higher transverse pelvis rotation in Experiment 2, although transverse pelvis rotation still remained significantly less than in the Normal condition. Step length increased with the increased transverse pelvis rotation. Conclusion: Existing lateral stabilization set-ups not only constrain medio-lateral motions (i.e. medio-lateral pelvis displacement) but also constrain other movements such as transverse and frontal pelvis rotations, which leads to several other gait changes such as reduced transverse thorax rotation, and arm swing. Our new set-ups allowed for normal frontal pelvis rotation and more transverse pelvis rotation (yet less than normal). However, this did not result in more normal thorax rotation and arm swing. Hence, to provide medio-lateral support without constraining other gait variables, more elaborate set-ups are needed.

The effect of external lateral stabilization on energy cost of walking – A systematic review and meta-analysis

“…We included eight studies (Figure 3 and Table 2), with a range of 8-17 participants per study, reporting on a total of participants. Walking trials of five [14][15][16][17] or seven [12,13,9,10] minutes were used in these studies. The last two [14,15] or three [12,13,9,16,17,10] minutes of these walking trials were selected to calculate net energy cost.…”

“…Walking trials of five [14][15][16][17] or seven [12,13,9,10] minutes were used in these studies. The last two [14,15] or three [12,13,9,16,17,10] minutes of these walking trials were selected to calculate net energy cost. Stabilized walking was studied at several walking speeds (mean 1.10 m/s, range 0.83-1.70 m/s).…”

“…Stabilized walking was studied at several walking speeds (mean 1.10 m/s, range 0.83-1.70 m/s). Most studies [12,1,[14][15][16][17], but not all [13], randomized the within participant order of non-stabilized and stabilized walking among the participants. In most studies, participants had to walk with restricted transverse and frontal plane pelvis rotations as well as restricted vertical pelvis displacement [12,13,9,14,15,10], and had to hold their arms crossed across their chest in stabilized walking (to avoid contacting the external stabilizer) [12,13,9].…”

“…Previous studies have experimentally investigated the energy costs required for the control of mediolateral stability [12,13,9,[14][15][16][17]10], using a spring-like construction that externally stabilizes walking in the medio-lateral direction (see Figure 1). However, results were inconsistent [12,13,9,[14][15][16][17]10].…”

“…Previous studies have experimentally investigated the energy costs required for the control of mediolateral stability [12,13,9,[14][15][16][17]10], using a spring-like construction that externally stabilizes walking in the medio-lateral direction (see Figure 1). However, results were inconsistent [12,13,9,[14][15][16][17]10]. For example, on the one hand, Donelan et al [9] reported a significant reduction in energy cost when walking with external lateral stabilization at both preferred and zero step widths.…”