Effects of walking in a force field for varying durations on aftereffects and on next day performance

Abstract

This study investigated the effects of walking in an elastic force field (FF) for varying durations (49-1,629 strides) on: (a) the magnitude and duration of aftereffects, (b) performance in the FF on the next day. On day 1 in the FF, subjects (n = 17) showed an initial large error in peak toe velocity during swing (9-61% above baseline) that was largely reduced within the first 40 strides. After FF removal, subjects (16/17) showed aftereffects: (1) reduction in toe velocity (9-38% below baseline), (2) increase in hamstrings muscle activation. While the magnitude of aftereffects did not correlate to FF exposure duration, aftereffects duration did (p < 0.05). During FF exposure on day 2, initial toe velocity error was smaller than on day 1 (13/17 subjects, p < 0.001) regardless of day 1 exposure duration. This was associated with an earlier effective onset in hamstring activation. These results suggest that during walking, even short daily exposures to a FF (> or =49 strides) lead to significant retention of the new movement parameters.

Prism adaptation and generalization during visually guided locomotor tasks

“…Prisms cause locomotor trajectory to deviate in the direction of the prism shift, which adapts over repeated attempts (Kennedy et al 2003;Michel et al 2008;Morton and Bastian 2004). In addition to prism adaptation, studies have shown that the nervous system can adapt to imposed constraints on the walking pattern through the use of a split-belt treadmill to decouple the two limb speeds (Choi and Bastian 2007) or a force applied to the foot or leg during treadmill walking Fortin et al 2009;Savin et al 2010). Taken together, these results support the notion that the nervous system is capable of adapting to altered constraints during locomotion.…”

“…In recent years, the notion of an internal model has been studied extensively for reaching and throwing actions using manipulations of vision and/or limb dynamics (Martin et al 1996a,b;Miall et al 2007;Shadmehr et al 2010;Shadmehr and Mussa-Ivaldi 1994), whereas a limited focus on locomotion has concentrated primarily on manipulations of limb dynamics Choi and Bastian 2007;Fortin et al 2009;Lam et al 2006;Lam and Dietz 2004;Savin et al 2010). For instance, Blanchette and Bouyer (2009) reported that subjects can adapt to an elastic force field applied to the foot during treadmill walking and show negative aftereffects in foot velocity and hamstrings muscle activity following its removal.…”

Training with robot-applied resistance in people with motor-incomplete spinal cord injury: Pilot study

“…Sustained alterations in the movement environment can also mediate longer-term locomotor adaptations via feedback-error learning (recalibration of motor commands based on changes in sensory feedback) [22][23]. Several studies have shown that sustained (several minutes) exposure to forces that resist lower-limb flexion during walking (e.g., using robotic devices or attaching weights around the leg) lead to changes in the locomotor command that are revealed in the aftereffects (e.g., high stepping) that are observed as soon as the forces are removed [24][25][26][27][28][29]. The presence of aftereffects suggests the formation of anticipatory locomotor commands in response to the resistance and is an example of how feedback-error learning can be used to enable locomotor adaptations.…”

“…Significant increases in overground walking speed were observed following training, but no differences were found between resistance and assistance training [33]. Given that resistance training enables specific aftereffects in the dynamic control of the swing phase [24][25][26][27][28][29], it is possible that simple tests of overground walking speed may not adequately capture the particular advantages of this approach to locomotor training, i.e., walking tasks where the dynamic control of leg flexion is particularly important (such as stepping over an obstacle).…”

Effects on Ankle Dorsiflexor Activity to Active and Passive Perturbation Condition in Patients With Stroke

“…Fortin et al (2009) provided a variety of walking environments to healthy subjects using elastic bands on a treadmill to study the alteration of lower limb muscle activity patterns. According to the results, 50 or more steps were sufficient to maintain a modified muscle activity pattern; thus, the researchers suggested that movement errors would decrease for 24 hours after initial exposure to a novel environment.…”