Comparison of gait initiated on a treadmill (cued and uncued) and overground in healthy individuals

Boyd, S. and Drennan, S. and Ferguson, A. and Millar, J. and Wilcox, M. and Kerr, A. (2018) Comparison of gait initiated on a treadmill (cued and uncued) and overground in healthy individuals. Gait and Posture. P-018. ISSN 0966-6362 (https://doi.org/10.1016/j.gaitpost.2018.06.160)

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Abstract

IntroductionTreadmills are increasingly used in gait rehabilitation due to the practice intensity they offer. Differences between overground and treadmill, in terms of kinematics [1], but also practice variability and cognitive demand, are offered as arguments against treadmill training for the recovery of community walking. Initiating gait from standing is a frequently performed characteristic of community walking which can be problematic for people with neurological conditions such as Parkinson’s disease. Testing the neurobiomechanical differences between gait initiated on a treadmill (cued and uncued) and overground would address concerns regarding the validity of treadmill training and offer suggestions for improvement.Research questionWhat are the neurobiomechanical differences between gait initiated on a treadmill (cued and uncued) and over ground, in healthy participants?MethodsSix healthy participants (aged 25 ± 10.8 years, height 1.76 ± 0.07 m, weight 75.6 ± 17.1 kg) were asked to walk three times on a treadmill (N-Mill, the Netherlands) and over ground at their self-selected comfortable speed. A 12 camera motion capture system (Oxford Metrics, UK), synchronised with a forceplate (Bertec Corp., USA) and an electromyography (EMG) system (Delsys, USA), captured 3D body movement, centre of pressure (CoP) and muscle activity (soleus, gastrocnemius and tibialis anterior) respectively. The data extracted were muscle on/off times, peak CoP displacement (magnitude and timing) and events (gait initiation start and end).ResultsThere were no statistical differences in CoP displacement (magnitude and timing) or gait initiation duration (first shift in CoP until initial contact) between the conditions. The gastrocnemius muscle activated later in the overground trials (50.2 ± 41.8% on swing and 53.0 ± 29.9% on stance side) compared to the cued (8.9 ± 15.9% on swing and 13.7 ± 21.8% on stance side) and uncued (3.8 ± 7.1% on swing and 9.8 ± 12.7% on stance side), see figure. These differences were statistically significant (p < 0.05). No significant differences were found between the activation times of the other muscles for either side (swing or stance).DiscussionA clear difference in the timing of gastrocnemius activity was observed between gait initiated on a treadmill and overground. This suggests a different motor programme may be used to initiate gait on a treadmill. The almost immediate activation of the gastrocnemuius muscles in response to the backward movement of the treadmill has more similarity to a balance reaction [2] than the gait initiation sequence normally observed during overground conditions where forward propulsion is created by the decoupling of the centre of mass and CoP, achieved through deactivation of the plantarflexors. Self-paced treadmills may offer a closer analogue to overground gait initiation and should be tested. These findings should be seen in context of the small healthy sample and EMG data variability.ReferencesWass, E. et al. Gait Posture. 2005; 21: 72–79View in Article | Abstract | Full Text | Full Text PDF | PubMed | Scopus (79) | Google ScholarFiolkowski, P. et al. Neurosci. Lett. 2002; 323: 167–170View in Article | Crossref | PubMed |

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