Muscle activation patterns during backward walking in people with chronic ankle instability

Abstract

Background: Altered walking patterns are often described in individuals with chronic ankle instability (CAI). Contemporary treatment paradigms recommend backward walking (BW) to improve locomotion in people with musculoskeletal disorders. The purpose of this study was to determine whether muscle activity and activation variability during BW differs between subjects with and without CAI. Methods: Sixteen participants with CAI and 16 healthy controls walked on a treadmill at their self-selected speed under BW and forward walking (FW) conditions. Surface electromyography (EMG) data for the peroneus longus, tibialis anterior, medial gastrocnemius and gluteus medius muscles were collected. EMG amplitude normalized to maximum voluntary isometric contraction (%MVIC) and the standard deviation (SD) of the %MVIC EMG amplitude was calculated throughout the gait cycle. In addition, the area under the curve (AUC) of the %MVIC EMG amplitude was calculated before and after initial contact (pre-IC: 90-100% of stride; post-IC: 0-10% of stride). Results: No differences between groups were noted in the %MVIC amplitude or activation variability (SD of %MVIC EMG) under BW or FW. In both groups, decreased tibialis anterior (p < 0.001) and gluteus medius (p = 0.01), and increased medial gastrocnemius (p < 0.001) activation were observed during pre-and post-IC under BW condition. Conclusion: Participants with CAI and healthy controls have similar muscle activity patterns during BW. Yet, the results should be interpreted with caution due to the heterogeneity of the CAI population.

Inter-limb asymmetry of kinetic and electromyographic during walking in patients with chronic ankle instability

“…However, the results from our muscle activation during walking should be interpreted cautiously. For example, our results are not in line with researchers who reported a decrease in peroneus longus during the initial stance 13 , 60 , or lack of difference between the groups 20 , 21 , 42 , 43 . The variations in the reference task adopted for EMG normalization by different researchers induce a problematic comparison of results across studies.…”

Muscle activation patterns and muscle synergies reflect different modes of coordination during upper extremity movement

“…Our results about the trend of activation coefficients also reflect that the corresponding modules of modulation activation have similar relationships in different individuals, with the CNS as the control center of human movement production modulation. Furthermore, the activation coefficient changes with time, which reflects the changing excitation contribution of each module to the muscle synergy mode ( Geyer and Herr, 2010 ; Balasukumaran et al, 2020 ). However, the relationship between the activation scale and the neural control remains to be further studied.…”

Muscle activations during functional tasks in individuals with chronic ankle instability: a systematic review of electromyographical studies

“…In addition, it was reported that CAI had lower PL EMG-amplitude variability from 1 to 10 %, 32-38 % and 56-100 % of the gait cycle when compared to the controls [37]. In contrast, another study [38] found no difference between CAI and the controls in the PL, TA, MG, and GM activation variability in backward and forward treadmill walking, nor in the activation magnitude of the muscles. The timing of activation during treadmill walking was investigated in one study [36], which reported that PL, TA, LG, RF, BF, and GM were activated earlier in CAI than in the control participants and PL was activated for a longer time interval across the entire stride cycle in CAI compared to the controls [36].…”