Abstract
Introduction:
Muscle synergies are defined as fixed patterns of muscle co-activation or a systematic coupling of muscle activation across joints. While healthy adults typically exhibit four to five synergies during walking, post-stroke individuals often present with fewer synergies, reflecting impaired primary motor control. However, the impact of time post-stroke and their clinical implications remains unclear with methodological inconsistencies across studies contributing to variability in findings.
Purpose:
This study investigates the effect of time post-stroke on the number of synergies and its clinical implications. Additionally, it tries to provide recommendations for standardizing muscle synergy analysis in post-stroke walking
Method:
A systematic literature search was conducted in Medline, Embase, and Web of Science (until 05/11/2024) to identify studies reporting muscle synergies during post-stroke walking. Extracted data included participant characteristics, walking parameters, muscles selection, EMG acquisition, and synergy extraction methods. A Chi-square test compared synergy prevalence between sub-acute (7 days to 6 months) and chronic (>6 months) phases after stroke, while Pearson’s correlations examined its associations with walking speed and Fugl-Meyer Lower-Extremity scores.
Results:
A total of 23 studies (574 participants) were included, focusing on the chronic (12 studies) or sub-acute phase (6 studies) after stroke. Some studies included both phases (4 studies) or did not specify the phase (1 study). Participants in the sub-acute phase (N=73/88 [83.0%]) significantly (p<0.001) presented with fewer synergies compared to those in the chronic phase (N=123/211 [58.3%]). The intended correlation statistics were impossible due to underreporting of gait or clinical parameters and within-study heterogeneity. Therefore, recommendations to standardize muscle synergy analysis in post-stroke walking are mandatory. Analysis should compare the paretic, non-paretic, and control legs, include at least eight muscles, and use preferably non-negative matrix factorization (NNMF) with a variance accounted for (VAF) threshold of >90%. Since overground and treadmill walking at a self-selected speed showed comparable results both can be used.
Conclusion:
Fewer synergies were significantly associated with shorter time post-stroke. However, current evidence is insufficient to determine their impact on stroke recovery or gait characteristics. Standardizing muscle synergy analysis will improve studies comparability, enhance understanding of post-stroke motor control, and support phase-specific rehabilitation strategies.
Muscle synergies are defined as fixed patterns of muscle co-activation or a systematic coupling of muscle activation across joints. While healthy adults typically exhibit four to five synergies during walking, post-stroke individuals often present with fewer synergies, reflecting impaired primary motor control. However, the impact of time post-stroke and their clinical implications remains unclear with methodological inconsistencies across studies contributing to variability in findings.
Purpose:
This study investigates the effect of time post-stroke on the number of synergies and its clinical implications. Additionally, it tries to provide recommendations for standardizing muscle synergy analysis in post-stroke walking
Method:
A systematic literature search was conducted in Medline, Embase, and Web of Science (until 05/11/2024) to identify studies reporting muscle synergies during post-stroke walking. Extracted data included participant characteristics, walking parameters, muscles selection, EMG acquisition, and synergy extraction methods. A Chi-square test compared synergy prevalence between sub-acute (7 days to 6 months) and chronic (>6 months) phases after stroke, while Pearson’s correlations examined its associations with walking speed and Fugl-Meyer Lower-Extremity scores.
Results:
A total of 23 studies (574 participants) were included, focusing on the chronic (12 studies) or sub-acute phase (6 studies) after stroke. Some studies included both phases (4 studies) or did not specify the phase (1 study). Participants in the sub-acute phase (N=73/88 [83.0%]) significantly (p<0.001) presented with fewer synergies compared to those in the chronic phase (N=123/211 [58.3%]). The intended correlation statistics were impossible due to underreporting of gait or clinical parameters and within-study heterogeneity. Therefore, recommendations to standardize muscle synergy analysis in post-stroke walking are mandatory. Analysis should compare the paretic, non-paretic, and control legs, include at least eight muscles, and use preferably non-negative matrix factorization (NNMF) with a variance accounted for (VAF) threshold of >90%. Since overground and treadmill walking at a self-selected speed showed comparable results both can be used.
Conclusion:
Fewer synergies were significantly associated with shorter time post-stroke. However, current evidence is insufficient to determine their impact on stroke recovery or gait characteristics. Standardizing muscle synergy analysis will improve studies comparability, enhance understanding of post-stroke motor control, and support phase-specific rehabilitation strategies.
| Original language | English |
|---|---|
| Publication status | Unpublished - 27 Apr 2025 |
| Event | AMS Annual Conference - Duration: 27 Apr 2025 → 27 Apr 2025 |
Conference
| Conference | AMS Annual Conference |
|---|---|
| Period | 27/04/25 → 27/04/25 |