Tibialis anterior surface electromyography during ankle dorsiflexion as a complementary assessment measure after stroke.

BACKGROUND: The Fugl-Meyer Assessment of Lower Extremity (FMA-LE), Berg Balance Scale (BBS), and Brunnstrom lower-limb stage summarize lower-limb motor and balance function after stroke but do not directly reflect the electrical activity of distal muscles during a specific task. The tibialis anterior (TA) is a primary superficial agonist during active ankle dorsiflexion, and its surface electromyography (sEMG) may provide muscle-specific and task-specific complementary information relevant to foot drop and voluntary distal ankle-foot control. OBJECTIVE: To examine the relationships of TA sEMG measures obtained during active ankle dorsiflexion with lower-limb motor function, balance, and stage of motor recovery in inpatients with ischemic or hemorrhagic stroke within 1 year of onset, and to explore whether short-term improvements in clinical scales were accompanied by corresponding changes in sEMG measures. METHODS: This single-center observational study included 118 participants with supratentorial or infratentorial index stroke lesions. Bilateral TA and gastrocnemius sEMG was recorded during a standardized seated active ankle dorsiflexion task. The primary measures were paretic-side TA average rectified value (ARV) and the TA paretic/non-paretic ratio. Baseline sEMG analyses included 110 participants, clinical longitudinal analyses included 88, and sEMG longitudinal analyses included 81. Spearman correlation, multivariable linear regression, and paired Wilcoxon signed-rank tests were used, with adjustment for multiple comparisons. RESULTS: At baseline, paretic-side TA ARV was lower than non-paretic-side TA ARV. Paretic-side TA ARV showed moderate positive correlations with the FMA-LE, BBS, and Brunnstrom lower-limb stage (ρ = 0.556, 0.492, and 0.496, respectively), as did the TA paretic/non-paretic ratio (ρ = 0.566, 0.440, and 0.417, respectively; all adjusted q < 0.001). Both TA measures remained associated with the FMA-LE and BBS after adjustment for age, sex, stroke type, time from stroke onset to baseline assessment, and paretic side. The FMA-LE, BBS, and Brunnstrom lower-limb stage improved during inpatient rehabilitation, whereas no sEMG measure showed a significant longitudinal change after FDR correction. CONCLUSION: TA sEMG during active ankle dorsiflexion was associated with concurrent lower-limb motor and balance function and may provide muscle-specific and task-specific information complementary to routine clinical scales. Its longitudinal responsiveness and value in clinical practice require further investigation. CLINICAL TRIAL REGISTRATION: https://itmctr.ccebtcm.org.cn/mgt/search, identifier ITMCTR2026000773.