Neuromuscular adaptations in soleus and tibialis anterior muscles in persons with spinal cord injury.
Asta Kizyte, Haocheng Zhang, Emelie Butler Forslund and 2 others
PMID 41239324WHAT IT FOUND
High-functioning individuals with incomplete spinal cord injury required significantly higher muscle electrical activity to match the force of controls.
This suggests they recruit larger or more motor units to compensate for lower firing rates. No differences were found in motor unit synchronization or force variability.
Key findings
01Participants with SCI needed significantly higher normalized EMG amplitudes to achieve the same relative torque as controls, particularly in the soleus.
02Motor unit discharge rates in the tibialis anterior were significantly lower in the SCI group across all movement phases, despite higher EMG amplitude.
03There were no significant differences between groups in motor unit synchronization, co-contraction, or torque variability, ruling out these factors as the primary cause of altered force generation.
STILL TO COME
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What it does not show
The study included only high-functioning individuals with incomplete SCI (ASIA D), so results may not apply to those with more severe injuries or lower motor function. The number of motor units identified in the soleus was low, reducing the robustness of findings for that specific muscle. The trial duration for coherence analysis (16 seconds) was shorter than the recommended minimum (20 seconds), which may have affected the reliability of synchronization estimates. The study was cross-sectional and observational; it describes adaptations but does not test whether these changes are the cause of functional limitations or a result of them.
Declared interests
None declared in the provided text.
The easy way to misread this
Do not interpret the higher EMG amplitude as evidence of muscle hypertrophy or increased strength capacity. The paper states that this higher electrical activity occurred alongside lower motor unit firing rates, suggesting a compensatory neural strategy to maintain force, not an improvement in muscle power.
Summarised by AI from the full paper, without a clinician reviewing it. Check it against the source before it changes what you do. Read it on PubMed →