Original research| Volume 102, ISSUE 5, P914-924, May 2021

Unilateral Strength Training of the Less Affected Hand Improves Cortical Excitability and Clinical Outcomes in Patients With Subacute Stroke: A Randomized Controlled Trial

  • Nasrin Salehi Dehno
    Physical Therapy Department, School of Rehabilitation Sciences, Shiraz University of Medical Sciences, Shiraz, Iran

    Student Research Committee, Shiraz University of Medical Sciences, Shiraz, Iran
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  • Fahimeh Kamali
    Corresponding author Fahimeh Kamali, PhD, Physical Therapy Department, School of Rehabilitation Sciences, Shiraz University of Medical Sciences, Abiverdi 1, Chamran Blvd, P.O. Box: 71947-33669, Shiraz, Iran.
    Physical Therapy Department, School of Rehabilitation Sciences, Shiraz University of Medical Sciences, Shiraz, Iran

    Rehabilitation Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
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  • Abdolhamid Shariat
    Clinical Neurology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
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  • Shapour Jaberzadeh
    Department of Physiotherapy, School of Primary and Allied Health Care, Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, Australia
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Published:January 15, 2021DOI:


      • Unilateral strength training resulted in modulation of cortical excitability in patients with subacute stroke.
      • Unilateral strength training combined with conventional physiotherapy was more effective in improving cortical excitability and clinical outcomes.
      • These findings support the notion that modulation of cortical excitability facilitates motor recovery.



      To investigate whether unilateral strength training helps improve cortical excitability and clinical outcomes after stroke.


      Randomized controlled trial.


      Rehabilitation sciences research center.


      Patients with subacute stroke (N=26) were randomly assigned to a control group (n=13) or the experimental group (n=13).


      Participants in both groups received conventional physiotherapy. The experimental group also received unilateral strength training of the less affected wrist extensors. Interventions were applied for 4 weeks (12 sessions, 3 d/wk).

      Main Outcome Measures

      Cortical excitability in both the ipsilesional hemisphere (ipsiH) and contralesional hemisphere (contraH) was assessed by measuring resting motor threshold (RMT), active motor threshold (AMT), motor evoked potential (MEP), and cortical silent period (CSP) at baseline and after the 4-week intervention period. Clinical outcomes were obtained by evaluating wrist extension strength in both the more affected and less affected hands, upper extremity motor function, activities of daily living (ADL), and spasticity.


      The experimental group showed greater MEP amplitude (P=.001) in the ipsiH and shorter CSP duration in both the ipsiH (P=.042) and contraH (P=.038) compared with the control group. However, the reductions in RMT and AMT in both hemispheres were not significantly different between groups. Improvements in wrist extension strength in the more affected (P=.029) and less affected (P=.001) hand, upper extremity motor function (P=.04), and spasticity (P=.014) were greater in the experimental group. No significant difference in ADLs was detected between groups.


      A combination of unilateral strength training and conventional physiotherapy appears to be a beneficial therapeutic modality for improving cortical excitability and some clinical outcomes in patients with stroke.


      List of abbreviations:

      ADL (activities of daily living), AMT (active motor threshold), contraH (contralesional hemisphere), CSE (corticospinal excitability), CSP (cortical silent period), ECR (extensor carpi radialis), EMG (electromyography), FMA (Fugl-Meyer Motor Assessment), ipsiH (ipsilesional hemisphere), MBI (Modified Barthel Index), MEP (motor evoked potential), MCID (minimally clinically important difference), M1 (primary motor cortex), MMAS (Modified Modified Ashworth scale), MRC (Medical Research Council), MSO (maximum stimulator output), MVIC (maximal voluntary isometric contraction), RMT (resting motor threshold), TMS (transcranial magnetic stimulation), UE (upper extremity)
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