title: Electromyographic Comparison of Elastic Resistance and Machine Exercises for High-Intensity Strength Training in Patients With Chronic Stroke.
abstract: OBJECTIVE
  To investigate whether elastic resistance training can induce comparable levels of muscle activity as conventional machine training in patients with chronic stroke.
  
  
  METHODS
  Comparative study.
  
  
  METHODS
  Outpatient rehabilitation facility.
  
  
  METHODS
  Stroke patients (N=18) with hemiparesis (mean age, 57 ± 8y).
  
  
  METHODS
  Patients performed 3 consecutive repetitions at 10 repetition maximum of unilateral knee extension and flexion using elastic resistance and conventional machine training.
  
  
  METHODS
  Surface electromyography was measured in vastus lateralis, vastus medialis, biceps femoris, and semitendinosus and was normalized to maximal electromyography (% of max) of the nonparetic leg.
  
  
  RESULTS
  In the paretic leg, agonist muscle activity ranged from 18% to 24% normalized electromyography (% of max) (nEMG) during knee flexion and from 32% to 40% nEMG during knee extension. For knee extension, vastus lateralis nEMG was higher during machine exercise than during elastic resistance exercise (40% [95% confidence interval {CI}, 33-47] vs 32% [95% CI, 25-39]; P=.003). In the nonparetic leg, agonist muscle activity ranged from 54% to 61% during knee flexion and from 52% to 68% during knee extension. For knee flexion semitendinosus nEMG was higher (61% [95% CI, 50-71] vs 54% [95% CI, 44-64]; P=.016) and for knee extension vastus medialis nEMG was higher (68% [95% CI, 60-76] vs 56% [95% CI, 48-64]; P<.001) during machine exercise than during elastic resistance exercise. By contrast, antagonist coactivation was significantly higher during knee flexion when performed using elastic resistance compared with the machine. Lastly, there were no differences in perceived exertion between exercise modalities.
  
  
  CONCLUSIONS
  Machine training appears to induce slightly higher levels of muscle activity in some of the investigated muscles compared to elastic resistance during lower limb strength training in patients with chronic stroke. The higher level of coactivation during knee flexion when performed using elastic resistance suggests that elastic resistance exercises are more difficult to perform. This is likely due to a higher level of movement instability.
authors.affiliation: National Research Centre for the Working Environment, Copenhagen Ø, Denmark.
authors.forename: Jonas
authors.initials: J
authors.lastname: Vinstrup
authors.affiliation: National Research Centre for the Working Environment, Copenhagen Ø, Denmark; Prevention Health Exercise and Sport Research Group, Department of Physical Education and Sports, University of Valencia, Valencia, Spain.
authors.forename: Joaquin
authors.initials: J
authors.lastname: Calatayud
authors.affiliation: National Research Centre for the Working Environment, Copenhagen Ø, Denmark.
authors.forename: Markus D
authors.initials: MD
authors.lastname: Jakobsen
authors.affiliation: National Research Centre for the Working Environment, Copenhagen Ø, Denmark.
authors.forename: Emil
authors.initials: E
authors.lastname: Sundstrup
authors.affiliation: National Research Centre for the Working Environment, Copenhagen Ø, Denmark.
authors.forename: Kenneth
authors.initials: K
authors.lastname: Jay
authors.affiliation: National Research Centre for the Working Environment, Copenhagen Ø, Denmark; Physical Activity and Human Performance Group, SMI, Department of Health Science and Technology, Aalborg University, Aalborg, Denmark.
authors.forename: Mikkel
authors.initials: M
authors.lastname: Brandt
authors.affiliation: Center for Rehabilitation of Brain Injury, University of Copenhagen, Copenhagen Ø, Denmark.
authors.forename: Peter
authors.initials: P
authors.lastname: Zeeman
authors.affiliation: Center for Rehabilitation of Brain Injury, University of Copenhagen, Copenhagen Ø, Denmark.
authors.forename: Jørgen R
authors.initials: JR
authors.lastname: Jørgensen
authors.affiliation: National Research Centre for the Working Environment, Copenhagen Ø, Denmark; Physical Activity and Human Performance Group, SMI, Department of Health Science and Technology, Aalborg University, Aalborg, Denmark. Electronic address: lla@nrcwe.dk.
authors.forename: Lars L
authors.initials: LL
authors.lastname: Andersen
mesh_terms: D002908:Chronic Disease; D004548:Elasticity; D004576:Electromyography; D005260:Female; D006801:Humans; D007866:Leg / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D010291:Paresis / Q000503:physiopathology* / Q000534:rehabilitation*; D055070:Resistance Training / Q000379:methods*; D020521:Stroke / Q000503:physiopathology*; D000071939:Stroke Rehabilitation; D016896:Treatment Outcome
keywords: Electromyography; Physical therapy specialty; Rehabilitation; Resistance training; Stroke