title: Vastus Medialis Hoffmann Reflex Excitability Is Associated With Pain Level, Self-Reported Function, and Chronicity in Women With Patellofemoral Pain.
abstract: To determine the association between the amplitude of vastus medialis (VM) Hoffmann reflex (H-reflex) and pain level, self-reported physical function, and chronicity of pain in women with patellofemoral pain (PFP).
  
  
  
  Cross-sectional study.
  
  
  
  Laboratory of biomechanics and motor control.
  
  
  
  Women diagnosed with PFP (N=15) aged 18 to 35 years.
  
  
  
  Not applicable.
  
  
  
  Data on worst pain level during the previous month, self-reported physical function, and symptom duration (chronicity) were collected from the participants. Maximum evoked responses were obtained by electrical stimulation applied to the femoral nerve and peak-to-peak amplitudes of normalized maximal H-reflexes (maximal Hoffmann reflex/maximal motor wave ratios) of the VM were calculated. A Pearson product-moment correlation matrix (r) was used to explore the relations between the amplitude of VM H-reflex and worst pain during the previous month, self-reported function, and chronicity of pain.
  
  
  
  Strong negative correlations were found between the amplitude of VM H-reflex and worst pain in the previous month (r=-.71; P=.003) and chronicity (r=-.74; P=.001). A strong positive correlation was found between the amplitude of VM H-reflex and self-reported physical function (r=.62; P=.012).
  
  
  
  The strong and significant relations reported in this study suggest that women with PFP showing greater VM H-reflex excitability tend to have lower pain, better physical function, and more recent symptoms. Therefore, rehabilitation strategies designed to increase the excitability of the monosynaptic stretch reflex should be considered in the treatment of women with PFP if their effectiveness is demonstrated in future studies.
authors.affiliation: Physical Therapy Department, School of Science and Technology, University of São Paulo State, Presidente Prudente, São Paulo, Brazil.
authors.forename: Danilo
authors.initials: D
authors.lastname: de Oliveira Silva
authors.affiliation: School of Arts, Sciences, and Humanities, University of São Paulo, São Paulo, Brazil.
authors.forename: Fernando Henrique
authors.initials: FH
authors.lastname: Magalhães
authors.affiliation: Physical Therapy Department, School of Science and Technology, University of São Paulo State, Presidente Prudente, São Paulo, Brazil.
authors.forename: Nathálie Clara
authors.initials: NC
authors.lastname: Faria
authors.affiliation: Post-Graduation Program Interunits Bioengineering, University of São Paulo, São Carlos, Brazil.
authors.forename: Deisi
authors.initials: D
authors.lastname: Ferrari
authors.affiliation: Physical Therapy Department, School of Science and Technology, University of São Paulo State, Presidente Prudente, São Paulo, Brazil.
authors.forename: Marcella Ferraz
authors.initials: MF
authors.lastname: Pazzinatto
authors.affiliation: Discipline of Physiotherapy, Faculty of Health Sciences, University of Sydney, Sydney, NSW, Australia.
authors.forename: Evangelos
authors.initials: E
authors.lastname: Pappas
authors.affiliation: Physical Therapy Department, School of Science and Technology, University of São Paulo State, Presidente Prudente, São Paulo, Brazil. Electronic address: micolis@fct.unesp.br.
authors.forename: Fábio Mícolis
authors.initials: FM
authors.lastname: de Azevedo
mesh_terms: D000293:Adolescent; D000328:Adult; D002908:Chronic Disease; D003430:Cross-Sectional Studies; D004558:Electric Stimulation; D004576:Electromyography; D005260:Female; D005267:Femoral Nerve; D006801:Humans; D010147:Pain Measurement; D046788:Patellofemoral Pain Syndrome / Q000503:physiopathology* / Q000534:rehabilitation; D052097:Quadriceps Muscle / Q000503:physiopathology*; D012021:Reflex, Abnormal / Q000502:physiology*; D057566:Self Report; D055815:Young Adult
keywords: Knee; Motor neurons; Rehabilitation; Spinal cord