title: Muscle-Activation Onset Times With Shoes and Foot Orthoses in Participants With Chronic Ankle Instability.
abstract: BACKGROUND
  Participants with chronic ankle instability (CAI) use an altered neuromuscular strategy to shift weight from double-legged to single-legged stance. Shoes and foot orthoses may influence these muscle-activation patterns.
  
  
  OBJECTIVE
  To evaluate the influence of shoes and foot orthoses on onset times of lower extremity muscle activity in participants with CAI during the transition from double-legged to single-legged stance.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  Musculoskeletal laboratory.
  
  
  METHODS
  A total of 15 people (9 men, 6 women; age = 21.8 ± 3.0 years, height = 177.7 ± 9.6 cm, mass = 72.0 ± 14.6 kg) who had CAI and wore foot orthoses were recruited.
  
  
  METHODS
  A transition task from double-legged to single-legged stance was performed with eyes open and with eyes closed. Both limbs were tested in 4 experimental conditions: (1) barefoot (BF), (2) shoes only, (3) shoes with standard foot orthoses, and (4) shoes with custom foot orthoses (SCFO).
  
  
  METHODS
  The onset of activity of 9 lower extremity muscles was recorded using surface electromyography and a single force plate.
  
  
  RESULTS
  Based on a full-factorial (condition, region, limb, vision) linear model for repeated measures, we found a condition effect (F(3,91.8) = 9.39, P < .001). Differences among experimental conditions did not depend on limb or vision condition. Based on a 2-way (condition, muscle) linear model within each region (ankle, knee, hip), earlier muscle-activation onset times were observed in the SCFO than in the BF condition for the peroneus longus (P < .001), tibialis anterior (P = .003), vastus medialis obliquus (P = .04), and vastus lateralis (P = .005). Furthermore, the peroneus longus was activated earlier in the shoes-only (P = .02) and shoes-with-standard-foot-orthoses (P = .03) conditions than in the BF condition. No differences were observed for the hip muscles.
  
  
  CONCLUSIONS
  Earlier onset of muscle activity was most apparent in the SCFO condition for ankle and knee muscles but not for hip muscles during the transition from double-legged to single-legged stance. These findings might help clinicians understand how shoes and foot orthoses can influence neuromuscular control in participants with CAI.
authors: Musculoskeletal Rehabilitation Research Group, Department of Rehabilitation Sciences;
authors: Bart
authors: B
authors: Dingenen
authors: Musculoskeletal Rehabilitation Research Group, Department of Rehabilitation Sciences;|Thomas More Kempen University College, Mobilab, Geel, Belgium.
authors: Louis
authors: L
authors: Peeraer
authors: Musculoskeletal Rehabilitation Research Group, Department of Rehabilitation Sciences;
authors: Kevin
authors: K
authors: Deschamps
authors: Interuniversity Institute for Biostatistics and Statistical Bioinformatics; and.
authors: Steffen
authors: S
authors: Fieuws
authors: Musculoskeletal Rehabilitation Research Group, Department of Rehabilitation Sciences;|Department of Electrical Engineering, Faculty of Engineering Technology Services, KU Leuven, Belgium;
authors: Luc
authors: L
authors: Janssens
authors: Musculoskeletal Rehabilitation Research Group, Department of Rehabilitation Sciences;
authors: Filip
authors: F
authors: Staes
mesh_terms: D016512:Ankle Injuries / Q000503:physiopathology; D000843:Ankle Joint / Q000502:physiology; D002908:Chronic Disease; D003430:Cross-Sectional Studies; D004576:Electromyography; D005260:Female; D061826:Foot Orthoses; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D007593:Joint Instability / Q000503:physiopathology*; D007719:Knee Joint / Q000502:physiology; D035002:Lower Extremity / Q000502:physiology; D008297:Male; D018482:Muscle, Skeletal / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology; D012775:Shoes; D055815:Young Adult
keywords: ankle sprains; electromyography; footwear; insoles; neuromuscular system