title: Quadriceps muscles activity during gait: comparison between PFPS subjects and healthy control.
abstract: OBJECTIVE
  The purpose of the study was to evaluate if during a common activity as walking, altered quadriceps muscular activity may be present in patellofemoral pain syndrome (PFPS) patients.
  
  
  METHODS
  Forty subjects with clinically diagnosed PFPS and forty healthy males matching in age, weight, height and level of sport activity were enrolled in the study. Subjects were asked to walk on an instrumented walking path at their self-selected speed. Force platform and motion tracking system were used for the analysis of the gait. Wireless surface EMG probes were used to evaluate quadriceps muscles activity. Rectus femoris, vastus medialis and lateralis activity percentage, onset and offset time, walking speed, cadence, step length, stride length, knee ROM during gait were measured and reported. Tegner activity questionnaire was reported.
  
  
  RESULTS
  Patient group showed a significant increasing in all quadriceps muscles activity when compared to the control (p < 0.05). In particular, for VM and VL muscle onset time was anticipated and offset time was postponed in PFPS group when compared with healthy group (p < 0.05). Knee range of motion during walking was significantly decreased in the patient group.
  
  
  CONCLUSIONS
  Young athletes with PFPS showed increased length of quadriceps muscles activity and reduced functional knee Rom while walking, comparing with healthy subjects, in particular muscular onset was anticipated in respect of the loading response event of the gait. Nonetheless, walking parameters were not affected by these alterations.
authors.affiliation: Institute of Orthopedic and Traumatology, Catholic University, 'Agostino Gemelli' Hospital, Largo Francesco Vito, 1, 00168, Rome, Italy. marco.freddolini@gmail.com.|Biomechanics Division, Institute of Translational Research for Musculoskeletal System 'Nicola Cerulli', via Einstein 12/L, 52100, Arezzo, Italy. marco.freddolini@gmail.com.
authors.forename: M
authors.initials: M
authors.lastname: Freddolini
authors.affiliation: Institute of Orthopedic and Traumatology, Catholic University, 'Agostino Gemelli' Hospital, Largo Francesco Vito, 1, 00168, Rome, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Placella
authors.affiliation: Institute of Orthopedic and Traumatology, Catholic University, 'Agostino Gemelli' Hospital, Largo Francesco Vito, 1, 00168, Rome, Italy.|Biomechanics Division, Institute of Translational Research for Musculoskeletal System 'Nicola Cerulli', via Einstein 12/L, 52100, Arezzo, Italy.
authors.forename: G L
authors.initials: GL
authors.lastname: Gervasi
authors.affiliation: Orthopaedics and Traumatology Clinic, 'P. Giaccone' Hospital, University of Palermo, Via del Vespro, 131, 90127, Palermo, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Morello
authors.affiliation: Institute of Orthopedic and Traumatology, Catholic University, 'Agostino Gemelli' Hospital, Largo Francesco Vito, 1, 00168, Rome, Italy.|Biomechanics Division, Institute of Translational Research for Musculoskeletal System 'Nicola Cerulli', via Einstein 12/L, 52100, Arezzo, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Cerulli
mesh_terms: D003430:Cross-Sectional Studies; D005684:Gait / Q000502:physiology*; D006801:Humans; D008297:Male; D046788:Patellofemoral Pain Syndrome / Q000503:physiopathology*; D052097:Quadriceps Muscle / Q000503:physiopathology*; D055815:Young Adult
keywords: EMG; Knee; Patellofemoral pain syndrome; Vastus lateralis; Vastus medialis; Walking