title: Elevated Knee Joint Kinetics and Reduced Ankle Kinetics Are Present During Jogging and Hopping After Achilles Tendon Ruptures.
abstract: BACKGROUND
  Deficits in plantarflexor function are common after an Achilles tendon rupture. These deficits may result in an altered distribution of joint loads during lower extremity tasks.
  
  
  OBJECTIVE
  We hypothesized that, regardless of treatment, the Achilles tendon-ruptured limb would exhibit deficits in ankle kinematics and joint power while exhibiting elevated knee joint power and patellofemoral joint loads during walking, jogging, and hopping. We further hypothesized that this loading pattern would be most evident during jogging and hopping.
  
  
  METHODS
  Controlled laboratory study.
  
  
  METHODS
  Thirty-four participants (17 participants treated surgically, 17 treated nonsurgically) were tested at a mean 6.1 ± 2.0 years after an Achilles tendon rupture. Lower extremity kinematics and kinetics were assessed while participants completed walking, jogging, and single-legged hopping trials. Patellofemoral joint stress was calculated via a musculoskeletal model. Data were analyzed via mixed-model repeated analyses of variance (α = .05) and the limb symmetry index (LSI).
  
  
  RESULTS
  No differences ( P ≥ .05) were found between the surgical and nonsurgical groups. In both groups, large side-to-side deficits in the plantarflexion angle at toeoff (LSI: 53.5%-73.9%) were noted during walking, jogging, and hopping in the involved limb. Side-to-side deficits in the angular velocity were only present during jogging (LSI: 93.5%) and hopping (LSI: 92.5%). This pattern was accompanied by large deficits in eccentric (LSI: 80.8%-94.7%) and concentric (LSI: 82.2%-84.7%) ankle joint powers in the involved limb during all tasks. Interestingly, only jogging and hopping demonstrated greater knee joint loads when compared with the uninvolved limb. Concentric knee power was greater during jogging (LSI: 117.2%) and hopping (LSI: 115.9%) compared with the uninvolved limb. Similarly, peak patellofemoral joint stress was greater in the involved limb during jogging (LSI: 107.5%) and hopping (LSI: 107.1%), while only hopping had a greater loading rate of patellofemoral joint stress (LSI: 110.9%).
  
  
  CONCLUSIONS
  Considerable side-to-side deficits in plantarflexor function were observed during walking, jogging, and hopping in patients after an Achilles tendon rupture. As a possible compensation, increased knee joint loads were present but only during jogging and hopping.
  
  
  CONCLUSIONS
  These data suggest that after an Achilles tendon rupture, patients may be susceptible to greater mechanical loading of the knee during sporting tasks, regardless of surgical or nonsurgical treatment.
authors.affiliation: Department of Physical Therapy, College of Allied Health Sciences, East Carolina University, Greenville, North Carolina, USA.
authors.forename: Richard W
authors.initials: RW
authors.lastname: Willy
authors.affiliation: Department of Orthopaedics, Institute of Clinical Sciences at Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
authors.forename: Annelie
authors.initials: A
authors.lastname: Brorsson
authors.affiliation: Department of Physical Therapy, College of Allied Health Sciences, East Carolina University, Greenville, North Carolina, USA.
authors.forename: Hayley C
authors.initials: HC
authors.lastname: Powell
authors.affiliation: Department of Physical Therapy, College of Allied Health Sciences, East Carolina University, Greenville, North Carolina, USA.
authors.forename: John D
authors.initials: JD
authors.lastname: Willson
authors.affiliation: Department of Orthopaedics, Institute of Clinical Sciences at Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
authors.forename: Roy
authors.initials: R
authors.lastname: Tranberg
authors.affiliation: Department of Orthopaedics, Institute of Clinical Sciences at Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.|Department of Physical Therapy, University of Delaware, Newark, Delaware, USA.
authors.forename: Karin
authors.initials: K
authors.lastname: Grävare Silbernagel
mesh_terms: D000125:Achilles Tendon / Q000293:injuries* / Q000503:physiopathology; D000328:Adult; D000843:Ankle Joint / Q000502:physiology*; D001696:Biomechanical Phenomena; D005260:Female; D006801:Humans; D007590:Jogging; D007700:Kinetics; D007719:Knee Joint / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D009068:Movement; D057071:Patellofemoral Joint / Q000502:physiology*; D012421:Rupture / Q000503:physiopathology; D016138:Walking
keywords: ankle; biomechanics; gait; hopping; jogging; musculoskeletal modeling