title: Joint Torques and Patellofemoral Force During Single-Leg Assisted and Unassisted Cycling.
abstract: Unassisted single-leg cycling should be replaced by assisted single-leg cycling, given that this last approach has potential to mimic joint kinetics and kinematics from double-leg cycling. However, there is need to test if assisting devices during pedaling effectively replicate joint forces and torque from double-leg cycling.
  
  
  
  To compare double-leg, single-leg assisted, and unassisted cycling in terms of lower-limb kinetics and kinematics.
  
  
  
  Cross-sectional crossover.
  
  
  
  Laboratory.
  
  
  
  14 healthy nonathletes.
  
  
  
  Two double-leg cycling trials (240 ± 23 W) and 2 single-leg trials (120 ± 11 W) at 90 rpm were performed for 2 min using a bicycle attached to a cycle trainer. Measurements of pedal force and joint kinematics of participants' right lower limb were performed during double- and single-leg trials. For the single-leg assisted trial, a custom-made adaptor was used to attach 10 kg of weight to the contralateral crank.
  
  
  
  Peak hip, knee, and ankle torques (flexors and extensors) along with knee-flexion angle and peak patellofemoral compressive force.
  
  
  
  Reduced peak hip-extensor torque (10%) and increased peak knee-flexor torque (157%) were observed at the single-leg assisted cycling compared with the double-leg cycling. No differences were found for peak patellofemoral compressive force or knee-flexion angle comparing double-leg with single-leg assisted cycling. However, single-leg unassisted cycling resulted in larger peak patellofemoral compressive force (28%) and lower knee-flexion angle (3%) than double-leg cycling.
  
  
  
  These results suggest that although single-leg assisted cycling differs for joint torques, it replicates knee loads from double-leg cycling.
authors.affiliation: Exercise Research Laboratory, Federal University of Rio Grande do Sul, Porto Alegre, Brazil.
authors.forename: Rodrigo R
authors.initials: RR
authors.lastname: Bini
authors.forename: Tiago C
authors.initials: TC
authors.lastname: Jacques
authors.forename: Marco A
authors.initials: MA
authors.lastname: Vaz
mesh_terms: D000328:Adult; D000843:Ankle Joint / Q000502:physiology*; D001696:Biomechanical Phenomena; D018592:Cross-Over Studies; D003430:Cross-Sectional Studies; D005080:Exercise Test / Q000295:instrumentation / Q000379:methods*; D006621:Hip Joint / Q000502:physiology*; D006801:Humans; D008297:Male; D057071:Patellofemoral Joint / Q000502:physiology*; D019415:Torque; D055815:Young Adult