title: Lower-extremity biomechanics during forward and lateral stepping activities in older adults.
abstract: OBJECTIVE
  To characterize the lower-extremity biomechanics associated with stepping activities in older adults.
  
  
  METHODS
  Repeated-measures comparison of kinematics and kinetics associated with forward step-up and lateral step-up activities.
  
  
  BACKGROUND
  Biomechanical analysis may be used to assess the effectiveness of various 'in-home activities' in targeting appropriate muscle groups and preserving functional strength and power in elders.
  
  
  METHODS
  Data were analyzed from 21 participants (mean 74.7 yr (standard deviation, 4.4 yr)) who performed the forward and lateral step-up activities while instrumented for biomechanical analysis. Motion analysis equipment, inverse dynamics equations, and repeated measures ANOVAs were used to contrast the maximum joint angles, peak net joint moments, angular impulse, work, and power associated with the activities.
  
  
  RESULTS
  The lateral step-up resulted in greater maximum knee flexion (P<0.001) and ankle dorsiflexion angles (P<0.01). Peak joint moments were similar between exercises. The forward step-up generated greater peak hip power (P<0.05) and total work (P<0.001); whereas, the lateral step-up generated greater impulse (P<0.05), work (P<0.01), and power (P<0.05) at the knee and ankle.
  
  
  CONCLUSIONS
  In older adults, the forward step-up places greater demand on the hip extensors, while lateral step-up places greater demand on the knee extensors and ankle plantar flexors.
  
  
  CONCLUSIONS
  Clinicians may use data from biomechanical analyses of in-home exercises to more effectively target specific lower-extremity muscle groups when prescribing exercise activities for older adults. The forward step-up is recommended for maintaining or improving hip extensor performance; whereas, the lateral step-up is recommended when targeting the knee extensors and ankle plantar flexors.
authors.affiliation: Musculoskeletal Biomechanics Research Laboratory, Department of Biokinesiology and Physical Therapy, University of Southern California, 1540 E. Alcazar St., CHP-155, Los Angeles, CA 90033, USA.
authors.forename: Man-Ying
authors.initials: MY
authors.lastname: Wang
authors.forename: Sean
authors.initials: S
authors.lastname: Flanagan
authors.forename: Joo-Eun
authors.initials: JE
authors.lastname: Song
authors.forename: Gail A
authors.initials: GA
authors.lastname: Greendale
authors.forename: George J
authors.initials: GJ
authors.lastname: Salem
mesh_terms: D000203:Activities of Daily Living; D000368:Aged / Q000502:physiology*; D000369:Aged, 80 and over; D000842:Ankle / Q000502:physiology; D001696:Biomechanical Phenomena; D015331:Cohort Studies; D015444:Exercise / Q000502:physiology*; D005260:Female; D006615:Hip / Q000502:physiology; D006801:Humans; D007717:Knee / Q000502:physiology; D008124:Locomotion / Q000502:physiology*; D035002:Lower Extremity / Q000502:physiology*; D008297:Male; D009068:Movement / Q000502:physiology; D016059:Range of Motion, Articular / Q000502:physiology; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D019415:Torque