Self-reported walking difficulty and knee osteoarthritis influences limb dynamics and muscle co-contraction during gait

Annalisa Na, Thomas S. Buchanan

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


Knee osteoarthritis (OA) gait is characterized by simultaneous flexor and extensor use, or co-contraction. Co-contraction can stabilize and redirect joint forces. However, co-contraction can push and pull on the femur and tibia that exacerbate OA symptoms and make walking difficult. Such movements are quantifiable by limb dynamics (i.e., linear acceleration and jerk); thus, this study examines limb dynamics and its relationship with co-contraction and OA related walking difficulty. Three groups of age-and-sex-matched subjects with and without OA and walking difficulty (N = 13 per group) walked with electromyography (EMG) on the knee extensors and flexors and inertial measurement units (IMUs) at the femur and tibia. We calculated co-contraction from antagonistic EMG signals and linear acceleration and its derivative jerk from IMUs. We determined group differences using one-way ANOVAs, nonparametric equivalence, and effect sizes, and main and interaction effects of walking difficulty with regression modeling. Medium effect sizes and differences for femoral acceleration (d = 0.64; P =.02) and jerk (d = 0.51; P =.01) were observed between with and without knee OA. Medium to large effect sizes (r = 0.33 to 0.51 and d = 0.81 to 0.97) and differences (P =.01 to 0.05) for tibial acceleration and jerk were obsevered between with and without walking difficulty. Walking difficulty moderated the relationship between tibial jerk and co-contraction (p <.05). Tibial jerk differences were observed based on walking difficulty. The significant interaction effect suggested that walking difficulty explained the relationship between limb dynamics and co-contraction. Perhaps co-contraction levels used by those with knee OA and no walking difficulty are optimal as compared to those with walking difficulty.

Original languageEnglish (US)
Pages (from-to)409-419
Number of pages11
JournalHuman Movement Science
StatePublished - Apr 2019
Externally publishedYes


  • Biomechanics
  • Gait
  • Limb dynamics
  • Muscle co-contraction
  • Osteoarthritis
  • Walking difficulty

ASJC Scopus subject areas

  • Biophysics
  • Orthopedics and Sports Medicine
  • Experimental and Cognitive Psychology


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