The Clinical Assessment of Eccentric and Concentric Stepping Kinetics has Utility in Older African American Men with...

Stair navigation is physically demanding for individuals with knee osteoarthritis and may result in movement asymmetries that can be quantified using kinetic analysis and force-time parameters. Thus, the purpose of this cross-sectional study was to determine if kinetic force-time parameter asymmetries are present in individuals with knee osteoarthritis and associated with functional outcomes.

Forty-six older male veterans (61.6 ± 5.6 years) participated. More and less involved legs were defined using the Kellgren and Lawrence (KL) scale and self-reported pain. Kinetics were measured with the Neurocom® Step Up and Over test and quantified with the lift-up index, impact index, movement time, and stair-stepping smoothness. Smoothness was calculated from the level of intermittency in acceleration and deceleration during the concentric and eccentric test movements.

Smoothness was the only force-time parameter to demonstrate an asymmetry. Greater smoothness values were observed for the less-involved leg (p<0.001, 95% CI: 1.22 to 3.64, d=1.17) and were positively associated with gait speed (more-involved: r=0.47, p<0.01; lessinvolved: r=0.53, p<0.01), Knee Injury and Osteoarthritis Outcome Score (KOOS) Symptom (more-involved: r=0.31, p<0.05; less-involved: r=0.39, p<0.01) and activities of daily living (more-involved: r=0.32, p<0.05; less-involved: r=0.39, p<0.05) subscales, and isokinetic knee extension strength (more-involved: r=0.31, p<0.05; less-involved: r=0.42, p<0.01).

Stair-stepping smoothness was diminished in the more involved leg and was associated with worse gait speed, patient-reported outcomes, and knee strength. This observation may reflect compromised motor control associated with decreased strength and greater disease severity in the more-involved leg.