Comprehensively Assessing the Acute Femoral Cartilage Response and Recovery after Walking and Drop-Landing: An Ultrasonographic Study.

We compared the acute response and recovery of ultrasonography (US) cartilage outcomes (i.e., thickness, cross-sectional area, and echo intensity) between walking, drop-landing and control conditions in 43 young adults with no history of lower extremity injury. A femoral cartilage US assessment was performed before and after each condition to determine the acute cartilage response and recovery at 15, 30 and 45 min. Percentage change scores from pre- to all post-time points were used for analysis. Acute cartilage response and recovery were analyzed with a 3 × 4 (condition × time) repeated-measures analysis of variance. Greater deformation of the medial and lateral femoral cartilage was observed immediately after both the walking and drop-landing conditions compared with the control condition. Cartilage deformation after the drop-landing condition required longer time to recover compared with the walking condition. The femoral cartilage deformation was not accompanied by concurrent alterations in cartilage echo intensity.