Differences in knee joint moments between individuals who are living with obesity and those of a healthy weight when negotiating stairs

Background: Individuals who are living with obesity often adopt alternative lower limb walking mechanics compared to persons with a healthy weight. Stair negotiation is a common activity of daily living that, when used consistently with diet and other physical activity, can help promote the reversal of health-related risk factors associated with people who are obese. The purpose of this study was to determine how stair negotiation affects normalized and non-normalized peak knee extension and abduction moments in young adults who live with obesity (BMI between 30 and 40 kg/m²) compared to adults with a healthy weight (BMI between 18.5 and 25 kg/m²). Methods: Fifteen young adults living with obesity and fifteen with a healthy weight performed stair ascent and descent walking trials on a 3-step instrumented staircase at a self-selected walking speed. A one-way ANCOVA (covariate: gait speed) was used to compare knee moment variables between groups. Results: No significant differences were found between groups in peak knee joint moments normalized to body mass. The individuals living with obesity demonstrated significantly larger non-normalized peak knee extension moments during stair ascent and descent but no differences in the non-normalized peak knee abduction moments for stair ascent or descent. Conclusion: Results of this study indicate differences in non-normalized peak knee extension moments between BMI groups. The young age of the obese group may have contributed to minimal differences overall. Future research should determine how these findings differ in an older obese population and how using a handrail would affect these results.