Gender Differences In Cumulative Knee Loading During Walking And Running

Female individuals are more likely to develop knee osteoarthritis (KOA) compared to male individuals, yet the underlying mechanisms attributed to this discrepancy are unclear. In females and males combined, greater peak knee adduction moment (KAM) and medial joint contact force (MJCF) are associated with the development and progression of KOA. Although peak KAM and MJCF are consistently associated with KOA, these peaks typically are not greater in females vs. males. Cumulative stress on the knee has been linked to articular cartilage damage, so cumulative loads per unit distance (PUD) traveled may give further insight into why females are more susceptible to KOA than males. Due to the increased rates of KOA in females and the fact that females typically need to perform more strides than longer-legged males over a given distance, we hypothesized that females would experience greater cumulative PUD KAM and MJCF compared to males. PURPOSE: To investigate differences in cumulative biomechanical risk factors associated with KOA between male and female individuals. METHODS: Eight healthy participants (4 females, 23 ± 3.7 yrs.; 4 males, 25.3 ± 3.8 yrs.) walked and ran across force plates at self-selected speeds, while motion capture data was recorded. V3D calculated KAM was scaled by bodyweight (BW) and height (Ht), and reduction modeling approach calculated MJCF was scaled by BW. Differences in PUD KAM and MJCF were examined using one-tailed unpaired Student’s t-tests. Differences in speed were examined using two-tailed unpaired Student’s t-tests. RESULTS: Walking and running speeds were similar between groups. During walking, females experienced greater PUD KAM (female = 1.06 ± 0.65 %BW*Ht/m, male = 0.30 ± 0.16 %BW*Ht/m, p = 0.045), but there were no significant differences in peak KAM between groups. Other variables did not reach statistical significance. CONCLUSIONS: The higher prevalence of KOA experienced by females may be partially attributed to greater PUD biomechanical risk factors, as females walked with greater PUD KAM compared to males. Planned future research will analyze these risk factors among both sexes in larger sample sizes. Interactions of these gender differences in mechanical loads with joint geometry, cartilage tissue properties, and sex hormones may also affect the osteoarthritis risk. UM Ventures: Medial Device Development Funding