Sex Impact on Knee and Ankle Muscle Extensor Forces during Loaded Running

Abstract

Background: This study determined whether the knee and ankle muscle extensor forces increase when running with a body-borne load and whether these forces differ between the sexes. Methods: Thirty-six (twenty male and sixteen female) adults had the knee and ankle extensor force quantified when running 4.0 m/s with four body-borne loads (20, 25, 30, and 35 kg). Peak normalized (BW) and unnormalized (N) extensor muscle force, relative effort, and joint angle and angular velocity at peak muscle force for both the ankle and the knee were submitted to a mixed model ANOVA. Results: Significant load by sex interactions for knee unnormalized extensor force (p = 0.025) and relative effort (p = 0.040) were observed, as males exhibited greater knee muscle force and effort than females and increased their muscle force and effort with additional load. Males also exhibited greater ankle normalized and unnormalized extensor force (p = 0.004, p < 0.001) and knee unnormalized force than females (p = 0.005). The load increased the normalized ankle and knee muscle force (p < 0.001, p = 0.030) and relative effort (p < 0.001, p = 0.044) and the unnormalized knee muscle force (p = 0.009). Conclusion: Running with a load requires greater knee and ankle extensor force, but males exhibited greater increases in muscle force, particularly at the knee, than females.

Variation characteristics of stress distribution in the subchondral bone of the knee joint of judo athletes with long-term stress changes

“…The imbalance between KF and KE groups has been suggested as a potential mechanism for increasing lower extremity injuries such as ACL tears ( 17 , 18 ). Weight-bearing running requires greater knee and ankle extensor strength, with males in particular exhibiting greater muscular strength in the knee than females ( 19 ). However, sports medicine practitioners and sports biomechanics believe that the interaction between the KF and KE muscle groups determines the degree of tibial plateau displacement and ACL injury.…”

Differences in running biomechanics between young, healthy men and women carrying external loads

“…While different studies have separately investigated the running biomechanics of women or men when carrying load ( Brown et al, 2014 ; Willy et al, 2016 ; Unnikrishnan et al, 2021 ; Tong et al, 2023 ), only a few have investigated sex-specific differences ( Lobb et al, 2019 ; Brown et al, 2020 ; Wagers et al, 2022 ). Using individualized computational models that accounted for subject-specific anthropometric characteristics, tibial geometry and material properties, and gait patterns, our recent studies separately analyzed the joint mechanics of men and women when running with load, and suggest that there are sex-specific differences in hip flexion angle with increasing load ( Unnikrishnan et al, 2021 ; Tong et al, 2023 ).…”