Gender Differences In Kinetics Research Articles

Gender differences of sagittal knee and ankle biomechanics during stair-to-ground descent transition

BackgroundFalls on stairs often result in severe injury and occur twice as frequently in women. However, gender differences in kinetics and kinematics during stair descent are unknown. Thus, this study aimed to determine whether gender differences of knee and ankle biomechanics exist in the sagittal plane during the stair-to-ground descending transition. It was hypothesized that 1) women would reveal higher ground-toe-trochanter angle and lower ground-toe length during stair-to-ground descent transition than men; and 2) women would reveal lower peak knee extension moment during stair-to-ground descent transition than men. MethodsFifteen men and fifteen women were recruited and performed a stair descent activity. Kinetic and kinematic data were obtained using a force plate and motion capture system. FindingsThe women performed the stair descent with a lower peak knee extension moment and a peak knee power at the early weight acceptance phase. The women also revealed a higher ground-toe-trochanter angle and a lower ground-toe length, which indicated a more forward position of the lower extremity relative to the toe contact point at both the initial contact and at the time of peak kinematic and kinetic events. InterpretationThis study found that knee and ankle kinematics and kinetics differed significantly between the genders due to differences in ground-toe-trochanter angle. Women have a different stair descending strategy that reduces the demand of the lower extremity muscle function, but this strategy seems to increase the risk of falls.

Gender Differences in Bile Acid Kinetics After Dietary Challenges

Apart from their role in lipid digestion and sterol homeostasis, bile acids (BA) are known to affect metabolism via FXR and TGR5 receptors. They also modulate energy expenditure and thus became a target in obesity research. As part of the Nutritech project, we analyzed the plasma kinetics of BA after dietary challenges. Healthy volunteers in fasting state underwent an oral glucose tolerance test (OGTT) with 75 g of glucose and blood withdrawals at 0, 15, 30, 60, 90, 120 and 240 minutes. In the following day, the same volunteers endured a mixed meal test (MMT) receiving a liquid meal and having blood samples collected at 0, 30, 60, 120, 240 and 360 minutes. Bile acids were analyzed in plasma by a LC‐MS/MS based method with stable‐isotope labeled reference standards. Both dietary challenges increased the plasma concentration of BA (around 3.85‐fold after the MMT and around 2‐fold after the OGTT). The increase of glycine‐conjugated BA was twice more pronounced than that of taurine‐conjugated entities, while naive BA showed no post‐prandial increase. The increase of primary BA was in average 25% more pronounced than that of secondary BA in both tests. Rather surprising was the finding of gender differences in the kinetics of BA after the OGTT which were not observed after the MMT. These differences originate from an earlier peak in plasma BA in men (at t=30 minutes), whereas women reached 30% higher levels of BA 60 minutes after the glucose ingestion. The observed differences between men and women may have different effects in view of metabolic regulation and their impact shall be considered in future studies.

Kinetic comparison of older men and women during walk-to-stair descent transition

Stair walking is one of the most challenging tasks for older adults, with women reporting higher incidence of falls. The purpose of this study was to investigate the gender differences in kinetics during stair descent transition. Twenty-eight participants (12 male and 16 female; 68.5 and 69.0 years of mean age, respectively) performed stair descent from level walking in a step-over-step manner at a self-selected speed over a custom-made three-step staircase with embedded force plates. Kinematic and force data were combined using inverse dynamics to generate kinetic data for gender comparison. The top and the first step on the staircase were chosen for analysis. Women showed a higher trail leg peak hip abductor moment (−1.0Nm/kg), lower trail leg peak knee extensor moment and eccentric power (0.74Nm/kg and 3.15W/kg), and lower peak concentric power at trail leg ankle joint (1.29W/kg) as compared to men (p<0.05; −0.82Nm/kg, 0.89Nm/kg, 3.83W/kg, and 1.78W/kg, respectively). The lead leg knee eccentric power was also lower in women (p<0.05). This decreased ability to exert knee control during stair descent transition may predispose women to a higher risk of fall.