Shultz S J, Sander T C, Kirk S E, Perrin D H
Applied Neuromechanics Research Laboratory, Department of Exercise and Sport Science, University of North Carolina, Greensboro, NC 27402-6170, USA.
J Sports Med Phys Fitness. 2005 Dec;45(4):594-603.
To elucidate the hormonal influences on sex differences in knee joint behavior, normal-menstruating females were compared to males on serum hormone levels and anterior knee joint laxity (displacement at 46N, 89N and 133N) and stiffness (Linear slope of deltaForce/deltaDisplacement for 46-89N and 89-133N) across the female menstrual cycle.
Twenty-two females were tested daily across one complete menstrual cycle, and 20 males were tested once per week for 4 weeks. Five days each representing the hormonal milieu for menses, the initial estrogen rise near ovulation, and the early and late luteal phases (total of 20 days) were compared to the average value obtained from males across their 4 test days.
Sex differences in knee laxity were menstrual cycle dependent, coinciding with significant elevations in estradiol levels. Females had greater laxity than males on day 5 of menses, days 3-5 near ovulation, days 1-4 of the early luteal phase and days 1, 2, 4 and 5 of the late luteal phases. Within females, knee laxity was greater on day 5 near ovulation compared to day 3 of menses, and days 1-3 of the early luteal phase compared to all days of menses and day 1 near ovulation. On average, differences observed between sexes were greater than those within females across their cycle. There were no differences in anterior knee stiffness between sexes or within females across days of the menstrual cycle.
为阐明激素对膝关节行为性别差异的影响，本研究对正常月经周期的女性与男性在整个女性月经周期中的血清激素水平、膝关节前侧松弛度（46N、89N和133N时的位移）及刚度（46 - 89N和89 - 133N时的力变化/位移变化的线性斜率）进行了比较。
22名女性在一个完整月经周期内每天进行测试，20名男性每周测试一次，共测试4周。将分别代表月经期、排卵前雌激素初升期、黄体早期和晚期激素环境的5天（共20天）与男性在其4次测试日获得的平均值进行比较。
膝关节松弛度的性别差异取决于月经周期，与雌二醇水平的显著升高一致。女性在月经期第5天、排卵前3 - 5天、黄体早期第1 - 4天以及黄体晚期第1、2、4和5天的松弛度大于男性。在女性中，排卵前第5天的膝关节松弛度大于月经期第3天，黄体早期第1 - 3天的膝关节松弛度大于月经期所有天数及排卵前第1天。平均而言，观察到的性别差异大于女性整个周期内的个体差异。月经周期各天中，男女之间以及女性个体之间的膝关节前侧刚度均无差异。
