Kuenze Christopher M, Hertel Jay, Hart Joseph M
Department of Kinesiology and Sport Sciences, University of Miami, Coral Gables, FL;
J Athl Train. 2014 Nov-Dec;49(6):740-6. doi: 10.4085/1062-6050-49.3.46.
Sex differences in lower extremity neuromuscular function have been reported after anterior cruciate ligament reconstruction (ACLR). Research evidence supports different levels of fatigability in men and women and between patients with ACLR and healthy controls. The influence of sex on the response to continuous exercise in patients with ACLR is not clear.
To compare quadriceps neuromuscular function after exercise between men and women with ACLR.
Descriptive laboratory study.
Laboratory.
Twenty-six active volunteers (13 men [50%]: age = 24.1 ± 4.4 years, height = 179.1 ± 9.8 cm, mass = 80.1 ± 9.4 kg, months since surgery = 43.5 ± 37.0; 13 women [50%]: age = 24.2 ± 5.6 years, height = 163.0 ± 5.9 cm, mass = 62.3 ± 8.3 kg, months since surgery = 45.8 ± 42.7) with a history of unilateral primary ACLR at least 6 months earlier.
INTERVENTION(S): Thirty minutes of continuous exercise comprising 5 separate 6-minute cycles, including 5 minutes of uphill walking and 1 minute of body-weight squatting and step-ups.
MAIN OUTCOME MEASURE(S): Normalized knee-extension maximal voluntary isometric contraction torque, quadriceps superimposed-burst torque, and quadriceps central activation ratio before and after exercise. We performed separate 2 (sex: men, women) × 2 (time: preexercise, postexercise) repeated-measures analyses of variance for the 3 variables. Separate, independent-samples t tests were calculated to compare preexercise with postexercise change in all dependent variables between sexes.
A significant group-by-time interaction was present for knee-extension torque (P = .04). The percentage reduction in knee-extension maximal voluntary isometric contraction torque (men = 1.94%, women = -10.32%; P = .02) and quadriceps central activation ratio (men = -1.45%, women = -8.69%; P = .03) experienced by men was less than that observed in women.
In the presence of quadriceps dysfunction, female participants experienced greater-magnitude reductions in quadriceps function after 30 minutes of exercise than male participants. This indicates a reduced ability to absorb knee-joint loads, which may have significant implications for reinjury and joint osteoarthritis in women after ACLR.
前交叉韧带重建术（ACLR）后，下肢神经肌肉功能存在性别差异。研究证据支持男性和女性以及ACL重建患者与健康对照者之间存在不同程度的疲劳性。性别对ACLR患者持续运动反应的影响尚不清楚。
比较ACLR男性和女性运动后股四头肌神经肌肉功能。
描述性实验室研究。
实验室。
26名活跃志愿者（13名男性[50%]：年龄=24.1±4.4岁，身高=179.1±9.8厘米，体重=80.1±9.4千克，术后月数=43.5±37.0；13名女性[50%]：年龄=24.2±5.6岁，身高=163.0±5.9厘米，体重=62.3±8.3千克，术后月数=45.8±42.7），均有至少6个月前单侧原发性ACLR病史。
30分钟的持续运动，包括5个单独的6分钟周期，其中包括5分钟上坡行走以及1分钟体重深蹲和上台阶。
运动前后的标准化膝关节伸展最大自主等长收缩扭矩、股四头肌叠加爆发扭矩和股四头肌中枢激活率。我们对这3个变量分别进行了2（性别：男性、女性）×2（时间：运动前、运动后）重复测量方差分析。计算独立样本t检验以比较性别之间所有因变量运动前与运动后变化。
膝关节伸展扭矩存在显著的组×时间交互作用（P = 0.04）。男性膝关节伸展最大自主等长收缩扭矩降低百分比（男性=1.94%，女性=-10.32%；P = 0.02）和股四头肌中枢激活率降低百分比（男性=-1.45%，女性=-8.69%；P = 0.03）低于女性。
在股四头肌功能障碍的情况下，女性参与者在30分钟运动后股四头肌功能下降幅度大于男性参与者。这表明女性吸收膝关节负荷的能力降低，这可能对ACLR术后女性再次受伤和关节骨关节炎具有重要影响。
