Pamukoff Derek N, Pietrosimone Brian G, Ryan Eric D, Lee Dustin R, Blackburn J Troy
California State University, Fullerton.
University of North Carolina at Chapel Hill.
J Athl Train. 2017 May;52(5):422-428. doi: 10.4085/1062-6050-52.3.05. Epub 2017 Apr 18.
Individuals with anterior cruciate ligament reconstruction (ACLR) have quadriceps dysfunction that contributes to physical disability and posttraumatic knee osteoarthritis. Quadriceps function in the ACLR limb is commonly evaluated relative to the contralateral uninjured limb. Bilateral quadriceps dysfunction is common in individuals with ACLR, potentially biasing these evaluations.
To compare quadriceps function between individuals with ACLR and uninjured control participants.
Cross-sectional study.
Research laboratory.
Twenty individuals with unilateral ACLR (age = 21.1 ± 1.7 years, mass = 68.3 ± 14.9 kg, time since ACLR = 50.7 ± 21.3 months; females = 14; Tegner Score = 7.1 ± 0.3; 16 patellar tendon autografts, 3 hamstrings autografts, 1 allograft) matched to 20 control participants (age = 21.2 ± 1.2 years, mass = 67.9 ± 11.3 kg; females = 14; Tegner Score = 7.1 ± 0.4) on age, sex, body mass index, and Tegner Activity Scale.
MAIN OUTCOME MEASURE(S): Maximal voluntary isometric knee extension was performed on an isokinetic dynamometer. Peak torque (PT), rate of torque development (RTD), electromyographic (EMG) amplitude, central activation ratio (CAR), and hamstrings EMG amplitude were assessed during maximal voluntary isometric knee extension and compared between groups using independent-samples t tests. Relationships between hamstrings co-activation and quadriceps function were assessed using Pearson correlations.
Participants with anterior cruciate ligament reconstruction displayed lesser quadriceps PT (1.86 ± 0.74 versus 2.56 ± 0.37 Nm/kg, P = .001), RTD (39.4 ± 18.7 versus 52.9 ± 16.4 Nm/s/kg, P = .03), EMG amplitude (0.25 ± 0.12 versus 0.37 ± 0.26 mV, P = .04), and CAR (83.3% ± 11.1% versus 93.7% ± 3.2%, P = .002) and greater hamstrings co-activation (27.2% ± 12.8% versus 14.3% ± 3.7%, P < .001) compared with control participants. Correlations were found between hamstrings co-activation and PT (r = -0.39, P = .007), RTD (r = -0.30, P = .03), and EMG amplitude (r = -0.30, P = .03).
Individuals with ACLR possessed deficits in PT, RTD, and CAR compared with control participants. Peak torque is the net result of all agonist and antagonist activity, and lesser PT in individuals with ACLR is partially attributable to greater hamstrings co-activation.
前交叉韧带重建（ACLR）患者存在股四头肌功能障碍，这会导致身体残疾和创伤后膝关节骨关节炎。ACLR肢体的股四头肌功能通常相对于对侧未受伤肢体进行评估。双侧股四头肌功能障碍在ACLR患者中很常见，这可能会使这些评估产生偏差。
比较ACLR患者与未受伤对照参与者的股四头肌功能。
横断面研究。
研究实验室。
20名单侧ACLR患者（年龄=21.1±1.7岁，体重=68.3±14.9kg，ACLR后时间=50.7±21.3个月；女性14名；Tegner评分=7.1±0.3；16例髌腱自体移植，3例腘绳肌自体移植，1例同种异体移植）与20名对照参与者（年龄=21.2±1.2岁，体重=67.9±11.3kg；女性14名；Tegner评分=7. –1±0.4）在年龄、性别、体重指数和Tegner活动量表方面进行匹配。
在等速测力计上进行最大自主等长膝关节伸展。在最大自主等长膝关节伸展期间评估峰值扭矩（PT）、扭矩发展速率（RTD）、肌电图（EMG）幅度、中枢激活率（CAR）和腘绳肌EMG幅度，并使用独立样本t检验在组间进行比较。使用Pearson相关性评估腘绳肌共同激活与股四头肌功能之间的关系。
与对照参与者相比，前交叉韧带重建患者的股四头肌PT（1.86±0.74对2.56±0.37 Nm/kg，P = 0.001）、RTD（39.4±18.7对52.9±16.4 Nm/s/kg，P = 0.03）、EMG幅度（0.25±0.12对0.37±0.26 mV，P = 0.04）和CAR（83.3%±11.1%对93.7%±3.2%，P = 0.002）较低，腘绳肌共同激活较高（27.2%±12.8%对14.3%±3.7%，P < 0.001）。发现腘绳肌共同激活与PT（r = -0.39，P = 0.007）、RTD（r = -0.30，P = 0.03）和EMG幅度（r = -0.30，P = 0.03）之间存在相关性。
与对照参与者相比，ACLR患者在PT、RTD和CAR方面存在缺陷。峰值扭矩是所有 agonist和 antagonist活动的净结果，ACLR患者较低的PT部分归因于较高的腘绳肌共同激活。
