Flevas Dimitrios A, Bernard Manfred, Ristanis Stavros, Moraiti Constantina, Georgoulis Anastasios D, Pappas Evangelos
Orthopaedic Sports Medicine Center, Department of Orthopaedic Surgery, University of Ioannina, Ioannina, Greece.
Department of Orthopaedic Surgery, Klinik Sanssouci Potsdam - Berlin, Berlin, Germany.
Knee Surg Sports Traumatol Arthrosc. 2017 Jun;25(6):1903-1907. doi: 10.1007/s00167-016-4243-6. Epub 2016 Jul 11.
The purpose of this study was to investigate the effect of chronic ankle instability (CAI) on electromechanical delay times (EMD) before and after fatigue. Understanding the mechanisms that contribute to CAI is essential for the development of effective rehabilitation programmes. It was hypothesized that patients with CAI will demonstrate prolonged EMD times compared to healthy subjects and that fatigue will cause greater increases in EMD times in the CAI group.
Twenty-one male volunteers participated in the study providing data on 16 ankles with CAI and 26 with no history of ankle injury. EMD was measured on an isokinetic dynamometer. Measurements were taken with the ankle in neutral (0°) and at 30° of inversion. All subjects followed an isokinetic fatigue protocol until eversion torque fell below 50 % of initial torque for three consecutive repetitions. A 2 × 2 × 2 ANOVA was used to calculate the effect of ankle status (CAI vs. healthy), fatigue, angle (0° vs. 30°) and their interactions on EMD.
Fatigue caused a significant increase on EMD [non-fatigued: 122(29)ms vs. fatigue 155(54)ms; p < 0.001]. EMD times were shorter at 30° of inversion compared to neutral [neutral: 145(39)ms vs. 30° of inversion: 132(40)ms, p = 0.015]. An interaction effect for ankle status and angle was found (p = 0.026) with CAI ankles demonstrating longer EMD [CAI: 156(45)ms vs. healthy: 133(40)ms] in neutral but not at 30° of inversion [CAI: 133(46)ms vs. 132(33)ms].
Patients with CAI had longer EMD times in neutral, but not when the ankle was placed in inversion. This suggests that rehabilitation programmes may be more effective when retraining occurs with the ankle in neutral position. It is likely that low EMD times prevent ankle acceleration at the beginning of the mechanism of injury, but they are less important when the ankle has already inverted at 30°. Both CAI and healthy subjects demonstrated longer EMD after fatigue, emphasizing the importance of proper conditioning in the prevention of delayed peroneal response and subsequent ankle injury. Improving resistance to fatigue of the peroneals may prove to be an effective prevention tool of ankle sprain recurrence in patients with CAI.
III.
本研究旨在调查慢性踝关节不稳（CAI）对疲劳前后机电延迟时间（EMD）的影响。了解导致CAI的机制对于制定有效的康复计划至关重要。研究假设，与健康受试者相比，CAI患者的EMD时间会延长，并且疲劳会使CAI组的EMD时间增加得更多。
21名男性志愿者参与了本研究，提供了16个患有CAI的踝关节和26个无踝关节损伤史的踝关节的数据。使用等速测力计测量EMD。在踝关节处于中立位（0°）和内翻30°时进行测量。所有受试者均遵循等速疲劳方案，直到外翻扭矩连续三次重复低于初始扭矩的50%。使用2×2×2方差分析来计算踝关节状态（CAI与健康）、疲劳、角度（0°与30°）及其相互作用对EMD的影响。
疲劳导致EMD显著增加[未疲劳：122（29）毫秒 vs. 疲劳：155（54）毫秒；p < 0.001]。与中立位相比，内翻30°时的EMD时间更短[中立位：145（39）毫秒 vs. 内翻30°：132（40）毫秒，p = 0.015]。发现踝关节状态和角度之间存在交互作用（p = 0.026），CAI踝关节在中立位时的EMD更长[CAI：156（45）毫秒 vs. 健康：133（40）毫秒]，但在内翻30°时并非如此[CAI：133（46）毫秒 vs. 132（33）毫秒]。
CAI患者在中立位时的EMD时间更长，但踝关节内翻时并非如此。这表明当在中立位对踝关节进行再训练时，康复计划可能更有效。很可能低EMD时间会在损伤机制开始时阻止踝关节加速，但当踝关节已经内翻30°时，它们的重要性就降低了。CAI患者和健康受试者在疲劳后的EMD都更长，这强调了适当的体能训练在预防腓骨肌延迟反应和随后的踝关节损伤中的重要性。提高腓骨肌的抗疲劳能力可能被证明是预防CAI患者踝关节扭伤复发的有效工具。
III级。
