Faculty of Physical Education and Sport Sciences, Aristotle University of Thessaloniki, Thessaloniki, Greece.
Exercise is Medicine, Aspetar Orthopedic Sport Medicine Hospital, Doha, Qatar.
J Strength Cond Res. 2018 Feb;32(2):578-586. doi: 10.1519/JSC.0000000000002311.
Xenofondos, A, Bassa, E, Vrabas, IS, Kotzamanidis, C, and Patikas, D. Muscle twitch torque during two different in volume isometric exercise protocols: fatigue effects on postactivation potentiation. J Strength Cond Res 32(2): 578-586, 2018-The purpose of this study was to quantify the effect of the contraction duration of 2 isometric exercise protocols on the postactivation potentiation of 14 well-trained men (age: 22.6 ± 2.8 years, height: 180.3 ± 5.9 cm, and body mass: 72.3 ± 37.9 kg). The protocols consisted of 4 × 6 maximal plantar flexions, of 3-second (P3) or 6-second (P6) duration, performed in random order, with a 2-minute and 15-second intervals between the sets and repetitions, respectively. The torque during maximal isometric voluntary contraction (MIVC), the peak twitch torque (TT), and the rate of torque development (RTD) after each MIVC were analyzed for the first and the last trial of each set, the average of all trials of each set, and the trials within each set that had the highest peak TT. The MIVC had an overall greater reduction during P6 compared with P3 (P3: -4.6 ± 2.3 vs. P6: -16.0 ± 1.9%). P6 showed higher potentiation in TT during the initial repetitions of the first 2 sets (p < 0.05) in contrast to the P3, which revealed a lower potentiation but for a longer period along the exercise session. However, both protocols had on average the same potential for potentiation (P3: 81.6 ± 6.1 vs. P6: 79.8 ± 6.3%). The twitch RTD presented no systematic difference between the 2 protocols (p > 0.05). These data demonstrate the dependence of the TT potentiation on the conditioning stimulus and verify the cumulative effect of potentiation, suggesting the implementation of longer contractions to achieve maximal but temporal TT potentiation and shorter contractions for less variable but prolonged potentiation.
Xenofondos、A、Bassa、E、Vrabas、IS、Kotzamanidis、C 和 Patikas、D. 两种不同等长向心运动方案下肌肉抽搐扭矩：疲劳对激活后增强的影响。J 力量与体能研究 32(2):578-586,2018.本研究的目的是量化 2 种等长运动方案的收缩持续时间对 14 名训练有素的男性（年龄：22.6±2.8 岁，身高：180.3±5.9cm，体重：72.3±37.9kg）激活后增强的影响。方案由 4×6 次 3 秒（P3）或 6 秒（P6）的最大足底屈肌收缩组成，以随机顺序进行，组间和重复之间分别间隔 2 分钟 15 秒。在每组的第一次和最后一次试验中，分析了最大等长随意收缩（MIVC）期间的扭矩、最大抽搐扭矩（TT）和扭矩发展率（RTD），以及每组所有试验的平均值，以及每组中 TT 峰值最高的试验。与 P3 相比，P6 期间 MIVC 的总体下降更大（P3：-4.6±2.3 对比 P6：-16.0±1.9%）。与 P3 相比，P6 在最初 2 组的前几次重复中 TT 表现出更高的增强（p<0.05），而 P3 则表现出较低的增强，但在运动过程中持续时间较长。然而，两种方案的增强潜力平均相同（P3：81.6±6.1 对比 P6：79.8±6.3%）。2 种方案之间的 RTD 无明显差异（p>0.05）。这些数据表明 TT 增强依赖于条件刺激，并验证了增强的累积效应，建议采用更长的收缩来实现最大但时间短暂的 TT 增强，采用更短的收缩来实现变化较小但持续时间较长的增强。
