Hart Joseph M, Fritz Julie M, Kerrigan D Casey, Saliba Ethan N, Gansneder Bruce M, Ingersoll Christopher D
University of Virginia, Department of Orthopaedic Surgery, Charlottesville, VA 22908-0159, USA.
J Athl Train. 2006 Jan-Mar;41(1):79-86.
Although poor paraspinal muscle endurance has been associated with less quadriceps activation (QA) in persons with a history of low back pain, no authors have addressed the acute neuromuscular response after lumbar paraspinal fatiguing exercise.
To compare QA after lumbar paraspinal fatiguing exercise in healthy individuals and those with a history of low back pain.
A 2 x 4 repeated-measures, time-series design.
Exercise and Sport Injury Laboratory.
Sixteen volunteers participated (9 males, 7 females; 8 controls and 8 with a history of low back pain; age = 24.1 +/- 3.1 years, height = 173.4 +/- 7.1 cm, mass = 72.4 +/- 12.1 kg).
INTERVENTION(S): Subjects performed 3 sets of isometric lumbar paraspinal fatiguing muscle contractions. Exercise sets continued until the desired shift in lumbar paraspinal electromyographic median power frequency was observed. Baseline QA was compared with QA after each exercise set.
MAIN OUTCOME MEASURE(S): An electric burst was superimposed while subjects performed a maximal quadriceps contraction. We used the central activation ratio to calculate QA = (F(MVIC)/[F(MVIC) + F(Burst)])* 100, where F = force and MVIC = maximal voluntary isometric contractions. Quadriceps electromyographic activity was collected at the same time as QA measurements to permit calculation of median frequency during MVIC.
Average QA decreased from baseline (87.4% +/- 8.2%) after the first (84.5% +/- 10.5%), second (81.4% +/- 11.0%), and third (78.2% +/- 12.7%) fatiguing exercise sets. On average, the group with a history of low back pain showed significantly more QA than controls. No significant change in quadriceps median frequency was noted during the quadriceps MVICs.
The quadriceps muscle group was inhibited after lumbar paraspinal fatiguing exercise in the absence of quadriceps fatigue. This effect may be different for people with a history of low back pain compared with healthy controls.
尽管在有腰痛病史的人群中，脊柱旁肌肉耐力差与股四头肌激活（QA）减少有关，但尚无作者探讨腰椎脊柱旁疲劳运动后的急性神经肌肉反应。
比较健康个体和有腰痛病史的个体在腰椎脊柱旁疲劳运动后的股四头肌激活情况。
2×4重复测量、时间序列设计。
运动与运动损伤实验室。
16名志愿者参与（9名男性，7名女性；8名对照组和8名有腰痛病史者；年龄=24.1±3.1岁，身高=173.4±7.1厘米，体重=72.4±12.1千克）。
受试者进行3组等长腰椎脊柱旁疲劳肌肉收缩。运动组持续进行，直到观察到腰椎脊柱旁肌电图中位功率频率出现预期变化。将基线股四头肌激活情况与每组运动后的股四头肌激活情况进行比较。
在受试者进行最大股四头肌收缩时叠加一个电脉冲。我们使用中枢激活率来计算股四头肌激活情况=（F（MVIC）/[F（MVIC）+F（电脉冲）]）×100，其中F=力量，MVIC=最大自主等长收缩。在测量股四头肌激活情况的同时收集股四头肌肌电图活动，以便计算最大自主等长收缩期间的中位频率。
在进行第一组（84.5%±10.5%）、第二组（81.4%±11.0%）和第三组（78.2%±12.7%）疲劳运动组后，平均股四头肌激活情况从基线（87.4%±8.2%）下降。平均而言，有腰痛病史的组比对照组的股四头肌激活情况明显更多。在股四头肌最大自主等长收缩期间，股四头肌中位频率没有显著变化。
在没有股四头肌疲劳的情况下，腰椎脊柱旁疲劳运动后股四头肌肌群受到抑制。与健康对照组相比，这种效应在有腰痛病史的人群中可能有所不同。
