David O. Draper is Associate Professor, Coordinator of the Graduate Athletic Training Program, and Head Baseball Trainer at Brigham Young University, Provo, UT 84602.
J Athl Train. 1995 Oct;30(4):304-7.
Researchers have determined that when therapeutic ultrasound vigorously heats connective tissue, it can be effective in increasing extensibility of collagen affected by scar tissue. These findings give credence to the use of continuous thermal ultrasound to heat tissue before stretching, exercise, or friction massage in an effort to decrease joint contractures and increase range of motion. Before our investigation, it was not known how long following an ultrasound treatment the tissue will remain at a vigorous heating level (>3 degrees C). We conducted this study to determine the rate of temperature decay following 3 MHz ultrasound, in order to determine the time period of optimal stretching. Twenty subjects had a 23-gauge hypodermic needle microprobe inserted 1.2 cm deep into the medial aspect of their anesthetized triceps surae muscle. Subjects then received a 3 MHz ultrasound treatment at 1.5 W/cm(2) until the tissue temperature was increased at least 5 degrees C. The mean baseline temperature before each treatment was 33.8 +/- 1.3 degrees C, and it peaked at 39.1 +/- 1.2 degrees C from the ultrasound. Immediately following the treatment, we recorded the rate at which the temperature dropped at 30-second intervals. We ran a stepwise nonlinear regression analysis to predict temperature decay as a function of time following ultrasound treatment. We found a significant nonlinear relationship between time and temperature decay. The average time it took for the temperature to drop each degree as expressed in minutes and seconds was: 1 degrees C = 1:20; 2 degrees C = 3:22; 3 degrees C = 5:50; 4 degrees C = 9:13; 5 degrees C = 14:55; 5.3 degrees C = 18:00 (baseline). We conclude that under similar circumstances where the tissue temperature is raised 5 degrees C, stretching will be effective, on average, for 3.3 minutes following an ultrasound treatment. To increase this stretching window, we suggest that stretching be applied during and immediately after ultrasound application.
研究人员已经确定，当治疗性超声波剧烈加热结缔组织时，它可以有效地增加受疤痕组织影响的胶原蛋白的伸展性。这些发现为在拉伸、运动或摩擦按摩之前使用连续热超声加热组织提供了依据，以减少关节挛缩并增加运动范围。在我们的调查之前，尚不清楚在超声治疗后，组织将保持在剧烈加热水平（>3°C）多长时间。我们进行这项研究是为了确定 3MHz 超声治疗后温度下降的速度，以确定最佳拉伸时间。二十名受试者将 23 号皮下注射微探针插入其麻醉的三头肌内侧 1.2 厘米深。然后，受试者以 1.5W/cm² 的 3MHz 超声治疗，直到组织温度升高至少 5°C。每次治疗前的平均基线温度为 33.8±1.3°C，超声治疗后达到 39.1±1.2°C。治疗后立即以 30 秒的间隔记录温度下降的速度。我们进行了逐步非线性回归分析，以预测超声治疗后温度随时间的衰减。我们发现时间和温度衰减之间存在显著的非线性关系。温度每下降 1°C 所需的平均时间（以分钟和秒表示）为：1°C=1:20；2°C=3:22；3°C=5:50；4°C=9:13；5°C=14:55；5.3°C=18:00（基线）。我们的结论是，在组织温度升高 5°C 的类似情况下，超声治疗后平均 3.3 分钟内拉伸将有效。为了增加这个拉伸窗口，我们建议在超声应用期间和之后立即进行拉伸。
