Lehman Gregory J, Lennon Duane, Tresidder Brian, Rayfield Ben, Poschar Michael
Department of Graduate Studies and Research, Canadian Memorial Chiropractic College, 1900 Bayview Ave, Toronto, ON, Canada.
BMC Musculoskelet Disord. 2004 Feb 10;5:3. doi: 10.1186/1471-2474-5-3.
The prone leg extension (PLE) is a clinical test used to evaluate the function of the lumbopelvis. It has been theorized that a normal and consistent pattern of muscle activation exists. Previous research has found two contradictory patterns of muscle activation during PLE in normal individuals. One study shows an almost simultaneous activation of the lower erector spinae and hamstring muscle group with a delayed activation of the gluteus maximus, while the second describes the order of activation being ipsilateral erector spinae (to the leg being extended), hamstrings, contralateral erector spinae and gluteus maximus. Due to the different conclusions from these two studies and the lack of quantified muscle onset times, expressed in absolute time this study attempted to quantify the muscle onset times (in milliseconds) during the prone leg extension, while noting if a consistent order of activation exists and whether a timing relationship also exists between the gluteus maximus and contralateral latissimus dorsi.
10 asymptomatic males (Average height: 175.2 cm (SD 6.5), Average Weight 75.9 kg (SD 6.5), Average Age: 27.1(SD 1.28)) and 4 asymptomatic females (Average height 164.5 (SD 2.9), weight: 56.2 (SD 8.9), Average Age: 25 (SD 1)) performed the prone leg extension task while the myoelectric signal was recorded from the bilateral lower erector spinae, gluteus maximus and hamstring muscle groups. Activation onsets were determined from the rectified EMG signal relative to the onset of the hamstrings muscle group.
No consistent recruitment patterns were detected for prone leg extension among the hamstring muscle group and the erector spinae. However, a consistent delay in the Gluteus Maximus firing of approximately 370 ms after the first muscle activated was found. Five out of 14 asymptomatic subjects showed a delay in gluteus maximus firing exceeding the average delay found in previous research of subjects considered to have a dysfunctional firing pattern.
A consistent pattern of activation was not found. Variability was seen across subjects. These findings suggest the PLE is not sufficient for a diagnostic test due to the notable physiological variation. An overlap between normal and potentially abnormal activation patterns may exist.
俯卧腿伸展（PLE）是一种用于评估腰骨盆功能的临床测试。理论上认为存在正常且一致的肌肉激活模式。先前的研究发现，正常个体在进行俯卧腿伸展时存在两种相互矛盾的肌肉激活模式。一项研究表明，下竖脊肌和腘绳肌群几乎同时激活，而臀大肌激活延迟；另一项研究则描述激活顺序为同侧竖脊肌（与伸展的腿同侧）、腘绳肌、对侧竖脊肌和臀大肌。由于这两项研究得出了不同结论，且缺乏以绝对时间表示的肌肉起始时间量化，本研究试图量化俯卧腿伸展过程中的肌肉起始时间（以毫秒为单位），同时记录是否存在一致的激活顺序，以及臀大肌和对侧背阔肌之间是否也存在时间关系。
10名无症状男性（平均身高：175.2厘米（标准差6.5），平均体重75.9千克（标准差6.5），平均年龄：27.1岁（标准差1.28））和4名无症状女性（平均身高164.5厘米（标准差2.9），体重：56.2千克（标准差8.9），平均年龄：25岁（标准差1））进行俯卧腿伸展任务，同时记录双侧下竖脊肌、臀大肌和腘绳肌群的肌电信号。根据整流后的肌电信号相对于腘绳肌群起始点来确定激活起始点。
在腘绳肌群和竖脊肌中未检测到俯卧腿伸展的一致募集模式。然而，发现臀大肌在第一个肌肉激活后约370毫秒出现一致的延迟放电。14名无症状受试者中有5名的臀大肌放电延迟超过了先前研究中被认为存在功能失调放电模式的受试者的平均延迟时间。
未发现一致的激活模式。受试者之间存在变异性。这些发现表明，由于明显的生理变异，俯卧腿伸展不足以作为一种诊断测试。正常和潜在异常激活模式之间可能存在重叠。
