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Comparison of Restraint Systems for Pelvic Stabilization


    This study examined two distinct restraint systems designed to isolate the lumbar extensors, both proving to be effective methods for enhancing lower back strength. The two different restraint systems are used through the pelvic stabilization by preventing movements in the lower part of your body while seated. Restraints are located on the knees and on the bottom of the feet. The goal of the study is to see how the restraint systems can influence lumbar extension strength and the shape of isometric lumbar extension strength curve.


    In the research titled “Comparison of Two Restraint Systems for Pelvic Stabilization during Isometric Lumbar Extension Strength Testing,” the study comprised a sample of fifteen men (with an average age of 37 years, height ranging from 177.7 ± 5.3 cm, and weight averaging 61.4 ± 10.9 kg) and six women (with an average age of 43 years, height ranging from 170 ± 7.9 cm, and weight averaging 61.4 ± 10.9 kg). Each participant underwent testing at seven different positions spanning a 72-degree range of motion using both restraint systems. The study aimed to examine the impact of lumbar extension strength by analyzing the effect and shape of the isometric lumbar extension strength curve.

    Each participant in the study underwent two distinct isometric lumbar extension strength evaluations while seated. Utilizing a MedX machine, extension torque was assessed at increments of 72, 60, 48, 36, 24, 12, and 0 degrees of lumbar flexion. Throughout each test, pelvic stability was maintained by securing the femurs downward and backward into the pelvis using a restraint pad. The variance between the two tests lies in the points of pressure application by the machine: in one, pressure is exerted on the knees, while in the other, it’s on the feet. During knee-pressure tests, the lower legs were positioned at a 120-degree angle, while in foot-restrained tests, the angle was set at 60 degrees. To mitigate muscle fatigue and soreness, the two tests with different restraints were conducted with a minimum gap of 72 hours but no longer than one week.

    In this study, two restraint systems were utilized, varying based on the lower leg position and the degree of applied force. These systems diverged slightly due to discrepancies in weight loads and positioning. The foot restraint system proved more efficient in pelvis restriction, as evidenced by the absence of pelvic rotation post-test. Additionally, the lumbar strength curve exhibited a flatter trajectory with the foot restraint system, indicating enhanced lumbar strength during motion. It is worth noting that knee restraint systems lose validity when tested with an alternative restraint system.