Proper lumbar stabilization has has demonstrated effectiveness in 80% of patients. MRI results have been shown to identify active muscles immediately following exercise by the fluid shift out of the vascular bed into active muscle mass. The purpose of this study was to use MRI testing to display the active muscles during two lumbar exercises and to compare the primary muscles involved in these exercises.
20 healthy subjects completed one set of exercise to fatigue on the MedX Lumbar Extension Machine and a 45-degree Roman Chair using slow controlled repetitions. MRI was used to analyze the exercise response of four muscles, multifidus, erector spinae, quadratus, and psoas. Scans were performed before and immediately following exercise. Results showed that the overall signal intensity increase in active muscles for MedX was 41.9% and Roman Chair was 29.6%. The study concluded that based on activation patterns, Roman Chair uses the same muscles as MedX, but to a lesser degree. Both machines are appropriate for specific training of the lumbar extensors, however, MedX is the preferred exercise due to the greater lumbar muscle activation.
Keywords: Lumbar, MedX Lumbar Extension Machine, Roman Chair, MRI, activation patterns