Influence of Neck Flexion on Lumbar Curvature during Bridging Exercises

抄録

[Purpose] The purpose of our study was to analyze the influence of passive and active neck flexion on spinal curvatures during bridging exercises. [Subjects and Methods] In experiment 1, thirteen healthy male subjects were instructed to elevate their pelvises until the greater trochanter was in line with the acromion and the epicondylus lateralis femoris at 3 different positions of passive neck flexion: with the head placed on a flat surface, with the head on a 6-cm block and with the head on a 12-cm block. In experiment 2, eleven healthy male subjects were then asked to elevate the pelvis with maximal voluntary exertion in the following 4 different positions of active neck flexion: with the head rested on a flat surface, with the head held slightly above a flat surface, with the head held slightly above a 6-cm block, and with the head held slightly above a 12-cm block. While the subjects performed each bridging exercise, electromyography (EMG) and curvatures of the spine were measured. [Results] No significant differences were observed in the EMG activities of the muscles, but passive neck flexion significantly decreased lumbar lordosis during a bridging exercise with the head placed on a 12-cm block. Elevating the head slightly above a 12-cm block induces moderate contraction of the rectus abdominis and decreases the activity of the lumbar extensors, which significantly decreases lumbar lordosis during bridging. [Conclusion] The neck flexion should be considered when prescribing variations of a bridging exercise.