Neck strength and EMG activity in fighter pilots with episodic neck pain

INTRODUCTION: Neck pain is common in fighter pilots due to repeated exposure to high +Gz loads, but studies comparing neck function in symptomatic and healthy fighter pilots are lacking. This study compared neck strength and EMG activity during maximal isometric contractions in a sitting position in the sagittal and coronal planes in neck pain (SP), asymptomatic fighter pilots (AP), and healthy, male, non-pilot subjects (NPS). METHODS: There were 9 SP, 10 AP, and 8 NPS, all males, who performed maximal isometric neck contractions on a specific dynamometer. Surface EMG activity was recorded bilaterally over the sternocleidomastoid and paraspinal muscles. EMG amplitude during side bending was normalized to that measured in the sagittal plane. RESULTS: SP exhibited lower side-bending strength than AP (17-19%, P < 0.05). In addition, SP and NPS exhibited lower left side-bending-to-extension torque ratios (20% and 14%, respectively, P < 0.05) than AP. Similar activation level of neck flexors and extensors during side bending was found in SP and AP, whereas EMG activity of the extensors was higher than the flexors in NPS (+48%, P < 0.05). In addition, antagonistic EMG activity was higher in AP compared to NPS (26% vs. 41%, respectively, P < 0.05). CONCLUSION: Our results suggest altered muscle function in SP compared with AP in the coronal but not in the sagittal plane. Further, AP appeared to be more efficient in the coronal plane with reference to neck extension than NPS, suggesting that some adaptations occurred due to flight exposure. These findings may have clinical implications for the management and the follow-up of neck pain in fighter pilots.