Author(s): HONKANEN, T., VAARA, J.P., MATTIILA, V., JANHUNEN, M., SOVELIUS, R., KYRÖLÄINEN, H., Institution: NATIONAL DEFENCE UNIVERSITY, Country: FINLAND, Abstract-ID: 1373

INTRODUCTION:
Fast jet pilots are repetitively exposed to high Gz-forces and abrupt head maneuvering which can cause neck pain, loss of flight years and possible disability. Strong neck muscles may decrease the risk of injury and disability. However, there is no reports in the literature about standard neck muscle testing regimen in any air forces. The purpose of this study was to examine the intra- and inter-tester reliability of a commercial force gauge attached to a pilot’s helmet for measuring isometric neck muscle strength.
METHODS:
A total of 41 volunteer Air Force Academy cadets were recruited for this study. All subjects performed two measurements sessions for intra-tester reliability, whereas 31 subjects participated for the third session for inter-tester reliability. Peak force values were measured in all four directions (flexion, extension, lateral flexions). Best of three attempts in each direction was chosen. Three measurements were performed in three different days. Self-reported delayed muscle soreness (DOMS) and neck pain was assessed with Visual Analogic Scale (VAS) before and after each measurement session. ICC values were calculated to assess both intra- and inter-tester reliability.
RESULTS:
The overall inter-tester reliability was good (ICC = 0.79 – 0.90), whereas the intra-tester reliability varied from moderate to good (ICC = 0.58 – 0.84). In both intra- and inter-tester reliability, the flexion test had good (ICC 0.84 – 0.89) and the lateral flexion tests results moderate to good (ICC 0.73 - 0.90) reliability. Whereas the extension test had lowest reliability in both intra- (ICC 0.58) and inter-rater (ICC 0.79) tests. The average VAS -score (in 1 to 100 scale) prior the second measurement session was 16/100 in DOMS and 0/100 in pain.
CONCLUSION:
The present study observed good reliability in isometric neck muscle strength test in the flexion and lateral flexions. In addition, DOMS and pain questionnaires indicate that isometric neck strength could be measured safely and without interrupting other duties, i.e. flying. In conclusion, the helmet-attached force gauge is reliable and clinically applicable valid method to evaluate isometric neck strength. However, further development of testing procedure and equipment have to be done to increase the reliability of test in the extension direction.