Date Published: September 25, 2018
Publisher: Public Library of Science
Author(s): Matthias Tegern, Ulrika Aasa, Björn O. Äng, Karin Harms-Ringdahl, Helena Larsson, Antal Nógrádi.
Strategies are needed to mitigate the high rates and related risks of musculoskeletal complaints and injuries (MSCI) in the military aviator community. Previous work on Swedish Armed Forces (SwAF) soldiers have shown that proper screening methods have been successful in reducing early discharge from military training. Research has pointed at the importance of optimal spinal movement control in military aviators. The aim of this work was to investigate the inter-rater and test-retest reliability of a battery of clinical tests for evaluating movement control in the neck, shoulders, thoracic, lumbar, and hip regions in a population of SwAF military personnel. Inter-rater and test-retest reliability of 15 movement control tests were assessed by crude and prevalence-adjusted kappa coefficient. The study included 37 (inter-rater) and 45 (test-retest) SwAF personnel and was performed with two physiotherapists simultaneously observing and rating the movements on the first occasion and repeated with one physiotherapist on the second occasion. For inter-rater reliability, the kappa coefficient ranged from .19 to .95. Seven tests showed substantial to almost perfect agreement (kappa > .60). With the adjusted kappa, three more tests reached the level of substantial agreement. The corresponding values for test-retest reliability ranged from .26 to .65. Substantial agreement was attained for two tests, three with adjusted kappa. The following tests can reliably be used when screening for biomechanically less advantageous movement patters in military aviators: Shoulder flexion, and rotation, Neck flexion in sitting and supine, Neck extension and rotation in sitting, Pelvic tilt, Forward lean and Single and Double knee extension tests. Grading criteria for tests in supine and quadruped positions need to be further elaborated.
Musculoskeletal pain is the main cause of disability in most countries . In the general population, the low back  and the neck  are the most commonly affected regions. This is also true for military aviators, including fighter [4–6] and helicopter [7, 8] pilots as well as helicopter cabin crew . In active military ground units, the highest prevalence of musculoskeletal pain is in the low back and the lower extremities [10–12]. Musculoskeletal injuries cause a higher rate of lost duty days than illness. When soldiers have regular episodes of musculoskeletal complaints, this might affect a unit’s readiness . Prevention of musculoskeletal injuries is thus important.
Fig 1 shows that many of the military personnel reported MSCI; the highest one-year prevalence was 32.4% and 37.8% for MSCI in the lumbar spine for both the inter-rater and the test-retest study groups, respectively (the corresponding MSCI at present was 21.6% and 17.8%, respectively). For any (one or more region) MSCI the one year prevalence was 64.4% and 64.9%, and for MSCI at present the prevalence was 44.4% and 43.2%, respectively. The secondary analyses showed that there were no significant differences between the number of passed tests between participants with ongoing or previous MSCI and those without MSCI. (7) Further, there was no significant difference in the number of tests with a changed outcome (e.g. optimal on test 1 but non-optimal on test 2) from test 1 to test 2 between participants with and without MSCI, respectively. The within-group McNemar test showed no significant difference on any movement control test from test 1 to test 2, indicating no learning effect among the participants.
This is the first study to investigate inter-rater and test-retest reliability of movement control tests for several body regions, in a military population. The inter-rater reliability for seven of the 15 tests reached a level representing substantial to almost perfect agreement (kappa = .64–.95). With PABAK, three more tests reached the level of substantial agreement (kappa > .60). The test-retest results showed generally lower kappa coefficients than the inter-rater values, and two tests (three when PABAK was calculated) showed substantial agreement (test-retest kappa = .63–.65). These two tests also had acceptable results on inter-rater reliability. Namely, the Single knee extension (right side) had an inter-rater kappa of .65 and the Pelvic tilt test had a moderate inter-rater kappa of .44, but a substantial PABAK of .78. The third test was Neck rotation (right side) had an inter-rater kappa of .64. The difference between PABAK and unadjusted kappa coefficients was due to an unequal prevalence of passed/failed results on these tests.
In a military population, visual observations of movement control tests for neck and shoulder in sitting and standing, together with tests for thoracic, lumbar, and hip regions in sitting, could reliably be evaluated at the same occasion by two experienced PTs in this study. However, grading criteria for tests in supine and quadruped positions need to be further elaborated in the evaluation of movement control tests and factors affecting the lower test-retest reliability needs to be studied further.