University of Southern Denmark Self-administered physical exercise training as treatment of neck and shoulder pain among military helicopter pilots and crew a randomized controlled trial

Background: Neck pain is frequent among military helicopter pilots and crew-members, and pain may influence individual health and work performance. The aim of this study was to examine if an exercise intervention could reduce neck pain among helicopter pilots and crew-members. Methods: Thirty-one pilots and thirty-eight crew-members were randomized to either an exercise-training-group (n = 35) or a reference-group (n = 34). The exercise-training-group received 20-weeks of specific neck/shoulder training. The reference-group received no training. Primary outcome: Intensity of neck pain previous 3-months (scale 0-10). Secondary outcomes: additional neck/shoulder pain intensity variables and pressure-pain-threshold in the trapezius muscle (TRA) and upper-neck-extensor muscles (UNE). Regular training adherence was defined as ≥1 training session a week. Statistical analyses performed were intention-to-treat and per-protocol. Students t-test was performed (p < 0.05). Results: Intensity of neck pain previous 3-months at baseline was: 2.2 ± 1.8 and previous 7-days: 1.0 ± 1.5, and pressure-pain-threshold in TRA and UNE (right/left) was in kPa: 424 ± 187 / 434 ± 188 and 345 ± 157 / 371 ± 170 in the exercise-training-group, and 416 ± 177 / 405 ± 163 and 334 ± 147 / 335 ± 163 in the reference-group, with no differences between groups. Intention-to-treat-analysis revealed no significant between-group-differences in neck pain intensity and pressure-pain-threshold. Between-group-differences, including participants who trained regularly (n = 10) were also non-significant. Within-group-changes were significant among participants with regular training adherence in the exercise-training-group regarding intensity of neck pain previous 3-months (from 2.2 ± 0.6 to 1.3 ± 1.3, p = 0.019). Likewise, within the whole exercise-training-group, neck pain previous 7-days decreased (from 1.0 ± 1.4 to 0.6 ± 1.1, p = 0.024). Additional within-group-changes regarding pressure-pain-threshold in kPa were for the reference-group a reduction in TRA and UNE (right/left) to: 342 ± 143 / 332 ± 154 and 295 ± 116 / 292 ± 121 implying increased pain sensitivity, while for the exercise-training-group only a reduction in left TRA was seen: 311 ± 113. Conclusions: The exercise intervention did not reduce neck pain among helicopter pilots and crew-members as no significant between-group-differences were found. However, some trends were demonstrated as some neck pain intensity and sensitivity improved more within the exercise-training-group but not within the reference-group. The lack of effect may be due to low adherence since only ~ 1/3 of subjects in the exercise-training-group engaged in regular training which may be due to the self-administration of the training. (Continued on next page) * Correspondence: mike_ster@hotmail.com Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark Full list of author information is available at the end of the article © The Author(s). 2017 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. Murray et al. BMC Musculoskeletal Disorders (2017) 18:147 DOI 10.1186/s12891-017-1507-3