The effects of 12 weeks of functional strength training on muscle strength, volume and activity upon exposure to elevated Gz forces in high-performance aircraft personnel

Abstract

Background Technological advancements in modern military and acrobatic jet planes have resulted in extraordinary psychophysiological loads being exerted upon flying personnel, including inducing neck and back pain. The purpose of this study was to examine the effects of 12 weeks of functional strength training on 1) the volume and strength of the neck and shoulder muscles and 2) muscular activity upon exposure to helmets of different masses and elevated Gz forces in a long-arm centrifuge in high-performance aircraft personnel. Methods Eighteen participants underwent 12 weeks of functional strength training (n = 12) or the control protocol (n = 6) without additional strength training. Pre- and post-intervention tests included evaluations of isometric strength of the head extensor muscles, flexion, and lateral flexion and rotation, as well as magnetic resonance imaging (MRI) to measure the volume of the m. sternocleidomastoideus, m. trapezius, and deep neck muscles. Furthermore, during a long-arm centrifuge (+ 1.4 and + 3 Gz) protocol, the muscular activity levels of the m. sternocleidomastoideus, m. trapezius and m. erector spinae muscles were assessed without a flight helmet, with a helmet, and with a helmet and night vision goggles. Each participant’s perception of muscular strain was noted immediately after the long-arm centrifuge protocol. Results The maximal isometric strength in all exercises and muscle volumes increased in the training group but not the control group (P < 0.05). Relative muscle activity (%MVC) with a helmet decreased after the intervention in the training but not the control group (P = 0.01). Relative muscle activity while wearing a helmet and night vision goggles was higher after intervention in the control group than in the training group (P < 0.01). The perceived muscular strain of the neck muscles induced by the long-arm centrifuge did not differ between the groups. Conclusion Twelve weeks of functional strength training improves the maximal isometric strength and volume of neck and shoulder muscles and leads to lower relative muscle activation upon exposure to elevated Gz forces in a long-arm centrifuge.

The effect of helmet mass and aircraft acceleration on cervical spine loads during typical fast jet aircraft pilot head motions

“…Neck strengthening has been considered J o u r n a l P r e -p r o o f important in preventing neck pain in aircrew. 29,30 This study now provides parameters for exercise prescription which have not previously been available. The next important step is to understand the relationship between operationally significant neck pain complaints and neck workloads.…”

Physical exercise improved muscle strength and pain on neck and shoulder in military pilots

“…Next, the full texts of 22 selected studies were reviewed. Seven studies were eliminated at this stage, and 15 studies were eligible for quantitative synthesis (Hämäläinen et al, 1993;Newman, 1997;Albano and Stanford, 1998;Jones et al, 2000;Alricsson et al, 2004;Burnett et al, 2005;De Loose et al, 2008;Ang et al, 2009;Lange et al, 2013;Salmon et al, 2013;Lange et al, 2014;Murray et al, 2017;Bahat et al, 2020;Murray et al, 2020;Rausch et al, 2021). The PRISMA flow chart for study selection is presented in Figure 1.…”

“…This increase rate is undoubtedly related to the improvement of aircraft performance. In addition, pain relief through special head positions in a confined cabin is not satisfactory (Rausch et al, 2021). The method of changing the design of seat backrest or cabin environment is not only time-consuming but also requires considerable economic investment.…”

“…In many RCTs, strong evidence supports the effectiveness of physical exercise for neck pain (Sjøgaard et al, 2014;Saeterbakken et al, 2017;Park and Lee, 2020). The main purpose of exercise for pilots is to improve the ability to resist high Gz acceleration by improving the strength of the neck muscles and strengthening the control of the muscles (Rausch et al, 2021). In this study, we investigated the effects of physical exercise in military pilots on neck and shoulder muscle strength and pain base on a meta-analysis of previous studies, to provide more scientific and appropriate guidance for future training protocols.…”

Risks and Countermeasures for the Musculoskeletal systems in the Extreme Environment of Aviators and Astronauts

“…This regimen was studied in HPJA personnel to determine whether neck muscles could be built with minimal equipment for aviator needs. At the end of the study, a significant increase in muscle volume and strength was noted [33]. In another randomized control trial, normal exercise training regimens for military pilots were compared to a regimen that contained the same normal training plus training that emphasized neck muscle.…”