Author(s): MATIAS, C.N.1, BORGES, H.1, VALAMATOS, M.J.V.2,3, CAVACA, M.L.2,3, JOÃO, F.2, CARDOSO, J.5, REIS, J.F.2,3, MORGADO, J.P.1, VAZ, J.6, BAPTISTA, F.2, MONTEIRO, C.P.2, FERNANDES, T.M.4, CURTO, D.2, NICOLAU, M.2, JESUS, F.2, CARLOS, R.7, ESPADA, M.8, PARDAL, M.9, VITORINO, S.9, NUNES, T.9, RIBEIRO, H.9, SILVA, C.9, ROSÁRIO, I.9, LOPES, M.9, Institution: COFAC - UNIVERSIDADE LUSOFONA, Country: PORTUGAL, Abstract-ID: 1818

INTRODUCTION:
Most armed forces are involved in national and international deployments where fine motor skills, mental acuity, and physical performance are simultaneously required. Portuguese Air Force crews deployed on search and rescue missions are multidisciplinary teams of 5 elements comprising these different tasks.
Body composition and strength are significant factors in the military, as effective performance in their duties is crucial for mission success. However, research on the effects of military deployments is limited. In terms of physical fitness, there is some consistency in the findings: a decrease in aerobic capacity and an increase/maintenance of muscular strength, power, and endurance. In terms of body composition, the only consistent result is a reduction in weight.
Bioelectrical impedance analysis (BIA) allows a non-invasive, economical, and practical field evaluation of body composition and phase angle (PhA). Moreover, PhA has been suggested as an indicator of cellular integrity and muscle quality and a predictor of physical performance, as it represents the synergistic effect of physical activity, recovery (e.g.sleep) and nutrition.
This study evaluates the effects of a 15-day deployment for search and rescue missions on the body composition, PhA and strength of the airmen of the Portuguese Air Force flight squads.
METHODS:
Healthy military males (N=23, 9 pilots, 5 co-pilots, 2 systems operators and 7 rescue workers) were evaluated the day before and immediately after deployment. Body composition (fat and fat-free mass (FM and FFM), total-body, intra and extracellular water (TBW, ECW, ICW) and PhA were assessed through BIA (BIA-101, Akern). Maximal strength and rate of force development (RFD) were evaluated through 3 maximal voluntary isometric contractions in different conditions: (i) hand grip, using a portable dynamometer (Jamar); (ii) dominant knee extensors and flexors test, using a HUMAC isokinetic dynamometer (HUMAC NORM, CSMI Medical Solutions); and (iii) isometric mid-thigh pull (IMPT), performed on a homemade force plate.
Paired sample t-test was performed, and significance was set at p<0.05.
RESULTS:
Participants presented differences in body composition and strength variables after deployment. ECW increased from 19.1 ± 2.2 to 19.9 ± 2.3 kg (p=0.008), while a decrease in PhA (from 7.1 ± 0.8 to 6.9 ± 0.6º, p=0.038), FM (from 14.8 ± 4.6 to 13.6 ± 4.1 kg, p=0.024), flexors peak torque (from 143.0 ± 25.9 to 134.0 ± 23.2 Nm, p=0.043), and IMTP RFD (from 11.6 ± 2.4 to 9.9 ± 2.3 N/ms, p=0.004) was observed.
CONCLUSION:
Our findings indicate that, after a 15-day deployment, members of the flight squads in the Portuguese Air Force experienced a decrease in PhA and in the ability to generate lower limb maximal and explosive force, even though a slight (non-significant) increase in FFM was observed. Therefore, the observed decline in phase angle and strength may be attributed to factors such as nutritional status, recovery time (including sleep), and overall fatigue.