The present study demonstrated that military training needs a greater variation in training stimulus to induce more effective training adaptations, especially, when considering the development of maximal or explosive strength and maximal aerobic capacity. Training programs should be well periodised so that total training load increases progressively but also includes sufficient recovery periods. In addition, some individualized programming is required to avoid unnecessary injuries and overloading because the differences in initial physical fitness of soldiers can be very high.

In this study, we observed a decrease in leg strength from the PRE to MID measurements. When the physical load requirements during the MFT decreased after the MID measurements, leg strength increased. In addition, the shooting score from the standing position decreased from the PRE to MID measurements and improved significantly from the MID to POST measurements. The prone shooting score did not show any significant changes during the study period. Significant positive correlations were found between the changes in standing shooting score and the changes in strength for the legs and upper body. There was a positive correlation between the changes in serum COR concentrations and changes in standing shooting score. Altogether, the present study showed that the prolonged MFT has adverse effect on the strength levels and the shooting ability in warfighters. This shows that ensuring warfighters get an appropriate amount of rest while performing their duties is important. Shooting from a prone position was not affected by the changing workloads and this result indicated that soldiers should shoot from a prone position, whenever possible, especially when fatigued.

Physical fitness is crucial to warfighters’ performance in the battlefield. Previous studies have shown negative changes in their hormonal and neuromuscular responses induced by military field training (MFT). The purpose of this study was to investigate the changes in hormonal and immunological values and body composition during a prolonged MFT and to find out how warfighters’ physical condition influences these changes. Conscripts (n = 49, age 20 ± 1 years, height 179 ± 9 cm, body mass 73.8 ± 7.8 kg, fat 12.6 ± 3.7% and BMI 23 kg/m²) were measured before, during, after MFT, and after a 4‐day recovery period. Serum insulin‐like growth factor‐1 (IGF‐1), tumor necrosis factor alpha (TNF‐α), interleukin‐6 (IL‐6) concentrations, creatine kinase (CK) activity and leptin concentration were analyzed as well as body composition throughout MFT. Neuromuscular performance was assessed via lower and upper body muscle endurance at the beginning of the study. During MFT, there was a significant decrease (P < 0.05) in body mass (2.3%), fat mass (7.7%) and in muscle mass (2.2%), but all of these values recovered to PRE‐levels after the recovery period. Serum IGF‐1 (22%) and leptin decreased (66%) while CK increased (88%) significantly (P < 0.05) during MFT but recovered at the end of MFT. Upper body dynamic and trunk isometric muscular endurance had a positive correlation (r = 0.37. P < 0.05) with the change in IGF‐1 during MFT and a negative correlation with the changes in CK (−0.34, P < 0.05). The results show that there were negative changes in conscript's body composition and hormonal and immunological values during the prolonged MFT. These changes suggest that the physiological stress was high during MFT. High levels of upper body and trunk muscular strength were negatively correlated with warfighters’ physiological effects and should therefore be developed prior to actual deployment to reduce the physical decline experienced during prolonged MFTs.

This study demonstrated slight decrements in warfighter physical performance during the 21-d MFT. The conscripts were overloaded during MFT, but 4 d of recovery seemed not to be enough to obtain the PRE measurement values in physical performance. This study also showed changes in the muscular endurance levels and PA during the 21-d MFT. It is important for warfighters to have a good physical fitness level PRE training or combat. As the prolonged MFT may have adverse effects in warfighters muscular endurance and PA levels, it is important to have sufficient recovery time after long MFT to regain combat readiness.

Introduction/Purpose: Physical activity and sedentary time may associate with physical fitness and body composition. Yet, there exists some observational studies that have investigated the associations of device-based measures of sedentary time and physical activity (PA) with cardiorespiratory fitness (CRF) and body composition but associations with muscular fitness (MF) are less studied.Methods: Objective sedentary time and physical activity was measured by a hip worn accelerometer from 415 young adult men (age: mean 26, standard deviation 7 years). Cardiorespiratory fitness (VO2max) (CRF) was determined using a graded cycle ergometer test until exhaustion. Maximal force of lower extremities was measured isometrically and lower body power was assessed using standing long jump (MF). Body composition was determined with bioimpedance method. Single and compositional approach was used in regression analysis.Results: Mean sedentary time was 707 (standard deviation 133) minutes per day (77 ± 8% of the wear time). Volumes of all PA intensities were positively associated with CRF and associations showed linearly increasing magnitudes with higher intensities in single regression models adjusted for age and smoking (p &lt; 0.001). Similarly, PA intensities were positively associated with lower body MF, however, with weaker associations (p &lt; 0.005). After further adjustment for resistance training, the associations remained significant. The associations of the relative distribution of time within sedentary behavior (SB), light intensity PA (LPA) and moderate-to-vigorous PA (MVPA) behaviors as a whole with using compositional analysis further revealed that within the composition MVPA and SB were positively associated with CRF and MF (p &lt; 0.001), while LPA was not. In addition, within the composition, accumulated PA bouts lasting more than 3 min were consistently associated with CRF and MF, and with all body composition variables (p &lt; 0.001), while sedentary time was associated with body fat percentage (p &lt; 0.001).Conclusion: Promoting physical activity and reducing sedentary time may have positive influence on physical fitness and body fat content, and thereby may offer positive health effects. Physical activity of higher intensities may offer greater benefits.