Effect of Physical Training on Body Composition in Brazilian Military

Influence of the Type of Physical Training on the Physical Fitness of Army Cadets

INTRODUCTION

Military Physical Training programs represent a constant challenge for the Armed Forces to improve body composition indices and physical fitness levels. This study aimed to verify the influence of the type of training on the physical fitness and body composition of army cadets, using 2 strategies: a sports program (Athletes group) and conventional physical training (Traditional group).

MATERIALS AND METHODS

This study involved new entrant male cadets who were selected for the Athletes group (n = 243, 19.08 ± 1.23 years) or the Traditional group (n = 356, 18.89 ± 0.97 years), with assessments occurring before and after the period of training (31.4 ± 3.9 weeks). Dual-energy X-ray absorptiometry was used to measure the bone mineral content (BMC), fat mass (FM), percentage of fat mass (%FM), and lean soft tissue (LST). The physical tests evaluated the 3,000 m run (RUN), 50 m swim (SWIM), pull-ups (PULL) on the horizontal bar, push-ups (PUSH) on the ground, and abdominal flexion (SITUP).

RESULTS

Time × group interaction effects were observed for BMC (P < .001), LST (P < .023), RUN (P < .001), PULL (P = .006), PUSH (P < .001), SITUP (P = .007), and SWIM (P < .001). A significant effect of time was noted for all variables analyzed in both groups, except %FM. The Athletes group achieved better results in body composition and in PULL, PUSH, RUN, and SWIM at baseline and after the training period. The Traditional group demonstrated higher relative changes (%) after the training period in the LST (P = .001), PULL (P < .001), PUSH (P < .001), SITUP (P < .004), and SWIM (P < .001) compared to the Athletes group.

CONCLUSION

Both physical training programs improved body composition and physical performance.

Phase angle, muscle tissue, and resistance training

The biophysical response of the human body to electric current is widely appreciated as a barometer of fluid distribution and cell function. From distinct raw bioelectrical impedance (BIA) variables assessed in the field of body composition, phase angle (PhA) has been repeatedly indicated as a functional marker of the cell's health and mass. Although resistance training (RT) programs have demonstrated to be effective to improve PhA, with varying degrees of change depending on other raw BIA variables, there is still limited research explaining the biological mechanisms behind these changes. Here, we aim to provide the rationale for the responsiveness of PhA determinants to RT, as well as to summarize all available evidence addressing the effect of varied RT programs on PhA of different age groups. Available data led us to conclude that RT modulates the cell volume by increasing the levels of intracellular glycogen and water, thus triggering structural and functional changes in different cell organelles. These alterations lead, respectively, to shifts in the resistive path of the electric current (resistance, R) and capacitive properties of the human body (reactance, Xc), which ultimately impact PhA, considering that it is the angular transformation of the ratio between Xc and R. Evidence drawn from experimental research suggests that RT is highly effective for enhancing PhA, especially when adopting high-intensity, volume, and duration RT programs combining other types of exercise. Still, additional research exploring the effects of RT on whole-body and regional BIA variables of alternative population groups is recommended for further knowledge development.

Editorial: New Training Strategies and Evaluation Methods for Improving Health and Physical Performance

Physical activity is among the most effective methods for improving health, body composition, and physical function, and its practice is suitable for every population [...].