Effect of Special Operations Training on Testosterone, Lean Body Mass, and Strength and the Potential for Therapeutic Testosterone Replacement: A Review of the Literature.

OBJECTIVE: Due to physical demands, Special Operations Forces (SOF) endure changes in body composition, work capacity, and endocrine function. These changes result in energy deficits and sleep deprivation, where sleep averaged 3 hours/ day, independently known to decrease testosterone levels. The use of exogenous testosterone shows increases in lean body mass (LBM) and muscle function in healthy males and reverses cachexia in diseased populations. Therefore, the review's primary purpose is to summarize and contrast literature in both SOF and nonmilitary personnel regarding the correlation between negative energy balance, sleep deprivation, and decreased testosterone. The secondary purpose summarizes the effects of exogenous testosterone therapy in healthy males as well as reversing the effects of muscle wasting diseases. METHODS: An online literary search from 1975 to 2015 identified 46 of 71 sources addressing both purposes, and data were summarized into tables providing mean observations. CONCLUSIONS: SOF training results in decreased testosterone (-6.3%), LBM (-4.6%), and strength (-11.7%), tied to energy deficits (-3,351 kcal/day) and sleep deprivation (3 hours/ day). Exogenous testosterone therapy increases LBM (6.2%), strength (7.9-14.8%), reverses cachexia (2.0%) and increases strength (12.7%) in those with chronic diseases. Therefore, testosterone supplementation in SOF may attenuate changes in body composition and muscle function during training and sustained Special Operations (SUSOPS).

Effects of a New Cooling Technology on Physical Performance in US Air Force Military Personnel.

INTRODUCTION: Heat-related illness is a critical factor for military personnel operating in hyperthermic environments. Heat illness can alter cognitive and physical performance during sustained operations missions. Therefore, the primary purpose of this investigation was to determine the effects of a novel cooling shirt on core body temperature in highly trained US Air Force personnel. METHODS: Twelve trained (at least 80th percentile for aerobic fitness according to the American College of Sports Medicine, at least 90% on the US Air Force fitness test), male Air Force participants (mean values: age, 25 ± 2.8 years; height, 178 ± 7.9cm; body weight 78 ± 9.6kg; maximal oxygen uptake, 57 ± 1.9mL/kg/ min; and body fat, 10% ± 0.03%) completed this study. Subjects performed a 70-minute weighted treadmill walking test and 10-minute, 22.7kg sandbag shuttle test under two conditions: (1) "loaded" (shirt with cooling inserts) and (2) "unloaded" (shirt with no cooling inserts). RESULTS: Core body temperature, exercise heart rate, capillary blood lactate, and ratings of perceived exertion were recorded. Core body temperature was lower (ρ = .001) during the 70-minute treadmill walking test in the loaded condition. Peak core temperature during the 70-minute walking test was also significantly lower (ρ = .038) in the loaded condition. CONCLUSION: This lightweight (471g), passive cooling technology offers multiple hours of sustained cooling and reduced core and peak body temperature during a 70-minute, 22.7kg weighted-vest walking test.

Continuous One-Arm Kettlebell Swing Training on Physiological Parameters in US Air Force Personnel: A Pilot Study.

BACKGROUND: The primary aim of this study was to investigate the effects of continuous one-arm kettlebell (KB) swing training on various US Air Force physical fitness testing components. Thirty trained male (n = 15) and female (n = 15) US Air Force (USAF) personnel volunteered and were sequentially assigned to one of three groups based on 1.5-mile run time: (1) KB one-arm swing training, (2) KB one-arm swing training plus highintensity running (KB + run), and (3) traditional USAF physical training (PT) according to Air Force Instruction 36-2905. METHODS: The following measurements were made before and after 10 weeks of training: 1.5-mile run, 1-minute maximal push-ups, 1-minute maximal situps, maximal grip strength, pro agility, vertical jump, 40-yard dash, bodyweight, and percent body fat. Subjects attended three supervised exercise sessions per week for 10 weeks. During each exercise session, all groups performed a 10-minute dynamic warm-up followed by either (1) 10 minutes of continuous KB swings, (2) 10 minutes of continuous kettlebell swings plus 10 minutes of high-intensity running, or (3) 20 minutes of moderate intensity running plus push-ups and sit-ups. Average and peak heart rate were recorded for each subject after all sessions. Paired t tests were conducted to detect changes from pretesting to posttesting within each group and analysis of variance was used to compare between-group variability (ρ ≤ .05). RESULTS: Twenty subjects completed the study. There were no statistically significant changes in 1.5-mile run time between or within groups. The 40- yard dash significantly improved within the KB swing (ρ ≤ .05) and KB + run group (ρ ≤ .05); however, there were no significant differences in the traditional PT group (ρ ≤ .05) or between groups. Maximal push-ups significantly improved in the KB + run group (ρ ≤ .05) and trends toward significant improvements in maximal push-ups were found in both the KB (ρ = .057) and traditional PT (ρ = .067) groups. CONCLUSIONS: This study suggests that continuous KB swing training may be used by airmen as a high-intensity, low-impact alternative to traditional USAF PT to maintain aerobic fitness and improve speed and maximal push-ups.

The Effects of Backwards Running Training on Forward Running Economy in Trained Males.

Backwards running (BR) results in greater cardiopulmonary response and muscle activity compared with forward running (FR). BR has traditionally been used in rehabilitation for disorders such as stroke and lower leg extremity injuries, as well as in short bursts during various athletic events. The aim of this study was to measure the effects of sustained backwards running training on forward running economy in trained male athletes. Eight highly trained, male runners (26.13 ± 6.11 years, 174.7 ± 6.4 cm, 68.4 ± 9.24 kg, 8.61 ± 3.21% body fat, 71.40 ± 7.31 ml·kg(-1)·min(-1)) trained with BR while harnessed on a treadmill at 161 m·min(-1) for 5 weeks following a 5-week BR run-in period at a lower speed (134 m·min(-1)). Subjects were tested at baseline, postfamiliarized, and post-BR training for body composition, a ramped VO2max test, and an economy test designed for trained male runners. Subjects improved forward running economy by 2.54% (1.19 ± 1.26 ml·kg(-1)·min(-1), p = 0.032) at 215 m·min(-1). VO2max, body mass, lean mass, fat mass, and % body fat did not change (p > 0.05). Five weeks of BR training improved FR economy in healthy, trained male runners without altering VO2max or body composition. The improvements observed in this study could be a beneficial form of training to an already economical population to improve running economy.

The use of dexamethasone in support of high-altitude ground operations and physical performance: review of the literature.

OBJECTIVE: Military Special Operators (SOs) are exposed environmental conditions that can alter judgment and physical performance: uneven terrain, dryness of ambient air, reduction of air density, and a diminished partial pressure of oxygen. The primary purpose of this review was to determine the medical efficacy of dexamethasone as an intervention for the prevention and treatment of high-altitude illness. The secondary purpose was to determine its ability to maintain physical performance of SOs at high altitudes. METHODS: A search of the literature from 1970 to 2014 was performed, locating 61 relevant articles, with 43 addressing the primary and secondary purposes of this literature review. CONCLUSIONS: The review indicates that dexamethasone is an effective prevention and treatment intervention for high-altitude illness. Commonly used dosages of either 2 mg every 6 hours or 4 mg every 12 hours can prevent high-altitude illnesses in adults. Currently in USSOCOM operations, there is an option to use 4 mg every 6 hours (concurrently with acetazolamide 125 mg bid) if ascending rapidly to or above 11,500 ft without time for acclimatization. Researchers also determined that acute exposure to high altitude, even in asymptomatic subjects, resulted in small cognitive deficits that could be reversed with dexamethasone. Dexamethasone may also help improve cognition and maximal aerobic capacity in SOs who are susceptible to high-altitude pulmonary edema.