Critical Velocity Is Associated With Combat-Specific Performance Measures in a Special Forces Unit.

The purpose of this study was to examine the relationship between critical velocity (CV) and anaerobic distance capacity (ADC) to combat-specific tasks (CST) in a special forces (SFs) unit. Eighteen male soldiers (mean ± SD; age: 19.9 ± 0.8 years; height: 177.6 ± 6.6 cm; body mass: 74.1 ± 5.8 kg; body mass index [BMI]: 23.52 ± 1.63) from an SF unit of the Israel Defense Forces volunteered to complete a 3-minute all-out run along with CST (2.5-km run, 50-m casualty carry, and 30-m repeated sprints with "rush" shooting [RPTDS]). Estimates of CV and ADC from the 3-minute all-out run were determined from data downloaded from a global position system device worn by each soldier, with CV calculated as the average velocity of the final 30 seconds of the run and ADC as the velocity-time integral above CV. Critical velocity exhibited significant negative correlations with the 2.5-km run time (r = -0.62, p < 0.01) and RPTDS time (r = -0.71, p < 0.01). In addition, CV was positively correlated with the average velocity during the 2.5-km run (r = 0.64, p < 0.01). Stepwise regression identified CV as the most significant performance measure associated with the 2.5-km run time, whereas BMI and CV measures were significant predictors of RPTDS time (R(2) = 0.67, p ≤ 0.05). Using the 3-minute all-out run as a testing measurement in combat, personnel may offer a more efficient and simpler way in assessing both aerobic and anaerobic capabilities (CV and ADC) within a relatively large sample.

Examination of the Effectiveness of Predictors for Musculoskeletal Injuries in Female Soldiers.

The amount of training days lost to injury during military training has highlighted the need to identify a screening tool to predict injury. One hundred and fifty-eight female soldiers from the Combat Fitness Instructor Course (CFIC) of the Israel Defense Forces volunteered to participate in this study. All soldiers were free of orthopedic and neurologic conditions for at least one month before the study. All participants performed a battery of measurements during the first week of the course. Measures included anthropometric, functional movement screen (FMS), power performances (counter movement jump [CMJ], drop jump, single leg triple hop jump [SLTH], 10-m sprint) and a 2K run. Injury data was collected throughout the 3 month course. Median tests were used to compare between injured/non-injured soldiers. Chi-square and/or logistic regression analysis was used to examine the association between various predictors and injury. Percent body fat [%BF] was higher (p = 0.04), distance for SLTH was less for both left and right legs (p = 0.029, p = 0.047 respectively) and 2K run was slower (p =0.044) in injured compared to non-injured soldiers. No differences between groups were noted in total FMS score, however more zero scores in one or more movement pattern were found in the injured group (51.35 % vs. 30.5% p=0.0293). Only %BF, 2K run and SLTH distance were significant predictors of injury (p = 0.05, p = 0.02, p =0.016 respectively). The results of this study indicated that the FMS total score is not a predictor of injury in female soldiers in a CFIC. We found that %BF, SLTH, 2K run time, 10 meter sprint time and zero scores differentiated between injured and non-injured soldiers. In addition, %BF, 2K run and SLTH were each found to be separate predictors of injury. Further research is needed to determine threshold scores that predict injury. Key pointsA total of 145 injuries were reported during the three month Combat Fitness Instructor Course in a female soldiers, 37 of these injuries resulted in absence from at least two days of training.FMS total score is not a predictor of injury in female soldiers in a CFIC. However, a score of zero, which is indicative of pain during movement, could serve as a warning sign for potential injury.%BF, SLTH, 10 meter sprint, 2K run and number of zero scores in FMS appear to differentiate between injured and non-injured soldiersSLTH, 2K run and body fat % are each separate predictors of injury for female soldiers in the CFIC.

Effect of cardiovascular and muscular endurance is not associated with stress fracture incidence in female military recruits: a 12-month follow up study.

BACKGROUND: Stress fracture (SF) is a common injury among military recruits, especially among women, during the army basic training (ABT). The purpose of this study was to evaluate the effects of health habits and physical activity before recruitment on the fitness level and the incidence of SF during the 4-month ABT. METHODS: We screened 226 female recruit volunteers (weight: 60.5±10 kg; height: 163±6 cm) from an integrated combat unit and 124 aged-matched female controls (weight: 57.0±8.3 kg, height 162±7 cm) from a non-combat unit. A self-report questionnaire on their habits pertaining to smoking, physical activity, and orthopedic injuries prior to recruitment were analyzed in relation to the incidences of SF during ABT. RESULTS: Aerobic fitness was similar between the two groups. The overall incidence of SFs was 10.2%. Physical training prior to recruitment had no significant effect on the incidence of SF during ABT (11.7% vs. 9.6% in those who trained and did not train before recruitment, respectively) (Odds ratio, OR)=1.24, p=0.236). Nearly 42% of the female recruits smoked regularly, and the incidence of SFs among smokers was 10.5% compared with 9.9% among the non-smokers (OR=1.07, p=0.188). The overall incidence of SFs 12 months after recruitment was 1.78%. The use of contraceptive medication did not affect the incidence of SF: 10.0% among prior-trained vs. 6.4% in non-prior trained (p>0.05) recruits. SFs were not correlated to these variables at the end of the ABT program and 16 months after recruitment. CONCLUSIONS: In the present female cohort, physical activity prior to recruitment had no protective effect against SF during or after ABT. The incidence of SFs during the 12-month period after ABT was negligible.

ß-alanine supplementation improves tactical performance but not cognitive function in combat soldiers.

BACKGROUND: There are no known studies that have examined ß-alanine supplementation in military personnel. Considering the physiological and potential neurological effects that have been reported during sustained military operations, it appears that ß-alanine supplementation may have a potential benefit in maintaining physical and cognitive performance during high-intensity military activity under stressful conditions. The purpose of this study was to examine the effect of 28 days of ß-alanine ingestion in military personnel while fatigued on physical and cognitive performance. METHODS: Twenty soldiers (20.1 ± 0.9 years) from an elite combat unit were randomly assigned to either a ß-alanine (BA) or placebo (PL) group. Soldiers were involved in advanced military training, including combat skill development, navigational training, self-defense/hand-to-hand combat and conditioning. All participants performed a 4-km run, 5-countermovement jumps using a linear position transducer, 120-m sprint, a 10-shot shooting protocol with assault rifle, including overcoming a misfire, and a 2-min serial subtraction test to assess cognitive function before (Pre) and after (Post) 28 days of supplementation. RESULTS: The training routine resulted in significant increases in 4-km run time for both groups, but no between group differences were seen (p = 0.597). Peak jump power at Post was greater for BA than PL (p = 0.034), while mean jump power for BA at Post was 10.2% greater (p = 0.139) than PL. BA had a significantly greater (p = 0.012) number of shots on target at Post (8.2 ± 1.0) than PL (6.5 ± 2.1), and their target engagement speed at Post was also significantly faster (p = 0.039). No difference in serial subtraction performance was seen between the groups (p = 0.844). CONCLUSION: Results of this study indicate that 4-weeks of ß-alanine ingestion in young, healthy soldiers did not impact cognitive performance, but did enhance power performance, marksmanship and target engagement speed from pre-ingestion levels.

Differences in physical fitness of male and female recruits in gender-integrated army basic training.

PURPOSE: To evaluate gender differences in physical fitness before and after a 4-month gender-integrated basic training (BT) course and to determine whether this program effectively narrowed the differences between male and female soldiers in physical fitness parameters. METHODS: One hundred and thirty-seven soldiers (109 females and 28 males) successfully completed a 4-month BT course in the Israeli Defense Forces (IDF). The subject's physical fitness was evaluated pre- and post-BT by three laboratory tests [the maximal aerobic capacity (VO2max), the Leonardo Ground Reaction Force Plate, and the Wingate Anaerobic Test (WAnT)] and by the IDF physical fitness test (IDF-PT). RESULTS: Females significantly improved their scores in the IDF-PT and laboratory aerobic tests, whereas males significantly improved only in the IDF-PT. After BT, gender differences narrowed by approximately 4% in all tests except upper body strength. Although fitness improvement after BT was marginally higher in females than males, resulting in a slight narrowing of the gender differences, a significant gender gap in physical fitness still exists after BT. CONCLUSIONS: There was only a small overlap in physical abilities at the beginning of BT, which indicated vast differences in physical fitness between the genders. As expected, integrated combat BT improved physical fitness. Although females demonstrated marginally higher improvement in aerobic capacity, basic physiological gender differences were still evident at the end of the training regimen.