Risk Factors for Sprains and Strains Among Physically Active Young Men: A US Army Study.

This investigation aimed to identify risk factors for lower extremity sprain/strain injuries in physically active men. Lower extremity (LE) sprain/strain injuries are a significant source of morbidity among physically active populations. Data on and risk factors for injuries, including personal characteristics, and physical training and fitness were obtained from male Soldiers in an operational US Army division (N=6,865) by survey. Injury risks, risk ratios (RR), odds ratios (OR), and 95% confidence intervals (95% CI) were calculated. Multivariate analysis utilized logistic regression. Self-reported injury incidence for the prior 12 months was 43% (n=2,939), with 30% (n=878) of injuries attributed to LE sprains/strains. Lower extremity sprain/strain injuries were most commonly caused by falls, jumps, trips, or slips (49.4%), occurred while running (30.6%), and often resulted in limited duty profiles (64%). Higher risk of LE sprain/strain injury was independently associated with higher body mass index (ORoverweight/normal=1.2, 95% CI: 1.0-1.5), (ORobese/normal=1.4, 95% CI: 1.1-1.9), lower aerobic endurance (from 2-mile run time) (ORQuartile 2 (Q2)/Quartile 4 (Q4)=1.4, 95% CI: 1.0-1.8), (ORQuartile 1 (Q1)/Q4=1.6, 95% CI: 1.3-2.1), and lower core strength (sit-up repetitions) (ORQ1/Q4=1.4, 95% CI: 1.1-1.8). Lower risk of LE sprain/strain injury was associated with performing unit resistance training 3 or more times per week (OR3 times/none=0.5, 95% CI: 0.3-0.8). LE sprain/strain injuries contribute a significant portion of injuries among US Army Soldiers. Emphasis on aerobic fitness, core strength, and resistance training may help reduce the risk of LE sprain/strain injury among physically active men.

Functional Movement Screen: Pain versus composite score and injury risk.

OBJECTIVES: The Functional Movement Screen (FMS™) has been used as a screening tool to determine musculoskeletal injury risk using composite scores based on movement quality and/or pain. However, no direct comparisons between movement quality and pain have been quantified. DESIGN: Retrospective injury data analysis. METHODS: Male Soldiers (n=2154, 25.0±1.3years; 26.2±.7kg/m2) completed the FMS (scored from 0 points (pain) to 3 points (no pain and perfect movement quality)) with injury data over the following six months. The FMS is seven movements. Injury data were collected six months after FMS completion. Sensitivity, specificity, receiver operator characteristics and positive and negative predictive values were calculated for pain occurrence and low (≤14 points) composite score. Risk, risk ratios (RR) and 95% confidence intervals were calculated for injury risk. RESULTS: Pain was associated with slightly higher injury risk (RR=1.62) than a composite score of ≤14 points (RR=1.58). When comparing injury risk between those who scored a 1, 2 or 3 on each individual movement, no differences were found (except deep squat). However, Soldiers who experienced pain on any movement had a greater injury risk than those who scored 3 points for that movement (p<0.05). A progressive increase in the relative risk occurred as the number of movements in which pain occurrence increased, so did injury risk (p<0.01). CONCLUSIONS: Pain occurrence may be a stronger indicator of injury risk than a low composite score and provides a simpler method of evaluating injury risk compared to the full FMS.

Evaluating Injury Risk and Gender Performance on Health- and Skill-Related Fitness Assessments.

Grier, TL, Canham-Chervak, M, Bushman, TT, Anderson, MK, North, WJ, and Jones, BH. Evaluating injury risk and gender performance on health- and skill-related fitness assessments. J Strength Cond Res 31(4): 971-980, 2017-The purpose of this analysis was to investigate the association of injury risk and gender performance on health- and skill-related fitness assessments. A survey was used to collect personal characteristics and Army Physical Fitness Test scores (2-mile run, push-ups, and sit-ups). Within the same day, 9 physical fitness assessments were performed. Percent body fat was estimated using height, weight, age, and sex. All fitness assessment data were categorized into tertiles of high, moderate and low performance. To investigate potential injury risk predicted by fitness assessment performance, injury risk ratios, odds ratios (ORs), and 95% confidence intervals (CIs) were calculated using medical record data. A total of 3,264 soldiers completed surveys and physical fitness assessments. Tertiles of fitness performance with men and women combined showed that on an average, 14% of women and 70% of men were in the moderate- and high-performance groups. Among men, higher injury risk was independently associated with low performance on a 2-mile run (ORslow/fast = 1.51, 95% CI 1.18-1.94) and low performance on a weighted 300-yard shuttle run (ORslow/fast = 1.36, 95% CI 1.06-1.74). For women, a higher risk of injury was associated with low performance on the 2-mile run (ORslow/fast = 2.38, 95% CI 1.04-5.74). Therefore, out of the 13 fitness assessments, the 2-mile run and weighted 300-yard shuttle run can also (in addition to measuring performance) be utilized to identify soldiers or athletes who are at a higher risk of experiencing an injury.

Effects of Physical Training and Fitness on Running Injuries in Physically Active Young Men.

Grier, TL, Canham-Chervak, M, Anderson, MK, Bushman, TT, and Jones, BH. Effects of physical training and fitness on running injuries in physically active young men. J Strength Cond Res 31(1): 207-216, 2017-The purpose of this investigation was to determine the effects of physical training (PT) and fitness on risks for running-related injuries (RRIs) in physically active young men. Personal characteristics, PT, Army Physical Fitness Test scores, and injury data were obtained by survey. Army Physical Fitness Test variables (push-ups, sit-ups, and 2-mile run) were converted into quartiles (Q), where Q1 = lowest performance and Q4 = highest performance. Odds ratios (OR) and 95% confidence intervals (95% CI) were calculated using multivariate logistic regression. Over 4,000 (n = 4,236) soldiers were surveyed. Running injury incidence was 14%. A greater risk of an RRI was associated with older age (OR31+/<22 years = 1.62, 95% CI, 1.21-2.18), higher BMI ((Equation is included in full-text article.)), and total distance ran per week during unit PT (OR16.1+/1-5 miles = 1.66, 95% CI, 1.15-2.41). A lower risk of an RRI was associated with total distance run per week during personal PT (OR5.1-10/1-5 miles = 0.70, 95% CI, 0.53-0.91, OR10.1-16 +/1-5 miles = 0.58, 95% CI, 0.35-0.97, OR16.1+/1-5 miles = 0.54, 95% CI, 0.30-0.98), higher aerobic endurance as measured by 2-mile run performance (ORQ4/Q1 = 0.50, 95% CI, 0.35-0.72), and unit resistance training ≥3 times a week (OR≥3 times per week/none = 0.46, 95% CI, 0.29-0.73). Greater personal PT running mileage decreased injuries in this population suggesting that the increased protective effect of higher aerobic fitness outweighed the injurious effect of running more miles during personal PT. Countermeasures to prevent RRIs could entail enhancing aerobic endurance, providing opportunities for personal aerobic training, monitoring for excessive unit PT running mileage and encouraging unit resistance training ≥3 times per week.

Effect of Mandatory Unit and Individual Physical Training on Fitness in Military Men and Women.

PURPOSE: The purpose of this study was to look at the effect of additional individual physical training (PT) in addition to mandatory unit PT as well as other risk factors on physical fitness. DESIGN: A cross-sectional design. SETTING: This study was conducted on a US military installation. PARTICIPANTS: Participants were 6290 male and 558 female active duty US Army soldiers in 3 light infantry brigades. MEASURES: Participants completed self-administered questionnaires asking about individual characteristics, PT, and physical fitness. Cut points were established for soldiers scoring within the top 33% for each of the 3 Army Physical Fitness Test events (2-mile run, sit-ups, and push-ups) and top 50% in each of the tests combined for overall performance. ANALYSIS: Odds ratios and 95% confidence intervals from multivariate analyses were calculated. RESULTS: Variables impacting physical fitness performance of men and women included increased body mass index, leading unit PT sessions, and individual distance running mileage. Other variables impacting physical performance for men included increased age, smoking, and individual resistance training. CONCLUSION: Soldiers performing additional individual PT demonstrated a positive influence on fitness compared to unit PT participation alone. Increased age and being overweight/obese negatively influenced physical fitness. To enhance fitness performance through unit PT, running by ability groups and resistance training should be encouraged by leadership.

The Functional Movement Screen and Injury Risk: Association and Predictive Value in Active Men.

BACKGROUND: The Functional Movement Screen (FMS) is a series of 7 tests used to assess the injury risk in active populations. PURPOSE: To determine the association of the FMS with the injury risk, assess predictive values, and identify optimal cut points using 3 injury types. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: Physically active male soldiers aged 18 to 57 years (N = 2476) completed the FMS. Demographic and fitness data were collected by survey. Medical record data for overuse injuries, traumatic injuries, and any injury 6 months after the FMS assessment were obtained. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated along with the receiver operating characteristic (ROC) to determine the area under the curve (AUC) and identify optimal cut points for the risk assessment. Risks, risk ratios (RRs), odds ratios (ORs), and 95% CIs were calculated to assess injury risks. RESULTS: Soldiers who scored ≤14 were at a greater risk for injuries compared with those who scored >14 using the composite score for overuse injuries (RR, 1.84; 95% CI, 1.63-2.09), traumatic injuries (RR, 1.26; 95% CI, 1.03-1.54), and any injury (RR, 1.60; 95% CI, 1.45-1.77). When controlling for other known injury risk factors, multivariate logistic regression analysis identified poor FMS performance (OR [score ≤14/19-21], 2.00; 95% CI, 1.42-2.81) as an independent risk factor for injuries. A cut point of ≤14 registered low measures of predictive value for all 3 injury types (sensitivity, 28%-37%; PPV, 19%-52%; AUC, 54%-61%). Shifting the injury risk cut point of ≤14 to the optimal cut points indicated by the ROC did not appreciably improve sensitivity or the PPV. CONCLUSION: Although poor FMS performance was associated with a higher risk of injuries, it displayed low sensitivity, PPV, and AUC. On the basis of these findings, the use of the FMS to screen for the injury risk is not recommended in this population because of the low predictive value and misclassification of the injury risk.

Validity of Self-Reported Physical Fitness and Body Mass Index in a Military Population.

Many epidemiological studies rely on valid physical fitness data. The purpose of this investigation was to assess the validity of self-reported Army Physical Fitness Test (APFT) data and determine whether men and women recall APFT performance differently. U.S. Army soldiers (N = 1,047) completed a survey, including questions on height, weight, and most recent APFT performance. Height, weight, and APFT performance were also obtained from unit records. The mean ± SDs for unit and self-reported push-up repetitions were 63.5 ± 13.1 and 66.3 ± 14.0 for men and 37.7 ± 12.8 and 40.2 ± 12.8 for women, respectively. The mean ± SD for unit- and self-reported sit-up repetitions were 66.3 ± 11.4 and 68.1 ± 12.1 for men and 64.2 ± 13.6 and 66.5 ± 12.9 for women, respectively. The mean ± SD unit- and self-reported 2-mile run times were 15.2 ± 1.8 and 14.9 ± 1.6 minutes for men, and 18.0 ± 2.9 and 17.4 ± 1.9 minutes for women, respectively. Unit- and self-reported body mass indices (BMIs) (calculated by height and weight) were 26.4 ± 3.4 and 26.3 ± 3.6 for men and 24.6 ± 2.8 and 24.2 ± 3.3 for women. Correlations between unit- and self-reported scores for push-ups, sit-ups, 2-mile run, height, weight, and BMI were 0.82, 0.78, 0.85, 0.87, 0.97, and 0.88 for men and 0.86, 0.84, 0.87, 0.78, 0.98, and 0.78 for women, respectively. On average, men and women slightly overreported performance on the APFT and overestimated height, resulting in underestimated BMI. There was no difference in recall ability between men and women (p > 0.05). The very good to excellent correlations (r = 0.78-0.98) between unit- and self-reported scores indicate that self-reported data are valid for capturing physical fitness performance in this population.

Pain on Functional Movement Screen Tests and Injury Risk.

The Functional Movement Screen (FMS) is a tool intended to evaluate limitations or asymmetries of movement to detect individuals at risk for exercise- and sports-related injury. The purpose was to determine the association and predictive value of specific FMS tests with injury risk in physically active men. Soldiers aged 18-57 years completed the FMS (n = 2,476). Demographic and fitness data were collected by survey. Medical record data for any, overuse, and traumatic injury 6 months after the assessment were obtained. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value were calculated along with receiver operator characteristics to determine area under the curve (AUC). Risks, risk ratios, odds ratios (ORs), and 95% confidence intervals were calculated to assess injury risks. Multivariate logistic regression identified that pain on 5 of the 7 tests was associated with greater risk for any injury (OR = 1.50-3.51): deep squat, hurdle step, in-line lunge, trunk stability push-up, and rotary stability. However, FMS registered low sensitivity, PPV, and AUC for all 7 tests for the 3 injury types (2-24% sensitivity, 16-74% PPV, and 50-58% AUC). Although the presence of pain was associated with a higher risk of injury on 5 tests, a low sensitivity, PPV, and AUC were displayed. Therefore, caution is advised when implementing the FMS as a screening tool in an Army or similarly active population as it could lead to prevention and treatment resources being directed toward individuals who are not at greater risk for injury.

Physical training, smoking, and injury during deployment: a comparison of men and women in the US Army.

PURPOSE: To investigate changes in physical training (PT), fitness, and injury during deployment and identify differences between men and women. METHODS: Data were collected on male and female US Army Soldiers through self-reported surveys completed before and after deployment to Afghanistan. Changes in physical training activities, physical fitness, injury incidence, BMI, and smoking status were analyzed. Descriptive statistics were used to compare before deployment and deployment results and differences between men and women. RESULTS: Surveys were completed by 727 men and 43 women. The percentage of Soldiers engaging in unit PT running of 5 miles or more per week decreased by almost half for men and women. The percentage of Soldiers doing personal PT running of 5 miles or more per week and engaged in resistance training 3 or more days per week more than doubled for men and women during deployment. Cardiorespiratory endurance for women improved by 50 seconds (P=.06) and for men declined by 29 seconds (P<.01), while muscular endurance increased by 0.6 repetitions (P<.01) during deployment. Injury rates for men decreased, on average, 36.2 to 19.0 injuries per 1,000 Soldiers per month (P=.01). Injury rates for women decreased on average from 42.6 to 14.0 injuries per 1,000 Soldiers per month (P=.02). During deployment, BMI did not change for men or women and smoking increased 19% for men (P<.01), but did not increase for women. CONCLUSION: Comparisons of physical training activities and health behavior among men and women before and during deployment suggests that increased resistance training could be recommended for women and smoking cessation for men. Given the potentially important role of personal PT in maintaining physical fitness in the deployment environment, future work should support provision of the necessary environment and equipment for Soldiers to perform personal PT effectively and safely on their own. Further, the physical training gaps between men and women should be addressed, with suggestions regarding where improvements can be made, especially for women interested in seeking combat positions with high physical demands.

The effects of cross-training on fitness and injury in women.

BACKGROUND: As combat arms occupations become available to women, adequate muscular strength and aerobic endurance will be essential for the completion of physically demanding job-related tasks. Therefore, in addition to US Army Physical Readiness Training, Soldiers will often engage in their own personal physical fitness training programs. PURPOSE: To evaluate fitness and injury outcomes for women participating in personal cross-training programs compared to women performing one mode of training or having no personal fitness program. METHODS: Demographics, physical training activities, physical fitness, and injuries were obtained from surveys administered to female Soldiers in an infantry division. Women were categorized into the following 4 groups based on their personal physical fitness program: cross-training (CT), running only (R), weight training only (WT), and no personal fitness program (NPF). An ANOVA was used to compare physical training, health behaviors, and physical fitness across groups. A χ² test was used to compare injury rates between fitness programs. Risk (%), risk ratios (RR) and 95% confidence intervals (95% CI) were used to determine injury risk. RESULTS: A total of 620 women completed the survey and indicated whether or not they had a personal fitness program (cross-training, n=260; running only, n=93; weight training only, n=86; no personal fitness program, n=181). Average age and body mass index was 26.2±5.8 years and 24.5±3.3 kg/m² respectively with no differences between the 4 fitness groups. The cross-training group had higher physical performance on the muscular endurance (push-ups and sit-ups) portion of the Army physical fitness test (APFT) when compared to the 3 other groups (CT 42 push-ups vs (R 38, WT 35, NPF 36)); (CT 68 sit-ups vs (R 63, WT 62, NPF 62)). For the aerobic endurance (2-mile run) portion of the APFT, the cross-training group had higher performance when compared to those with no personal fitness program (CT 17.4 minutes vs NPF 18.5 minutes). Overall, 53% of female Soldiers sustained an injury over a 12-month period. All injury rates and lower extremity injury rates among women with a cross-training personal fitness program were not different from the other personal fitness programs. Those performing cross-training were 2.6 and 2.1 times more likely to experience a running related injury when compared to those in the weight training and no personal fitness group, respectively. On the other hand, women performing cross-training were 65% less likely to experience a lifting/moving heavy objects related injury when compared to the weight training only group. CONCLUSIONS: Women who participated in a cross-training program for personal physical fitness training had higher muscular endurance compared to the other fitness groups and higher aerobic endurance when compared to the no personal fitness group. There were no differences for all injuries and lower body injuries between cross-training and other fitness programs. Cross-training may be the best option for improving physical fitness when compared to just one mode of fitness training.

Risk factors associated with higher body fat in US Army female soldiers.

UNLABELLED: Increased body fat among US Soldiers is a continuing challenge that contributes to increased health risks and decreased combat readiness. Factors contributing to higher body fat among US Army female Soldiers have been minimally investigated. PURPOSE: To investigate the risk factors associated with exceeding US Army body fat standards among active duty women in a light infantry brigade. Investigated risk factors include personal characteristics, physical training, physical fitness, and injury history. METHODS: Data were obtained by survey from women in 3 US Army infantry brigades. Body fat percentage was calculated, and the women were categorized as either meeting or exceeding the maximum Army body fat standard of 30% for ages 17-20, 32% for ages 21-27, 34% for ages 28-39, and 36% for age 40 years or more. Army Physical Fitness Test (APFT) results were converted into tertiles (T), where T1=lowest 1/3 of performance and T3=highest 1/3 of performance. Odds ratios (OR) and 95% confidence intervals (CI) were calculated from a multivariate analysis assessing risk associated with exceeding the Army body fat standards. RESULTS: Among the women surveyed (n=629), 22% exceeded Army body fat standards. Higher risk of being above the Army standard was associated with older age (≥29 years / ≤23 years) (OR=47, 95% CI, 1.24-4.92), and poor aerobic fitness (APFT 2-mile run) (T1/T3) OR=6.11, 95% CI, 2.62-14.24), (T1/T2) OR=2.66, 95% CI, 1.12-6.33). A marginal association was found for poor muscular strength (APFT sit-ups) (T1/T3). CONCLUSION: The results suggest that women who are older, and/or have poor aerobic fitness are more likely to exceed the maximum Army body fat standards.