Physical Performance Measures of Flexibility, Hip Strength, Lower Limb Power, and Trunk Endurance in Healthy Navy Cadets: Normative Data and Differences Between Sex and Limb Dominance.

ABSTRACT: Lopes, TJA, Simic, M, Alves, DdS, Bunn, PdS, Rodrigues, AI, Terra, BdS, Lima, MdS, Ribeiro, FM, Vilão, P, and Pappas, E. Physical performance measures of flexibility, hip strength, lower limb power, and trunk endurance in healthy navy cadets: Normative data and differences between sex and limb dominance. J Strength Cond Res 35(2): 458-464, 2021-The objectives were to provide normative data on commonly used physical performance tests that may be associated with musculoskeletal injuries in Navy cadets and assess for sex and limb dominance differences. A large cohort of Navy cadets were assessed for physical performance tests of flexibility (ankle dorsiflexion range of motion and sit and reach), isometric hip strength, lower limb power (single-leg hop), and trunk endurance (plank and side plank tests). Besides providing normative data tables, sex and limb dominance differences were assessed by a 2-way mixed analysis of variance. A total of 545 Brazilian Navy cadets (394 men) representing 79% of the cadets in the Academy participated. Normative reference values were reported as mean ± SD, 95% confidence interval and percentiles. For tests of muscle strength, power, and endurance, men performed better than women (p < 0.001). For flexibility tests, women achieved greater distances than men for the sit and reach test (p < 0.001), but no difference for ankle dorsiflexion (p = 0.51). Overall, there were no clinically relevant differences between limbs. In conclusion, normative data for commonly used physical performance tests were provided. Although no clinically relevant side-to-side differences were found, men presented higher values for lower limb strength and power, as well as trunk endurance than women, whereas women demonstrated increased flexibility. Valuable normative data are provided to professionals who work with young, active populations from the injury prevention or rehabilitation perspective because the current study may help professionals to identify athletes or cadets whose performance is outside the normative values and may be at risk for injury.

Trunk endurance, posterior chain flexibility, and previous history of musculoskeletal pain predict overuse low back and lower extremity injury: a prospective cohort study of 545 Navy Cadets.

OBJECTIVE: To investigate predictors of low back and lower extremity musculoskeletal injury in a cohort of Naval cadets. DESIGN: Prospective Cohort Study METHODS: 545 Naval cadets (Males, n = 394, 72%) were followed-up over eight months. Nine variables were investigated as predictors: history of musculoskeletal symptoms in the last 12 months, ankle dorsiflexion range of motion, sit and reach test, isometric hip abduction and external rotation strength, alignment during the single leg squat test, single leg hop test for distance, prone plank and side plank tests. All injuries that required medical attention were registered. Predictive associations were examined using univariable and multivariable logistic regression analyses. RESULTS: The incidence of all injuries was 7%. Cadets who failed the 60-second plank test (OR = 3.3; 95% CI, 1.2-8.8, P = 0.04), had ≤18 cm in the sit and reach test (OR = 4.0; 95% CI, 1.4-11.2, P = 0.01), or reported pain in the last 12 months in two or more body regions (OR = 2.7; 95% CI, 1.02-7.3, P = 0.04), had greater odds of sustaining an overuse injury. No predictors were identified for acute injuries. CONCLUSION: Decreased trunk endurance on the prone plank test, reduced posterior chain flexibility on the sit and reach test, and a history of pain reported in two or more sites in the last 12 months were predictors of overuse injuries in Naval cadets. Assessment and intervention of these modifiable risk factors may be clinically relevant in injury screening and prevention.

Prevalence of Musculoskeletal Symptoms Among Brazilian Merchant Navy Cadets: Differences Between Sexes and School Years.

BACKGROUND: Musculoskeletal disorders are common among military personnel, especially during the initial basic training period. Prior studies have reported the prevalence rate of overall musculoskeletal symptoms or injuries in different military population and nationalities, especially from North America and Europe; however, very limited information regarding the military population of South America exists. Although Brazil has one of the biggest military forces worldwide (≈335,000 military personnel), currently, to our knowledge, there is no study reporting musculoskeletal symptoms or injury statistics in the Brazilian Armed Forces. Thus, the aims of this study were to describe the 12-month prevalence rate of self-reported musculoskeletal symptoms in cadets and to compare this prevalence rate between sexes and school years. METHODS: We conducted a cross-sectional study that took place from January to March 2016. Participants were Navy cadets, of both sexes and from three different school years of a Brazilian Merchant Navy Academy. All volunteers completed an adapted version of the Brazilian Nordic Musculoskeletal Questionnaire that assessed the past 12-month prevalence of musculoskeletal symptoms over eight body regions of the trunk and lower extremity. The Pearson's χ2 test was conducted to compare prevalence of symptoms per body region between sexes and among the 3 school years. The study has been approved by the Naval Hospital's ethical committee. RESULTS: A total of 545 cadets (394 males), corresponding to 79% of all 688 cadets enrolled at the Merchant Navy Academy, volunteered to participate on this study. Among all cadets, 266 (49%) reported symptoms in at least one body region in the past 12-months. The knee with 116 (21%) and lower back with 96 (18%), were the most prevalent regions. In terms of sex differences, there was higher prevalence of symptoms among females 90 (60%) than males 176 (45%). Furthermore, females reported almost double the prevalence for lower back symptoms (27% vs. 14%, p = 0.001) and 11% higher prevalence of knee symptoms (29% vs. 18%, p = 0.006) than males. Finally, it is important to highlight that cadets from the second (127 [65%]) and third (77 [55%]) school years had higher prevalence of symptoms than cadets from the first year (62 [29%]). The knee and lower back were consistently the two most prevalent regions among all school years, but shin symptoms increased from 3% to 17% (p < 0.001) between the first and second school years. CONCLUSION: The prevalence of musculoskeletal symptoms in the Brazilian Merchant Navy Academy doubles between initial enrollment and the beginning of the second school year. Females have consistently higher rates of symptoms than males, particularly reporting higher prevalence of knee and lower back pain which are the two most prevalent regions in this population. Prevention efforts should concentrate on the basic training period in an attempt to decrease the prevalence of musculoskeletal symptoms in this population. Finally, prospective studies are required to verify the cause and effect relationship between training and musculoskeletal symptoms.