Background: In order to improve neuromuscular and biomechanical characteristic deficits in female athletes, numerous injury prevention programs have been developed and have successfully reduced the number of knee ligament injuries. However, few have investigated the neuromuscular and biomechanical changes following these training programs. It is also largely unknown what type of program is better for improving the landing mechanics of female athletes. Objectives: To investigate the effects of an 8 week plyometric and basic resistance training program on neuromuscular and biomechanical characteristics in female athletes. Methods: Twenty seven high school female athletes participated either in a plyometric or a basic resistance training program. Knee and hip strength, landing mechanics, and muscle activity were recorded before and after the intervention programs. In the jump-landing task, subjects jumped as high as they could and landed on both feet. Electromyography (EMG) peak activation time and integrated EMG of thigh and hip muscles were recorded prior to (preactive) and subsequent to (reactive) foot contact. Results: Both groups improved knee extensor isokinetic strength and increased initial and peak knee and hip flexion, and time to peak knee flexion during the task. The peak preactive EMG of the gluteus medius and integrated EMG for the gluteus medius during the preactive and reactive time periods were significantly greater for both groups. Conclusions: Basic training alone induced favourable neuromuscular and biomechanical changes in high school female athletes. The plyometric program may further be utilised to improve muscular activation patterns.

Based on the evidence of higher risk of MSK injuries after concussion, standard clinical assessments for athletes with concussion should include not only physical symptoms and cognitive function before return to sport but also neuromuscular risk factors associated with increased risk for MSK injuries.

Purpose Quadriceps weakness is a common clinical sign following anterior cruciate ligament injury and reconstruction surgery (ACLR). The aim of this study was to compare strength deficits and the limb symmetry index (LSI) from three different types of functional tests: isokinetic dynamometry, hop test, and leg press. Methods A total of 26 subjects with ACLR (average 8.3 months post-operation) participated in the study. The peak knee extension torque was tested with isokinetic dynamometry at 60/180/300 °/s (ISO60/180/300). Hop distance was tested during single hop (SH) and triple hop (TH). Unilateral peak leg power (POWER) was tested during a bilateral leg press test. LSI was calculated as the ratio of the involved limb over the uninvolved limb values. Pearson correlation coefficients and paired t-tests were used to establish relationships among ISO60/180/300, SH/TH, and POWER values and compare these values between the limbs, respectively. Within-subject one-way analysis of variance (ANOVA) with post hoc analyses was used to compare LSI values among different tests. Results ISO60/180/300 values were significantly positively correlated with SH/TH and POWER (P < 0.05), while SH/TH and POWER values were not significantly correlated. Significant limb differences were found in all tests (P = 0.001-0.008). ANOVA revealed significant LSI differences among different tests. Specifically, post hoc analyses revealed that LSI during SH was significantly higher than LSI during ISO60. Similarly, LSI during TH was significantly higher than LSIs from ISO60, ISO180, and POWER tests. Conclusions Peak knee extension torque values were positively associated with hop distance and leg power during the leg press test. However, LSI values should be interpreted with caution as hop tests provided significantly higher LSI values than isokinetic testing. Both isokinetic dynamometry and unilateral leg press machine could be used to isolate and strengthen the quadriceps in the involved limb. The current "gold standard" isokinetic testing at slow speed (ISO60) provided the lowest LSI value among all functional tests; therefore, the current study supported a continued use of isokinetic testing when examining individual's readiness and return-to-sport. Level of evidence III.

The purpose of this study was to compare physical and physiological fitness test performance between Soldiers meeting the Department of Defense (DoD) body fat standard (< or = 18%) and those exceeding the standard (> 18%). Ninety-nine male 101st Airborne (Air Assault) Soldiers were assigned to group 1: < or = 18% body fat (BF) or group 2: > 18% BE. Groups 1 and 2 had similar amounts of fat-free mass (FFM) (66.8 +/- 8.2 vs. 64.6 +/- 8.0, p = 177). Each subject performed a Wingate cycle protocol to test anaerobic power and capacity, an incremental treadmill maximal oxygen uptake test for aerobic capacity, isokinetic tests for knee flexion/extension and shoulder internal/external rotation strength, and the Army Physical Fitness Test. Results showed group 1: < 18% BF performed significantly better on 7 of the 10 fitness tests. In Soldiers with similar amounts of FFM, Soldiers with less body fat had improved aerobic and anaerobic capacity and increased muscular strength.

The results demonstrate less neck active ROM in pilots with a history of NP. Operating a helicopter with limited neck ROM or NP may negatively impact flight safety and force readiness. Continued research is warranted.

The additional weight of combat and protective equipment carried by soldiers on the battlefield and insufficient adaptations to this weight may increase the risk of musculoskeletal injury. The objective of this study was to determine the effects of the additional weight of equipment on knee kinematics and vertical ground reaction forces (VGRF) during two-legged drop landings. We tested kinematics and VGRF of 70 air assault soldiers performing drop landings with and without wearing the equipment. Maximum knee flexion angles, maximum vertical ground reaction forces, and the time from initial contact to these maximum values all increased with the additional weight of equipment. Proper landing technique, additional weight (perhaps in the form of combat and protective equipment), and eccentric strengthening of the hips and knees should be integrated into soldiers' training to induce musculoskeletal and biomechanical adaptations to reduce the risk of musculoskeletal injury during two-legged drop landing maneuvers.

The purpose of this study was to evaluate the nutrient intake of male and female Soldiers in the 101 st Airborne Division (Air Assault) compared to sports nutrition standards for athletes, and to identify suboptimal eating characteristics that may impair physical performance and jeopardize military readiness. Male and female Soldiers from the 101 st Airborne Division (Air Assault) completed a 24-hour dietary recall and nutrition history questionnaire before anthropometric and body composition measurements were taken. Compared to sports nutrition guidelines, Soldiers of the 101 st under consume carbohydrates (males: 3.9 ± 2.0 vs. 5.0 g/kg, p < 0.001; females: 4.0 ± 2.1 vs. 5.0 g/kg, p = 0.001), male Soldiers eat too much fat (32.4% of kcal vs. <30% of kcal, p = 0.000) and saturated fat (males: 10.5 ± 3.9% of kcal vs. 10.0% of kcal, p = 0.044), and both males and females follow a meal pattern that may not optimize energy availability throughout the day. Eating too much fat and under fueling carbohydrate may negatively impact the adaptations to physical training and compromise overall health. Although Soldiers continue to participate in arduous training programs, future research should be aimed at determining the energy and macronutrient needs to fuel and recover from specific types of military training.

Poor postural stability has been identified as a risk factor for lower extremity musculoskeletal injury. The additional weight of body armor carried by Soldiers alters static postural stability and may predispose Soldiers to lower extremity musculoskeletal injuries. However, static postural stability tasks poorly replicate the dynamic military environment, which places considerable stress on the postural control system during tactical training and combat. Therefore, the purpose of this study was to examine the effects of body armor on dynamic postural stability during single-leg jump landings. Thirty-six 101st Airborne Division (Air Assault) Soldiers performed single-leg jump landings in the anterior direction with and without wearing body armor. The dynamic postural stability index and the individual stability indices (medial-lateral stability index, anterior-posterior stability index, and vertical stability index) were calculated for each condition. Paired sample t-tests were performed to determine differences between conditions. Significant differences existed for the medial-lateral stability index, anterior-posterior stability index, vertical stability index, and dynamic postural stability index (p < 0.05). The addition of body armor resulted in diminished dynamic postural stability, which may result in increased lower extremity injuries. Training programs should address the altered dynamic postural stability while wearing body armor in attempts to promote adaptations that will result in safer performance during dynamic tasks.