Effects of Deployment on Musculoskeletal and Physiological Characteristics and Balance.

Despite many nonbattle injuries reported during deployment, few studies have been conducted to evaluate the effects of deployment on musculoskeletal and physiological characteristics and balance. A total of 35 active duty U.S. Army Soldiers participated in laboratory testing before and after deployment to Afghanistan. The following measures were obtained for each Soldier: shoulder, trunk, hip, knee, and ankle strength and range of motion (ROM), balance, body composition, aerobic capacity, and anaerobic power/capacity. Additionally, Soldiers were asked about their physical activity and load carriage. Paired t tests or Wilcoxon tests with an α = 0.05 set a priori were used for statistical analyses. Shoulder external rotation ROM, torso rotation ROM, ankle dorsiflexion ROM, torso rotation strength, and anaerobic power significantly increased following deployment (p < 0.05). Shoulder extension ROM, shoulder external rotation strength, and eyes-closed balance (p < 0.05) were significantly worse following deployment. The majority of Soldiers (85%) engaged in physical activity. In addition, 58% of Soldiers reported regularly carrying a load (22 kg average). The deployment-related changes in musculoskeletal and physiological characteristics and balance as well as physical activity and load carriage during deployment may assist with proper preparation with the intent to optimize tactical readiness and mitigate injury risk.

The Effect of Target Position on the Accuracy of Cervical-Spine-Rotation Active Joint-Position Sense.

CONTEXT: The cervical spine can be divided into upper and lower units, each making a different contribution to the magnitude of rotation and proprioception. However, few studies have examined the effect of the cervical-rotation positions on proprioception. OBJECTIVE: To compare cervical-spine rotation active joint-position sense (AJPS) near midrange of motion (mid-ROM; 30°) and near end-ROM (60°). DESIGN: Cross-sectional study. SETTING: Human performance research laboratory. PARTICIPANTS: 53 military helicopter pilots (age 28.4 ± 6.2 y, height 175.3 ± 9.3 cm, weight 80.1 ± 11.8 kg). MAIN OUTCOME MEASURES: A motion-analysis system was used to record cervical-rotation kinematics. Subjects sat in a chair wearing a headband and blindfold. First, they actively rotated the head right or left to a target position (30°/60°), with real-time verbal cues provided by the tester. Subjects held the target position for 5 s and then returned to the start position. After this, they replicated the target position as closely as possible. Five trials were performed in both directions to both target positions (R30/R60/L30/L60). Order of direction/position was randomized. The difference between target and replicated positions was calculated and defined as absolute error (AE), and the mean of 5 trials was used for analyses. Wilcoxon signed-ranks tests were used to compare AJPS at the different target positions (P < .0125 with Bonferroni adjustments). RESULTS: End-ROM AEs were significantly more accurate than mid-ROM AEs (P = .001). CONCLUSION: Cervical-spine-rotation AJPS is more accurate near end-ROM than mid-ROM. Both target positions should be used to examine cervical-spine-rotation AJPS of both the upper and lower units.

Lumbar spine and hip flexibility and trunk strength in helicopter pilots with and without low back pain history.

BACKGROUND: Low back pain (LBP) is one of the most common musculoskeletal issues facing military helicopter pilots. It is clinically important to identify differences in musculoskeletal characteristics between pilots with and without a LBP history for formulating effective interventions. OBJECTIVE: To compare lumbar spine and hip flexibility and trunk strength in pilots with and without a LBP history. METHODS: A total of 30 pilots with a LBP history were matched with pilots without a LBP history. An isokinetic dynamometer and a digital inclinometer were used to evaluate trunk and hip strength and a range-of-motion (ROM), respectively. All tests were performed bilaterally, if applicable, and agonist/antagonist ratios and side-to-side (low/high) symmetries were calculated. Paired t-tests or Wilcoxon tests were used to assess group differences (p <  0.050). RESULTS: The LBP group demonstrated significantly lower trunk extension strength and trunk extension/flexion strength ratio (p <  0.008). The LBP group demonstrated significantly less lateral flexion ROM as well as greater lateral flexion and rotation side-to-side asymmetry (p <  0.009). The LBP group demonstrated significantly greater total hip rotation side-to-side asymmetry (p = 0.037). CONCLUSIONS: Given the results, specific exercises that are targeted to improve trunk strength, ROM, and side-to-side symmetries could be developed to reduce LBP in helicopter pilots.

Neck proprioception, strength, flexibility, and posture in pilots with and without neck pain history.

INTRODUCTION: Neck pain (NP) is common among military helicopter pilots. Older age and more flight-hours have been associated with pilots with a history of NP. However, modifiable neuromuscular and musculoskeletal characteristics such as neck proprioception, strength, flexibility, and posture have rarely been investigated in military helicopter pilots with a history of NP. The purpose of the study was to compare demographics, flight characteristics, physical fitness information, neck proprioception, strength, flexibility, and posture between helicopter pilots with and without a history of NP. METHODS: A total of 27 Army helicopter pilots with NP in the past 12 mo (pain group) were matched based on age with pilots without a history of NP (nonpain group). All pilots had flown at least 100 h in the past 12 mo and were cleared for flight and physical training. All pilots completed a battery of laboratory testing: neck proprioception, neck and scapular muscular strength, neck active range-of-motion (ROM), forward head and shoulder posture, and pectoralis minor length. Paired t-tests or Wilcoxon tests were used to compare differences between groups. RESULTS: The pain group had significantly less cervical extension (63.7 +/- 8.5 degrees) and rotation ROM (R rotation: 67.7 +/- 8.8 degrees; L rotation: 67.4 +/- 9.0 degrees) when compared to the nonpain group (extension: 68.3 +/- 7.4 degrees; R rotation: 73.4 +/- 7.4 degrees; L rotation: 72.9 +/- 6.8 degrees). No significant differences were found for other variables. CONCLUSION: 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.

Warrior Model for Human Performance and Injury Prevention: Eagle Tactical Athlete Program (ETAP) Part I.

INTRODUCTION: Physical training for United States military personnel requires a combination of injury prevention and performance optimization to counter unintentional musculoskeletal injuries and maximize warrior capabilities. Determining the most effective activities and tasks to meet these goals requires a systematic, research-based approach that is population specific based on the tasks and demands of the warrior. OBJECTIVE: We have modified the traditional approach to injury prevention to implement a comprehensive injury prevention and performance optimization research program with the 101st Airborne Division (Air Assault) at Ft. Campbell, KY. This is Part I of two papers that presents the research conducted during the first three steps of the program and includes Injury Surveillance, Task and Demand Analysis, and Predictors of Injury and Optimal Performance. METHODS: Injury surveillance based on a self-report of injuries was collected on all Soldiers participating in the study. Field-based analyses of the tasks and demands of Soldiers performing typical tasks of 101st Soldiers were performed to develop 101st-specific laboratory testing and to assist with the design of the intervention (Eagle Tactical Athlete Program (ETAP)). Laboratory testing of musculoskeletal, biomechanical, physiological, and nutritional characteristics was performed on Soldiers and benchmarked to triathletes to determine predictors of injury and optimal performance and to assist with the design of ETAP. RESULTS: Injury surveillance demonstrated that Soldiers of the 101st are at risk for a wide range of preventable unintentional musculoskeletal injuries during physical training, tactical training, and recreational/sports activities. The field-based analyses provided quantitative data and qualitative information essential to guiding 101st specific laboratory testing and intervention design. Overall the laboratory testing revealed that Soldiers of the 101st would benefit from targeted physical training to meet the specific demands of their job and that sub-groups of Soldiers would benefit from targeted injury prevention activities. CONCLUSIONS: The first three steps of the injury prevention and performance research program revealed that Soldiers of the 101st suffer preventable musculoskeletal injuries, have unique physical demands, and would benefit from targeted training to improve performance and prevent injury.

Warrior Model for Human Performance and Injury Prevention: Eagle Tactical Athlete Program (ETAP) Part II.

INTRODUCTION: Physical training for United States military personnel requires a combination of injury prevention and performance optimization to counter unintentional musculoskeletal injuries and maximize warrior capabilities. Determining the most effective activities and tasks to meet these goals requires a systematic, research-based approach that is population specific based on the tasks and demands of the Warrior. OBJECTIVE: The authors have modified the traditional approach to injury prevention to implement a comprehensive injury prevention and performance optimization research program with the 101st Airborne Division (Air Assault) at Fort Campbell, KY. This is second of two companion papers and presents the last three steps of the research model and includes Design and Validation of the Interventions, Program Integration and Implementation, and Monitor and Determine the Effectiveness of the Program. METHODS: An 8-week trial was performed to validate the Eagle Tactical Athlete Program (ETAP) to improve modifiable suboptimal characteristics identified in Part I. The experimental group participated in ETAP under the direction of a ETAP Strength and Conditioning Specialist while the control group performed the current physical training at Fort Campbell under the direction of a Physical Training Leader and as governed by FM 21-20 for the 8-week study period. RESULTS: Soldiers performing ETAP demonstrated improvements in several tests for strength, flexibility, performance, physiology, and the APFT compared to current physical training performed at Fort Campbell. CONCLUSIONS: ETAP was proven valid to improve certain suboptimal characteristics within the 8-week trial as compared to the current training performed at Fort Campbell. ETAP has long-term implications and with expected greater improvements when implemented into a Division pre-deployment cycle of 10-12 months which will result in further systemic adaptations for each variable.