(40) DO ACTIVE-DUTY AIR FORCE MEMBERS WITH RECENT LOWER BODY INJURY PROFILES DEMONSTRATE LOWER FORCE PLATE JUMP PERFORMANCE?

Active-duty military members are particularly susceptible to injury and/or chronic pain due to repetitive nature of their operational duties/requirements. Jump assessments on portable force plate systems have become increasingly popular for identifying movement patterns and neuromuscular capabilities, particularly those that place individuals at greater risk for sustaining an injury. Although the primary purpose of these assessments is to guide rehabilitation and strength and conditioning program strategies, it is important to identify which assessments are influenced by individualistic features such as prior injury.

Purpose: Evaluate whether force plate jump assessments differ between active-duty Air Force members who have and have not incurred a recent lower body musculoskeletal injury/pain profile.

Methods: As part of a larger initiative by the Air Force Research Laboratory’s Movement Matters project, 706 active-duty Air Force members completed a battery of movement assessments. Participants completed surveys to identify whether they had experienced any musculoskeletal pain or sustained a musculoskeletal injury to the lower body, resulting in an injury profile within the 6 months prior to evaluation. Jump assessments consisted of three maximal effort arm-swing countermovement jumps (ASCMJ), no arm-swing countermovement jumps (CMJ), loaded CMJs with a weighted vest (6, 8, or 10 kg), and drop jumps from 30 cm box (DJ), in that order, on dual force plates. The mean of the three trials were compared between Pain (N= ~75) and No-Pain (N=~624) groups using independent samples T-tests with Benjamini & Hochberg p-value corrections and effect sizes (ES).

Results: No ASCMJ metrics were different between Pain and No-Pain groups (Table 1). During CMJ, there was a small difference between Pain and No-Pain for Peak Landing Force Relative to Jump Height, but not Jump Height (Table 1) or other metrics. All LCMJ metrics were different between groups (Table 1). The No-Pain group, during DJ, had a deeper Countermovement Depth, higher Jump Height, less Passive Stiffness, and less Peak Drop Landing Forces (Table 1).

Conclusions: Metrics from ASCMJ were not different for Air Force members with recent musculoskeletal related injury profiles. However, landing forces were higher for the Pain group during the CMJ, LCMJ, and DJ assessments. Although other CMJ metrics did not differ between groups, movement strategies and performance outcomes during the LCMJ and DJ were poorer for the Pain group. PRACTICAL APPLICATIONS: Musculoskeletal injury or pain that result in injury profiles may influence the ability to perform more difficult jump maneuvers, such as landing tasks and moving under load. This information is important for informing assessment selection for military populations, as determining return to work status may be dependent on operational demands.  

Acknowledgements: This work is part of a larger congressionally funded project titled “Movement Matters” out of the Signature Tracking for Optimized Nutrition and Training (STRONG) Lab under the Air Force Research Laboratory’s 711th Human Performance Wing.