Single-Leg Balance Impairments Persist in Fully Operational Military Special Forces Operators With a Previous History of Low Back Pain

BACKGROUND: Single-leg balance (SLB) can be chronically impaired after low back pain (LBP). Impaired SLB is a risk factor for recurrent LBP and lower extremity injury. In the United States military, the special forces operator (SFO) deploys on high-risk missions under extreme conditions, and impaired SLB can potentially threaten SFO safety and mission success. PURPOSE: To compare SLB in fully operational SFOs with and without a history of LBP. The hypothesis was that SLB deficits would be present in SFOs with a history of LBP. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: A total of 226 SFOs were included in this analysis. Comparisons were made between SFOs with and without medical chart documented history of LBP (LBP group [n = 43]: mean age = 31.2 ± 10.3 years, mean height = 177.3 ± 7.2 cm, mean mass = 87.3 ± 11.8 kg; healthy group [n = 183]: mean age = 28.0 ± 6.0 years, mean height = 177.9 ± 6.0 cm, mean mass = 84.9 ± 8.8 kg). Bilateral SLB was tested (eyes open and eyes closed) in both groups using a force plate. The variability in the ground-reaction forces was averaged across 3 trials for each leg for both conditions. Comparisons were made between legs in the LBP and between the LBP and healthy group (α = .05). RESULTS: There were significant between-group differences for each leg for both conditions, with the healthy group demonstrating better SLB compared with the LBP group. P values ranged from .01 to .03. CONCLUSION: Impaired SLB persists in SFOs with previously reported LBP. Balance assessments of individuals who report LBP may assist with designing targeted interventions to address potential deficits that may increase the risk of future injury. CLINICAL RELEVANCE: SFOs with a known history of LBP would benefit from examination of SLB and may benefit from balance training to resolve any deficits that may be present to lower the potential risk for future injury.