Effects of Turnouts and Structure Boots on the Kinematics of Firefighters During a Drop Landing

Firefighters require the ability to perform under intense conditions involving challenging movements. Protective gear, such as turnouts and structure boots, plays an impactful role in protecting firefighters. Understanding how the gear influences movement is essential for improving their safety and performance. PURPOSE: This study aimed to analyze the effects of turnouts and structure boots on the sagittal plane ankle and knee kinematics of firefighters during a drop-landing. METHODS: Eleven healthy male firefighters participated. Retroreflective markers were attached to the subject's lower extremities to identify their anatomy and movement using a three-dimensional motion capture system. The subjects performed three drop-landing tasks from an 18-inch box to replicate getting off of a fire truck by stepping off the box, leading with their dominant leg, and landing on two force plates with both feet. Three trials were collected for each condition: (1) exercise attire and (2) turnouts and structure boots; the condition order was randomized. RESULTS: Significant findings included decreased ankle plantarflexion and increased knee flexion angles at initial contact, decreased ankle angular displacement, and decreased ankle velocity in the turnouts and boots compared to baseline exercise attire. The turnouts and structure boots trended to decrease knee angular displacement with moderate effect size. CONCLUSION: In the turnouts and boots, there was reduced ankle plantarflexion and increased knee flexion angles at initial contact which contributed to a significant decrease in total ankle displacement and velocity, possibly due to the rigid structure of the boots externally supporting the ankle joint. The boots also reduced the subject's knee displacement which was likely affected by the increased initial angle. Turnouts and structure boots were associated with a decrease in lower extremity kinematics and may shift biomechanical demands proximally. Continued repetitions of increased force demands with limited mobility imposed on firefighters can explain biomechanical changes that contribute to common back and knee injuries in firefighters. Further research is needed to analyze the effects of turnouts and boots on lower extremity kinetics as well as biomechanics of the hip and back.