Pincao Gao, Jiatao Zhang, Fang Tang, Weiguo Liu
Relative to the FPE condition, FPE + FL and FPE + D significantly shortened step length, support duration and stride speed (p < 0.05); these indicators were also significantly lower than FPE + GC, and FPE + D further decreased support time and stride speed (p < 0.05). Compared with FPE, FPE + FL and FPE + D induced significantly larger peak hip extension and ankle dorsiflexion angles as well as elevated hip/knee joint moment, power, joint work and peak vertical ground reaction force (vGRF) (p < 0.05), whereas only ankle dorsiflexion angle significantly increased in FPE + GC (p < 0.05). All three loaded groups displayed elevated total hip work and higher hip work proportion accompanied by reduced ankle work contribution (p < 0.05). FPE + D produced remarkably greater joint work metrics than FPE and FPE + GC (p < 0.05); meanwhile, FPE + FL and FPE + D had higher hip extension moment, ankle dorsiflexion moment, knee work and peak vGRF than FPE + GC (p < 0.05).\ CONCLUSION: Firefighters shorten step length and rely on compensatory hip and knee movements to accommodate increasing external load. The ultra-heavy dummy load in FPE + D substantially increases hip and knee injury risk; targeted hip-knee strength training is recommended to reduce injury occurrence during heavy-load rescue operations.
OBJECTIVE: To investigate the lower-extremity kinematic and kinetic features of firefighters under different rescue loads and provide evidence for injury prevention in firefighting training and field rescue.
METHODS: Eleven healthy male firefighters from Guilin Fire and Rescue Department completed four experimental protocols: baseline wearing 12.5 kg firefighting protective equipment (FPE), FPE plus 15 kg gas canister (FPE+GC), FPE plus 30 kg fire ladder (FPE+FL), and FPE plus 60 kg rescue dummy (FPE+D). The Qualisys infrared motion capture system and AMTI force platform were adopted to acquire kinematic and kinetic data.
RESULTS: Relative to the FPE condition, FPE + FL and FPE + D significantly shortened step length, support duration and stride speed (p < 0.05); these indicators were also significantly lower than FPE + GC, and FPE + D further decreased support time and stride speed (p < 0.05). Compared with FPE, FPE + FL and FPE + D induced significantly larger peak hip extension and ankle dorsiflexion angles as well as elevated hip/knee joint moment, power, joint work and peak vertical ground reaction force (vGRF) (p < 0.05), whereas only ankle dorsiflexion angle significantly increased in FPE + GC (p < 0.05). All three loaded groups displayed elevated total hip work and higher hip work proportion accompanied by reduced ankle work contribution (p < 0.05). FPE + D produced remarkably greater joint work metrics than FPE and FPE + GC (p < 0.05); meanwhile, FPE + FL and FPE + D had higher hip extension moment, ankle dorsiflexion moment, knee work and peak vGRF than FPE + GC (p < 0.05).\ CONCLUSION: Firefighters shorten step length and rely on compensatory hip and knee movements to accommodate increasing external load. The ultra-heavy dummy load in FPE + D substantially increases hip and knee injury risk; targeted hip-knee strength training is recommended to reduce injury occurrence during heavy-load rescue operations.