GROUND REACTION FORCE ANALYSIS OF THE YOUNG AND ELDERLY GAIT ON THE INFLUENCE OF THE OVERWEIGHT SIMULATION

ABSTRACT The aim of this study was to evaluate the ground reaction forces (FRS) in young and old individuals under the influence of simulated overweightin differents gait speeds. Method: 30 participants, 15 young (YNG; 22±3.7 years) and 15 older adults (OA; 69.8±6.4 years) walked on a walkway with and without an additional load. The simulation of overweight occurred through the addition of load in a variable load vest until reaching the body mass index (BMI) of overweight (BMI YNG 25kg/m²; OA 27kg/m²). FRS were measured using an force platform (AMTI, OR6-7-2000). Results: The mean load to produce an overwight status was 13.2 ± 4.0 kg for young and 11.7 ± 3.4 kg for older adults. The significant level adopted was p≥0,05. When normalizing by body weight, the OA presented lower FRS peaks in comparison to YNG group at both speeds. On the other hand, the OA presented higher second peak of the vertical force (Fz2) in the fast speed condition in comparison to the YNG. Conclusion: Directly simulated overweight may not be able to promote significant changes in the unload quantities, arising from bodyweight, that may influence the FRS.

摘要：本研究旨在评估不同步态速度下模拟超重对青年与老年个体地面反作用力（ground reaction forces, FRS）的影响。方法：共招募30名受试者，其中15名青年受试者（YNG；22±3.7岁）及15名老年受试者（OA；69.8±6.4岁），分别在附加负重与无负重状态下于步道上行进。超重模拟通过穿戴可变负重背心直至达到超重体重指数（body mass index, BMI）阈值：青年组目标BMI为25kg/m²，老年组为27kg/m²。地面反作用力采用测力台（AMTI, OR6-7-2000）进行采集。结果：青年组达到超重状态所需平均负重为13.2±4.0kg，老年组为11.7±3.4kg。本研究采用的显著性检验水准为p≥0.05。以体重进行归一化处理后，两种步态速度下老年组的地面反作用力峰值均低于青年组。但在快速步态条件下，老年组的垂直力第二峰值（Fz2）高于青年组。结论：直接通过负重模拟超重，或许无法对源自体重的负荷量产生显著改变，而该负荷量可能会对地面反作用力造成影响。