Open AccessEffect of functional fatigue on vertical ground reaction force among individuals with flat feet
Author(s) -
Boozari Sahar,
Jamshidi Ali Ashraf,
Sanjari Mohammad Ali,
Jafari Hassan
Publication year - 2012
Publication title -
journal of foot and ankle research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.763
H-Index - 39
ISSN - 1757-1146
DOI - 10.1186/1757-1146-5-s1-p5
Subject(s) - barefoot , ground reaction force , medicine , context (archaeology) , repeated measures design , biomechanics , force platform , foot (prosody) , physical medicine and rehabilitation , gait , physical therapy , muscle fatigue , electromyography , mathematics , anatomy , kinematics , geology , paleontology , linguistics , statistics , philosophy , physics , classical mechanics
CONTEXTFlat foot is one of the lower extremity deformities that might change kinetic variables of gait. Fatigue is one of the factors that can alter the vertical ground-reaction force (GRF). The effect of a fatiguing condition on vertical GRF has not been documented in individuals with flat feet.OBJECTIVETo examine the fatigue effect on vertical GRF in individuals with flat feet compared with a normal group during barefoot walking.DESIGNRepeated-measure ANOVA for the effects of fatigue on individuals with flat feet and normal feet.SETTINGBiomechanics laboratory.PARTICIPANTS17 subjects with flat feet and 17 normal subjects (recruited according to their arch-height ratio).MAIN OUTCOME MEASURESThree vertical GRF measures (F1, the first peak force; F2, minimum force; and F3, the second peak force) were extracted before and after a functional fatigue protocol.RESULTSNo significant interaction between fatigue and group was observed for the 3 vertical GRF measures. For F2, fatigue and group effects were significant (P = .001 and P = .02, respectively). Furthermore, F2 was higher in the flat-feet group than in the normal group; F2 also increased after fatigue. For F3, only a significant fatigue effect was observed (P = .004). F3 decreased after fatigue in both groups.CONCLUSIONSIn the flat-feet group, a decrease in the variation of vertical GRF might be due to more flexible foot joints. After fatigue, muscles might lose their ability to control the foot joints and cause higher F2 in the flat-feet group.