Effects of leg fatigue due to exhaustive stair climbing on gait biomechanics while walking up a 10° incline – Implications for evacuation and work safety. (July 2021)

• Record Type: Journal Article
• Authors: Halder, Amitava; Nordin, Axel; Miller, Michael; Kuklane, Kalev; Nirme, Jens; Gao, Chuansi
• Is Part Of: Fire safety journal. Volume 123(2021)
• Publication Date: 2021-07
• Subjects: Whole body exhaustion -- Localized muscle fatigue -- Human locomotion -- Accidents and injuries -- Incline walking gait biomechanics -- Required coefficient of friction -- Kinetics -- Kinematics -- Ground reaction force -- Electromyography; Fire prevention -- Periodicals; Incendies -- Prévention -- Recherche -- Périodiques; Fire prevention -- Research; Periodicals; 628.92205
• DOI: 10.1016/j.firesaf.2021.103342
• Languages: English
• ISSNs: 0379-7112

Abstract

Abstract: This biomechanics study explored stride length (SL), stride duration (SDN), the peak of gait ground reaction forces (GRFspeak ), required coefficient of friction (RCOFpeak ), joints' angle (anglepeak ), angular velocity (angvelx peak ), angular acceleration (angaccx peak ), minimum angle (anglemin ) of foot, and muscle electromyography (EMG) during the dominant leg stance phase (SP) following an exhaustive stair ascent for evacuation. Data were collected by a three-dimensional motion capture system synchronized with EMG and force plate when walking upwards on a 10° inclined walkway. The significantly ( p ≤ .05) decreased EMG median frequencies of tibialis anterior during early (ES) and late stance (LS) phases, and vastus lateralis muscles during LS are the evidence of leg local muscle fatigue (LMF). The perpendicular and longitudinal shear GRFspeaks were significantly reduced during ES ( p ≤ .05 ) and LS ( p ≤ .01 ), respectively. The post-fatigue SP, SL, and SDN were significantly (p < .05) shorter. Specially, the foot anglemins, ankle anglepeaks, and relevant angvelx peaks, and angaccx peaks significantly ( p ≤ .05 ) decreased in post-fatigue trials. The post-fatigue RCOFpeaks were found significantly ( p ≤ .01 ) lower during LS phase. Thus, whole body exhaustion and leg LMF constrained the gait kinetics and kinematics when walking upwards indicating a cautious gait associated with the risks of falls, accidents, which can hinder the process of evacuation and work safety on slopes. Highlights: Post exhaustion walking showed local muscle fatigue (LMF) of the major thigh and lower leg muscles evidenced by decreased EMG median frequencies. Whole body exhaustion and fatigue shorten the stance phase, stride length, and stride duration when walking up a 10° inclined walkway. Leg LMF decreases the ground reaction forces, ankle, and foot relative angles indicating an unstable and perturbed gait upwards on an incline. Post-fatigue gait up an incline results in a lower required coefficient friction associated with risks for fall accidents when working on slopes. Fatigue induced altered gait up an incline can hinder the process of evacuation and contribute to more accurate modeling of evacuation behavior.