Limitations of oxygen uptake and leg muscle activity during ascending evacuation in stairways

Amitava Halder, Kalev Kuklane, Chuansi Gao, Michael Miller, Mattias Delin, Johan Norén, Karl Fridolf

Research output: Contribution to journalArticlepeer-review

12 Citations (SciVal)

Abstract

Stair ascending performance is critical during evacuation from buildings and underground infrastructures. Healthy subjects performed self-paced ascent in three settings: 13 floor building, 31 floor building, 33 m stationary subway escalator. To investigate leg muscle and cardiorespiratory capacities and how they constrain performance, oxygen uptake (VO2), heart rate (HR) and ascending speed were measured in all three; electromyography (EMG) in the first two. The VO2 and HR ranged from 89-96 % of the maximum capacity reported in the literature. The average highest VO2 and HR ranged from 39-41 mL·kg-1·min-1 and 162-174 b·min-1, respectively. The subjects were able to sustain their initial preferred maximum pace for a short duration, while the average step rate was 92-95 steps·min-1. In average, VO2 reached relatively stable values at ≈37 mL·kg-1·min-1. EMG amplitudes decreased significantly and frequencies were unchanged. Speed reductions indicate that climbing capacity declined in the process of fatigue development. In the two buildings, the reduction of muscle power allowed the subjects to extend their tolerance and complete ascents in the 48 m and 109 m high stairways in 2.9 and 7.8 minutes, respectively. Muscle activity interpretation squares were developed and proved advantageous to observe fatigue and recovery over time.
Original languageEnglish
Pages (from-to)52-63
Number of pages11
JournalApplied Ergonomics
Volume66
DOIs
Publication statusPublished - 2017 Aug 30

Subject classification (UKÄ)

  • Transport Systems and Logistics
  • Production Engineering, Human Work Science and Ergonomics
  • Physiology
  • Sport and Fitness Sciences

Keywords

  • Physical capacity
  • Stair climbing
  • Oxygen consumption
  • Electromyography
  • Muscle fatigue

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