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Updated: Feb 23, 2026

Paradigms of Lower Extremity Electrical Stimulation Training After Spinal Cord Injury

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Exercise-related sensations contribute to decrease power during repeated cycle sprints with limited influence on

Olivier Girard^1,2, François Billaut³, Ryan J Christian^4,5

¹Athlete Health and Research Performance Center, Aspetar Orthopaedic and Sports Medicine Hospital, Doha, Qatar. oliv.girard@gmail.com.

European Journal of Applied Physiology

|August 31, 2017

Summary

Severe hypoxia increases exercise sensations and fatigue during repeated sprints, but quadriceps neural drive remains unaffected. Performance decline is linked to heightened perceptions, not reduced neural output, in known tasks.

Keywords:

Central fatigue Hypoxia Overall perceived exertion Perceptual cues Repeated-sprint ability

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Published on: June 8, 2017

Area of Science:

Exercise Physiology
Sports Science
Human Performance

Background:

Understanding the physiological and perceptual responses to exercise under varying oxygen availability is crucial for optimizing training and performance.
Repeated sprint protocols are common in athletic training, and their effects can be modulated by environmental factors like hypoxia.

Purpose of the Study:

To investigate the impact of manipulated inspired oxygen fraction (FiO2) on exercise sensations and quadriceps neural drive during repeated maximal cycle sprints.
To determine if physiological perturbations under hypoxia alter the neural control of muscle activity during fatiguing exercise.

Main Methods:

Nine active males performed a 10 x 4-second maximal cycle sprint protocol with 30-second passive recovery.
Experiments were conducted under normoxia (FiO2 0.21) and severe normobaric hypoxia (FiO2 0.13).
Measurements included peak power, quadriceps Root Mean Squared electromyography (RMS EMG), heart rate, arterial oxygen saturation, blood lactate, and perceptual responses.

Main Results:

Severe hypoxia led to lower arterial oxygen saturation and higher blood lactate levels compared to normoxia.
Exercise-related sensations were significantly greater (~36%) in hypoxia.
Mean power output was reduced (-13%) and sprint decrement was more pronounced (21.4% vs. 13.2%) in hypoxia, despite a consistent 17% decrease in RMS EMG from the first to the last sprint, independent of oxygen condition.

Conclusions:

Severe hypoxia exacerbates physiological and perceptual responses during repeated sprints, but the performance decrement is not associated with a greater decline in quadriceps neural drive (RMS EMG).
These findings suggest that heightened exercise-related sensations or perceptions, rather than reduced neural output, contribute to fatigue during repeated sprinting when task characteristics are predictable.