Physiological responses during a 25-km time trial in elite wheelchair racing athletes

• Published in: Spinal cord series and cases 2018-08, Vol.4 (1), p.77-7, Article 77
• Main Authors: Edwards, Thomas, Barfield, J. P., Niemiro, Grace M., Beals, Joseph W., Broad, Elizabeth M., Motl, Robert W., De Lisio, Michael, Burd, Nicholas A., Pilutti, Lara A.
• Format: Article
• Language: English
• Subjects: 692/698/1671/1668/1973; 692/698/1688/1366/1823; Anatomy; Biomedical and Life Sciences; Biomedicine; Exercise intensity; Human Physiology; Laboratories; Metabolism; Neurochemistry; Neuropsychology; Neurosciences; Wheelchairs
• ISSN: 2058-6124; 2058-6124
• DOI: 10.1038/s41394-018-0114-3

Study Design: Observational study. Objectives: To characterize the cardiorespiratory and metabolic response of elite wheelchair racing (WCR) athletes during a 25 km, field-based time trial. Settings: University laboratory and field racing course in Urbana, Illinois, USA. Methods: Seven elite WCR athletes (4 men/3 women) with spinal cord injury completed an incremental exercise test to exhaustion on a computerized wheelchair roller system to determine peak cardiorespiratory capacity in the laboratory. The athletes then completed a long-distance, field-based time trial (i.e., 25 km) within 5 days. Energy expenditure was measured continuously during the time trial with a portable metabolic unit. Blood samples were collected to determine blood lactate and glucose concentrations. Core temperature was measured using an ingestible sensor thermistor. Results: Five participants completed the long-distance time trial with usable cardiorespiratory data. Median heart rate and oxygen consumption during the time trial was 93.6% and 76.6% of peak values, respectively. Median energy expenditure was 504.6 kcal/h. There was a significant increase in blood lactate concentration from 0.7 to 4.0 mmol/L after the time trial ( p  = 0.03). There were no changes in blood glucose concentrations after the time trial ( p  = 0.27). Lastly, core temperature significantly increased from 37.1 at baseline to 38.7 °C immediately after the time trial ( p  = 0.01). Conclusions: Elite WCR athletes sustained a high exercise intensity that was consistent across the long-distance time trial, and exercise intensity outcomes were generally lower than those documented for elite able-bodied long-distance athletes in other studies. Our findings provide accurate estimates of energy expenditure that can be used to design effective training and racing strategies for elite WCR athletes.