Thomas Edwards1, J P Barfield2, Grace M Niemiro3, Joseph W Beals3, Elizabeth M Broad4, Robert W Motl5, Michael De Lisio1,6, Nicholas A Burd3, Lara A Pilutti6,7. 1. 1School of Human Kinetics, University of Ottawa, Ottawa, ON Canada. 2. 2School of Health Sciences, Emory and Henry College, Emory, VA USA. 3. 3Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Urbana, IL USA. 4. US Olympic Committee, Chula Vista, CA USA. 5. 5Department of Physical Therapy, University of Alabama at Birmingham, Birmingham, AL USA. 6. 6Brain and Mind Research Institute, University of Ottawa, Ottawa, ON Canada. 7. 7Interdisciplinary School of Health Sciences, University of Ottawa, Ottawa, ON Canada.
Abstract
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.
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.