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

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.


Autor / Fonte:Thomas Edwards, J P Barfield, Grace M Niemiro, Joseph W Beals, Elizabeth M Broad, Robert W Motl, Michael De Lisio, Nicholas A Burd, Lara A Pilutti Spinal Cord Series and Cases 2018, 4: 77
Link: https://www.nature.com/articles/s41394-018-0114-3