Changes in Borg scale of perceived exertion during two-hour running performance with constant velocity on treadmill ergometer
Abstract
Objectively estimated biomarkers (e.g. heart rate, lactacidemia, oxygen consumption VO2etc.) have been used to evaluate the intensity of physical load, especially in top class sport competition and training. In practice of ordinary recreational sport and other leisure-time physical activities proved useful Borg Scale of Perceived Exertion - BSPE.
In the group of 20 well trained runners the values of BSPE were registered every 15 min during 2-hour treadmill running at the intensity corresponding to 60-70 % of individual VO2max. Despite of constant workload intensity significant increase of BSPE in final half-hour of the performance was recorded.
BSPE increased from initial level at 11,5 (Light) to final 15,5 (Very hard). There were distinct inter-individual differences among the runners, related to different training programs, performance level and age of the subjects.
BSPE increase could be probably evoked by gradual loss of muscle glycogen, which during 2-h running performance undoubtedly could happen. Super-compensation of muscle glycogen with the help of training and dietary stratégy before the performance and with adequate carbohydrate supplementation could prevent the adverse symptoms of hypoglycemia and syndrome of "hitting the wallL.