Abstract
In recent years, mountain ultra-marathons have become increasingly popular and are considered a model to investigate physiological responses to extreme exercise load. This study aimed to investigate cardiorespiratory fitness of amateur mountain ultra-marathon runners and to characterize biochemical changes during the single-stage ultrasky-race South-Tyrol, which comprised a short (68km, 4260m elevation-gain) and a long (121km, 7554m elevation-gain) competition. Eleven male finishers (age:42.4±8.8yr) of the short and seven male finishers (age:41.0±10.2yr) of the long race were studied. One week before the race athletes performed a treadmill-running test to exhaustion. Before and after the race venous blood was collected and fluid intake was registered during the race. Athletes’ maximal oxygen uptake (VO2max) was 57.9±5.8ml/min/kg. Overall race time was 686±124 and 1,649±203min for the short and long competition, respectively. VO2max and the ventilator threshold were inversely related to race time of the short (r=-0.764 and r=-0.782, p<0.05) but showed no correlation with the long race (r=-0.179 and r=-0.357, p>0.05). Fluid intake per hour was 612.4±187.6 (short) and 422.3±198ml/h (long). Body-weight decreased during both competitions (-2.3±1.0 and -2.1±1.6kg, for the short and long, respectively). Increased WBC (+9.8±3.2 and+9.3±1.5 10³/µL), CK (+1,562±1,250 and +4,933±3,760U/l), IL6 (+49.1±19.7 and 59.5±57.3pg/ml) and ROS (+0.034±0.010 and +0.032±0.013, for short and long, respectively) were found after both competitions. Results outline the high physiological stress imposed by both contests. Interestingly, VO2max and the ventilator threshold were related to competition time only during the short race indicating that with increasing competition length other factors (e.g., pain threshold, pacing, nutrition) determine race outcome.