We investigated the physiological consequences of one of the most extreme exercises realized by humans in race conditions: a 166-km mountain ultra-marathon (MUM) with 9500 m of positive and negative elevation change. For this purpose, (i) the fatigue induced by the MUM and (ii) the recovery processes over two weeks were assessed. Evaluation of neuromuscular function (NMF) and blood markers of muscle damage and inflammation were performed before and immediately following (n = 22), and 2, 5, 9 and 16 days after the MUM (n = 11) in experienced ultra-marathon runners. Large maximal voluntary contraction decreases occurred after MUM (−35% [95% CI: −28 to −42%] and −39% [95% CI: −32 to −46%] for KE and PF, respectively), with alteration of maximal voluntary activation, mainly for KE (−19% [95% CI: −7 to −32%]). Significant modifications in markers of muscle damage and inflammation were observed after the MUM as suggested by the large changes in creatine kinase (from 144±94 to 13,633±12,626 UI L−1), myoglobin (from 32±22 to 1,432±1,209 µg L−1), and C-Reactive Protein (from (2.0 to 37.7±26.5 mg L−1). Moderate to large reductions in maximal compound muscle action potential amplitude, high-frequency doublet force, and low frequency fatigue (index of excitation-contraction coupling alteration) were also observed for both muscle groups. Sixteen days after MUM, NMF had returned to initial values, with most of the recovery process occurring within 9 days of the race. These findings suggest that the large alterations in NMF after an ultra-marathon race are multi-factorial, including failure of excitation-contraction coupling, which has never been described after prolonged running. It is also concluded that as early as two weeks after such an extreme running exercise, maximal force capacities have returned to baseline.
F.02 Acquisition of new scientific knowledge
COBISS.SI-ID: 4010161OBJECTIVE: The objective was to examine the tracking of obesity from childhood to young adulthood in Slovenia. SUBJECTS: A subsample included 4833 children from the Slovenian national sample (n 21 777) who were included in the SLOFIT monitoring system from 1997 to 2008, with complete data at 7 years and 18 years. DESIGN: A 12-year prospective cohort study. Height, weight and triceps skinfold thickness (TSF) were measured at 7, 11, 14 and 18 years. The BMI cut-off points of the International Obesity Taskforce were used to identify excess weight and obesity. SETTING: The survey was conducted in Slovenian primary and secondary schools from 1988 to 2008 but only the data from the measurements in 1997, 2001, 2004 and 2008 are presented. RESULTS: Height, weight and BMI at 18 years were well predicted from childhood and became more predictable with age, while TSF was not. Obese and overweight children had the greatest risk of becoming obese or overweight young adults. The history of their weight shows that 40.0 % of males and 48.6 % of females who were obese at 18 years had already been obese at 7 years. CONCLUSIONS: Overweight or obese Slovenian children are more likely to become overweight or obese adolescents and young adults than reported in other similar European and American studies, which indicates the need for early prevention and treatment of excess weight and obesity.
F.02 Acquisition of new scientific knowledge
COBISS.SI-ID: 3979697The aim of the review was to present experimental results performed in the past 3 years in the Laboratory of Biodynamics. These results have brought to a novel point of view on alpinist adaptations influenced by climbing to (acclimatization) and descent from (deacclimatization) high-altitude expedition. Alpinists were tested before and after expeditions in normoxic and hypoxic conditions. The reduction of body weight, which accompanied alpinists during high-altitude expedition, affects some other parameters because of the increased relative energetic expenditure for the same absolute work. Heart rate (HR) increased its values. However, because of possible simultaneous influence of training, which influences HR in opposite direction (decrease), values not show adaptation, probably due to masking of the phenomenon. Ventilation is parameter, which was affected by high-altitude hypoxia and reduced body weight in the same direction. Why increased VE observed during testing in normoxic conditions after high-altitude expedition was not observed also during testing in hypoxic conditions is not known. Arterial oxygen saturation is still elevated after a month of deacclimatization during testing in hypoxia. This was effect of acclimatization. Better oxygenation of arterial blood and brain was not found after a three weeks of deacclimatization from high-altitude expedition. However, it seems that a certain level of enhanced oxygenation persisted in exercising leg muscles. Local muscle oxygenation seems to be important during climbing at all. We observed forearm muscles oxygenation and found that muscles have been more oxygenated in trained alpinists and less in untrained.
F.02 Acquisition of new scientific knowledge
COBISS.SI-ID: 3787441