The need to carry different items, which become an extra load, is a characteristic of trail running. The aim of this study is to determine physiological-metabolic changes produced by running with extra load. Four male well-trained trail runners completed three treadmill maximal metabolic tests carrying different loads (0% (L0), 5% (L5), and 10% (L10) of their body mass) in a weighted vest. Gasses exchange was monitored to assess ventilatory thresholds 1 (VT1), and 2 (VT2), zone of maximal fat oxidation, and peak oxygen consumption (VO2peak). Heart rate (HR), power and velocity (V) were tracked for comparing their behavior. A repeated measures ANOVA showed significant differences in V (p<.001; ηp2= 0.910) as a limitation for reaching peak velocity (Vpeak) with L10 respect to L0 (p=0.001), and L5 (p=0.011). Power expression showed differences (p=0.068; ηp2= 0.592). It tended to be greater with L10 than L0 (p=0.057), despite achieving lower V. VT2 tended to occur at different %VO2peak (p=0.069; ηp2= 0.591). L5 VT2 was reached at higher %VO2peak than L0 (p=0.062), and L10 (p=0.071). ANOVA also showed a tendency to signification for V at this point (p= 0.098; ηp2= 0.538). In conclusion, L10 seems to limit Vpeak while L5 may delay VT2 expression.

2S-hesperidin is a flavanone (flavonoid) found in high concentrations in citrus fruits. It has an antioxidant and anti-inflammatory effect, improving performance in animals. This study investigated the effects of chronic intake of an orange extract (2S-hesperidin) or placebo on aerobic-anaerobic and metabolic performance markers in amateur cyclists. A double-blind, randomized, placebo-controlled trial was carried out between late September and December 2018. Forty amateur cyclists were randomized into two groups: one taking 500mg/day 2S-hesperidin and other taking 500 mg/day placebo (microcellulose) for 8 weeks. All participants completed the study. Performance and metabolic aerobic-anaerobic markers were measured using incremental and rectangular tests by indirect calorimetry. The anaerobic power was determined using Wingate tests. After 8 weeks supplementation, there was a significant increase in the incremental test in estimated functional threshold power (FTP) (3.23%; p≤0.05) and maximum power (2.68%; p≤0.05) with 2S-Hesperdin compared to placebo. In the rectangular test, there was a significant decrease in VO₂ (-8.26%; p≤0.01) and VO₂R (-8.88%; p≤0.01) at VT2 in placebo; however, there were no significant differences between groups. In the Wingate test, there was a significant increase (p≤0.05) in peak and relative power in both groups, but without significant differences between groups. Supplementation with an orange extract (2S-hesperdin) 500mg/day improves estimated FTP and maximum power performance in amateur cyclists.

In the last decade there has been a growing interest in infrared thermography in the field of sports medicine in order to elucidate the mechanisms of thermoregulation. The aim of this study was to describe bilateral variations in skin temperature of the anterior thigh and patellar tendon in healthy athletes, to provide a model of baseline tendon and muscle thermoregulation in healthy sprinters following a unilateral isokinetic fatigue protocol. Fifteen healthy national-level sprinters underwent unilateral isokinetic force testing and electrostimulation in which body temperature was measured before, during, and after the protocol using an infrared thermographic camera. ANOVA detected a significant difference in the time x side interaction for patellar temperature changes (p≤0.001) and a significant difference in the time x side interaction for quadriceps temperature changes (p≤0.001). The thermal challenge produces homogeneous changes evident in quadriceps areas, but not homogeneous in tendon areas. these data show that metabolic and blood flow changes may depend on the physical and mechanical properties of each tissue.