The examination of mental toughness, sleep, mood and injury rates in an Arctic ultra-marathon.

There is scarcity of research examining the physiological and psychological effects of ultra-endurance racing on athletes in extreme conditions. The purpose of the current study was to identify common injury patterns and illness, profile mood states and sleep patterns and finally examine the relationships between mental toughness, sleep, mood and injury rates during a 120 mile, three-day Arctic ultra-marathon. Twelve participants (3 females, 9 males) with a mean age of 42 ± 5.35 yrs participated in the study. Mental toughness was measured using the MT18 questionnaire. Injuries were clinically assessed and recorded each day. Temperatures ranged from -20 to -6 degrees Celsius throughout the race. Sleep quantity and mood state were recorded using the BRUMS questionnaire. 10 out of the 12 participants experienced injuries; almost half of the participants had injuries that carried over a number of days. Mean sleep duration over the three days was 4.07 h, with an average of 0.78 injuries per day. Significant changes in mood were recorded across the three days, specifically a reduction in vigour (p = .029) and increase in fatigue (p = .014). Neither sleep quantity nor mental toughness was correlated with injury rate. Interestingly, sleep quantity was not related to changes in mood, as previously shown in ultra-marathons. Mental toughness had a moderate negative correlation (p < 0.01) with depression (-.623), reduced anger (-.616), confusion (-.558), increased vigour (.497) and tension (-.420) during the race. Success in this type of event involves significant psychological and physiological preparation to minimize the effects of sleep deprivation and avoidance of injuries.

The effect of the branched-chain amino acids on the in-vitro activity of bovine intestinal alkaline phosphatase.

Branched-chain amino acids (BCAA) are used as nutritional support for patients with a range of conditions including liver cirrhosis and in-born errors of amino acid metabolism, and they are commonly used "sports" or exercise supplements. The effects of the BCAA on the in-vitro activity of calf intestinal alkaline phosphatase (EC. 3.1.3.1) were studied. All three BCAA were found to be uncompetitive inhibitors of the enzyme with L-leucine being the most potent ( = 24.9 mmol/L) and L-valine, the least potent ( = 37 mmol/L). Mixed BCAA are able to act in combination to inhibit the enzyme. Given the important role of intestinal alkaline phosphatase in gut homeostasis, these findings have potential implications for those taking high levels of BCAA as supplements.