The influence of pre-warming on the physiological responses to prolonged intermittent exercise

To examine the influence of pre-warming on the physiological responses to prolonged intermittent exercise in ambient temperatures of 21.5 +/- 0.6 degrees C and relative humidities of 35.7 +/- 5.4% (mean +/- s), six healthy men performed intermittent treadmill running (30-s bouts at 90% of maximal oxygen uptake separated by 30-s static recovery periods) to exhaustion after active pre-warming, passive pre-warming and pre-exercise rest (control). Exercise time to exhaustion was significantly different between all conditions (active, 51.8 +/- 7.2 min; passive, 38.5 +/- 11.1 min; control, 72.0 +/- 17.2 min; P < 0.05). These changes in performance time were closely associated with a significant decline in both the rate of heat storage and heat storage capacity (P < 0.05). Rectal temperature, heart rate and ratings of perceived exertion were significantly higher during exercise in the two pre-warming conditions than in the control condition (P < 0.05). Ratings of perceived exertion were also significantly higher during exercise following passive pre-warming compared with active pre-warming (P < 0.05). During exercise there were no significant differences in serum prolactin, plasma norepinephrine and plasma free fatty acid concentrations between conditions. We conclude that both active and passive pre-warming promote a reduction in prolonged intermittent exercise capacity in environmental temperatures of 21 degrees C compared with pre-exercise rest. These performance decrements were dependent upon the mode of pre-warming and closely reflected alterations in body heat content.     

Temporal changes in home advantage in English football since the Second World War: what explains improved away performance?

This study examined temporal trends in home advantage in the top two English football divisions and used change point analysis to test the hypothesis that home advantage has not remained constant over time. Regression analysis was used to model the impact of substitutions (a proxy for "information transfer") and the points system on home advantage. The results suggest that changing from two points for a win to three points for a win has led to a 0.39 reduction (95% confidence interval=0.21 to 0.56) in the ratio of home wins to away wins. Increasing the number of substitutions is associated with a small increase in the ratio of home wins to away wins, although this is not statistically significant. The evidence indicates that, in this particular context, the extent of home advantage has diminished. This contradicts most other published work, which suggests that home advantage is stable over time. I argue that this reduction is more likely to be the result of the introduction of three points for a win, which has lessened the incentives for away teams to settle for a draw, than an increase in "information transfer". Research into temporal trends in home advantage is interesting in its own right but might, in addition, shed light on determinants of the home advantage phenomenon.     

A Description of a Simple Teaching Machine

The operation of the electrical circuit of a relatively simple teaching machine, and some ways in which this machine has been used are described.