Maximal anaerobic (lactic) capacity and power of the horse.

Blood lactate concentrations were determined in 16 horses (three Thoroughbreds, seven Standardbreds and six polo ponies) before and 5 mins after they galloped over distances of 200, 300 and 400 m at maximal speed. The highest net lactate concentration (delta Lamax) of 14 to 15 mmol/litre was attained by the polo ponies and the highest speed by the Thoroughbreds. The maximal rate of lactate production (delta Låmax) was about 35 mmol/litre X min for the polo ponies and 20 to 25 mmol/litre X min for the Standardbreds and the Thoroughbreds. Values for delta Lamax and delta Låmax were similar to those measured in human athletes after exhaustive work. delta Låmax increases with the speed (v) and can be described by the equation delta Lå = a (v-v1), where a is a proportionality constant representing the amount of lactate needed to cover a unit distance and v1 the theoretical speed at which delta Lå = 0 X v1 was highest for the Thoroughbreds and lowest for the polo ponies; this difference could be caused by the effect of training and/or to genetic differences among the different breeds of horses X v1 could be a useful index of the fitness of a horse following a training programme.

Energy sources in alpine skiing (giant slalom).

The energy cost of a giant slalom event was measured in eight skiers of national level. The lap lasted on average 82 s. VO2 was measured during the first, the second and the last third of the lap in different trials and also during recovery from a complete lap. Blood lactate was measured at the end of a lap. From the data obtained it was possible to calculate that: a) VO2, as measured during the lap, would correspond at steady state to 80% of the VO2max of the subjects; b) the total metabolic power delivered during the lap should be equal to about 72 ml O2 X kg-1 X min-1, corresponding to 120% of VO2max of the subjects. Considering the short duration of the trial and the power output delivered during maximal efforts on a bicycle ergometer, it appears that the giant slalom is not a very high energy demanding event.