For decades, many investigations have been focused on the production and removal of lactate in relation to exercise (see for example, Van Hall et al. 2002, Draper et al. 2006). During intense exercise, lactate is produced faster than the ability of the tissues to remove it, and thus lactate concentration begins to rise. Recovery process plays an essential role in determining subsequent athletic performance
Athletes are running, swimming, and skating faster, jumping higher, throwing further, and lifting more than ever before. Records in many events continue to be broken, and in some events the pace is accelerating. For example, in just the past five years the world record in the men's 10,000 meters has been broken eight times by six different runners. Even more startling, the world record improved by nearly three percent during this period, whereas during the preceding 30 years it improved by less than two percent!
Many factors are contributing to this improvement. Coaches have increased their knowledge base because of advances in sport medicine and science. Equipment changes have led to immediate improvements, the most recent example being the clap skate in speedskating. However, it is generally accepted that the most important cause of improved performance is the training that athletes undergo, particularly for events that require endurance or superior physical conditioning.
As records have progressed, so has the level of training. Some sport scientists estimate that training loads have increased by 20% over the past decade, and far greater increases have been noted for some sports (Weltman et al .1979).
However, there is a limit to an athlete's capacity to endure and adapt to intense training. Once this threshold is crossed the athlete fails to adapt and performance declines. Ten to twenty percent of athletes who train intensively may fall prey to the overtraining syndrome, otherwise known as staleness (Kuipers, 1998; Krieder et al. 1997).