pre-competition

Cycling time triallists gain a significant performance advantage if, on the day before competition, they train at exactly the same time as the competition is scheduled to start. That is the important conclusion of a new study from the UK.

Eight male recreational cyclists completed two separate 16.1k time trials on cycle ergometers at 7am. On the day before one of the trials, they performed a submaximal workout at 60% VO2max for 30 minutes at 7am; on the day before the other, they performed exactly the same workout at 12 noon.

Heart rate, power output, ratings of perceived exertion and rectal temperature were measured during the exercise sessions and the time trials, and blood samples were taken before and after the time trials to measure lactate concentration.

The results showed an indisputable influence of time of day:

• The cyclists completed the time trial 34 seconds faster after the 7am submaximal exercise bout – 27mins 52secs compared with 28mins 26secs after the noon bout;
• The time trial after exercise at 7am was associated with higher work rates, a higher net lactate accumulation afterwards and a trend for higher heart rates compared to the time trial after exercise at noon.

The researchers concluded that: ‘The decrease in time to completion of the time trial (about 2%) is similar to that reported for other factors, such as training schedules and some ergogenic aids such as caffeine and represents a valuable improvement in performance, by a very simple non-invasive and cheap alteration in the preparation the day before a cycling competition in the morning.’

They also put forward three possible explanations for their findings:

1. Differences in the amount of fatigue produced by the two bouts of submaximal exercise and the effects on muscle glycogen levels of the additional recovery time after early morning exercise;
2. Early morning exercise, combined with exposure to light, might have advanced the circadian phase of body temperature, such that it started higher on the day of the time trial, offering a performance benefit;
3. Having a final practice the day before competition at exactly the same time as the competition itself confers some advantage due to familiarisation.

Further research is needed to distinguish between these possibilities. But in the meantime there are important implications for cyclists: ‘An exercise session at the appropriate time of day before competing might help to give him/her a competitive edge and be incorporated as part of the final preparations for an important event.’

Int J Sport Med 2005;26:651-656