Do you find that you feel better or produce better results in training or racing during the afternoon or early evening? Or do you like to get out bright and early and get the race over with? The former makes you an 'owl', and the latter a 'lark'. But even if you reckon you're a morning-type lark, chances are you will still perform better in the evening, according to a study by a group led by G. Atkinson of the Research Institute for Sport and Exercise Science at Liverpool John Moores University.

They asked eight male cyclists to perform 10-mile time-trials at 7:30am on one day, and 5:30pm on another. On each day, the cyclists got out of bed at 0600, and performed exactly the same 25-minute warm-up immediately before each ride.

By administering a 'chronotype' questionnaire, the investigators found that all eight cyclists reported themselves as 'larks'. However, the mean performance time was quicker in the evening (1415 seconds in the morning, compared with 1366 seconds in the evening) in spite of he self-selected preference for exercising in the morning. The difference cannot be explained by an increased body temperature in the afternoon, because the 25-minute warm-up raised body temperature in the morning to the same level as that in the afternoon.

These findings may go some way to explaining why Chris Boardman was successful in his hour record attempt at 7:00pm, whereas Miguel Indurain was not successful when he cycled at 6:00am - a time that was chosen to optimise environmental conditions, but perhaps not physiological conditions.

The moral of the story is that athletes should try to choose evening races when they want a PB, and race organisers should move away from early-morning starts.

Creatine works on inactive muscles as well
The effects of creatine supplementation on performance during competition and on strength gains during training have been well documented, not least in PP. Creatine delays fatigue and allows higher power outputs to be achieved. Results from a new study led by B. Op't Eijnde at the August Krogh Institute in Denmark show that creatine may even benefit inactive muscles.

Twenty-two subjects volunteered to have their right leg put in a cast for two weeks, during which time half of them took creatine (group C) and the other half a placebo (group P). Before and after immobilisation, maximal knee extension strength, muscle cross-sectional area and muscle creatine-phosphate concentrations were measured.

Both groups showed similar decreases in muscle strength and size over the two weeks of immobilisation. However, during a subsequent 10-week rehabilitation programme, group C showed a greater increase in muscle size and strength returning to pre-immobilisation levels earlier than group P. This was attributed to a decrease in muscle creatine phosphate concentrations within the muscle fibres for group P whereas group C maintained their levels.

The authors concluded that oral creatine supplementation reduces the functional deterioration of muscles during disuse. Thus creatine could be used as a therapeutic measure to maintain muscle strength for people whose muscles weaken for reasons such as breaking a limb or getting old.

Stephen Garland