IS THE POST-LUNCH DIP IN SPRINTING PERFORMANCE ASSOCIATED WITH THE TIMING OF FOOD INGESTION

To detect whether the drop in performance around lunch has any direct association with the time of food ingestion, a group of 8 sprinters we re studied for 5 consecutive Saturdays. On each testing day, the times achieved during 80 meter sprints performed at eight different times o f the day separated by 2 hour intervals were recorded. The Ist and 4th testing days, had identical sleep and mealtime schedules, and were th erefore considered ''control days'', while on the 2nd and 3rd resting days the schedule was brought forward (''advanced'') or backward (''de layed'') by 2 hours respectively. On the 5th testing day the sleep-wak e cycle was brought forward 2 hours without changing the mealtime sche dule. A post-lunch dip (PLD) was detected on all testing days although at different times. No significant differences in performance were ob served between days 1 and 4 while there were differences in performanc e during the other testing days. It is worth pointing out that PLD occ urred at about 15:00 h on the control days, with significant differenc es between the 2nd (p < 0.05) and 3rd days (p < 0.05), and with the de terioration in performance starting at 15:00 h on the 3rd day despite the fact that lunch had been served at 16:00 h. In conclusion, PLD doe s not appear to be directly linked to the time of lunch, although lunc h itself could potentiate its effects. It is also worth mentioning the fact that this deteriorating effect does not occur after any other me als of the day.