Aerobic Exercise Adaptations Of Summer-training In Well-trained Male And Female Adolescent Distance Runners

Abstract

1414 Maximal oxygen uptake (VO2max) and running economy (RE) are important determinants of endurance running performance. In preparation for a competitive cross-country season, most high-school athletes train during the summer months. However, the effects of this form of endurance training on VO2max and RE are largely unknown. PURPOSE: This study examined alterations in VO2max and RE along with submaximal blood lactate concentration ([BLa]) before (Pre) and after (Post) summer training in a group of well-trained high school runners. METHODS: Seven females (15.8 ± 1.1yrs) and 11 males (17.0 ± 0.9 yrs) underwent treadmill testing. Submaximal exercise responses were measured during steady-state exercise at 7.0 and 8.0 mph, and VO2max was measured by a graded exercise test to exhaustion. Data was collected 2–3 weeks after the subjects' competitive track season at the onset of summer training (Pre), and 1–2 weeks prior to the first competitive cross-country meet (Post). The data were analyzed using repeated measures ANOVA's. RESULTS: Pre and Post VO2max data in males was 70.9 ± 3.5 and 72.9 ± 4.5 ml/kg/min. In females VO2max was 57.9 ± 5.1 and 57.1 ± 4.6 ml/kg/min during the same two testing periods. The interaction and time effects were not significant; however, VO2max in males was greater (p < 0.05) than in females. Pre RE at 7.0 and 8.0 mph was 40.9 ± 2.5 and 46.4 ± 2.7 ml/kg/min in males and 40.7 ± 1.9 and 46.2 ± 1.9 ml/kg/min in females, respectively. Post RE at 7.0 and 8.0 mph decreased (p < 0.05) and was 40.4 ± 2.5 and 45.8 ± 2.8 ml/kg/min in males and 39.8 ± 2.9 and 44.9 ± 3.4 ml/kg/min in females, respectively. Differences between gender and all interactions were not significant. At 7.0 mph [BLa] in males were 1.7 ± 0.3 mmol/L Pre and 1.9 ± 0.4 mmol/L Post. At 8.0 mph [BLa] was 1.8 ± 0.3 mmol/L Pre and 1.7 ± 0.5 mmol/L Post. In females, [BLa] at 7.0 mph were 2.2 ± 0.5 and 1.8 ± 0.3 mmol/L in Pre and Post, respectively. At 8.0 mph [BLa] in females was 3.4 ± 1.1 mmol/L Pre and was 2.7 ± 0.7 mmol/L Post. [BLa] was lower (p < 0.05) in males, decreased over time (p < 0.05) with the decrease from Pre to Post being greater in females than males (p < 0.05). CONCLUSIONS: Pre-season distance running does not appear to increase VO2max in high-school cross-country runners, but does improve RE. The change in [BLa] from Pre to Post was greater in females, however the lack of change in males was most likely attributed to their extremely low initial [BLa] levels and higher level of fitness. Supported by the Office of Academic Research and Sponsored Programs at Ball State University and the Gatorade Sports Science Institute