Physiological and performance responses to a running in linear vs. closed track during the twelve minutes run test

Aim: The aim of this study was to compare the physiological responses and the performance of athletes during twelve minutes run test (12-MRT) on a linear track compared to a closed track. Methods: Twelve healthy men and 10 healthy women took part in a 12-MRT either on a closed track (CLO) or a linear track (LIN) in random order. In both variants, distance covered, post-exercise blood lactate concentration ([La]) and Borg scale (RPE) were measured. Results: Distance covered was not significantly different (P>0.05) between the two variants in males and females; a decrease of 6.9% vs. 5.8% in LIN compared to CLO was respectively observed in males and females. This decrease was significant (P<0.05) in subjects with high performance >(3000 m) and not significant (P>0.05) in subjects with low performance (<3000 m) in males; no significant variation (P>0.05) was observed in females whatever the performance class (<2500 m or >2500 m). There was a significant decrease of [La] (P<0.05) during the LIN compared to CLO in females. No significant difference (P>0.05) was found in RPE in males and females. A negative correlation (r=-0.62, P=0.03) was found between RPE and [La] during the LIN in females. Conclusion: It appears that the linear track limits the performance of the subjects. This might be explained by the high variability of running economy in the two halves of running time.