Effects of marathon training on maximal aerobic capacity and running economy in experienced marathon runners.

Maximal aerobic capacity (VO) and running economy (RE) are markers of running performance. A valid evaluation of RE may occur through allometric scaling of body mass (alloVO; ml kg min), energy cost (EC; kcal kg km), or percent of VO (%VO). Little is known about physiological changes that occur in competitive runners over a marathon training cycle. The VDOT score, incorporating VO and RE, enables comparison of race performances under different temperature conditions. This study's purpose was to determine whether VO and measures of RE change with marathon training, and to evaluate the relationship between these variables and VDOT. Eight runners (age 34±2 years; marathon <3:00 males, <3:30 females; five females) completed treadmill marathon-intensity-effort (MIE) and VO tests at 10 and 1-2 weeks pre-marathon. Body composition (%BF) was determined using hydrostatic weighing. Paired t-tests were used to compare pre- and post-training values. The alpha level for significance was set at 0.05. Body fat decreased from 18.7±1.5% to 16.7±1.6%, VO increased from 51.6±2.4 to 63.9±1.1 ml kg min, and %VO during the MIE decreased from 82.1±2.0 to 72.3±3.2% (p < 0.05 for all). VDOT was significantly associated with alloVO (r = -0.779, p = 0.039) but not with VO (r = 0.071, p = 0.867). Experienced competitive runners may increase VO and decrease %BF after a marathon-specific training cycle. The decrease in %VO in a MIE is likely due to a higher VO, as other measures of RE did not change significantly. In this cohort, alloVO was negatively correlated with race performance.