Another sprint / interval study

low volume sprints and high volume intervals have the same effect in terms of this aspect of gene expression......so why spend time doing doing the long stuff?

Mitochondrial gene expression in elite cyclists: effects of high-intensity interval exercise

Little is known about the effect of training on genetic markers for mitochondrial biogenesis in elite athletes. We tested the hypothesis that low-volume sprint interval exercise (SIE) would be as effective as high-volume interval exercise (IE). ............... We conclude that upstream genetic markers of mitochondrial biogenesis increase in a similar way in elite athletes after one exercise session of SIE and IE. However, since the volume and duration of work was considerably lower during SIE and since Tfam, the downstream target of PGC-1alpha, increased only after SIE, we conclude that SIE might be a time-efficient training strategy for highly trained individuals.