If you haven’t seen it before, this might interest you. A summary of a study(*) to compare the effects of two different training regimes during off-season on performance the following pre-season.
TLDR “Including a HIT session every 7-10 days during off-season seems to prevent loss of fitness and enhance performance 16 weeks into pre-season”
(*) 1. Rønnestad et al. HIT maintains performance during the transition period and improves next season performance in well-trained cyclists. European Journal of Applied Physiology, 2014;114:1831-1839