It all depends whether your expecting to be needing that type of fitness anytime soon? If you like doing them they are fine to do every now and then to blow the cobwebs away but they probably shouldn't be a staple this early in the season. Probably strength and endurance building sessions would be more suitable right now. If you like doing that sort of session though 6-8 weeks out from needing that race specific fitness start doing them a couple of times a week. To incorporate them into a plan and actually build fitness rather than just doing that same session over and over try to build on it by either adding a rep or making the loop a little longer or even reducing the recovery by either making it shorter or upping the intensity of easier stretches in your loop every week to form a progression.
It all depends whether your expecting to be needing that type of fitness anytime soon? If you like doing them they are fine to do every now and then to blow the cobwebs away but they probably shouldn't be a staple this early in the season. Probably strength and endurance building sessions would be more suitable right now. If you like doing that sort of session though 6-8 weeks out from needing that race specific fitness start doing them a couple of times a week. To incorporate them into a plan and actually build fitness rather than just doing that same session over and over try to build on it by either adding a rep or making the loop a little longer or even reducing the recovery by either making it shorter or upping the intensity of easier stretches in your loop every week to form a progression.