I’m about 99% certain that it’s because of the work week and two day weekends, but has anyone ever used another base for a training schedule?
Has anyone ever used an 8 day training cycle or a 6 day cycle? I know you’d need some job flexibility to do this, or some vacation time to take days off.
I have a friend who did a 5 day cycle once (or maybe it was a 10 day cycle) with a long run once every five days, and a long ride once every 5 days. The cycle was more like 10 days, because they didn’t do the long run and long ride in the same 5 days. They also took off just one day in the 10 day cycle. They said they had their best IM after training that way.
Most training plans revolve around a 7 day schedule due to the ease of planning like you thought. There are a number of people out there who do use different time frames though, 5, 7, 10, 14 day cycles are all ones I’ve used in the past with my athletes. Sometimes it depends on their work schedule or sometimes it depends on how much time we have to prepare before a specific event.
I recently attended a clinic at USA Triathlon and Susan Williams, Olympic medalist, described a cool 9 and 10 day cycle she had used and used with her clients. the 9 day cycle included no rest days and the 10 day cycle was off on the 10th day.