This is a good program for the deep of winter for goal-oriented athletes with minimal time for training. The total hours don't exceed 8 per week and the TSS around 450-550 and we go for 1 session per day (or 2 short sessions done together). Doing the program in a consistent fashion will keep you around the 60s in CTL.
My one-on-one athletes will do this level of training through the winter and ramp up in the spring and summer to bigger weeks of 600-800tss (9-12hrs) with a volume focus and we shoot for a CTL of 80-100 for thier big events. This block is meant to support the volume block coming through the strength and core sessions and the harder threshold riding. We hope to increase our FTP during this phase and then hold it through volume phase so that in the end our IM or half IM effort will be at a reasonable % of an improved FTP, with enough volume and strength that we can run a strong marathon/half marathon afterwards.