Eustache;
Thanks for writing into the forum and thanks again for attending the Chamonix workshop. Your’s is a nearly impossible request. There is no way to plan and build progression into a training plan when your available time is erratic. Steve and I work have spent a lot of time trying to come up with a realistic solution to this problem. So far we have not.
BUT and this is important to understand. While professional athletes and those looking to maximize their own personal potential have to adhere to the types of models of progression and consistency that we advocate, amateurs must always accept some compromise. But those compromises do not need to be the end of fitness gains for you. Keep the major ideas in mind about accumulating volume in aerobic zones. Keep the big picture of strength training (targeting muscular endurance in the end) in mind and forget about a long term progression that is an impossibility in your life. Use short term planning. If you get a chance to go big one week then take it but try to use the next week as a recovery week to let that bog week soak in.
Neither Steve nor I no longer have time to ‘train’. I have to exercise somewhat similarly to you, erratically and with less progression than I know is ideal. But I can keep my base fitness fairly high and from time to time toss in some big days. It works well enough for us and I think it can work for you too.
Scott