AJS914 wrote: ↑Tue May 07, 2019 9:42 pm
I think the key is to first build the base.
I saw an interesting post in a much older thread, where a poster said any kind of riding (including intervals or Z3/4/5 riding) contributes to base. While technically this is true, at harder efforts your body is making entirely different adapations (again cited in an earlier post in this thread), such as maximum oxygen capacity (i.e., Vo2Max as opposed to oxygen efficiency) and lactate threshold. Several posters in this thread went on to dismiss Z2 efforts as "junk miles" and a waste of time, or that base building is an outdated mode of training. The funny thing is, the hype around interval training really began in the 1970s, starting in the USA. Shortly following this trend, the USA has suffered several decades of poor performance at elite endurance sports, falling far behind Africa and Europe, despite very high participation rates and funding rates relatively speaking. So in fact, the focus on a lot of intervals and fast training is actually decades old, and has had spotty success. The proponents of hard training refer to "base" in nebulous terms, without ever going into detail about what is achieved in Zone 2 (in the 5 zone system).
Very recent studies (past 3-10 years) have shown that Zone 2 is nearly as effective at increasing your Vo2Max as interval training over the same time period, and that short sprints (SIIT) is just as, if not more effective, at increasing neuromuscular responses and muscular strength than interval training (HIIT). In terms of capillarization and production of mitochondria, Zone 2 is the most effective.
So when we talk about "building base," I think people really need to understand what that means. It means building capillaries and mitochondria so your cardiovascular system can more efficiently utilize oxygen (use less) to produce power through your existing muscles. And when we talk about "adding speed," we are really talking about (1) building more muscle fibers, (2) learning to develop further efficiencies (more biomechanical and neruomuscular) at higher power outputs and (3) improving your body's ability to remove and process lactate.
Vo2Max is something that is achieved equally in Zone 2 or higher thresholds. The reason why people recommend Vo2Max specific training (i.e., shorter interval reps) is because it is believed to be more time efficient. Yes, it is, but that's only half the story. By doing Vo2Max specific training, for most amateurs you really need to take it easy the day before and a day or two after for recovery, so you lose out on 3, maybe even 4 days of quality aerobic training because you end up doing recovery training to compensate for that one Vo2Max session. But yes, time spent in Vo2Max training in shorter when doing intervals, but is it really worth it? For a highly trained elite athlete, they can recover faster, and don't need to take it so slow the day before or the days after, so as a fine-tune before an event, yes it is worth it. But for the average amateur? I'd say 3-4 quality Zone 2 rides for 120 minutes with a few short sprints thrown in throughout is much more effective than 1 really hard (and shortish) Vo2Max session for 45 minutes (not counting the literal junk warmup and cooldown minutes, although the rest between sets is beneficial from an aerobic perspective since your HR remains elevated) preceded by a Zone 2 ride the day before and easy recovery rides the day (or two) afterwards.
"Sweet spot" attempts to merge these types of training and honestly, for an amateur it seems promising. But it's very new, and there's not a lot of science behind it (yet), so I'm very reluctant to recommend this over the proven holistic system used by elite endurance athletes, which is a lot of slow miles with speed and weight training sprinkled in. The British and GCN seem to love "sweet spot" though!
