You’ve heard that long, slow rides are crucial in the early season because they build capillaries in your working muscles. This approach sounds reasonable because cycling power depends on the delivery of oxygen-rich blood to your quads. The more capillary density you have, the more oxygen is available to power your muscles.
But you’re confused by the other part of this “go slow” training prescription. Namely, that you should avoid all intense efforts for the first 3 months of base building because any anaerobic work will destroy the newly created capillaries, thus negating all the progress you’ve made. Harder efforts, some coaches argue, should be postponed until after you’ve totaled at least 2,000 miles of easy spinning at the beginning of the season.
So what’s the real deal?
Much research has been done about whether slow, high-volume training builds capillaries, and whether increased capillaries improve performance. For the latter point, the evidence is pretty firm. The more capillaries you have, the higher your VO2 max and potential for endurance activities. Weight lifters have capillary density no greater than sedentary folks, but endurance athletes have plentiful capillaries to carry more oxygen to working cells.
As for whether extensive slow training builds more capillaries, it’s difficult to get a direct answer. But we know that capillarization is proportional to VO2 max. The higher your oxygen uptake, the more capillaries you have. So workouts that increase VO2 max are the best workouts to increase capillaries.
And guess what sort of workouts produce the biggest gains in VO2 max? Not slow miles but rather moderately long rides with relatively fast interval training included. The old adage that intense workouts are the best producer of top fitness is still valid.
There’s nothing wrong with doing long, slow rides in the off-season. But they shouldn’t be your only mode of training. Keep the intensity going, and you’ll be that much farther ahead come the heart of the season.
It can be as simple as adding intensity during slow rides. Your fast efforts don’t have to be reserved for hard or long training days. When you’re on an easy recovery ride, try throwing in 3 sprints at about 90% effort. Simply get out of the saddle in a moderate gear, accelerate for 10 seconds and then spin until you’re back to your cruising speed. Don’t go all-out. Instead, think about fluid and relaxed speed. You’ll be amazed at how these “pick ups” will reinvigorate you on slow rides — and add a touch of speed to your legs, too.
Coach Fred Matheny is an RBR co-founder who has four decades of road cycling and coaching experience. He has written 14 eBooks and eArticles on cycling training, available in RBR’s eBookstore at Coach Fred Matheny, including the classic Complete Book of Road Bike Training, which includes 4 eBooks comprising 250 pages of timeless, detailed advice and training plans. The Complete Book is one of the many perks of an RBR Premium Membership. Click to read Fred’s full bio.