Many riders rightly observe that riding hills is more challenging than riding flats and then wrongly interpret that to mean they should ride hills on the majority of their rides. Riding hills can be a useful part of a road, MTB, crit or century training plan, but not to the exclusion of flats. In fact, one or two days per week in hills is plenty, even for riders specifically preparing for hilly events. More is detrimental. Several times we've seen huge improvements in fitness when riders shifted their training grounds from mostly hills to mostly ...