M.D. Many competitive endurance athletes lift weights to make themselves stronger. A recent study from Australia shows that they may not be improving their performances.
Cycling is a power sport.
The strongest legs push hardest on the pedals to make the bike move faster. Competitive cyclists train by pedaling for hours. You train for competition by taking a hard workout, feeling sore on the next day and then training at a reduced intensity until the muscle soreness disappears. Pushing heavy weights damages the muscles much more than riding long distances. Cyclists who push heavy weights with their legs take longer to recover and cannot ride as many fast miles.