Here are several workouts to build on-bike strength.
Caution The workouts described below are difficult sessions and can be stressful to your knees. Monitor your knees carefully and stop if you feel any pain or discomfort. Build up the number of repeats and duration of each repeat gradually over weeks. Injuries are often caused by too much, too soon. Have patience with yourself to see the best improvements.
Big Gear Repeats On a flat course or indoor trainer pedal in a big gear, with a cadence of 50–60 rpm for 5 minutes. Your heart rate should stay in heart rate zones 2-3. That is below lactate threshold. This workout is to stress your muscular system, not aerobic system. Start with repeats of 5 minutes and work gradually up to 20 minutes. Stay seated in the saddle with a quiet upper-body throughout the repeat.
Big Gear Hill Repeats When you have built up to 20 minutes of big gear repeats on flat terrain you can do the same session on a hill to build additional strength. Remember to stay seated in the saddle with a quiet upper-body. Focus on leg strength.
Force Repeats This workout is similar to lifting weights in the gym, but done on the bike. On a flat course or indoor trainer pedal in a gear that only allows you to reach 50–60 rpm. While remaining seated drive the pedals down as hard as possible for 15–20 revolutions of the cranks. Do 6–10 of these, starting a new one every 3–4 minutes. Between force repeats spin 85+ rpm easily with light pressure on the pedals.
90 Second Hills On an indoor trainer with a high resistance setting pedal for 30 seconds at 70–80 rpm with your heart rate in zone 2-3, shift up one gear and maintain cadence for 30 seconds, shift up another gear and maintain cadence for another 30 seconds. Your heart rate will rise but should stay below lactate threshold in zones 4. Spin at 85+ rpm with light pressure on the pedals for 90 seconds recovery between each repeat. Do this 8 – 12 times.