Threshold Intervals (Bike)

Threshold Intervals on the bike are sustained hard efforts that raise the power you can hold for longer periods. They train your legs, lungs, and aerobic system to work right at the edge of what you can maintain.

Set up on a road bike, spin bike, or indoor trainer. Adjust the saddle so your leg has a slight bend at the bottom of each pedal stroke. Sit firmly on the saddle, hands on the hoods or drops, and keep your torso steady. Use cycling shoes or firm athletic shoes with the straps snug.

After an easy warm-up, start the first interval at your tested threshold power. Pedal smoothly at a controlled cadence, keep your upper body quiet, and aim to hold the same effort across the whole block. Spin easy between intervals, then repeat for the prescribed number of blocks. Finish with easy spinning to cool down. Treat this as your one key bike quality session for the week and keep hard days separated with easy recovery days.

Breathe in a steady rhythm and keep a light brace through your midsection to support your torso without holding your breath. Easier option: shorten the work blocks or add more recovery. Harder option: lengthen the work blocks or reduce the recovery, but only if your form stays smooth and controlled.

Fault: Starting too hard and fading before the interval ends. Fix: Begin conservatively and hold the same effort from start to finish; the last few minutes should feel hard but still controlled.

Fault: Grinding at a very low cadence to hit the power target. Fix: Keep a comfortable, quick pedal stroke; if you have to muscle the pedals slowly, lower the resistance or power and rebuild from there.

Fault: Doing threshold bike sessions on consecutive days or right next to a hard run. Fix: Place these intervals on a fresh day, separate hard sessions with easy days, and never stack this back-to-back with your key run day.