Level 1: Active Recovery

“Easy spinning” or “light pedal pressure”, i.e., very low level exercise, too low to induce significant physiological adaptations. Minimal sensation of leg effort/fatigue. Requires no concentration to maintain pace, and continuous conversation is possible. Typically used for active recovery after strenuous training days (or races), between interval efforts, or for socializing.

Level 2: Endurance

“All day” pace, or classic long slow distance (LSD) training. Sensation of leg effort/fatigue generally low, but may rise periodically to higher levels (e.g., when climbing). Concentration generally required to maintain effort only at highest end of range and/or during longer training sessions. Breathing is more regular than at level 1, but continuous conversation still possible. Frequent training sessions of moderate duration (e.g., 2hrs) at level 2 are possible (provided dietary carbohydrate intake is adequate), but complete recovery from very long workouts may take more than 24 hours.

Level 3: Tempo

Typical intensity of fartlek workout, ’spirited’ group ride, or briskly moving paceline. More frequent/greater sensation of leg effort/fatigue than at level 2. Requires concentration to maintain alone, especially at upper end of range, to prevent effort from falling back to level 2. Breathing is deeper and more rhythmic than level 2, conversation is somewhat difficult, but not as challenging as at level 4. Consecutive days of level 3 training is still possible if duration is not excessive and dietary carbohydrate intake is adequate.

Level 4: Lactate Treshold

Just below to just above Time Trial effort, taking into account duration, current fitness, environmental conditions, etc. Essentially continuous sensation of moderate or even greater leg effort/fatigue. Conversation is difficult, due to depth/frequency of breathing. Effort is sufficiently high that sustained exercise at this level is mentally very challenging. For this reason it is typically performed in training as multiple ‘repeats’, ‘modules’, or ‘blocks’ of 10-30 min durations. Consecutive days of training at level 4 is possible, but such workouts are generally only performed when sufficiently rested/recovered from prior training sessions to be able to maintain intensity.