Interval Progression Strategies
Building interval workouts is only the first step — progressing them over weeks and months is what drives fitness gains. There are four main progression levers: increase the number of repetitions (e.g., 4×800m → 5×800m → 6×800m), increase the interval duration while maintaining pace, decrease rest periods between intervals, or increase the target pace. Only change one variable at a time — adjusting two simultaneously risks overtraining. A proven 4-week cycle: Week 1 introduces the workout at moderate effort, Week 2 adds one repetition, Week 3 reduces rest by 15–30 seconds, and Week 4 is a deload with fewer reps at easy pace. For VO2max intervals (3–5 minutes at 95–100% max HR), research suggests 2–3 sessions per week during a focused block of 4–6 weeks yields the greatest improvement. Threshold intervals (10–20 minutes at lactate threshold) respond well to volume increases — start with 2×10 minutes and build toward 3×15 minutes over 6 weeks. Always include a proper warm-up of 10–15 minutes before intervals, and a cool-down of at least 5 minutes afterward. The workout builder lets you export these structured sessions directly to Garmin devices for guided execution.
How to Import Workouts into Garmin Connect
Garmin Connect allows importing workouts via JSON files. After downloading your workout file:
- Open Garmin Connect on the web (connect.garmin.com)
- Go to Training → Workouts
- Click Import Workout and select your downloaded .json file
- The workout appears in your library and syncs to your watch on next connection
- On your watch: Training → Workouts → My Workouts
Types of Running Intervals
Jack Daniels categorises running intervals by intensity relative to VO₂max:
- Interval (I-pace): ~95–100% VO₂max. Classic 1000m–1200m reps. Develops VO₂max directly.
- Threshold (T-pace): ~84–88% VO₂max. Tempo runs of 20–40 min or cruise intervals. Raises lactate threshold.
- Repetition (R-pace): ~105%+ VO₂max. Short 200–400m reps with full recovery. Develops speed and economy.