Glossary
Interval Training
Updated February 28, 2026
Interval training alternates focused work and recovery blocks to build fitness efficiently without turning every session into a grind.
Intent first
| Intent | Rep or duration style | Primary marker |
|---|
| Aerobic capacity | Repeats with short intervals and full recoveries | Better pace at upper steady zones |
| Lactate tolerance | Mid-length intervals with incomplete recovery | Higher tolerance for sustained discomfort |
| Speed and neuromuscular quality | Brief sprint bouts with long recovery | Better coordination and stride output |
Progression blocks
| Level | Weeks | Base shape | Weekly target |
|---|
| Beginner | 1 to 4 | 4 to 6 reps in one interval family | 1 interval session per week |
| Intermediate | 5 to 8 | Two formats per week, one low density, one high density | 2 interval sessions per week |
| Advanced hold | 9 to 12 | Mixed ladders, controlled session density | 2 to 3 interval sessions with full reload |
Overreach signals linked to recovery
| Signal | Data source | Action |
|---|
| Elevated resting HR for 3 consecutive mornings | heart rate zones trend drift | Reduce interval count by 20 to 30 percent |
| Poor sleep and low motivation | recovery time pattern | Replace with aerobic easy work for 48 to 72 hours |
| Persistent soreness in repeated load windows | session logs and subjective fatigue | Cut one high-intensity block and reset load |
| Performance plateaus with high effort feel | training diary and RPE trend | Maintain interval count but enlarge recovery windows |