When should beginners start doing speed work?
Beginners should wait 6-12 months after starting running before adding structured speed work like intervals or tempo runs. Build an aerobic base of 30+ km per week first. Strides (4-6 x 20 seconds at fast pace) can be added after 8-12 weeks as a gentle introduction to faster running.
The answer most coaches won't give you: not yet, no matter when you're asking. Structured speed work — 800m repeats, tempo runs, VO2max intervals — damages untrained connective tissue and hormones in ways that easy running doesn't. You need a base of 30-40 km per week for at least 8-12 weeks before your tendons can handle threshold pace, and 6-12 months of consistent running before you should be doing maximal intervals. That said, you can introduce 'speed' carefully in earlier phases. After 8 weeks of run-walk, add 4-6 strides at the end of one run per week: 20 seconds of relaxed fast running, 60 seconds walking, repeat. This teaches your nervous system and biomechanics without creating fatigue. After 3-4 months, you can add light fartlek (unstructured pace changes during an easy run). True intervals and tempo work should wait until you can run 40 km per week comfortably with no aches. Speed work skipped for 6 months won't hurt your fitness — you'll gain 90% of possible improvements from easy running plus strides alone in year one. Speed work added too early will put you in a boot or ruin your tendons for a season.