Leg Speed Builder
Workout - Leg Speed Builder
- 15min @ 6'00''/km
- 12 lots of:
- 400m @ 5'00''/km
- 1min rest
- 10min @ 7'00''/km
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A quick rundown of Lee Grantham’s Unleash Your Potential: How Interval Training Can Shatter Your Personal Bests. Worth watching. We’ve summarized the essentials so you can run this workout right away. Watch the full video for the complete picture.
Key points
- Interval training is the fastest path to faster PRs across all distances (5K through ultra-marathon) by adding speed work and shifting your mental approach.
- Watch out for “gray-zone” easy runs that drift faster than they should. Pull them back to true recovery so you can bring real effort to quality sessions.
- Short, fast 400 m repeats build leg speed, which makes longer stretches and goal-race pace feel more attainable.
- Build the number of reps gradually, holding your 400 m split around 70 seconds (about 1:10 for 800 m) with 60 seconds between efforts.
Workout example
Warm-up: 10-15 minutes easy running plus dynamic stretches
Main set: 20 x 400 m at about 70 s each (or 1:10 per 800 m) with 60 s recovery.
Build-up: start with 10-12 reps at target pace, then add 2-3 reps weekly until reaching 20.
Cool-down: 10 minutes easy running.Practical tips
- Hold easy runs at true recovery speed to avoid the “gray-zone” trap.
- Treat speed work as a habit. Keep at it even when races get postponed.
- Watch how your body responds. Heart rate will climb, but effort should feel controlled.
- Use the Pacing app to dial in your 400 m pace based on current fitness.
Closing note Run this session once this week, adjust the 400 m split in the Pacing app, and track your marathon pace gains.
References
- Unleash Your Potential: How Interval Training Can Shatter Your Personal Bests - YouTube (YouTube Video)