Lee Grantham's 20x400m Speed Session

Workout - Lee Grantham's 20x400m Speed Session

• 10min @ 6'00''/km
• 20 lots of:
  • 400m @ 4'30''/km
  • 15s rest
• 5min @ 6'00''/km

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Intro

Lee Grantham walks through his strategy for running a sub-2:21 marathon. Here’s what we’ve pulled out so you can use this workout right away. Watch the full video for more context.

Key points

• Recovery runs (40 min) work best on an empty stomach in zone 1, ending with 3-5 min of easy walking. You should finish feeling better than when you started.
• Strength work (Monday) targets glutes, hamstrings, quads, and lower-leg power alongside core. Done twice weekly.
• Easy runs (Tuesday and Saturday) are 50 min at zone 1, finishing with 10 x 80 m pickups at goal marathon pace.
• Cycling: three 50 km sessions a week (around 1 h 40 min each) build aerobic fitness while giving your legs a break.
• Mid-week repeats (Wednesday): 20 x 400 m at 65-70 s per rep, after a 2 km easy warm-up and before a 1.5 km cool-down (about 12 km total). Each 400 m runs roughly 10% faster than marathon pace.
• Rest day (Thursday): no running or cycling. Eat, drink plenty of water, hold electrolytes, and a brief core workout.
• Long run (Sunday): 25 km, run as 5 km at 4 min/km (20% slower than marathon goal), 15 km at marathon pace (around 3:20/km), then 5 km back at 4 min/km. Add a 2 km warm-up and cool-down as needed.
• Nutrition: race morning is 5 bananas blended with water. During intense sessions, a gel every 20 min (roughly 80 g carbs/hr). After running, get 100 g carbs in within 10-15 min (try a banana-oat-milk smoothie).
• Recovery basics: sleep is the foundation. Manage stress, stay hydrated, keep electrolytes up.

Workout example (mid-week interval)

Warm-up: 2.5 km easy
Main set: 20 x 400 m at 65-70 s each (about 10% faster than marathon pace)
   - Keep effort consistent, treat each rep like a race
   - Recover briefly (15-20 s) between reps
Cool-down: 1.5 km jog to walk
Total: about 12 km

Adjust the 400 m pace based on your marathon goal. If your target is 3:20/km, aim for around 2:50/km on the repeats.

Closing note

Try this plan and use the Pacing app to dial in the paces for your current fitness. Adjust distances and intervals as you see fit. Stick with the fundamentals: easy recovery running, strength training, targeted speed work, and proper fueling.

References

• Training Week Breakdown for Sub-2:21 Marathon - YouTube (YouTube Video)