1. Why Run Doubles?
Two-a-day training (doubles) is a staple of elite distance running. For serious recreational runners, it can be a powerful tool for increasing volume without the fatigue of longer single runs.
Benefits of Doubles Training
- Higher volume: Run more miles without single runs becoming too long
- Better recovery: Two shorter runs are less taxing than one long run
- Metabolic benefits: More frequent stimulus for aerobic adaptations
- Time efficiency: Fit more training into a busy schedule
- Mental freshness: Shorter runs can feel easier than grinding long ones
The Science Behind Doubles
Research suggests that splitting volume into two sessions can provide unique benefits:
Physiological Benefits
- Twice-daily metabolic activation
- Lower muscle glycogen depletion per run
- Reduced cumulative fatigue
- More time at aerobic intensities
Practical Benefits
- Easier to schedule shorter runs
- Less muscle damage per session
- Quicker recovery between runs
- More flexibility in training
When Doubles Make Sense
| Scenario | Consider Doubles? |
|---|---|
| Running 60+ miles/week, single runs getting too long | Yes - ideal use case |
| Morning and evening availability, limited lunch time | Yes - practical fit |
| Running 30 miles/week, want to increase | Maybe - try adding days first |
| Injury-prone when runs exceed 10 miles | Yes - reduce per-run stress |
| New to running (less than 2 years) | No - build base first |
2. Prerequisites for Doubles
Doubles are an advanced training method. Jumping in too soon leads to overtraining, injury, and burnout. Ensure you meet these criteria first.
Minimum Requirements
- Experience: 2+ years of consistent running
- Volume: Currently running 50+ miles/week comfortably
- Frequency: Already running 6-7 days/week
- Health: Injury-free for 3+ months
- Recovery: Good sleep habits (7+ hours nightly)
- Time: Can commit to structured eating/recovery
Signs You're Ready
Green Lights
- Easy runs feel truly easy
- Recovery between hard sessions is quick
- No persistent fatigue or soreness
- Current mileage feels sustainable
- Excited about adding volume
Red Flags - Not Ready
- Frequently tired or burned out
- Nagging injuries or pain
- Poor sleep quality
- Struggling with current volume
- Haven't maximized single-run training
Alternative Approaches First
Before adding doubles, ensure you've optimized these:
- Run more days: Move from 5 to 6 or 6 to 7 days/week first
- Extend runs gradually: Can you handle 90+ minute long runs?
- Improve quality: Are your workouts well-executed?
- Optimize recovery: Sleep, nutrition, stress management
- Cross-training: Have you tried supplemental activities?
3. Structuring Your Doubles
Not all doubles are created equal. The key is pairing sessions that complement rather than compete with each other.
The Primary/Secondary Model
Most effective doubles have one main run and one supplementary run:
- Primary run: Your main workout - longer, harder, or your key session
- Secondary run: Shorter, easier, pure recovery/base building
- Typical split: 60-70% primary, 30-40% secondary
Timing Between Sessions
| Gap | Status | Notes |
|---|---|---|
| 8+ hours | Ideal | Good glycogen recovery, muscle repair begins |
| 6-8 hours | Good | Partial recovery, works well for most |
| 4-6 hours | Adequate | Minimal recovery, second run may feel harder |
| Under 4 hours | Too short | Essentially one long run with a break |
Common Scheduling Patterns
AM/PM Split (Most Common)
Example: 6:00 AM primary run, 5:30 PM secondary run. 11+ hours between. Works well for 9-5 schedules.
Morning/Lunch Split
Example: 6:00 AM primary run, 12:00 PM secondary run. 6 hours between. Evenings free for recovery.
Lunch/Evening Split
Example: 12:00 PM primary run, 7:00 PM secondary run. 7 hours between. Good for night owls.
4. Workout Combinations
The key to successful doubles is smart pairing. Some combinations enhance training; others lead to overtraining.
Recommended Combinations
- Long run + easy shakeout: 14 miles AM, 4 miles easy PM
- Tempo + easy recovery: Tempo workout AM, 3-4 miles easy PM
- Easy + easy: Two moderate easy runs on recovery days
- Intervals + easy jog: Hard track session AM, easy 3 miles PM
- Easy + strides: Easy run AM, short run with strides PM
Combinations to Avoid
- Two hard workouts: Intervals AM and tempo PM = overtraining
- Long run + quality: 16 miles AM, tempo PM = injury risk
- Two long runs: 12 miles AM, 10 miles PM = excessive fatigue
- Hard run + hills: Threshold AM, hill repeats PM = too much
Sample Double Formats
| Day Type | AM Session | PM Session |
|---|---|---|
| Easy Day | 6-8 miles easy | 3-4 miles easy |
| Workout Day | Tempo/intervals (8-10 miles total) | 3-4 miles recovery |
| Long Run Day | 14-18 mile long run | 3-4 miles easy shakeout |
| Pre-Workout Day | 5-6 miles easy | 3 miles + strides |
5. Recovery Between Sessions
Recovery is everything with doubles. The window between runs is when you rebuild and prepare for the next session. Maximize it.
Immediate Post-Run (0-30 min)
- Refuel: Carbs + protein within 30 minutes
- Rehydrate: Replace fluids lost during run
- Cool down: Light stretching or foam rolling
- Compress: Compression gear if available
Between Sessions
Do
- Stay on your feet (gentle movement)
- Continue hydrating
- Eat regular meals/snacks
- Take a 20-30 min nap if possible
- Light stretching
Avoid
- Sitting for extended periods
- Heavy manual labor
- Skipping meals
- Dehydration
- Intense mental stress
Sleep Priority
With doubles, sleep becomes non-negotiable:
- Minimum: 7-8 hours per night
- Ideal: 8-9 hours per night
- Naps: 20-30 minutes between sessions can help
- Consistency: Same bedtime/wake time daily
- Quality: Dark room, cool temperature, no screens before bed
6. Nutrition for Doubles
Fueling becomes critical when running twice daily. You're burning more calories and depleting glycogen faster, requiring strategic nutrition.
Caloric Needs
Doubles can add 500-1000+ calories to daily needs:
- Each additional mile burns ~100 calories
- Under-eating leads to fatigue and poor recovery
- Track weight weekly - if dropping, eat more
- Better to eat slightly too much than too little
Daily Nutrition Timing
Pre-First Run
Light carbs 30-60 minutes before. Toast, banana, or energy bar. Coffee if desired. Avoid fat and fiber that slow digestion.
Post-First Run (Critical)
Within 30 minutes: 3:1 or 4:1 carb-to-protein ratio. Chocolate milk, recovery shake, or real food. 300-500 calories minimum.
Between Runs
Regular meals every 3-4 hours. Focus on carbohydrates for glycogen. Moderate protein. Stay hydrated.
Pre-Second Run
Light snack 30-60 minutes before if 4+ hours since last meal. Similar to pre-first-run: easy-to-digest carbs.
Post-Second Run/Dinner
Full meal with carbs, protein, and healthy fats. Replenish for overnight recovery. Don't skimp on calories.
Hydration Strategy
- Start hydrated: Drink 16-20 oz upon waking
- During runs: Drink when thirsty, more in heat
- Between sessions: Sip consistently, monitor urine color
- Electrolytes: Consider adding if sweating heavily
- Goal: Pale yellow urine throughout the day
7. Sample Training Weeks
Here are sample weeks showing how to incorporate doubles at different volume levels.
70 Miles/Week with 3 Doubles
85 Miles/Week with 4-5 Doubles
8. Troubleshooting
Common issues when starting doubles and how to address them.
Problem: Second run feels terrible
Causes: Insufficient recovery time, inadequate fueling, first run too hard
Solutions: Increase gap between runs, eat more between sessions, make first run easier, run second run slower
Problem: Constantly fatigued
Causes: Too much volume too soon, inadequate sleep, under-eating
Solutions: Reduce doubles frequency, prioritize 8+ hours sleep, increase calories, take a down week
Problem: Can't hit workout paces
Causes: Accumulated fatigue, doing too many doubles, workouts too close together
Solutions: Schedule doubles around easy days, ensure day before workout is light, reduce overall volume temporarily
Problem: Injury or persistent soreness
Causes: Overuse, insufficient recovery, ramped up too quickly
Solutions: Stop immediately, return to singles, see a physio if needed, rebuild gradually
9. Frequently Asked Questions
How quickly can I add doubles to my training?
Start with one double per week for 2-3 weeks. If that feels sustainable, add a second double. Maximum addition is one new double every 2-3 weeks. Most runners plateau at 3-5 doubles per week.
Should I run doubles year-round?
Not necessarily. Many runners use doubles during peak training and reduce to singles during base building or off-season. Periodizing doubles can prevent burnout and allow your body to recover from high-volume blocks.
Can I replace a double with cross-training?
Yes. A common approach is AM run + PM bike or swim. This reduces running impact while maintaining cardio stimulus. Just ensure the cross-training is truly easy if paired with a hard run.
What's the minimum useful second run?
About 20-25 minutes or 3 miles. Shorter than this provides minimal training benefit. The purpose is aerobic stimulus and recovery, not just logging miles. If you only have 15 minutes, skip it.
Do elite runners really run twice every day?
Many do, but not all. Elite marathoners commonly run 10-14 times per week, which means most days are doubles. However, even pros have single-run days and complete rest days. Quality still matters more than quantity.
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