Calculating Trail Running Training Volume: Equivalent Conversion of Vertical Ascent Meters (VAM)

Introduction

“I ran 15 kilometers today.” — This statement carries almost no meaning in the context of trail running, because the same 15 kilometers imposes vastly different loads on the body depending on whether it’s a flat forest trail or a ridge workout with 1,200 meters of continuous climbing. Trail runners need a more precise tool for quantifying training, and Vertical Ascent Meters (VAM) is exactly that tool.

What is VAM (Vertical Ascent Meters)

VAM (or D+, from the French “dénivelé positif”) refers to the cumulative positive elevation gain during a single training session or race (the total of all uphill sections; descents are not counted). It is one of the most important training load metrics in trail running and mountaineering.

Why VAM is more accurate than distance:

As the table shows, distance cannot reflect true load, while VAM can more accurately predict finish time and energy expenditure.

VAM Equivalent Conversion Rules for Trail Running

The conversion of trail running training volume typically uses the following rule of thumb (applicable to moderate-grade mountain trails):

Vert Ratio (climbing conversion):

• 100 meters of vertical ascent ≈ 1 kilometer of flat running (in terms of energy expenditure)
• Some systems use 150 meters of ascent = 1 kilometer (if the grade is steeper or the terrain is rougher)

Practical conversion examples:

• Dakeng Trail 10 (4.5 km + 650m ascent):
  • Equivalent distance = 4.5 + (650 ÷ 100) = 4.5 + 6.5 = 11 equivalent kilometers
• Qixing Mountain loop (12 km + 520m ascent):
  • Equivalent distance = 12 + (520 ÷ 100) = 12 + 5.2 = 17.2 equivalent kilometers

Weekly VAM Recommendations for Training Volume

Progressive principle: Weekly VAM increases should not exceed 10–15% of the previous week, following the “10% rule” to avoid overtraining.

Using VAM to Monitor Training Periodization

Trail running training cycles can be structured around VAM targets:

Base phase (12–16 weeks out):

• Focus on aerobic foundation, with VAM set at 60–70% of the target race’s demands
• Emphasize technical training (uphill/downhill technique, terrain reading)
• 1–2 long, low-intensity trail sessions per week

Build phase (8–12 weeks out):

• Increase VAM to 80–90% of the target
• Incorporate hill repeat workouts
• Begin practicing the nutrition and hydration strategy for the target race

Peak phase (4–8 weeks out):

• Accumulate the highest VAM week, approaching or even exceeding the target race’s VAM
• At least one full “simulation race” to rehearse gear and nutrition

Taper phase (2–3 weeks before the race):

• Reduce VAM to 50–60% of normal
• Maintain training frequency while significantly reducing training volume

VAM Recording in Common Tools

How to view weekly VAM on Strava: Home → Training → Training Log, where you can view cumulative ascent per week.

Practical Recommendations

1. Set weekly VAM goals: Instead of setting a “50 km weekly run” goal, set a “1,500 meters weekly VAM” goal
2. Track VAM history: Monitoring long-term weekly VAM trends is an objective indicator of training progress
3. Compare race demands: Before registering for a race, check the race’s D+ (elevation gain) to assess whether your training volume is sufficient
4. Grade correction: Enable “Grade Adjusted Pace” in your training app for a more accurate assessment of effort

Conclusion

VAM gives trail runners a measuring stick truly suited to mountain terrain. When you start thinking in terms of elevation gain rather than kilometers, your plan becomes more precise and your progress becomes more traceable. The next time you draw up a training plan, ask yourself first: “What’s my vertical ascent goal this week?”

Related Reading

• Planning Weekly Training Volume for Vertical Ascent (D+) in Trail Running Training
• Trail Running Vertical Ascent Training: Periodizing Vert into Your Legs
• Cycling Aerodynamics: The Scientific Analysis of VAM and Climbing Efficiency
• Trail Training Logs and Ascent D+: Don’t Just Look at Distance