VAM in Running: Understanding, Calculation, and Performance Insights

What does VAM stand for in running?

VAM stands for Velocità Ascensionale Media, an Italian term translating to Average Ascent Speed or Mean Ascent Velocity. It is a metric primarily used in cycling and trail running to quantify a climber's vertical speed, indicating how quickly an individual gains elevation over time.

Understanding VAM: The Basics

VAM is a crucial performance indicator for athletes engaging in activities with significant elevation gain, such as mountain running, ultra-trail events, and uphill road races. Unlike horizontal speed (pace or velocity), which measures how fast you cover ground, VAM specifically measures your vertical movement against gravity. It provides a more accurate representation of effort and performance on ascents, as it normalizes for the steepness of the climb.

How VAM is Calculated

The calculation of VAM is straightforward, requiring two primary data points: total elevation gain and the time taken to achieve that gain.

• Formula: VAM = Total Elevation Gain (meters) / Time (hours)

• Units: VAM is typically expressed in meters per hour (m/h). For example, a VAM of 1000 m/h means an athlete gained 1000 meters of elevation in one hour.

• Example: If a runner ascends 500 meters in 30 minutes (0.5 hours), their VAM would be 500 m / 0.5 h = 1000 m/h.

It's important to note that VAM is an average over a given segment. An athlete's instantaneous VAM can fluctuate significantly throughout a climb depending on gradient changes, effort, and terrain.

Why VAM Matters for Runners

For runners, especially those tackling hilly or mountainous terrain, VAM offers unique insights:

• Objective Uphill Performance Metric: It provides a standardized way to compare climbing ability across different gradients and courses, something that raw pace cannot do. A runner might maintain a slow pace on a steep climb but still have a high VAM, indicating strong uphill performance.
• Reflects Power Output: Uphill running demands significant power output to overcome gravity. A higher VAM generally correlates with a higher power output relative to body weight, making it a good proxy for an athlete's physiological capacity on ascents.
• Pacing Strategy: Understanding your sustainable VAM can inform your pacing strategy for long climbs, helping you avoid burning out too early.
• Training Specificity: For athletes training for races with substantial vertical gain, VAM becomes a highly relevant training metric, allowing for focused development of uphill speed and endurance.

Interpreting Your VAM Score

What constitutes a "good" VAM score is highly contextual, depending on the runner's fitness level, body weight, the specific gradient of the climb, and the duration of the effort.

• Recreational Runners: Might sustain VAMs in the range of 400-700 m/h on moderate climbs.
• Experienced Trail Runners/Mountain Runners: Often achieve 800-1200 m/h on sustained efforts.
• Elite Climbers/Skyrunners: Can push VAMs well above 1500 m/h, and even over 2000 m/h for shorter, very steep segments.

Factors influencing VAM interpretation:

• Body Weight: Lighter runners generally have an advantage in VAM due to less mass to lift against gravity.
• Gradient: VAM tends to be highest on moderate to steep gradients (e.g., 8-15%). On very steep, technical terrain, movement speed might decrease, potentially lowering VAM, even if perceived effort is maximal.
• Duration: Sustaining a high VAM for short bursts is different from maintaining it over multi-hour ascents.

Practical Applications for Runners

Runners can leverage VAM in several ways to enhance their training and race performance:

• Training Tool for Hill Climbing: Use VAM to track improvements in your uphill fitness. By repeatedly running the same climb and monitoring your VAM, you can objectively assess progress.
• Pacing on Race Day: In races with significant climbing, knowing your sustainable VAM can help you set realistic goals for ascent times and conserve energy for later stages.
• Comparing Performance: VAM allows for a more equitable comparison of climbing performance with other runners, even if they tackled different climbs, provided the efforts were of similar duration and intensity.
• Analyzing Race Segments: Post-race analysis can pinpoint areas where VAM dropped significantly, indicating potential weaknesses or pacing errors.

Limitations and Considerations

While valuable, VAM is not without its limitations:

• Accuracy of Data: VAM relies on accurate elevation gain data, which can vary significantly between GPS devices and mapping software. Barometric altimeters generally provide more reliable elevation data than GPS-only devices.
• Not a Universal Metric: VAM is most relevant for sustained climbs. On flat or downhill sections, it's irrelevant, and on highly technical, uneven terrain, movement efficiency and technical skill might overshadow pure vertical speed.
• Influence of External Factors: Wind resistance, especially on exposed ridges, and extreme weather conditions can impact VAM without necessarily reflecting a change in physiological capacity.
• Weight Sensitivity: While an advantage for lighter runners, it also means VAM doesn't fully account for the absolute power output of heavier runners who might be generating more power but have a lower VAM due to their mass.

Beyond VAM: Complementary Metrics

For a holistic view of running performance, especially in varied terrain, consider VAM alongside other metrics:

• Running Power: Devices like Stryd provide real-time power output, offering a more direct measure of effort regardless of gradient or wind.
• Grade Adjusted Pace (GAP): This metric estimates what your pace would be on flat ground if you were expending the same effort as you are on current terrain (uphill or downhill).
• Vertical Ratio/Efficiency: Analyzing the ratio of vertical gain to horizontal distance covered can provide insights into climbing efficiency.

Conclusion: Harnessing VAM for Uphill Performance

VAM (Velocità Ascensionale Media) is a powerful, specialized metric for runners who frequently encounter significant elevation changes. By focusing on your vertical speed, VAM offers a clear, objective measure of your climbing ability, enabling more targeted training, smarter pacing, and a deeper understanding of your performance on the toughest parts of any course. While not the sole indicator of fitness, integrating VAM into your analytical toolkit can unlock new levels of performance in the world of uphill running.