Running Performance Assessment – Strengths and Weaknesses
Understanding What Truly Limits Your Performance
In running, improving isn’t just about running more or following a generic training plan. At some point, every runner encounters specific physiological limits. Shortness of breath, burning legs, inability to accelerate, or loss of coordination – these sensations are not random.
Behind these signals lie clear physiological mechanisms. Contrary to what one might think, running performance mainly depends on three key limiting factors. These factors are universal: they affect both beginners and experienced athletes alike.
The goal of this tool is simple: make these factors visible, understandable, and actionable, without relying on complex laboratory tests. To achieve this, the three major physiological factors have been intentionally broken down into six axes, providing a more detailed and useful analysis to guide training.
The 3 Major Physiological Limiting Factors in Running
1. VO₂ max: Maximum Aerobic Capacity
VO₂ max represents the body’s maximum capacity to use oxygen during intense effort. It directly affects performance over short to medium distances and also the ability to sustain a high pace.
However, VO₂ max does not depend on a single organ. It relies on a complete chain:
breathing → heart → muscles.
That is why one runner may be limited by breathing, while another is constrained by cardiac load, even if their “theoretical” VO₂ max is similar.
In the tool, this factor is therefore split into two distinct axes.
1.a Breathing: Ventilatory Efficiency and Breath Control
This axis reflects the ability to breathe efficiently, coordinate breathing with exercise intensity, and ensure proper gas exchange.
When breathing is the limiting factor:
- breath becomes very fast and hard to control,
- a feeling of air hunger appears quickly,
- speaking becomes impossible,
- shortness of breath forces a slowdown before muscle fatigue sets in.
👉 Typical sensation: “I’m out of breath”
A low score on this axis indicates the limitation is primarily respiratory, not muscular or cardiac.
1.b Cardiac Endurance: Heart’s Ability to Sustain Effort
This axis concerns the cardiovascular system’s ability to maintain sufficient blood flow without excessive heart rate drift.
When the heart is the limiting factor:
- heart rate climbs very high, near maximum heart rate (HR max),
- the feeling of cardiac load dominates,
- general fatigue appears quickly,
- legs still feel relatively “okay.”
👉 Typical sensation: “My heart can’t take it anymore”
Here, performance is limited by cardiovascular load rather than breathing.
2. Lactate Threshold: Tolerance to Intensity
The lactate threshold represents the ability to maintain a high pace without excessive muscular and metabolic fatigue. In the tool, it logically combines two axes: muscular power and metabolic capacity.
2.a Muscular Power
This axis measures the muscles’ ability to generate force and accelerate, especially at the end of an effort.
When muscular power is limiting:
- inability to accelerate,
- loss of dynamism,
- sensation of “empty legs” (fatigued / weak legs).
2.b Metabolic Capacity
This axis evaluates the body’s ability to manage lactate accumulation and internal muscular fatigue.
When metabolic capacity is limiting:
- significant muscle burning,
- heavy and sore legs,
- difficulty maintaining pace despite relatively controlled breathing.
👉 Typical sensation: “My legs are burning”
3. Running Economy
The third limiting factor reflects the ability to produce efficient movement under fatigue. It is divided into two complementary axes: nervous system and running technique, the latter based on the COROS test, as self-assessment is challenging.
3.a Nervous System
This axis concerns neuromuscular recruitment and coordination under fatigue.
When the nervous system is limiting:
- loss of coordination and smoothness,
- drop in cadence,
- less precise movements,
- longer ground contact time.
3.b Running Technique
This axis reflects biomechanical efficiency, posture, movement economy, and the ability to accelerate. It is measured via the COROS test, since self-assessment is difficult.
When running technique is limiting:
- pelvis collapse,
- unstable posture,
- reduced mechanical efficiency,
- difficulty accelerating at the end of effort.
👉 Typical sensation: “I have no more legs”
Why 6 Axes Instead of Just 3?
The tool does not multiply criteria unnecessarily. It is based on a simple observation: the three main limiting factors are too broad to effectively guide training.
By splitting them into six axes:
- VO₂ max → breathing + cardiac endurance
- Lactate threshold → muscular power + metabolic capacity
- Muscular endurance → nervous system + running technique
it provides a precise mapping of strengths and weaknesses.
Training Recommendations for Each Axis
Based on your radar results, you can prioritize specific axes. Here are examples of exercises to effectively improve each of the six axes:
Breathing: To improve breathing and aerobic capacity, focus on sessions aimed at increasing VO₂ max, such as long intervals like 4x4 Norwegian repeats. Maintain a high but controlled intensity and focus on a steady breathing rhythm.
Cardiac Endurance: Strengthen your heart by regularly performing long runs in heart rate zones 1 and 2 out of 5, building a solid aerobic base. This enhances recovery and the ability to sustain faster paces.
Muscular Power: To boost strength and reactivity, combine targeted strength training with plyometric exercises (jumps, bounds, explosive squats). This also improves sprint power and running efficiency.
Metabolic Capacity: Work at high intensities through specific sessions like fartlek or prolonged efforts to better manage lactate accumulation and extend intensity tolerance.
Nervous System: Enhance coordination and smoothness by including technical drills, proprioception exercises, and activities targeting balance and precise movement.
Running Technique: To optimize running economy, rely on your COROS data analysis and complement it with stride drills, efficiency exercises, and posture corrections.
These recommendations allow you to target weaknesses precisely and progress in a coherent, structured way.
Purpose of the Self-Assessment Tool
This tool is neither a medical test nor a strict scientific measurement. It is a self-assessment tool based on runner sensations and real experience, typically during a 5 km effort.
Its purpose is to:
- highlight the dominant physiological limiting factors,
- visualize imbalances via a radar chart,
- guide training in a more targeted and effective way.
In short, the tool transforms often vague sensations into clear indicators, directly actionable to improve running performance.
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