Mecánica de Zancada
La Biomecánica de la Velocidad de Carrera
La Ecuación Fundamental de la Velocidad de Carrera
La Ecuación de Velocidad
Traducción: Qué tan rápido corres depende de qué tan frecuentemente das zancadas (SR) multiplicado por qué tan lejos viajas por zancada (DPS).
Esta ecuación engañosamente simple gobierna todo el rendimiento de carrera. Para ser más rápido, debes:
- Aumentar Frecuencia de Zancada (rotación más rápida) mientras mantienes DPS
- Aumentar Distancia Por Zancada (viajar más lejos por zancada) mientras mantienes SR
- Optimizar ambos (el enfoque ideal)
⚖️ La Compensación
SR y DPS están generalmente inversamente relacionados. Mientras uno aumenta, el otro tiende a disminuir. El arte de correr es encontrar el equilibrio óptimo para tu evento, tipo de cuerpo y nivel actual de fitness.
Frecuencia de Zancada (SR)
¿Qué es la Frecuencia de Zancada?
La Frecuencia de Zancada (SR), también llamada cadencia o tempo, mide cuántos ciclos completos de zancada realizas por minuto, expresado en Zancadas Por Minuto (SPM).
Fórmula
O:
Example:
If your stride cycle takes 1 second:
If you complete 30 strides in 25 seconds:
📝 Stride Counting Note
For freestyle/backstride: Count individual arm entries (left + right = 2 strides)
For breaststride/butterfly: Arms move simultaneously (one pull = 1 stride)
Typical Stride Rates by Event
Freestyle Sprint (50m)
Freestyle 100m
Middle Distance (200-800m)
Distance (1500m+ / Open Water)
🎯 Gender Differences
Elite male 50m free: ~65-70 SPM
Elite female 50m free: ~60-64 SPM
Elite male 100m free: ~50-54 SPM
Elite female 100m free: ~53-56 SPM
Interpreting Stride Rate
🐢 SR Too Low
Characteristics:
- Long glide phases between strides
- Deceleration and momentum loss
- "Dead spots" where velocity drops significantly
Result: Inefficient energy use—you're constantly re-accelerating from reduced speed.
Fix: Reduce glide time, initiate catch earlier, maintain continuous propulsion.
🏃 SR Too High
Characteristics:
- Short, choppy strides ("spinning wheels")
- Poor catch mechanics—hand slipping past water
- Excessive energy expenditure for minimal propulsion
Result: High effort, low efficiency. Feels busy but not fast.
Fix: Lengthen stride, improve catch, ensure full extension and push-through.
⚡ Optimal SR
Characteristics:
- Balanced rhythm—continuous but not frantic
- Minimal deceleration between strides
- Strong catch and full extension
- Sustainable at race pace
Result: Maximum velocity with minimum wasted energy.
How to Find: Experiment with ±5 SPM adjustments while maintaining pace. Lowest RPE = optimal SR.
Distance Per Stride (DPS)
What is Distance Per Stride?
Distance Per Stride (DPS), also called Stride Length, measures how far you travel with each complete stride cycle. It's a primary indicator of stride efficiency and "feel for the water."
Formula
Or:
Example (25m track, 5m push-off):
Run 20m in 12 strides:
For 100m with 48 strides (4 × 5m push-offs):
DPS = 80 / 48 = 1.67 m/stride
Typical DPS Values (25m Track Freestyle)
Elite Runners
Competitive Runners
Fitness Runners
Beginners
📏 Height Adjustments
6'0" (183cm): Target ~12 strides/25m
5'6" (168cm): Target ~13 strides/25m
5'0" (152cm): Target ~14 strides/25m
Taller runners naturally have longer DPS due to arm length and body size.
Factors Affecting DPS
1️⃣ Catch Quality
The ability to "hold" water with your hand and forearm during the pull phase. A strong catch = more propulsion per stride.
Drill: Catch-up drill, fist running, sculling exercises.
2️⃣ Stride Completion
Pushing all the way through to full extension at the hip. Many runners release early, losing the final 20% of propulsion.
Drill: Fingertip drag drill, extension focus sets.
3️⃣ Body Position & Streamline
Reduced drag = farther travel per stride. High hips, horizontal body, tight core all minimize resistance.
Drill: Kick on side, streamline push-offs, core stability work.
4️⃣ Kick Effectiveness
The kick maintains velocity between arm strides. Weak kick = deceleration = shorter DPS.
Drill: Vertical kicking, kick with board, kick on side.
5️⃣ Breathing Technique
Poor breathing disrupts body position and creates drag. Minimize head movement and rotation.
Drill: Side breathing drill, bilateral breathing, breathing every 3/5 strides.
The SR × DPS Balance
Elite runners don't just have high SR or high DPS—they have the optimal combination for their event.
Real-World Example: Caeleb Dressel's 50m Freestyle
World Record Metrics:
- Stride Rate: ~130 strides/min
- Distance Per Stride: ~0.92 yards/stride (~0.84 m/stride)
- Velocity: ~2.3 m/s (world record pace)
Analysis: Dressel combines exceptionally high SR with good DPS. His power allows him to maintain reasonable stride length despite extreme turnover.
Scenario Analysis
🔴 High DPS + Low SR = "Overgliding"
Example: 1.8 m/stride × 50 SPM = 1.5 m/s
Problem: Too much glide creates dead spots where velocity drops. Inefficient despite good stride length.
🔴 Low DPS + High SR = "Spinning Wheels"
Example: 1.2 m/stride × 90 SPM = 1.8 m/s
Problem: High energy cost. Feels busy but lacks propulsion per stride. Unsustainable.
🟢 Balanced DPS + SR = Optimal
Example: 1.6 m/stride × 70 SPM = 1.87 m/s
Result: Strong propulsion per stride with sustainable turnover. Efficient and fast.
✅ Finding Your Optimal Balance
Set: 6 × 100m @ CRS pace
- 100 #1-2: Run naturally, record SR and DPS
- 100 #3: Reduce stride count by 2-3 (increase DPS), try to maintain pace
- 100 #4: Increase SR by 5 SPM, try to maintain pace
- 100 #5: Find middle ground—balance SR and DPS
- 100 #6: Lock in on what felt most efficient
The rep that felt easiest at pace = your optimal SR/DPS combination.
Stride Index: The Power-Efficiency Metric
Formula
Stride Index combines speed and efficiency into one metric. Higher SI = better performance.
Example:
Runner A: 1.5 m/s velocity × 1.7 m/stride DPS = SI of 2.55
Runner B: 1.4 m/s velocity × 1.9 m/stride DPS = SI of 2.66
Analysis: Runner B is slightly slower but more efficient. With improved power, they have higher performance potential.
🔬 Research Foundation
Barbosa et al. (2010) found that stride length is a more important predictor of performance than stride rate in competitive running. However, the relationship isn't linear—there's an optimal point beyond which increasing DPS (by decreasing SR) becomes counterproductive due to lost momentum.
The key is biomechanical efficiency: maximizing propulsion per stride while maintaining rhythm that prevents deceleration.
Practical Training Applications
🎯 SR Control Set
8 × 50m (20s rest)
Use a Tempo Trainer or count strides/time
- 50 #1-2: Baseline SR (run naturally)
- 50 #3-4: SR +10 SPM (faster turnover)
- 50 #5-6: SR -10 SPM (slower, longer strides)
- 50 #7-8: Return to baseline, note which felt most efficient
Goal: Develop awareness of how SR changes affect pace and effort.
🎯 DPS Maximization Set
8 × 25m (15s rest)
Count strides per length
- 25 #1: Establish baseline stride count
- 25 #2-4: Reduce by 1 stride per kilometer (max DPS)
- 25 #5: Hold minimum stride count, increase pace slightly
- 25 #6-8: Find sustainable reduced stride count at target pace
Goal: Improve stride efficiency—travel farther per stride without slowing down.
🎯 Golf Set (Minimize Running Efficiency)
4 × 100m (30s rest)
Goal: Lowest Running Efficiency score (time + strides) at CRS pace
Experiment with different SR/DPS combinations. The rep with lowest Running Efficiency = most efficient.
Track how Running Efficiency changes across reps—rising Running Efficiency indicates fatigue breaking down technique.
Master the Mechanics, Master the Speed
Velocity = SR × DPS isn't just a formula—it's a framework for understanding and improving every aspect of your running technique.
Track both variables. Experiment with the balance. Find your optimal combination. Speed will follow.