SPM in Running: Understanding Cadence, Benefits, and How to Improve It

What is SPM in Running?

SPM, or Strides Per Minute, in running refers to your running cadence – the total number of steps your feet take per minute. It is a fundamental metric that offers insights into a runner's efficiency, form, and potential for injury prevention.

Understanding Strides Per Minute (SPM)

SPM, often used interchangeably with "cadence," quantifies the rate at which your feet contact the ground. It's a key component of running mechanics, alongside stride length. While stride length measures the distance covered with each step, SPM measures how frequently those steps occur. A higher SPM indicates a quicker turnover of the legs, while a lower SPM suggests longer, slower strides.

The Science Behind Running Cadence

Optimizing SPM is rooted in biomechanical principles. When you run, your body absorbs impact forces with each foot strike. The magnitude of these forces is influenced by various factors, including your cadence.

• Ground Contact Time: A higher SPM typically correlates with a shorter ground contact time. This means your foot spends less time on the ground, reducing the duration of impact and the braking forces that can slow you down.
• Vertical Oscillation: While not a direct measure of SPM, a higher cadence often encourages a more efficient running form with less vertical bounce. Excessive vertical oscillation wastes energy by moving the body up and down unnecessarily instead of forward.
• Overstriding: A common issue, overstriding occurs when a runner's foot lands too far in front of their center of mass, often with a straight knee. This creates a significant braking force and increases impact stress on joints. Increasing SPM naturally shortens stride length, making it more challenging to overstride and promoting a more midfoot or forefoot landing closer to the body.

Why Does SPM Matter?

Understanding and potentially adjusting your SPM can yield several significant benefits for runners:

• Injury Prevention:
  • Reduced Impact Forces: A higher cadence (shorter strides) generally reduces the peak impact forces on your joints (knees, hips, ankles, lower back). This lessens the cumulative stress over time, potentially lowering the risk of common running injuries like patellofemoral pain syndrome, IT band syndrome, and shin splints.
  • Improved Joint Loading: Shorter strides promote landing with a slightly more bent knee and directly under your center of mass, distributing forces more evenly across the joints.
• Enhanced Running Economy and Efficiency:
  • Less Braking: Overstriding creates a braking effect, requiring more energy to overcome this deceleration. A quicker turnover minimizes this braking, allowing more of your energy to propel you forward.
  • Optimized Energy Use: By reducing wasted vertical motion and braking, your body can utilize energy more effectively for forward propulsion, leading to better running economy (using less oxygen for a given pace).
• Improved Performance:
  • Faster Turnover: A higher SPM allows for a quicker response time and the ability to increase pace more rapidly.
  • Better Rhythm and Flow: A consistent, higher cadence can feel more rhythmic and effortless, particularly during longer runs.

Optimal SPM: Is There a Magic Number?

For many years, the "magic number" of 180 steps per minute was popularized by running coach Jack Daniels, based on observations of elite runners. While 180 SPM serves as a good general guideline, it's crucial to understand that there is no single "optimal" SPM for every runner, every pace, or every terrain.

Factors influencing your ideal SPM include:

• Pace: Your SPM naturally increases as your running pace increases. A sprint will have a much higher SPM than a leisurely jog.
• Height and Leg Length: Taller runners with longer legs may naturally have a slightly lower SPM than shorter runners for the same pace.
• Experience Level: Beginner runners often have a lower SPM (around 150-160), while experienced runners tend to have a higher cadence.
• Terrain: Running uphill might naturally decrease your stride length and increase SPM, while downhill might allow for longer strides and a slightly lower SPM. Trail running might involve more varied SPM than road running.
• Fatigue: As you become fatigued, your SPM may naturally drop, and your stride length may increase as you try to compensate.

Instead of rigidly aiming for 180 SPM, the goal should be to find a cadence that feels natural, efficient, and minimizes impact for your body and your specific running goals.

How to Measure Your SPM

Measuring your SPM is straightforward with modern technology:

• GPS Running Watches: Most modern GPS watches (e.g., Garmin, Apple Watch, Coros, Suunto) automatically track and display your real-time and average SPM during a run.
• Foot Pods: Devices like Stryd or other dedicated foot pods can provide highly accurate cadence data.
• Smartphone Apps: Many running apps utilize your phone's accelerometer to estimate cadence.
• Manual Count: For a quick estimate, count the number of times one foot strikes the ground in 30 seconds and multiply by 4. Or count total steps in 15 seconds and multiply by 4.

Strategies to Improve Your SPM

If your current SPM is significantly lower than typical recommendations (e.g., below 160 for easy runs) and you experience frequent injuries or feel inefficient, a gradual increase may be beneficial.

• Focus on Short, Quick Steps: Consciously think about taking lighter, quicker steps rather than longer, powerful ones. Imagine running on hot coals.
• Use a Metronome or Cadence App: Many running watches and smartphone apps have a metronome function. Set it to your desired SPM target and try to match your foot strikes to the beat. Start with a small increase (e.g., 5-10 steps per minute) from your current average.
• Incorporate Drills:
  • Quick Feet Drills: Rapidly tap your feet on the spot, focusing on quick ground contact and minimal lift.
  • High Knees/Butt Kicks: While primarily for warm-up and form, these drills emphasize quick leg turnover.
• Run to Music with a Specific BPM: Find songs with a beats per minute (BPM) that matches your target SPM.
• Gradual Increase: Do not try to drastically change your SPM overnight. Increase it by 3-5% for a few weeks, then re-evaluate. Your body needs time to adapt to the new movement pattern.
• Focus on Landing: Concentrate on landing lightly with your foot more directly underneath your body, rather than out in front. This naturally encourages a shorter stride and higher SPM.

Potential Pitfalls and Considerations

While increasing SPM can be beneficial, it's important to approach it thoughtfully:

• Forcing an Unnatural Cadence: Trying to hit a specific SPM that feels awkward or forced can lead to new injuries or a less efficient stride.
• Ignoring Other Factors: SPM is one piece of the running form puzzle. Strength, flexibility, mobility, and overall training load are equally vital.
• Context Matters: A higher SPM isn't always better. For example, during steep uphill climbs, a lower SPM with more powerful strides might be more efficient.
• Listen to Your Body: Pay attention to how changes feel. If increasing your SPM causes discomfort or pain, revert to what feels natural and consult a running coach or physical therapist.

Conclusion: Integrating SPM into Your Training

SPM is a powerful metric for understanding and refining your running form. By focusing on a slightly higher, more efficient cadence, many runners can reduce impact forces, improve running economy, and enhance overall performance. However, it's crucial to remember that individualized adaptation is key. Rather than chasing an arbitrary number, strive for a cadence that feels natural, minimizes stress on your body, and allows you to run efficiently and enjoyably. Integrate SPM awareness into your training as a tool for continuous improvement, always prioritizing comfort and injury prevention.