Whether you’re chasing a bus or aiming to beat a marathon personal best, speed matters. It’s a defining hallmark of physical ability that athletes, coaches, and physical therapists strive to improve. But what truly determines how fast you can move? A new study provides some fascinating insights into this, highlighting key muscles and mechanics at play at various speeds. Let’s break down what you need to know to improve your speed and running performance.
Key Takeaways
- Low Speeds: Your ankle plantar flexors play a significant role in energy absorption and production.
- Medium Speeds: You increase stride length as speed rises, eventually focusing on stride frequency once stride length peaks.
- High Speeds: Your hip extensors become the main drivers of energy, supporting faster stride frequency.
- Knee Flexors: Critical for energy absorption at high speeds, taking on increasing demands compared to other muscle groups.
The Science of Speed: How Muscles Drive Performance
A recent study took an in-depth look at running mechanics, joint motion, and muscle contributions across different speeds. By studying middle-distance runners at six distinct speeds, the researchers highlighted how our bodies adapt as we speed up.
Stride Mechanics: The Foundation of Speed
Your stride is composed of two key elements: stride length (distance covered from one step to the next) and stride frequency (number of strides per minute). At lower speeds, stride length largely determines your pace. As you accelerate to medium speeds, stride length extends until it stabilizes, at which point stride frequency takes over as the primary driver of speed. At high speeds, stride frequency becomes essential in propelling you forward.
Muscle Contributions at Different Speeds
- Slow to Moderate Speeds: At low speeds, the ankle plantar flexors provide more than 60% of the energy production and absorption during the stance phase. As speed increases to moderate levels, hip extensors begin to contribute significantly, assisting with stance and swing.
- High Speeds: At higher speeds, there’s a distinct shift. The hip extensors become key players, accounting for over 40% of speed generation. While the plantar flexors remain valuable, their proportional role diminishes as stride frequency demands rise. Meanwhile, the knee flexors take on more force absorption, especially during the late swing phase.
Practical Applications: Train Smarter, Run Faster
Understanding how different muscles contribute to speed allows you to focus on what matters most for your goals:
- Identify Key Muscles for Your Goal
- Distance Runners: Focus on strengthening the plantar flexors, knee flexors, and extensors, with added emphasis on hip stability.
- Speed Seekers: Prioritize hip extensors, hip flexors, and ankle plantar flexors, with attention to knee flexor strength.
- Load Management & Fatigue Monitoring
- Recognize that different speeds engage various muscles. To prevent overloading key muscles, structure your training around the demands of each pace. For example, avoid heavy hip and knee flexor fatigue before a high-speed session.
- If experiencing strain in a particular muscle, adjust the speed of your workouts to shift demands and promote recovery.
Real-Life Example: A Case Study in Marathon Performance
At ADAPT Recharge, we recently worked with a marathon runner preparing for her first race in over three years. After a detailed assessment, we identified specific muscle weaknesses that were impacting her stride efficiency, particularly at longer distances.
When reviewing her running gait, we noticed that as she hit the 20-mile mark, her stride length started to shorten, and her pace dropped significantly. Analysis showed her reliance on the ankle plantar flexors, which play a crucial role in energy production and absorption at slower speeds, was strong. However, as the miles increased, her hip extensors—a key muscle group for sustaining higher speeds over distance—showed signs of fatigue, causing her stride to shorten.
Further testing, including single-leg hops and squat assessments, highlighted a slight imbalance in her hip and knee flexors. We discovered her knee flexors were not absorbing impact as effectively as needed for marathon-length distances, leading to increased muscle strain as she tired.
Based on this analysis, we developed a targeted training plan focusing on hip extensor and knee flexor strength, combined with specific endurance drills to improve her efficiency in the latter half of the marathon. With this approach, we aimed to enhance her stride consistency and sustain her energy output across the full race distance.
Our client went on to complete her marathon with a personal best time, maintaining a steady pace through the finish line. Her newfound strength and efficiency helped her tackle the demanding final miles without losing form.
Want to run faster and reach your speed goals? Our experts at ADAPT Recharge are here to help! Click here for your free assessment and discover how we can optimize your performance today.
