Flexibility for Athletes: What Actually Determines How Flexible You Are

If you've ever wondered why some people seem to move effortlessly through deep ranges of motion while others feel like they're fighting their own body just to touch their toes — this post is for you.

This is Part 2 of the Snow Beast Performance Stretching 101 series. Part 1 covered the different types of stretching and when to use them. Here, we go deeper into the factors that actually determine your flexibility, what the research says about how much you can change it, and the full list of benefits stretching offers beyond just range of motion. Part 3 of this series takes things further — exploring eccentric strengthening as one of the most effective tools for improving flexibility and muscular function simultaneously.

Here's what most people don't realize: flexibility isn't purely a matter of effort or consistency. It's shaped by factors you control, factors you partially control, and factors you can't change at all. Understanding the difference is one of the most clarifying things an athlete can do — because it shifts the goal from chasing someone else's range of motion to optimizing your own.

The Factors That Determine Your Flexibility

Genetics

Genetics account for approximately 60–70% of an individual's flexibility. That's a significant portion — and it means that two athletes following identical stretching programs will often end up at very different places in terms of range of motion. This isn't a failure of effort or consistency. It's biology.

For athletes who come from naturally flexible family lines, this works in their favor. For those whose parents struggled to reach their knees, it sets a realistic ceiling for what's achievable regardless of how diligently they stretch. As the science around epigenetics — the study of how behavior and environment influence genetic expression — continues to develop, there may be more nuance to this picture. For now, the practical takeaway is straightforward: genetics set the parameters, and effort determines how close you get to your individual ceiling.

Bony Anatomy

Like genetics, bony anatomy is predetermined and essentially unmodifiable. The shape of your joints — particularly the depth and orientation of the hip socket, the shape of the femoral head, and the structure of the spine — directly influences your available range of motion at those joints.

A practical example: many males, particularly those of Eastern European descent, have relatively deep hip sockets. This anatomy is excellent for joint stability but creates a structural ceiling for hip flexion and rotation. For these athletes, the end of their available range doesn't feel like a muscle stretch — it feels like a block. Because it is. The bone is the limiting factor, not the soft tissue.

In cases like this, the most effective strategy isn't to push harder into the restriction — it's to optimize the flexibility and strength of the muscles around the joint and find movement patterns that work with that anatomy rather than against it. A physical therapist familiar with structural assessment can help identify when a limitation is bony versus soft tissue, which dramatically changes the appropriate intervention.

Activity Level and Exercise

This is the factor that matters most in practical terms — because it's the only one that's fully within your control. The challenge is that activity level and exercise account for only about 10% of total flexibility. That might feel discouraging, but it reframes the goal usefully: stretching and mobility work won't transform your body into something your genetics and anatomy don't support, but they will move you meaningfully toward your individual potential — and that potential is worth pursuing.

Consistent stretching, mobility work, and strength training through full ranges of motion all contribute to flexibility improvements over time. The athletes who move best aren't necessarily the ones who were born most flexible — they're the ones who have worked consistently within their parameters and built the best possible version of what their body allows.

What Happens to Flexibility as You Age

Research suggests that from approximately age 20 to 50, the average person loses around 10% of their flexibility per decade — a potential 30% decline over that window if nothing is done to maintain it. That decline affects the ability to touch your toes, reach overhead, rotate through the spine, and perform the full range of movements that athletic activity and daily life demand.

The good news is that this trajectory is not fixed. Consistent stretching and mobility work have been shown to significantly improve flexibility at any age and to slow or reverse age-related decline when maintained over time. The athletes who move well in their 50s and 60s are almost universally the ones who made flexibility and mobility part of their regular practice in their 30s and 40s — not the ones who waited until stiffness became a problem.

This is one of the reasons flexibility training is treated as a year-round priority at Snow Beast Performance — not just a warm-up afterthought or a response to injury. For active adults in Vermont spending significant time skiing, snowboarding, hiking, or trail running, maintaining flexibility and mobility through all seasons is one of the most reliable ways to stay healthy and performing well for the long term.

The Benefits of Stretching Beyond Flexibility

When most people think about stretching, they think about range of motion. But the benefits of a consistent stretching practice extend well beyond how far you can reach. Research supports stretching as a meaningful contributor to a broad range of health and performance outcomes:

Performance and physical capacity:

• Improved range of motion through multiple mechanisms

• Enhanced athletic and physical performance

• Improved posture and movement efficiency

• Better balance and stability

• Increased muscle strength and hypertrophy when combined with appropriate loading

Recovery and injury prevention:

• Reduced injury risk through improved tissue resilience and movement quality

• Decreased pain and inflammation

• Improved blood flow to working tissues

• Greater pain tolerance

Overall health and wellbeing:

• Increased parasympathetic nervous system activity — the body's rest and recovery state

• Reduced stress and anxiety

• Potential anti-inflammatory and immune system benefits with consistent long-term practice

For athletes, this list reframes stretching from a chore into a training variable with measurable returns across multiple dimensions of health and performance. It isn't just about touching your toes — it's about supporting the body's ability to perform, recover, and stay resilient across a full season and a full career.

What This Means for Your Training

Understanding your flexibility — where it comes from, what shapes it, and what you can realistically change — allows you to set better goals and make smarter decisions about your training.

If you've been frustrated by a lack of progress despite consistent stretching, it's worth considering whether the limitation is structural rather than soft tissue, whether your stretching technique and timing are optimized, or whether a different approach — like the eccentric strengthening covered in Part 3 of this series — might produce better results for your specific situation.

For a complete picture of how stretching fits into a broader mobility routine — including soft tissue work and stability training — our mobility exercises guide is a practical companion read.

If you're working through a specific flexibility limitation, dealing with pain that's restricting your range of motion, or simply want a program built around your individual anatomy and goals, our physical therapy services in Williston, VTstart with a thorough movement evaluation. Get started with a free 15-minute discovery call and let's figure out what's holding you back and what will actually move the needle.

FAQ: More on Flexibility for Athletes

Can adults significantly improve their flexibility, or is it too late after a certain age? It's never too late to meaningfully improve flexibility — research consistently shows that adults of all ages respond to consistent stretching and mobility work with measurable gains in range of motion. The rate of improvement may slow with age, and the ceiling set by genetics and anatomy doesn't change, but the distance between where you are and your individual potential is closeable at any age. Consistency over months and years produces results that short-term stretching programs rarely achieve.

Why do some people seem naturally flexible without ever stretching? Genetics account for approximately 60–70% of an individual's baseline flexibility, which means some people simply inherit a greater capacity for range of motion regardless of training. Naturally hypermobile individuals often have more elastic connective tissue — which can be an advantage in some contexts but comes with its own set of challenges, including reduced joint stability and a higher risk of certain injuries. Natural flexibility isn't always the advantage it appears to be without the strength and control to match it.

Is being more flexible always better for athletic performance? Not necessarily. Excessive flexibility without adequate strength and stability can actually impair performance and increase injury risk. The goal for most athletes isn't maximum flexibility — it's functional mobility: enough range of motion to perform the demands of their sport safely and efficiently, with the neuromuscular control to use that range effectively. This is why flexibility training is always most effective when paired with stability and strength work through the available range.

Why does my flexibility vary so much day to day? Daily variation in flexibility is normal and reflects changes in tissue hydration, nervous system state, sleep quality, training load, and stress levels. Tissues are generally more pliable when well-hydrated, rested, and warmed up — and more restricted when dehydrated, fatigued, or under high stress. This is one of the reasons that consistent daily practice — even brief sessions — tends to produce more stable flexibility gains than longer but less frequent sessions that are more vulnerable to daily variation.

Should I stretch differently for skiing and snowboarding versus other activities? Yes — the flexibility demands of skiing and snowboarding differ from those of running, cycling, or gym training. Hip flexion and extension, ankle dorsiflexion, thoracic rotation, and hip internal and external rotation are all particularly relevant for on-mountain performance. A stretching and mobility program tailored to skiing or snowboarding will prioritize these ranges specifically. Our ski physical therapy and snowboard physical therapy programs incorporate flexibility and mobility work specific to those demands.

Written by Alex Denny, DPT — Snow Beast Performance, Williston, VT