By René Borg, Running Coach Ireland
www.runningcoach.ie | @running_coach_ireland
Why Stretching Alone Isn’t the Answer: The Case for Optimal Tension
In my second article for RunRepublic, I want to talk about a common assumption among runners (and the population in general): that stiffness is always bad and flexibility is always good.
For many of us growing up, this idea was introduced early (often by our first PE teacher) and repeated so often we stopped questioning it. Tight calves? Stretch them. Tight hamstrings? Stretch them. Stiff hips? Stretch them again. Flexibility, we were told, is always positive. (Yes, some of us may have heard of “hypermobility,” but that was usually dismissed as a rare risk.)
But what if this isn’t the full story? What if, in many cases, the stiffness you’re trying to stretch away is actually an adaptation your nervous system has placed in your body for your own good?
Why your nervous system makes you stiff
In my experience as a coach and an athlete, stiffness usually appears for one of two reasons:
- Positions. If you spend hours every day sitting, your hips will tighten. Not because they are “broken,” but because your body adapts to the shape you put it in most often. The fix is not endless stretching of the hips, but breaking the pattern of the chair or other positions you hold too long, too often.
- Weakness or instability. The body is clever. When a joint is unstable or weak, the nervous system limits its range of motion to protect it. That “tight” hamstring you curse is not your enemy but more like a safety brake.
This logic extends beyond running. Thinkers such as Dr. Thomas Cowan have suggested that lowered testosterone in older men may not be simply a function of age, but the body’s way of limiting output so that you can’t act beyond your structural capacity. In other words: weakness drives restriction. When the foundation isn’t strong, the body reins itself in.
The trap of chasing flexibility first
Like many runners, my first attempt at addressing limited mobility or flexibility was the drudgery of nightly stretching, rolling, and “release” drills: often still the same old classics taught to us by a series of PE teachers. Sometimes I felt looser, briefly. But inevitably the stiffness returned, or, even worse, one area loosened only for another area to tighten up.
It was only when I committed to systems that focused on building strength through natural, integrated movement that I saw real progress. Whenever I drifted from that approach, or slipped back into chasing symptoms with reactive treatments, improvement slowed: or stopped altogether.
I first encountered these ideas over a decade ago through brilliant coaches like Tony Riddle and Lee Saxby. Their emphasis on natural movement showed me that mobility and strength emerge together when you train the body as a whole, not as isolated parts. Later, a consistent focus on strength rather than mobility drills confirmed the lesson again. And this year, I experienced it yet another time: when I dropped all my mobility routines (simply because I no longer had the time), swimming alone left me moving and feeling much better and stronger.
In every case, the pattern was the same: when I trusted natural, integrated strength work, my mobility improved as a byproduct. When I didn’t, progress stalled.
My first experience of this was through various natural movement training systems (like MovNat) or philosophies that encouraged us to pay attention to how often we get “stuck” in static positions and then applying focus on breaking up those long spells stuck in these positions. Some people talk of 'movement snacks' but if that sort of language is not your cup of tea, it is simply the idea that we are not designed to be locked into one position (especially in a chair or car) for hours on end. Ido Portal coined a good phrase in answer to 'what's your best position' when he said 'your next one'. Moshe Feldenkrais (inventor of the Feldenkrais technique) popularised the more known saying 'movement is life, life is movement'. As runners there should be an instinct attraction to that phrase because most of us do struggle to stand still!
But doing things blindly is not enough. What we know now is that chasing more mobility or flexibility in isolation often backfires. The body is a tensegrity structure, where stability comes not from rigid beams but from a balance of tension and compression across the whole system. Think of a geodesic dome or one of those children’s toys made of elastic strings and sticks: push or pull in one place, and the entire shape shifts to redistribute the load.
The human body works the same way. Muscles, tendons, and fascia form a continuous web. Bones, while load-bearing, also act like spacers and levers that keep the web in shape. When one area is pulled tight, another has to adjust to keep the whole system balanced. This is why trying to “fix” a single tight muscle in isolation rarely works: the tension just moves somewhere else.
What runners really need: optimal tension
Before anyone protests, I am not saying that mobility is bad. Rather, it’s that we must stop thinking in simple binaries: stiffness bad, mobility good. What we are truly chasing is optimal tension: the tuned stiffness that makes our lower legs feel bouncy and springy when we run. Too loose, and we lose efficiency (this is when it feels like you are running on flat tires, or you have to work extra hard to get off the ground). Too tight, and you still risk injury.
Routines that respect this principle already exist. The RAMP protocol (Raise, Activate, Mobilise, Potentiate) is one well-known warm-up method. Peter Matthews’ priming work for runners is another—he has presented widely for Athletics Ireland and other associations on this topic. These protocols do not aim to make you floppy but to prepare your system with the right level of tension.
What you are trying to avoid is what the crew over at Functional Patterns calls hyperflaccidity—their term for when the body becomes so loose and de-tensioned from excessive stretching or mobility work that it loses the spring, stability, and efficiency needed for powerful, coordinated movement. For runners, this can look like the athlete who stretches their calves endlessly, only to find they’ve lost the bounce in their stride and feel flat on the road instead of elastic. In running terms, they’ve undermined optimal leg stiffness; what Steve Magness calls “muscle tuning”, which is essential for storing and releasing energy efficiently with every step.
In practice, it can be as simple as this:
- Warm up dynamically. Light jogs, skips, lunges, leg swings, strides.
- Strength work 2–3 times weekly. Single-leg squats, calf raises, split squats, hip hinges. Build stability where you can feel you are most unstable (often in one-legged positions).
- Integrate natural movement. Swimming, crawling patterns, or light plyometric drills. These remind the body how to coordinate strength and mobility together.
Stretching can still play a role: but not as the main act. Think of it as a supplement, especially after extreme exercise (such as running an ultra), not the mainstay protocol for keeping your body in perfect condition.
Closing Thoughts
If you want to spend your time productively making yourself more durable as a runner, it is worth focusing on strength and natural movement instead of pouring all your discipline into an isolated stretching routine. Systems like MovNat were built on this very principle: when you move dynamically and naturally, strength and mobility grow together. When we break the body into parts, we break the athlete.
As runners, we don’t need maximum mobility. We need tuned, resilient, spring-like tension. That’s what makes us efficient, powerful, and safe. It’s also more “bang for our buck”: when I invest 30 minutes into a natural activity (like swimming) or a set of exercises that mimic these natural movements (always against some form of resistance, and thus building strength), I get both stronger and more mobile. When we focus on flexibility in isolation, we only get looser—leaving strength to be taken care of separately. And we are all busy people with other commitments than keeping ourselves ready to run.
So the next time you feel stiff, don’t just ask, “how do I get looser?” Ask instead: “what does my body not trust me to do yet?” Build that trust through strength, and you may find the freedom of movement you’ve been chasing all along.
