why pnf assisted stretching is the secret weapon every london marathon runner needs
You have put in the miles. You have rearranged your work day and weekends around your long runs. You are building toward something genuinely demanding and an incredible achievement. The question is not whether you can finish the London Marathon. It is whether your body will let you run it the way you are capable of running it.
Most runners invest everything in the training plan and almost nothing in what happens to their muscles along the way. Tightness builds, range of motion shrinks, movement patterns compensate, and by the time the hard weeks arrive, the body is already under strain it was never prepared for.
That is where your running injuries come from, and that is exactly where PNF assisted stretching changes the picture completely. Not gently, gradually, over months of hoping. Immediately, measurably, from the very first one-on-one assisted stretch session.
“If anyone tells you its normal to experience some discomfort and pain in assisted stretching - walk away immediately. It’s counter productive. Try PNF assisted stretching instead. Your body will thank you.”
What Your Body Is Actually Doing When You Run
Running is deceptively demanding. Each stride calls on an intricate chain of muscles working in precise sequence. Your hamstrings, hip flexors, glutes, calves, and iliopsoas are the primary movers, while your core and thoracic spine work continuously to stabilise your entire frame.
Research published in the Journal of Biomechanics confirms that the hamstring group is under particular stress, functioning as both a decelerator of the swinging leg and a propulsive force at toe-off. This dual role means your hamstrings are working eccentrically and concentrically within the same stride cycle, hundreds of thousands of times over a marathon training block.
It is no coincidence that hamstring strains are among the most common injuries in distance runners. A 2018 review in the British Journal of Sports Medicine found hamstring injuries account for up to 29% of all running-related muscle injuries, with recurrence rates above 30% when the underlying restriction in range of motion is not properly addressed.
The hip flexors tell a similar story. Tight hip flexors alters your pelvic tilt, loading the lumbar spine and reducing stride efficiency. Restricted calves change your foot strike pattern. These are not isolated problems; they cascade through the kinetic chain, and the further you run, the more pronounced the effect becomes.
Why Static and Dynamic Stretching Fall Short
The two most common approaches to flexibility in a runner's routine are static stretching (holding a position for 30 to 60 seconds) and dynamic stretching (controlled movement through a range like walking hamstring stretches). Both have their place and dynamic before a run is definitely advised, but neither addresses the fundamental reason why muscles remain restricted in well trained athletes.
The issue is not solely the muscle tissue itself. It is the nervous system.
Your muscles have a built-in protective mechanism called the stretch reflex, governed by proprioceptors called muscle spindles. When a muscle is lengthened quickly, the spindles fire and the muscle contracts to protect itself from tearing. Static stretching can partially override this over time, but it works slowly and the neurological "ceiling" on your flexibility remains largely intact. Dynamic stretching is excellent for warming up joint range and preparing movement patterns, but it does not create lasting change in tissue extensibility either.
Furthermore, aggressive stretching that causes pain is actively counterproductive. If anyone tells you ‘it’s normal to hurt’ walk away immediately! When you experience discomfort during a stretch, your body responds by creating micro-tears in the muscle fibres. The repair process that follows involves your body contracting and stiffening the tissue to protect it. You end up tighter than you started.
This applies equally to sports massage techniques that work deeply and painfully into restricted tissue: they may feel productive in the moment, or feel like a necessary discomfort, but the micro-damage they create triggers exactly the inflammatory and protective response you are trying to reverse. More stress on already stressed muscle fibres is not the answer.
The Science Behind PNF: Working With Your Nervous System, Not Against It
Proprioceptive Neuromuscular Facilitation, PNF, was developed in the 1940s and 1950s by Dr Herman Kabat alongside physiotherapists Maggie Knott and Dorothy Voss. It was originally designed as a rehabilitation tool for neurological conditions. Over more than 70 years of clinical application and research, it has evolved into the most evidence-backed flexibility method available and is why we at Stretch Life, chose to specialise in this powerful and effective method.
Where static stretching tries to override the stretch reflex, PNF works intelligently with the nervous system to genuinely reset the muscle's resting length.
The mechanism works through two physiological principles. The first is autogenic inhibition. When a muscle contracts against resistance, it activates receptors in the tendons called Golgi tendon organs. These organs send a signal to the spinal cord that causes the muscle to relax. In a PNF session, your physio-trained therapist takes you to the point of stretch, then asks you to contract the muscle isometrically against their resistance for several seconds. When that contraction releases, the Golgi tendon organs trigger a deeper, neurologically facilitated relaxation, allowing the muscle to lengthen further than it could through passive stretching alone.
The second principle is reciprocal inhibition. When you contract the muscle opposing the one being stretched, your nervous system automatically signals the target muscle to relax. A skilled PNF therapist uses both mechanisms in combination, creating layered neurological release that no amount of static holding can replicate.
A 2012 meta-analysis published in the Journal of Human Kinetics compared PNF, static, and dynamic stretching across multiple measures. PNF produced significantly greater improvements in hamstring flexibility than either alternative, with gains maintained over time rather than regressing between sessions. A 2020 study in the International Journal of Sports Physical Therapy specifically examined distance runners and found that eight weeks of PNF stretching produced a 22% improvement in hamstring extensibility, along with measurable reductions in injury incidence.
Elite athletes have understood this for years. The stretching routines of professional football clubs, Olympic sprinters, and international rugby sides increasingly incorporate PNF work precisely because it delivers neurological reprogramming rather than temporary tissue lengthening.
Gentle on the Body. Immediate in Its Impact.
This is the part that surprises most runners. You come in tight and tense. You leave with noticeably more range of motion immediately. Not after six weeks of sessions, not after a month of consistency, though those results compound beautifully. After the very first one-on-one stretch appointment.
Because PNF works at the level of the nervous system rather than forcing tissue, your muscles are not being pushed, ground down, or broken to create change. They are being neurologically reprogrammed to release. The difference is not subtle. Runners routinely walk out of their first session and feel their hips moving freely in a way they had forgotten was possible. Hamstrings that have been locked for weeks begin to open up. It is not a pleasant sensation that fades by morning. It is a genuine, measurable shift in what your body can do.
There is no discomfort involved. No grimacing through a deep tissue technique, no bruising, no day of soreness afterwards. Your physio-trained therapist guides every movement, your body does the work, and the results speak immediately.
This also means sessions fit around your training without adding to your fatigue load. You can have a session the day before a long run, or the evening after a hard track session, and wake up feeling better for it rather than worse. That is simply not something sports massage or aggressive stretching can offer.
The contrast is worth being direct about. Deep tissue massage can be useful for many things, but when it causes pain, it is creating micro-tears in muscle fibres. Your body's response to those tears is to lay down scar tissue and contract the surrounding tissue to protect itself. You may feel temporarily looser as inflammation reduces muscle tone for a day or two, but the underlying restriction returns, and often deepens. Stretch Life takes a different position: there should be no pain in a stretching session, ever. Pain is a signal that tissue is being damaged, and the last thing a marathon runner needs is more damage to repair.
Why Regular Sessions Change Everything
A single PNF session produces measurable improvement. But the real transformation comes from consistency. The nervous system learns through repetition, and each session builds on the neurological patterns established in the last. Over four to eight weeks of weekly or twice-weekly sessions, the resting length of chronically tight muscles genuinely changes. The hip flexors stop pulling on the lumbar spine. The hamstrings recover their full range. The calves stop restricting dorsiflexion and altering your gait.
For a marathon runner in training, this has compounding benefits. Better hip extension means longer, more efficient strides. Proper hamstring length reduces the eccentric loading that leads to strains. Improved calf flexibility reduces the risk of Achilles tendinopathy, plantar fasciitis, and the calf tears that end so many training blocks prematurely.
You also recover faster. Muscles with full range of motion under load accumulate less metabolic waste and repair more efficiently. The morning after a long run, your legs will feel noticeably less seized.
The Right Time Is Now
The London Marathon is in April. If you start weekly PNF sessions now, you have the training window to build genuine, lasting change in your flexibility before the hardest weeks of your programme arrive. Leave it until March, and you are managing problems rather than preventing them.
Two 25 minute sessions a week will accelerate your results. One 50 minute or 75 minute session a week will also make a meaningful difference. The key is consistency, and the good news is that because sessions are gentle and restorative, they fit easily around your training without adding to your fatigue load.
Stretch Life: London's Only PNF Specialists
Stretch Life are London's only dedicated PNF specialists, with studios in Waterloo and Islington. Every session is one-on-one with a physio-trained therapist who understands exactly what a running body demands and where it breaks down. Your session is not a generic stretch routine. It is tailored to your specific restrictions, your training load, and what your body needs most right now.
This is not a stretch class, a yoga-inspired flexibility session, or a general sports massage. It is precise, evidence-based work rooted in more than 70 years of clinical research, delivered by therapists who know how to produce results you will feel immediately and build on over time.
If you are running London this April, your legs deserve better than guesswork. Let the science work for you.
Book your first session at Stretch Life, Waterloo or Islington, and find out what your body is actually capable of.
Feel the Stretch Life difference at our Islington or Waterloo studio now.
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