For years, the ritual felt non-negotiable: trainers at the gym pressed it, schoolteachers required it, running magazines illustrated it. Stand on one leg, pull the other heel to your backside, count to thirty, repeat on the other side, and head out the door. Static stretching before a run seemed like the responsible, sensible thing to do. Then a sports physiotherapist sat down with me and a fairly recent body of research, and the conversation changed Everything/”>Everything I thought I knew about what was happening inside my muscles during those roadside rituals.
Key takeaways
- Static stretching holds over 60 seconds reduce muscle power by up to 4.6% and weaken your nervous system’s ability to recruit muscle fibers
- Your tendons work like springs during running; static stretching dampens this elastic recoil, removing ‘free’ propulsion energy
- Dynamic warm-ups—controlled movement through full range of motion—prime your muscles and central nervous system instead of quieting them
What static stretching actually does to a muscle before you run
The physiology here is genuinely counter-intuitive. In terms of peripheral mechanisms, static stretching affects the musculotendinous unit (MTU), and among the main physiological factors suggested to explain altered muscle functioning are changes in viscoelastic properties of the MTU, which result in increased compliance and a subsequent decrease in MTU stiffness. That word, stiffness, is the crux of it. Not stiffness in the uncomfortable sense of a seized-up back, but mechanical stiffness: the ability of your tendons to act like a spring.
A stiffer tendon facilitates the rapid return of stored elastic energy during the stretch-shortening cycle, potentially reducing the metabolic cost of running by decreasing the reliance on active muscle contractions. Every footstrike stores energy in your tendons; every push-off releases it. This elastic recoil is essentially free propulsion, and static stretching blunts it. This may impair Performance-and-sleep/”>Performance of tasks conducted in the stretch-shortening cycle, and increased MTU compliance could lower the elastic potentiation produced during the stretch phase of these activities.
There is also a neurological dimension that rarely gets discussed outside a clinical setting. Research suggests that the reduction in force after static stretching may be due to mechanisms occurring within the nervous system, with one hypothesis being that it results from a reduction in the motor command from the central nervous system to the muscle. In plain terms: your brain temporarily becomes less efficient at recruiting the muscle fibres you need. Static stretching decreases motor neuron excitability through an inhibitory effect from the Golgi Tendon organ, and also decreases the activity of muscle spindles, which results in decreasing the activity of the stretch reflex. The stretch reflex is, in essence, the automatic muscular response that keeps you upright and propulsive when your foot hits the ground. Quietening it right before a run is a counterproductive trade-off.
The duration problem: where the research draws a line
The picture is not entirely black and white. Duration turns out to matter enormously. Holding static stretches for longer than 60 seconds may reduce muscle strength and power for a few minutes, though this is not permanent; holding a stretch for less than 60 seconds does not affect muscle function, especially if it forms part of a well-rounded warm-up that includes sport-specific movements.
Research shows that static-stretching-induced performance changes were small to moderate when testing was performed immediately after stretching, with a clear dose-response relationship: stretches of 60 seconds or more produced performance deficits of around 4.6%, compared to just 1.1% for stretches shorter than 60 seconds per muscle group. Those figures may sound modest, but over a 10-kilometre race they translate into meaningful seconds, and they compound across a training week.
The situation is further complicated when we consider running economy specifically. A 2025 systematic review with meta-analysis found that overall, stretching did not significantly affect running economy acutely, suggesting the effect varies considerably between individuals and protocols. One study in the review noted that less flexible runners appear to gain greater benefits from stretching than athletes with normal flexibility, and that for this group, aiming for an optimum amount of flexibility would likely result in a more economical run. If your hips are genuinely restricted from a desk-bound working day, a brief static stretch before running may actually help rather than hinder you.
The case for dynamic warm-ups
The alternative that sports physiotherapists now broadly favour is dynamic stretching, controlled, repetitive movement through your joints’ full range of motion. Dynamic stretching mimics the activity you are about to perform, helping to rehearse movement patterns so the muscles “get excited a little bit earlier and faster,” which can help improve power and increase coordination. Leg swings, walking lunges, high knees and hip circles are the unglamorous bread-and-butter of a proper running warm-up.
Dynamic warm-ups have gained traction as a preferred approach over static stretching because of their increased potential to improve athletic performance and reduce injury, by enhancing musculoskeletal, neurologic, cardiovascular, and psychological systems before performance. The contrast with static stretching is stark: where static holds temporarily dampen neural drive, movement-based warm-ups actively prime it. Static stretching relaxes muscles and reduces blood flow while decreasing central nervous system activity, whereas active warm-up exercises, especially those involving dynamic stretching, have the opposite effect, boosting blood flow, activating the central nervous system, and enhancing strength, power, and range of motion.
The practical upshot for most recreational runners is a shift in sequencing. Dynamic stretches are best done before a workout, as they prime the muscles you are going to use by simultaneously increasing blood flow, flexibility, and range of motion, while static stretches are best reserved for after a workout or performance during the cool-down period. Five to ten minutes of controlled movement, not a passive stand-and-hold, before lacing up properly. The static work belongs at the end.
What about injury prevention?
This is where many runners feel the most resistant to changing their habits. The idea that stretching guards against injury is deeply embedded in popular exercise culture, and it turns out to be largely unsupported by the evidence. A 2025 international Delphi consensus panel of 20 experts concluded that while there is no evidence a single bout of stretching can reduce injury risk or incidence, chronic stretch training is one of the most often cited methods for injury prevention — yet the scientific evidence does not provide clear support for its application.
Considering the small-to-moderate changes immediately after stretching and various study limitations, stretching within a warm-up that includes additional post-stretching dynamic activity is recommended for reducing muscle injuries and increasing joint range of motion with inconsequential effects on subsequent athletic performance. The key phrase there is “additional dynamic activity”, not static holds alone.
The more useful question for injury prevention may not be “how long should I stretch?” but “what else am I doing?” A review of available scientific literature found that strength, stability, and postural control interventions were the interventions most beneficial for moderating injury risk. A single-leg calf raise, done consistently over weeks, likely does more protective work than a 30-second hamstring hold ever could. That, perhaps, is the inconvenient truth about the ritual so many of us have faithfully performed for years: the time might simply be better spent.
One genuinely useful context where static stretching retains real value is long-term flexibility. Static stretching effectively increases flexibility and range of motion, and has been shown to be more effective than dynamic stretching in improving flexibility over time. The American College of Sports Medicine recommends stretching each of the major muscle groups at least two times a week for 60 seconds per exercise, as a standalone practice, separate from your run. Done in the evening, after a workout, or on a rest day, that same quad stretch or hip flexor hold that was potentially blunting your sprint capacity becomes genuinely beneficial. Context, not the stretch itself, determines whether it helps or hinders.
As always, if you have a specific injury, ongoing muscle pain, or concerns about your flexibility and training, consult your GP or a qualified physiotherapist for personalised advice.
Sources : mdpi.com | pmc.ncbi.nlm.nih.gov