Stretching – Knowledge

1. Why this article?

Few things are done as automatically and questioned as rarely as stretching. A quick reach for the toes before a run, a circle of players pulling at their hamstrings after football training, something for the stiff back in the morning. Almost everyone was taught it – hardly anyone was ever told what for.

In the clinic we hear the same three sentences almost daily. "I should stretch more." "My back hurts because my hamstrings are short." "I didn't stretch enough, that's why I tore something." All three sound sensible. And none of them holds up in the way it is meant – although the third, as will become clear, is less firmly refuted than the other two.

Yet stretching is one of the most thoroughly studied topics in exercise science. There are hundreds of controlled trials, several large syntheses and two Cochrane reviews – particularly careful evaluations of every study available on a question. The results are remarkably consistent. And they sit rather awkwardly next to what most of us were taught.

The short version first: stretching makes you more flexible – that is well established. It does not prevent muscle soreness, it does not demonstrably lower the total number of sports injuries, it lengthens muscles only at very high doses, and it does not release tension in any literal sense. But there are situations in which it very much works, and few people know them.

This article explains what actually happens in the body during a stretch, what the different techniques are and how they differ, what the studies say about the familiar promises, when stretching is genuinely indicated – and what helps instead when it is not. Every statement is referenced; the numbers in square brackets point to the reference list at the end.

One note in advance: this article does not replace individual advice. Anyone with a specific diagnosis, recent surgery or a neurological condition involving muscle stiffness will be given a recommendation tailored to that situation – and it takes precedence over everything described here.

2. What actually happens when you stretch

The common picture goes like this: a muscle is too short, you pull on it, it gets longer. Like a rubber band you stretch out. That picture is vivid and it is everywhere – but it captures at most a small part of what actually happens.

2.1 Mostly you tolerate more – and a little of the muscle does grow

If you stretch regularly for six weeks, your range of motion will increase measurably. Nobody disputes that. The only question is: why?

There are two possible explanations. Either the tissue has changed – the muscle really has become longer or more compliant. Or your body has learned to tolerate the end position better: the same tension feels less threatening, so you allow the movement to go further. The technical term is stretch tolerance.

The two explanations can be told apart, because both can be measured: stiffness (a device moves the joint into a defined position and records the force required) and the architecture of the muscle itself. For the latter, ultrasound is used to look at the fascicles – the bundles into which muscle fibres are grouped. If they get longer, that points to a structural change – most plausibly to more sarcomeres lying end to end; sarcomeres are the smallest units capable of shortening. In a living human they cannot be counted, though: ultrasound measures the length of the bundle, not the number of building blocks within it. It would still be genuine lengthening.

The tolerance side. A six-week stretching programme for the calf clearly increased range of motion – while the stiffness of muscle and tendon, fascicle length and pennation angle all remained unchanged [3]. A review of the mechanical properties reached the same conclusion: in healthy people and with programmes of three to eight weeks, they do not change reliably [4]. That flexibility nonetheless increases was attributed in a widely cited 2010 paper to altered sensation [1]. For a long time that was the answer to the question.

The other side – and it is stronger than that answer suggested. A 2023 meta-analysis evaluated 19 studies with 467 participants specifically on muscle architecture, with high confidence in the cumulative evidence. The result: static stretch training does increase fascicle length – slightly at rest, somewhat more clearly during stretching [5]. So the muscle does become somewhat longer after all.

What matters, though, is the subgroup analysis in the same work: the increase appeared only with high stretching volumes and high stretching intensities. With low volume and low intensity – which is what most people do – there was no change at all, and the difference between these subgroups was statistically meaningful. The more and the more intensely people stretched, the more the fascicles grew [5]. What "high" means is shown by the study that had young volleyball players stretch for twelve weeks: it raised the stretching time from nine to fifteen minutes per leg per session, five times a week [7].

The two mechanisms were set side by side most cleanly in a study of the calf muscles: three weeks of twice-daily stretching increased range of motion by almost 20 per cent. This was carried both by a 28 per cent higher tolerated torque at the end of range – that is, by tolerance – and by measurable lengthening of the muscle and its fascicles with 18 per cent lower stiffness [6]. It is not an either-or.

What follows from this: at ordinary doses tolerance is the larger share – if you stretch for a few minutes a week, you gain flexibility mainly because sensation changes. Tissue changes as well, but only at a dose considerably above what is done in everyday life. "My muscle is too short" therefore usually remains the wrong description of the problem – and other routes to the same flexibility remain conceivable, see section 8.

2.2 What happens in a single session – and how fast it fades

While you hold a stretch, something mechanical really does occur: tension in the tissue falls even though the length stays the same. Anyone holding a stretch for thirty seconds notices it – after ten seconds it pulls less than at the start.

The effect is real, but fleeting. In a classic study of the hamstrings, five consecutive stretches produced a measurably lower resistance – an hour later nothing of it remained [2]. A more recent study tracked the course after a five-minute stretch step by step and found the same: the changes in muscle and tendon largely reversed within the following hour [11].

That explains an apparent contradiction: the single session fizzles out, and yet flexibility increases over weeks. The mechanical changes of one session do not simply add up from day to day. What builds up is chiefly habituation to the end position – plus, at a sufficient dose, the tissue remodelling described in section 2.1.

2.3 The top end of the dose – and why it is irrelevant for everyday life

Take the dose–response relationship described in section 2.1 to its extreme and you arrive at something that has caused a stir in recent years. In one study participants stretched their calf muscles for six weeks, one hour a day, in a splint. The result: more range of motion, more strength and a measurably thicker muscle [35]. A synthesis of several such studies confirmed the relationship and at the same time showed what it depends on: the effect only appears at very long stretching durations, far beyond what people normally do [36].

On the broader question of whether stretching can build muscle, an earlier review had already noted that the human evidence is very thin; the striking findings came from animal experiments with continuous stretch over weeks [34].

Some perspective. Stretching for an hour a day to build a little muscle – the same hour spent on strength training yields a multiple of that. These studies are scientifically fascinating and practically almost meaningless. If someone offers them as an argument for stretching, you are entitled to ask about the dose.

3. The techniques – and what separates them

"Stretching" is an umbrella term for four rather different things.

3.1 Static

The best-known form: you move into an end position and hold it. Fifteen, thirty, sixty seconds. This is the technique most studies are about – and the one meant when "stretching" appears below without further qualification.

3.2 Dynamic

You take the movement in a controlled way to its end point and back again, several times over: leg swings, big arm circles, lunges with a trunk rotation. Nothing is held. This is not a variant of static stretching but rather a warm-up with a large range of movement – and that is exactly where its value lies (see section 6).

3.3 Contract and relax (PNF)

The abbreviation stands for "proprioceptive neuromuscular facilitation" – an unwieldy name for a simple procedure: you move into the stretch position, contract the stretched muscle against a resistance for a few seconds, let go, and then move a little further. Usually a second person is needed.

This technique produces the largest short-term gains in range of motion [9]. In a large synthesis of immediate effects, static stretching and PNF came out level at the top, with dynamic stretching behind them [8]. The price is effort – and the same temporary loss of strength as with long static stretching.

3.4 Ballistic – bouncing

Springy, swinging movements at the limit of the range. Once widespread, rarely recommended today: the gain is no greater than with the other techniques, while the peak loads on the tissue are. Anyone with an irritated tendon or a recent injury is better off leaving it alone.

3.5 The foam roller

Strictly speaking the foam roller does not belong to stretching, but it is mentioned in the same breath and claims the same effects. So, briefly: it increases range of motion immediately after use – less than stretching does, but without costing any strength. On how the muscles feel after training it has a mildly positive effect, on performance practically none [43]. Applied over weeks it increases range of motion as well; that became clear only in programmes running longer than four weeks, and not at every joint – at the hamstrings and quadriceps yes, at the ankle no [44].

What it certainly does not do is "release" connective tissue or undo adhesions. The roller generates neither the forces nor the exposure time that would be needed. What it does generate is a strong signal to the nervous system – and that is apparently enough to shift the limit of movement for a while. As preparation for training it is a useful tool.

4. What stretching demonstrably does

4.1 More flexibility – here it is undisputed

On this point the evidence comes down clearly in favour of stretching. All techniques increase range of motion immediately, and regular stretching over weeks increases it lastingly [8], [10].

The dose is the interesting part. An analysis comparing technique against duration found that what counts is the total time per week, not the length of the individual stretch. From about five minutes per week per muscle group onwards, the gains became clearly larger [10]. Five minutes a week is ten stretches of thirty seconds – spread across the week, a manageable affair.

The largest analysis of this question so far – 189 studies with 6654 adults – draws the line at the upper end. It found the gains maxed out at around ten minutes per week, and at about four minutes within a single session; beyond that, more stretching added nothing. What is striking is what made no difference in that work: neither intensity nor the number of sessions per week, neither age nor sex nor training status. The people who gained most were those who were least flexible to begin with [49].

Between five and ten minutes per week per muscle group lies the whole useful range – five minutes is the threshold at which something happens, ten is the end of the line.

So if you want or need to become more flexible, stretching is the right choice. That is the effect it is made for.

4.2 How long the effect lasts

Two time scales need to be kept apart, and confusing them causes a great deal of muddle.

• After a single stretch: the gain is largely gone within half an hour to an hour [2], [11]. Stretching in the morning so that things go better at sport in the evening is wasted effort.
• After weeks of regular stretching: the newly gained flexibility stays – as long as it is maintained. If you stop, it recedes over weeks to months, much like strength and endurance.

Flexibility is therefore not something you acquire once and then own. It is a property that wants to be maintained – but maintaining it costs far less time than building it.

5. What stretching does not do

Now for the less comfortable part. Three of the best-known justifications for stretching have been examined, and thoroughly.

5.1 Muscle soreness

The Cochrane review on this brings together twelve studies with more than 2500 participants. The result: stretching before or after exercise does reduce soreness – but so little that nobody notices. Converted to a pain scale from 0 to 100, the difference on the following day was about one point [15]. An earlier analysis by the same group had reached the same conclusion [14].

One point out of a hundred is not a perceptible effect. If a long downhill hike has you taking the stairs backwards for two days, stretching will not prevent it.

5.2 Injury prevention

Here matters are more layered – and they have shifted somewhat in recent years.

The most informative single study comes from the Australian army: 1538 recruits, twelve weeks, one half stretching before every training session, the other not. Injuries: 158 versus 175 – no meaningful difference [16]. A Japanese study of 901 recruits found a somewhat different picture: the total number of injuries was the same, but muscle and tendon injuries and back pain occurred less often in the stretching group [17].

The large synthesis of all prevention studies puts this in context. It compared the different approaches and found that strength training cut the injury rate to less than a third, and balance and coordination training to about half. Stretching showed no meaningful effect [18]. A later analysis by the same group confirmed the effect of strength training and additionally found a relationship with the amount: more strength training, fewer injuries [19].

For muscle injuries specifically, though, the picture has become less clear-cut. A 2024 meta-analysis pooled precisely those trials that recorded muscle and tendon injuries separately. Muscle injuries were markedly less frequent in the stretching group; for tendon injuries no such difference appeared [50]. But of more than five thousand records screened, exactly four trials remained, three of them with data on muscle injuries. A reply published in the same journal holds that against the work – a preventive effect cannot be derived from so few studies [51]. And a consensus paper in which twenty researchers in the field aligned their assessments over several rounds concluded in 2025 that stretching is not a comprehensive injury prevention strategy [52].

So both things hold at once. Stretching does not reliably lower the total number of sports injuries – that is the robust part. That it may nonetheless do something for certain muscle injuries is possible and should not be suppressed; but the evidence for it is far thinner than that for strength training and for complete prevention programmes.

How large the difference can be is shown by the most common muscle tear in sport, that of the hamstrings. Prevention programmes that regularly included the Nordic hamstring curl – in which you lower yourself slowly forwards from a kneeling position – halved the injury rate in a synthesis of studies covering 8459 athletes [20]. What is established is therefore the effect of programmes containing that exercise, not of the exercise on its own, and certainly not of doing it occasionally. For a stretching programme, an effect of that magnitude has not been shown. More on this in our article on hamstring injuries.

A fair caveat: there is one argument in favour of stretching, and it does not come from the incorrigible. Sports with a great deal of rapid braking and jumping – football, handball, sprinting – demand something different of the muscles than cycling or jogging, where they never work at extreme angles. For the first group there are indications that stretching might reduce the rate of muscle strains; for the second no effect is to be expected [21]. The distinction is plausible, fits what the 2024 meta-analysis suggests [50] – and to this day is insufficiently tested. It does not change the order of priorities: if you want to prevent injuries, start with strength.

5.3 Contractures – the sobering result in the medical field

A contracture is a lasting restriction of movement at a joint, of the kind that develops after long immobilisation, after a stroke or in neurological conditions. This is precisely what stretching has traditionally been used against – often with splints, for hours, over months.

The Cochrane review on this evaluated 49 studies and reaches an unambiguous conclusion: stretching has no clinically meaningful effect on joint mobility in people with contractures or at risk of them. The mean difference was around two degrees – a magnitude nobody notices in daily life. Nor was any meaningful effect found on pain, activity limitation or quality of life [30].

That is an uncomfortable result, because a great deal of therapy time has gone into this treatment. It does not mean that nothing can be done about restricted movement – it means that passive stretching alone is not the answer. What remains: active movement through the whole available range, strength training into the end positions, considered positioning, and treatment of the underlying condition.

6. Stretching before sport

This is the question asked most often – and the one on which most has changed in twenty years.

6.1 What long static stretching does to strength

From the late 1990s onwards, study after study showed the same thing: those who stretch statically at length before a strength or jump test perform worse. The explanation is largely neural – for a while the nervous system drives the stretched muscle less strongly – and only to a smaller extent mechanical [27].

Duration is decisive. An analysis of more than a hundred studies found that with stretches of up to sixty seconds per muscle the average loss was about one per cent – which is nothing. With stretches of more than sixty seconds it rose to around five per cent [23]. Other reviews arrive at the same magnitude and the same threshold [22], [24].

A one per cent loss of strength matters to nobody in recreational sport. If you hold a stretch for thirty seconds, there is nothing to worry about.

6.2 Why a complete warm-up absorbs almost all of it

The more important finding came later. The early studies had a design flaw: participants stretched and were then tested immediately. Nobody in sport does it that way.

In a carefully designed study, physically active men completed a full warm-up – easy jogging, stretching (static, dynamic or none at all), then sport-specific drills of increasing intensity. Afterwards: sprint, jump and change of direction. The result: no difference between the groups [26]. If warming up continues after the stretching, the effect disappears.

A review that took up precisely this point came to the same conclusion: the decrements are small, occur mainly with long stretching durations and are largely offset by subsequent dynamic activity [25].

The old warning "whatever you do, don't stretch before sport, it costs performance!" is therefore outdated in that severity. It holds for long static stretches immediately before the starting gun. It does not hold for a short stretch in the middle of a proper warm-up.

6.3 What a sensible warm-up looks like

That warming up itself works is well established: a synthesis of the studies found an improvement in roughly four out of five performance measures examined [28]. A workable structure:

• Get generally warm – five to ten minutes of easy running, cycling or skipping. Until your breathing is going and your skin is warm.
• Move dynamically – leg swings, lunges, arm circles, hip openers. The range of movement the sport requires is actively taken through.
• Static stretching, if you want it – short, under thirty seconds, targeted at the places the sport demands. Optional.
• Get sport-specific and fast – accelerations, jumps, passes, strokes, with rising intensity up to near the pace about to be required. This step is the one most often left out and the most important.

Dynamic stretching is the more obvious choice within this structure, because it warms you up at the same time. For the technique on its own, however, no protection against injury has been demonstrated – a review examining exactly this question found plausible mechanisms but no robust data [29]. That is a different question from the warm-up programme as a whole: complete programmes containing strength, jumping and balance work do lower the injury rate [18], [20]. A few leg swings on their own are good preparation, not a shield.

7. Stretching after sport

Briefly and honestly: no benefit for recovery has been demonstrated. Not against soreness [15], not for next-day performance. The cool-down with a stretching routine is a ritual, not a mechanism.

But there is equally nothing against it. If you like stretching after training because it feels good, because it marks the transition back into everyday life or because that is what the team does – then do it. It does no harm, it costs five minutes, and if you want to become more flexible anyway, it is exactly the right opportunity: the muscle is warm and the time is there.

Only nobody should believe they are preventing something. Recovery is decided by sleep, nutrition, training planning and the distribution of load – not by the last five minutes.

8. Strength training also makes you flexible – and rather more besides

This finding surprises most people and is in practice the most useful in the whole article.

A synthesis of studies that compared strength training and stretching head to head found that both increase range of motion, and to a comparable extent [31]. The condition is that training goes through the full range of motion – the deep squat rather than the half one, the fully extended lowering rather than a short jerky movement.

The braking part of an exercise is particularly effective here, the so-called eccentric load: the muscle works while it is lengthening – walking down stairs, lowering a weight slowly. A review concluded that eccentric training increases lower-limb flexibility at least as well as stretching [32].

Conversely, the old worry that stretching makes you weak no longer applies: regular stretching over weeks does not harm strength [33]. The loss described in section 6.1 is a matter of minutes, not a lasting effect.

What follows from this? If strength training delivers the same flexibility and prevents injuries [18] and preserves bone, muscle mass and everyday capability – then with limited time it is clearly the better choice. Stretching remains sensible where flexibility is needed beyond what strength training supplies. How to build such training is described in our article on strength training.

9. When stretching is genuinely indicated

After so many qualifications the impression might arise that stretching is pointless. That would be wrong. There are clear situations in which it is precisely the right tool.

9.1 A real, measured restriction of movement

If a joint genuinely allows less movement than the other side and this interferes with daily life – the shoulder no longer reaches the top shelf, the knee only bends to 90 degrees after surgery, the ankle no longer permits squatting – then increasing the range of motion is a sensible goal, and stretching is one route to it.

The decisive addition: "measured" means measured, not felt. "I'm inflexible" is not a restriction of movement. What decides is the comparison with the other side and with what the task requires – not a feeling of tightness.

9.2 Two applications with good data

Heel pain (plantar fasciitis). For persistent pain under the heel, a targeted stretch of the sole of the foot – sitting down, pulling the toes towards the shin and feeling the taut band under the foot – was tested against the usual calf stretch. The foot-specific stretch performed markedly better after eight weeks [37]. Here stretching is not only effective – the exact execution matters too. The revised 2023 guideline now recommends both stretches side by side, the foot-specific one and the calf stretch, for short- and long-term pain reduction. They do not stand alone there, however, but alongside load management, strengthening, orthoses and manual therapy [53].

The "frozen" shoulder (adhesive capsulitis). In this condition the joint capsule contracts and the shoulder loses mobility over months. The physiotherapy guideline explicitly recommends mobility and stretching exercises – matched to the stage of the condition: restrained while it is highly painful, more definite once the irritable phase settles [38]. Stretching vigorously in the painful early phase makes matters worse.

9.3 Nocturnal calf cramps

A small but pleasing finding: in a randomised trial with 80 people over 55, participants stretched their calves and hamstrings before going to bed for six weeks. The frequency and severity of nocturnal cramps fell markedly [39]. Cost: three minutes in the evening.

There is not much beyond this one trial, though, and a more recent study counsels restraint: in 98 people with frequent nocturnal cramps – mostly people living with liver disease – stretching was tested against meditation. Both eased the cramps, and to the same degree; there was no advantage for stretching, although participants clearly preferred it [54]. Whether it is the stretch itself that works, or the evening pause, is therefore open. Since it costs nothing and does no harm, it remains worth trying – but as an attempt, not as an established treatment.

9.4 When the sport demands it

Gymnastics, ballet, martial arts, hurdling, swimming, climbing – here flexibility is not an accessory but a performance requirement. Anyone who needs the splits, a high kick or a far-reaching shoulder position has to work on it deliberately, and static stretching or PNF are the most effective tools for that [8], [9].

One thing matters then: the range gained must also be controllable. Flexibility without strength in the new end position is the riskier variant – which is why every stretching programme in sport belongs together with strength training that reaches into the same angles.

10. When stretching does not help – and when it does harm

10.1 The "tense" neck

The feeling of tightness in the neck or between the shoulder blades after a long day at a desk is real. It is just that it is usually not a state of the muscle that could be pulled away – it is a sensation arising from sustained load in an unchanging posture. Stretching feels good against it for a few minutes; an hour later it is back.

The clearest result on this comes from Finland: 180 women with chronic neck pain, three groups, one year of follow-up. All three groups stretched. Only the two groups that additionally trained – with weights or with an elastic band – improved markedly in pain and disability [40]. Stretching alone was not enough.

That does not mean you should stop. It means that if you have been stretching for months and the neck stays as it is, what is missing is not more stretching but something else – strength, a change of load, breaks, sometimes sleep and stress. Movement during the day, incidentally, helps more reliably than a stretching session in the evening.

10.2 When everything is too mobile anyway

Some people are naturally extraordinarily flexible – elbows and knees that hyperextend, a thumb that reaches the forearm, palms that touch the floor effortlessly. This is called hypermobility. In itself it is not a disease: most very flexible people have neither unstable joints nor symptoms. Only when the two coincide is it classified, according to defined criteria, as a hypermobility spectrum disorder or an Ehlers–Danlos syndrome [42].

People who are hypermobile and troubled by it generally need not more range of movement but control: strength, muscle activation and stability in the end positions. That is where the physiotherapy recommendations put the emphasis – while noting at the same time that the evidence behind them is thin [55]. Stretching indiscriminately into already excessive end positions therefore usually reinforces what is bothering them – even, and especially, when something feels "tight".

This is not a blanket exclusion. Even a very flexible person can be genuinely restricted at one particular site – the shoulder after immobilisation, the ankle after a fracture. Then that movement is treated, and stretching may be part of it. What does not make sense is the whole-body stretching programme.

A simple test: if you move into the stretch position effortlessly and feel hardly any tension there, although you are going considerably further than others – then you do not need a stretching programme.

10.3 After a recent injury

A freshly strained or torn muscle is not stretched vigorously. The tissue is under repair, and pulling to the limit of pain is exactly what it does not need. Movement, by contrast, yes – careful, within the pain-free range, starting early.

There is no fixed embargo measured in weeks. How soon loading in longer muscle positions can resume depends on the injury, its severity and the course of healing, and the build-up is stepwise. What has no place in the early phase is vigorous static stretching to the end of range; graded loading in progressively longer muscle positions is a different thing and belongs to rehabilitation. Which step is due when is something to be discussed rather than guessed – more on this in our article on hamstring injuries.

The same applies after operations with sutured tissue: what may be stretched is specified by the operating clinic.

10.4 When it is not the muscle at all

A pulling sensation at the back of the thigh that travels into the calf or foot, feels electric or burning and increases when bending forward with a straight leg – that is often not muscle tension but an irritated nerve. The sciatic nerve runs exactly there, and the classic hamstring stretch tensions it too.

Stretching such an irritation vigorously makes it worse. You can recognise it by the fact that the pull travels further than the muscle reaches, that it feels different from familiar stretching, and that more of it does not make it better. That belongs in an examination, not in a stretch.

11. The "shortened" muscle – a misunderstanding with consequences

Hardly any explanation sits as firmly as this one: the back hurts because the hamstrings are short. The hip flexor is too short from all that sitting and tilts the pelvis. So: stretch.

Three objections, all factual:

• The muscle is usually not shorter. As shown in section 2.1, stretching changes sensation rather than length – and the same holds in the other direction: a muscle that feels "short" is rarely anatomically short. It is a muscle whose end position feels unpleasant.
• The link with the pain is weak. The major review of back pain in The Lancet records that the course of back pain is explained considerably less well by physical features such as flexibility or posture than long assumed – and that movement and exercise work without any particular form being superior [41].
• It distracts from what does work. Someone who spends years stretching against "shortened" muscles often does not do the thing that makes the difference in the studies: load regularly, get stronger, keep moving.

More on this in our article on back pain.

Lest a false impression arise: real restrictions of movement do exist, and they should be treated. The difference lies between a measured restriction that impedes a specific activity – and a feeling of tightness that is called upon to explain a pain.

12. How often, how long, how hard

If you have decided on a stretching programme, here are the figures from the literature.

• Total time: about five to ten minutes per week per muscle group. Five minutes is the threshold from which the gains become clear [10]; at around ten minutes per week they are maxed out and more adds nothing [49]. How you distribute that time is secondary.
• Individual stretch: 15 to 60 seconds, two to four repetitions per muscle group, on two to three days a week – the recommendation of the American College of Sports Medicine, which has held up to this day [12].
• Intensity: a clear, comfortably tolerable pull, no pain. For range of motion, painfully intense stretching adds nothing – in the large dose analysis intensity made no difference [49]. For tissue remodelling it does matter [5], but that is a goal for competitive sport, not for an ordinary stretching programme. If you hold your breath or grimace while stretching, you have gone too far.
• Timing: best on a warm muscle, so after training or after a warm-up. Immediately before a strength or jump effort, stay under sixty seconds [23].
• Distribution: how often you split the weekly time was not a discernible factor in the large analysis [49] – what counts is the sum. Several short sessions are nevertheless the more practical choice for most people, because they fit into the day more easily and therefore actually happen.

What is remarkable is what the official activity recommendations do not contain: the World Health Organization's 2020 guidelines name endurance, strength training and – for older people – balance training. Stretching does not appear as a recommendation of its own [13]. That is not a rejection but a ranking: for population health, other things count for more.

13. What else stretching does – an open chapter

In recent years an effect has come into view that has nothing to do with flexibility: the effect on blood vessels.

When a muscle is stretched, the vessels within it are stretched too. In animal experiments on aged rats, daily stretching over weeks led to better blood flow, more of the finest blood vessels and improved function of the vessel lining [46]. In humans, a twelve-week study using passive stretching likewise found better vascular function – and not only locally, but also at body sites that had not been stretched at all [45]. In a small randomised trial with forty people with high-normal blood pressure, an eight-week stretching programme lowered blood pressure more than brisk walking [47].

How should this be read? Interesting, but preliminary – and that is exactly how the 2025 consensus paper reads it too: stretching may promote vascular health, but more research is needed [52]. These are small studies, partly in animals, with measurements as the endpoint – not heart attacks or strokes. Nobody should put stretching in place of endurance training, whose benefit for heart and circulation has been established for decades; see our article on endurance training. But it does suggest that the effect of stretching may lie somewhere other than where it has been sought for decades.

14. Stretching in everyday life and in older age

Flexibility declines with the years – slowly, and more markedly in those joints that are rarely taken into their end positions: the shoulder overhead, the hip into extension, the ankle into a deep squat. Several things contribute to this: changes in connective tissue, joint capsules, muscles and the nervous system, along with conditions such as osteoarthritis – and the simple fact that large ranges of movement occur ever more rarely in daily life. The last of these is the only one readily in one's own hands.

It becomes practically relevant in a few concrete movements: the shoulder check while driving, the arm overhead to a shelf, the ankle when walking downstairs, hip extension while walking. If you notice one of these becoming harder, you have a good reason for a targeted programme.

Even here, though, stretching is rarely the first or only measure. Staying independent in older age calls above all for strength and balance – see our articles on muscle weakness in older age and fall prevention. Flexibility complements that usefully; it does not replace it.

One recommendation that costs little and preserves a lot: take every large joint through its full range of motion once a day. Arms overhead, trunk rotations, into a squat, hip extension. It takes two minutes, is not a stretching programme – and keeps a remarkable amount open.

15. Where, how often and for how long therapy takes place

A stretching programme is rarely the reason for physiotherapy – but it is often part of it. If it is, it comes with a measurement of the starting point: which angle is possible now, where does the movement end, and what does it end against – muscle, joint, nerve, pain? Only then can you say after four to six weeks whether anything has moved.

In Switzerland a medical prescription covers nine sessions [48]. Flexibility itself usually requires few of them: the exercises are quickly explained and the work happens at home. The larger part of the appointments generally goes into what is needed alongside – strength, motor control, building up load.

The decisive point is the same as everywhere: flexibility comes from repetition over weeks, not from the session. Five minutes on five days does more than half an hour in the clinic.

16. Eight common misunderstandings

"Stretching makes muscles longer."
Only partly, and only at high doses. Fascicles do lengthen when stretching is frequent and intense – with low volume, not at all [5], and stiffness stays unchanged in ordinary programmes [3], [4]. The larger share of the gain is tolerance of the end position [1], [6].

"Stretching prevents muscle soreness."
Twelve studies with more than 2500 participants: the difference is about one point on a scale of 0 to 100 [15]. Nobody notices that.

"If you don't stretch, you get injured more."
For the total number of injuries this is not true: in the largest prevention review, stretching showed no meaningful effect, while strength training cut the rate to below a third [18]. For certain muscle injuries the picture is less clear – a meta-analysis of four studies found fewer of them under stretching [50], which was promptly criticised as too thin a basis [51]. None of this changes the order of priorities.

"You must never stretch statically before sport."
This warning was once justified and is outdated in that severity. Under sixty seconds the loss is around one per cent [23], and after a complete warm-up with sport-specific drills it is no longer detectable at all [26].

"I have to stretch my tension away."
In the Finnish study of chronic neck pain, all three groups stretched; only those who additionally trained improved markedly [40]. The feeling of tightness is real – the treatment is a different one.

"Flexibility is always good."
Not for people who are already hypermobile and troubled by it. What they lack is control, not range of motion [55], and indiscriminate stretching reinforces the problem.

"The foam roller releases adhesions."
It increases range of motion, immediately [43] and over weeks [44]. It does not release connective tissue – neither the forces nor the time suffice for that.

"If you want to be flexible, you have to stretch."
Strength training through the full range of motion produces comparable gains [31], and so does eccentric training [32] – while supplying everything else at the same time.

17. When to get in touch

Seek medical assessment promptly:

• A joint loses mobility over weeks without an identifiable cause – the shoulder in particular.
• A pulling, burning or electric pain radiating into the leg or arm, with numbness, pins and needles or loss of strength.
• A joint can no longer be fully straightened or bent mechanically and locks.
• Pain, swelling and warmth of a joint without any identifiable injury.
• A sudden, sharp event in the muscle (like a whipcrack) with bruising or a palpable dent.

Raise it in physiotherapy:

• You have been stretching for months and nothing changes – neither the flexibility nor the symptoms.
• The stretching itself hurts, or you feel worse afterwards.
• A particular movement in daily life or at work no longer works – reaching a shelf, squatting down, the shoulder check.
• You are unusually flexible and yet constantly feel tight.
• You have a movement goal after surgery that has not yet been reached.
• You do a sport with high flexibility demands and are unsure how to build that up safely.

What to expect at our practice: first, clarifying whether there is a restriction of movement at all – measured, compared with the other side, and related to what you want to do. Then the question of what the movement ends against: muscle, joint capsule, nerve or pain. Those four answers lead to four different treatments, and only one of them is called stretching. From that comes a programme with clear target values and a home programme for the time in between. After four to six weeks we measure again. If nothing moves, we change the approach – or we recommend further assessment.

18. In summary

Stretching makes you more flexible. That is well established, and it takes less than most people think: five to ten minutes per week per muscle group – beyond that there is nothing more to be had.

Most of what else is attributed to stretching does not hold up. It does not prevent muscle soreness, it does not demonstrably lower the total number of sports injuries – whether it prevents individual muscle injuries is open and rests on very few studies – and for lasting restrictions of movement in the medical field it achieves less than two degrees. The muscle does lengthen somewhat – but only at high doses; at ordinary doses the larger share of the gain is forbearance towards the end position.

If you have little time, put it into strength training. It delivers comparable flexibility, markedly lowers the injury rate, and preserves muscle, bone and independence into the bargain. Stretching is the supplement, not the foundation.

And then there are the cases where it is exactly right: the measured loss of range after injury or surgery, the stiff shoulder in the appropriate phase, heel pain with the right exercise, nocturnal calf cramps, the sport that demands the splits. In those situations stretching is not a ritual but treatment.

The most useful question before any stretch is therefore not "how long?" but: what for? If a concrete answer comes back – an angle, a movement, a goal – then you are stretching for good reason. If the answer is "because that's what you do", the time is better invested elsewhere.

If you would like to experience what the muscles actually contribute when they are pre-tensioned: our learning game Federkraft lets you measure the difference between a jump from a squat and a jump with a countermovement – that elasticity is what stretching is really about.

References

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