Static Stretching: When It Helps, When It Hurts Performance and How Long to Hold

Six in the morning, gym floor, one person folded over a hamstring stretch with a timer running on the phone beside them. On the same phone, a clip with several million views insists that stretching before training “switches your muscles off.” The person holds the stretch anyway, counting to 90, because another clip said longer is better. Both can’t be right, and as of autumn 2025 the argument has spilled from physiology journals into group chats.

The spark is a genuine shift in the research. A decade of trials has quietly reversed the old locker-room advice, and a newer wave of small studies on very long daily holds has reopened a question most coaches thought was settled: can static stretching make you stronger, not just looser?

What follows is the state of the evidence, graded honestly, with the practical numbers people actually want: when to stretch, how long to hold, and when a tight muscle needs a clinician rather than a mat.

Why static stretching is back in the headlines

Fitness advice rarely trends because something new was discovered. It trends because two half-true messages collide. The first message, repeated in short-form video, is that static stretching before exercise makes you weaker and slower. The second, spreading from strength-training forums, is that marathon-length holds can grow muscle the way lifting does. Each has a thread of evidence behind it, and each has been stretched past what the data supports.

The first claim grew from laboratory studies in the early 2000s that measured jump height and sprint time after long, uninterrupted holds, often 90 seconds or more per muscle. The reductions were real, but the protocols looked nothing like how most people warm up. The second claim comes from a cluster of small trials published since 2022 in which volunteers held a calf stretch for an hour a day using a brace. Those participants did gain strength and muscle thickness, but the sample sizes were tiny and the time commitment is impractical for almost anyone.

Underneath the noise sits a steady body of mainstream guidance. Mayo Clinic, the NHS and Harvard Health all still recommend static stretching as a routine part of fitness, with a specific caveat about timing and hold length. The American College of Sports Medicine position, echoed in those sources, is that flexibility work belongs in a weekly program, that holds of roughly 10–30 seconds are enough for most adults, and that each muscle group benefits from about 60 seconds of accumulated stretch time per session.

So the headline question is not whether static stretching works. It does, for the specific job of improving range of motion. The sharper questions are when to do it, how long to hold, and what it cannot be expected to deliver.

Static stretching vs dynamic stretching: what is the difference?

Static stretching means moving a joint to the point where the muscle feels gently taut and then holding still, usually for 15 to 60 seconds. A seated hamstring reach, a standing quadriceps hold, a doorway chest stretch: all static. Dynamic stretching means moving a joint through its range repeatedly and under control, such as leg swings, walking lunges or arm circles, without pausing at the end point.

The distinction matters because the two approaches act on the body differently. A static hold temporarily reduces stiffness in the musculotendinous unit, the muscle and the tendon that anchors it to bone, and lowers the nervous system’s drive to that muscle for a short window afterward. That is why a long static hold can blunt a maximal jump taken immediately after it. A dynamic movement warms tissue, raises heart rate and rehearses the pattern you are about to perform, which is why it suits the minutes before sport.

Neither is “better” in the abstract. Cleveland Clinic’s physical therapists frame it as a matter of sequencing: dynamic movements before activity, static holds after or at a separate time. The NHS gives the same practical steer, suggesting that stretching after exercise, when muscles are warm, is the most comfortable and effective moment for holds.

A third category, proprioceptive neuromuscular facilitation or PNF, combines a static hold with a brief muscle contraction against resistance before relaxing deeper into the stretch. It can produce slightly larger short-term gains in range of motion, but it usually needs a partner or a strap and more instruction, so most guidance treats it as an option rather than a default.

If you remember one rule, make it this: static stretching changes how far a joint can move; dynamic stretching prepares the body to move well right now.

What changed recently

The clearest turning point came in 2016, when a systematic review by Behm and colleagues, indexed on PubMed, pooled more than 100 studies on the acute effects of stretching in healthy active people. Its conclusion reshaped warm-up advice: static stretches held for under 60 seconds per muscle produced only trivial changes in strength, power and speed, while holds longer than that carried a small but measurable cost. The review also found that static stretching improved range of motion and, in sports involving sprinting, might reduce muscle-tendon strain injuries. That nuanced picture replaced the blanket “never stretch before exercise” message that had circulated since the early 2000s.

Consumer guidance followed. Mayo Clinic’s current stretching page advises warming up for five to ten minutes before any static holds and keeping each hold around 30 seconds, up to 60 seconds for a problem area. Harvard Health’s flexibility guidance, updated in recent years, recommends holding for about 30 seconds and repeating, with daily stretching for people with limited mobility. The NHS continues to present post-exercise static stretching as standard practice.

The newer development, and the one driving search interest in 2025, is the long-duration stretching literature. Since 2022 a small research group in Germany has published several trials in which untrained volunteers stretched their calves for 60 minutes a day over six weeks and gained strength and muscle thickness comparable to a resistance-training comparison group. These are preliminary findings: small samples, one muscle group, extreme time commitments, and no evidence yet in trained athletes or other muscles. They are interesting rather than practice-changing.

No major body has changed its recommended hold times as a result. The practical advice in this article reflects the 2016 review and the current Mayo, Harvard and NHS guidance, not the preliminary long-hold studies.

What the evidence actually says about static stretching

Grading the evidence by outcome keeps the picture honest, because static stretching does some things very well and others barely at all.

Range of motion: strong evidence. Dozens of randomized trials show that regular static stretching increases joint range within four to six weeks. The mechanism in the short term is mostly sensory: the nervous system becomes more tolerant of the stretch sensation, so you can go further before it feels uncomfortable. Changes in muscle length itself take longer and are smaller. This is the one outcome where expert bodies and trials agree without hedging.

Immediate performance: moderate, consistent evidence of a small effect. Pooled trial data indicate that long holds reduce maximal strength and power by roughly 3–5 percent in the minutes afterward, while short holds under 60 seconds change performance by about 1 percent or less, an amount that disappears once a dynamic warm-up follows.

Injury prevention: weak to inconsistent evidence. Large trials in military recruits and runners have generally found no meaningful reduction in overall injury rates from pre-exercise stretching. Strength training, by contrast, has shown substantial injury reductions in meta-analyses. Some observational and sport-specific data suggest stretching may help with muscle strain injuries in explosive sports, but that remains a hypothesis rather than a settled fact.

Soreness: good evidence of almost no effect. A Cochrane review found that stretching before or after exercise reduced delayed-onset muscle soreness by about one point on a 100-point scale, a difference no one would notice.

Muscle growth and chronic strength: preliminary. The hour-a-day calf trials are intriguing but small and unreplicated across muscle groups.

In short: trust static stretching for flexibility, treat the warm-up penalty as real but small and avoidable, and do not rely on it to prevent injuries or soreness.

Does static stretching before a workout hurt performance?

It can, but the size of the effect depends almost entirely on how long you hold and what you do next.

Picture a sprinter who holds a hamstring stretch for two full minutes and then runs a timed 40 meters. Studies built on exactly that design found slower times and lower jump heights, typically a few percent. Now picture a recreational runner who holds each calf for 20 seconds, then jogs for five minutes and does a few leg swings before a steady run. In trials modeled on that pattern, the measurable penalty vanishes. The 2016 review that pooled these studies put the dividing line at about 60 seconds of total hold per muscle group.

Why does the effect exist at all? Two mechanisms are well described. A long hold reduces stiffness in the tendon and muscle, and a slightly slacker spring stores and releases less elastic energy, which matters for jumping and sprinting. A long hold also briefly dampens the nervous system’s output to the stretched muscle, lowering the force it can produce on demand. Both effects fade within minutes, faster still when followed by active movement.

For whom does this matter? Mainly people about to perform at or near their maximum: competitive athletes, powerlifters attempting a heavy single, sprinters at the line. For someone heading into a moderate jog, a yoga class or a circuit workout, a 3 percent change in peak power is irrelevant and probably undetectable.

The pragmatic sequence most sports medicine sources now suggest is simple. Warm up with light aerobic movement first. Use dynamic movements that mimic the activity. If a specific joint feels restricted and you want a static hold, keep it under 30 seconds and follow it with movement. Save the longer, flexibility-building holds for after training or for a separate session.

How long to hold a stretch: what the numbers show

The honest answer is shorter than most people assume. Research comparing hold durations has repeatedly found that 15 to 30 seconds produces about the same gain in range of motion as 60 seconds, provided the total time per muscle reaches around 60 seconds in a session. Four holds of 15 seconds and two holds of 30 seconds end up in the same place.

That is why the American College of Sports Medicine recommendation, reflected across Mayo Clinic and Harvard Health guidance, reads the way it does: hold each static stretch for 10–30 seconds, repeat two to four times, aim for about 60 seconds of accumulated stretch per muscle group, and do this at least two or three days a week. Daily stretching produces faster gains. Older adults may benefit from holding closer to 30–60 seconds, because tissues stiffen with age and stretch tolerance takes a little longer to shift.

Within the hold itself, intensity matters more than the clock. The target sensation is mild to moderate tension, the kind you could breathe through comfortably. Pain is not a sign of progress; it tends to trigger a protective tightening reflex that works against you. Bouncing at the end of the range, sometimes called ballistic stretching, is the one approach mainstream sources advise most people to avoid, because it loads the muscle suddenly at its most vulnerable length.

How long until it works? Measurable changes in flexibility typically appear after three to four weeks of consistent practice, with continued gains over two to three months. Stop stretching and the gains fade over a similar timescale, which is less a flaw than a reminder that flexibility is a maintained property, like cardiovascular fitness.

A full-body routine covering calves, hamstrings, hip flexors, quadriceps, chest and shoulders fits comfortably inside ten minutes.

Static stretching at a glance: holds, timing and goals

The table below condenses the practical numbers from the trial literature and current mainstream guidance. Treat it as a starting point, and adjust with a clinician if you have an injury or a medical condition that affects joints or connective tissue.

Goal	Best timing	Hold length	Sets and frequency	Evidence strength
Improve flexibility or range of motion	After exercise or as a separate session when muscles are warm	15–30 seconds (30–60 for older adults)	2–4 holds per muscle, totaling about 60 seconds; 2–3 days a week minimum, daily is better	Strong (many randomized trials)
Warm up for sport or heavy lifting	After light aerobic activity; dynamic movement preferred	Under 30 seconds if used at all	1–2 brief holds on a restricted joint, followed by dynamic drills	Moderate (short holds show trivial performance change)
Protect peak strength, speed or jump height	Avoid long static holds in the 15 minutes before performance	Keep total under 60 seconds per muscle	Not applicable	Moderate (consistent small decrement with long holds)
Reduce next-day soreness	Any	Any	Any	Good evidence of near-zero effect
Prevent overall injury	Any	Any	Any	Weak or inconsistent; strength training has better support
Build muscle or strength through stretching alone	Daily, very long sessions	Up to 60 minutes per muscle	Daily for six or more weeks	Preliminary (small trials, one muscle group, untrained participants)

Two patterns stand out. First, the outcomes with the strongest support are the modest ones: more range, no performance penalty if holds stay short. Second, the most dramatic claims circulating online, whether about injury-proofing or stretching your way to bigger muscles, sit at the weak or preliminary end of the scale. That is not a reason to dismiss them, only a reason to hold them lightly until larger trials arrive.

Does stretching prevent injury?

This is the claim most people were raised on, and it is the one the evidence supports least. The largest randomized trials, including studies of thousands of military recruits who stretched before training versus those who did not, found no meaningful difference in overall injury rates. Trials in recreational runners reached the same conclusion. A 2014 meta-analysis in the British Journal of Sports Medicine compared injury-prevention strategies and found that stretching had no significant protective effect, while strength training roughly halved sports injuries and reduced overuse injuries by close to half.

Why would a looser muscle not be a safer one? Most sports injuries do not happen because a muscle was asked to go beyond its range. They happen through fatigue, sudden loads, poor landing mechanics, contact, or tissue that has not adapted to a training spike. Flexibility addresses none of those directly. A joint with more range but no additional strength at the end of that range may even be harder to control.

There is a narrower exception worth stating accurately. The 2016 systematic review on PubMed noted that in sports built around sprinting and explosive changes of direction, static stretching might reduce muscle-tendon strain injuries such as hamstring pulls. The supporting data are mostly observational or from small trials, so this counts as plausible rather than proven. If you play a sport with a high strain-injury rate, a warm-up that includes some stretching alongside dynamic work is reasonable, provided holds stay short.

The practical message is not that stretching is pointless for injury. It is that stretching should sit beside, not replace, the strategies with stronger evidence: progressive strength training, gradual increases in training load, adequate sleep and recovery, and sport-specific movement practice. A flexible ankle on a weak calf is not protection.

When static stretching clearly helps

Set aside the performance debate and a quieter story emerges: static stretching is one of the few interventions with reliable evidence for restoring and maintaining movement range, and that matters more as the decades pass.

Tissues stiffen with age. Collagen cross-links accumulate, tendons lose some elasticity, and inactivity compounds both. The result shows up as a shortened stride, difficulty reaching overhead, or a hip that no longer extends fully, which shifts load to the lower back. Harvard Health’s flexibility guidance frames daily stretching for older adults as a way to protect the ability to do ordinary tasks, from tying shoes to turning to check a blind spot. Trials in adults over 65 consistently show improved joint range with regular static stretching, and some show modest improvements in walking speed and balance, though the balance evidence is mixed.

Desk work is the younger adult’s version of the same problem. Hours of sitting keep the hip flexors shortened and the chest muscles drawn forward. Static holds for the hip flexors and pectorals, combined with strengthening of the opposing muscles, are a standard part of what physical therapists prescribe for posture-related discomfort. The evidence here is more observational and clinical than trial-based, but it is consistent with the strong range-of-motion data.

Rehabilitation is the third clear use. After an injury or surgery, regaining lost range is often the first goal, and controlled static stretching under a clinician’s guidance is central to that process. Specific conditions with good evidence for stretching as part of management include plantar fasciitis, where calf and plantar fascia stretches are a first-line recommendation across mainstream sources, and adhesive capsulitis of the shoulder.

Many people also simply feel better after stretching. That subjective calm is real, likely tied to slow breathing and parasympathetic activation, and it is a perfectly good reason to keep doing it.

Does static stretching after exercise reduce soreness?

Delayed-onset muscle soreness, the stiffness that peaks one to two days after unfamiliar or hard exercise, is caused by microscopic damage to muscle fibers and the inflammation that follows, not by lactic acid and not by muscles that “tightened up.” Because the cause lives inside the fiber, it was never likely that pulling on the muscle afterward would fix it, and the trials bear this out.

A Cochrane systematic review, the most rigorous type of evidence synthesis, pooled randomized trials of stretching before, after, or both before and after exercise. The average reduction in soreness was about one point on a 100-point scale, a figure the authors described as too small to be noticeable. Later trials have not overturned that finding.

Does this mean a post-workout stretch is wasted time? Not at all, but the reason to do it is different from the reason people give. Muscles are warm after exercise, which makes static holds more comfortable and may make range-of-motion gains slightly easier to achieve. The NHS explicitly recommends stretching after a workout for this reason. The few minutes of slow breathing also act as a cooldown, easing the transition from exertion to rest.

What does help with soreness? Evidence is modest for most recovery tools, but light active movement over the following day or two, adequate protein and sleep, and a gradual rather than sudden increase in training intensity all have more support than stretching. Soreness itself is self-limiting and usually fades within three to five days.

If the soreness is severe, one-sided, accompanied by swelling, or if urine turns dark after an intense session, that is no longer ordinary DOMS and warrants prompt medical attention, which the final section covers in detail.

Can long static stretching build muscle or strength?

This is the question driving the newest wave of interest, and it deserves a careful answer rather than a dismissive one.

The idea has roots in animal research from the 1970s onward, where muscles held in a stretched position for days grew substantially. For decades the human evidence was thin because nobody could reasonably replicate those durations. That changed when a group of German researchers began publishing trials in 2022 and 2023 in which volunteers wore a calf-stretching orthosis for 60 minutes a day, six days a week, for six weeks. Participants gained maximal calf strength, increased muscle thickness measured by ultrasound, and improved ankle range, with gains comparable to a group doing conventional calf raises. A follow-up trial using ten-minute daily holds found smaller but still measurable effects.

What should a reader make of this? Several cautions apply. The participants were untrained, the muscle studied was the calf, and sample sizes were small. Untrained people respond to almost any novel stimulus. Whether the same would happen in a quadriceps or in a person who already lifts weights is unknown, and the time cost of an hour a day per muscle makes the approach impractical as a general training method. No mainstream guideline body has incorporated these findings, and none is likely to until larger, independent replications appear.

What the studies do suggest is that the dividing line between stretching and strengthening is blurrier than textbooks implied. Mechanical tension, the primary signal for muscle growth, can be delivered by a sustained stretch as well as by a contraction. That has possible relevance for people who cannot load a muscle normally, such as those recovering from certain injuries, and researchers are exploring it.

For now, grade it as promising, preliminary and not a substitute for resistance training.

Common myths about static stretching

Viral fitness content thrives on absolutes. Here are the claims circulating most widely, each measured against what the trials show.

“Static stretching before exercise makes you weaker.” Partly true, mostly overstated. Holds beyond about 60 seconds per muscle reduce peak strength and power by a few percent for a short window. Holds under 30 seconds followed by a dynamic warm-up produce no meaningful change. The claim applies to athletes chasing a personal best, not to most people walking into a gym.

“Stretching prevents injuries.” Not supported by the largest trials. Overall injury rates are unchanged by pre-exercise stretching. Strength training and sensible load progression have far better evidence.

“Stretching stops you getting sore.” Cochrane evidence shows a reduction too small to notice. Warm muscles make post-exercise stretching comfortable, but it does not spare you tomorrow’s stiffness.

“You have to hold for at least a minute.” Trials comparing durations show that 15–30 second holds, repeated to reach about 60 seconds total per muscle, match longer holds for flexibility gains.

“If it doesn’t hurt, it isn’t working.” The reverse. Pain triggers protective muscle guarding and raises injury risk. Mild to moderate tension is the evidence-based target.

“Stretching lengthens your muscles.” In the first weeks, gains in range come mainly from increased tolerance to the stretch sensation. Structural changes in muscle and tendon are smaller and take months.

“Stretching builds muscle like lifting.” Early trials with hour-long daily calf holds in untrained people are intriguing, but the evidence is preliminary and impractical to apply. Resistance training remains the proven route.

“Dynamic stretching has replaced static stretching.” They serve different jobs. Dynamic movement prepares you for activity; static holds build range over time. Most well-designed programs use both, at different moments.

How to do static stretching safely, and who should be cautious

Technique is simple, which is one reason people skip the details that matter.

Warm the tissue first. Five to ten minutes of easy walking, cycling or the first part of a workout raises muscle temperature and makes the stretch more comfortable. Move into the position slowly until you feel mild to moderate tension, then stop. Breathe steadily; holding your breath raises blood pressure and tends to tighten everything. Keep the hold still, with no bouncing. Release slowly and repeat two to four times. Work both sides, even if only one feels tight, and favor the muscles that your day shortens: calves, hamstrings, hip flexors, chest and the front of the shoulders for most desk-bound adults.

A few groups should adapt the approach or check with a clinician first.

• Joint hypermobility, meaning joints that already move beyond the usual range, often needs strengthening more than stretching; aggressive stretching can increase instability.
• Recent injury or surgery: follow the rehabilitation plan rather than a general routine, since timing and range limits are specific to the healing tissue.
• Osteoporosis: avoid forceful forward bending of the spine, which concentrates load on vertebrae that are more fracture-prone.
• Pregnancy: hormonal changes loosen ligaments, so gentle holds within a comfortable range are preferred over pushing for new flexibility.
• Inflammatory arthritis or acute joint flare: stretching an inflamed joint can worsen pain; wait for the flare to settle and ask about safe range.
• Nerve symptoms: a stretch that produces tingling, numbness or electric sensations is loading a nerve, not a muscle, and should be stopped.

None of these is a reason to abandon flexibility work. They are reasons to tailor it, ideally with a physical therapist or physician who knows your history, rather than copying a routine built for someone else.

When to see a doctor

Most tightness responds to time, movement and a consistent routine. Some symptoms that people try to stretch away are signals of something a clinician should assess. Seek medical advice if you notice any of the following.

• Sharp, sudden pain during a stretch, especially with a popping sensation, swelling or bruising, which can indicate a muscle or tendon tear.
• Numbness, tingling, weakness or shooting pain into an arm or leg, which points to nerve involvement rather than muscle tightness.
• A joint that locks, gives way or cannot be fully straightened or bent, suggesting a structural problem such as a cartilage or ligament injury.
• Calf pain with swelling, warmth or redness, particularly after travel, surgery or prolonged inactivity, which needs urgent assessment to exclude a blood clot.
• Severe muscle pain with dark or cola-colored urine after intense exercise, a possible sign of muscle breakdown that requires emergency care.
• Back pain with new bladder or bowel changes, numbness around the groin, or weakness in both legs, which is a medical emergency.
• Chest pain, breathlessness or dizziness during stretching or exercise.
• Tightness that is persistent, one-sided and worsening over weeks despite regular stretching, or stiffness that is worst in the morning and lasts more than an hour, which can be a feature of inflammatory conditions.
• Pain that persists beyond 48–72 hours after a session or interferes with sleep.

Children and adolescents with persistent tightness, limping or pain around the heel, knee or hip should also be assessed, since growth-related conditions can mimic simple muscle tightness.

If you have a heart condition, uncontrolled blood pressure, a connective tissue disorder or are recovering from surgery, discuss any new flexibility routine with your physician or physical therapist first. They can set safe ranges and advise on timing relative to any treatment you are receiving. Decisions about managing an injury or an underlying condition belong with the clinician who knows your history; a general article can inform that conversation but never replace it.

Frequently asked questions

Is static stretching before a workout bad?

Not for most people. Short holds of under 30 seconds, done after a light aerobic warm-up and followed by dynamic movements, produce no meaningful loss of performance. The small decrement seen in studies comes from holds longer than about 60 seconds immediately before maximal sprinting, jumping or lifting. If you compete at a high level, save long holds for after training.

How long should you hold a static stretch?

Hold each stretch for 15–30 seconds at mild to moderate tension, repeat two to four times, and aim for about 60 seconds of total stretch time per muscle group. Older adults may benefit from holds closer to 30–60 seconds. Trials show this matches longer single holds for flexibility gains while keeping any effect on strength negligible.

What is the difference between static stretching and dynamic stretching?

Static stretching holds a muscle still at the point of gentle tension; dynamic stretching moves a joint through its range repeatedly without pausing, as in leg swings or walking lunges. Static holds build range of motion over weeks and suit the post-exercise period. Dynamic movements warm tissue and rehearse the activity, which makes them the better choice immediately before sport.

Does stretching prevent injury?

The largest randomized trials found that pre-exercise stretching does not reduce overall injury rates. Strength training and gradual increases in training load have much stronger evidence. There is a plausible but unproven signal that stretching may reduce muscle strain injuries in sprint-based sports. Treat stretching as one part of a program rather than as injury insurance.

Does static stretching reduce muscle soreness?

Barely. A Cochrane review of randomized trials found that stretching before or after exercise reduced delayed-onset muscle soreness by about one point on a 100-point scale, a difference too small to feel. Stretching after a workout is still worthwhile because warm muscles make flexibility work comfortable, but it will not spare you tomorrow’s stiffness.

Can static stretching build muscle?

Possibly, but the evidence is preliminary. Small trials since 2022 found that untrained adults who stretched their calves for 60 minutes a day over six weeks gained strength and muscle thickness similar to a calf-raise group. The samples were tiny, only one muscle was studied, and the time cost is impractical. Resistance training remains the proven method.

How many days a week should you do static stretching?

At least two to three days a week produces gains; daily stretching produces them faster. The American College of Sports Medicine guidance reflected by Mayo Clinic and Harvard Health suggests most adults can cover the major muscle groups in about ten minutes per session. Consistency matters more than session length, and gains fade over weeks if you stop.

Should static stretching hurt?

No. The target is mild to moderate tension that you can breathe through comfortably. Pain triggers a protective tightening reflex that works against the stretch and raises the risk of a strain. Stop immediately if you feel sharp pain, tingling or numbness, since those sensations suggest a nerve or tissue is being loaded rather than a muscle lengthening.

Is it better to stretch before or after exercise?

After, for static holds. Muscles are warm, the stretch is more comfortable, and there is no risk of blunting performance. Before exercise, a light aerobic warm-up followed by dynamic movements prepares the body better. If a joint feels restricted before activity, a brief hold under 30 seconds is fine as long as you move dynamically afterward.

Who should avoid static stretching or be careful with it?

People with joint hypermobility, recent injury or surgery, osteoporosis, an active inflammatory arthritis flare, or symptoms such as numbness and tingling should adapt their routine and check with a physician or physical therapist first. Pregnancy loosens ligaments, so gentle holds within a comfortable range are preferred. None of these rules out flexibility work; they call for a tailored plan.

References

• NHS: How to stretch after exercising
• MedlinePlus: Exercise and Physical Fitness

This article is for general information only and is not a substitute for professional medical advice. Please consult a qualified doctor about your individual situation.