Does stretching actually work? Does stretching prevent injuries? Does stretching lengthen muscles?
This blog will try to tackle the tough question; does stretching actually work? In addition we will discuss if stretching can reduce injuries in sports and physical activity and if it actually lengthens muscles. Stretching works for certain people in certain conditions but not for everyone and not in every case. Stretching may help to prevent injuries in very specific instances. Stretching, in most cases, does not actually lengthen muscles.
Now that we have provided you with some brief answers let’s delve into this topic a bit further and explain the research in the area of stretching. Both Zach and I are very interested in this topic which is why we decided to collaborate on this blog. Admittedly, I have been a very infrequent stretcher and I would describe myself as always being “tight” in most major muscle groups. I am writing this blog to help people decide if stretching is useful but also to understand for myself if I should be stretching consistently or if it is a waste of time.
In this blog when we discuss stretching we are referring to holding a position for a number of seconds from 10 to 300 seconds. There are various forms of stretching but we are referring to the type of stretching that most people think of when they stretch their thigh muscles, quadriceps or hamstrings, or calf muscles, gastrocnemius, by holding a static position.
Can stretching prevent injuries?
Maybe! As many of the articles that we reviewed point out it is very hard to make a direct association between an intervention, in this case stretching, and exercise or sport related injuries.[1] There are a lot of things that happen while playing sports and when injuries happen in sports there are many factors that lead to the injury. Here are a list of some factors that can contribute to sports injuries: the weather, the playing surface, the type of shoes, the skill level of other players, the rules of the sport, the individual's mental state, the individual's endurance and strength, and the individual's skill level among many other factors. Trying to make a direct correlation or association between stretching and injury prevention is very challenging. A 2008 systematic review concluded that static stretching did not reduce the overall incidence of exercise related injuries when they were used as a warm-up prior to activity.[2] In this same article three high quality studies did show a reduction in muscle, tendon and ligament injuries after static stretching.[2] This review evaluated a total of seven studies of which three were controlled clinical trials and four were randomized clinical trials.[2] Because the evidence was not strong the authors of this study suggest that static stretching “may reduce musculotendinous injuries.”[2]
Does stretching improve sport performance and resistance or weight training?
Unlikely. In most of the reviewed studies there is evidence to suggest that stretching immediately before playing a sport or starting weight or resistance training can reduce your overall performance. When stretching was done immediately before weight or resistance training there was an overall reduction in strength.[3] Strength was reduced by stretching immediately before resistance training and therefore is not recommended prior to resistance training especially if stretching for long periods of time in this case more than 8 weeks.[3] Stretching immediately before sports does not improve sprinting and jumping performance. There were some weak associations made in the research that point to some benefit of static stretching but these benefits were not significant enough to recommend static stretching to enhance sprinting or jumping.[4] A systematic review in 2024 concluded that more research is needed because the current studies differ greatly making comparisons challenging.[4] To date there are not enough studies or a strong enough level of research evidence to justified static stretching as a way to improve jumping and sprinting performance in sports.[4] Other research studies have also stated that stretching actually reduces your overall jumping and sprinting performance and therefore is not recommended prior to a sport.[5] Another important thing to remember is that there are sports such as jogging, running, swimming and cycling where the rates of muscle and tendon injuries are low and stretching is usually not required before starting.[1] Stretching in these sports does not decrease or increase injury risk but it may reduce performance.[1] One research study found that having a warm up and cool down for jogging did not reduce the overall injury risk and there is not enough research to show that stretching can help to prevent leg injuries for people who jog.[1]
What should I do before playing sports or lifting weights?
Static stretching for a long period of time is not recommended based on the research reviewed above. However, dynamic movements that are similar to the sport are recommended.[5,6] Dynamic movements actually improves jump height and distance and sprinting, whereas static stretching, particularly if it is done for a long period of time, can reduce overall jumping and sprinting performance.[5,6] Dynamic movements should look and feel like the sport or activity you are about to play.[5,6] For example, if you were to do dynamic movements before a basketball game you should take some jump shots, layups, dribble a ball, run, jump, pivot and change directions at or close to game speed before you start to play. You should take your whole body through movements that are similar to the sport you are about to play. If you are about to lift weights then the simplest dynamic movements would be to do the same motion you are about to do with lower weights. For example, a dynamic movement for a biceps curl if your highest planned lift is 30 lbs is a biceps curl with a lower weight and then increasing the weight gradually until you lift your maximum planned weight. For resistance training using the same movement with a lower weight will prepare your body for the heavier weights.
Are there any benefits to stretching?
Yes! There are benefits to stretching and the most important one to consider is the possible reduction in musculotendinous injuries.[2] As I mentioned above there is some preliminary evidence from three high quality studies that shows that static stretching may reduce musculotendinous injuries.[2] This means that injuries that occur in sports that are related to muscles, tendons, and ligaments may be reduced with static stretching.[2] Please keep in mind that this study was not suggesting stretching immediately prior to playing sports. In relation to sports and injuries, less flexible people are more likely to incur overuse injuries, whereas people who are very flexible are more likely to get acute injuries while playing.[2] Keep this in mind for yourself and think about how it applies to your body and playing sports. Another benefit to consider is that static stretching for long durations, between 120-300 seconds, reduced muscle stiffness.[7] If reducing muscle stiffness is important to you then long duration stretching, between 2-5 minutes per stretch, can help reduce your stiffness.[7]
When should I stretch?
Likely after sports or resistance or weight training. Since there is a fair amount of evidence presented above that suggests that static stretching can reduce your overall strength, jumping and sprinting abilities it is not ideal to stretch prior to playing sports or lifting weights.[4,5] Static stretching can be completed at the end of sport participation or at the end of lifting weights or at another time when optimal strength and running or jumping are not required. For example, if you have just finished playing soccer or lifting weights you can stretch immediately afterwards to receive some of the benefits of stretching. The research suggests that you should stretch for between 120-300 seconds which is between 2 to 5 minutes, 3-4 times per week for at least 8 weeks to see any benefits.[3,7] These longer durations of stretching have some research support but more studies are required to determine optimal duration and volume of stretching. One interesting thing that most of the stretching research points out is that the recommended time, between 2-5 minutes, and the recommended duration, 3-4 times per week and for at least 8 weeks, is much longer than what is often prescribed by physical therapists like myself.[7] Also the researched duration and frequency of stretching is much longer than most people choose or continue to engage in stretching.
Am I making my muscles longer if I stretch? What is actually happening to my body when I stretch?
No! Your muscles are unlikely to actually get longer in most cases. The most likely thing that is happening when you stretch is that you are improving your tolerance to stretching.[8] When you stretch you feel some discomfort and therefore you do not push too far and also prevent injuring yourself. As you continue to stretch your body adapts and gets more used to the feeling of stretching and allows you to go further into a position of stretch. As you stretch over time you will notice that your movement in that area of your body, also called range of motion, increases, this is because your tolerance for stretching has improved and not because muscles are longer.[5,8] Other reasons for increased range of motion are due to less stiffness in the muscle tendon unit, a change in the viscoelasticity of the muscle and tendon unit, and a change in reflex activity.[8] When you stretch you stimulate a reflex that resists the stretch but with longer durations of stretching you suppress this reflex and this allows you to go through more range of motion because you have inhibited this reflex.[8] Now I would like to present some contradictory research that has some limitations. In a recent systematic review which included 19 studies the authors conclude that static stretching can increase muscle fascicle length.[9] A muscle fascicle is made of a number of muscle fibers or muscle cells and a number of muscle fascicles make up a whole muscle.[10] In this review study it was noted that only high stretching volumes caused longitudinal fascicle growth.[9] High stretching volume was defined as stretching for between 30 to 300 seconds, on average 101 seconds, and between 4.4 to 16.8 weeks.[9] Some muscle changes were reported at six weeks but most muscle fascicle changes took more than six weeks.[9]
There were several limitations of this study that I will list below:
- The average age of the participants was between 19.5-22.7 years old
- 73% of the participants were male
- There were 467 participants in this study
- All stretching was for the lower leg and mostly the gastrocnemius or calf muscle
- Only one study included an athletic population
- The intensity of the stretch was defined qualitatively as being painful or comfortable making it very hard to reproduce
Based on this systematic review, with a small number of people tested, there is the possibility that long duration stretching can cause some physiological changes to the muscle fascicle for young healthy males.[9]
If I have had an injury or surgery should I stretch?
Yes! If you have had an injury or surgery and you need to safely regain your movement, stretching is essential to restoring your normal range of motion. Most of the research about stretching does not apply to you immediately after injury and surgery. When you injure an area of your body you will likely lose range of motion due to pain, swelling and damage to structures around the joint.
Let’s take the example of a knee injury, specifically an ACL injury. If you have torn your ACL, which is one of the four ligaments in your knee, you will experience pain, swelling and a loss of knee range of motion. In the initial phase of healing you should not force your knee range of motion by stretching but once your knee has settled down it is critical to regain your knee range of motion. During your early recovery, even with knee swelling and pain, it is usually necessary to start bending and straightening your knee. If you do not do this you risk losing function and movement around your knee. It is important to consult with a health care provider before you start working on your knee range of motion to ensure you are safe to do so. After an ACL injury the typical rules of stretching do not apply. In most cases after an ACL injury, daily and possibly three times per day, knee range of motion exercises are required to improve knee bending and straightening. If you were to have an ACL injury and you were to decide stretching is not necessary you will delay your healing and compromise your recovery.
Let’s consider another scenario where a person has had a knee replacement. Again the standard rules of stretching do not apply because early knee range of motion by doing knee straightening and bending exercises is critical to recovery. With a knee replacement or ACL surgery it will be necessary to do knee straightening for up to five minutes three times per day and knee bending for 20-25 repetitions three times per day. Regaining knee range of motion early is critical to a successful recovery. It is likely you will spend more time on range of motion and stretching than what is recommended for young healthy people without any injury or surgery. To learn about some typical knee range of motion goals after an ACL surgery go to this link. To learn about some typical knee range of motion goals after a knee replacement go to this link.
If I have knee osteoarthritis should I be stretching?
Yes! One area where stretching has been studied and shown to reduce overall pain is in the area of knee osteoarthritis. Knee osteoarthritis is a progressive wear and tear of the knee joint that can result in pain, limitations in motion, reduced strength of the muscles around the knee and functional limitations of daily life activities. Research on stretching for people with knee osteoarthritis does show that it reduces a person's pain.[11] In this review article stretching was more effective at reducing pain for people with osteoarthritis when compared to a control group who did not stretch.[11] It does seem reasonable to include stretching as part of the rehabilitation for people who have knee osteoarthritis.[11] The limitation of this review article is that most studies include stretching with an overall program to manage osteoarthritis so it is not always possible to separate out stretching from strengthening and other interventions for managing knee osteoarthritis.[11]
For joint contractures, arthrofibrosis and neurological issues does stretching help?
Unlikely. This topic is beyond the scope of this blog but the brief research review that was done in this area suggests that stretching is ineffective for joint contractures, arthrofibrosis and for most neurological conditions such as stroke, multiple sclerosis, and parkinson's.[5,12] Joint contractures are when a joint does not move past a certain position and is “stuck” due to injury or surgery. Arthrofibrosis is an abnormal formation of tissue around a joint that prevents it from bending or straightening through the normal range of motion. There is some evidence that a range of motion mechanical device may help to improve range of motion in the case of arthrofibrosis.[13] The primary author of this blog has piloted an at-home and in-clinic method of producing sustained knee flexion and extension that he has found to be clinically useful with his patients.[14] The method used to improve knee bending and straightening are outlined in this clinical suggestion article. The primary author of this blog has seen improved knee extension and flexion utilizing the method described in this article but there are no large studies utilizing this method that we are aware of.
Neurological conditions cause stiffness and tightness that is mediated by the central nervous system and therefore are not altered by stretching.[5,12] If you have any of the conditions mentioned above please speak to a health care provider to determine if stretching is appropriate for you.
Practical suggestions based on the stretching research
- Stretch one muscle group, for example your quadriceps, for 120 seconds or two minutes, four times per week for at least eight weeks.
- Stretch at a time separate from resistance or weight training and not immediately before playing a sport.
- Prioritize areas where you feel tight and muscle groups that are used primarily in your sport or physical activity. You do not need to stretch every muscle group.
- Prior to jogging, swimming and cycling you do not need to stretch. An appropriate warm-up would be to start with walking, then walk faster and then start jogging.
- Prior to sports you should do at least 10 minutes of dynamic movements that look and feel like the movements of the sport you are about to play. It is important to take your body through the movements that you may go through while playing the sport.
- After sports and after resistance or weight training may be a good time to stretch.
- For injuries and surgeries the rules of stretching change and you will likely need to do very regular range of motion exercises, up to three times per day, until you regain your full range of motion. In these cases you should seek out the advice of a health care provider to ensure that you are engaging in the appropriate amount of range of motion exercises. Within our app, Curovate, you will receive your daily physical therapy exercises following a knee replacement, ACL injury or surgery, hip replacement, knee osteoarthritis, or for knee and hip strengthening. Find our app at the Apple and Android links below.
- If you have joint contractures, arthrofibrosis or a neurological condition you should seek the advice of a health care provider to determine if stretching can provide any benefit.
Conclusion
This blog helps to answer many of the common questions related to stretching and I have summarized the answers below. You can read the details of each section in the blog above.
Can stretching prevent injuries?
Maybe!
Does stretching improve sport performance and resistance training?
Unlikely.
What should I do before playing sports or lifting weights?
Dynamic movements.
Are there any benefits to stretching?
Yes.
When should I stretch?
Likely after sports or resistance or weight training.
Am I making my muscles longer if I stretch?
No!
If I have an injury or surgery do I need to stretch?
Yes but you should seek out the advice of a health care provider to determine the appropriate time and amount of stretching.
If I have knee osteoarthritis should I be stretching?
Yes!
For joint contractures, arthrofibrosis and neurological issues does stretching help?
Unlikely.
What are some practical suggestions I can follow for stretching?
Go to the section above called "Practical suggestion based on stretching research" and follow the 8 simple suggestions.
If you have had an injury, surgery or need some daily stretching and strengthening try the Curovate physical therapy app. Curovate provides rehabilitation for people before or after a knee replacement, knee osteoarthritis, ACL injury, ACL surgery, hip replacement, or for knee and hip strengthening to prevent injuries. Curovate provided daily video-guided exercises, progress tracking and the ability to measure knee and hip range of motion.
If you need further customized assistance during your surgery or injury recovery check out our Virtual Physical Therapy page to book your 1-on-1 video session with a physical therapist.
Blogs related to range of motion and the Curovate app
- How does measuring my knee range of motion at home compare to a physical therapist measuring my knee?
- How to measure knee range of motion in the Curovate app
- What if the Curovate exercises are too hard for me?
- What if the Curovate exercises are too easy for me?
- How Can I Improve My Knee Bending and Straightening | Curovate
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