To stretch or not to stretch?

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Before a workout, that is.

Research done over recent years has been hard on some traditional sports practices, with some approaches that have been ingrained in sports for many years now coming under close scrutiny. One such approach is the use of a 'warm up' prior to sport. As therapists and trainers, we hear many gym-goers, runners, and sports players guiltily confess, “I never warm up!” but the question is, do they need to and why?

Warming up prior to physical performance is believed to facilitate mental and physical readiness, prevent injuries, and improve performance. Static stretching – once strictly adhered to has since been thought to impair performance and have no impact on injury prevention. As such, static stretching has been replaced with dynamic stretching. But is it wise to cease static stretching altogether?

The body of research behind stretching is contradictory and often confusing. Let us first explore the different types of stretching before we talk about how and when to stretch.
 

WHAT ARE THE DIFFERENT TYPES OF STRETCHING?  

Static stretching involves holding a position near the end range of comfort for a prolonged period of time, feeling a stretch sensation in the muscle.  For example, this is what a static hamstring stretch could look like:

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Dynamic stretching involves moving a limb and muscle from one end of its range to the other in a slow and controlled manner. For example, a dynamic stretch for hamstrings would involve swinging the leg forwards and backwards: 

  Photo credit: Yuri Elkaim

Photo credit: Yuri Elkaim

PNF stretching (proprioceptive neuromuscular facilitation) incorporates static stretching and isometric muscle contractions to increase range of motion. For example – during a lying down hamstring stretch, a partner’s hand or shoulder is used to push against for a few seconds, to contract the hamstring muscle. The muscle is then relaxed and the stretch pushed to their new limit of range of motion. This is usually repeated 3-4 times:

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WHY DO WE STRETCH AS PART OF A WARM-UP?

There are four main proposed benefits to stretching prior to sport or exercise:

1. Improved performance

Despite the high number of studies done on this subject, it is still difficult to say whether stretching helps performance. Some evidence shows that static stretching can briefly inhibit a muscle’s ability to generate power – this generally occurs when the stretch is held for longer than 60 seconds immediately before performance. However, in studies where stretches were held for less than 20 seconds 10 minutes before performance, it has been found that static stretching had no impact on performance. Some studies show that dynamic stretching can slightly improve performance when done immediately prior to the exercise. The negative effects of stretching before sport such as reduced power and speed shown in some research realistically will not be noticed by most of us and is only of importance to elite athletes at the top of their game. It also very much depends on what the sport is. For something like gymnastics or martial arts, the importance of stretching beforehand is perhaps more significant than for sprinters or weightlifters where speed and power is key.

2. Increased flexibility

It has been established that PNF, static and dynamic stretching can improve range of motion over a short duration. Over time, stretching enhances flexibility not by actually lengthening the muscle but by increasing the brain and body’s tolerance to that stretch by calming down the nervous system. It is proposed that by using a few stretches, whether static or dynamic, as part of a warm-up may cause short-term neural adaptations thereby resulting in an improved stretch tolerance. Again, the usefulness of this outcome depends on what you are about to do – is it an activity that requires deep, end range positions and full range of movement?

3. Injury Prevention

It is often thought that stretching prior to exercise can reduce the likelihood of getting injured however the evidence for this is pretty weak and inconclusive. Some evidence suggests that static stretching has no overall effect on complex or overuse injuries but there may be a benefit in reducing acute muscle injuries, especially with repetitive contractions such as with sprinting.

4. Reduction of delayed onset muscle soreness (DOMS) 

DOMS is muscle soreness that occurs between 24 and 48 hours after exercise and it usually occurs when someone is new to a particular exercise or has not performed it at a certain intensity previously. The effect of DOMS is often worse when the exercise involves eccentric muscle contraction (when a muscle contracts while lengthening or during the lowering phase of an exercise). While there is certainly no harm in stretching before or after exercise in relation to DOMS, it appears that there is little benefit to it with most studies showing very little or no difference in DOMs when stretching or not stretching. Any benefits may be most relevant for athletes who participate in high intensity exercise daily, and therefore need to recover quickly.

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The evidence does not seem too strong in favour of stretching as part of a warm-up. What should we do instead to prepare for exercise?

Generally prior to going in to the ‘main body’ of your training session or sport the goal is to prepare the body by raising body temperature, heart rate, respiration rate and blood flow. This could be achieved through spending a few minutes on an exercise bike, doing a few ‘laps around the field’ or it could be achieved through sports-specific dynamic range of motion exercises that are relevant to the sport. Static stretching is likely to cool the body down and while being generally specific to a muscle it is not often specific to the requirements of your sport. So if you can achieve the flexibility requirements for your sport through dynamic stretching, why not trade in static stretches for higher intensity drills that are specific to your sport. For those who do use stretches regularly before a sport or activity, there may be positive psychological benefits of a familiar routine and positive expectations in which case it will not be harmful to continue.

With no ‘one size fits all’ approach to warming up prior to exercise and some fairly wishy-washy evidence behind it, the most sensible thing to do is whatever feels right for your body in order to prepare it for whatever it is about to do. We cannot generalise that either static or dynamic stretches are more effective prior to performance, but instead must analyse the requirements of the specific sport as well as the individual. Including mobility work into a warm-up is a sensible idea, moving the body in ways that will help it in the exercise you are about to do. For example, if you are about to work on your squats in the gym, use a dynamic hip opener to get the hip joints moving before adding load. If you are about to run then doing some dynamic leg swings will help the legs prepare for the motion of hip flexion and extension. It’s about waking up the nervous system too, as well as the joints and soft tissues. Neuromuscular activation exercises are useful to help recruit those important muscles that you’ll be using in your session. For example, runners are often advised to do some crab walks, gluteal bridges or some single leg stability work to get their gluteal muscles firing; this will then help with their running technique and efficiency.

Here is a brief summary of a general approach to a warm-up that is adaptable to different sports and training environments:

1. HEART RATE RAISER 
Get blood pumping, increase HR, blow flow and respiratory rate. Encourages physical and mental readiness.

2. DYNAMIC MOBILITY
Move joints and soft tissues to prepare for the movement/training you are about to do. Calm down nervous system to cope with ‘end range’ or deeper positions if needed.

3. ACTIVATION
Wake up muscles needed to enhance technique and improve performance in the sport.

4. SPORT SPECIFIC DRILLS
Full physical and mental readiness, high intensity for optimal preparation.

As such, follow the recommendations, apply them to your sport but most importantly, listen to your body do what feels right for you!


ABOUT THE AUTHOR

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Lucy Warren is a Physiotherapist and Pilates specialist from the UK. She has a first-class honours degree in Physiotherapy from Cardiff University, and is also an APPI-trained matwork instructor. Lucy has extensive sports experience with professional and semi-professional teams and athletes, having provided pitch-side physiotherapy for multiple elite sport teams in the UK. She has also worked for the British Army for two years, assessing and treating infantry soldiers and helping them to rehabilitate to peak fitness. 

Lucy taught matwork Pilates for several years before making the transition across to Reformer Pilates. Lucy loves using the Reformer and other Pilates equipment with her clients in order to achieve their specific rehabilitation goals. She believes that it is an incredibly versatile tool which can lead to daily life improvements like better posture and more efficient movement, as well as relief from pain associated with physical imbalances.

In her own time Lucy is a keen netballer, skier, and loves to travel to new places.