Should you stretch before a workout?

Stretching is an interesting topic, and depending on who you ask, you’ll probably get different answers when it is applied pre-workout. On one side there is the argument that static stretching is the worst thing to do because it can potentially reduce performance. But on the other hand, you don’t want to go into a workout totally cold.

This is an age-old debate within the industry, and thankfully there has been a fair amount of research in the field. First of all, it’s important to understand the different types of flexibility that you can do:

1. Static stretching – this is when you hold a position without moving for a set period of time and is a passive (without tension) form of stretching. 
2. Active stretches – which uses the shortening of a muscle on one side of a joint to move the other side. Think about when you have your arm out and bring your fingertips to your shoulder, the contracting bicep on the top stretches the tricep on the underside of the arm. 
3. Kinetic stretches – these are similar to active stretches but are more complex movements where you take a specific joint through its full range of motion and kinetic stretches are done slowly so create a lot of tension. These are things like Controlled Articular Rotations (CAR’s).
4. Dynamic stretches – movement-based stretches that are not held. This could be lunging before doing leg exercises or push-ups before doing a chest workout.

So let’s see what the science says – most of the research to date is on static and dynamic forms of stretching, which is great because these are the more typical types of stretches performed.

Research into static stretching

These studies looked at performance measures when doing static stretching directly before different types of training. One study by Nelson et al (2008) found that performing 30 seconds of static stretching 5-10mins prior to sprint training decreased sprint times. A study by Junior et al (2017) found a significant reduction in reps performed in strength training after static stretching. And a study by Fowles et al (2000) found a 13% decline in strength (in the ankle/calf) when stretching was done 15 minutes before testing and a 14% reduction in muscle stiffness (it’s worth noting stiffness in a muscle creates better stretch reflex so less stiffness actually impairs muscle performance).

Research into dynamic stretching 

A study by Yamaguchi et al (2005) found an increase in leg extension power when doing dynamic stretching (but a slight decrease of power after static stretching). And a landmark study by Fletcher et al (2004) tested static and dynamic stretching on 20m sprint time and found that dynamic stretching improved performance. However, what is important to know is that when static stretching was followed by dynamic stretching there was a slight increase in sprint performance from baseline (note that dynamic stretching alone produced the best performance).

So what does this all mean for your warm-up?

As we see from the studies, static stretching alone appears to decrease performance when done before training. So there is a strong argument to avoid static stretching prior to exercise. What I will say is that most of the stretches done in the research were held for 30-60 seconds and the reality is most people don’t stretch that long or with real intensity.

Dynamic stretching seems to improve performance and this is potentially due to increased muscle temperature and because dynamic stretching is more specific to the types of movements we perform when training. 

The question of which dynamic stretches you should perform is a harder one to answer because it’s really going to depend on the type of exercise you are about to undertake. But it’s fair to say you want to keep the movements similar to what exercises you will be doing in the session.

It’s not all doom and gloom for static stretching.

In all the studies that tested range of motion pre and post, these measurements improved by static stretching, which shouldn’t come as a big surprise. Static stretching does improve the range of motion at a joint. Remember that when static stretching and dynamic stretching were done together, performance was still slightly improved. This is really important because if you know you lack movement at a joint and you need to use that joint in training – such as ankles when performing squatting or shoulders when doing chin-ups – then you can do static stretching followed by a dynamic stretch to mitigate any negative effects on performance that the static stretching alone may cause. 

This is how I programme mobility for my clients; only perform static stretches on areas that are needed and follow them up with a dynamic move on the same area. If a client’s range of motion is adequate then I like to keep static stretching away from workouts and create a morning/evening routine using static stretches or do them as a stand-alone session. 

What I will say is that it is important to make sure the range of motion you are seeking to open out is actually required. Some common areas like hamstrings often feel tight but are pretty much always weak, just because something feels tight doesn’t always mean it needs stretching, this is where having an assessment can really help you streamline the way you warm up. 

But what about injury prevention and reducing soreness?

You might have read this and thought, “well I don’t care about a slight reduction in performance, I just don’t want to get injured or to be sore”. Surprisingly, there is no clear evidence that stretching before or after exercise has any effect on delayed onset muscle soreness Herbert & Gabriel (2002). Blood flow is the most important thing for reducing soreness, so I tell my clients to do a cooldown or simply go for a walk later that day as this is usually more beneficial. 

A systematic review by Behm et al 2016 tried to find if there was a clear relationship between stretching and injury prevention and found no direct correlation. 

However, it is almost impossible to study this accurately and make a definitive case either way about stretching and injuries. Injuries are complex and things like previous sports, posture, lifestyle etc need to be considered. I would generally suggest that dynamic stretching is going to be your best bet for injury prevention simply because they more closely replicate the movements you will be performing in your session, increasing the temperature of the muscle and often incorporating the stretch reflex. 

What I recommend you do

Static stretching before exercise does reduce performance, to mitigate this, pair them with dynamic stretches on the same area. Don’t just stretch everything for the sake of it. Make sure the joint in question actually requires more range. 

There is no clear evidence to suggest static stretching will reduce injury risk or soreness. Use dynamic stretching before working out and factor in time for a cool down to keep the blood flowing before you sit down for the day. If you enjoy static stretching, try getting into the routine of doing static stretches in the morning and/or evening, just not near your workout. 

When you do static stretching try to hold the stretch for long enough to make some sort of change, 60 seconds is a good time to aim for. When selecting your dynamic stretches think about what movements your body will be going through in the workout, if you’re going to be running, try doing walking lunges or heel rockers, if you’re doing squats try this hip flow series.