 Hey what's up everyone, welcome to another video, my name is Dylan and I'm a cycling coach at CTS and today we're going to be talking about a topic that a lot of you guys have asked me about and that's stretching. In this video we're going to be answering three important questions. Will stretching before exercise improve your performance? Will stretching after exercise improve your recovery? And will stretching in general help with injury prevention? The answers to these questions might surprise you. This is one of those cases where my preconceived notions on a topic were completely shattered when I actually took a look at the research. At the end of the video we'll also touch on stretching to improve your cycling position and alleviate back pain so be sure to stick around for that. If you're new to this channel I make weekly training, racing and gear related videos going over tips and tricks that I've learned in my 12 years of training and racing experience that have gotten me to the top of the ultra endurance mountain bike game in the US and as a cycling coach at CTS. If you want to learn how to get faster or just more about the science of training in general then be sure to subscribe and if you have a training question or a topic you'd like to see me cover in a future video then be sure to leave it down in the comments section below. I do my best to get to all the questions in the comments. All right without further ado let's jump straight into the science. The first question we're going to answer is will stretching before exercise improve your performance? This study on stretching's effects on cycling efficiency had subjects perform tests at 85% of VO2 max until exhaustion with and without pre-exercise stretching. The results showed that stretching before the test actually decreased the time to exhaustion. They concluded that a preceding stretching routine significantly decreased exercise efficiency and time to exhaustion during heavy intensity. So what exactly is the reason for these somewhat surprising results? Isn't stretching supposed to be good for exercise? The study explains that stretching changes the viscoelastic properties of the muscle tendon unit by decreasing its stiffness and that a relatively stiffer muscle tendon unit reportedly has a greater capacity for force production owing to improved force velocity and length tension relationships and to a better initial transmission force. Basically a stiffer muscle can produce more force and stretching decreases the stiffness of a muscle thereby decreasing the amount of force it can produce. And it isn't just one study showing these kinds of results. It's pretty unanimous across the scientific literature that stretching before exercise decreases your performance. This study on the effect of static stretching on endurance running performance had subjects perform a 60-minute treadmill run with and without stretching beforehand. They found that the distance the subjects covered decreased after stretching and that stretching increased the energy expenditure of the run. So these runners were using more energy to run slower after they stretched. That's exactly what you don't want as an endurance athlete. As always though you want to look at the balance of evidence which is exactly what this 2012 meta-analysis did. Looking at 104 studies they concluded that results clearly show that static stretching before exercise has significant and practically relevant negative acute effects on maximal muscle strength and explosive muscular performance. And these findings are universal regardless of the subject's age, gender or training status. An important thing to note here is that these studies are looking at static stretching or stretching where you're not moving. But what about dynamic stretching? This study on the effect of dynamic stretching on running performance had subjects perform a 60-minute running test with and without dynamic stretching beforehand. They found no difference in the distance covered between the two conditions however the energy cost of running was still higher after dynamic stretching. So dynamic stretching probably isn't helping you in your race or workout but it certainly isn't hindering your performance like static stretching is. This flies in the face of what many people believe about stretching. I specifically remember gym teachers and coaches telling me that I needed to stretch before I worked out. This is ridiculous man. Stretching has really helped me on the bike. Oh interesting how's that? Oh yeah well uh you know I just feel better I guess? It's probably not too surprising that stretching does an increase in performance but surely it improves recovery and helps with injury prevention right? Well let's tackle improved recovery first. This study on whether post-exercise stretching relieved soreness had subjects perform a 20-minute step test to induce soreness. Subjects were then randomly assigned into one of three groups. One that didn't stretch at all, one that stretched only the left leg, and one that stretched both legs. They found no difference in soreness between the stretching and non-stretching groups. One, two, or three days after exercise leading to the conclusion that stretching did not alleviate exercise-induced muscle soreness either acutely or chronically. Stretching is often cited as an effective recovery method but when actually put to the test it doesn't seem to hold up. And again this isn't just one isolated study. If you look across the scientific literature the results seem to be pretty consistent. A systematic review looking at stretching's effects on soreness from exercise found that stretching before or after exercise does not confer protection from muscle soreness. This review came to the same conclusion stating the studies produced very consistent findings. They showed there was little or no effect of stretching on the muscle soreness experienced the week after physical activity. One study on the effect of stretching on repeated sprint performance actually found that static stretching of the lower limbs during recovery periods between efforts may compromise repeated sprint ability. Despite popular belief the evidence that stretching will improve your recovery and reduce your soreness is severely lacking. But again this isn't the only reason why people stretch and perhaps one of the most important reasons why people stretch is for injury prevention. Does this claim hold up to the science though? A study on stretching for the prevention of lower limb injuries took 1500 army recruits and split them into a stretching group and a control group. The stretching group performed static stretching exercises in their warm-up during 12 weeks of training while the control group did not. The results showed no significant difference in the prevalence of injuries between the two groups. These results were very surprising to me. I thought that for sure stretching would help with injury prevention and again I didn't just look at one study here. The balance of evidence across all the studies done on stretching for injury prevention confirmed these findings. Multiple reviews all come to the same conclusion. Stretching does not affect the incidence of injuries. Now there is some evidence to suggest that stretching may help in the prevention of musculotendinous injuries but the results are far from conclusive. This review on the efficacy of stretching for the prevention of injury stated that results seem to indicate that there is moderate to strong evidence that routine application of static stretching will not reduce overall injury rates on the basis of the work that has been undertaken. Secondary findings indicate however that there is preliminary evidence that static stretching may have a positive effect on preventing musculotendinous injuries. So this is relevant when we're talking about sports like gymnastics or football where the incidence of tearing a muscle are more common. Obviously crashing is always a concern while riding a bike but for overuse injuries associated with cycling it doesn't seem like stretching will help at all. Recovery and injury prevention aside many cyclists perform regular stretching routines for a different reason. Stretching will undoubtedly increase your flexibility and being more flexible means you can get into a more aggressive aerodynamic position right? There is very limited research on this but this study on the effect of time trial position on physiological and aerodynamic variables found that the flexibility of the cyclist does not limit the participant to cycle with a small torso angle. This was because in the population tested the flexibility required for the time trial position was already within the range of motion of their participants. It's important to note here that the data on this is extremely limited and more work needs to be done on how flexibility affects your ability to produce power in aggressive cycling positions. This study on hamstring extensibility in road and mountain bikers found that compared with mountain bikers and non-cyclists road cyclists have significantly greater hamstring muscle extensibility. Does this mean that road cyclists need to be more flexible in order to get into more aerodynamic positions? No, this is a classic case of correlation does an equal causation. It would definitely be interesting to see more science come out on this particular topic. It's also interesting to note that this study on the aero position found that as in previous literature no correlation was found between low back pain and cyclists and low back inflexibility. So what can we conclude from all this? Well first of all stretching before a race or a workout will likely decrease the amount of power you can produce so you want to generally avoid it. When you see somebody doing a quick stretch on the starting line of a race, yeah that's not helping them. Stretching after your workout has not been shown to improve recovery and stretching in general has not been shown to be effective at injury prevention either. Finally the data on whether or not flexibility is beneficial for riding in an aggressive aerodynamic position is severely lacking. As I said at the beginning of the video I was not expecting these results and I had no intention of discrediting the effectiveness of stretching until I looked at the science. This is why you have to look at the research. It turns out your gym teacher was wrong just because something seems true or somebody told you it doesn't make it so. Dude this guy at the bike shop told me to hold my breath while I'm climbing to simulate high altitude training. That makes sense right? My advice when it comes to stretching is this. If you enjoy stretching do it. If you don't enjoy stretching then don't do it. As long as you're not stretching right before you ride it'll probably have very little effect on your cycling. Now I already know that a lot of you are going to ask about yoga and whether or not it's effective for cycling. It's important to note that none of these studies looked at the effects of yoga and I know that the supposed benefits of yoga go beyond just stretching. Let me know down in the comments if you'd like to see a whole video just on yoga. Thanks for watching. I hope you guys found this information helpful. If you like this video be sure to give it a like, share with a friend, and subscribe so you don't miss any training tips. If you want to be notified every time I put out a video be sure to hit the notification bell as well. If you're looking for a coach if you sign up for CTS be sure to use my code CTS DJ to save $40 by waiving the registration fee. Details are down in the description.