What Are the Benefits of Warming Up?
When we’re trying to juggle training with everything else in our lives, it can often feel like we have to squeeze as much out of the time we have. As a result, it’s easy to forgo a proper warm up. Some of you might not even do a warm up anyway, regardless of time. Firstly, let’s address the name; “warm up”. It’s a little misleading, it’s got very little to do with increasing temperature, since this will happen anyway through increased blood flow from exercise, or extra layering if you’re training in colder conditions. If we think of this pre-exercise ritual as “Movement Preparation”, we are simply preparing the body for the training and intensity it is about to undergo. Three areas in particular we want to address, in varying degrees depending on the type of training we are about to do, are; joint function, muscle activation and blood flow.
Your movement preparation might change depending on what it is you’re about to do, for example; before a run our attention might be more hip, knee and ankle joint focused. Whereas, with a swim it will be more about the shoulders and rotation ability.
Correct joint function is important when we’re exercising to ensure we are working efficiently. Poor movement limits out range, which will hamper our performance and can cause faulty joint loading, which may increase your risk of injury. Mobility work; foam rolling, dynamic flexibility work will help you move better. Back this up with some drill, or muscle activation work and you should feel an immediate improvement in how you move.
If we focus on blood flow to the working muscles and how this is affected when we start to exercise we can have a better understanding of the importance of some kind of preparation work before we train and especially race. Our circulatory system supplies our muscles with oxygenated blood, sending it to where it’s needed. But we only have a certain amount of blood in our bodies, and it’s important we maintain a good pressure within this system to function properly. The flow of blood to the muscles is controlled by the speed at which the heart beats and changes in the size of our blood vessels.
At rest our heart rate is lower, so to sustain blood pressure our blood vessels contract, which is ok because the oxygen demand at rest is minimal. When we start to exercise, we need more oxygen, so the vessels within that muscle dilate to accept more blood and the heart beats faster to maintain good pressure and increase the blood supply. The more muscles that are active, the more vessels open and so the heart must work harder to maintain the pressure in the system and meet the demand from all the muscles.
There is another clever way our bodies circulate blood and that’s with muscle contraction. As muscles contract and relax they create a pumping effect that helps return blood back to the heart. This also helps remove waste product from muscles during exercise. (Think when you’ve had a blood test, and once the strap is on your arm, if you clench your fist can you see your veins enlarge). The harder muscles work, the more it helps pump blood back to the heart. This is also why isometric/static exercises lead to that ‘burning’ feeling in the muscle, because while it’s working, it’s not actually moving so therefore waste product is building up.
When we start exercising there’s a slight delay from the time we start moving to our heart rate getting up to the speed it needs to be to supply us with the oxygen we need as well as our blood vessels opening up to allow increased blood flow to the muscle. During this time we incur an oxygen deficit. Until we’ve paid off this deficit it will be difficult to increase our work rate without feeling an increased rate of perceived exertion. You can often feel this in the real world if you compare how hard you can work if you go from an aerobic work rate into a harder long climb on the bike; you can work at a fairly high HR before feeling you’re at max. But if you go from a resting HR straight into the same climb, you’ll feel like it’s a lot harder before your HR gets anywhere near where it was before. This is a worthy consideration for when you do interval training, should you completely rest between intervals, or should you keep moving but at a light intensity to keep to HR from dropping too much.
During a race
In a race situation you want to start working at your race pace as soon as you can, but because of the delay in bloody supply you’ll lose some time getting up to this work rate. However, if you can be on that start line with your blood vessels already dilated and heart rate elevated, then you’ll be able to get up to that target pace more quickly. It’s common for people racing triathlon to report feeling tired very quickly after only a few hundred metres of racing, because of this oxygen deficit. There’s a good reason this might be more apparent in swimming that other sports. Because we’re typically standing and walking around before a race start, our legs are already working, albeit very slightly, but our arms are doing very little. Combine this with the compressive element of the wetsuit and our blood vessels in our upper body are very constricted.
Preparation for a swim start
To prepare yourself optimally for a swim start, you need to more than just get your heart rate up. You need to increase the circulation to your swimming muscles and the best way to do this is to swim. Aim to be in the water as soon as you’re allowed to before your start time so you have time to get your muscles working. Start slowly, think about technique and focus on slow controlled breathing and especially your exhalation. Then try adding in a few harder efforts, bursts in speed to increase your heart rate. Do this a few times but try to gauge how much time you have before you start as you want to leave yourself time to position yourself where you want to be on the start line and let your breathing rate come down a little. Once you start you should find it a lot easier to get back up to your working pace.
What about the other end of our training, what happens to our blood flow when we stop exercising?
If you stop exercising from a high intensity to a completely static state, suddenly you lose that muscle pumping effect. As a result, the pressure in the circulatory system drops. This means the heart has to suddenly increase to maintain to blood flow to the muscles. We see this in athletes that finish a race and continue to breath very heavily for some time afterwards. To help maintain pressure, our blood vessels contract too. This may lead to blood pooling within the muscle and waste product being removed more slowly. Anyone who’s ever finished a race and sat down immediately with know what this feels like when you try to move again a little later. While the body will recover from this in a matter of hours on its own, it can still lead to light headedness and discomfort at the time. This is why we see athletes warming down after training. Keeping the muscles moving, keeps the pressure and blood flow to the muscles that have just been working, so you can bring the effort down slowly. You can incorporate this into your own training session; warming down at the end of a turbo or WATTbike session, or factoring the last few lengths of a swim, or km of a run to be done more easily.