Your warm up is meant to prepare you both mentally and physically for the activity that you are about to undertake. To enable it to do this it should contain a number of key elements. This is why your warmup should include these 3 things.
Raising of your heart rate. By doing this and increasing your blood flow to your muscles, you are increasing the temperature of muscles so they will react quicker. You are also upping the volume of oxygen and nutrients to your muscles, which they are going to need to work efficiently when you start training. Obviously the most important muscle is your heart. So it is just as important to preparing your heart gradually for an increase in activity. This avoids a rapid increase in blood pressure, which is not a good thing. Plus the exercise you undertake to increase your heart rate, primes your nerve-to-muscle pathways to be ready for exercise. This can improve coordination and reaction times, so the quality of your subsequent training is good.
Increases to the amount of synovial fluid in your joints. When you start low intensity exercise to warm up, your joints produce a liquid called synovial fluid. Synovial fluid kinda looks like egg whites. As your body warms up, the joints produce more of this fluid into the spaces between our jointed bones. This lubricates and protects your joints. This fluid protection basically becomes like “a combination of oil and a hydraulic shock absorber for your jointed bones. The lubrication side allows your joints to move easier, along with absorbing any sudden compressions of the joints. This then reduces the chance of soft tissue (ligament, tendon and muscle) injuries by allowing your muscles and joints to move through a greater range of motion easily and safely.
Dynamic stretching. If you spend all day sitting at a desk, hunched over a keyboard, or driving around commuting. You put very little stress on your muscles, this lack of movement can leave your muscles tight and constricted. Then if you hit the mats and immediately start sparring fast it can have serious consequences. If you think of your muscles like rubber bands if you do some short initial stretches you can get a lot more out them, than if you try to elongate them straight away. You can understand these bands will snap and the same could happen to your muscles. Baring in mind that muscle stiffness can be directly related to muscle injury your warm up should include dynamic stretching aimed at reducing muscle stiffness. Dynamic stretches are more appropriate to the warm up as they help reduce this muscle stiffness. Static stretching exercises do not reduce muscle stiffness and should really be used at the end of a class for warm down.
The one thing that can be forgotten is that your warm-up is not a workout. It is not meant to require an extensive recovery time. That’s why either specifically suitable exercises or variations of simple drilling at a suitable pace are good options to prepare you for the main class and ultimately sparring.
It can be tempting to up the intensity of the warm-up or skip it all together to get them, but both of these options can have an effect on the quality of your training. Including these 3 aspects into your warm up for bjj or any support activities you do, will help you get the most out of your training and reduce the potential for injuries.