Muscles type II
Type II muscles are used for speed and strength movement.
For the subject at hand, it is important to note that type II muscles have very few mitochondria, and this makes them very poor fat burners.
However, it doesn’t mean strength and speed exercises need to be ruled out of your fat loss strategy.
Type II muscles get energy from glucose, and almost exclusively use anaerobic glycolisis for energy. This requires no oxygen, which is why you can lift heavy weights while holding your breath, like most power lifters do. This will turn you bright red, because the rest of your body does need oxygen as it runs partly on aerobic energy processing.
Anaerobic glycolisis may not be a good fat burner, but it is an excellent calorie burner. This is because it is energetically poorly efficient. This means that it will require a lot more calories to work.
So speed and strength movements bjurn very little fat (unlike slow, enduring movements, especially when the Pasteur effect has kicked in), but it burns a lot of calories in the form of glucose.
So how do you use speed and strength for fat loss?
White muscle cells store the energy that will be used for such exercises in the form of glycogen. When it runs out, it gets more sugar out of the bloodstream to rebuild its supply for the next round of speed/strength effort, but it can take days to restore that supply entirely. This is why after 5 reps you are burned out for the day and need to either move on to the next muscle group or call it a day.
By restoring glycogen supply, your white muscles use sugar that will no longer be available for the red muscles, as well as just about every cell in your body. They will therefore need to use fat that they can process in their mitochondria.
So while white muscle cells will not burn fat directly, they will cause all the other cells to do so… given there is an overall calorie deficit. This calorie deficit is easier to obtain using speed and strength because of the inefficient nature of anaerobic glycolisis.
But there are a few important points you need to be aware of. If you are too predominantly strength/speed profiled (too few red muscle cells), you have a lot less mitochondria that can burn fat. This means you will have to accept slow fat loss to avoid ketosis (very uncomfortable and unsafe).
In this case you will especially need medical supervision, and it may be required that you leave your comfort zone sooner to build some red muscle cells through endurance activity, despite the fact that that kind of exercise is very uncomfortable for you.
If that is the case, take things slowly. Rely on your strength abilities to some extent, but force yourself to build up your endurance. Naturally, if you start with very little, just walking will be great. Also consider swimming. Don’t try to go too quickly, and whatever you do, avoid ketosis.