Well, ok, so considering where all the exciting research and information is coming from in the world of bodywork nowadays, I suppose that F really should be for Fascia. There are ridiculously large amounts of stuff out there written about it, and I am also one of those that have been talking about it. However, you can read all about that in my Fascianating Fascia post from a while ago. Yes, there is more to say about it, and yes there is more to know, however, muscle fatigue, and more importantly WHY muscles fatigue seems to be something that confuses the people I come across.
There are a number of different reasons why muscles can fatigue and stop working, hence making you as an athlete unable to continue your training or racing, or whatever. This is not meant to be an exhaustive list, but should give you some insight into the physiological reasons why you aren’t going as fast as you thought you could.
Reason 1: Energy pathways. The most obvious one really. You have 3 different energy pathways, as one gives out the next picks up, but each pathway creates energy at a slightly slower rate. Creatine Phosphate stored in your muscles provides lots of energy for a few seconds, the Lactic system creates a little less, for about 1 minute, if that. Then the aerobic system kicks in, burning carbohydrate, and once that gives out you’re down to burning fat, which, again is slower. (this is all very simplistic, but basically as you move into each subsequent energy system, you get slower).
Reason 2: “Lactic” acid. Working at a certain intensity makes your muscles burn. This is because as you burn carbohydrate it creates a metabolic waste product. This is removed by breathing. If you work so hard that the waste product isn’t being expelled from the muscles fast enough, theoretically the slightly more acidic solution that is created in the muscles by the waste product (“lactic acid”) takes the muscles into a slightly higher pH level and makes them less efficient. And you feel knackered.
Reason 3: Lack of calcium. Muscles rely on calcium (among other things). When a nerve impulse reaches the muscle, the sarcoplasmic retinaculum is flooded with calcium, which initiates the process of the contraction. If there is deficient calcium, the muscle contraction literally cannot take place.
Reason 4: Damaged muscle fibres. This is pretty self-explanatory. If a muscle fibre has been damaged by an impact, or by overuse it is going to work less efficiently. Imagine trying to drive a car with a damaged engine. There you go. You don’t want to do that.
Reason 5: Lack of recovery. I suppose this is something that encompasses all of these things. If you go out and train, train, train, you are constantly putting muscles under stress and breaking them down. If they are not given enough time to heal and recover, they never actually get to be as strong as they could be. As Graeme Obree says, “Training is bad for the body, but Training + Recovery makes a better athlete“. (ok, that may have been paraphrased, but you know what I mean.