In my earlier post I had briefly explained that there are three energy systems at work in the body and the currency of energy in the body is ATP. In this post, we will explore this further in order to understand the importance of warm up before a training session.
The body needs ATP to fuel the muscles to do the work. Work may require short burst of energy (say jumping up once) or medium burst of energy such as climbing a flight of stairs. Some times work may involve sustained feed of energy like when you are running a marathon.
The first energy system that provides short burst of energy is called the ATP-PC system. This system can provide burst of energy for slightly more than 10 seconds. The first part of the ten seconds is supplied ATP that was already available in the body. This depletes the Phosphate from the ATP. In order to continue supplying ATP for the rest of the 10 seconds, the body uses the available Phospocreatine (PC) to supply Phosphate recreate ATP and continue fueling the 10 second burst of intense energy. The reason we have a 10 second threshold for this energy system is due to the limited free ATP and PC available in the body at the start of the activity. Once the 10 seconds is over, another energy system has to take over and continue supplying energy to continue the activity.
That system is the Glycolytic system. This energy system can power activity until another 50 seconds. The carbohydrates that you eat is converted into Glycogen and stored in the muscles. The Glycolytic system consists of converting the Glycogen into ATP. Not only does this process take a little longer to produce ATP, but also it creates almost half the amount of energy that the ATP system provides. However, the Glycolytic system allows longer supply of energy (upto 50 seconds). The main problem is that the byproduct of this system is lactic acid in the muscle cells recruited. This causes muscle fatigue. Therefore for longer work, energy has to come from the third energy system which is the Oxidative system.
The Oxidative system provides energy at 1/3 the rate of the Glycolytic system but does not produce Lactic acid. Fats stored in the body is used in this system for the most part but as it takes a longer chain or reaction in the body to break down fats (lipolysis), Carbohydrates are used intermittently to sustain ATP creation. If the activity continues and carbohydrates are exhausted, the body will have to depend on fats and energy production becomes slower and at this stage Protein may be used as a last resort source to produce ATP. The objective in any work out would be to avoid getting to this stage.
As you can see, the three energy systems supply varying amounts of energy for varying amount of time. While you work out, you need all the three energy systems working for you. This is the reason why your trainer would insist that you perform a proper warm up before you commence weight training.
Warm up can be performed on machines such as a treadmill, elliptical or rowing machine. You could also get warmed up by doing light free hand exercises without equipment or running (or on the spot jogging) at a slow pace for 15 to 20 minutes. When a warm up is completed, all the energy systems in the body are up and running. The muscles are warmed up, the heart rate is elevated and the body is geared up to work. A warm up session significantly reduces potential injury during the work out.
Always warm up before starting a training session. Check out my next post tomorrow about the types of muscles in your body and how they impact which sport or athletics you are best suited for.