What makes you stop cycling during a high rep workout? Why do your legs and lungs burn during a sprint?
The answer lies in how your body utilizes and metabolizes oxygen. Just like your physical inspiration and exhalation through the lungs, the cells within your body breath and replensh themselves in the same way. When you stress your organs and muscles during an intense bout of exercise, the cells within your body increase their respiration rate just as you do. But not only do they 'breathe' but they also consume a large amount of glucose in order to produce ATP (energy).
Just as you consume and then dump excess, the cells consume oxygen and 'dump' hydrogen ions thus making the amount of Hydrogen in your blood and muscles rise as you preform more work. When your acidic levels rise (too much hydrogen) it is said that your pH rises (precent hydrogen). What you feel when this happens is a burning or soreness inside your muscles that can last for mere moments or sometimes days!
So how do you, CrossFitter, delay the onset of that acidosis and go harder longer?
Well it is done in two ways.
1) Build your VO2 max through aerobic training.
2) Frequently test your Latate Threshold.
In our gym, the types of workouts vary greatly. Some days you are doing a 7 minute workout and others it can be 20. In the 20 minute range you are training your aerobic (with oxygen) capacity and coupled with the different exercises we get to train your body to not hit its 'threshold' but to continue for long durations without stopping.
The Latate Threshold training is when we go balls to the wall on a sled drag or a 'Fran' type workout. This training helps raise our cells capacity to efficently utilize oxygen under duress. By constantly testing this, we burn many calories and teach our body how to sustain a greater workload at a faster pace (we become more FIT)!.
So feel the burn and love the struggle. You body is learning how to adapt every day to whatever is thrown at it. If you are picking and choosing your workouts, then there is probably something you are running from and it will show in your varied perfromance. Come often and give all you have to each Workout, you will develop into the Elite Athlete you want to be.. I promise.