All right, so during recovery, what happens? So I'm going to draw from several studies to discuss the recovery process. As you have seen, creatine phosphate stores are rapidly activated during short, intense exercise. In the first six seconds phosphocreatine accounts for around 50% of the total ATP energy used by the muscle. And studies using maximal running show that the phosphocreatine's stores become almost completely depleted after the first ten seconds. However, phosphocreatine is quickly resynthesized during recovery. And this line here shows the time course for the phosphocreatine energy system to be resynthesized. And here is the muscle pH recovery from the 30 second bout. And we are interested in recovery at 1.5. Minutes. And at 3 minutes. And then at 6 minutes. Now here is the restoration of peak power output. I've just put that chart up on the screen. And after 60 seconds of rest, around 50% of the power has been restored. And after 3 minutes, slightly more than 80% of the power output has been restored. After 60 seconds of rest, note that the muscle phosphocreatine levels are restored by approximately 40%, and then up to 80 to 90% after about 3 minutes. In essence, sufficient phosphocreatine is available to power a subsequent sprint after about 3 minutes of rest, at around 80% of the total power. Now it's not full power, you'd have to wait for about ten minutes to get full power. In contrast, let's take a look at the muscle pH. The muscle pH is indicated by the hydrogen ions, and this shows very little recovery even after 5 to 6 minutes of rest. Whenever glycogen has been used at a high rate, hydrogen ions and lactate will accumulate. And it takes roughly two hours to remove all the lactate and hydrogen ions from the blood and muscle if the athlete rests completely during recovery. Now walking or light jogging will restore the muscle pH in around an hour. In other words, light activity improves the speed of the hydrogen ion and lactate removal. So while lactate and hydrogen ions reduce during the four minute rest period, a significant level of lactate and hydrogen ions still remains. After about four minutes, you can expect around 90% of the athlete's sprint capacity to be restored despite the remaining acid conditions. Now I hope you are wondering why the athlete can continue with a high speed of training despite high levels of acidosis remaining in the muscle? And it happens or it appears that the resynthesis of phosphocreatine is the dominant factor influencing the performance of repeated bouts of high power. Acidosis does not interfere with the phosphocreatine energy system. And we're going to come back and address this further in a little bit.