REST BETWEEN SETS

I don't understand why all weight rooms don't have a clock in site. The amount of time between each set, and each exercise is extremely important. There are numerous reasons for this, so lets examine them.
1)Metabolic Recovery- Adenosine triphosphate (ATP) is the source of energy used in weight lifting and strength/speed events that last typically less than 10 seconds. You can have explosive events/exercises last longer than that, but that is the norm for many sports. The body is able to restore or replenish certain levels of ATP after certain rest periods. The following is considered the approximate norms per many physiology studies and texts.
30 seconds>>>>>>50% of ATP is restored
60 seconds>>>>>>75% of ATP is restored
90 seconds>>>>>>87% of ATP is restored
120 seconds>>>>>93% of ATP is restored
150 seconds>>>>>97% of ATP is restored
180 seconds>>>>>98.5% of ATP is restored
This is why some people who don't take enough rest between sets, are unable to perform as well as they like. For example, freshman who are in a hurry to go hang out with their "friends".
2)Neural recovery- Is the ability for the Central Nervous System (CNS) to recover between sets and exercises. This is not as easy to monitor because of the huge effect that lifestyle plays on the CNS. If I have an athlete who sleeping, eating, and rest/recovery habits vary from day to day, the CNS will not have an opportunity to recover. It has been stated that the CNS recovery takes three times as long as a muscle to recover from a work out. Some very good strength and speed coaches know how to manipulate this area, but if the athlete is burning the candle at all "three" ends, then it is inevitable that the athlete will overtrain. I will be writing on this topic and related areas in many future articles.
3)Work/Rest ratios- Unfortunately, this can only be used in small groups during weight training or field work. If you have athletes in a various states of conditioning, exercise familiarity, and desire to achieve, you need to brake these individuals into smaller groups to really achieve the results you want to see as a coach, parent, or athlete. For example, if you are doing sprints at a specific distance, will athlete A be able to hold form, while athlete B doesn't have the experience in running form. Or athlete B needs more time for recovery between sprints. More sprints at longer distances, with shorter rest won't make up for a crappy diet. I wish a lot more athletes, parents and coaches understood that simple fact. The separate area of Aerobic fitness is overlapped to some extent in that explanation.
4) Bodyweight composition- Hey, if you get someone who looks like frosty the snowman running next to another fit athlete you know what I'm talking about. Body composition, or how much bodyfat the athlete has can fill you in on desire, self-esteem, dietary direction at home, and many other issues. This is a can of worms that everyone is familiar with.
5) repititions and the rest between sets- If an athlete is doing a high rep, machine oriented conditioning type workout, you won't need as much rest as a lower rep higher intensity workout. Each workout has a different goal or emphasis, so the rest periods work in conjunction with this.
6) Training experience- I usually like athletes to take a little more rest between sets, when they have been lifting for less than one year, and/or under the age of 16. That are factors such as secondary sexual characteristics, discipline, attitude, etcetera, that also play into this.
I hope this article give all interested the importance of rest periods.