The
cardiovascular system is responsible for delivering oxygen to the body’s
tissues. It works in conjunction with the circulatory and respiratory systems
and is comprised of three separate energy systems. Each is designed to perform a specific task
but are interwoven together to complete tasks such as sprinting, jogging and
jumping. There are two primary forms of
energy, anaerobic and aerobic. These energy systems utilize a form of energy
called adenosine triphosphate or ATP, which is produced by the body from food. ATP
allows muscle function and in turn movement to take place.
The
anaerobic energy system can be broken into two sub categories, the creatine
phosphate (CP) and anaerobic glycolysis. These energy systems function in the
absence of oxygen which places the body’s tissues in an oxygen depleted state
that must be repaid. These systems operate under very extreme intensities when
the body is unable to keep up with its oxygen requirements placed upon it; this
is called the anaerobic threshold or lactate threshold. This energy system
relies primarily on glucose or glycogen as a fuel source (broken down
carbohydrates) which is one of the reasons our diets must contain carbohydrates.
When anaerobic metabolism takes place due to the lack of oxygen it produces
several byproducts that conflict with body’s ability to function. When enough
of these byproducts are produced muscle function is inhibited and eventually
movement is impaired. Let’s take a closer look at the two energy sub systems
that make up the anaerobic system.
The CP
system is responsible for immediate energy requirements such as short sprints
and jumping. It can create ATP almost immediately but only for a limited time.
It is the primary energy system during maximal effort activity for the first 10
seconds. It is extremely important for most ball sports, all types of
resistance training and Olympic lifting. Unlike anaerobic glycolysis this
system functions utilizing creatine phosphate. You might have heard of the
supplement creatine which has been widely used as an ergogenic aid during
weight lifting. The supplement creatine is a man made version of what your body
uses during activation of the CP system. The basis behind creatine
supplementation is increasing the creatine stores in the body which will result
in the ability to utilize the CP system for maximal effort activity such as
resistance training or jumping.
Our
next energy system, anaerobic glycolysis is the primary energy system during
activities such as long and multiple sprints. It is much like the CP system
producing energy at a very quick rate and also generating byproducts due to the
absence of oxygen which eventually inhibits muscle function and movement.
Anaerobic glycolysis creates ATP through the metabolism of glucose and glycogen
and is the primary energy producing system between 30 seconds and three minutes
of continuous maximal effort activity. It is also extremely important for most
ball sports due to a number of variables (lack of rest, lack of intensity,
etc.). It is also important for short to mid distance running.
The
aerobic system takes over after three minutes of continuous or non maximal
activity. It is able to metabolize fats and carbohydrates for ATP creation.
Unlike the prior two energy systems it utilizes oxygen to produce ATP which
means it doesn’t create movement impairing byproducts. This is the energy
system that is responsible for long distance runs. It is also important for
most ball sports because it is responsible for breaking down the byproducts
during recovery and rest. When most fitness professionals think of aerobic work
they instantly confuse this with long slow distance runs that have been linked
to causing decreases in power. Aerobic capacity or commonly referred to as work
capacity is important for recovery both during activity and as a way to
facilitate blood flow through tissues. Imagine a basketball player sprinting
back and forth on a court for two and a half minutes. This athlete would be
utilizing the CP system for maximal effort movements such as quick cuts and
jumps and utilizing anaerobic glycolysis to get up and down the court. As
discussed above this athlete’s body would be generating byproducts that are
slowly decreasing his ability to produce force optimally and causing fatigue.
The coach notices that the athlete has become sluggish and finally gives him
some time to rest and recover, the aerobic system kicks in and begins breaking
down the byproducts and returns the athlete back to an optimal performance
level. Let’s take the same athlete
again, he has just completed a demanding away game against a rival opponent.
Utilizing aerobic conditioning such as tempo runs can help facilitate blood
flow through the muscles that were used in the event. This increased blood flow
will help with the tissue rebuilding process (remember tissues must break down
and rebuild to adapt to added and new stresses).
Each
and every energy system has a specific and secondary task, whether that be
fueling the muscles for explosive powerful movements or helping the body
recover from a task. These three energy systems are interwoven and must all be
accounted for when training athletes to optimize performance.
