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Monday, August 12, 2013

The Difference Between "Strength", "Power", & "Endurance"

So, what makes people different with specifics to strength, power, and endurance?  To make this answer not so complicated, it comes down to the make up of muscle fiber type, fuel supply, and the size of the spark plug you have in your body.  Spark plug?  What the...?  When I say spark plug, I'm referring to your nervous system.  In the previous post, I put a chart up that gave guidelines of how to specifically train for your goals.  Muscle fiber type and fuel source are also extremely important and I will get to this in a moment.

How The Nervous System Plays A Role In Training and Performance

Each muscle cell or fiber contains nerve innervation.  It has to right, in order to contract?  Some muscle fibers contain more motor nerves than others.  If a muscle fiber contains more nerve innervation, then this increases the muscles ability to fire, explode, contract, put out power!  You get what I'm saying.  A good example of someone with this type of nervous system would be an offensive or defensive lineman on a football team.  There are many other examples, but I think most of us can relate to the football linesman.

How Different Fuels Play A Role In Training and Performance

What you eat is extremely important for training and acquiring your fitness goals or for a specific sport or competition.  The following are different analogies regarding the various fuels available to us in our bodies.

If you go to a gas station, you get to choose what kind of fuel your car runs on.  You typically have 3 choices of octane fuel.

1.  High Octane Fuel Many of the turbocharged and performance sports cars run on high octane fuel.  A good analogy would be the same as direct fuel injection into the cylinders of a car.  The muscles are taking a fuel from the immediate available blood supply at the very moment it is called upon.  This fuel source is ATP (adenosine triphosphate).  ATP is an instant source of energy but is exhausted very quickly.  

An example of someone using ATP as their main fuel supply for their activity or sport would be a 100m or 200m sprinter.  Another example is an Olympic Power Lifter.  These people perform at maximum capacity but are only able to attain this level of exertion due to the quick depletion of ATP and a very rapid build up of waste product or lactic acid.

2.  Mid Octane Fuel - When referencing fuel for the muscle in the mid-octane range, this would be a combination of immediate blood glucose and conversion of stored glycogen in the liver of which then gets converted to blood glucose of which then gets converted to ATP.  The process for this to occur in our bodies requires a certain amount of time.  It's not an instant fuel source like ATP.

An example of someone using the "mid-octane fuel" would be a middle distance runner such as a 800m to a 10K runner.  Often, this fuel source can be available up to 1 - 1 1/2 hours of medium high physical exertion (i.e. exercising or working at 70 - 85% of maximum exertion).

3.  Low Octane Fuel -  Low octane fuel would be the 87 rated gasoline.  When applying this analogy to the body we are talking about using adipose or fat tissue for the fuel supply.  The process for fat or adipose tissue in our bodies to convert to useable energy takes a much longer time than ATP, blood glucose, or conversion of liver glycogen to ATP.

An example of someone using the "low octane fuel" would be someone running a marathon or cycling for a long period of time.

Fuel expenditures will vary from person to person.  The body can also be trained to a certain extent to utilize various fuel sources.  But, given our genetic makeup, not all of us can be elite class athletes no matter how hard you try or what supplements you take.  The genetic makeup in our bodies are key to how each of us perform individually.

But Hold On Just A Second!!  What About Oxygen?

Oxygen is key to "Converting" these fuel sources into useable ATP.  This is done during the Kreb's cycle.  Ask any high school or college student taking biology based classes about the Kreb's cycle and they'll tell you all about it!  Yes, the more oxygen that is available, then there's more potential for creating useable ATP for muscle contraction.

Then There Is The Muscle Fiber Type

Most likely you've heard the terms "fast twitch", "slow twitch", and then a combination of "fast & slow twitch" muscle fibers.  These muscle fibers are then classified even further into sub-categories that have  various combinations of fast and slow twitch muscle fibers.

A fast twitch muscle fiber typically uses ATP for fuel and is heavily innervated with motor nerves (e.g.. an olympic lifter or sprinter)

A slow twitch muscle fiber uses fat stores or adipose tissue for fuel.  Typically, the slow twitch muscle fiber has less motor nerve innervation (e.g. a long distance swimmer or runner).

And finally, the combination of fast & slow twitch muscle fiber.  This muscle fiber has a mixed amount of motor nerve innervation.  Meaning, it doesn't have as much motor nerve innervation as the fast twitch but it also doesn't have as few motor nerves as a slow twitch muscle fiber (e.g. a middle distance runner or swimmer) 

In Summary We Have:
  1. The type of muscle or motor
  2. The nervous system or spark plug that innervates the muscle
  3. The various fuels:
      • ATP (adenosine triphosphate)
      • Glucose in the muscle cell and circulating blood
      • Glycogen stored in the liver which then gets converted to glucose and then is available in the circulating blood
      • The break down of fat stores which is then used for available fuel in the blood  
      Here's a little trivia.  In the last post regarding Sets & Repetitions there was a mention of lactic acid.  Lactic acid is sometimes used as a fuel too.  The myocardium or heart muscle is able to use lactic acid as a fuel source.  Cool huh?

      We Can Now Define "Strength", "Power", & "Endurance"

      Not to draw this out, and relying on the information given previously in this post, a person who is:

      "Strength" or when considering when someone is strong is when this person has heavily innervated muscle fibers of which allows a very large recruitment of muscle while performing work against a maximum amount of resistance for a very short period of time or for just one movement.  This would be like shot putting, javelin throwing, Olympic lifting, etc.

      "Power" is when someone is able to perform a maximum amount of work over a specific period of time.  Someone that would be considered powerful would be a elite cycling time trialist.  This person has a specific amount of distance to cover in the least amount of time.  Maybe a better analogy would be a drag racer.  These cars have to be extremely powerful in order to be the fastest in a 1/4 mile run.  Savvy? 

      Here's a little trivia again.  Many people are familiar with "Olympic Power Lifting".  To me this is an oxymoronic term.  It should be just "Olympic Lifting" or "Olympic Strength Lifting" or something along those lines.  The athlete is performing work against a maximum amount of resistance for just one lift.  This is for the most part the definition of strength.

      "Endurance"is simply the ability to endure or last.  No matter the work load or resistance, eventually a person or the part of a machine will wear out given the work being performed over time.  An elite marathon runner is performing an endurance sport.  But because this person has trained for this and has developed a specific skill to complete the marathon in a much faster time than your average joe, they are still enduring a given workload over a period of time.  Yes, a marathon runner could be considered powerful, but given the work done over time, this person has more endurance than power.  Other examples would be Olympic distance triathlons, open water swimming competitions, basketball players, boxers, soccer players, etc.  A lot of work is being performed over a long period of time.

      I hope this post gives you a better understanding of strength, power, and endurance.  If so, you are now better informed and will be able to plan your workouts and acquire your goals with greater ease and less confusion with just how you should be training.

      As usual, feel free to email me for any questions or advice!

      Good Health To All,

      Brad Senska, PT, DPT, BS, ASTYM.