Posts made in January, 2013

Sports Nutrition Review 1-2, Hydration Status & Electrolytes

Posted by on Jan 31, 2013 in Nutrition, Review Topics | 0 comments

It’s common knowledge that hydration is important. Water affects performance more than any other nutrient. But what we’re concerned about in this post, is what details of hydration we need to know for the CSCS exam.

Voluntary Dehydration
Most athletes will only replenish 2/3 of lost fluids after exercise. This phenomenon, called voluntary dehydration is one that strength and conditioning professionals need to be aware of and encourage athletes to fully replenish their stores after exercise.

When does fluid loss lead to decreased performance?

  • A 1% loss in body weight of water leads to an increase in core temperature, however does not have a measurable effect on performance.
  • A 3-5% loss of body weight results in cardiovascular strain and impaired ability to dissipate heat, leading to performance degradation
  • At 7% loss, collapse is likely.

For example, a 200lb athlete may lose 10lbs while exercising in the heat (5% loss).  This is fairly common, but should be recognized as detrimental to performance.

Monitoring Hydration
A very accurate way to monitor hydration status is by weighing the athlete before and after exercise.  Each pound lost represents 0.5L of fluid loss and must be replaced before the next training session.

Electrolyte Replacement
Electrolytes lost in sweat are higher in untrained individuals vs. trained athletes.  The average concentration of sodium in sweat is 1.15g/L, with concentrations ranging from 0.46 to 2.3g/L (a big range).  Given that the average American salt intake is 4-6 grams per day, electrolyte loss in some athletes is common and can lead to cramping.  Additional salting may be necessary, as well as potassium rich foods such as bananas, potatoes, strawberries, meat, and milk.

In my next post, I’ll go over the general recommendations for hydration before, during, and after training sessions.

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Maintaining your Body with Kelley Starrett on Creative Live

Posted by on Jan 29, 2013 in Mobility, Personal | 0 comments

If you are in the fitness industry (or in my case, aspiring to be) I hope you have heard of mobilitywod.  It has changed my life.  Really.

Mobilitywod’s owner, Kelley Starrett is the founder of San Francisco Crossfit and is a Doctor of Physical Therapy.  His mantra, that “every athlete should be able to perform basic maintenance on themselves” is a powerful one.  His site has over 500 videos of various techniques to increase mobility and athletic power.

That’s my pitch for mobilitywod.  Now let’s talk about his Creative Live event.

Tomorrow, January 30, 2013 kicks off a two day video series titled “Maintaining Your Body”.  The live event is free, sign up here.

I will be trying to study while watching this and taking care of my son over the next two days, so I may not get any extra CSCS studying updates finished until it’s over.  However, I think taking a break for this opportunity is well worth it and you should too.  If you don’t watch the live event it’s available after the fact for $99.  Enjoy!

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Taking a Short Break, and a New Look!

Posted by on Jan 28, 2013 in Personal | 0 comments

I came down with a cold recently and haven’t had as much time to study, well actually I have…or rather, I did.  See when I was sick, I could sequester myself in a corner and spend a lot of time studying and writing posts.

As soon as I got better, my wife and my dad (who is visiting from Germany) both got sick.  Then I had to take on a full time support role of taking care of the wife and my 3 month old son.

We’re all close to full recovery now, so I’m hoping to finish out the rest of the topics I needed to review after my first practice exam.  Depending on how my second practice exam goes I may switch my study strategy.  Writing a post per question I missed has been a good experience so far, but it’s a little more time invested per question than I would actually need.  I would like to strike a better balance between generating content, studying, and time spent.

Also, you may have noticed a new look for the website.  I didn’t really like the old theme anymore, and I’m always looking to improve the readability and accessibility of this site.  Let me know if you have any thoughts.

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Sports Nutrition Review 1-1, Pre-Competition Carbohydrate Loading

Posted by on Jan 24, 2013 in Nutrition, Review Topics | 0 comments

On the practice exam, I missed four of the seven questions regarding nutrition.  It’s funny, because aside from my normal day job, this website, and my other activities I spend a good deal of time reading about nutrition related topics and consider myself well educated on the topic.  Some of this knowledge was useful in answering the questions, but many of the questions were geared towards nutrition as it pertains to athletics.

Also, there are a fair number of nutritional philosophies outlined in the CSCS Exam preparation materials that I simply do not agree with.  That’s largely irrelevant however, as the goal is to pass the exam.  Onward to the material!

Pre-Competition Carbohydrate Loading

Studies have demonstrated that an effective technique for increasing muscle glycogen stores before an endurance event, is to taper activity for the week prior to the event combined with a high carbohydrate diet for the three days immediately prior.  This has been shown to increase glycogen stores by 20-40%.  I haven’t covered what glycogen is yet, but it’s the storage form of carbohydrate that is stored in muscles and liver.  Read more about it here.

The recommended quantity of carbohydrates is 8-10g per kg of body weight.

So a 150lb marathon runner would load each day 544 – 680 grams of carbohydrate each day, or around 2176 – 2720 calories of carbohydrates.  This is around 6-8 lbs of potatoes, 20 bananas, or 12 cups of cooked pasta.

First convert 150lbs to kilograms by dividing by 2.2.  Then multiply this number by 8 & 10 to get your grams, and by 4 to get your calories.

This can seem like an excessive amount of carbohydrates, and some athletes poorly digest an excessive amount of carbohydrates so personalization may be necessary.

If you understand macronutrients, focus on remembering “8-10 grams of carbs per kilogram of bodyweight”.

When the question comes up on the CSCS Exam, you will then likely be able to deduce the answer if you remembered the above quotation.

 

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Exercise Science Review 1-6, Intro to Plyometrics

Posted by on Jan 23, 2013 in Exercise Science, Review Topics | 0 comments

Plyometrics is defined as a quick, powerful movement that begins with a counter movement, or “pre-stretch”.

Imagine you are about to take a jump, instinctively you bend at the hips and knees before exploding with violent hip and knee extension propelling yourself into the air.  The initial bend at the hips and knees is the “pre-stretch” and it stores energy in your muscle fibers and connective tissue and releases it upon contraction.  This is known as the Stretch Shortening Cycle, and as you can tell from the wikipedia article some of the science around exactly why this works is difficult to nail down.

Nevertheless, the bottom line is dynamically pre-stretching a muscle increases output power.  Whether this is by increased innervation from the CNS or stored energy in the elastic tissue, or some of both, the goal here is to know some of the theory and practical applications.

Muscle Mechanical Diagram

Muscle Mechanical Diagram

Above is a mechanical diagram that is often used to represent the components involved in the stretch shortening cycle.

Parallel Elastic Component (PEC)

The PEC or Parallel Elastic Component, is comprised of the epimysium, perimysium, endomysium, and sarcolemme.  It exerts a passive force when the muscles are being stretched but not activated.

Series Elastic Component (SEC)

The Series Elastic Component stores the majority of the energy in the plyometric exercise.  The SEC is comprised mostly of tendons, and they act like a spring.  As energy is stored during the stretch phase, the tendons lengthen and store elastic energy.  Following the eccentric phase, the energy is released if immediately followed by a concentric phase.  Otherwise the stored energy is lost as heat.

Contractile Component (CC)

The contractile component is exactly what it sounds like, the component of the muscle doing what we always expect muscles to do: contract.  Composed of actin, myosin, and cross-bridges as covered in chapter 4 of the book.  If you don’t know what those last words meant, start here on wikipedia: Actin, Myosin…though the wikipedia articles probably go into more detail than you need for the CSCS Exam.

There is more on plyometrics you will need to know for the CSCS Exam, specifically the three phases of the stretch shortening cycle as well as program design for plyometrics.  I will get into these topics later, but won’t be covering them in my first review series.

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