Thursday 110512

For Time:

25 Walking lunge steps 
20 Pull-ups
50 Box jumps, 20"
20 Double unders
25 Ring dips
20 Knees to elbows
30 Kettlebell swings, 32kg (54kg)
30 Sit-ups
20 Dumbbell hang squat cleans, 35# (25#)
25 Back extensions
30 Wallballs, 20# (14#)
3 Rope climbs

Post time to comments. 

Rookie and Adam, improving their O2 transport systems.

Cardio-Respiratory Endurance – Now what does that really mean?

We often talk about the 10 general physical skills associated with CrossFit.  At the top of the list you have cardio/respiratory endurance, an organic adaptation, but what does that mean literally? 

It refers to the ability of the body to gather, process and deliver oxygen.  To us this looks like the body performing work, any work; running, pressing or swinging over a longer period of time.  The physiology of the body that makes this happen or that we are "working", includes the cardiovascular and respiratory systems.  The heart, arteries, veins, fluid (blood), and lungs; work in symphony to supply oxygen to your working tissues, the muscles.  

Your heart is simply a muscle with special cells that conduct electricity.  When you are doing physical activity, you are training your heart to beat stronger and to be more efficient.  That means for every beat of your heart you will have an increased cardiac output.  Cardiac output is measured on how much blood your heart can pump out with each contraction.  The better shape you are in, the more efficient your heart can move blood, or the quicker you transport oxygen to your tissues.  Which in turn means; when you are at rest, your heart will require less beats per minute because it is so efficient.  

With every breath you take your lungs are exchanging carbon dioxide for oxygen. Carbon dioxide is a toxic by product of your respiratory system.  Inefficient exchange of carbon dioxide is toxic to the heart and causes diminished contractile force.  


As you train your heart and lungs, you train your systems to be more efficient in there exchange of gases and transportation of oxygen to feed your hungry muscles.  Now who doesn't want a better, stronger, faster engine under the hood?


  1. Matt :

    Thanks for making HD&CC so much fun the last couple of days. My little cupcakes… all growing up to be such strong CrossFitters.

  2. Tobias Coffin :

    Hot Dogs and Cup Cakes is fantastic, and my last WOD looks pretty awesome too!

  3. bill :

    I love hd&cc! Before coming here I felt like I had to choose between Xfit and lifting weights, hd bridges the gap where I can do everything I want. I’ve also learned a lot about how dynamic effort is a different way to train for strength/speed, never would have tried half the stuff we do on my own.

  4. Pottsie :

    Rest day! So sad..

  5. AnnieCam :

    Ohhhhhhhhhhhhhhhhhhhhh…today looks sweet!

  6. I’m confused. I’m signed up for the 10am WOD on Saturday so does this mean I’m inadvertently signed up for the Steve’s thing?

  7. Matt :

    That’s correct!!!

  8. Matt,
    I have 10 people coming Saturday, what do I need to do to sign them up?

  9. David S :

    19:28 RX

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