Showing posts from 2016

Relationship between aerobic and anaerobic metabolism

Some coaches will speak of the elements of performance as exclusive concepts. Aerobic and anaerobic metabolism for example. Traditionally, the two could be separately defined, but we've known for some time now that the two are essentially bound in a symbiotic relationship. They're both a piece of the pathway that creates ATP. A typical physiological response from high intensity intervals, sprints, a finishing kick or a high intensity (<30 min) race is an accumulation of lactate and H+ ions. We know an accumulation of H+ ions (acidosis) will decrease performance capacity. The table below from Cairns, 2006 lists some proposed mechanisms through which acidosis inhibits performance. If only there were a mechanism in place to remove these pesky ions... Then, we could perform at a higher intensity for a longer period of time. But wait, there is! Oxidative phosphorylation, more commonly known as the electron transport chain or "aerobic metabolism," consum

Economy Notes

Below, I've started creating a list of factors that influence running economy. Here, I'll define economy as the steady state O2 consumption required to maintain a given running velocity. This list is more of an open note that I intend to periodically update and modify as I, and we, learn more about running economy. As you can see, there are quite a few factors that can influence economy. Let me know if you think of any others! Training Strength/plyometric training Stiffness/flexibility Training volume Altitude training Pace/Power output Substrate utilization Training specificity Running Form Mitochondrial quality Uncoupling proteins Influence of training Heritable Substrate availability (O2 & CHO) More economical to burn CHO More economical when O2 availability is limited Fatigue VO2 slow component Motor unit activation - number and "type" Fatigue VO2 slow component Anthropometrics Body mass distribution Ankle/wrist circum

Warfarin and Bone Health

I don't imagine this post will be relevant to many of you. Maybe you'll find it to be an interesting topic in physiology and medicine. But I want to put it out there to increase awareness, just in case any one has concerns over Warfarin use or is looking for answers. This past fall, I had a pulmonary embolism. This was my second, unprovoked episode -- the first occurred in 2011. Usually after the first event, you leave the hospital with a prescription for an anticoagulant (blood thinning) medication and you'll take it for anywhere between 3 and 12 months. After the second episode, your doctor will likely suggest you stay on anticoagulants indefinitely (or until gene therapy becomes avalable). There are a few anticoagulant options out there now -- Coumadin, Eliquis, Xarelto, and Pradaxa to name a few. So, how did I choose Warfarin? Coumadin, generically known as Warfarin, is the oldest of these anticoagulants. Having been around since the 50's we've had a lot of