Paradoxical and Diaphragmatic Breathing
I began to hit on this in a previous post, On Breathing.... The purpose of that post was to introduce the fallacy of "expanding the chest". To do so I focused on strongmen of old and their ideas about ribcage expansion. Indeed, that was a fetish that followed into the early bodybuilding days and beyond.
There are still people who insist that everything old is good (or bad depending on their belief system) and so there are people who will insist that everything that happened in the strength training of yesteryear was pure genius compared to today.
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Muscle Cramps Part V
In the last article we introduced you to Randy, our imaginary 70 kg average male runner, and we created some potential scenarios regarding his fluid and sodium losses and replacement. The biggest take home message was to listen to your body and to drink to thirst, as this has been shown again and again in the field and the lab to keep people from drinking either too little or too much. We have received tons of feedback and discussion, and as we stated in the comments to that post we are pleased that so many of you are participating in the discussion, sharing your stories, and asking relevant and insightful questions.
Continue Reading » Muscle Cramps Part V
Muscle Cramps Part 4.5
This is a pseudo-Part V of our series on Muscle Cramps - I was tempted to call it Part V, but it's a little bit of a departure from what we've been talking about. In our next article, which we will be calling Part V, we'll wrap up this really challenging series and try to summarize all of the comments and our articles into one concluding piece.
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Theories and Fallacies of Muscle Cramps Part IV: An explanation of the evolution of science
Over the past three articles, we've taken what has turned out to be a pretty intense look at muscle cramps. We began with a discussion of how muscle cramps were first attributed to a low serum electrolyte concentration, without any substantial evidence for this theory. We then moved on to show that, in fact, people who cramped have the SAME electrolyte concentrations and levels of dehydration as those who do not cramp - this is pretty strongly suggestive that cramping is not caused by either dehydration or electrolyte depletion. Then in Part III, we described a new model for muscle cramps, involving a 'malfunction' in the reflex control of muscles during fatigue.
Continue Reading » Theories and Fallacies of Muscle Cramps Part IV: An explanation of the evolution of science
Theories and Fallacies of Muscle Cramps Part III: A Novel Theory for Exercise-associated Muscle Cramps
This marks the the third part of our series on muscle cramps. It was going to be the final installment in this particular series, but we've received some excellent and thoughtful questions and comments on the issue, so have decided that we'll do a fourth article, just summarizing some of those key "sticking" points. It seems from the feedback that this issue - electrolytes and cramps - is one of the more contentious ones around. So in our FOURTH article of the series, we'll look back and try to tie up any loose ends and conceptual issues.
Continue Reading » Theories and Fallacies of Muscle Cramps Part III: A Novel Theory for Exercise-associated Muscle Cramps
Theories and Fallacies of Muscle Cramps Part II: Electrolyte Depletion Model of Muscle Cramps
In part one of this series on muscle cramps we tried to set the scene by providing some history in this area. At times it might seem like we are a bit heavy on the historical side, but as we mentioned in one of our comments to Part I, understanding the historical record is crucial as often it helps us understand why we think what we do—-and this affects one's interpretation of the science. In this article we will focus on the prevailing premise that dehydration and electrolyte disturbances cause muscle cramps.
Continue Reading » Theories and Fallacies of Muscle Cramps Part II: Electrolyte Depletion Model of Muscle Cramps
Endurance Capacity, Not Body Size, Determines Physical Activity Levels: Role of Skeletal Muscle PEPCK
Some people remain lean despite pressure to gain weight. Lean people tend to have high daily activity levels, but the source of this increased activity is unknown. We found that leanness cannot be accounted for by increased weight-corrected food intake in two different types of lean rats. As previously reported in lean people, we found that lean rats had higher daily activity levels; lean rats also expended more energy. These lean rats were developed through artificial selection for high aerobic endurance capacity. To test whether our findings extended to a human population, we measured endurance capacity using a VO2max treadmill test and daily activity in a group of non-exercising individuals. Similar to lean rats selectively bred for endurance capacity, our study revealed that people with higher VO2max also spent more time active throughout the day. Hence, endurance capacity may be the trait that underlies both physical activity levels and leanness. We identified one potential mechanism for the lean, active phenotype in rats, namely high levels of skeletal muscle PEPCK. Therefore, the lean phenotype is characterized by high endurance capacity and high activity and may stem from altered skeletal muscle energetics.
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Theories and Fallacies of Muscle Cramps Part I
This is a follow-on from our series of articles on Fluid Intake and Dehydration, and as we were preparing to write this series, we realized that there may actually be even more nonsense and blatant lies in the media than there were for dehydration!
Continue Reading » Theories and Fallacies of Muscle Cramps Part I
Fluid Intake, Dehydration, And Exercise Part IV
So far we investigated the history of fluid ingestion in Part I, demonstrated why it is the metabolic rate that predicts temperature in Part II, and weighed up the strengths and weaknesses of the lab-based and field studies in Part III. For Part IV we will look at the thirst mechanism and why waiting until you are thirsty is not "too late."
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Fluid Intake Dehydration And Exercise Part III
Welcome back for Part III in this series on fluid intake and dehydration during exercise! Thus far we have examined a brief history of fluid replacement during endurance exercise in Article I, and in Article II we tried to explain how some of the lab research has perhaps been over-interpreted, and how that has lead to a false belief that ingesting fluid during exercise will keep you cool. In that article we reported the findings of earlier researchers who concluded the following:
* The core temperature is maintained at a higher level during exercise
* It is the metabolic rate (or in other words, how hard you are exercising) that predicts the core temperature
Continue Reading » Fluid Intake Dehydration And Exercise Part III
Fluid Intake Dehydration And Exercise Part II
This is the second article in our series on fluid intake, dehydration and exercise. In the last article we looked at the history of fluid intake and how radically our beliefs on the subject had changed. Today we turn our attention to the evidence that has accompanied this shift, beginning with the contention that runners who become dehydrated are likely to develop heat stroke.
Continue Reading » Fluid Intake Dehydration And Exercise Part II
Fluid Intake, Dehydration, and Exercise Part I
The story begins, as most do, at the beginning…a look at the history of fluid intake and drinking during endurance exercise, which serves to illustrate an important point, one which will be covered again and again in this series…For this post, we acknowledge Professor Tim Noakes of UCT, the fluid pioneer whose lifelong pursuit of the truth in this area (and a lone battle for much of it) has thrown up the excellent quotes and anecdotes we use as we delve into the issue.
Continue Reading » Fluid Intake, Dehydration, and Exercise Part I
Cortisol
Cortisol is the primary member of a family of glucocorticoids, and is considered the main catabolic hormone. Corticosterone is the other glucocorticoid, but is thought to be much less potent than cortisol (accounting for approximately 4-5% of total glucocorticoid activity). Cortisol is made and secreted from the adrenal cortex, via the hypothalamic-pituitary-adrenal (HPA) axis, with a small amount also derived from the conversion of cortisone.
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Stretch Reflex with Passive/Static Stretching
The stretch reflex, or myotatic reflex is a neural mechanism that responds to changes in muscle length (stretching) by attempting to resist the change in length. The changes in length are detected by proprioceptors called muscle spindles. Changes in muscle tension are detected by another important proprioceptor, the Golgi tendon organ (note: there may be other processes at work).
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