Interesting answers by different scientists:
[1] Muscle Glycogen: does resistance training deplete it systemically, or only in the muscles used at the time? âŚMore
Interesting study on rats:
[2] Depletion of muscle and liver glycogen during exercise: ââŚResting glycogen stores in the liver were higher and were depleted more slowly during exercise in the trained than in the untrained animals. Blood lactate concentration was significantly lower in the trained than in the untrained rats at the end of the exercise test. These results provide evidence that endurance exercise training induces adaptations which protect against the depletion of glycogen from the liver and from the three types of skeletal muscle during prolonged exercise. âŚâ
This is really interesting:
[3] ââŚTwo approaches to creating a state of low carbohydrate availability are often described simultaneously, as if theyâre simply different but equivalent ways of going about it:
a) exercising after an overnight fast - stores of carbohydrates are used while you sleep and not replaced before a workout, or
b) exercising after a prior heavy exercise bout - carbohydrate is used up during an exercise bout and not replaced before a second workout.
Despite being presented as equivalent options, the two approaches are different in their bioenergetics and will lead to different adaptations. This episode is meant to clarify the physiology of the two approaches and to present additional concepts related to fat vs carbohydrate usage for fueling your ultra endeavors. âŚâ âŚMore
Body By Science stuff:
[4] ââŚâLow-intensity, steady-state (popularly referred to as âcardioâ) activity does not tap the fast-twitch muscle fibers that possess the most glycogen. Consequently, the muscles are never emptied of meaningful levels of glucose, with the result that the circulating glucose has nowhere to be stored â except as body fat.â
âThe center of metabolic health is not the heart and cardiovascular system; it is the muscular system.â
âHuman beings require periodic bursts of high muscular effort. In the absence of such activity, glycogen is not drained out of the muscles to any meaningful degree. When this state is coupled with routine consumption of large amounts of refined carbohydrates, a level of glucose is produced that can no longer be stored in the muscles. The muscles are already full, because an insufficient number of glycolytic fibers have been tapped. Glucose therefore begins to stack up in the bloodstream, and the bodyâs insulin levels rise. Because the glucose cannot get into the muscle cells, the receptors on the surface of those cells become insensitive to insulin. The body then produces even more insulin and now has large amounts of circulating glucose and large amounts of circulating insulin.â âŚâ âŚMore
[5] The 20 Best Glutes Exercises of All Time
[6] Eccentric training focuses specifically on the lowering movement. And we slow the lowering time way down. Most trainees will be able to do this exercise with greater resistance than the lifting and lowering. This will cause your muscles to generate more force and build greater strength. âŚâ âŚMore
[7] ââŚAn eccentric movement is the lowering part of a move. Itâs when your muscle works as itâs lengthened, like those glutes do when youâre lowering into a squat, or like your biceps do as youâre lowering a dumbbell after a curl. And, in turns out, every muscle fiber in your body is the strongest as it moves eccentrically.
Itâs not just because of gravity. When muscles work eccentrically, more of the parts of the muscle used for contracting remain attached to each other at any given time, so together they can produce more force. There may also be increased tightness in some proteins within the muscle fiber during eccentric actions, which make the muscle more taut (aka strong). Hence why lowering into a squat feels a heck of a lot easier than getting back to standing. âŚâ âŚMore
[8] ââŚOne thing to keep in mind is that at 362, squatting (per @atomicspacebunny - working the glutes) is similar to a 200 person doing squats with a 100 pounds bar on their back (not a 162 pound bar because weight is distributed around your body).
So, if you start out doing âair squatsâ (squats without a bar) and practice form and getting low (which will take time) you can - as you lose weight, retain the fat burning and (once uncovered) great looking set of glute muscles. Drop 25 pounds, squat with a 20 pound dumbell, drop 75 pounds, squat with a 50 pound bar - as the weight comes off the body, add it to the bar. It will seem easy and - especially as you get older - you want to avoid muscle loss if possible (which is inevitable as you lose a lot of weight but still worth fighting against). âŚâ âŚMore