A Little Physiology
Mike Gittleson was the Director of Strength & Conditioning at the University of Michigan for 30 years and and was a part of 15 Football Championships in that time. He explains, that learning is a life long process.
At the age of 53 I had to retake the course Molecular Biology of the Cell. One of my former students, and a doctoral candidate who had previously worked in our weight room, wrote a paper on p70s6k and its relationship to increased skeletal muscle mass. Dr. Keith Baar's discovery was absolutely significant to what is known as the mTor pathway.
He showed a strong correlation between the magnitude of the load placed on a muscle, the activity of the mammalian target of rapamycin (mTOR), and muscle growth and suggested that the mechanical load was the primary determinant of muscle growth.
He called me about his discovery and sent me a copy of his paper. I was embarrassed because I didn't truly understand what he had written. The good news was I thoroughly enjoyed reading it because I knew it was important and Dr. Baar was important to me.
As a coach I had always preached about education, the importance of continual learning, and meaning what you say. So if I was going to pass on information to others I had to remain current as I pulpiteered and.... Sooo....it was back to school!
A Short Little Physiology Lesson And A Few Things I Learned
Muscles care about tension and don’t know sets reps or how the tension came about. They respond accordingly to an unknown stressor. Muscles also care about their metabolic state, which, in the context of a workout, is also a function of time under tension.Key regulator of muscle protein synthesis after training is the mammalian target of rapamycin or mTOR.
The mTOR pathway is influenced by the intracellular concentration of ATP/GTP.
GTP is used as an energy source in protein synthesis. It's also responsible for enegy transfer and to transmit signals throughout the cell.
mTOR activity is blocked by metabolic stress or ATP – high energy cost. This dictates ATP/GTP levels, oxidative stress, and calcium flux, and other things— all of which feed into various pathways which regulate mTOR signaling. The concept of the repetition in weight training gets complicated when you consider all this stuff.
Cells within tissues are subjected to mechanical forces caused by extracellular matrix deformation. Cells sense and dynamically respond to stretching of the matrix by reorienting their actin stress fibers, and by activating intracellular signaling proteins. Fiber organization is altered and to an extent dependent on stretch frequency.The implication being that activation of mTOR and therefore muscle growth is entirely dictated by the mechanical load the muscle experiences.
When there are many muscles involved in functional movements and lots of tissue to be loaded, overloading the target muscles may require performing higher rep work especially as lots of levers are working, turning off and turning on particular muscular groups. This way all the muscles involved in the movement have TIME to be stimulated.
Thus there are more studies coming out like the 2010 ....Low-Load High Volume Resistance Exercise Stimulates Muscle Protein Synthesis More Than High-Load Low Volume Resistance Exercise in Young Men.....McMaster University, Hamilton, Ontario
Molecular physiology will continue to challenge our thinking and to stay on top of the iron game we will have to stay very current. Our brains will have to have very quick and explosive synaptic flow...
Soooo stay tuned the molecules have a lot to say about how to Get Strong.