Most people think that the soreness u get after 1 day of training a body part means the muscle is growing. That is not necessarily true. It means that u have hit that muscle hard and inflicted some damage onit. whether it grows or not depends on different factors. If u want strength increases aim to minimise the soreness u get. Do this by decreasing the volume, not intensity, of ur workout. Lets say u train ur chest. Do 5 sets of heavy benchpresses, use a weight that u know will stimulate the muscle into growing. Then get the hell out. Shaping up the muscle is a different phase.here u can apply flyes, dips, and decline/incline benchpresses to really shape up the powerful muscle u built.[/quote]
Shape up the muscle?
Also, for your (OP’s) biological explanation.
Efforts that require near maximal loads will put a different stress on your body than when around 60-70 percernt.
Your muscle is bathed in a fluid called sarcoplasm.
This sarcoplasm contains many nutrients and the sorts that feed your muscle and allow it to operate.
When you do very high intensity, there is immediate attention put on the muscle and so the first thing that will give way is the muscle itself. We all know that doing exercise tears muscle fibers (known as myofibrils). Your muscle will also use up it’s store of ATP (Adenosine Tri-phosphate)
However, if you do low-medium intensity exercise , the stress on your muscle fibers isnt as great but after a time, you will feel that “burn” which many debate to be many different things. The point, however, is that the sarcoplasm is losing nutrients at a faster rate than the body can replenish and the muscles need these to move. This tends to be more aerobic.
Not to be confused with the ATP already stored in the muscles which is used for high intensity efforts - anaerobic.
Hence, people are told for strength to do 5-8 reps since the damage is done directly on the muscle and the sarcoplasm is only brought into play after the exercise is over (to replenish ATP).
However for size, 12-20 reps is better, since the “damage” is done through the sarcoplasm.
Your body tried to adapt on the stress.
By doing “moderate-high” rep, you re telling your body you need more nutrients (since the first thing to run out is the nutrients in the sarcoplasm, as opposed to muscle fibers being torn)so your body compensates by giving you more sarcoplasm. Which is why your muscles might look big, but feel soft.
An analogy that might help:
You have a car with 4 wheels and a full tank of gas.
Wheels are the muscles, ATP is the engine, transmission is the CNS and the gas/water is the sarcoplasm.
If you go really really fast the wheels will burn out and the engine will overheat. You then need to wait a while for everything to cool down…the gas/water do this.
Also, you wont last as long. You can only drive like this for…let’s say…half an hour.
If you go really slow, your engine is fine and so are your tires, but eventually you will run out of gas. You can drive like this for 2 hours.
The driver, aka your body, realises that:
-If he drives fast that his primary concern is the engine and wheels are the most important because they are the first thing to burn out. The gas isn’t as important since even at the end you have some gas left.
So the driver will buy better wheels and a better engine but leave the gas tank alone. The wheels and engine wont be better, but the material will be sturdied. To make his machine more efficient, he also upgrades the transmission.
-If he likes to drive slow since he needs to get somewhere further but can take his time, his primary concern will be how much gas he has left. Since there is little stress on engine, transmission and wheels, he leaves those alone but he buys a bigger gas tank. He might, maybe with time decide to upgrade his wheels, engine and transmission just a bit, since he does use them to a certain extent, but his main concern is the gas tank. However the only way to do this is to make his car bigger.
So the idea is that if you train to failure, more emphasis might be put on the sarcoplasm instead of the muscle fibers themselves. You’d have to read up on it. I think it depends on how you work to failure. If you do low rep high intensity failure as opposed to low intensity high rep failure, your body will adapt differently.
You’ll have to read up on it.
Take this with a grain of salt, but it’s what i’ve come to understand. If i’m off, please someone correct me.
Hope it made sense.