Starting a new training modality or coming back after a long break your muscles will most likely become sore for a few days as a result. In high school, being involved in weightlifting through a class they offered, I would come back from long breaks to the weight room, work out, and be sore for the next week. I didn’t have my own car at the time, the weights at home weren’t sufficient, nor did I know the possibilities that could be achieved with other forms of training.
Then, signing up for military service the next few years of my life had periods where there would be some long hike or swim that I would need to participate in. Due to the fact that I didn’t perform such movements regularly, I would always be sore afterward.
Delayed Onset Muscle Soreness (DOMS) occurs when due to repeated and strenuous movement your muscles become partially damaged. When they are damaged they are repaired by rest and nutrition. The nutrients help to repair not only what was damaged but if the right signal or stimulus was activated by the workout, the growth of that muscle. DOMS can come mostly through eccentric deceleration aka the lowering phase of a movement. Meaning if you do a large number of pistol squats before you go out the wire your legs might be hindered in their performance. This is why from time to time I have pondered about concentric emphasized training. As this minimizes muscle damage and still gets the job done of making you stronger and bigger. Muscle Damage still occurs but with DOMS, depending on the context it might be a sign of one going overboard.
Each muscle fiber is made up of structures known as, “Myofibrils” which are the contractile component of the muscles among other elements. It is this part that if your training is perfectly aimed, will create a build-up of these myofibrils providing a denser look to the musculature you pack on. If you’ve ever seen a picture of a hairless chimp this is the idea I’m going for.
Within these myofibrils are smaller filaments known as actin and myosin. During contraction and relaxation, these filaments will be sliding past each other creating heat. This is known as, “Sliding Filament Theory.” Small bridges rubbing between each other constantly would create some damage and soreness.
With overcoming isometrics even though there is no movement in your limbs(at least not much) your muscles will still be contracting. And when they are contracting the sliding filament theory is taking place only it's not as repetitive. You get in place, you breathe, ramp up, and exert with all your might.
In an ideal isometric contraction, all your myofibrils with the actin and myosin in them will be activated and bunched up. But nothing is perfect and you may have an exertion phase where you are aiming for 90% intensity but shift in and out of the 85% range for most of it with a few split-seconds close to 90%. This shift will dictate a greater number of filaments coming together and disengaging creating heat and possible damage(aka sore muscles). It takes practice and I’m still learning.
“More muscle can be exerted in Functional Isometric Contraction then by contraction where by means of movement, the muscle is allowed to shorten. There is more cell growth as a result of Functional isometric Contraction.” (p 5 Hoffman Functional Isometric Contraction)
With any kind of movement, your muscles will be at varying intensities of contraction throughout the range of motion. At the top of the movement/the extended portion, there will be the least and as you go down to the middle range and then the stretch your muscles activation will be higher and higher. Then you press back to return to the top position where there’s the least amount of tension even if you are keeping a small bend in your joint to maintain tension. This is why you’ll see some folks lifting with chains on their bars as these help to maintain a considerable amount of tension throughout the entire range of motion. Another option for this is to work on your mind-muscle connection and maintain the tension through the entire range of motion yourself.
