Isolating exercises with more reps (12/15) can enhance muscle separation, the ability of different muscles and heads to separate and distinguish from each other.
This is also provided by super sets of antagonistic muscles (biceps and triceps).
But nothing builds thick and dense muscles as heavy weights with reps range 8/12.
This is the sarcoplasmic hypertrophy, that bodybuilding is about and stimulates the muscles. Single reps won’t lead to muscle growth, but will improve maximum strength, that will in turn increase the overall weights we lift under 8/12 reps range.
This is called as myofibrillar hypertrophy that stimulates the central nervous system.
The main fact about muscle growth is breaking down muscle fibers, achieved by high intensity.
Either by heavy weights, or by time under tension and short intervals between sets.
But mainly it’s about heavy weights and 8/12 reps range.
Of course we realize that weight is purely subjective to each one of use and it means we have to train almost to failure (like no other rep is possible).
Muscle growth is based on 8/12 reps range and 60-90 sec resting time between sets.
Muscle inflammation requires arachidonic acid, omega 6 fatty acid, plus the mechanical stimulus of resistance training to failure (lactate production).
Afterwards, proper sports nutrition along with specific supplementation (positive nitrogen balance) will ensure muscle growth.
Anabolic hormones include testosterone, AAS, growth hormone, and insulin like growth factor, insulin, mechano growth factor and myostatin inhibitors. S
upplements that help anabolic drive include creatine monohydrate, EAAs & BCAAs, glutamine and HMB.
Muscle growth deals with sarcoplasmic hypertrophy, while muscle strength with myofibrillar hypertrophy.
The former is achieved by the classic 8/12 range to failure, while the later with single reps of maximum strength.
Cross section of muscle fibers dealing with muscle strength and single reps (myofibrillar hypertrophy) appear thicker having more fibers of actin and myosin.
Muscles that lift heavy, have this muscle density and thickness and bodybuilders, who started as powerlifters, have this kind of physique.
Generally for muscle growth the main stimulus is to break down muscle that has to be repaired afterwards.
This is mainly achieved by heavy weights, however this is not exclusive.
During my bodybuilding carrier I realized that medium weights can still keep intensity high by keeping two out of three parameters of intensity.
Time under tension with strict form, full range of motion and short time intervals between exercises and sets.
Eccentric has to be 3x times slower than explosive concentric phase, while range of motion must be complete (better stretch, leads to better contraction).
Strongmen, powerlifters and cross fit athletes also develop the so called resistance in strength.
This technically implies the lactate tolerance threshold and deals with numerous reps to failure.
Calves, forearms and abdominals obey to the category of slow twitch read muscle fibers that require high reps and heavy loads in order to develop.
The use of NSAIDs (ibuprofen, diclophenac, nimesulid, salicylic acid) post workout, suppresses muscle inflammation and inflammatory cytokines prostaglandins.
Therefore it’s not a good idea to take those drugs post workout in order not to hinder this process. The reason we fell sore after a long break from training, is the accumulation of arachidonic acid.
Free weights and basic multi joint exercises with barbells and dumbells have to be done in the begging of each workout, when energy levels are higher.
Of course we need a good warm up and the start using some cables, or machines with light weight to pump some blood. Pre exhaustion isolation exercises are ideal before a multi joint basic exercise like bench press or squat.
So that would be pec dec, or leg extension machines.
Usually machines are used pre contest when energy levels are lower from dieting and stability is an issue in order to have safety and avoid possible injuries.
They are more about detail and practical for drop like sets.
In multi joint basic movements several different muscles are participating.
We have the main primary muscles and the antagonistic ones during the eccentric movement.
While we also have secondary muscle that stabilize the joint and provide support.
For instance during dumbbell flies, pectoralis major contracts during concentric phase, while latisimus dorsi contracts during eccentric phase.
Moreover biceps brachi provides some stability in arm as it is flexed vertically in 90 degrees. Same valids for standing military press where front head of deltoid gets stimulated in first place, while triceps plays a secondary role during the final part of the movement.
Similarly during squat lower back muscles (erector spinae) are playing major role to provide stability, being antagonistic with abdominal muscles.
For proper posture those muscles groups have to be equally trained, otherwise the more dominant muscle group will force the body towards that direction.
We have to train accordingly to time of recovery, otherwise we jeopardize our gains and catabolize.
After all, we break our muscles in the gym, we feed them in the kitchen and we grow them in bed.
Usually one or two times per week we train a muscle group. In order to train wise, we need to train in pairs of muscle groups (chest and triceps, back and biceps)