A massive mistake you may be making in regards to intensity in the gym is not using mechanical tension. What do I mean by this?
Easily explained mechanical tension is taking the weight and using it through the reps FULL range of motion in a continuous fashion, this creates an elastic band effect.
Where most people go wrong is they just pump the weight up, and let it drop down, not controlling either, there is no tension during those reps. If I was to say a complete rep was 100%, most newer lifters are only utilising 30-40%, which comes in the eccentric contraction ( when the muscle shortens .
This problem usually lies in you using too much weight and not enough range of motion, thus creating no tension placed on your muscle fibres through the majority of the lift.
Although rest is vital in achieving progressive overload, as the muscular energy systems need rest before they can max out again. There are times you should be decreasing rest, Less rest equals more calories burned due to a higher heart rate, which increases the intensity of your workout.
Alot of fitness competitors tend to lower their rest as they want to get leaner for a competition, to increase daily caloric expenditure.
For lifts primarly focused on progressive overload, its best to wait until breathing has returned to normal ( if your breathing hasn’t peaked then the weight is way to light ). Then after your strength lifts are finished, you can start at 1 minute rest between exercises, slowly decreasing by 15 seconds every 2 weeks. Until 30 seconds rest is reached. If you arnt sweating in the 8-12 rep range with 30 seconds rest, your cheating, or your going too light, which brings me to my next point.
WORKING AT THE RIGHT LOAD
”Everybody wanna be a bodybuilder, but don’t nobody wanna lift no heavy ass weight!”
Its true, lifting heavy alone will not build maximum muscle, or a fantastic physique, but progressively overloading your muscles will.
If you dont incorporate every single rep range into your session, or week, or monthly split, your missing out on massive muscle gains. However, thats not the biggest issue, the biggest issue is load. If you cant build muscle, its likely your not loading right,
This can be fixed easily. Test for true 1 rep maxes ( go to your ABSOLUTE LIMIT ) on SQUAT, DEADLIFT, BENCH PRESS, OVERHEAD PRESS. You will have a number, during 8-10 rep work you should be using 75-80% of your 1rm to build maximum muscle, lower reps a little more, and higher reps a little less. Going off this basis should throw a whole new level of intensity at you, and whole more muscle too