DO NOT MAKE THE ROUND TRIP
There are exercises that are stressful. Anyway, you should not make the mistake of making only half because instead of making you a favor, stop working the entire muscle and you risk being curtailed.
It is better to reduce the intensity and do the exercise with perfect technique. Nor can you? Then start with simple exercises!
INSTEAD USE THE INERTIA OF MUSCLE STRENGTH
It’s a common mistake to use the inertia for an exercise. The danger: thus very difficult to control the exercise and the risk of injury. Precisely the classic crunches are often executed incorrectly. When you go down, do not just let you fall on your back. The trunk should be lowered gradually until reaching the shoulders almost touching the ground.
RESTING TOO LONG
It is important to take breaks during training for the muscles to regain their ability to contract. But if these pauses are too long, the muscle is cooled and then needs some time to warm up again. The problem: for warmth spent precious energy that you may need later during training. Try to rest less time between sets and thus end up well before training.