The purpose of resistance training is to induce maximal exertion to break muscle tissue down, stimulating supercompensatory muscle protein synthesis. The way to maximise this muscle growth is to get the most from each set, so in order to do this you need to think about the positive and negative phases of a rep!
Using a lat pull down as an example, the ‘pull’ is the positive phase whereby the muscle is in a concentric (muscle contracts and shortens) state, whilst the ‘release’ back to the starting point is the negative phase with the muscle being in an eccentric state (muscle contracts and lengthens). So in order to get the most out of your rep you must ensure that you pay as much attention to the negative phase of the rep as you do to the positive!
Double pronged attack
Utilising both phases of a rep encourages maximal muscle stimulation. The active recruitment of every sarcomere (basic unit of a muscle) is key to inducing deep muscle growth, and the way to activate EVERY part of the muscle is to perform the full range of motion at a constant rate. There should be no relenting during a workout, if you walk out not breathing heavily then you probably haven’t worked hard enough. OK, so many proponents of strength training will argue this, but I counter by stating the preferential shift of blood from the muscle to the lungs when you stress the muscle adequately. The more you work the muscle (be it light weight high rep, or high weight low rep) the more the respiratory system struggles to keep up with CO2 removal. Consequently the blood preferentially shifts from your lats (or your particular target muscle) to your intercostal muscles, obliques and diaphragm…basically all the muscles that have a part to play in the breathing process.
So when you next think about letting the weight lower itself to the beginning of a rep, THINK AGAIN, this is not completing a full rep and is definitely NOT maximising your growth potential!
So next time you perform a lat pull down make sure when you come to the ‘release’ (negative) phase of the rep that you keep it slow and controlled every time. It’s no good letting the bar release quickly and freely, you need to maximise ‘time under tension’ and this is achieved by controlling the negative phase every time. How many people do you see thrusting the weight down throwing every ounce of their body weight into the movement, then letting it fly back to the starting point only to slam the breaks on at the end to stop it clattering the plates! These people (unless they are forcing reps at the end of a hard set) are getting minimal response from the muscle, the time under tension is embarrassingly low, and the physiological adaptation is not going to good. The only thing these people are increasing their chances of… is an injury!