The Weider Principle of forced reps engages reaching failure on a set and then having a spotter help you get some extra reps. In order to force them to grow that is a way of pushing your muscles further than brief failure.
The research says: Finland’s study suggests that for instigating muscle growth, forced reps can be effective. The researchers had sixteen weight-trained men perform a leg work out that consisted of 4 sets of leg presses, 2 sets of leg extensions and 2 sets of squats. In one trial they performed the workout using their twelve-rep max on every exercise and performed each set until reaching muscle failure. And in another trial they used a weight slightly heavier than their twelve-rep max so that they would reach collapse before the twelfth rep, at which point a spotter helped them do forced reps until they finished twelve reps.
In the International Sports Medicine Journal, the authors reported that when the person was using forced reps, and their growth hormone levels rose about 3 times higher than when they were training just to failure. Growth hormone levels are critical for instigating muscle growth, together with encouraging fat burning. Researchers from Ashton University backed this up in a study where trained football players using forced reps in their training for ten weeks lost drastically more body fat than those not using forced reps.
How to use it: Simply take a set to muscle failure to use forced reps, and then have a spotter help you perform two to three more reps and the assistance should just be enough to let you to do the majority of the work. You can use this on the last set of each exercise in your workout. When training alone by using the non-working limb to assist the working side you can use this technique on isolation exercises.
The Pre-Exhaustion Principle
This Pre-Exhaustion Training Principle supporters training isolation or single-joint exercises first in your workout, followed by multi-joint exercises.
When you perform the following multi-joint exercise the point of pre-exhaustion is to fatigue a target muscle group so that the target muscle is already fatigued and receives plenty overload without the set ending because of fatigue of other muscle groups.
When subjects pre-exhausted their quads with leg extensions in a 2003 Swedish study found that, they had less muscle activity in the quads during the leg press. Later, Brazilian researchers reported comparable results with the chest muscles when focuses pre-exhausted with the pec deck before the bench press. And these studies support the theory as shown by the lower muscle activity, that the pre-exhaust technique weakens the target muscle, it was able to produce during the multi-joint exercise. Check out Joe Weider home gym here.
But does this method cause greater muscle growth? The answer is yes, according to a 1997 study showing that subjects using the pre-exhaustion system gained considerably more muscle mass than people using the standard training procedure of doing first multi-joint exercises and isolation exercises last.
How to use it: In order to use this method for chest, you can start your workout by doing 3 sets of a chest separation exercise like the dumbbell fly, and then 3 sets of an additional chest isolation exercise as the cable crossover. And then you can follow with multi-joint exercises such as the incline dumbbell presses and bench press, each for 3 sets.