Significance of rest time between sets?

[WannaBPowerful]

What is the significance of rest time between sets? What does it matter if you take one 30sec, one minute, or 2-3 minutes between sets except that with 2-3 minutes ul recover and lift more weight? How does this all effect and relate to muscle growth?

 

[Zyglamail]

The significance boils down to this. For the power lifter the primary concern is strength, and while for any given individual more size will equal more strength provided nothing else in their training style changes. Strength is largely derived from your bodies ability to recruit the muscle fiber you have. It is said that the average non-trained person can recruit 10% of their muscle fiber at any given time while the elite power lifter is cabale of recruiting 50%. What that means is a person can increase their strength 5x without adding any mass.....however mass is part of the equation and even develops on a PL style routine. The PL routines usually focus on development of the central nervous system and recruiting more fibers and in order to do that you have to tax the system by moving a lot of weight. To make sure your muscles are recovered enough and glycogen restored so you can lift heavy and hard on your next set longer rest periods are generally employed (ie 3-5 minutes or so). Stressing the muscles and nervous system are the primary factors in gaining strength and in order to apply maximum stress you need to let muscles replenish between sets.

For bodybuilders the primary concern is size. To acheive this you need stress (to a lesser degree than a PL) as well as fatigue. To accomplish this weights are usually a bit lower and rest periods shorter and in turn a greater hypertrophic response is acheived.

I personally feel rep count for a set (assuming 12 or less) for BBer is much less important than the rest time. I think far to many people who BB use rep range as a deciding factor on how they will progress but I for one feel fatigue is more the issue. For example a BB can do 12 rep sets and rest a couple minutes in between or do 5 rep sets and rest 30 seconds in between. In the 12 rep set you are getting fatigued due to rep quantity and in the 5 rep set you are also getting fatigued due to a shorter rest period. I personally feel, for the basic compound movements at least, that the low rep/short rest scheme is the best because in addition to the fatigue factor required for hypertrophy you are also subjecting yourself to heavier loads due to lower rep count and thus higher stress levels which has many benefits such as increasing bone density as well as tendon/ligament strength and CNS stimulation.

Just my 2cc's

 

[Mindwraith]

That so rocks Zyg, thanks for the added info on that subject.

 

[Deleted member 33117]

Zyg, another perspective on the benefits of a shorter rest time is the workload involved. Workload is not how much weight one lifts for one rep, or even the total weight moved over the course of your workout, but rather work done over a unit of time. Lets propose a simple comparison. Lets compare two bench press workouts. In both workouts, we will assume that the same form is used, and that the lifter moves the weight 1 foot per rep, taking 2 seconds per rep. Let us assume that 200 ibs is being used.
Workout #1 he takes 2 minutes between sets, enough time to get a fair amount of recovery, so he will not loss much strength from set to set
Set 1 12 reps
Set 2 11 reps
Set 3 9 reps
Total time 6 minutes 4 seconds (we'll round off at 6)

Workout #2 he takes 30 seconds between sets, so he has not recovered as much
Set 1 12 reps
Set 2 9 reps
Set 3 only 5 reps due to fatigue
Total time 1 minute 52 seconds (also rounded to 2 minutes for simplicity)
In workout #1 200 ibs was moved 32 ft in about 6 minutes
In workout #2 200 ibs was moved 26 ft in only 2 minutes
While in workout #2 only 81% as much total work was done, but it was done in 1/3 of the time that workout #2 was. In fact the workload (work done per unit of time...this would be horsepower if we were talking about your car) is about 143% higher in workout #2 than in workout #1. Which one has required the muscles involved to work harder? Clearly it is workout #2. It is the workload involved, not total work done, that stresses the muscles & forces the body to compensate...that stimulates growth. Were it the other way around, long distance runners would be sporting freakishly massive thighs and calves. If the amount of time taken to do the work is removed from the equation, and only total work done is the primary factor in stimulating growth clearly long distance running would be the ideal leg rountine. Running ten miles requires far more energy, and work done by the legs, than doing a mere 10 sets of squats. I have as of yet to see a marathon runner with 32" quads.
Perhaps this perspective sheds some light on why bodybuilders with their lighter weights, higher reps & shorter rest times have more muscle mass than many of their stronger (for a rep or two at least) power-lifter counter parts.
Just my .02

 

[Deleted member 33117]

Zyg, of course we both agree that shorter rest times will probably yield more growth stimulation. I was simply trying to give a scientific explaination of why it seems to do so that perhaps few of us have considered.