Numerous university studies have found that the optimal amount of weight a person should use is between 65% and 80% of what is called One Repetition Maximum. Other studies have found that “maximum hypertrophy occurs with loads from 80-95% 1RM.”
The One Repetition Maximum is the maximum weight a person can lift one time. It is often referred to as One Rep Max or RM.
Trying to determine your RM by actually going into the gym and seeing how much weight you can move on a single repetition is a hazardous thing that few people actually recommend. The safer approach is to use a Rep Max calculator.
The calculators are not perfect, but they are close enough to effective.
In Megan’s case she could do 55 pounds for four reps. By standard calculations, she could lift 60 pounds one time.
For maximum benefit she should try to work with 80% of her Rep Max, which is 48 pounds. Since most dumbbells move in five pound increments, Megan should use 45 or 50 pound dumbbells.
Using heavier weights leads to muscle hypertrophy which increases muscle tone and stimulates the metabolism to burn more calories.
Heavy weightlifting cranks up the metabolism by redirecting calories into repairing muscle and building just a little bit more which is why weight lifting is so effective for losing fat.
MASTERING METABOLIC MUSCLE
Lifting weights at around 80% of Rep Max creates what professional fitness competitor Nita Marquez calls the triple threat of fat loss.
A person lifting weights is obviously burning calories during their workout.
If they are lifting heavy enough to stimulte hypertrophy, they will be burning calories long after the workout is done as their muscles repair from the micro-trauma, the itty-bitty tears and pulls, caused by the heavy weights.
The little bit of extra muscle built from the heavy weight lifting also burns a few extra calories a day.
The process works like this: Presume you have “M” amount of muscle on your biceps. You do two or three sets of heavy arm curls which inflicts some micro-trauma on the muscles. Over the course of the next few days the body has to use extra calories to repair the muscle to its original state and will add just a little bit more.
Expressed in a series formula it might look like this:
M, M-.5, M, M+.1
The repair the muscle and increase muscle tone and size burns as many calories as the actual workout.
If a person is not using heavy enough weights to inflict significant micro-trauma and stimulate hypertrophy, the only calories burned are from the workout itself.
When Megan was using 35-pound dumbells, she was only working at 58% of her Rep Max which the studies show is usually not enough to get the benefits of weight lifting. She burned calories during the workout, but not very many after the workout.
To get the maximum benefit from your workout use weights around 80% of your One Rep Maximum. Most people can lift more weight than they think and once they start, the results can be amazing.
Of course, if your current regime consists of high repetitions with 12 (fluid) once weights, this may not be your chief concern.
via Glenn Reynolds