RESEARCH UPDATE: Muscle Growth
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"Does aerobic exercise really slow down muscle growth?"
Many people are concerned that adding aerobic exercise to their
weight-training program will slow down muscle growth.
However, new research shows that strength training and aerobic
exercise performed concurrently for 10 weeks won't interfere
with gains in muscle size and strength.
To examine the effect of aerobic exercise and strength training
performed concurrently on the rate of muscle growth, researchers
assigned a group of 30 healthy (but untrained) male subjects to
one of three groups.
* Group one performed high-intensity strength training for three
days each week. The program involved eight exercises, with
four sets of 5-7 repetitions being completed for each exercise.
The first set served as a warm-up. Subsequent sets were taken
to the point of muscular failure. Subjects rested for 60-90
seconds between sets.
* Group two completed three sessions of moderate-intensity
aerobic exercise each week. Each workout lasted 50 minutes.
* Subjects in group three combined aerobic exercise and strength
training. Both workouts were performed on the same day, with
the order of strength and aerobic exercise rotated each
training day. Subjects rested for 10-20 minutes between
workouts.
Muscle strength and size were measured before and after the
program. The researchers also measured the size of individual
muscle fibers in the thighs. As you can see in the table below,
combining aerobic exercise and high-intensity strength training
didn't impair muscle growth.
Strength Group
- Quadriceps size + 12%
- Type II Fiber Size + 24%
Endurance Group
- Quadriceps size + 3%
- Type II Fiber Size + 4.5%
Combined Group
- Quadriceps size + 14%
- Type II Fiber Size + 28%
Gains in muscle strength, however, were slightly lower in the
combined group compared to the strength training group (7% and
12%, respectively).
These findings do suggest that aerobic exercise and strength
training performed concurrently for 10 weeks won't interfere
with muscle growth. However, there are several important points
about this study that you need to consider.
Firstly, although the test subjects were healthy, they were
untrained. Beginners usually show some kind of gain in muscle
size and/or strength no matter what type of program they follow.
If you have several years of training under your belt, and you're
following a split routine that involves training with weights
5-6 days each week, there's a good chance that aerobic exercise
will impair gains in strength and size.
Moreover, although aerobic exercise is usually added to a
program in order to speed up fat loss, the majority of research
shows that aerobic exercise as it's traditionally performed has
very little effect on the rate at which you lose fat.
A properly designed weight training program, combined with
interval exercise, is far more effective at promoting fat loss,
while also preventing the loss of lean muscle tissue that often
occurs during a low-calorie diet.
Reference
McCarthy, J.P., Pozniak, M.A., & Agre, J.C. (2002).
Neuromuscular adaptations to concurrent strength and endurance
training. Medicine and Science in Sports and Exercise, 16,
152-156
To view this update on-line, visit:
---------------------------------
"Does aerobic exercise really slow down muscle growth?"
Many people are concerned that adding aerobic exercise to their
weight-training program will slow down muscle growth.
However, new research shows that strength training and aerobic
exercise performed concurrently for 10 weeks won't interfere
with gains in muscle size and strength.
To examine the effect of aerobic exercise and strength training
performed concurrently on the rate of muscle growth, researchers
assigned a group of 30 healthy (but untrained) male subjects to
one of three groups.
* Group one performed high-intensity strength training for three
days each week. The program involved eight exercises, with
four sets of 5-7 repetitions being completed for each exercise.
The first set served as a warm-up. Subsequent sets were taken
to the point of muscular failure. Subjects rested for 60-90
seconds between sets.
* Group two completed three sessions of moderate-intensity
aerobic exercise each week. Each workout lasted 50 minutes.
* Subjects in group three combined aerobic exercise and strength
training. Both workouts were performed on the same day, with
the order of strength and aerobic exercise rotated each
training day. Subjects rested for 10-20 minutes between
workouts.
Muscle strength and size were measured before and after the
program. The researchers also measured the size of individual
muscle fibers in the thighs. As you can see in the table below,
combining aerobic exercise and high-intensity strength training
didn't impair muscle growth.
Strength Group
- Quadriceps size + 12%
- Type II Fiber Size + 24%
Endurance Group
- Quadriceps size + 3%
- Type II Fiber Size + 4.5%
Combined Group
- Quadriceps size + 14%
- Type II Fiber Size + 28%
Gains in muscle strength, however, were slightly lower in the
combined group compared to the strength training group (7% and
12%, respectively).
These findings do suggest that aerobic exercise and strength
training performed concurrently for 10 weeks won't interfere
with muscle growth. However, there are several important points
about this study that you need to consider.
Firstly, although the test subjects were healthy, they were
untrained. Beginners usually show some kind of gain in muscle
size and/or strength no matter what type of program they follow.
If you have several years of training under your belt, and you're
following a split routine that involves training with weights
5-6 days each week, there's a good chance that aerobic exercise
will impair gains in strength and size.
Moreover, although aerobic exercise is usually added to a
program in order to speed up fat loss, the majority of research
shows that aerobic exercise as it's traditionally performed has
very little effect on the rate at which you lose fat.
A properly designed weight training program, combined with
interval exercise, is far more effective at promoting fat loss,
while also preventing the loss of lean muscle tissue that often
occurs during a low-calorie diet.
Reference
McCarthy, J.P., Pozniak, M.A., & Agre, J.C. (2002).
Neuromuscular adaptations to concurrent strength and endurance
training. Medicine and Science in Sports and Exercise, 16,
152-156
To view this update on-line, visit: