Science-Based Weight Training
Misconceptions and wrong ideas abound in weight training, probably because so
many enthusiastic amateurs are involved in it. In this article, I’ll try to
clear up some of the misconceptions with a look at at science-based weight
training.
In recent articles, we saw that brief workouts, at 15 minutes, done
infrequently, at twice a week, can produce significant strength gains. We saw
that compound lifts, not isolation lifts, are the most effective strength
exercises, and are essential for the serious strength trainer. And we saw
that hard weight lifting causes muscle damage, which necessitates recovery
time.
Here I’ll focus on what science has to say about additional aspects of weight
lifting (resistance training). These come from “Evidence-Based Resistance
Training Recommendations” by Fisher et al.[1.Fisher, James, et al. “Evidencebased resistance training recommendations.” Med Sport 15.3 (2011): 147-162.]
(Full paper.)
Intensity of Effort
When you lift weights, muscle fibers are “recruited”, which means that as
repetitions continue and become more difficult, the body demands that more
muscle fibers come into play and perform work. At the final repetition, the
point of failure, all muscle fibers possible are recruited, and this is the
most important step in muscle growth (hypertrophy).
Recommendation: Train to momentary muscular failure in order to recruit all
possible muscle fibers. Do not train to a set number of repetitions. (For
more on this, see my article on high-intensity training.)
Load and Repetition Range
If a set of repetitions is performed to failure, it makes little to no
difference how much weight (load) you use. This comes with the caveat that
there are limits to this. For instance, if you choose a weight with which you
can do 30 reps, or 1 rep, these are unlikely to optimally recruit muscle
fibers. But otherwise, studies have found little difference on muscle
hypertrophy in lifting heavy weights (90% of max possible, or 90%RM), or
lighter weights (30%RM), so long as the lift is done to failure. However,
heavier weights (80%RM) appear to increase bone mineral density more than
lighter.
Recommendation: Select a weight of 80%RM and do reps to failure, which is
optimal for strength, muscular endurance, and bone density.
Repetition Duration
Repetition duration refers to cadence, that is, the amount of time it takes
to perform 1 rep, i.e. slow vs fast. Repetitions should be done at a slow
enough pace that muscular tension is always maintained. Fast reps or using
momentum — jerking the weights around — do not maintain muscular tension.
Recommendation: Lift slowly enough to maintain muscular tension. In extreme
cases, this may be 10 seconds up, 10 down, though that doesn’t appear to be
necessary. I use a cadence of 4-5 seconds up, same down.
Rest Intervals
This is the time spent between sets, and the preponderance of scientific
evidence shows that it has little effect on strength gains.
For pure muscle growth, don’t worry about rest intervals. Take as much or as
little time as you like.
However, rest intervals may make a difference to cardiovascular conditioning.
If you want to emphasize the cardiovascular aspect of training, short rest
intervals are better.
Recommendation: Select your own rest interval for muscle growth. Use short
rest intervals for cardiovascular conditioning.
Volume and Frequency
These refer to the number of sets and the frequency of training sessions, and
this area shows probably the greatest disparity between what most people,
including veteran lifters, believe, and what the science says.
There’s little evidence that performing more than 1 set of each exercise
increases muscle growth, if that 1 set is done to failure.
There’s little evidence to support any recommendation as to frequency. Some
studies have reported no difference with a training frequency of once vs
twice a week, other studies showing no difference between twice or three
times a week. My own experience tells me that you can train so long as you
feel fully rested and recovered.
Recommendation: Single set training appears to be as effective as multiple
sets for muscle growth. There’s little scientific evidence for a
recommendation as to frequency of training.
Endurance Training and Lifting
Some people worry that doing endurance training might hinder their lifting
gains. There’s no evidence that it does, so do endurance training also if
that’s what you want to do. However, additional training may hinder recovery
time.
Recommendation: Endurance training doesn’t hinder muscle growth.
Range of Motion
Most trainers recommend you use a full range of motion for each rep in order
to get the most growth. But there’s no evidence for this. A restricted range
of motion appears to increase strength and size as much as full range.
Recommendation: Use any range of motion you like.
Machines vs Free Weights
Another controversial area. Evidence directly comparing the two is meager,
but machines do increase size and strength. A muscle doesn’t know whether
you’re using a machine or a barbell.
Machines may make it easier to perform a lift to failure. For instance,
trying to go to failure on a set of squats is asking for trouble, namely
injury. Not a problem to do so on a leg press or hack squat machine.
Just about the only barbell exercise that I’m aware of that has no machine
equivalent is the deadlift.
Recommendation: Use either machines or free weights as you wish.
Training and Detraining
A mere 3 weeks of training is enough to produce muscle growth in untrained
people.
Of more interest, how long does it take, when no training is done, to lose
muscle strength?
Again, 3 weeks of no training appears to have little to no effect on muscle
strength. Most dedicated lifters don’t ever take that much time off, but this
shows that allowing adequate rest between training sessions, even of
considerable length, will not hurt gains.
Recommendation: If you feel the need to take some time off, or just can’t
manage to get to the gym for awhile, don’t worry about it.
Conclusion
Many of these recommendations are to a greater or lesser extent at odds with
common training methods, the kind that you hear from a trainer or gym bro.
It’s entirely possible that scientific studies miss some important aspects of
training that come from years of bodybuilding experience. Resistance training
studies normally last only about 12 weeks, and most have been done using
untrained people.
But, when science looks at techniques, muscle protein synthesis, frequency of
training, and the like, these are the conclusions, and they form our base of
knowledge as it relates to weight training.
If I had to pick a single one of the above recommendations to emphasize, it
would be intensity of effort, which appears to be the single most important
aspect in attaining growth in strength and size.
PS: For much more on the health benefits of strength training as
well as how to begin a training program, see my book Muscle Up.
PPS: Check out my Supplements Buying Guide for Men.
Subscribe and get my free book on fat loss