PRINCIPLES OF MUSCULAR TRAINING
To have a good exercise program, the seven principles of exercise,
described in Chapter 1, must be applied to all muscular endurance
and strength training. These principles are overload, progression,
specificity, regularity, recovery, balance, and variety.
The overload principle is the basis for all exercise training
programs. For a muscle to increase in strength, the workload to
which it is subjected during exercise must be increased beyond
what it normally experiences. In other words, the muscle must
be overloaded. Muscles adapt to increased workloads by becoming
larger and stronger and by developing greater endurance.
To understand the principle of overload, it is important to know the following strength-training terms:
- Full range of motion. To obtain optimal gains, the overload
must be applied throughout the full range of motion. Exercise
a joint and its associated muscles through its complete range
starting from the pre-stretched position (stretched past the relaxed
position) and ending in a fully contracted position. This is crucial
to strength development.
- Repetition. When an exercise has progressed through one complete
range of motion and back to the beginning, one repetition has
- One-repetition maximum (1-RM). This is a repetition performed
against the greatest possible resistance (the maximum weight a
person can lift one time). A 10-RM is the maximum weight one can
lift correctly 10 times. Similarly, an 8-12 RM is that weight
which allows a person to do from 8 to 12 correct repetitions.
The intensity for muscular endurance and strength training is
often expressed as a percentage of. the 1-RM.
- Set. This is a series of repetitions done without rest.
- Muscle Failure. This is the inability of a person to do another correct repetition in a set.
When a muscle is overloaded by isometric, isotonic, or isokinetic contractions, it adapts by becoming stronger.
The minimum resistance needed to obtain strength gains is
50 percent of the 1-RM. However, to achieve enough overload, programs
are designed to require sets with 70 to 80 percent of one's 1-RM.
(For example, if a soldier's 1-RM is 200 pounds, multiply 200
pounds by 70 percent [200 X 0.70 = 140 pounds] to get 70 percent
of the 1-RM.)
A better and easier method is the repetition maximum (RM)
method. The exerciser finds and uses that weight which lets him
do the correct number of repetitions. For example, to develop
both muscle endurance and strength, a soldier should choose a
weight for each exercise which lets him do 8 to 12 repetitions
to muscle failure. The weight should be heavy enough so that, after doing from 8 to 12 repetitions, he momentarily
cannot correctly do another repetition. This weight is the 8-12
RM for that exercise.
|FITT Factors Applied to Physical Conditioning Programs for Muscular Endurance and/or Strength
||Muscular Strength and Muscular Endurance
||3 times per week
||3 - 5 times per week
||3 times per week
||3 - 7 RM*
||8 - 12 RM
||The time required to do 3 - 7 repetitions of each resistance exercise
||The time required to do 12+ repetitions of each resistance exercise
||The time required to do 8 - 12 repetitions of each resistance exercise
Body-Weight Exercises (Push-ups/Sit-ups/Pull-ups/Dips, etc.)
|*RM - Repetition Maximum
MUSCULAR ENDURANCE/STRENGTH DEVELOPMENT
To develop muscle strength, the weight selected should be heavier and the RM will
also be different. For example, the exerciser should find that weight
for each exercise which lets him do 3 to 7 repetitions correctly.
This weight is the 3-7 RM for that exercise. Although the greatest
improvements seem to come from resistances of about 6-RM, an effective
range is a 3-7 RM. The weight should be heavy enough so that an
eighth repetition would be impossible because of muscle fatigue.
The weight should also not be too heavy. If one cannot do
at least three repetitions of an exercise, the resistance is too
great and should be reduced. Traniners who are just beginning a
resistance-training program should not start with heavy weights.
They should first build an adequate foundation by training with
an 8-12 RM or a 12+ RM.
To develop muscular endurance, the trainer should choose a
resistance that lets him do more than 12 repetitions of a given
exercise. This is his 12+ repetition maximum (12+ RM). With continued
training, the greater the number of repetitions per set, the greater
will be the improvement in muscle endurance and the smaller the
gains in strength. For example, when a lifter trains with a 25-RM
weight, gains in muscular endurance will be greater than when
using a 15-RM weight, but the gain in strength will not be as
Whichever RM range is selected, the trainer must always strive
to over-load his muscles. The key to overloading a muscle is to
make that muscle exercise harder than it normally does.
An overload may be achieved by any of the following methods:
- Increasing the resistance.
- Increasing the number of repetitions per set.
- Increasing the number of sets.
- Reducing the rest time between sets.
- Increasing the speed of movement in the concentric phase. (Good form is more important than the speed of movement.)
- Using any combination of the above.
When an overload is applied to a muscle, it adapts by becoming
stronger and/or by improving its endurance. Usually significant
increases in strength can be made in three to four weeks of proper
training depending on the individual. If the workload is not progressively
increased to keep pace with newly won strength, there will be
no further gains. When a lifter can correctly do the upper limit
of repetitions for the set without reaching muscle failure, it
is usually time to increase the resistance. For most people,
this upper limit should be 12 repetitions.
For example, if his plan is to do 12 repetitions in the bench
press, the exerciser starts with a weight that causes muscle failure
at between 8 and 12 repetitions (8-12 RM). He should continue
with that weight until he can do 12 repetitions correctly. He then should increase the
weight by about 5 percent but no more than 10 percent. In a multi-set
routine, if his goal is to do three sets of eight repetitions
of an exercise, he starts with a weight that causes muscle failure
before he completes the eighth repetition in one or more of the
sets. He continues to work with that weight until he can complete
all eight repetitions in each set, then increases the resistance
by no more than 10 percent.
A resistance-training program should provide resistance to
the specific muscle groups that need to be strengthened. These
groups can be identified by doing a simple assessment. The exerciser
slowly does work-related movements he wants to improve and, at
the same time, he feels the muscles on each side of the joints
where motion occurs. Those muscles that are contracting or becoming
tense during the movement are the muscle groups involved. If the
person's performance of a task is not adequate or if he wishes
to improve, strength training for the identified muscle(s) will
be beneficial. To improve his muscular endurance and strength.
in a given task, the trainer must do resistance movements that
are as similar as possible to those of doing the task.
Exercise must be done regularly to produce a training effect. Sporadic exercise may do more harm than good.
One can maintain a moderate level of strength by doing proper strength workouts only once a week, but three workouts per week are best for optimal gains.
The principle of regularity also applies to the exercises
for individual muscle groups. A person can work out three times
a week, but when different muscle groups are exercised at each
workout, the principle of regularity is violated and gains in
strength are minimal.
Consecutive days of hard resistance training for the same
muscle group can be detrimental. The muscles must be allowed sufficient
recovery time to adapt. Strength training can be done every day
only if the exercised muscle groups are rotated, so that the same
muscle or muscle group is not exercised on consecutive days. There should be at least a 48-hour recovery period between workouts
for the same muscle groups. For example, the legs
can be trained with weights on Monday, Wednesday, and Friday and
the upper body muscles on Tuesday, Thursday, and Saturday.
There should be at least a 48-hour recovery period between workouts for the same muscle group.
Recovery is also important within a workout. The recovery
time between different exercises and sets depends, in part, on
the intensity of the workout. Normally, the recovery time between
sets should be 30 to 180 seconds.
When developing a strength training program, it is important
to include exercises that work all the major muscle groups in
both the upper and lower body. One should not work just the upper
body, thinking that running will strengthen the legs.
It is important to include exercises that work all the major muscle groups in both the upper and lower body.
Most muscles are organized into opposing pairs. Activating
one muscle results in a pulling motion, while activating the opposing
muscle results in the opposite, or pushing, movement. When planning
a training session, it is best to follow a pushing exercise with
a pulling exercise which results in movement at the same joint(s).
For example, follow an overhead press with a lat pull-down exercise.
This technique helps ensure good strength balance between opposing
muscle groups which may, in turn, reduce the risk of injury. Sequence
the program to exercise the larger muscle groups first, then the
smaller muscles. For example, the lat pull-down stresses both
the larger latissimus dorsi muscle of the back and the smaller
biceps muscles of the arm. If curls are done first, the smaller
muscle group will be exhausted and too weak to handle the resistance
needed for the lat pull-down. As a result, the trainer cannot
do as many repetitions with as much weight as he normally could
in the lat pull-down. The latissimus dorsi muscles will not be
overloaded and, as a result, they may not benefit very much from
The best sequence to follow for a total-body strength workout
is to first exercise the muscles of the hips and legs, followed
by the muscles of the upper back and chest, then the arms, abdominal,
low back, and neck. As long as all muscle groups are exercised
at the proper intensity, improvement will occur.
A major challenge for all fitness training programs is maintaining
enthusiasm and interest. A poorly designed strength-training
program can be very boring. Using different equipment, changing
the exercises, and altering the volume and intensity are good
ways to add variety, and they may also produce better results.
The trainer should periodically substitute different exercises
for a given muscle group(s). For example, he can do squats with
a barbell instead of leg presses on a weight machine.