Determinants of Muscle Size

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Apart from muscle fiber type, various factors influence muscle size (see Figure 7-1). Although some factors cannot be controlled, two factors that we can control are exercise and nutrition habits (Chapters 3, 4, and 11).


Physical Activity



Nervous System Activation

Hormones i

Adapted from WD McArdle, FI Katch, and VL Katch. Exercise Physiology, 4th ed. Baltimore; Williams & Wilkins, 1996.

Men generally have more muscle mass than women, mainly because men produce more testosterone than women. Strength training may increase muscle mass slightly in women; however, a common misconception is that strength training will cause women to "bulk up." Importantly, strength training will greatly increase muscle strength and endurance and reduce the risks for injury. Moreover, women tend to have poor upper body strength and many military tasks require upper body strength.

Strength Training Guidelines

Training Form

Correct lifting techniques are critical for achieving maximum benefits and preventing injury (see Appendix C). If your form is incorrect, strength training can lead to injury, not strength gains.

  • When learning a new exercise, start with minimal weight.
  • Use a closed grip (fingers and thumbs wrap around the bar or handle and touch each other), and place hands equidistant from the ends of the bar. Load the weights evenly across the bar.
  • For free weights, feet should be hip to shoulder width apart, knees slightly bent, and your back should keep its natural curve. Keep your head level and eyes focused straight ahead. If maintaining this posture is difficult than the weight is too heavy.
  • If using resistance machines, adjust the pads to fit your body size. This is very important since the pads support you during the lift. Keep your head level and eyes focused straight ahead.
  • Lifts should be slow, smooth, and controlled. Lift the weight for at least 2 seconds and lower the weight for at least 4 seconds to ensure that your muscle, not momentum, moves the weight.
  • Exhale during the exertion (moving the weight against gravity), and inhale when returning to the start position. Holding your breath (Valsalva maneuver) causes extremely high increases in blood pressure and can damage the cardiovascular system. Never hold your breath while exercising!
  • Always use a spotter when lifting free weights.

The most common training errors occur when people focus on lifting the weight rather than focusing on stabilizing themselves and controlling the weight. The best way to avoid training mistakes is to ask a staff member at the gym to teach you new exercises and to suggest the best exercises for you based on your fitness level and goals. See Appendix C for examples of common errors in training techniques.

FITT Principle Guidelines

Once you are comfortable with the basic training techniques for performing strength exercises, follow the FITT Principle, illustrated in the Physical Activity Pyramid (Chapter 4, Figure 4-2), to set up your routine. The FITT guidelines for strength training are:

  • Frequency - 2 to 3 times per week for each major muscle group on non-consecutive days.
  • Intensity - the total weight lifted or the resistance.
  • Time - the duration of the exercise.
  • Type - equipment used and the exercises performed.

Two terms you need to know are repetition (rep) and set. A repetition is a single lifting and lowering of the weight. For example, one rep of a leg curl is equivalent to lifting your ankle toward your buttocks, pausing one second, then returning your ankle to the start position. A set is the number of reps performed without stopping to rest. For example, if you perform 10 leg curls, rest for 60 seconds, followed by another 10 leg curls, you would have performed 2 sets, each of 10 leg curls. When recording the number of sets and reps performed, write "sets x reps" (e.g., 2x10 for the leg curl example above).

Intensity of Exercise

Focus on the intensity of your training only after you have perfected your lifting form. The basis of strength training is to gradually increase the amount of weight that you lift during training to ultimately increase the amount of force your muscles are capable of generating. This is called progressively overloading the muscle to achieve gains in strength without causing injury. The following intensity guidelines for general strength gains are for beginners, for people who are restarting their routines after a break, or for people learning new exercises.

  • Once your form is perfected (page 58), gradually increase the weight you are lifting until you reach a weight that you can lift only 12 times with good form. If you can perform 13 or more reps with relative ease, increase the weight. Conversely, if you cannot perform 12 reps while maintaining proper form, decrease the weight. Finding this 12-rep weight will be trial and error at first. Be patient and gradually increase the weight to avoid straining or injuring yourself.
  • Your 12-rep weight will increase as you gain strength, so increase the weight you are lifting appropriately (by no more than 10% per week).
  • Start a training routine consisting of one to two sets of 12 reps for each major muscle group (defined in "Type of Exercise" on page 61). Perform this routine for at least eight weeks.

A long-term strength routine of one to two sets of 12 reps is excellent for maintaining and increasing general strength, even beyond the first eight weeks of training. In addition, this type of routine only takes roughly 30 minutes to perform. Once you have developed a solid strength and endurance base you may be interested in pursuing more specific training goals. In general, the following guidelines apply to the various types of strength training goals:

  • Muscle endurance - two to three sets, 12-15 reps (with a weight that cannot be lifted more than 15 times); 30-60 seconds rest between sets.
  • Muscle hypertrophy (increase in muscle mass) - three to six sets, eight to 12 reps (with a weight that cannot be lifted more than 12 times); 30-90 seconds rest between sets.
  • Muscle strength - three to five sets, two to eight reps (with a weight that cannot be lifted more than eight times); at least 120 seconds rest between sets.

Note: Do not perform maximal lifts when strength training.

Type of Exercise

Muscle balance refers to the strength ratio of opposing muscle groups across a common joint; i.e., the biceps and triceps muscles in the upper arm. By performing exercises that target the opposing muscle groups across the joints, you improve the function of the joints and reduce your risks for injury. With this in mind, select at least one exercise for each of the major muscle groups. The major muscle groups are the chest, back, shoulders, arms, legs, lower back, and abdominals. (See Worksheet B-2.)

From Harmon, E. The biomechanics of resistance exercise. In Essentials of Strength Training and Conditioning. Baechle, TR. (Ed.). Human Kinetics. Champaign, Il. 1994. p.20.

With respect to exercise order, perform multi-joint n exercises (e.g., squats) before single-joint exercises (e.g., leg curl). To determine which exercises are multi- versus /^W^lZL in single joint exercises, watch and feel how many joints ff^ W

move while you perform the exercise. An example of a ¿5 multi-joint exercise is the bench press because your Bench Press Arm Cur|

upper and lower arms move at the shoulder and elbow joints, respectively. An example of a single-joint exercise is a biceps curl because only your lower arm moves at the elbow. Single-joint exercises target and fatigue the smaller muscle groups that are needed to perform multi-joint exercises. Therefore, fatiguing the smaller muscle groups by first performing single-joint exercises will alter your lifting form and decrease the amount of weight you can lift in the multi-joint exercises. Lastly, lower back and abdominal exercises should be performed at the end of your workout because these muscles are used during other exercises for balance and posture. Figure 7-2 is a diagram of the muscle groups and the exercises that target them. Pick at least one exercise per major muscle group.

From Harmon, E. The biomechanics of resistance exercise. In Essentials of Strength Training and Conditioning. Baechle, TR. (Ed.). Human Kinetics. Champaign, Il. 1994. p.20.

Ci to



shrug, pull-ups, rows

(Deltoid, Rotator Cuff)

lateral raise, upright row shoulder press, bench press, reverse fly, rotations

Triceps triceps extensions, dip, push-up bench presses, kickback


(Latissimus Dorsi, Lats) lat pulldown, pullover, rows pull-up

Low Back

(Erector Spinae)

back extension, superman

  • Forearm
  • wrist extensors)

reverse wrist curls

Gluteals leg press, lunge, squats, hip extension, glute-ham raise rear thigh raise

Hamstring leg curl, leg press, squats lunge, glute-ham raise


(Gastrocnemius & Soleus) calf raise, heel raises, lunge


/ (Pectorals) bench presses, chest fly, dip chest press, push-up

Curls (arm, preacher, hammer concentration), chin-up, rows lat pulldown


(Rectus Abdominus and Obliques) crunches, knee raises, rotary torso


(wrist flexors)

wrist curls

Outer Thigh

(hip abductors) hip abduction, leg raises

Quadriceps leg extension, leg press, squats, lunge, step ups

Inner Thigh

(hip adductors)

hip adduction, leg raises


(Tibialis Anterior)

toe raises, foot flexion with resistance




Use Worksheet B-2 as a template to design your workout and to record your training progress. Change the exercises you perform for each muscle group every four to eight weeks, even if you keep the same set and rep routine. Changing exercises will overload the muscles differently, increase your strength gains, and alleviate boredom. To increase their upper body strength, women should perform exercises that target the back, neck, chest, shoulders and arms (Figure 7-2).


Strength training requires minimal personal gear: weights, a pair of supportive shoes, fitted lifting gloves, and standard PT attire. A weight lifting belt is only recommended during maximal or near maximal lifts, and is not recommended at all for exercises that do not stress the back. This is because the belt takes over the role of the abdominal muscles in stabilizing the torso, preventing the strengthening of the abdominal muscles which can increase the risk for injury when lifting a heavy object without the belt.

The most common barbells found in gyms are Olympic style barbells. These barbells have a narrow center bar for gripping and wider ends for loading weights. They are 5 to 7 ft. long and weigh 30 to 45 pounds (lbs) or 13 to 20 kilograms (kg). The plates used to load the bars are available in both lbs and kg, and range between 2.5 to 45 lbs or 1.25 to 20 kg. Make sure you pay attention to the weight measurements in your gym; there is a big difference between 10 lbs and 10 kg! Lastly, you are encouraged to use adjustable collars to keep the plates on the bar. Depending on the style of collar, the pair can add 1 to 5 lbs to your bar. There are several other styles of barbells which range in size and weight. Ask a staff member at your gym to help you determine which barbell would best suit your needs.

Choosing free weights, machines, or a combination of both depends largely on your goals and training experience. Table 7-2 lists a comparison of free weights and machines to help you with your choice. If you are new to a fitness center or if you are unsure how to work a piece of equipment, ask a fitness center staffer for an orientation. This orientation will help you design a workout routine based on the equipment selection at your fitness center.

Table 7-2. Free Weights vs. Resistance Machines

Free Weights

Low cost and versatile.

Form is crucial; spotter is needed.

Trains balance and posture; mimics daily activities.

Can perform multi-joint and single-joint exercises.

Muscles trained through joint's full range of motion.

Resistance Machines

Expensive, less versatile, need access to equipment.

Supports the body during the exercise; easy to adjust.

Isolates muscle groups more easily than free weights.

Machines made for multi-joint and single-joint exercises.

Muscle training occurs in a limited range of motion.

Though this chapter focuses on resistance machines and free weights, resistance for strength training can come from a variety of sources, including your own body weight. To learn about other exercise techniques and equipment available for strength training see Chapters 8 and 10. These other options may be most beneficial when space and equipment are limited.

Types of Workouts

Following is a description of several strength training routines. Choose the routine that is best for you based on the time available, your goals, your training experience, and your fitness level.

  • Full body workouts - All the major muscle groups (as listed in Worksheet B-2) are exercised during a single session. Perform one to two sets of an exercise for each muscle group and rest between sets. This should take 20-45 minutes. For general strength training purposes; should be done at least twice a week.
  • Circuit Training - Combines aerobic and strength exercise stations. Each exercise station takes 30-45 seconds to perform and stations alternate between upper and lower body exercises. The circuit is repeated two or more times per session. It improves aerobic conditioning and moderately increases strength when performed three times per week. This routine is good for people who have less than 45 minutes to do both aerobic and strength exercises. (See Table 10-2 for an example.)

The following routines are more advanced workouts. They should only be performed once you have developed a solid strength base using one of the above formats, and you have exercised regularly for at least eight weeks, and are comfortable with the correct lifting techniques.

  • Split-routine workouts - Different muscle groups are targeted on alternate training days. Examples include: upper versus lower body, or push (e.g., chest press, leg extension) versus pull (e.g., seated row, leg curl) exercises. Allows for more intense training for each muscle group per training session; is time consuming.
  • Pyramid sets - Successive sets of the same exercise are performed with progressively greater resistance while decreasing the number of reps. For example: perform 10 reps with a 10-rep weight in set 1; perform eight reps with an eight-rep weight in set 2; perform six reps with a six-rep weight in set 3. Rest between sets. You can mix up the number of sets and reps per set that are performed. Allows for a varied training intensity, but is more time consuming than performing one set per exercise per muscle group.
  • Super sets - Performing two exercises for opposing muscle groups without a rest period between sets. Example: a set of a chest exercise immediately followed by a set of a back exercise, followed by a rest. This combination can be repeated one to two more times. Limit this type of workout to once a week; on the remaining workout days, rest between each set. May be useful for muscle hypertrophy.
  • Compound sets - Performing two exercises for the same muscle group without a rest period between sets. Example: a set of one chest exercise immediately followed by a set of a different chest exercise, followed by a rest. Repeat this combination one to two more times. Limit this type of workout to once a week; on the remaining workout days, rest between each set. May be useful for muscle hypertrophy.

Use the guidelines provided to develop sound strength training programs and alternate exercises with in each muscle group every four to eight weeks to maximize strength gains, enhance job-related fitness, and have fun!


In this chapter you will learn about:

  • Proper form and guidelines for performing calisthenics.
  • Designing a calisthenic exercise program.
  • Abdominal exercise techniques.

Calisthenics require minimal equipment and can be performed in almost any location. These exercises can be used to develop and maintain muscle strength and muscle endurance, and can be particularly useful when strength training equipment is not available.

Muscle Balance

As discussed in Chapter 7, muscle balance is an important consideration when designing any strength workouts. Exercises should be selected according to which muscle groups they target (Table 7-2). Table 8-1 lists several calisthenic exercises and the muscle groups they target. Use this table to design your calisthenic routine. Also, you can add any of these exercises to your gym-based strength and endurance routines to create variety and alleviate boredom.

Calisthenic Guidelines

When performing calisthenics to develop muscle strength or endurance, you should follow the same recommendations outlined in Chapter 7. Intensity is largely based on the number of sets and reps, and the length of rest periods. Resistance is provided by body weight rather than an external resistance. Proper form for calisthenic exercises follows many of the general exercise guidelines outlined in Chapter 7. Detailed instructions are found in Table 8-1. (Table 8-1 was adapted from The Navy SEAL Physical Fitness Guide.)

To begin a calisthenics program select one exercise per muscle group from Table 8-1. Perform this routine two to three times per week.

  • For each exercise, start with one set of eight reps. Each set should take about one minute. Rest for 60 seconds after each set.
  • Gradually increase your workout by adding one or two reps per week until you can perform twelve reps with good form.
  • Once you have reached this point, do two sets of eight reps of each exercise. Again, increase your workout by one or two reps per set each week until you can perform two sets of twelve reps.
  • Once you have reached this point, do three sets of eight reps; again, gradually increase your workout by one or two reps per set each week until you can do three sets of twelve reps.
  • At this point you can increase the difficulty of your workout by: 1) changing the exercises you perform; 2) increasing the number of reps per set; 3) modifying the difficulty of the exercise; 4) decreasing your rest period; or 5) for each muscle group, do a different exercise during each one of your sets (for example, do one set of one-legged squats and one set of hand-to-knee squats as your two sets of leg exercises).

Once you can perform three sets of 12 reps, try some of the modifications listed below or in Table 8-1 to increase the difficulty of the exercises. These modifications can be useful for developing and maintaining muscle strength when training equipment is not available.

  • Gradually add weight (e.g., do pull-ups or push-ups with a weighted pack).
  • Use a partner for resistance (e.g., have a partner push against your lower leg during leg extensions).
  • Exercise one side of the body first (i.e., one-legged squats), then repeat the exercises for the other side.
  • Modify the exercise (e.g., elevate legs during crunches).
  • Perform super sets or pyramids (see Chapter 7).



Lie on stomach, feet and hands shoulder width apart on deck, head facing forward, body straight. Extend arms. Count 1: Bend elbows 90o, lowering chest toward deck. Count 2: Return to start position. Works triceps, chest, shoulder, and abdominals. Variations: Fingertip Push-ups - Begin as above, except use fingertips to support weight. Works forearms and improves grip strength. Triceps Push-ups - Begin as above, except place your hands close together beneath your chest and spread fingers apart. Your thumbs and index fingers of both hands should almost touch.


Rest hands on parallel bars. Extend arms; legs are not to support your weight unless needed for assistance. Count 1: Bend the elbows until shoulders are level with the elbows. Count 2: Extend arms to return to start position. Works triceps, chest and shoulders.


Begin from a dead hang on a horizontal bar, arms shoulder-width apart, palms facing out. Count 1: Pull body up until chin touches bar. Do not kick. Count 2: Return to start position. Works the back and forearms. Grip variations: Narrow, Wide.

Incline Pull-Ups

Using a low bar, lie or sit on the deck with chest under bar, place hands shoulder-width apart on bar, palms out. Count 1: Pull upper body toward bar at a 45° angle. Squeeze shoulder blades together during movement. Count 2: Extend arms. Works back, shoulders, and arms.


Begin from a dead hang (i.e., full extension) on a horizontal bar, arms shoulder-width apart, palms facing in. Count 1: Pull body upward until chin touches top of bar. Do not kick. Count 2: Return to start position. Works the back, biceps.

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Neck Rotations

Lie on back. Count 1: Lift head up and over to side. Count 2: Bring head to center; Count 3: Bring head to other side. Count 4: Return head to start position. Works neck flexors.

Straight Leg Raise

Sit on the edge of a bench, keeping back straight. Place hands behind you for support. Bend left knee 90o. Straighten right leg in front of you with your right heel resting on the deck. Count 1: Slowly raise your right leg, lifting it no higher than your hips, keeping your back straight. Count 2: Lower heel to 1 inch above the deck. Works hip flexors. Variation to increase difficulty: use an ankle weight.

CD r


05 CD


Lie on back, knees bent 90o, feet on deck, hands behind head, elbows back. Count 1: Lift upper torso until shoulder blades are off the deck, tilt pelvis so lower back is pressed to the deck. Lead with the chest, not the head. Count 2: Return to start position. Works abdominals and obliques. Variations to increase difficulty: bend legs and bring knees toward chest; extend legs vertically, straight in the air; or place a rolled towel under lower back. Arms may be placed (easy to most difficult) alongside body, across chest, hands behind head, or hands clasped above head.


Lie on back, hands behind head, knees bent 90°, and feet on deck. Count 1: Turn slightly and lift torso, bringing left rib cage toward belly button. Count 2: Return to start position. Repeat on other side. Works abdominals and obliques.

Hip Rollers

Lie on back, legs bent and elevated off deck. Count 1: Slowly bring both knees down together to the right until lower back begins to rise off deck. Count 2: Return to start position. Works abdominals and obliques.


Lie on stomach. Count 1: Lift opposite arm and leg (i.e., right arm, left leg) 6 inches off deck. Hold for 35 seconds. Avoid hyperextension of the back. Count 2: Slowly lower arm and leg to deck. Repeat using opposite arm and leg. Variation to increase difficulty: Add weights to arms and legs. Works lower back and gluteals.

Prone Back Extension

Lie face down, hands clasped behind back. Count 1: Lift upper torso until shoulders and upper chest are off Deck. Hold 3-5 seconds. Avoid hyperextension of back. Count 2: Return to start position. Variations to increase difficulty: Place hands behind back (easiest), behind head, straight over head (most difficult). Works lower back.

Rear Thigh Raises

Start on and knees and forearms. Lift left leg, keeping it bent 90o, so that left knee is no higher than hips. Keep back flat. Count 1: Lower left leg 6 inches. Count 2: Lift leg to start position. Switch legs and repeat. Works gluteals. Variation to increase difficulty: Straighten leg to be lifted.

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Hand to Knee Squat

Place feet shoulder-width apart, arms at sides. Count 1: Bend at hip and knees, keep back straight and feet flat, until your fingertips pass knees. Knees should not go beyond toes. Count 2: Push through the heels to return to start position. Works quadriceps, hamstrings, and gluteals.

Burt Reynolds

Lie on left side with head supported by hand, bend right leg and place it in front of left knee. Count 1: Lift left leg approximately 8 inches off deck. Count 2: Lower left leg to 1 inch above the deck. Repeat for the right leg. Works inner thigh (hip adductors).

Leg Lifts

Lie on left side, bend both knees at a 90o angle from torso. Count 1: Lift right leg 6-8 inches, keeping knee and ankle level. Count 2: Lower right leg to 1 inch above left leg. Repeat for the left leg. Works outer thigh (hip abductors).

One-Legged Squat

Shift weight to right leg, lifting the left leg straight out in front of you. Count 1: Bend right knee until it is over your toes. Count 2: Push up through right heel to return to start position. Repeat using other leg. Works quadriceps, hamstring, and gluteal muscles.

Calf Raises

Stand on step with heels hanging off edge. Count 1: Lift heels 3 inches. Count 2: Lower heels 3 inches. Works calf muscles. Variations: Perform exercise with toes pointed inward, straight forward, and turned outward.

Abdominal Exercises

Abdominal muscles help support the lower back. Therefore, strong abdominal muscles can decrease the risk of developing lower back pain. When doing abdominal exercises on the deck, only a portion of the abdominal's range of motion is being strengthened because your lower back is flattened. However, by placing a rolled towel under your lower back you can extend the range of motion for abdominal exercises (see Figure 8-1).

Figure 8-1. Range of Motion of the Abdominals

Flexion (75-90o)

Neutral (0o)

Extension (30o)

Flexion (75-90o)

A rolled towel under the lower back increases trunk extension when performing abdominal exercises.

In this section two common abdominal exercises, the curl-up and the crunch, will be described. The curl-up, used on the PRT as a measure of muscle endurance, targets both the abdominal and hip flexor muscles. The form for the curl-up is:

  • Lie on back with knees bent, feet flat on deck, heels 10 inches from buttocks and held down by a partner. Cross arms and hands on chest or shoulders.
  • Curl torso up, touching elbows to upper thighs while hands remain on the chest or shoulders. Exhale as you lift.
  • Lie back until the lower edge of your shoulder blades touches the deck. Inhale as you lower.

The crunch is similar to the curl-up but is performed within a smaller range of motion. The torso is lifted by abdominal muscles during a crunch. The form for the crunch is:

  • Lie on back with knees bent 90°, feet flat on deck, shoulder width apart. Do not anchor your feet. (Anchoring your feet or placing your legs out straight on the deck will target your hip flexors, not your abdominals.)
  • Place fingertips lightly on the back of the head, elbows out to sides and in line with ears. (Variations to this include arms at sides, arms across chest, and arms above head.)
  • Lift torso until the shoulder blades come off the deck by moving rib cage toward hips. Exhale as you lift. Look up at the ceiling to prevent neck strain.
  • Return to the starting position. Inhale as you lower.

Some people may develop lower back pain if they perform curl-ups routinely. For them, the crunch is recommended as an alternate exercise. Regardless of which exercise you choose when training, focus on the quality, not the quantity, of repetitions. If you perform either exercise rapidly, you are using momentum and not building abdominal strength!

From OPNAVIST 6110.1E

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