Muscular Fitness

ASSESSING MUSCULAR FITNESS

OUTLINE

  • Basics and Terminology

  • Assessing muscle strength

  • Assessing muscle endurance

  • Assessing muscle power

BASICS AND TERMINOLOGY

  • Muscular Fitness: Refers to the ability of muscles to perform work, encompassing strength, endurance, and power.

    • Muscular strength: Maximum force that can be generated by a muscle or muscle group.

    • Muscular endurance: The ability to maintain a force output over a given period of time.

    • Muscular power: The muscle’s ability to exert force per unit of time.

    • Flexibility: The ability to move a joint through its full range of motion (ROM).

MUSCLE FIBER CHARACTERISTICS

  • Slow Twitch (ST) Fiber:

    • Appearance: Dark-red color.

    • Diameter: Small diameter.

    • Capillary Density: High capillary density.

    • Functional Characteristics:

    • Slow velocity of shortening.

    • Low force production.

    • Fatigue resistant.

    • Metabolic Classification: Oxidative.

  • Fast Twitch (FTB) Fiber:

    • Appearance: White color.

    • Diameter: Large diameter.

    • Capillary Density: Low capillary density.

    • Functional Characteristics:

    • Fast velocity of shortening.

    • High force production.

    • Fatigue rapidly.

    • Metabolic Classification: Glycolytic.

  • Fast Twitch (FTA) Fiber:

    • Appearance: White color.

    • Diameter: Large diameter.

    • Capillary Density: Medium capillary density.

    • Functional Characteristics:

    • Fast velocity of shortening.

    • High force production.

    • Fatigue rapidly.

    • Metabolic Classification: Oxidative/Glycolytic.

TERMINOLOGY CONTINUED

  • Static:

    • Isometric: Tension increases without a change in muscle length.

  • Dynamic:

    • Concentric: Tension increases as the muscle shortens.

    • Eccentric: Tension maintained while the muscle lengthens.

    • Isokinetic: Maximal tension is applied through a full range of motion at a constant velocity; muscle shortens (e.g., arm stroke during swimming).

STANDARDIZATION OF TESTING

  • Important factors in muscular fitness testing:

    • Conduct an aerobic warm-up.

    • Ensure equipment familiarization.

    • Maintain strict posture during testing.

    • Ensure consistent repetition duration (movement speed).

    • Ensure full range of motion is utilized.

    • Use spotters when necessary for safety.

    • Maintain consistent order of events in testing.

  • Accurate Testing: Retesting and individual comparisons must be reliable and standardized.

  • Flexibility Testing: Should always be the last part of the muscular fitness assessment.

REPORTING RESULTS

  • Change in muscular fitness over time should be reported as absolute values (e.g., in newtons, kilograms [kg], or pounds [lb]).

  • Comparative Analysis: When making comparisons between individuals, report relative values (e.g., per kilogram of body weight [kg ∙ kg⁻¹]).

  • Issues in Reporting:

    • Ensure the sample utilized for comparison is representative.

    • Standardized protocols may be lacking, especially regarding the exact test (e.g., free weights vs. machine weights).

    • Biomechanics may vary significantly between equipment from different manufacturers.

MUSCULAR STRENGTH

ISOMETRIC MEASUREMENT OF STRENGTH

  • Utilizes cable tensiometers and dynamometers to measure isometric muscle strength at various joint angles.

  • Advantages:

    • Lightweight and portable; suitable for field testing.

    • Generally allows for 2-3 trials at each joint angle (best score recorded).

    • Simple and safe to administer; identifies maximum voluntary contraction (MVC).

  • Disadvantages:

    • Some apparatus can be expensive.

    • Measures static strength specific to the tested muscle group and joint angle, limiting overall strength assessment.

Hand Dynamometers

  • Measures grip strength, useful for predicting functionality and mortality in the elderly.

  • Procedure:

    • Adjust the grip size for comfort.

    • Maintain an erect standing position with shoulder adducted, elbow flexed at 90 degrees, forearm neutral, wrist slightly extended (0-30º).

    • Perform the squeeze without extraneous body movement, recording the best of three trials.

Back & Leg Dynamometers

  • Measures strength of back and legs.

  • Procedures for Leg Testing:

    • Trunk erect, knees flexed at 130-140º.

    • Maintain a pronated grip across thighs, exert maximum force extending the knees while keeping back still.

    • Record the best of three attempts with 1-minute rest intervals.

  • Procedures for Back Testing:

    • Ensure the knees are fully extended and the trunk erect.

    • Alternate grip (pronated for right hand and supinated for left hand), with the bar on the thighs.

    • Pull the handbar straight using back muscles without leaning back.

    • Record the best of three trials.

ISOMETRIC MEASUREMENT OF STRENGTH - Static Strength Norms

  • Classification for Strength Measurements (kg):

    Classification

    Left Grip (kg)

    Right Grip (kg)

    Back Strength (kg)

    Leg Strength (kg)

    Total Strength (kg)

    Relative Strength*

    Men

    Excellent

    >68

    >70

    >209

    >241

    >587

    >7.50

    Good

    56-67

    62-69

    177-208

    214-240

    508-586

    7.10-7.49

    Average

    43-55

    48-61

    126-176

    160-213

    375-507

    5.21-7.09

    Below Average

    39-42

    41-47

    91-125

    137-159

    307-374

    4.81-5.20

    Poor

    <39

    <41

    <91

    <137

    <307

    <4.81

    | Women | | | | | | |
    | Excellent | >37 | >41 | >111 | >136 | >324 | >5.50 |
    | Good | 34-36 | 38-40 | 98-110 | 114-135 | 282-323 | 4.80-5.49 |
    | Average | 22-33 | 25-37 | 52-97 | 66-113 | 164-281 | 2.90-4.79 |
    | Below Average | 18-21 | 22-24 | 39-51 | 49-65 | 117-163 | 2.10-2.89 |
    | Poor | <18 | <22 | <39 | <49 | <117 | <2.10 |

    • *Relative strength is calculated by dividing total strength by body mass (kg).

    • For individuals over age 50, scores should be reduced by 10% to account for muscle mass loss due to aging.

    • Source: Corbin et al., 1978.

DYNAMIC MEASUREMENT OF STRENGTH

  • One Repetition Maximum (1-RM):

    • Most common measurement of muscular strength.

    • Represents the maximum weight that can be lifted for one complete repetition, determined through trial and error.

  • Advantages:

    • Applicable to specific muscle groups based on needs; inexpensive.

    • Forces applied dynamically.

  • Disadvantages:

    • May cause muscle damage (soreness) in many individuals.

    • Does not measure maximum force at all joint angles.

    • The number of lifts at a percentage of 1-RM can vary significantly between muscle groups.

Procedures for 1-RM Testing

  • Testing should occur post-familiarization/practice sessions.

  • Warm up with several submaximal repetitions of the exercise used for 1-RM determination.

  • Determine 1-RM within four trials with 3-5 min rest between trials.

  • Select an initial weight close to perceived capacity (50%-70% of capacity).

  • Progressively increase weight by 5-10% for upper body and 10-20% for lower body until the individual cannot complete the selected repetition(s).

  • Record the final successfully lifted weight as absolute 1-RM or relative 1-RM.

BENCH PRESS CLASSIFICATIONS

  • Fitness Categories for Upper Body Strength for Men and Women by Age:

    • Bench Press Weight Ratio = weight pushed in lb + body weight in lb.

    • Men's Bench Press Categories:

      Age Group

      <20

      20-29

      30-39

      40-49

      50-59

      60+

      Superior

      >1.76

      >1.63

      >1.35

      >1.20

      >1.05

      >0.94

      Excellent

      1.76

      1.63

      1.35

      1.20

      1.05

      0.94

      Good

      1.46

      1.48

      1.24

      1.10

      0.97

      0.89

      Average

      1.38

      1.37

      1.17

      1.04

      0.93

      0.84

      Below Average

      1.34

      1.32

      1.12

      1.00

      0.90

      0.82

      Poor

      1.29

      1.26

      1.08

      0.96

      0.87

      0.79

    • Women's Bench Press Categories:
      | Age Group | <20 | 20-29 | 30-39 | 40-49 | 50-59 | 60+ | |-----------------|-----|--------|--------|--------|--------|-------| | Superior | >0.88| >1.01 | >0.82 | >0.77 | >0.68 | >0.72 |
      | Excellent | 0.88 | 1.01 | 0.82 | 0.77 | 0.68 | 0.72 |
      | Good | 0.83 | 0.90 | 0.76 | 0.71 | 0.61 | 0.64 |
      | Average | 0.81 | 0.80 | 0.70 | 0.62 | 0.55 | 0.54 |
      | Below Average | 0.76 | 0.77 | 0.65 | 0.60 | 0.53 | 0.53 |
      | Poor | 0.71 | 0.69 | 0.61 | 0.56 | 0.51 | 0.50 |

LEG PRESS CLASSIFICATIONS


  • Fitness Categories for Leg Strength by Age and Sex:

    • Leg Press Weight Ratio = weight pushed in lb + body weight in lb.


    • Men's Leg Press Categories:

      Age Group

      20-29

      30-39

      40-49

      50-59

      60+

      Well Above Average

      2.27

      2.07

      1.92

      1.80

      1.73

      Above Average

      2.13

      1.93

      1.82

      1.71

      1.62

      Average

      1.91

      1.71

      1.62

      1.52

      1.43

      Below Average

      1.83

      1.65

      1.57

      1.46

      1.38

      Well BelowAverage

      1.51

      1.43

      1.35

      1.22

      1.16


    • Women's Leg Press Categories:

      Age Group

      20-29

      30-39

      40-49

      50-59

      60+


      Well Above Average

      1.82

      1.61

      1.48

      1.37

      1.32


      Above Average

      1.68

      1.47

      1.37

      1.25

      1.18


      Average

      1.44

      1.27

      1.18

      1.05

      0.99


      Below Average

      1.37

      1.21

      1.13

      0.99

      0.93


      Well Below Average

      1.27

      1.15

      1.08

      0.95

      0.88

      DYNAMIC MEASUREMENT OF STRENGTH

      1-RM Strength to Body Mass Ratios

      • Dynamic strength measurements include:

        • Bench press, arm curl, lat pull-down, leg press, leg extension, leg curl.

      • Scores classification based on total points:

        Total Points

        Category

        48-60

        Excellent

        37-47

        Good

        25-36

        Average

        13-24

        Fair

        0-12

        Poor

        • Additional information can be derived from the NSCA strength training protocols and guidelines.

      MUSCULAR ENDURANCE

      • Muscular Endurance:

        • Defined as “the ability of a muscle group to execute repeated muscle actions over a period of time sufficient to cause muscular fatigue.”

        • Absolute Muscular Endurance: Measured directly.

        • Relative Muscular Endurance: Relative to the 1-RM.

      YMCA Test Procedure

      • Perform as many repetitions as possible at specified cadence:

        • Male participants use an 80 lb (36.4 kg) barbell.

        • Female participants use a 35 lb (15.9 kg) barbell.

        • Termination Criteria: Test concludes when the participant can no longer maintain the cadence (30 repetitions/min or 60 bpm).

      YMCA Norms for Bench Press Test

      % Rank

      Men (Ages)

      18-25

      26-35

      36-45

      46-55

      56-65

      >65

      Excellent

      64

      61

      55

      47

      41

      36

      Good

      41

      37

      32

      25

      21

      16

      Above Average

      33

      29

      25

      20

      14

      10

      Average

      28

      24

      21

      14

      11

      8

      Below Average

      22

      20

      17

      11

      8

      6

      Poor

      17

      16

      12

      8

      4

      3

      Very Poor

      <10

      <9

      <6

      <2

      <1

      <1

      ACSM Push-up Test Procedures for Assessing Endurance

      • Push-up Protocol:

        1. Males start in the standard down position with hands pointing forward under the shoulder, back straight, using toes as the pivotal point.

        2. Females start in the modified knee push-up position with legs together and back straight, utilizing knees as the pivotal point.

        3. Test subject must raise the body by straightening the elbows and return to the down position, chin touches the mat, stomach off the mat.

        4. Maximal push-ups performed consecutively without rest are counted as the score.

        5. The test stops if the subject strains forcibly or cannot maintain proper technique.

      ACSM Push-up Test Fitness Categories

      Category

      Men (Ages)

      20-29

      30-39

      40-49

      50-59

      60-69

      Excellent

      M

      ≥36

      ≥30

      ≥27

      ≥25

      ≥24

      Very Good

      29-35

      21-29

      22-29

      20-26

      17-24

      Good

      22-28

      15-20

      17-21

      13-19

      13-16

      Fair

      ≤9

      ≤11

      ≤9

      ≤9

      ≤4

      Poor

      10-14

      8-12

      5-10

      Very Poor

      6-9

      2-4

      ≤1

      MUSCULAR POWER

      • Muscular Power: Defined as the muscle’s ability to exert force per unit of time; includes measurements of speed and mean power.

        • Mean Power: Average power developed over a period.

        • Peak Power: Highest power developed during maximum effort.

      Assessing Muscular Power
      Wingate Cycle Test

      • Warm-up:

        • 2-minute warm-up at 1-1.5kp, 50 rpm.

        • 2-3 practice sprints lasting 5-10 seconds at ± 120 rpm.

      • Test Phase:

        • Subject pedals as fast as possible continuously for 30 seconds against resistance of 0.075 x kg body weight.

      • Cool Down:

        • Continue to pedal at a lower resistance to recover from the sprint.

      Percentile Norms for Average and Peak Power

      % Rank

      Average Power (Male)

      Average Power (Female)

      Peak Power (Male)

      Peak Power (Female)

      90

      662 W

      470 W

      822 W

      560 W

      80

      618 W

      419 W

      777 W

      527 W

      70

      600 W

      410 W

      757 W

      505 W

      60

      577 W

      391 W

      721 W

      480 W

      50

      565 W

      381 W

      689 W

      449 W

      Margaria-Kalamen Stair Test

      • Protocol:

        • Measure weight in kg.

        • Conduct 3 trials.

      • Calculation of Power:

        • Power [(Body weight x 9.807) x Height] / Time.

        • Example: If John weighs 180 lb (81.8 kg) and takes 0.8 seconds to climb six steps with a combined height of 49.5 inches (1.26 m), calculated power would be 1,262 watts.

      Margaria Classification Chart (for Men's Power)

      Age

      Excellent

      Good

      Average

      Fair

      Poor

      15-20

      >2,197 watts

      1,844-2,197 watts

      1,471-1,824 watts

      1,108-1,461 watts

      <1,108 watts

      20-30

      >2,059 watts

      1,726-2,059 watts

      1,373-1,716 watts

      1,040-1,226 watts

      <1,040 watts

      30-40

      >1,648 watts

      1,383-1,648 watts

      1,098-1,373 watts

      834-1,088 watts

      <834 watts

      40-50

      >1,226 watts

      1,040-1,226 watts

      834-1,030 watts

      637-824 watts

      <637 watts

      50+

      >961 watts

      814-961 watts

      647-804 watts

      490-637 watts

      <490 watts

      1RM for Assessing Power Exercises

      • 1 Repetition Maximum (1-RM) is typically used for strength exercises, but power-oriented exercises such as the power clean, hang clean, clean and jerk, snatch, vertical jump, standing long jump, and push press assess different aspects of muscular power rather than strict strength.

      Assessing Vertical Jump

      • Assessment method to determine how high an individual can jump, with various protocols and measuring devices available (e.g., Vertec).

      • Comparison charts available based on sports and athlete categories.

      Vertical Jump Scores Example by Sport/Position

      • NCAA Div I College Football:

        • Split ends, strong safetys, and defensive backs: 31.5 in (80 cm).

        • Wide receivers and linebackers: 29-31 in (74-79 cm).

        • Quarterbacks: 28.5 in (72 cm).

      • High School Football Players:

        • Backs and receivers: 24 in (61 cm).

        • Linemen: 22 in (56 cm).

      • NCAA Div I College Basketball Players:

        • Male Players: 21 in (53 cm), Female Players: 15 in (38 cm).

        • Recreational College Athletes: Men: 24 in (61 cm), Women: 15 in (38 cm).

        • Sedentary College Students: Men: 16-20.5 in (41-52 cm), Women: 8-14 in (20-36 cm).