Cardiorespiratory Endurance

Cardiorespiratory Endurance

Cardiorespiratory endurance is measured and predicted by determining one’s VO2max. It is the ability to maintain a sufficient source of fuel, to the circulatory and respiratory systems, over an extended duration of time.

Muscular Endurance

Muscular endurance is a measurement of the ability of a muscle to contract repeatedly over a period of time.

Muscular Strength

Muscular strength is the maximal force the body can exert by contracting a muscle or muscle group at a specific contractile velocity, or simply the ability to produce muscular force.

Body Composition

Body composition is the standard scientific method of finding the absolute and relative percentages by weight and mass muscle, fat, bone, and other vital parts of the body. Previously, assessment of body composition was limited to two systems: Two-Component System and the Multiple (more than two) Component System. Current research has lead to the development of more sophisticated techniques. Many newer methods are not always implemented because cost, availability and complexity are limiting factors.

The Two Component System is based on the assumptions that; 1.) The density of fat is 0.900 g/ml at 37° C. 2.) the density of lean body mass is 1.100 g/ml 37° C.  3.) all individuals have the previously stated densities for fat and lean mass.  The assumptions did not take into consideration the variability of lean body mass as it relates to bone density, race, age, and total body water. The Multiple-Component System divides body composition into several categories: water, lipid, protein, and minerals. 

Densitometry is measuring body density in mass.  Body density (density of the body when submerged in water) is typically measured via hydro-densitometry method, or hydrostatic weighing.  It is based on the principle that when an object is submerged in water, it displaces an amount of water that is equal to a counter force that is buoyed up. Body density is determined by; 1.) measuring the volume of water displaced, and 2.) measuring the change in body weight underwater. This model has become the standard method of calculating body composition in combination with a two-component model.  Disadvantages of the method are cost and time, and some subjects have a low tolerance to submersion.  The mathematical equation does not take into account the variables in population groups when converting body density to percentage of body fat.

Skin-fold calipers are used to measure the subcutaneous fat in specific, common areas on subjects. These measurements are used to predict the percentage of body fat by plugging the measurements into various regression equations.  This is the most common and cost effective technique used today. 

Bioelectrical impedance (BIA – is the method of measuring body fat, fat-free body mass, and total body water by measuring the resistance to current passed through the body.) measures body composition by comparing a relationship between whole body electrical impedance and total body water (TBW).  BIA is based on electrical conductance and on the fact that fat-free mass has a much greater conductivity than does fat.  The BIA model is limited by changes in electrolytes in the body.

Body Mass Index (BMI) is the ratio of weight to height squared.  BMI is calculated by dividing body weight in kilometers by height in meters squared (kg/m2).  The optimal rating for BMI is between 20 to 24.9.  A BMI score less than 20 is considered underweight.  A BMI score above 25 is considered overweight.  A BMI score greater than 30 is considered obese.  High BMI scores can indicate a susceptibility to heart disease, cancer, and diabetes. 


Flexibility is defined as the range of movement (ROM) in a joint or series of joints.  Three forms of flexibility are: static, ballistic, and proprioceptive neuromuscular facilitation (PNF). Flexibility training is an important component of a balanced fitness program.  In addition, flexibility helps to improve performance, increases joint stability, increases range of motion, helps prevent injuries, decreases recovery time, and improves “warm-up” techniques.

Static stretching assumes and maintains an extended position in a slow and concise manner of a muscle or muscle group and held for 8 – 12 seconds.  During the stretch, the muscle spindle is at rest and the stretch reflex is gradually diminished.  The position should always be held just below the threshold for pain.  This is the safest and most effective type of stretch.

Ballistic stretching (kinetic flexibility) is dynamic in movements that are bouncy and quick.  It is the least effective and most dangerous type of stretch.  

Proprioceptive neuromuscular facilitation (PNF) is the type of stretching where the muscle is stretched for a period of 4 – 6 seconds and immediately followed by a static stretch for 8 – 12 seconds.  This is a contact type of stretch that requires a partner.  PNF steps involved are; 1.) the muscle group is in an elongated position, 2.) muscle is isometrically contracted and held for 6 – 10 seconds, and 3.) the muscle is then relaxed to be immediately followed by a concentric contraction of the opposing muscle group. 


A calorie is a measure of heat.  It is the amount of heat required to raise the temperature of 1 gram of water 1° C.  In fitness, a calorie is measured by energy value of food.  When choosing a dietary plan for weight loss, it is important to consider, and take into account, that 3,500 kilocalories of food energy = 1 pound of body weight.


A set of attributes or state of well being that provides optimal performance, thus enabling a person to perform a physical activity.


Exercise is defined by the components of physical activity to achieve or maintain physical fitness.  The components of physical fitness are; cardiorespiratory endurance (aerobic fitness), body composition, muscular endurance, flexibility, and muscular strength.

Household Physical Activity

Household physical activities are everyday functional chores that are performed around the home. They may include (but are not limited to) activities such as sweeping floors, scrubbing, washing windows, washing the car, and raking or mowing the lawn.


Inactivity is the act of not being active. Inactive individuals tend to be sedentary in nature and are not involved in a regular exercise program.


The amount of heat required to raise the temperature of 1 kg of water 1° C.

Light-Intensity Activities

Light (low) intensity activities are movements that will slightly raise the heart rate above normal. These activities may produce a light sweat and a slight strain in the muscle(s). These activities may include (but are not limited to) walking slowly, golf (powered cart), swimming, slow treading, gardening, bicycling in a light effort, dusting or vacuuming.


1 MET  (metabolic equivalents) = the energy (oxygen) used by the body during rest. The MET rating will increase as the intensity of the activity increases, thus the more elevated your heart rate becomes, the more oxygen your body requires to sustain itself and the higher your MET will be.

3 to 6 METs burned is considered moderate-intensity physical activity.

Greater than 6 METs burned is considered vigorous-intensity physical activity.

Moderate-Intensity Physical Activity

Moderate-intensity physical activity ranges from 40-60% of the maximal heart rate.   Moderate-intensity activity leads to slightly increased rate of breathing and slightly increased heart rate, but you should still be able to hold a conversation without difficulty.  The activity should fall within the range of 3 to 6 metabolic equivalents (METs) burned. It can also be measured by calories burned. Moderate-intensity activities burn 3.5 to 7 calories per minute (kcal/min).

Moderate-intensity activities include but are not limited to brisk walking, golf (pulling or carrying clubs), mowing lawn (power motor), tennis (doubles), bicycling 5 to 9 mph on flat terrain or with minimal hills, scrubbing floors, washing windows, and light weight lifting (Nautilus machines or free weights).

Physical Activity

Physical activity is defined by the physical exertion of the body that creates a net loss of energy.

Physical Fitness

A set of attributes or state of well being that provides optimal performance, thus enabling people to perform a physical activity that requires one or more components of fitness, cardiovascular endurance, cardiovascular strength, muscular strength and flexibility.

Regular Physical Activity

Regular physical activity is a fitness program that occurs on a consistent basis and maintained over a period of time. The program must involve either moderate exercises performed 5 or more days a week or vigorous-intensity activities or exercises performed at least 3 days a week for 20-60 minutes each session. * For a higher level of fitness, increase intensity, frequency or duration.

Vigorous-Intensity Activities

Vigorous-intensity activities involve elevating the heart rate to 60% of the max heart rate.  These activities result in increased heart rate, increased breathing and sweating. Activities include (but are not limited to) speed walking (walking a mile in less than 14 minutes) running, jogging, cycling, swimming laps, and playing endurance sports.

Weight-Bearing Physical Activity

Weight-bearing activities are physical activities that involve a load or impact, such as jumping or skipping.

    December ’09

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