Physical activity is defined as any bodily movement produced by skeletal muscles that results in energy expenditure. The energy expenditure can be measured in kilocalories. Physical activity in daily life can be categorized into occupational, sports, conditioning, household, or other activities.
Exercise is a subset of physical activity that is planned, structured, and repetitive and has as a final or an intermediate objective the improvement or maintenance of physical fitness.
Example of Exercise:
A boy performing Illinois agility testing
Physical fitness is a set of attributes that are either health- or skill-related. Being physically fit has been defined as “the ability to carry out daily tasks with vigor and alertness, without undue fatigue and with ample energy to enjoy leisure-time pursuits and to meet unforeseen emergencies.” The degree to which people have these attributes can be measured with specific tests.
Physical fitness measures are closely allied with disease prevention and health promotion, thus it is common and appropriate to measure components of physical fitness before preventive and rehabilitative programs. Physical fitness can be modified through regular physical activity and exercise. Physical fitness components have been shown to have a significant positive relationship with enhanced outcomes in physical activity, including sports participation.
Components of Physical Fitness:
Physical fitness can be broadly divided into Metabolic fitness, Health- related and Skill-related.
Metabolic Fitness:
It depicts the physiological systems’ state of health when they are at rest.
Blood pressure- It involves indirect measuring the effectiveness of the heartbeat, adequacy of blood volume and presence of any obstruction to vascular flow through the use of sphygmomanometer and a stethoscope. Normal BP is 120/80
Pulse rate- It is the number of throbbing sensations felt over a peripheral artery when the heart beats. Normal ranges from 60 to 100 pulses per min.
Blood insulin- Insulin test measures blood samples for the amount circulating insulin, responsible for blood glucose usage by surrounding tissue. Normal values are 5 to 20µm/mL while fasting. Lower than normal suggest Type 1 diabetes and above normal level suggests Type 2 diabetes.
Health-Related Fitness:
Good health have a strong relationship with health-related components of physical fitness because it determines the ability of an individual to perform daily activities with vigor and demonstrate the capacities associated with low risk of premature development of the hypokinetic diseases. It is also known as physiological fitness.
The main aims of health-related fitness testing are:
- Educating clients about their present health-related fitness status in relationship to standard age and sex- matched normative values
- Providing data that are helpful for making clinical decision while prescribing exercises to address all fitness components
- Collecting baseline and follow up data that allow evaluation of progress by exercise program participants
- Motivating participants by establishing SMART goals
- Stratifying cardiovascular risk
The components of health-related fitness includes: body composition, muscular endurance, muscular strength, cardiovascular endurance and flexibility.
Body Composition:
Body composition can be expressed as the relative percentage of body mass that is fat and fat-free tissue using a two-compartment model. It can be measured with both laboratory and field techniques that vary in terms of complexity, cost, and accuracy. Anthropometric methods are: Body mass index, Circumferences and Skinfold measurements. Hydrodensitometry weighing, plethysmography are some methods used in lab.
-Skin fold thickness– measurements involve measuring skin and subcutaneous adipose tissues at several different standard anatomical sites around the body and converting these measurements to percentage body fat.
% body fat = (fat weight/total body weight) * 100
-BMI- Key index for relating a person’s body weight to height.
BMI= M/(H*H), where M= body mass in kilograms and H= height in meters
(A higher BMI score usually indicates higher levels of body fat)
-Waist to hip ratio- Measured using a tape measure around the waist and the largest hip circumference. The ratio is a simple calculation of the waist girth divided by the hip girth.
Muscular Fitness:
It includes muscular endurance and strength. They determine bone mass, glucose tolerance, musculo-tendinous integrity, and ability to carry out ADLs. Muscle function tests are very specific to the muscle group tested, the type of contraction, the velocity of muscle movement, the type of equipment, and the joint range of motion.
Muscular Strength:
It is the muscle’s ability to exert force at high intensities over short periods of time. Static or isometric strength can be assessed by using various devices such as dynamometer and tensiometers. 1 repetition maximum (1- RM), the greatest resistance that can be moved through the full range of motion in a controlled manner with good posture, is the standard for dynamic strength assessment.
Muscular Endurance:
It is the ability of muscle group to execute repeated contractions over a period of time sufficient to cause muscle fatigue, or to maintain a specific percentage of the maximal voluntary contraction for a prolonged period of time. Absolute muscular endurance is the total number of repetitions at a given amount of resistance is measured. Relative muscular endurance is the number of repetitions performed at a percentage of the 1 -RM (e.g: 75%) which is in both pre- and post-testing.
Cardiorespiratory Endurance:
Cardiorespiratory fitness is related to the ability to perform large muscle, dynamic, moderate to high intensity exercise for prolonged periods. The performance depends upon the functional state of the respiratory, cardiovascular, and skeletal muscle systems. The criterion measure of cardiorespiratory fitness is determined by maximal oxygen uptake (VO2max). The best measure of cardio-respiratory fitness is VO2 max, volume (V) of oxygen used when a person reaches his or her maximum (max) ability to supply oxygen (O2) to muscle tissue during exercise.
Flexibility:
Flexibility is the ability to move a joint through its complete range of motion. It is important in the ability to carry out ADLs and in athletic performance. It depends on a number of specific variables including distensibility of the joint capsule, adequate warm-up, and muscle viscosity. Flexibility is joint specific, thus, no single flexibility test can be used to evaluate total body flexibility. Goniometers, inclinometers, electrogoniometers, the Leighton flexometer and tape measures are some common devices to measure flexibility in degrees. Sit and reach test is one of the flexibility tests.
Skill-Related Fitness:
It is also known as performance-related fitness components. It is associated with athletic competition but should be considered in the overall fitness of all individuals. These components are pertaining with the athletic ability of an individual. There are 6 components of physical fitness: balance, co-ordination, agility, speed, power, and reaction time.
Balance:
Balance is the ability of an individual to maintain their line of gravity within their base of support. It can be classified into static and dynamic. Balance is control by three different system: somatosensory, visual and vestibular system. It can be assessed by various outcome tools such as berg balance scale, BESTest, etc.
One leg stance test- Individual is asked to stand on 1 leg for 10s with eyes open or closed
Sharpened Romberg’s test- Individual stands with both feet in tandem (feet touching heel to toe) with eyes closed to mask the problem with balance.
Time up and Go test- This balance test measures the time needed to rise to standing from a chair, walk 3m, turn, walk back to chair and sit down.
Coordination:
It is the ability to use the senses, such as sight and hearing, together with body parts in performing motor tasks smoothly and accurately. Alternate hand wall toss test is one the test via which co-ordination can be assessed.
Finger to Nose test– This test is designed to observe the smoothness and timing of arm movement. The individual is asked to repetitively touch the nose using the index finger and then to touch the clinician’s outstretched finger.
Power:
It is the rate at which one is able to exert maximal force. Vertical jump test and hop test are some examples of power testing for lower extremity. Medicine ball throw test can be used to assess upper extremity power.
Agility:
Agility is defined as “a rapid whole-body movement with change of velocity or direction in response to a stimulus”. It performs a series of explosive power movements in a rapid succession in opposing directions.
Reaction Time:
Reaction time is related to the time elapsed between stimulation and the beginning of the reaction to it. Reaction time is affected by several variables including attentive, cognitive and motor functions. Three basic reaction time paradigms have been described:
simple reaction time has a single stimulus and a single predefined response,
recognition reaction time has several false stimuli mixed with one correct stimulus prompting the response, and
choice reaction time involves multiple stimuli and differing responses for each stimulus. It can be assessed via Drop-Ruler test. Please watch the video below to understand this test.
Speed:
It relates to the ability to perform a movement within a short period of time. Speed combined with strength will provide power and force. Sprint test is one of the example of the test that can be used to examine person’s speed.
