Physical Fitness: Definition of Terms

Physical Fitness:

Physical Activity: any movement carried out by the skeletal muscles requiring energy.

Exercise:

COMPONENTS OF PHYSICAL FITNESS

I.  Muscular Strength

II.  Muscular Endurance

III.  Cardiorespiratory Endurance

IV.  Flexibility

V.  Psychomotor Ability

VI.  Body Composition

Muscular Strength

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·  can be defined as the ability of a muscle or muscle group to exert force against resistance. (Strength = Force)

·  Force generated by a muscular contraction may be applied against an object, as in tackling in football, or against a fixed object, such as the platform in diving

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Power

·  Force that can be produced at high speeds to overcome gravity, and consequently accelerate the body or an object.

·  Ability to exert force is dependant on muscular strength and is a decisive factor in performance of most sports.

Muscular Endurance

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·  Static exercises involve sustained contractions which can compromise blood flow

·  As a result the oxygen available is rapidly used up and lactic acid accumulates causing fatigue.

·  Example: Flexed arm hang. Your heart and lungs are not taxed, but your arm muscles feel a strong burning sensation and fatigue rapidly.

·  Conversely, dynamic exercises involve continuous rhythmical contractions and relaxations that allow for oxygen to be continually delivered to the muscle and lactic acid to be removed.

·  Thus, other physiological systems play a significant role in muscular endurance such as the cardio-respiratory system. Exercises such as running, swimming, or biking involve large muscle groups as well as Cardio-respiratory endurance.

Cardio-respiratory Endurance

·  Involves both the heart (cardio) and the lungs (respiratory).

·  Main function is to provide oxygen to the tissues.

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·  Max VO2 (MVO2) is also the maximal rate of aerobic metabolism and is the single most important criterion of physical fitness.

·  Cardio-respiratory fitness is the ability to produce energy through an improved delivery of oxygen to the working muscles.

·  Needed for exertions over relatively longer periods of time regardless of the activity.

·  Closely related to muscular endurance as the working muscles rely on oxygen supply sent by the heart delivered via the blood, and “used” by the muscles.

Max VO2

·  Can be measured, estimated, or predicted in many ways.

·  Measuring the MVO2 of a person running on a treadmill involves having a person run at a given speed or workload for a few minutes (2-3) at each workload. The workload is gradually increased by increasing the speed or the treadmill slope. At each new workload, the person’s demand of oxygen increases, i.e. as the workload is increased more oxygen is taken up by the lungs, delivered by the heart, and utilized by the muscles. However, eventually a point will be reached where the increased workload cannot be supported by an increase in oxygen uptake. Oxygen consumption is said to have reached a plateau or reached maximal value. This plateau is known as one’s max VO2.

Prediction of MVO2

·  Based on linear correlation of an increased heart rate with an increased workload.

·  At each new workload, as more oxygen is required, the heart will pump more blood, delivering more oxygen to the exercising muscles. Thus, at each new workload heart rate will also increase and eventually reach a maximal value.

Absolute MVO2

·  Expressed in L/min

·  Increased mass of person generally equals increased MVO2

Relative MVO2

·  To account for mass differences, MVO2 is expressed in a relative manner,

·  Usually in ml/kg/min.

·  Used to compare two athletes playing different sports or of different sizes

·  Tells us consumed volume of oxygen in millilitres per kilogram of body weight/min.

Flexibility

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·  Determined primarily by joint structure and to a lesser extent by muscle elasticity and length.

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·  Collagen: main structural protein in connective tissues.

o  Provide structure/support to tissues, ligaments, tendons, and joints.

o  Can withstand very high tensile forces.

o  Another protein, elastin, provides athlete with stretching ability.

·  Factors that influence flexibility:

o 

·  Flexibility promotes good joint health, slows joint deterioration and generally improves quality of life for most individuals.

·  May also prevent lower back pain and injuries as well as reduce the frequency and severity of injuries.

Active Flexibility

Passive Flexibility

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·  Passive flexibility exercises help achieve a wider ROM than do active flexibility.

Stretching Methods

Static Stretching refers to holding a fully stretched position, such as the splits. The athlete slowly relaxes the muscles to be stretched and holds herself/himself in a stretched position over 10-30 seconds.

Dynamic Stretching or Ballistic Stretching refers to rapidly moving a joint through its full range of motion, such as the arm of a baseball pitcher. The method involves stretching with repetitive bouncing movements using small intervals, rather than just one pull. An athlete begins the first repetition over a relatively small ROM, gradually increasing the amplitude range, reaching after 10-20 movements, the maximal range.

Pre-stretching or the proprioceptive neuromuscular facilitation (PNF) method exploits the natural protective reflex of the muscle and its tendon sensors – the muscle spindles and golgi tendon organs. Most efficient stretching method.

The PNF method is done with a partner in 3 stages:

i.  active stretching phase: muscles are actively pulled to the very limit of the movement range, slowly and continuously – prevents muscle spindles from releasing the stretching reflex and thus contracting the muscles.

ii.  pre-tension phase: the trainee exerts a full static resistance ( a strong isometric contraction) against a partner for approximately seven seconds. This causes the tendon spindles to release inhibitory impulses which in turn cause an involuntary relaxation of the muscles to be stretched.

iii.  passive stretching phase: the partner pushes the body further into stretching position almost to the point of pain. This final position is then held, with all muscles relaxed, for approximately six seconds. Partner’s pressure must be applied slowly and constantly in order to prevent muscle spindles from initiating a reflex contraction, which may cause injury.

Body Composition

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·  Important date: percentages of lean body mass and fat body mass.

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·  Large number of young people in our society who are considered obese. Any fitness program, strength or cardio-vascular should be designed with an aim to help reduce body fat.

Psychomotor Ability

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·  Allows for quickness and accuracy and ease of movement

·  Integrate central nervous system with the more physical components of fitness.

The psychomotor abilities include:

  • reaction time and anticipation
  • visual skills
  • hand-eye coordination
  • perception
  • attention and concentration
  • balance
  • proprioception or muscle feeling
  • memory processes and recall
  • decision making