Physical Fitness

Physical Fitness: The ability to carry out daily tasks without undue fatigue, enjoy leisure life, and meet emergency demands.
It consists of attributes that are either health- or skill-related, measured with specific tests.

2 Components of Physical Fitness

Definition: The ability to exercise continuously for extended periods without tiring; the efficiency of your heart and lungs in delivering oxygen to working muscles during sustained physical activity.
Key Metric: Measured by VO2 max(maximum amount of oxygen your body can use during exercise).
Variables:
- Intensity: How hard or vigorously an individual works during exercise.
- Duration: How long the exercise will be performed.
- Frequency: Number of times an individual exercises each week.
- Mode: The kind of activity selected (e.g., brisk walking, jogging).

Muscles consist of bundles of fibers containing smaller strands called myofibrils.
Hypertrophy: Growth of muscle fibers/myofibrils from strength training.
Atrophy: Shrinking of muscle fibers from lack of activity.

Slow-Twitch Fibers: Fatigue resistant, contract less rapidly/forcefully, rely primarily on oxidative energy system.
Fast-Twitch Fibers: Contract rapidly and forcefully, fatigue quickly, rely more on non-oxidative energy system.
Motor Units: Nerves connected to muscle fibers recruited to exert force.

Muscular Strength: The maximal amount of force a muscle/muscle group can exert in a single effort (1 repetition maximum).

Training Target: High weight, low reps (4–8 reps, 80%+ of 1RM), 2–5 minute rest intervals.

Isotonic Contraction: Muscle tension remains unchanged while muscle length changes.

Concentric: Muscle shortens as force overcomes resistance.
Eccentric: Muscle lengthens as force is insufficient to overcome resistance.

Isometric Contraction: Muscle length and joint position remain unchanged despite increasing tension.
Isokinetic Contraction: Muscle contracts/shortens at a constant speed against variable resistance (often using specialized machines).
Physiological Benefits of Strength Training:

Definition: The ability of muscles to work repeatedly over an extended period without undue fatigue.
Training Target: Low weight, high reps (12–20+ reps, 30–50% of 1RM), 30–90 second rest intervals.
How Hypertrophy/Building Occurs: Resistance training causes protein degradation (breakdown of muscle tissue), followed by repair with high repetition sets and moderate rest.
Types of Dynamic Exercise:

Variable Resistance Training: Changing weight keeps muscle working at max capacity across full range of motion.
Eccentric Loading: Placing weight on a muscle as it extends.
Plyometrics: Quick stretch/load followed immediately by a powerful contraction.
Speed Loading: Moving/lifting weight as fast as possible.
Isokinetic Exercise: Pushing against force moving at a constant speed.

Feature	Muscular Strength	Muscular Endurance
Definition	Max force in a single effort	Repeat contractions without tiring
Weight	Heavy weight (80%+ 1RM)	Moderate/low weight (30–50% 1RM)
Reps	1–8 reps	12–20+ reps
Example	1-Rep Max Squat	50 Consecutive Push-ups

Definition: The ability to move different body joints through their complete range of motion.
3 Factors Influencing Flexibility:

Definition: The proportion of fat-free mass (muscles, bones, organs, water) relative to fat mass in the human body.
Body Types (Somatotypes):

Endomorph: Higher body fat relative to muscle, wider frame, larger waist/abdomen, rounded features; easier weight gain and higher obesity risk.
Mesomorph: Medium athletic build, higher muscle mass relative to fat, square/rectangular frame, broad chest/shoulders, narrow waist.
Ectomorph: Linear, lean, tall build with long limbs, narrow shoulders/waist, low body fat, lower muscle mass; harder to gain muscle/fat.

Body Mass Index (BMI): A screening tool using weight relative to height squared.
BMI=height2(m2)weight (kg)

Agility: Ability to change and control body direction/position rapidly while maintaining motion.
Balance: Ability to control or stabilize the body when stationary or moving.
Coordination: Ability to use senses together with body parts during physical movement.
Speed: Ability to move the body or body parts swiftly.
Power: Ability to move body parts swiftly while exerting maximum muscular force.
Reaction Time: Ability to reach or respond quickly to visual, auditory, or tactile stimuli.