What is physical fitness?
Physical fitness is being able to do daily tasks, play and sport without getting tired too quickly, with energy left for emergencies.
Five health-related components
- Cardio-respiratory endurance (stamina): heart and lungs supply oxygen for a long time. Test: 12-minute run or beep test.
- Muscular strength: the most force a muscle can make once. Test: hand-grip.
- Muscular endurance: using a muscle again and again without tiring. Test: push-ups or sit-ups in 1 minute.
- Flexibility: how far joints can move. Test: sit-and-reach.
- Body composition: the share of fat compared with muscle, bone and water.
Skill-related fitness
- Speed: moving fast from one place to another (30 m sprint).
- Agility: changing direction quickly with control (shuttle run).
- Power: strength used quickly (standing long jump).
- Balance: staying steady, still or moving (stork stand).
- Coordination: body parts working together smoothly (catching a ball).
- Reaction time: how quickly you respond to a signal (ruler drop).
Different sports need different mixes: a sprinter needs speed and power; a badminton player needs agility and reaction time; a gymnast needs balance and flexibility.
Planning training: FITT, warm-up and cool-down
FITT
- Frequency: how often, such as 3–5 days a week.
- Intensity: how hard. For stamina, work at 60–85% of maximum heart rate. Maximum heart rate ≈ 220 − age.
- Time: how long, such as 30–60 minutes.
- Type: which activity: running, cycling, swimming (aerobic); weights, push-ups (strength); stretching, yoga (flexibility).
A session
- Warm-up (5–10 min): light jogging and moving stretches. Raises heart rate and muscle temperature, lowers injury risk.
- Main workout.
- Cool-down (5–10 min): slow walking and static stretches. Heart rate returns gently to normal.
Training principles and effects of exercise
Principles
- Overload: make the body work harder than usual.
- Progression: increase the load slowly (about 10% a week).
- Specificity: train the component your sport needs.
- Rest and recovery: muscles rebuild between sessions; sleep matters.
- Reversibility: stop training and fitness fades.
- Individual differences: plans suit each person's age, health and goals.
Short-term effects
Faster heart rate and breathing, sweating, warm red skin, tired muscles.
Long-term effects
A bigger, stronger heart pumps more blood each beat, so the resting heart rate falls; stronger muscles and bones; better lung use; healthier body weight; better mood and sleep; lower risk of diabetes and heart disease. Sticking with it (perseverance) is what makes the changes last.
Key formulas and definitions
- Maximum heart rate ≈ 220 − age (beats per minute)
- Target zone = 60% to 85% of maximum heart rate
- Heart rate = beats in 15 s × 4
- FITT: Frequency, Intensity, Time, Type
- Health components: cardio-respiratory endurance, strength, muscular endurance, flexibility, body composition
- Skill components: speed, agility, power, balance, coordination, reaction time
Worked examples
1. Find the maximum heart rate and target zone of a 15-year-old.
Max = 220 − 15 = 205 bpm. 60% of 205 = 123; 85% of 205 ≈ 174. Target zone ≈ 123–174 bpm.
2. You count 22 pulse beats in 15 seconds. What is your heart rate?
22 × 4 = 88 beats per minute.
3. Write a FITT plan to improve stamina for a Class 8 student.
Frequency: 4 days a week. Intensity: jog at about 70% of max heart rate. Time: 30 minutes. Type: jogging or cycling. Add 2–3 minutes each week (progression).
4. Which component does each test measure: sit-and-reach, shuttle run, 1-minute push-ups?
Sit-and-reach: flexibility. Shuttle run: agility. 1-minute push-ups: muscular endurance.
Common mistakes
- Mixing up strength and endurance. Strength is one big effort; endurance is many repeats.
- Skipping the warm-up to save time. Cold muscles tear more easily.
- Adding too much too fast. Progression should be slow, or you get injured.
- Thinking a thin person is always fit. Body composition is only one of five health components.