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Chapter 12: Physical Activity & Fitness
Lesson 1 — Benefits of Physical Activity
Physical activity is any body movement that uses muscles and burns energy. Regular activity strengthens the heart, builds strong bones, improves mental health, and reduces chronic disease risk.
CDC Recommendation
Teens should get at least 60 minutes of moderate-to-vigorous physical activity every day, including aerobic, muscle-strengthening, and bone-strengthening activities.
Teens should get at least 60 minutes of moderate-to-vigorous physical activity every day, including aerobic, muscle-strengthening, and bone-strengthening activities.
Physical BenefitsStronger heart, lungs, muscles, bones; healthy weight; better sleep
Mental BenefitsReduced anxiety/depression; better focus; improved self-esteem
Social BenefitsTeamwork, cooperation, friendship, belonging
Academic BenefitsBetter concentration, memory, and classroom performance
Quick Check: Name one physical and one mental benefit of regular physical activity.
Lesson 2 — Types of Fitness
Physical fitness has five health-related components and six skill-related components. Building all areas creates well-rounded fitness.
- Cardiorespiratory endurance — heart/lung efficiency during sustained activity
- Muscular strength — maximum force a muscle can exert
- Muscular endurance — ability to repeat muscle contractions over time
- Flexibility — range of motion at joints
- Body composition — ratio of fat to lean tissue
Skill-Related Fitness
Agility, balance, coordination, power, reaction time, and speed are skill-related components important for sports and daily movement.
Agility, balance, coordination, power, reaction time, and speed are skill-related components important for sports and daily movement.
Quick Check: What is the difference between muscular strength and muscular endurance?
Lesson 3 — The FITT Principle
The FITT principle guides how to design an effective fitness program. Each letter stands for a key variable:
F — FrequencyHow often you exercise (e.g., 5 days/week)
I — IntensityHow hard you work (moderate vs. vigorous)
T — TimeHow long each session lasts (e.g., 30–60 min)
T — TypeWhat kind of activity (running, swimming, lifting)
Applying FITT helps you progressively overload muscles — gradually increasing challenge so the body adapts and improves without injury.
Quick Check: How would you use the FITT principle to improve cardiorespiratory endurance?
Lesson 4 — Preventing Injuries & Staying Safe
Exercise-related injuries are common but largely preventable. Smart training habits protect your body for lifelong activity.
- Always warm up (5–10 min light movement) and cool down (stretching)
- Use proper form and technique — most injuries come from poor mechanics
- Wear appropriate gear and footwear
- Stay hydrated — drink water before, during, and after activity
- Rest and recover — overtraining leads to fatigue and injury
- Listen to your body — pain is a signal, not a badge of honor
RICE for Minor Injuries
Rest · Ice · Compression · Elevation — the first steps for sprains, strains, and minor injuries before seeking medical care.
Rest · Ice · Compression · Elevation — the first steps for sprains, strains, and minor injuries before seeking medical care.
Quick Check: What does RICE stand for and when would you use it?
Chapter Vocabulary
Physical activityAny movement produced by skeletal muscles that requires energy expenditure.
Physical fitnessThe ability to carry out daily tasks with vigor and without undue fatigue.
Cardiorespiratory enduranceThe ability of the heart and lungs to supply oxygen to working muscles during sustained activity.
Muscular strengthThe maximum force a muscle or muscle group can exert in a single effort.
Muscular enduranceThe ability of a muscle to perform repeated contractions over time.
FlexibilityThe ability of joints to move through their full range of motion.
FITT principleA framework for fitness programming: Frequency, Intensity, Time, and Type.
Progressive overloadGradually increasing the stress placed on the body during exercise to continue improving.
Warm-upLight activity before exercise that prepares the body and reduces injury risk.
Cool-downGradual reduction in activity intensity after exercise to safely lower heart rate and stretch muscles.