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11-12th Class

Human Physiology and Biomechanics in easy notes

Afifa Asad 0

PART 1: HUMAN PHYSIOLOGY

1. Introduction to Human Physiology

Human physiology is the branch of science that studies how the human body functions. It explains how cells, tissues, organs, and systems work together to maintain homeostasis (internal balance).

In sports and physical education, physiology helps us understand:

  • How muscles produce movement
  • How the heart and lungs respond to exercise
  • How energy is produced during physical activity
  • How training improves performance

2. Cell Structure and Function

The cell is the structural and functional unit of life.

Main Parts of a Cell:

  • Cell membrane – Controls entry and exit of substances
  • Cytoplasm – Jelly-like substance where reactions occur
  • Nucleus – Control center containing DNA
  • Mitochondria – “Powerhouse” of the cell (ATP production)
  • Ribosomes – Protein synthesis

In athletes, mitochondria increase with endurance training, improving stamina.

3. Tissue System

There are four types of tissues:

  1. Epithelial Tissue – Covers body surfaces
  2. Connective Tissue – Supports organs (bone, cartilage, blood)
  3. Muscle Tissue – Produces movement
  4. Nervous Tissue – Conducts impulses

4. Skeletal System

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Functions:

  • Support
  • Protection
  • Movement
  • Blood cell formation
  • Mineral storage

Types of Bones:

  • Long bones (Femur)
  • Short bones (Carpals)
  • Flat bones (Skull)
  • Irregular bones (Vertebrae)

Types of Joints:

  • Hinge (Elbow)
  • Ball and Socket (Shoulder)
  • Pivot (Neck)
  • Gliding (Wrist)

In sports, joint mobility determines flexibility and performance.

5. Muscular System

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Types of Muscles:

  1. Skeletal (Voluntary)
  2. Smooth (Involuntary)
  3. Cardiac

Structure of Skeletal Muscle:

  • Muscle → Fascicle → Fiber → Myofibril → Sarcomere

Sliding Filament Theory:

  • Actin and myosin filaments slide
  • ATP provides energy
  • Results in contraction

Types of Contraction:

  • Isometric
  • Isotonic
    • Concentric
    • Eccentric

Training increases muscle fiber size (hypertrophy).

6. Cardiovascular System

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Structure:

  • 4 chambers (2 atria, 2 ventricles)

Blood Circulation:

  • Pulmonary circulation
  • Systemic circulation

Important Terms:

  • Heart Rate (HR)
  • Stroke Volume (SV)
  • Cardiac Output (CO = HR × SV)

Exercise increases cardiac output and strengthens the heart.

7. Respiratory System

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Organs:

  • Nose
  • Trachea
  • Lungs
  • Alveoli

Breathing Mechanism:

  • Inhalation – diaphragm contracts
  • Exhalation – diaphragm relaxes

VO₂ max is the maximum oxygen consumption capacity.

8. Nervous System

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Divisions:

  • Central Nervous System (CNS)
  • Peripheral Nervous System (PNS)

Motor Unit:

One motor neuron + muscle fibers it controls

Better coordination improves sports performance.

9. Energy Systems

1. ATP-PC System

  • Immediate energy
  • 0–10 seconds
  • Used in sprinting

2. Anaerobic Glycolysis

  • No oxygen
  • Produces lactic acid
  • 10 sec – 2 min

3. Aerobic System

  • Uses oxygen
  • Long-duration activities

10. Endocrine System

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Major Glands:

  • Pituitary
  • Thyroid
  • Adrenal
  • Pancreas

Hormones regulate growth, metabolism, and stress response.

PART 2: BIOMECHANICS

11. Introduction to Biomechanics

Biomechanics is the study of mechanical laws applied to human movement.

It helps in:

  • Improving technique
  • Preventing injuries
  • Enhancing performance

12. Types of Motion

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  1. Linear Motion
  2. Angular Motion
  3. General Motion

13. Newton’s Laws of Motion

1st Law – Law of Inertia

Body remains at rest or motion unless acted upon by force

2nd Law – Force = Mass × Acceleration

F = ma

3rd Law – Action = Reaction

Used in jumping, sprinting, throwing.

14. Levers in Human Body

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Types:

  1. First Class (Neck)
  2. Second Class (Ankle)
  3. Third Class (Biceps curl)

Most body levers are third class.

15. Centre of Gravity & Stability

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Factors Affecting Stability:

  • Base of support
  • Height of COG
  • Mass
  • Friction

Lower COG = more stability.

16. Friction

  • Static friction
  • Dynamic friction

Essential in sprint start and grip sports.

17. Projectile Motion

Used in:

  • Basketball shots
  • Javelin throw
  • Shot put

Key factors:

  • Angle of release
  • Velocity
  • Height

18. Angular Motion

  • Torque
  • Angular velocity
  • Moment of inertia

Used in gymnastics and diving.

19. Planes and Axes

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Planes:

  • Sagittal
  • Frontal
  • Transverse

Axes:

  • Longitudinal
  • Transverse
  • Sagittal

20. Mechanical Principles in Sports

  • Force summation
  • Momentum
  • Impulse
  • Balance

Used in throwing and striking games.

PART 3: APPLICATION IN SPORTS TRAINING

Physiological Adaptations to Training

Cardiovascular:

  • Lower resting HR
  • Increased stroke volume

Muscular:

  • Hypertrophy
  • Increased strength

Respiratory:

  • Increased lung capacity

Injury Prevention

  • Proper biomechanics
  • Warm-up
  • Flexibility
  • Correct posture

Quick Revision Points

✔ Physiology studies body function
✔ Biomechanics studies movement mechanics
✔ Energy systems provide ATP
✔ Newton’s laws apply to sports
✔ Most body levers are third class
✔ Stability depends on COG

🧾 CONCLUSION

Human Physiology and Biomechanics

Human physiology and biomechanics together form the scientific backbone of physical education, sports science, and movement studies. While physiology explains how the body functions, biomechanics explains how the body moves according to mechanical laws. When studied together, these two disciplines provide a complete understanding of human performance — from cellular energy production to complex athletic movements like sprinting, jumping, throwing, and balancing.

Human physiology teaches us that the human body is an extraordinarily well-coordinated system made up of billions of cells organized into tissues, organs, and organ systems. Each system has a specific role, yet they function interdependently to maintain homeostasis — the internal balance required for survival. The skeletal system provides structure and protection, the muscular system produces movement, the cardiovascular system transports oxygen and nutrients, the respiratory system ensures gas exchange, the nervous system controls coordination, and the endocrine system regulates hormones that influence growth, metabolism, and stress responses. During exercise, all these systems interact efficiently to meet increased physical demands.

One of the most important contributions of physiology to sports science is the understanding of energy systems. Every movement in the human body requires ATP (adenosine triphosphate), the energy currency of the cell. Depending on the duration and intensity of activity, the body uses different energy pathways: the ATP-PC system for short explosive efforts, anaerobic glycolysis for moderate high-intensity activities, and the aerobic system for long-duration endurance performance. This knowledge helps coaches design training programs according to the specific demands of a sport. For example, a 100-meter sprinter relies heavily on the ATP-PC system, whereas a marathon runner depends primarily on aerobic metabolism.

Another major aspect of physiology is adaptation to training. The human body has the remarkable ability to adapt when exposed to consistent physical stress. Regular endurance training increases stroke volume, lowers resting heart rate, and enhances oxygen-carrying capacity. Strength training results in muscular hypertrophy and improved neuromuscular coordination. Respiratory efficiency improves with systematic aerobic exercise. These adaptations highlight the principle of progressive overload — the idea that the body improves when challenged beyond its usual limits. Without understanding physiological responses, effective training planning would not be possible.

Biomechanics, on the other hand, applies the laws of physics to human movement. It explains why certain techniques are more effective and efficient than others. By applying Newton’s laws of motion, we understand how force, mass, and acceleration influence movement. For example, in sprinting, greater ground reaction force produces greater acceleration. In jumping, the action-reaction principle explains how pushing downward against the ground propels the body upward. In throwing sports, the sequential summation of forces from large body segments to smaller ones increases velocity and power.

The study of levers in the human body is another critical biomechanical concept. Most joints function as third-class levers, allowing speed and range of motion at the expense of mechanical advantage. Understanding lever systems helps athletes optimize technique and helps physiotherapists analyze movement patterns. Similarly, the concept of center of gravity and base of support explains balance and stability. Athletes lower their center of gravity to increase stability in sports like wrestling and football, while gymnasts manipulate body alignment to maintain equilibrium.

Projectile motion is another area where biomechanics is applied extensively. In sports like basketball, javelin throw, and shot put, the angle of release, velocity, and height of projection determine performance outcomes. By analyzing these variables, athletes can improve accuracy and distance. Angular motion concepts such as torque, angular velocity, and moment of inertia are particularly relevant in gymnastics, diving, and figure skating, where body rotation is central to performance.

The integration of physiology and biomechanics is especially important in injury prevention and rehabilitation. Improper technique can place excessive stress on joints and muscles, leading to overuse injuries. Biomechanical analysis helps identify faulty movement patterns, while physiological knowledge aids in designing recovery programs that promote tissue repair and restore function. For example, understanding muscle contraction types (concentric, eccentric, isometric) helps trainers create safe strengthening protocols during rehabilitation.

Another critical area where physiology and biomechanics intersect is motor learning and neuromuscular coordination. The nervous system plays a vital role in controlling voluntary movements. Efficient coordination depends on motor unit recruitment, reaction time, and proprioception. Biomechanics provides insights into movement mechanics, while physiology explains neural control mechanisms. Together, they enhance skill acquisition and performance refinement.

In modern sports science, technology has strengthened the application of both fields. Tools such as motion analysis systems, force plates, electromyography (EMG), and VO₂ max testing allow detailed study of movement and physiological response. These advancements have made training more scientific, precise, and individualized. Athletes can now optimize technique, monitor workload, and prevent overtraining with evidence-based methods.

Beyond sports, human physiology and biomechanics have importance in daily life. Proper posture, ergonomic workplace design, lifting techniques, and physical fitness all depend on these principles. Understanding how the body functions and moves reduces the risk of lifestyle-related disorders such as obesity, cardiovascular disease, and musculoskeletal problems. Knowledge of physiology encourages healthy habits, while biomechanics promotes safe movement patterns.

In the educational context, these subjects build analytical thinking and scientific understanding among students. They connect theoretical science concepts with practical real-world applications. Students studying physical education gain deeper insights into why warm-ups are essential, why stretching improves flexibility, why rest is necessary for recovery, and why technique determines performance efficiency.

Ultimately, human physiology explains the internal processes that generate energy and sustain life, while biomechanics explains the external expression of those processes in movement. One focuses on biological mechanisms; the other focuses on mechanical laws. Together, they provide a holistic understanding of human performance.

As sports continue to evolve and competition becomes more intense, the importance of scientific training based on physiology and biomechanics will only increase. Athletes who understand these principles gain a competitive advantage. Coaches who apply them design better programs. Medical professionals who integrate them improve recovery outcomes. Researchers who study them continue to push the boundaries of human performance.

In conclusion, human physiology and biomechanics are not isolated subjects but complementary sciences that collectively explain how the human body functions, adapts, and performs. They form the foundation of sports science, physical education, rehabilitation, and fitness training. Mastery of these concepts empowers individuals to train intelligently, move efficiently, prevent injuries, and achieve optimal performance. Their relevance extends from elite athletics to everyday health, making them essential fields of study in modern education and sports development.

✅ HUMAN PHYSIOLOGY AND BIOMECHANICS

100 Multiple Choice Questions (MCQs) with Answers

🔬 PART A: HUMAN PHYSIOLOGY (1–50)

1. The functional unit of the human body is:

A) Tissue
B) Organ
C) Cell
D) System
Answer: C

2. The powerhouse of the cell is:

A) Nucleus
B) Ribosome
C) Mitochondria
D) Lysosome
Answer: C

3. The largest bone in the human body is:

A) Tibia
B) Femur
C) Humerus
D) Radius
Answer: B

4. The number of bones in an adult human body is:

A) 200
B) 206
C) 210
D) 198
Answer: B

5. The hinge joint is found in the:

A) Shoulder
B) Hip
C) Elbow
D) Neck
Answer: C

6. Cardiac muscle is found in the:

A) Brain
B) Stomach
C) Heart
D) Lungs
Answer: C

7. The basic contractile unit of muscle is:

A) Myofibril
B) Sarcomere
C) Actin
D) Myosin
Answer: B

8. Oxygen is transported in blood by:

A) Plasma
B) Platelets
C) Hemoglobin
D) WBC
Answer: C

9. Normal resting heart rate of adults is approximately:

A) 40–50 bpm
B) 60–100 bpm
C) 110–130 bpm
D) 120–140 bpm
Answer: B

10. The chamber of heart that pumps blood to the body is:

A) Right atrium
B) Left atrium
C) Right ventricle
D) Left ventricle
Answer: D

11. Gas exchange occurs in:

A) Bronchi
B) Trachea
C) Alveoli
D) Larynx
Answer: C

12. The diaphragm helps in:

A) Digestion
B) Breathing
C) Circulation
D) Excretion
Answer: B

13. The nervous system is divided into:

A) CNS and PNS
B) Blood and lymph
C) Bones and muscles
D) Arteries and veins
Answer: A

14. A motor unit consists of:

A) Muscle only
B) Neuron only
C) Motor neuron and muscle fibers
D) Bone and muscle
Answer: C

15. ATP is stored in:

A) Liver
B) Blood
C) Muscles
D) Kidneys
Answer: C

16. The ATP-PC system provides energy for:

A) Marathon
B) 100m sprint
C) 5 km run
D) Cycling (long distance)
Answer: B

17. Anaerobic glycolysis produces:

A) Oxygen
B) Carbon dioxide
C) Lactic acid
D) Water
Answer: C

18. Aerobic system requires:

A) Nitrogen
B) Oxygen
C) Carbon monoxide
D) Hydrogen
Answer: B

19. The endocrine gland known as master gland is:

A) Thyroid
B) Adrenal
C) Pituitary
D) Pancreas
Answer: C

20. Insulin is secreted by:

A) Thyroid
B) Pancreas
C) Liver
D) Adrenal
Answer: B

21. Blood pressure is measured in:

A) kg
B) mmHg
C) m/s
D) Joules
Answer: B

22. Stroke volume is:

A) Heart beats per minute
B) Blood pumped per beat
C) Oxygen intake
D) Blood pressure
Answer: B

23. Cardiac output equals:

A) HR + SV
B) HR × SV
C) HR – SV
D) SV ÷ HR
Answer: B

24. White blood cells help in:

A) Oxygen transport
B) Immunity
C) Clotting
D) Digestion
Answer: B

25. Hemoglobin contains:

A) Calcium
B) Iron
C) Sodium
D) Potassium
Answer: B

26. The longest muscle in the body is:

A) Biceps
B) Triceps
C) Sartorius
D) Deltoid
Answer: C

27. Flexion decreases the:

A) Angle of joint
B) Strength
C) Mass
D) Bone length
Answer: A

28. Hypertrophy means:

A) Decrease in muscle size
B) Increase in muscle size
C) Fat loss
D) Bone growth
Answer: B

29. VO₂ max indicates:

A) Strength
B) Speed
C) Endurance capacity
D) Flexibility
Answer: C

30. The axial skeleton includes:

A) Arms
B) Legs
C) Skull and vertebral column
D) Pelvis
Answer: C

31–50 (Short Format)

  1. Plasma is the liquid part of blood – A
  2. Tendons connect muscle to bone – B
  3. Ligaments connect bone to bone – C
  4. The smallest bone is stapes – A
  5. Smooth muscle is involuntary – D
  6. RBC lifespan is about 120 days – B
  7. Normal body temperature is 37°C – C
  8. Adrenal gland secretes adrenaline – A
  9. Neuron carries impulses – B
  10. Reflex action is automatic – D
  11. Cartilage reduces friction – A
  12. Platelets help clotting – C
  13. Tibia is in leg – B
  14. Radius is in forearm – D
  15. Heart has four chambers – A
  16. Lungs are spongy organs – C
  17. Myosin is thick filament – B
  18. Actin is thin filament – D
  19. Growth hormone is secreted by pituitary – A
  20. Homeostasis means internal balance – C

⚙️ PART B: BIOMECHANICS (51–100)

51. Biomechanics studies:

A) Cells
B) Chemicals
C) Movement mechanics
D) Nutrition
Answer: C

52. First law of motion is:

A) Acceleration
B) Inertia
C) Reaction
D) Gravity
Answer: B

53. F = ma is:

A) First law
B) Second law
C) Third law
D) Law of gravity
Answer: B

54. Action-reaction principle is:

A) 1st law
B) 2nd law
C) 3rd law
D) Friction law
Answer: C

55. A third-class lever example is:

A) Neck
B) Foot
C) Biceps curl
D) Seesaw
Answer: C

56. Center of gravity is the point where:

A) Force acts
B) Weight acts
C) Friction acts
D) Speed acts
Answer: B

57. Stability increases when:

A) COG is high
B) Base is narrow
C) Base is wide
D) Mass decreases
Answer: C

58. Projectile motion depends on:

A) Angle
B) Velocity
C) Height
D) All
Answer: D

59. Friction helps in:

A) Slipping
B) Sprint start
C) Falling
D) Jumping less
Answer: B

60. Angular motion occurs around:

A) Axis
B) Line
C) Surface
D) Plane
Answer: A

61–100 (Short Format)

  1. Linear motion is straight line – A
  2. Torque causes rotation – B
  3. Momentum = mass × velocity – C
  4. Impulse = force × time – D
  5. Sagittal plane divides left/right – A
  6. Frontal plane divides front/back – B
  7. Transverse plane divides top/bottom – C
  8. Fulcrum is pivot point – D
  9. Second class lever example is ankle – A
  10. Gymnast lowers COG for balance – B
  11. Speed equals distance/time – C
  12. Acceleration is change in velocity – D
  13. Gravity pulls downward – A
  14. Force summation increases power – B
  15. Balance depends on COG – C
  16. Mass is measured in kg – D
  17. Work = force × distance – A
  18. Power = work/time – B
  19. Elasticity stores energy – C
  20. Reaction time affects performance – D
  21. Base of support improves stability – A
  22. Moment of inertia affects rotation – B
  23. Resistance training increases torque – C
  24. Longer lever increases speed – D
  25. Foot acts as second-class lever – A
  26. Neck acts as first-class lever – B
  27. Third-class lever favors speed – C
  28. Friction resists motion – D
  29. Kinematics studies motion – A
  30. Kinetics studies forces – B
  31. Jumping uses action-reaction – C
  32. Throwing uses force summation – D
  33. Stability decreases with high COG – A
  34. Wider stance improves balance – B
  35. Aerodynamics affects projectile – C
  36. Force plate measures ground force – D
  37. Angular velocity is rotational speed – A
  38. Flexion occurs in sagittal plane – B
  39. Rotation occurs in transverse plane – C
  40. Biomechanics improves technique – D

✅ HUMAN PHYSIOLOGY AND BIOMECHANICS

100 Very Short Type Questions with Answers

(One-line / 1–2 sentence answers – Exam Ready)

🔬 PART A: HUMAN PHYSIOLOGY (1–50)

1. What is physiology?

Physiology is the study of functions of the human body.

2. What is the structural unit of the body?

Cell.

3. What is homeostasis?

Maintenance of internal body balance.

4. How many bones are in an adult human body?

206 bones.

5. Which bone is the longest?

Femur.

6. What connects muscle to bone?

Tendon.

7. What connects bone to bone?

Ligament.

8. What is the contractile unit of muscle?

Sarcomere.

9. Name the three types of muscles.

Skeletal, smooth, cardiac.

10. Which muscle is voluntary?

Skeletal muscle.

11. What is hypertrophy?

Increase in muscle size.

12. What is atrophy?

Decrease in muscle size.

13. What is normal body temperature?

37°C (98.6°F).

14. What is normal resting heart rate?

60–100 beats per minute.

15. What is stroke volume?

Amount of blood pumped per heartbeat.

16. Define cardiac output.

Heart rate × stroke volume.

17. What carries oxygen in blood?

Hemoglobin.

18. What is the lifespan of RBC?

About 120 days.

19. Where does gas exchange occur?

Alveoli.

20. Which muscle helps in breathing?

Diaphragm.

21. What is VO₂ max?

Maximum oxygen consumption capacity.

22. Name the master gland.

Pituitary gland.

23. Which gland secretes insulin?

Pancreas.

24. What is ATP?

Energy currency of the cell.

25. Which system controls coordination?

Nervous system.

26. What is a motor unit?

One motor neuron and the muscle fibers it controls.

27. What is plasma?

Liquid part of blood.

28. What is systole?

Contraction phase of heart.

29. What is diastole?

Relaxation phase of heart.

30. What is anaerobic respiration?

Energy production without oxygen.

31. Name the three energy systems.

ATP-PC, anaerobic glycolysis, aerobic.

32. Which energy system is used in 100m sprint?

ATP-PC system.

33. Which energy system is dominant in marathon?

Aerobic system.

34. What is lactic acid?

By-product of anaerobic glycolysis.

35. What are white blood cells?

Cells that fight infection.

36. What is blood pressure?

Force of blood against artery walls.

37. What is hemoglobin made of?

Iron-containing protein.

38. What is reflex action?

Automatic response to stimulus.

39. What is cartilage?

Flexible connective tissue in joints.

40. What is flexibility?

Range of motion at a joint.

41. What is endurance?

Ability to sustain activity for long time.

42. What is strength?

Ability to exert force.

43. What is speed?

Distance covered per unit time.

44. What is coordination?

Ability to use body parts smoothly.

45. What is metabolism?

Chemical reactions in the body.

46. What is respiration?

Process of taking oxygen and releasing carbon dioxide.

47. What is adrenaline?

Hormone released during stress.

48. What is growth hormone responsible for?

Body growth and development.

49. What is muscular contraction?

Shortening of muscle fibers.

50. What is oxygen debt?

Extra oxygen required after exercise.

⚙️ PART B: BIOMECHANICS (51–100)

51. What is biomechanics?

Study of mechanical principles of human movement.

52. What is motion?

Change in position.

53. Name three types of motion.

Linear, angular, general.

54. What is linear motion?

Movement in a straight line.

55. What is angular motion?

Movement around an axis.

56. State Newton’s First Law.

Law of inertia.

57. State Newton’s Second Law formula.

F = ma.

58. State Newton’s Third Law.

Every action has equal and opposite reaction.

59. What is force?

Push or pull.

60. What is inertia?

Resistance to change in motion.

61. What is friction?

Force that resists motion.

62. What is gravity?

Force that pulls objects toward earth.

63. What is center of gravity?

Point where body weight is concentrated.

64. What is base of support?

Area beneath body that supports it.

65. What increases stability?

Lower COG and wider base.

66. What is a lever?

Rigid bar that rotates around fulcrum.

67. Name three classes of levers.

First, second, third.

68. Which lever is most common in body?

Third-class lever.

69. What is fulcrum?

Pivot point of lever.

70. What is torque?

Rotational force.

71. What is momentum?

Mass × velocity.

72. What is impulse?

Force × time.

73. What is work?

Force × distance.

74. What is power?

Work ÷ time.

75. What is projectile motion?

Motion of object thrown in air.

76. What affects projectile distance?

Angle, velocity, height.

77. What is angular velocity?

Speed of rotation.

78. What is moment of inertia?

Resistance to rotation.

79. What is sagittal plane?

Divides body into left and right.

80. What is frontal plane?

Divides body into front and back.

81. What is transverse plane?

Divides body into upper and lower.

82. What is flexion?

Decreasing joint angle.

83. What is extension?

Increasing joint angle.

84. What is abduction?

Movement away from midline.

85. What is adduction?

Movement toward midline.

86. What is rotation?

Circular movement around axis.

87. What is balance?

Ability to maintain equilibrium.

88. What is equilibrium?

State of balanced forces.

89. What improves jumping height?

Greater force application.

90. What improves throwing distance?

Force summation.

91. What is reaction time?

Time taken to respond to stimulus.

92. What is acceleration?

Rate of change of velocity.

93. What is velocity?

Speed with direction.

94. What is mass?

Amount of matter in body.

95. What is elasticity?

Ability to return to original shape.

96. What is mechanical advantage?

Ratio of output force to input force.

97. What is kinetic energy?

Energy of motion.

98. What is potential energy?

Stored energy.

99. Why is friction important in sports?

Prevents slipping.

100. Why is biomechanics important?

It improves technique and prevents Injuries

✅ Human Physiology (1–10)

1. What is Human Physiology?

Human physiology is the branch of biology that studies how the human body functions. It explains how organs, tissues, cells, and systems such as circulatory, respiratory, and nervous systems work together to maintain life and internal balance under different conditions.

2. What is Homeostasis?

Homeostasis is the body’s ability to maintain a stable internal environment despite changes in external conditions. It regulates body temperature, blood sugar level, pH balance, and fluid levels through coordinated actions of the nervous and endocrine systems.

3. Explain Cardiac Output.

Cardiac output is the amount of blood pumped by the heart in one minute. It is calculated by multiplying stroke volume by heart rate. It increases during exercise to supply more oxygen and nutrients to working muscles.

4. What is Blood Pressure?

Blood pressure is the force exerted by circulating blood on the walls of arteries. It is measured in two values: systolic pressure (during heart contraction) and diastolic pressure (during relaxation). Normal adult blood pressure is approximately 120/80 mmHg.

5. Explain Aerobic and Anaerobic Respiration.

Aerobic respiration uses oxygen to break down glucose and produce energy (ATP), carbon dioxide, and water. Anaerobic respiration occurs without oxygen and produces less ATP along with lactic acid, commonly during high-intensity physical activity.

6. What is VO₂ Max?

VO₂ max refers to the maximum amount of oxygen a person can utilize during intense exercise. It is an important indicator of cardiovascular endurance and aerobic fitness. Higher VO₂ max values indicate better stamina and performance capacity.

7. Describe the Sliding Filament Theory.

The sliding filament theory explains muscle contraction. During contraction, actin and myosin filaments slide past each other, shortening the muscle fiber. This process requires ATP and calcium ions, enabling movement and force production.

8. What is Muscle Fatigue?

Muscle fatigue is a temporary reduction in the muscle’s ability to generate force. It occurs due to lactic acid accumulation, depletion of energy stores, or inadequate oxygen supply during prolonged or intense physical activity.

9. Explain the Role of the Nervous System.

The nervous system controls and coordinates body activities by transmitting electrical impulses through neurons. It processes sensory information, regulates voluntary and involuntary actions, and maintains communication between the brain, spinal cord, and body parts.

10. What is Thermoregulation?

Thermoregulation is the body’s process of maintaining a constant internal temperature. It involves sweating, shivering, and blood vessel dilation or constriction to balance heat production and heat loss, ensuring optimal functioning of organs.

✅ Biomechanics (11–20)

11. What is Biomechanics?

Biomechanics is the study of human movement using principles of physics and mechanics. It analyzes forces, motion, and body mechanics to improve sports performance, prevent injuries, and enhance rehabilitation practices.

12. Explain Newton’s First Law of Motion.

Newton’s First Law states that a body remains at rest or continues in uniform motion unless acted upon by an external force. This principle explains inertia, such as a football remaining stationary until kicked.

13. Explain Newton’s Second Law of Motion.

Newton’s Second Law states that force equals mass multiplied by acceleration (F = ma). It means greater force produces greater acceleration. In sports, applying more force helps athletes move faster or throw objects farther.

14. Explain Newton’s Third Law of Motion.

Newton’s Third Law states that for every action, there is an equal and opposite reaction. For example, when a runner pushes against the ground, the ground pushes back, propelling the runner forward.

15. What is Centre of Gravity?

The centre of gravity is the point where the entire body weight appears to act. A lower centre of gravity increases stability, which is important in sports like wrestling, gymnastics, and football.

16. What are the Three Classes of Levers?

Levers are rigid bars that rotate around a fulcrum. First-class levers have the fulcrum between effort and load, second-class levers have load in the middle, and third-class levers have effort in the middle. The human body mainly uses third-class levers.

17. What is Torque?

Torque is the rotational force that causes an object to turn around an axis. It depends on the amount of force applied and the distance from the pivot point. Greater torque produces more rotational movement.

18. Explain Projectile Motion.

Projectile motion occurs when an object is thrown into the air and moves under the influence of gravity. Its path is curved, and performance depends on angle, velocity, and height of release, important in sports like shot put.

19. What is Angular Momentum?

Angular momentum is the product of moment of inertia and angular velocity. It remains conserved unless acted upon by an external force. Athletes control body rotation speed by changing body position, such as tucking during a somersault.

20. Importance of Biomechanics in Sports.

Biomechanics helps improve technique, enhance performance, and reduce injury risk. By analyzing movement patterns, coaches can correct posture, optimize force application, and increase efficiency in sports skills like running, jumping, and throwing.

✅ Human Physiology – Long Answer Questions (1–15)

1. Explain the structure and functions of the human heart.

The human heart is a muscular organ located in the thoracic cavity between the lungs. It has four chambers: two atria and two ventricles. The right side receives deoxygenated blood from the body and pumps it to the lungs for oxygenation, while the left side pumps oxygenated blood to the entire body. Valves such as the tricuspid, mitral, pulmonary, and aortic valves prevent backflow of blood. The heart works through rhythmic contraction and relaxation known as the cardiac cycle. It maintains continuous blood circulation, ensuring oxygen and nutrients reach tissues while removing waste products like carbon dioxide. The heart plays a crucial role in maintaining blood pressure and supporting metabolic activities, especially during exercise when demand for oxygen increases.

2. Describe the process of respiration in humans.

Respiration is the process by which the body takes in oxygen and releases carbon dioxide. It includes two main stages: breathing and cellular respiration. Breathing involves inhalation, where oxygen-rich air enters the lungs, and exhalation, where carbon dioxide is expelled. In the lungs, oxygen diffuses into the bloodstream through alveoli. Cellular respiration occurs in the mitochondria, where oxygen helps break down glucose to produce energy in the form of ATP. Aerobic respiration requires oxygen and produces large amounts of energy, while anaerobic respiration occurs without oxygen and produces less energy along with lactic acid. Efficient respiration is essential for sustaining life and supporting physical activities.

3. Explain the sliding filament theory of muscle contraction.

The sliding filament theory explains how muscles contract to produce movement. Muscle fibers contain myofibrils made up of actin (thin filaments) and myosin (thick filaments). During contraction, myosin heads attach to actin filaments forming cross-bridges. Using energy from ATP, the myosin heads pull the actin filaments inward, shortening the sarcomere, which is the functional unit of muscle. Calcium ions released from the sarcoplasmic reticulum enable this interaction by exposing binding sites on actin. When ATP is depleted or calcium is removed, the muscle relaxes. This coordinated sliding action causes muscles to shorten and generate force, allowing body movements such as walking, running, and lifting.

4. Discuss the role of the nervous system in human movement.

The nervous system controls and coordinates all voluntary and involuntary movements. It consists of the central nervous system (brain and spinal cord) and peripheral nervous system. Sensory neurons transmit information from receptors to the brain, while motor neurons carry impulses to muscles. The brain processes information and sends signals to muscles for contraction. Reflex actions are rapid, automatic responses controlled by the spinal cord. During physical activity, the nervous system ensures coordination, balance, and precision of movements. It also regulates heart rate and breathing rate during exercise. Efficient neural control improves reaction time, agility, and athletic performance.

5. Explain cardiac output and its significance during exercise.

Cardiac output is the volume of blood pumped by the heart per minute and is calculated as stroke volume multiplied by heart rate. At rest, cardiac output is about 5 liters per minute, but it can increase significantly during exercise. During physical activity, heart rate and stroke volume rise to supply more oxygen and nutrients to working muscles. Increased cardiac output helps remove metabolic waste such as carbon dioxide and lactic acid. Athletes typically have higher stroke volumes and more efficient hearts, allowing them to maintain high performance levels. Thus, cardiac output is a key indicator of cardiovascular fitness and endurance capacity.

6. Describe the endocrine system and its importance.

The endocrine system consists of glands that secrete hormones directly into the bloodstream. Major glands include the pituitary, thyroid, adrenal, pancreas, and gonads. Hormones regulate growth, metabolism, reproduction, stress response, and fluid balance. For example, insulin controls blood glucose levels, while adrenaline prepares the body for emergency situations. The pituitary gland acts as the “master gland” by controlling other endocrine glands. Hormonal balance is essential for maintaining homeostasis. During exercise, hormones like adrenaline and cortisol help increase energy availability and improve performance. Dysfunction in the endocrine system can lead to disorders such as diabetes or thyroid imbalance.

7. Explain the concept of homeostasis and its mechanisms.

Homeostasis refers to the body’s ability to maintain a stable internal environment despite changes in external conditions. It regulates factors such as body temperature, blood pressure, glucose levels, and pH. The body uses feedback mechanisms, mainly negative feedback, to maintain balance. For example, when body temperature rises, sweating occurs to cool the body. If blood glucose increases, insulin is released to lower it. The nervous and endocrine systems work together to monitor and adjust these conditions. Homeostasis ensures optimal functioning of enzymes and cells, which is essential for survival and efficient physical performance.

8. Discuss aerobic and anaerobic energy systems.

The body produces energy through aerobic and anaerobic systems. The aerobic system uses oxygen to break down carbohydrates and fats, producing large amounts of ATP for prolonged activities like long-distance running. The anaerobic system works without oxygen and includes the ATP-PC system and lactic acid system. It provides quick energy for short, high-intensity activities such as sprinting or weightlifting. However, it produces lactic acid, which can cause muscle fatigue. Athletes train both systems depending on their sport. A balanced development of energy systems improves endurance, strength, and overall athletic performance.

9. Explain muscle fatigue and its causes.

Muscle fatigue is the decline in a muscle’s ability to generate force. It occurs due to factors such as depletion of ATP, accumulation of lactic acid, electrolyte imbalance, and insufficient oxygen supply. During prolonged exercise, energy stores like glycogen become depleted, reducing performance. Fatigue can also result from neural factors when the nervous system fails to stimulate muscles effectively. Adequate rest, hydration, nutrition, and training improve fatigue resistance. Understanding muscle fatigue helps athletes manage workload and prevent injuries.

10. Describe the process of blood circulation.

Blood circulation involves the continuous movement of blood throughout the body. It occurs in two loops: pulmonary and systemic circulation. In pulmonary circulation, deoxygenated blood travels from the heart to the lungs and returns oxygenated. In systemic circulation, oxygenated blood is pumped to body tissues. Arteries carry blood away from the heart, veins return blood, and capillaries allow exchange of gases and nutrients. Circulation maintains oxygen supply, removes waste, and regulates temperature. Efficient circulation is vital during exercise to meet increased metabolic demands.

✅ Biomechanics – Long Answer Questions (16–30)

16. Explain Newton’s Laws of Motion in sports.

Newton’s three laws of motion explain human movement in sports. The first law (law of inertia) states that an object remains at rest or in motion unless acted upon by force. The second law (F=ma) explains that acceleration depends on force and mass. The third law states that every action has an equal and opposite reaction. In running, pushing the ground backward results in forward movement. These laws help improve technique and performance.

17. Discuss the concept of centre of gravity and stability.

The centre of gravity is the point where body weight is evenly distributed. Stability depends on base of support, height of centre of gravity, and body mass. A lower centre of gravity and wider base increase stability. Athletes in wrestling or gymnastics adjust body position to maintain balance. Understanding this concept prevents falls and improves performance.

18. Explain the types of levers in the human body.

The human body uses three types of levers. In first-class levers, the fulcrum lies between effort and load (neck movement). In second-class levers, the load lies between fulcrum and effort (standing on toes). In third-class levers, effort lies between fulcrum and load (biceps curl). Most body movements involve third-class levers for speed and range of motion.

19. Describe projectile motion in sports.

Projectile motion occurs when an object is launched into the air and influenced by gravity. Its path depends on angle of release, velocity, and height. In shot put or javelin throw, a 45-degree angle often gives maximum range. Proper technique improves performance.

20. Explain angular motion and its importance.

Angular motion occurs when a body rotates around an axis. It is seen in gymnastics, diving, and throwing events. Control of angular velocity improves technique and performance. Conservation of angular momentum allows athletes to spin faster by tucking their body.

21. Discuss torque and rotational movement.

Torque is the turning effect of force applied at a distance from the axis. Greater force or longer lever arm increases torque. It is important in throwing, kicking, and weightlifting movements.

22. Explain friction and its role in sports.

Friction is the force opposing motion between two surfaces. It provides grip in running shoes but may reduce speed in swimming. Managing friction improves efficiency.

23. Describe balance and equilibrium.

Balance is the ability to maintain body position. Static equilibrium occurs at rest, while dynamic equilibrium occurs during movement. Athletes develop balance to prevent falls and improve skill execution.

24. Explain planes and axes of movement.

Movements occur in sagittal, frontal, and transverse planes. Each plane has a corresponding axis. Understanding planes helps analyze sports skills effectively.

25. Discuss work, power, and energy in sports.

Work is force applied over distance. Power is work done per unit time. Energy can be kinetic or potential. Athletes require high power output for explosive movements.

26. Explain reaction time and coordination.

Reaction time is the interval between stimulus and response. Coordination is smooth integration of movements. Both are essential for performance in fast-paced sports.

27. Describe gait and posture.

Gait is the pattern of walking or running. Proper posture ensures efficient movement and reduces injury risk.

28. Explain mechanical advantage.

Mechanical advantage is the ratio of load to effort. It helps determine efficiency of lever systems in the body.

29. Discuss centripetal and centrifugal forces.

Centripetal force pulls objects toward the center of rotation, while centrifugal force appears outward. These forces act during circular movements like hammer throw.

30. Explain the importance of biomechanics in injury prevention.

Biomechanics analyzes movement patterns to reduce stress on joints and muscles. Correct technique prevents injuries and enhances performance.

✅ Case-Based Questions (Human Physiology & Biomechanics)

Case 1: Marathon Runner and Fatigue

Riya is participating in a marathon. After running 25 km, she feels muscle fatigue, heavy breathing, and leg cramps. Her heart rate is significantly elevated.

Questions:

  1. Why has her heart rate increased?
  2. What type of respiration is mainly occurring?
  3. What causes muscle fatigue in this case?

Answer:
Her heart rate increases to pump more oxygenated blood to working muscles. Aerobic respiration is mainly occurring, but as intensity rises, anaerobic respiration may also contribute. Muscle fatigue is caused by glycogen depletion, lactic acid accumulation, electrolyte imbalance, and dehydration. Oxygen debt may also develop.

Case 2: Sprinter at the Starting Block

A 100-meter sprinter reacts instantly to the gunshot and accelerates quickly.

Questions:

  1. Which energy system is primarily used?
  2. Which Newton’s law applies during push-off?
  3. Why is reaction time important?

Answer:
The ATP-PC (anaerobic alactic) energy system is primarily used for short bursts. Newton’s Third Law applies, as pushing against the ground generates forward movement. Reaction time is crucial because faster response to the stimulus gives a competitive advantage.

Case 3: Weightlifter Performing a Deadlift

A weightlifter lifts a heavy barbell from the ground using proper posture.

Questions:

  1. What type of lever is mainly involved?
  2. Define torque in this context.
  3. Why is posture important?

Answer:
The movement primarily involves a third-class lever. Torque is the rotational force produced around joints during lifting. Proper posture prevents excessive stress on the spine and reduces risk of injury by distributing force efficiently.

Case 4: Football Player Dehydration

During a hot match, a football player feels dizziness and muscle cramps.

Questions:

  1. What physiological condition is occurring?
  2. What role do electrolytes play?
  3. How does thermoregulation help?

Answer:
The player is experiencing dehydration. Electrolytes like sodium and potassium maintain fluid balance and nerve function. Thermoregulation helps maintain body temperature through sweating and vasodilation.

Case 5: Gymnast Performing a Somersault

A gymnast tucks her body while rotating in air and spins faster.

Questions:

  1. Which biomechanical principle explains this?
  2. What happens to angular velocity?
  3. What force acts downward?

Answer:
Conservation of angular momentum explains this. When she tucks in, her moment of inertia decreases, increasing angular velocity. Gravity acts downward throughout the motion.

Case 6: Basketball Player Jump Shot

A basketball player throws the ball at an angle toward the basket.

Questions:

  1. What type of motion is this?
  2. What angle gives maximum range?
  3. What factors affect the shot?

Answer:
This is projectile motion. A 45-degree angle gives maximum range under ideal conditions. Velocity of release, angle, height, and air resistance affect the shot.

Case 7: Wrestler Maintaining Balance

A wrestler bends knees and spreads legs while defending.

Questions:

  1. Why does this improve stability?
  2. What happens to centre of gravity?
  3. Define base of support.

Answer:
Bending knees lowers the centre of gravity and increases stability. The centre of gravity shifts downward. Base of support is the area between points of contact with the ground.

Case 8: Diabetic Athlete Before Competition

An athlete with diabetes checks blood sugar before running.

Questions:

  1. Which hormone regulates blood sugar?
  2. Why is regulation important?
  3. Which gland secretes this hormone?

Answer:
Insulin regulates blood sugar levels. Proper regulation prevents hypoglycemia or hyperglycemia during exercise. The pancreas secretes insulin.

Case 9: Cricketer Throwing a Ball

A cricketer rotates his shoulder forcefully to throw the ball fast.

Questions:

  1. What type of motion occurs at shoulder?
  2. Define angular motion.
  3. What increases torque?

Answer:
Angular motion occurs at the shoulder joint. Angular motion is movement around an axis. Increased force and longer lever arm increase torque.

Case 10: Long-Distance Cyclist

A cyclist maintains moderate speed for two hours.

Questions:

  1. Which energy system is dominant?
  2. Why is VO₂ max important?
  3. What adaptation occurs in trained athletes?

Answer:
The aerobic energy system is dominant. Higher VO₂ max allows greater oxygen utilization and endurance. Trained athletes develop higher stroke volume, efficient oxygen delivery, and improved muscular endurance

Here are 100 Assertion–Reason Questions with Answers from Human Physiology and Biomechanics (exam-oriented format).

🔹 Directions:

For each question, choose the correct option:
A. Both Assertion (A) and Reason (R) are true, and R is the correct explanation of A.
B. Both A and R are true, but R is not the correct explanation of A.
C. A is true, but R is false.
D. A is false, but R is true.

✅ Human Physiology (1–50)

1

A: Heart rate increases during exercise.
R: Working muscles require more oxygen.
Answer: A

2

A: Cardiac output increases during physical activity.
R: Stroke volume and heart rate both increase.
Answer: A

3

A: Oxygen debt occurs after intense exercise.
R: Extra oxygen is needed to remove lactic acid.
Answer: A

4

A: Aerobic respiration produces more ATP than anaerobic respiration.
R: Aerobic respiration uses oxygen completely to break down glucose.
Answer: A

5

A: Muscle fatigue occurs during prolonged exercise.
R: Lactic acid accumulates in muscles.
Answer: B

6

A: Hemoglobin transports oxygen in blood.
R: Hemoglobin contains iron.
Answer: A

7

A: Insulin lowers blood glucose level.
R: Insulin increases glucose uptake by cells.
Answer: A

8

A: Dehydration decreases athletic performance.
R: Water is essential for temperature regulation.
Answer: A

9

A: Sweating increases during high temperature.
R: Sweating helps in thermoregulation.
Answer: A

10

A: Reflex actions are faster than voluntary actions.
R: Reflex actions are controlled by spinal cord.
Answer: A

11

A: VO₂ max is an indicator of aerobic fitness.
R: It measures maximum oxygen utilization.
Answer: A

12

A: Stroke volume is higher in trained athletes.
R: Athlete’s heart becomes stronger with training.
Answer: A

13

A: Basal metabolic rate decreases with age.
R: Muscle mass decreases with age.
Answer: A

14

A: Adrenaline increases heart rate.
R: It prepares body for fight or flight.
Answer: A

15

A: Platelets help in blood clotting.
R: Platelets produce hemoglobin.
Answer: C

16

A: Nephrons filter blood in kidneys.
R: Kidneys regulate fluid balance.
Answer: B

17

A: Skeletal muscles are voluntary muscles.
R: They are controlled by somatic nervous system.
Answer: A

18

A: Tidal volume increases during exercise.
R: Breathing rate increases during exercise.
Answer: B

19

A: Lactic acid forms during anaerobic respiration.
R: Oxygen supply becomes insufficient.
Answer: A

20

A: Smooth muscles are involuntary.
R: They are found in internal organs.
Answer: B

(Continuing in same pattern…)

21

A: Cardiac muscle is striated.
R: It works without conscious control.
Answer: B

22

A: Homeostasis maintains internal balance.
R: It uses feedback mechanisms.
Answer: A

23

A: Calcium is essential for muscle contraction.
R: It exposes binding sites on actin.
Answer: A

24

A: Glycogen is stored in muscles.
R: It is used as energy source.
Answer: A

25

A: White blood cells fight infection.
R: They produce antibodies.
Answer: B

26

A: Vital capacity increases with training.
R: Lung efficiency improves with exercise.
Answer: A

27

A: Thermoregulation involves hypothalamus.
R: Hypothalamus controls body temperature.
Answer: A

28

A: Blood pressure rises during exercise.
R: More oxygen is required by muscles.
Answer: A

29

A: Motor unit consists of one neuron and muscle fibers.
R: It controls muscle contraction.
Answer: A

30

A: Endocrine glands release hormones into ducts.
R: Hormones travel through bloodstream.
Answer: D

31–50 (Condensed for readability)

31 A: ATP is energy currency. R: It stores energy in phosphate bonds. A
32 A: Parasympathetic system slows heart rate. R: It promotes relaxation. A
33 A: Diastolic pressure is lower value. R: It occurs during heart relaxation. A
34 A: Aerobic exercise improves endurance. R: It strengthens cardiovascular system. A
35 A: Muscle cramps occur due to dehydration. R: Electrolyte imbalance affects contraction. A
36 A: Thyroid regulates metabolism. R: It secretes thyroxine. A
37 A: Synapse transmits nerve impulses. R: Neurotransmitters are released. A
38 A: Anaerobic system provides quick energy. R: It does not require oxygen. A
39 A: Plasma carries nutrients. R: Plasma contains water. B
40 A: Cardiac output = HR × SV. R: Stroke volume is blood per beat. A
41 A: Oxygen binds to RBC. R: RBC contain hemoglobin. A
42 A: Glycolysis occurs in cytoplasm. R: It breaks glucose. A
43 A: Insulin deficiency causes diabetes. R: Glucose accumulates in blood. A
44 A: Athlete’s resting heart rate is low. R: Heart pumps efficiently. A
45 A: Shivering produces heat. R: Muscle contraction generates heat. A
46 A: Lungs contain alveoli. R: Alveoli help gas exchange. A
47 A: Fatigue reduces performance. R: Energy stores deplete. A
48 A: Hemoglobin increases in athletes. R: Oxygen transport improves. A
49 A: Smooth muscle is non-striated. R: It is voluntary. C
50 A: Nervous system maintains coordination. R: It sends impulses to muscles. A

✅ Biomechanics (51–100)

51

A: Force causes motion.
R: Motion is change in position.
Answer: B

52 A: Newton’s First Law is law of inertia. R: Objects resist change in motion. A
53 A: F=ma. R: Acceleration depends on force. A
54 A: Action-reaction forces act simultaneously. R: They are equal and opposite. A
55 A: Momentum = mass × velocity. R: Greater mass increases momentum. A
56 A: Friction opposes motion. R: It increases speed. C
57 A: Lower centre of gravity increases stability. R: It reduces imbalance. A
58 A: Wide base increases balance. R: Stability depends on base of support. A
59 A: Third-class lever gives speed advantage. R: Effort lies between fulcrum and load. A
60 A: Torque causes rotation. R: It depends on force and distance. A

61–100 (Condensed)

61 A Angular motion is rotation. R Around axis. A
62 A Linear motion is straight line. R No rotation. A
63 A Projectile motion affected by gravity. R Gravity pulls downward. A
64 A 45° gives max range. R Equal vertical & horizontal components. A
65 A Work = Force × distance. R Measured in Joules. B
66 A Power = Work/time. R Fast work = more power. A
67 A Kinetic energy = energy of motion. R Depends on velocity. A
68 A Potential energy stored. R Due to position. A
69 A Angular velocity rate of angle change. R Measured in rad/s. A
70 A Centripetal force inward. R Keeps object in circular path. A
71 A Centrifugal force outward. R Observed in rotation. A
72 A Mechanical advantage improves efficiency. R Load/effort ratio. A
73 A Stability improved by mass. R Greater mass resists change. A
74 A Reaction time important in sprint. R Faster start advantage. A
75 A Balance static or dynamic. R Depends on movement. A
76 A Sagittal plane divides left-right. R Movements like flexion occur. A
77 A Frontal plane divides front-back. R Abduction occurs here. A
78 A Transverse plane horizontal. R Rotation occurs here. A
79 A Axis perpendicular to plane. R Enables rotation. A
80 A Biceps curl third-class lever. R Effort between fulcrum & load. A
81 A Jumping requires force. R Force increases acceleration. A
82 A Sprinter pushes ground backward. R Ground pushes forward. A
83 A Lower friction reduces grip. R Grip needed in sports. A
84 A Torque increases with longer arm. R Distance increases turning effect. A
85 A Angular momentum conserved. R No external torque. A
86 A Tucking increases spin speed. R Reduces moment of inertia. A
87 A Stability decreases with height. R High COG unstable. A
88 A Wide stance improves balance. R Increases base area. A
89 A Throw speed affects range. R Velocity determines displacement. A
90 A Gravity acts downward. R Causes acceleration 9.8 m/s². A
91 A Impulse = Force × time. R Changes momentum. A
92 A Greater force increases jump height. R Produces higher acceleration. A
93 A Inertia depends on mass. R Heavy objects resist change. A
94 A Speed scalar quantity. R No direction. A
95 A Velocity vector quantity. R Has magnitude and direction. A
96 A Acceleration change in velocity. R Includes direction change. A
97 A Balance essential in gymnastics. R Prevents falling. A
98 A Proper posture reduces injury. R Distributes forces evenly. A
99 A Gait affects performance. R Efficient movement saves energy. A
100 A Biomechanics improves technique. R Analyzes forces & motion. A

✅ Overall Summary: Human Physiology and Biomechanics…….

🔹 Human Physiology

Human physiology is the study of how different systems of the body work individually and collectively to maintain life. The human body maintains a stable internal environment through a process called homeostasis. Homeostasis regulates body temperature, blood pressure, glucose levels, oxygen concentration, and pH balance. This regulation is controlled mainly by the nervous and endocrine systems through feedback mechanisms.

1️⃣ Circulatory System

The circulatory system consists of the heart, blood, and blood vessels. The heart is a muscular organ divided into four chambers: right atrium, right ventricle, left atrium, and left ventricle. It pumps deoxygenated blood to the lungs and oxygenated blood to the body.

Cardiac output, which is the amount of blood pumped per minute, is calculated as:

Cardiac Output = Heart Rate × Stroke Volume

During exercise, both heart rate and stroke volume increase to supply more oxygen and nutrients to working muscles. Athletes often have a lower resting heart rate because their heart pumps more efficiently.

Blood consists of plasma, red blood cells (RBCs), white blood cells (WBCs), and platelets. RBCs contain hemoglobin, which transports oxygen. WBCs provide immunity, and platelets help in blood clotting.

2️⃣ Respiratory System

The respiratory system enables breathing and gas exchange. Oxygen enters the lungs during inhalation and diffuses into the blood through alveoli. Carbon dioxide is removed during exhalation.

There are two main types of respiration:

  • Aerobic respiration – Uses oxygen to produce large amounts of ATP (energy).
  • Anaerobic respiration – Occurs without oxygen and produces less ATP along with lactic acid.

During high-intensity exercise, anaerobic respiration increases, which may cause muscle fatigue due to lactic acid accumulation. After exercise, the body requires extra oxygen to remove lactic acid—this is called oxygen debt.

3️⃣ Muscular System

The muscular system allows movement and maintains posture. There are three types of muscles:

  • Skeletal (voluntary)
  • Smooth (involuntary)
  • Cardiac (heart muscle)

Muscle contraction occurs through the sliding filament theory, where actin and myosin filaments slide past each other using ATP and calcium ions.

A motor unit consists of a motor neuron and the muscle fibers it controls. Efficient coordination of motor units improves strength and performance.

Muscle fatigue occurs due to energy depletion, lactic acid buildup, dehydration, or electrolyte imbalance. Proper training, nutrition, and rest improve muscular endurance.

4️⃣ Nervous System

The nervous system controls and coordinates body activities. It consists of:

  • Central Nervous System (brain and spinal cord)
  • Peripheral Nervous System (nerves)

The nervous system regulates voluntary movements, reflex actions, reaction time, and coordination. Reflex actions are faster because they are controlled by the spinal cord without brain involvement.

5️⃣ Endocrine System

The endocrine system includes glands such as the pituitary, thyroid, adrenal, and pancreas. These glands secrete hormones directly into the bloodstream. Hormones regulate metabolism, growth, reproduction, and stress response.

For example:

  • Insulin regulates blood sugar levels.
  • Adrenaline increases heart rate and prepares the body for emergencies.
  • Thyroxine controls metabolic rate.

Hormonal balance is crucial for maintaining homeostasis and physical performance.

6️⃣ Energy Systems in Exercise

The body uses three main energy systems:

  1. ATP-PC System – Provides quick energy for 0–10 seconds (sprinting).
  2. Anaerobic Glycolysis – Short-term energy with lactic acid production.
  3. Aerobic System – Long-duration energy production using oxygen.

Athletes train specific energy systems depending on their sport requirements.

🔹 Biomechanics

Biomechanics is the study of human movement using principles of physics and mechanics. It helps analyze posture, force, motion, and technique in sports.

1️⃣ Newton’s Laws of Motion

Biomechanics is based on Newton’s three laws:

  1. First Law (Inertia) – An object remains at rest or motion unless acted upon by force.
  2. Second Law (F = ma) – Force equals mass × acceleration.
  3. Third Law – Every action has an equal and opposite reaction.

For example, when a runner pushes against the ground, the ground pushes back, propelling the runner forward.

2️⃣ Force, Work, Power, and Energy

  • Force is a push or pull.
  • Work = Force × Distance.
  • Power = Work ÷ Time.
  • Energy can be kinetic (motion) or potential (stored).

In sports, explosive movements require high power output.

3️⃣ Levers in the Human Body

The body uses three types of levers:

  • First-class lever – Fulcrum between effort and load (neck movement).
  • Second-class lever – Load between fulcrum and effort (standing on toes).
  • Third-class lever – Effort between fulcrum and load (biceps curl).

Most body movements use third-class levers for speed and range of motion.

4️⃣ Centre of Gravity and Stability

The centre of gravity (COG) is the point where body weight is concentrated. Stability depends on:

  • Base of support
  • Height of COG
  • Body mass

Lower COG and wider base increase stability, which is important in wrestling and gymnastics.

5️⃣ Types of Motion

  • Linear motion – Straight-line movement
  • Angular motion – Rotation around an axis
  • Projectile motion – Motion under gravity (e.g., shot put)

In projectile motion, angle of release, velocity, and height affect range.

6️⃣ Planes and Axes of Movement

Movements occur in three planes:

  • Sagittal plane (flexion/extension)
  • Frontal plane (abduction/adduction)
  • Transverse plane (rotation)

Each plane has a corresponding axis of rotation.

7️⃣ Friction and Torque

  • Friction opposes motion but provides grip in sports.
  • Torque is rotational force and depends on force and distance from axis.

Understanding torque helps improve throwing and lifting techniques.

🔹 Importance in Sports and Daily Life

Human physiology explains how the body produces energy, circulates blood, contracts muscles, and maintains balance. Biomechanics explains how forces act on the body and how movement can be optimized.

Together, they:

  • Improve athletic performance
  • Prevent injuries
  • Enhance posture and coordination
  • Increase efficiency of movement
  • Support rehabilitation programs

🔹 Conclusion

Human Physiology and Biomechanics provide scientific knowledge about how the body functions and moves. Physiology focuses on internal processes such as respiration, circulation, and muscle contraction, while biomechanics applies mechanical principles to movement analysis. Their integration is essential for sports science, physical education, health promotion, and injury prevention. Understanding these concepts enables individuals to train effectively, maintain fitness, and achieve optimal physical performance.

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