Fitness - Physical Fitness 2

Aerobic System Overview

  • Definition: Aerobic activities require oxygen to produce energy in cells.

  • Types of Aerobic Activities:

    • Aerobic Power

      • Involves high levels of oxygen usage over a moderate duration (e.g. 5-10 km races).

      • Typically lasts for 13 to 30 minutes.

      • Energy Source: Muscle glycogen from slow-twitch muscle fibers.

    • Aerobic Endurance

      • Involves using oxygen over longer durations (usually beyond 30 minutes).

      • Activities such as ultra marathons.

      • After glycogen depletion, the body taps into fat (muscle triglycerides, plasma fatty acids) and possibly proteins for energy.

Muscle Glycogen

  • Definition: Glycogen is a storage form of glucose.

  • Sources: Stored in the liver and muscles.

  • During aerobic power exercises, glycogen is broken down to glucose for energy.

Energy Utilization During Exercise

  • Preferred Energy Source: Body uses glucose before tapping into fat.

  • Aerobic Power vs. Endurance:

    • Power: Less than 30 minutes - uses glycogen primarily.

    • Endurance: More than 30 minutes - begins to utilize fat and protein after glycogen is depleted.

  • Fat as Energy: It yields more calories (9 kcal/g) compared to carbs/proteins (4 kcal/g), but conversion is slow and less efficient.

  • Common Misconceptions: Many avoid aerobic exercises like jogging, but numerous enjoyable alternatives exist (e.g. swimming, cycling).

Cardiovascular Fitness Recommendations

  • Minimum Requirements:

    • 3-5 times a week for at least 20 minutes.

    • Maintain heart rate between 60-85% of maximum.

  • Calculating Maximum Heart Rate: Subtract age from 220.

  • Example: A 20-year-old has a max heart rate of 200 bpm; training should be at 120-170 bpm for benefits.

Recovery Heart Rate

  • Measurement: Check heart rate immediately post-exercise and then after 1 minute. Subtract the second reading from the first.

  • Interpretation: Higher numbers indicate better cardiovascular fitness.

  • Post-Exercise Expectations: Be below 100 bpm after 10 minutes, back to resting heart rate within 30 minutes.

Anaerobic System Overview

  • Definition: Anaerobic activities do not require oxygen and mainly rely on glycolysis for energy.

  • Duration: High muscle force can be sustained for up to 2 minutes.

  • Key Energy Source: Muscle glycogen from fast-twitch muscle fibers.

  • Byproduct: Lactic acid accumulation leads to fatigue as it alters enzyme activity, diminishing energy production capacity.

Types of Anaerobic Exercise

  • Isotonics: Traditional weight training that challenges muscles through a full range of motion.

  • Isometrics: Muscle tension without movement (e.g. planks, wall sits).

  • Calisthenics: Bodyweight exercises that provide resistance through body mass (e.g. push-ups, sit-ups).

Recommendations for Anaerobic Exercise

  • Frequency: 10-20 minutes, 2-3 times per week, alongside aerobic activities.

  • Focus on Strength: Essential for overall fitness and daily tasks performance.

Training Approaches and Techniques

  • Muscle Endurance: Ability to perform continuous contractions.

  • Importance of repetition to enhance muscle learning and efficiency.

  • Concentric vs. Eccentric Phases:

    • Concentric: Muscle shortens during contraction.

    • Eccentric: Muscle lengthens while maintaining tension; focusing on this phase enhances muscle efficiency.

Strength and Power Training

  • Hypertrophy: Achieved through moderate reps (6-12) at higher weights.

  • Power Exercises: High-speed movements with lower reps to improve explosive force.

  • Strategy: Base training on individual goals; ensure enjoyment in routine to foster consistency.