Physical Activity: Types, Health, and Skill-Related Fitness

• Physical Activity (PA) occurs through any bodily movement produced by contracting skeletal muscles.

Types of Physical Activity

• PA can be recreation/exercise, transport (walking, cycling, skating), occupation (manual labor), or household (carrying groceries, yard work).
• Ability to perform PA depends on health and skill.

Health-Related Fitness Impacted by PA

• Body composition, cardiorespiratory endurance, muscular strength/endurance, and flexibility.
• Supports day-to-day activities.

Skill-Related Fitness Impacted by PA

• Agility, coordination, reaction time, balance, speed, and power.
• Important for specific physical tasks/sports.
• American College of Sports Medicine (ACSM) promotes health and fitness through research, education, and certification.

ACSM Exercise Recommendations

• Aim for at least 150 minutes of moderate-intensity or 75 minutes of vigorous-intensity aerobic activity per week.
• Two minutes of moderate intensity equals one minute of vigorous intensity.
• Resistance exercises for major muscle groups at least two days per week.
• Less than 5% of adults meet these exercise recommendations.

Health Benefits of PA

• Reduced risk of prostate and breast cancer.
• Reduced risk of increased blood pressure and cardiovascular disease.
• Improved physical function and fitness after injury.
• Improved cognition and quality of life for mental disorders like schizophrenia, ADHD, and dementia.
• Better management of Type 2 diabetes.

Risks of PA

• Risk of sudden cardiac death, especially for sedentary individuals starting high-intensity exercise.
• PA should increase gradually, and exercises should match one’s fitness level.
• Cardiovascular Disease (CVD) signs and symptoms include shortness of breath during exercise, dizziness, chest pain, and irregular heartbeat.
• There’s an inverse relationship between CVD and PA: increased PA decreases CVD risk.

Musculoskeletal Injury

• Higher risk for those previously injured.
• Weight-bearing, repetitive motion, and team/contact sports can cause injury, stressing joints and muscles.

Screening Before Exercise

• A decision tree helps determine if someone needs medical clearance before starting an exercise program.
• PA includes 3 days a week, 30 minutes, at moderate intensity (40-60% HR reserve/VO2max; RPE 12-13).
• CMR disease includes heart attack, catheterization/angioplasty, defibrillator, or renal disease.
• Signs and symptoms include dyspnea at rest, ankle edema, intermittent claudication, or heart murmurs.

Identifying At-Risk Individuals

• Consider medical contraindications.
• Absolute contraindications: PA risks outweigh benefits (e.g., unstable angina, pulmonary infarction).
• Relative contraindications: PA benefits outweigh potential risks (e.g., mental impairment, uncorrected medical conditions).

Necessary Actions

• Medical/physical evaluation should be performed.
• Medically supervised physical activity may be required.
• Address health/medical concerns like unstable angina or sudden chest pain.
• Assess risk for future CVD (2+ risk factors).
• A positive screening result indicates higher CVD risk; a negative result is favorable.
• Screening Levels: Everyone in a PA program should be screened.
• A self-guided approach starts with a Physical Activity Readiness Questionnaire (PAR-Q).
• Professionally supervised approach includes physician/qualified professional evaluation and medical history assessment, with medical evaluation/clearance for high-risk clients.
• The main approach is to start with lower intensities and progress gradually, consulting a clinician if there are any doubts.

Cardiorespiratory Fitness (CRF)

• CRF or VO2max is the highest amount of oxygen a person can use during exercise, indicating the ability of the circulatory/respiratory system to supply oxygen to muscles.

Components of VO2

• Consumption (moving oxygen to lungs).
• Transport (moving red blood cells to skeletal muscle).
• Utilization (taking oxygen from red blood cells to make ATP).
• Higher CRF is desirable, showing how the transport and utilization systems are working efficiently
• There’s a dose-response relationship: improving one system improves VO2 (consistent exercise decreases disease).

Formulas

• VO2 max = Cardiac Output-max × (a-vO 2∆ diff max)
• Cardiac Output = Heart Rate x Stroke Volume

Stroke Volume

• The amount of blood ejected from the ventricle each cycle.
• The left ventricle drives blood from the heart vasculature (stroke volume).

Energy Systems vs. Work Time

• ATP-CP, Rapid Glycolysis, Aerobic
• ATP-CP provides energy for short, high-intensity activity (high initially, rapidly declines).
• Rapid Glycolysis provides energy for high-intensity, short-duration activities (longer than initial burst) where oxygen supply is limited.
• Aerobic system provides energy for long-duration, low-to-moderate intensity activities (increases gradually over time).

Oxygen Kinetics

• Deficit, Steady-State, and EPOC

Stages of Exercise

• At the start of exercise, the body relies on anaerobic metabolism (without oxygen), creating an O2 deficit.
• During the middle of exercise, aerobic metabolism (with oxygen) kicks in, leading to a steady state of O2 consumption.
• After exercise ceases, the body continues to consume oxygen at a higher rate to repay the oxygen debt (EPOC – excess post-exercise oxygen consumption).

Cardiovascular Response to Exercise

• a-νΟ2∆ (Arteriovenous Oxygen Difference) measures how much oxygen is extracted by the tissues from the blood during circulation.
• The bigger the difference, the more efficiently muscles are using oxygen.

Increase in Workload Impacts the Following

• HR increases
• Stroke Volume: initial increase (40-60% max), then plateaus
• Cardiac output increases
• Pulmonary Ventilation increases

HR Training Adaptation

• Continued training reduces resting HR (heart pumps more blood per beat, so it doesn't need to beat as often)

Blood Pressure Response

• Dynamic exercise (running/playing game) raises systolic BP but keeps diastolic BP stable.
• Static exercise (wall sit/plank) significantly raises both systolic and diastolic BP; static diastolic is higher.

BP During Exercise

• Systolic is higher due to pressure from constant heart contractions.
• Selecting CRF Assessments: Avoid “one size fits all".
• Intensity, expense of test, equipment/personnel needed; safety concerns; accuracy of results.

METs

• Metabolic Equivalent of Task
• 1 MET = The amount of oxygen consumed at rest (≈ 3.5 mL O2 per kg body weight per minute)
• 1L O2= 5kcal
• Light: <3.0 METS
• Moderate: 3-5.9 METS
• Heavy: >5.9 METS

FITT-VP

• Framework for exercise program.

Principles of Training

• Progressive Overload: increase volume/intensity to induce adaptation.
• Reversibility: “use it or lose it".
• Individual Difference: train for requirement of individ. ; same stimulus could have different responses (genetics play factor).
• Specificity: Specific exercises to adapt specific training skills.

Exercise Intensity

• Subjective: Talk test, rate of perceived exertion (borg scale: 6-20).
• Direct: VO2 max test, peak heart rate method.

Injury Factors with CRF

• Extrinsic factors include type/speed of movement, footwear, surfaces, and environment (air quality).
• Intrinsic factors include previous injury, strength/flexibility, and imbalances.

Weather/Environmental Effects

• Heat: Sweat loss and increased HR
• Quickly burn through glucose
• Altitude: “live high, train low”
• % oxygen is same at all altitudes

Learn about physical activity (PA), including its types (recreation, transport, occupation, household) and impact on health and skill-related fitness. Understand how PA supports daily activities and specific tasks. The lesson also covers ACSM exercise recommendations for weekly aerobic activity.