Cardiorespiratory Endurance

Principles of Exercise Training

• Reversibility dictates that fitness improvements are lost if exercise is discontinued.
• Detraining begins approximately 72 hours after ceasing exercise.
• Variation involves changing the stimuli to the body to continue seeing results.
• Individualization requires training programs to be customized to the individual’s needs and goals.

Designing an Exercise Program

• Exercise Prescription (ExRx) is more readily followed than a program.
• Programs should include an individualized amount of exercise.
• Programs should promote physical activity and achieve benefits.
• Programs should include fitness goals, a mode of exercise, and a warm-up.

Warm-up

• A warm-up should always start a workout and last 5-15 minutes.
• Warm ups should consist of low to moderate intensity exercises that progressively increase in intensity.
• Warm ups should be whole-body movements or exercise specific to prep the body.
• Warm ups increase muscle temperature, vasodilation, and heart rate.

Workout

• Use the F.I.T.T Principle, assessing Frequency, Intensity, Time and Type of exercise

Cool-down

• A cool-down should be very low intensity to clear out exercise metabolites built up during the workout.
• The purpose of a cool-down is to lower body temperature.
• The purpose of a cool-down is to get blood back to the heart.
• The purpose of a cool-down is to prevent blood pooling.

Exercise Considerations

• Too much exercise can lead to injury and increase the chances of getting sick.
• Prolonged sitting (>10 hours/day) poses more negative health risks than smoking.
• Taking breaks may reduce the risks of numerous diseases.
• Prolonged sitting outweighs the benefits of exercise.

Current Guidelines for Adults (18-64)

• Engage in 150 minutes of moderate-intensity.
• Engage in 75 minutes of vigorous-intensity exercise per week.
• A mix of moderate and vigorous-intensity can also be done.
• The minimum threshold for health benefits is 30 minutes most days of the week.

Barriers to Physical Activity

• Common barriers include lack of time.
• Common barriers include lack of motivation and commitment.

Cardiorespiratory Fitness (CRF/CRE)

• CRE involves the ability to perform aerobic exercise for a prolonged period.
• Benefits of CRE include increased energy expenditure (EE).
• Benefits of CRE include weight loss.
• Benefits of CRE include decreased cardiovascular disease (CVD) risk.
• Aerobic fitness is measured through VO2 max, the gold standard measurement of CRE.
• VO2 max measures the maximal amount of oxygen the body can consume and utilize during exercise.
• VO2 max measures cardiorespiratory fitness.
• VO2 max = cardiac output x arteriovenous difference.
• VO2 max = Q x A-VO2 diff (acronym).
• Cardiac output = Heart Rate (HR) * Stroke Volume (SV)

Cardiorespiratory System

• The cardiorespiratory system equals the cardiovascular system combined with the respiratory system.
• The system involves the heart, blood vessels, lungs, and muscles.
• The heart has "two pumps in one".
• The right side pumps oxygen-depleted blood to the lungs or back to the heart (pulmonary circuit).
• The left side pumps oxygen-rich blood to tissues (systemic circuit).
• Arteries carry oxygen-rich blood away from the heart (systemic circuit).
• Veins carry oxygen-depleted blood back to the heart (pulmonary circuit).
• Exception: Pulmonary artery and pulmonary vein.
• The respiratory system involves the lungs.
• Exhalation releases carbon dioxide.
• Inhalation allows oxygen to enter the lungs.
• Alveoli are tiny air sacs that allow for rapid gaseous exchange.

Energy Production

• Energy is the fuel needed to make the muscle move for activity fuel by breaking down foods.
• The breakdown of food releases biochemical compound called Adenosine Triphosphate (ATP).
• The body stores a small amount of ATP, so more must be produced.
• There are two ways to produce ATP: Anaerobic and Aerobic.

Anaerobic Energy Production

• Anaerobic system does not require oxygen.
• Aerobic system requires oxygen.
• High-energy phosphates (ATP-PC) are the fastest way to make but also the first to run out.
• ATP stores small amounts of energy lasting a few seconds.
• PCr (phosphocreatine) lasts 5-10 seconds is the fastest way to make ATP.
• More PCr is made by combining leftover ADP.
• Glycolysis is a process that breaks down carbs in cells.
• Blood glucose supplies the muscles.
• Glycogen (storage form of glucose) supplies the muscles.
• Most anaerobic ATP production comes from glycolysis, producing quick energy after the ATP-PC system
• If PCr runs out, the system stops, and then switches to glycolysis.

Anaerobic Energy Production

• Two main products include ATP(2) and Lactic Acid.

Aerobic Energy Production

• Energy begins to be generated from the aerobic system after one minute of exercise
• Continuously uses glycolysis.
• Carbohydrates, fats, and proteins can produce ATP.
• Gradual shifts from carbs to fats occur as a fuel source during prolonged exercise (>20 minutes).
• Protein can be used but it is spared as much as is possible.

Energy Continuum

• Everything is happening at the same time.
• Only the type of exercise being done changes.

Types of Exercise

• Many types of exercise use both systems.
• Anaerobic exercise dominates short-term activities requiring massive energy in a short time.
• Aerobic exercise dominates long-term activities using continuous energy.
• Soccer, basketball, and football are only 30% aerobic.

Acute Physiological Responses to Exercise

• They occur immediately during and after exercise, specifically aerobic.
• The need for oxygen increases.
• VO2 max = Cardiac output x arteriovenous difference.
• Q = Cardiac output
• VO2 max = Q * A-VO2 diff
• VO2 max = (HR * SV) * A-VO2 diff

Long Term Adaptations to Exercise

• Adaptations accrue over time with regular exercise, specifically aerobic.
• Decreased heart rate (HR).
• Increased stroke volume (SV) & cardiac output (Q).
• Increased VO2 max, respiratory abilities, and aerobic ATP production.

Evaluating CRE

• VO2 max test is the gold standard method.
• Field tests such as 1 mile walk, 1.5-2 mile run, and 6 minute walk are used.
• Cycle ergometer tests are also used.
• The amount of blood pumped per minute is cardiac output.
• Heart rate is the number of beats per minute.
• Stroke volume is the amount of blood ejected by the left ventricle per beat.

Muscular Fitness

• Muscular strength is the ability of a muscle to generate force.
• Muscular endurance is the ability to generate force over and over again.
• Muscular functionality is the ability to day to day functionality.
• Muscular strength and endurance can be maintained with strength and endurance training programs.
• Higher aerobic fitness means a lower risk for cardiorespiratory diseases.
• Resistance training may be better for weight loss than cardiorespiratory training.

Strength Training

• It reduces low back pain.
• It reduces joint and/or muscle injuries from physical activity.
• It delays and reduces age-related decreases in strength.
• It helps prevent osteoporosis.
• It improves ADL performance.
• Strength Training increases resting energy expenditure (also called resting metabolic rate).
• 1 pound of muscle can increase resting metabolic rate by 2-3%.
• 5 pounds of muscle can increase resting metabolic rate by ~10-15%.

Muscle Structure

• There are about 600 skeletal muscles in the body.
• Primary functions are to provide force for movement, maintain posture, and regulate body temperature.
• Movement of the body involves shortening and lengthening muscles.
• Fibers are long, thin cells.
• Fascia is a dense layer of connective tissue surrounding fibers.
• Tendons are connective tissue that attach muscle to bone.

Muscle Contraction

• Occurs via electrical signaling.
• A motor unit consists of a motor nerve and all the fibers it innervates.

Isotonic Exercise

• It involves the dynamic movement of a body part at a joint.
• Most exercises and sports are isotonic.
• It's performed in free motion and uncontrolled.
• There are 2 types of isotonic exercise, both common forms of human movement.
• Concentric: muscle shortens during movement against gravity or resistance.
• Eccentric: muscle lengthens during movement against gravity or resistance.

Muscle Exercise Classificiations

• Isometric (static exercise).
• Isometric uses muscle tension, but involves no movement.
• Isometric is a good way to develop strength after injury.
• Wall sits and planks are examples of isometric exercises.
• Isokinetic exercise is performed at a constant velocity.
• Isokinetic uses machines that provide resistance throughout the full range of motion.
• Isokinetic is very similar to isotonic but moves at the same rate.
• Slow-twitch fibers are Type 1 fibers.
• Type 1 fibers contract slowly.
• Type 1 fibers generate little force but resist fatigue.
• Type 1 are known for aerobic abilities and help us move for a long period of time.
• Fast-twitch fibers are Type IIx fibers.
• Type IIx fibers contract quickly.
• Type IIx fibers are the polar opposite of type 1.
• Type IIx fibers generate a lot of force but fatigue quickly.
• Intermediate fibers are Type IIa fibers.
• They serve as a combination of the other two types.
• They contract rapidly, produce great force, and resist fatigue.
• All the fibers are used equally within human movement.
• Muscle biopsy: Muscle biopsy tests occur somewhere in the calf or quads.

Fiber Recruitment

• Fiber recruitment is the process involving more muscle fibers to increase muscle force.
• Untrained individuals cannot recruit all muscle fibers and recruitment increases with training.
• During exercise, the order of fiber recruitment is fast to slow, and then slow to fast.
• Substantial changes to fiber type cannot be made, due to genetics.

Muscular Strength & Force

• Muscle size (primary factor) is directly related to the amount of force muscle can generate.
• The larger the muscle, the great the force produced.
• The number of muscle fibers recruited during a movement determines the amount of force.
• The more fibers that are stimulated, the greater the force generated.

Evaluating Muscular Strength

• Evaluate muscular strength through a muscular strength test.
• Evaluated through a 1 RM test (one repetition maximum).
• The 1 RM test measures the maximum amount of weight that can be lifted one time.
• The 1 RM test is for experienced weight lifters only.

Evaluating Muscular Endurance

• Push up test
• Sit up/ curl up test
• Sit to stand test

Training Principles

• Progressive overload is the amount of stress put on the body.
• Overload is done slowly by adding more weight, but not training to failure, and not feeling too fatigued.
• Progression should not exceed 10% of your overload.
• Specificity involves training specific types of range of motions.
• Specificity involves training the entire body (Muscle groups).
• Specificity will vary on intensity.
• Recuperation/recovery involves building time for the body to recover.
• Reversibility means if you don't use it, you'll lose it, so train consistently.
• Variation will require different exercises and variations.
• Individualization involves designing the exercise based on how one adapts.
• High resistance + low repetition = increased strength.
• Low resistance + high repetition = increased endurance.

Adaptations to Resistance Training

• Faster Fiber Recruitment (Neural Changes)
• Hypertrophy: increase in muscle size due to fiber size increase
• Hyperplasia: formation of new muscle fibers (Not Common/Unknown).
• Neural adaptation is one of the first adaptations within the first 10 days.
• Trained people have to adopt another physiological way to see further adaptations.
• Absolute strength: the maximum strength you have without accounting for anything.
• Men typically have the most absolute strength due to their DNA.

Safety Concerns

• Use spotters.
• Use collars on the ends of free weight bars.
• Don't drop weights.
• Always warm up prior to exercise.
• Breathe during exercises.
• Inhale while lowering the weight.
• Exhale while lifting the weight.
• Use slow movements.
• Start with light weights and work up gradually.

Exercise Prescription

• Exercise 2-3 days per week for resistance training.
• Allow 48 hours of rest before working the same muscle group.
• Base intensity on % of 1RM.
• Higher resistance = more strength gains

Time (Volume)

• Volume equals number of reps times the number of sets.
• Higher reps = endurance.
• Single vs multi set- 3 set is optimal.
• Freeweights, machines, bands, medicine balls, ropes, and tires.
• Be creative in your training but goal oriented.

Staying Motivated

• Make time to train regularly.
• Make training fun.
• Find a workout space or a facility you like.
• Develop a realistic routine.
• Plan a program that is challenging, but enjoyable.
• Work out with a friend or training partner.
• Remember the benefits of strength training: improved appearance, elevated self-esteem, metabolic rate, and well-being.
• Relative strength accounts strength relative to another physiological level, especially strength relative to your body weight.

Flexibility

• Flexibility involves everyday life, any movement that requires stretching, reaching, or twisting.
• Flexibility: is the ability to move joints freely through their full range of motion.

Five Structural Limitations to Movement

1. The shape of bones/type of joint (ball and socket vs hinge)
2. Stiff muscles
3. Connective tissues (ligaments & cartilage)
4. Tendons
5. Tight skin

Protecting Skeletal Muscle

• Two Muscle Protective Systems help prevent muscles from tearing and overall damage.
• Golgi Tendon Organs (GTO's). identifies tension in muscles.
• GTO's prevent muscles from trying to do something when they are not ready in order to not get hurt.
• GTO's relate to neural adaptation, which is the first thing that improves from resistance training.
• A GTO Tension connects muscle to bone.
• Muscle Spindles will ensure your body will contract when preventing muscles from ripping apart when stretched.
• Muscle spindles are activated when your muscle elongates.
• When your muscle elongates its called decentric.
• Stretch

Key benefits of Flexibility

• increased joint mobility: Prevents excessive tissue build up.
• Joint Lubrication reduces friction within the body.
• Reduces tension on muscles!
• More efficient body movement, as flexibility on one side of your body will ensure balance of mobility.

Good Posture

• Indicates that body is in alignment.
• Body is in alignment when there is the least amount of strain of positions.
• Bad posture occurs when the body falls out of alignment.
• Pain and damage will begin over time.
• Leads to pain/damage over time
• Good posture Prevents lower back pain (LBP)
• Good posture Benefits allows prevention of muscle fatigue, provides better appearance, minimizes joint wear and prevents arthritis.
• LBP is experienced by 80% of people at some point.
• LBP will cause 15% of Americans to be disabled in their lifetime.
• Chronic back pain lasts 6+ months
• Lordosis is caused by weak abs and hip flexors.

Flexibility Evaluation

• The sit and reach test measures ability to flex the trunk and mainly focuses on lower back muscles and hamstrings.
• The shoulder flexibility test measures range of motion at the shoulder.

Techniques to Increase Flexibility

• Implement Dynamic Stretches - this specifically works and stretches your joints within a range of motion in a pattern; should be slow and controlled.
• Static stretches are used as warmup based and not good to increase flexibility.
• Ballistic stretches are known as rapid and forceful behavior, involves taking joints in a very fast motion. Used before performance but not good to increase flexibility.
• Use static stretches to to mild discomfort to stretch it out. Best for overall flexibility.
• Use proprioceptive neuromuscular facilitation (pnf), the most effective training which involve doing a static stretch for 10-15 sec, then contract that same muscle groups for 3-5 secs.

FIIT Principle

• F: Most days of the week
• I: to the point of mild discomfort, NOT PAIN
• T: 15-30 seconds per stretch, >2 times per muscle
• T: Static, PNF, Dynamic, Ballistic

Avoiding Injuries

• Do not hold your breath. Breathe normally
• Do not fully extend the knee, neck, or back.
• Do not stretch muscles that are already stretched.
• Do not stretch to the point that joint pain occurs.
• Avoid overstretching when having someone assist you with passive stretches
• Avoid forceful extension and flexion of the spine.

Test your knowledge of cardiorespiratory endurance. Questions cover the benefits of exercise, recommended activity levels, barriers to physical activity, and the measurement and components of cardiorespiratory fitness, including VO2 max and cardiac output.