Aerobic Endurance Training

Physiological Adaptations to Aerobic Endurance Training

Respiratory System

• Enhanced oxygen exchange in the lungs• Improved blood flow through lungs• Decreased submaximal respiratory rate:

– The number of breaths a person makes per minute. Average 12 breaths per minute (8 to 16 range).

• Decreased submaximal pulmonary ventilation:– the distribution of the air a person breathes

into the lung

Physiological Adaptations to Aerobic Endurance Training

Cardiovascular System

• Increased Cardiac Output: – Total volume of blood pumped by the

ventricle per minute, or simply the product of heart rate (HR) and stroke volume (SV)

– Stroke volume is the volume of blood, normally about 70 ml, ejected from the heart into the aorta during the contraction of the ventricles (systole).

Physiological Adaptations to Aerobic Endurance Training

• Increased blood volume and red blood cell number

• Increase in myoglobin

– Iron-containing, oxygen-carrying pigment present in muscle tissue

– It supplies oxygen to the muscle during strenuous exercise, when the muscle oxygen demands out paces the supply from the blood.

Physiological Adaptations to Aerobic Endurance Training

• Enhanced blood flow to skeletal muscles • Decrease in resting heart rate• Decrease in exercising heart rate • Improved thermoregulation (the regulating of

body temperature)• Increased insulin sensitivity• Increased lactate removal by organs-

increased lactate threshold, tolerance of high intensity effort

Physiological Adaptations to Aerobic Endurance TrainingMusculoskeletal System

• Increased mitochondrial size and density – Cell organelles that metabolize sugars

into energy = ATP

• Increased ATP, CP (creatine phosphate), and glycogen stores

• Increased oxidative enzyme concentration (specific proteins that act to speed up chemical reactions.)

Physiological Adaptations to Aerobic Endurance Training

• Increased capillarization in muscle bed

–The smallest blood vessels. Oxygen and nutrients leave the bloodstream through capillaries to get into the body

• Increased arteriovenous oxygen difference:

–Amount of oxygen extracted from transported blood

Factors Related to Aerobic Endurance Performance

• Maximal Aerobic Power (VO2Max)

• Lactate Threshold

• Exercise Economy

• Fuel Utilization

Maximal Aerobic Power (VO2 Max)• VO2 Max: maximum

volume of oxygen consumed by the body each minute during exercise

• Maximal Aerobic Power is a measure of a person’s capacity for aerobic ATP resynthesis

• There is a high correlation between VO2max and performance in aerobic endurance events.

Vo2 max Sport>75 ml/kg/min

Endurance Runners and Cyclists

65 ml/kg/minSquash

60-65 ml/kg/minFootball (male)

55 ml/kg/minRugby

50 ml/kg/minVolleyball (female)

50 ml/kg/minBaseball (male)

VO2 Max Tests

Lactate Threshold• Lactic Acid:

– A substance which forms in the muscles as a result of the incomplete breakdown of glucose (sugar)

– Associated with muscle fatigue and sore muscles

• The lactate threshold is that speed of movement or percentage of VO2 max at which specific blood lactate concentration begins to increase above resting levels

Factors Related to AerobicEndurance Performance

• Lactate Threshold

–In aerobic endurance events, the best competitor among athletes with similar VO2max values is typically the person who can sustain aerobic energy production at the highest percentage of his or her VO2max without accumulating large amounts of lactic acid in the muscle and blood.

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Lactate Threshold

• Elite endurance athletes typically have Lactate Threshold’s at or above 80% of VO2 max

• Values approaching 90% have been reported

• The lactate threshold is both responsive to training and influenced by genetics.

How to Improve Lactate Threshold

• Training –Results in a decrease in lactate

production at any given exercise intensity

–Untrained individuals usually reach the Lactate Threshold about 60% of VO2 max

– With training, Lactate Threshold can increase from 60% to above 70% or even higher

Maximal Lactate Steady State• Maximal lactate production is equal to

maximal lactate clearance within the body

• Better indicator of aerobic endurance performance than VO2 max and lactate threshold

• Aerobic endurance athletes must improve their lactate threshold or maximal lactate steady state

Exercise Economy

• A measure of the energy cost of an activity at a given speed (velocity)

• Example: swimmers using less oxygen

• As swimmers increase their speeds, more muscular effort is required, and more muscular by-products such as carbon dioxide and lactic acid are produced. This process induces fatigue in the muscles, and distance per stroke begins to decrease

Fuel Utilization

• Fat and carbohydrate are the fuels utilized during aerobic endurance exercise

• The degree to which each fuel acts as the primary or secondary source of energy depends on the prior nutrition of the athlete and the intensity and duration of the exercise

Fuel Utilization• At low to moderate levels of prolonged

exercise (50%-70% VO2 ) most energy needs come from fat and lesser energy needs come from carbohydrate

• At higher intensities (greater than 70% VO2 max) carbohydrates are utilized more than fat

• Protein plays only a minor role at very high levels of energy utilization, but adequate protein intake is critical for maintenance of lean body mass to enable exercise performance

The Myth of the “Fat-Burning” Zone• There is no magical “fat-

burning” zone for exercise

• Body fat reduction only takes place when there is more energy being burned than consumed

• This is known as the law of thermodynamics

• It is not how much fat an individual burns that ultimately dictates body fat reduction, it is how many calories burned!

Designing an Aerobic Endurance Program• Step 1: Exercise Mode

• Step 2: Training Frequency

• Step 3: Training Intensity

– Heart Rate

– Ratings of Perceived Exertion

– Talk Test

– Metabolic Equivalents

– Power Measurement

• Step 4: Exercise Duration

• Step 5: Exercise Progression

Designing an Aerobic Endurance Program

• Step 1: Exercise Mode (Type)– Exercise mode is the specific activity

performed by the client/athlete: cycling, running, swimming, and so on (specificity).

– Remember that the more specific the trainingmode is to the sport, the greater the improvement in performance.

• Example: your client who wishes to complete a 10K race, will spend time running on a treadmill or outdoors

Designing an Aerobic Endurance Program• Step 2: Training Frequency

– The number of training sessions conducted per day or per week.

– The frequency of training sessions will depend on the interaction of exercise intensity and duration, the training status of the athlete, and the specific sport season

• For general health requirements:– Everyday for short quantities of time

• For improved fitness levels:– 5-7 days per week

Designing an Aerobic Endurance Program

• Step 3: Training Intensity– Adaptations in the body are specific to the

intensity of the training session.

– High-intensity aerobic exercise increases cardio-vascular and respiratory function and allows for improved oxygen delivery to the working muscles.

– Increasing exercise intensity may also benefit skeletal muscle adaptations by affecting muscle fiber recruitment.

Designing an Aerobic Endurance Program

• Step 3: Training Intensity– Heart Rate

• The most frequently used method for prescribing aerobic exercise intensity

• Heart rate and oxygen consumption (VO2) are closely related

• During exercise, heart rate increases linearly with increases in workload which means an increase in oxygen

• The only way to determine a person’s true maximal heart rate (MHR) is to perform a graded exercise test that takes the client to the point where heart rate does not increase in workload

Target Heart Rate• Target heart rate range (THRR):

– Percent of APMHR– Karvonen Formula: related to the percent of APMHR,

except it allows for differences in resting heart rate (RHR)

• Heart rate reserve (HRR): – difference between a client’s maximal heart rate and his

or her resting heart rate– As a person becomes more fit and the RHR decreases,

the HRR will increase; a greater reserve to draw from– For improved fitness levels: 40-85% of heart rate reserve

(HRR) or 60-90% of maximal heart rate (HR max)

Target Heart Rate Calculations

• Percentage of Maximal Heart Rate Method

–Age-predicted maximum heart rate (APMHR) = 220 − age

–Target heart rate (THR) = (APMHR × exercise intensity)

–Do this calculation twice to determine the target heart rate range (THRR).

Table 18.1

Ratings of Perceived Exertion (RPE) Scale

• Designed to help clients monitor their exercise intensities through a ratings system that accounts for all of the body’s responses to a particular exercise intensity

• Not just a measure of how fast the heart is beating but includes respiration and emotional response to exercise

• Can be used as an approximation of heart rate to monitor a client’s heart rate

Ratings of Perceived Exertion (RPE) Scale

• 6-20 Scale: – Corresponds to an approximate heart rate by

multiplying the RPE by 10

– An RPE of 6 approximates a heart rate of 60 beats/min

• 0-10 Scale: – Not associated with a particular heart rate;

indicates how stressful the perceived exertion is above resting level, or how much harder the exercise is than a minimal level of exertion

Ratings of Perceived Exertion (RPE) Scale

• Regardless of which scale is used, the numerical ratings are associated with adjectives that describe the level of exertion

• May be used when heart rate intensity prescriptions are inaccurate due to medications, pregnancy, illness…

• A downside to using RPE’s is that they vary between clients and do not take individual differences into account

Talk Test• A client who is active at a light intensity level

should be able to sing while doing the activity

• A client who is active at a moderate intensity level should be able to carry on a conversation comfortably while engaging in the activity

• If a client becomes winded or too out of breath to carry on a conversation, the activity can be considered vigorous.

Metabolic Equivalents (METs)

• One MET is equal to 3.5 ml · kg–1 · min–1 of oxygen consumption and is considered the amount of oxygen required by the body at rest.

• 1 MET is equivalent to a metabolic rate of 1 kilocalorie per kilogram of body weight per hour

– Someone who weighs 160 pounds (72 kg) would burn approximately 70 calories an hour while sitting or sleeping.

• Any given MET level is an indication of how much harder than rest a particular activity is

Power Measurement

• Cyclists may use power-measuring cranks and hubs to regulate exercise intensity.

• Metabolic rate is closely related to mechanical power production.

Designing an Aerobic Endurance Program

• Step 4: Duration– Length of time of the training session

• For general health requirements:

–30 minutes per day

–This could be six five minute bouts

• For improved fitness levels:

–20-60 minutes per day

Key Point

• The duration of a training session is often influenced by the exercise intensity –The longer the exercise duration, the lower the exercise intensity

Health and Fitness Level Requirements• For general health requirements

– Use stairs– Park farther away– Mow the lawn with a push mower– Rake the leaves– Garden

• For improved fitness levels– Treadmill, stationary bike, stepper– Aerobics classes– Sports– Weight training

Designing an Aerobic Endurance Program

• Step 5: Exercise Progression– Progression of an aerobic endurance

program involves increasing the frequency, intensity, and duration.

– Frequency, intensity, or duration should not increase by more than 10% each week.

– When it is not feasible to increase frequency or duration, progression can occur with intensity manipulation.

– Progression of intensity should be monitored to prevent overtraining.

Types Aerobic Endurance Training Programs

• Long Slow Distance Training• Pace/Tempo Training• Interval Training• Repetition Training• Fartlek Training• Circuit Training• Cross Training

Long Slow Distance Training• Training is longer than race distance (or 30

minutes to 2 hours) at 70% of VO2max.

• Adaptations from this exercise include the following:

• Enhances the body’s ability to clear lactate• Chronic use of this type of training causes an eventual

shift of Type II fibers to Type I fibers

• Intensity is lower than that of competition, which may be a disadvantage if too much LSD training is used.– Mode: swimming, running, cross country skiing,

walking, biking…

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Sample LSD Training Program for a Marathon Runner

Pace/Tempo Training• Intensity at or slightly above competition intensity,

corresponding to the lactate threshold

– Steady pace/tempo training: 20 to 30 minutes of continuous training at the lactate threshold

– Intermittent pace/tempo training: series of shorter intervals with brief recovery periods

• Objectives

– Develop a sense of race pace and enhance the body’s ability to sustain exercise at that pace

– Improve running economy and increase lactate threshold

Pace/Tempo Training• Pace or Tempo Training

– Helps improve VO2 max– Stress the individual at a specific intensity and

improve energy production from both aerobic and anaerobic metabolism

– RPE of 13-14 on the 6-20 scale or 4-5 on the 0-10 scale

– Frequency: 1-2/week

Interval Training• Interval Training

– Exercise at an intensity close to VO2max for intervals of 3 to 5 minutes. Work to rest ratio should be 1:1

– This allows athletes to train at intensities close to VO2max for a greater amount of time

– It increases VO2max and enhances anaerobic metabolism

– Method should be used sparingly, and only when training athletes with a firm aerobic endurance training base

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Interval Training• Example: 3 minutes of high intensity running with 3

minutes of a light jog• Frequency is 1-2/week• Fatigue is the result• Is also great for clients who want to burn a maximum

amount of calories is the least amount of time

Repetition Training

• Conducted at intensities greater than VO2max, with work intervals lasting 30-90 seconds

• Work to rest ratio is about 1:5• Long recovery periods needed between

sessions• Frequency 1 x a week • Benefits include

– Improved running speed and economy– Increased capacity and tolerance for

anaerobic metabolism

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Sample Repetition Training Program for a Triathlete

Fartlek Training• Combines other methods of training (LSD and

Pace/Tempo)

• Easy running (~70% VO2max) combined with hillsor short, fast bursts (~85-90% VO2max)

• Can be adapted for cycling and swimming

• Benefits are likely to include:

– Enhanced VO2max

– Increased lactate threshold

– Improved running economy and fuel utilization

• Time: 20-60 minutes

• Frequency: 1/week

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Sample Fartlek Training Program for a Collegiate Cross-

Country Runner

Table 18.4

Key Point

• The various types of training induce different physiological responses. A sound program should incorporate all types of training into the athlete’s weekly, monthly, and yearly training schedule.

Other Types of Aerobic Endurance Training• Cross-Training

– Cross-training is a mode of training that can be used to maintain general conditioning in athletes during periods of reduced training due to injury or during recovery from a training cycle.

– Combining several exercise modes to aerobic endurance training

– For Example: 10 minute walk on a treadmill, 10 minute stationary biking and 10 minute on the elliptical trainer

– Help reduce overuse injuries• 10 minute walk on a treadmill, 10 minute

stationary biking and 10 minute on the elliptical trainer

Other Types of Aerobic Endurance Training

• Circuit Training– A series of resistance training exercises that

an individual performs, one after the other with minimal rest

– An example:• SB DB chest press• Standing cable row• Standing DB overhead shoulder press• Standing DB curl• Supine on SB DB triceps extension• Rest

Special Issues Related to Aerobic Endurance Training

• Detraining

– Occurs when the athlete/client reduces the training duration or intensity or stops training altogether due to a break in the training program, injury, or illness.

– In this absence of an appropriate training stimulus, the athlete experiences a loss of the physiological adaptations brought about by training.

Special Issues Related to Aerobic Endurance Training

• Tapering– Systematic reduction of training duration and

intensity combined with an increased emphasis on technique work, form and nutritional intervention.

– The objective of tapering the training regimen is to attain peak performance at the time of competition.

Special Issues Relatedto Aerobic Endurance Training

• Resistance Training– Research is limited, but some data suggest that

benefits can be derived from performing resistance training during aerobic endurance training.

– Benefits may include• Improvement in short-term exercise performance• Faster recovery from injuries• Prevention of overuse injuries and reduction of

muscle imbalances– It can improve hill climbing, bridging gaps between

competitors during breakaways, and the final sprint.

Enjoyment

• Amount of pleasure derived from the activity by the client

• Often overlooked by personal trainers

Postural Considerations• For clients with upper cross posture

(rounded head and forward shoulders)–During use of elliptical trainers, stationary

cycles, treadmills watch for rounding of shoulders and protruding head

–On steppers and treadmills, watch for grasping of the handles with an oversupinated or overpronated hand position which will cause elevated and protracted shoulders and protruding head

Postural Considerations–This equipment should be used

without assistance of hands to increase stabilization and burn more calories

–When a television is present, watch for excessive cervical extension or rotation of head to view the television

Postural Considerations• For clients with lower cross syndrome

(anterior pelvic tilt)– Bicycles or steppers may not be warranted,

hips are placed in a constant state of flexion adding to shortened hip flexors

– If bicycles or steppers are used, emphasize hip flexor stretches before and after use

– Treadmill speed should be kept to a controllable pace, to avoid overstriding which will cause the low back to arch, placing increased stress on the low back

Postural Considerations• For clients whose feet turn out and/or

knees move in– Ensure proper flexibility of the ankle joint

– Emphasize stretching the following muscles

• Gastrocnemius

• Soleus

• Hip adductors

• Tensor Fascia Latae and Iliotibial band

• Hip flexors