Jack Hervert - PED 291 Chapter 14

For success in endurance activities, you need a highly trained aerobic energy system.

You also need to train your anaerobic system for activities of short bursts (linemen in football), and stop/go activities (hockey, basketball).

Reviewing our 3 energy systems:

a. ATP/PC (creatine)

b. Lactic acid (glycotic) system

c. Aerobic system

During physical activity, these 3 will contribute to the total energy requirement depending on exercise duration and intensity.

Immediate energy transfer (a golf swing) occurs anaerobic ally, almost all energy from high energy phosphates ATP and PCr.

For activities lasting up to 90 minutes (a 400 meter dash) -it's still mostly anaerobic, but it comes from b. the lactic acid (glycolysis-the breakdown of carbohydrates) formation that provides the energy. How much lactate you can make and tolerate determines how much energy is generated. This system can be trained to work very efficiently.

As exercise duration goes between 2 and 4 minutes: the energy from the anaerobic system decreases, and it begins to come from oxygen consuming reactions.

After 4 minutes: almost all energy comes from aerobic systems (Lipolysis-the breakdown of fatty acids).

Know the chart on page 359: figure 14.2

Training principles

1. Overload- exercising at a level above normal so body changes occur that improve efficiency> How?

a. the training frequency increases (times per week)

b. intensity

c. duration (time doing activity)

2. Specificity- training specific muscles required for the specific activity (the SAID principle). Page 359 has an excellent example.

The training overload of specific muscle groups improves performance and aerobic power by improving oxygen transport and utilization in the trained muscles.

Factor to variation in training responses among individuals: THE PERSON'S FITNESS LEVEL AT THE START OF TRAINING. All performers on a team don't start at the same level of fitness, so they cant all work at the same intensity level. Training programs must meet individual needs and capabilities.

3. Reversibility- after only a week, reductions occur in physiologic function and exercise capacity. Athletes should maintain some level of off season sport specific exercises to slow down the rate of deconditioning.

When someone is a. running a 400 meter dash or b. working on blocking skills as a football lineman: here is how the energy is provided and how we can train that person.

1. At the start (the first 6 seconds), the ATP and PCr system provides energy. You can train this by: A. sets of sprinting all out for 6-10 seconds, with 30-60 seconds of rest in between. B. sled blocking for up to 10 second intervals with the same rest recovery.

2. Now the Lactic acid (anaerobic energy from the activation of glycotic (carbohydrate) energy pathways) system provides energy after the first 6 seconds, for the next minute of so.

Training this system:

a. bursts of up to 60 seconds of intense running.

b. Sled drills for up to 30 seconds.

3-5 minutes of recovery between each one.

Every 60 second interval causes lactate stacking-when blood lactate levels continue to increase with each interval of work until exhaustion sets in.

AEROBIC TRAINING

For those of us who don't work out (sedentary): cardiovascular fitness is measured by blood pressure, heart rate, cholesterol levels, and body composition.

An elite athlete's cardiovascular fitness is measured by oxygen intake and utilization.

Children's fitness levels are tested by the one mile run (table 14.2, page 363).

A low heart rate during a workout of moderate intensity means each beat is pumping enough blood with oxygen to the active muscles.

In labs they do step tests to determine fitness levels, and it's proven that how quickly your heart beat returns to normal after the test (recovery heart rate) is a simple way to determine heart rate response to exercise stress.

Less than 20% of adults exercise regularly at sufficient intensity and duration levels to meet current guidelines of attaining fitness.

More than 60% of people who start programs don't maintain it.

2 goals of aerobic conditioning

1. improve the body's capacity to deliver oxygen

2. develop the muscles capacity to consume oxygen.

Factors that affect aerobic conditioning.

a. initial level of cardio respiratory fitness-improvement occurs if one's initial fitness is low. Someone in very good shape leaves little room of improvement. A 5% improvement for an elite athlete is more significant than a 25% increase for a sedentary person.

b. Frequency of training-3 times per week minimum.

c. Duration of training- 20-30 minutes each session. It can be a straight jog or 8-10 2 minute intervals of hard running.

d. Intensity of training-THE MOST CRITICAL FACTOR FOR SUCCESSFUL AEROBIC TRAINING because it reflects the activity's energy requirement for each minute, and the specific energy systems (remember we have 3) that are activated.

The most practical way to assess exercise intensity is by checking the exercise heart rate. For college age people to reach 130-140 beats per minute, or reach 70% of their maximum heart rate (220-age). This level of intensity represents the threshold stimulus (the minimum amount) to cardiovascular improvement. More intense exercise is more effective.

Conversational exercise- intense enough to stimulate a training effect yet not so strenuous that it limits a person ability to talk during the workout.

ADAPTATIONS TO EXERCISE TRAINING

Women and men show similar physiologic and metabolic adaptations to aerobic training.

A. Anaerobic system changes:

1. increased muscle levels of ATP/PCr (creatine) and glycogen storage.

2. increased number and activity of enzymes in fast muscle fibers that control the anaerobic phase (glycolysis) of glucose breakdown.

3. increased capacity to generate high blood lactate levels during maximum exercise.

B. Aerobic system changes-enhances a muscle fiber's capacity to generate ATP

1. increase in mitochondria size and number, which improves it's capacity to generate ATP by oxidative phosphorylation (how ATP forms). Use page 103 and the example of a waterfall to review this process.

2. increase in aerobic system enzymes goes along with the increased mitochondria size and number. Now an athlete can have a high aerobic capacity during exercise without accumulating excess lactic acid.

3. more fatty acids are oxidized (burned). This process (Lipolysis) results from greater blood flow in the trained muscles and a higher quantity of fat metabolizing enzymes. Now the athlete can work at a higher level with less fatigue from the burning of carbohydrates (glycogen). Another reason why we need to eat some fat.

4. Carbohydrate metabolism is increased because the mitochondria has better oxidative capacity and the increased amount of glycogen storage in the liver and muscles.

5. muscle fibers aerobic capacity and lactate threshold levels increase. The muscle fibers grow in size.

Cardiovascular adaptations

1. Heart size- aerobic training enlarges the heart by increasing the size of the ventricles and thickness of the heart walls (eccentric hypertrophy) which improves stroke volume. If training reduces the heart will return to the size that it was before training.

(sammy strongheart/willie weakheart)

2. plasma volume- up to 20% higher which increases circulation and increases oxygen delivery during exercise.

3. stroke volume- in shape people have a larger stroke volume ability (more blood is pumped per beat) See figure 14.12, page 372.

4. heart rate- lower in trained people because of the heart's larger stroke volume ability. As exercise intensity increases, an athletes heart rate speeds up to a lesser extent than untrained people.

5. cardiac output- THE MOST SIGNIFICANT CHANGE IN CARDIOVASCULAR FUNCTION WITH AEROBIC TRAINING-an increase in cardiac output results directly from improved stroke volume.

6. oxygen extraction- during exercise more oxygen is extracted (taken) from artery blood during exercise.

7. blood flow- distribution of blood increases to muscles because of:

a. increase in cardiac output

b. lack of blood flow to non active areas

c. increased mitochondria size and number within the trained muscle

8. blood pressure- systolic

----------

diastolic

both of these go down: but the systolic drops more.

The average drop is about 6-10 points.

Lowering your blood pressure is the first line of defense against hypertension.

Pulmonary adaptations

a. maximal exercise-with training, improvements in maximal oxygen uptake leads to increased exercise ventilation. Why? YOUR AEROBIC CAPACITY IMPROVES.

b. submaximal exercise-20 weeks of run training increases ventilatory muscle endurance by 16%. There is less lactate accumulated, and a reduced feeling of breathlessness and pulmonary discomfort.

Less air needs to be taken in so breathing frequency decreases. Air remains in the lungs for longer time intervals between breaths. More oxygen is captured to be used by the muscles.

An untrained person breaths out 17% of air, the trained person 14%.

In hot weather trained people have a larger blood plasma volume and are better responsive to heat. Their bodies also cool more efficiently.

Specificity factor-if you are doing an activity you don't do very often, your muscles don't use the air as efficiently.

Starting a program page 376

2 methods of training with exercise intensity for aerobic training:

1. training at a percentage of air taken in and used.

2. training at a percentage of your maximum heart rate. (220 -age: then take pulse during exercise)

While running it might be at 140: that is 70% of your maximum (this is recommended for a 20-30 minute time period), or you can do an activity at 120 for 45 minutes.

MORE IS NOT USUALLY BETTER

The rating of physical effort corresponds with exercise heart rate. All of us can learn to exercise at a specific level based on your feelings of exertion (listen to your body).

Continuous versus intermittent training

Long slow distance requires sustained steady rate aerobic exercise: great for people starting out.

Long slow distance can (without knowing) progress at a comfortable threshold level of 70% max heart rate and maybe higher. This activates mostly slow twitch fibers.

Elite distance runners will run for 45 minutes steady and then do 30-40 minutes of sprint intervals (intense activity with periods of low energy expenditure in between: this is like a lot of sport activities). The spacing of exercise and rest are important to training: to figure this out you can use your recovery heart rate as an indicator to determine if you need more rest. Interval training can be short (50 meters) or long (mile repeats).

I'm going to train for running a four minute mile in an 11 minute work period, by running at a four minute mile pace for 15 seconds and then resting for 30 seconds until I reach a mile (actually it takes 11 min. and 30 sec.).

The ideal aerobic workout-page 380

Relief interval training: for sprinters it's 1:3. Sprint 10 seconds, rest 30. For activities of 60-90 second work: rest is 90-120 seconds (1:1.5)

Maintaining fitness: if intensity is the same, training frequency and duration can decrease as much as two thirds. For example: 6 day a week training reduced to 2, and 40 minutes per day reduced to 13.