Post by RUBICON19 on Dec 28, 2008 13:09:55 GMT -5
HIT Interval training
The More We Learn, the Better We Work
Finding the most valuable exercise tool is a never-ending quest for fitness professionals.There are so many ways to exercise that it is often difficult for the general population to determine which program is most appropriate to achieve the best results. Fitness professionals have done a tremendous job providing various exercise opportunities to help reverse the country's wellness decline. At the same time, they have made great progress in an attempt to make exercise an enjoyable and permanent lifestyle change. There are classes ranging from hip-hop to Salsa to swinging seniors; numerous aquatic programs, personal training, military-style fitness; and resistance training with machines, tubes, bands, bars, chords and bells.
Virtually all movement can be considered exercise. In addition to the aforementioned fitness programs, there are also everyday examples of activity such as the post surgery patient standing for the first time to regain stability; the older adult tending a garden; and athleticism spanning from the weekend warrior to the worldclass athlete. In order to train any of these groups we must first realize that the common thread of all movement is the performance of work. While the diversity of ability is obviously huge in these scenarios, the fact that there is an energy requirement to facilitate a desired outcome is the basis of all physiological and biomechanical work. Regardless of the exercise, the secret to developing the training effect lies in the way we manipulate the energy systems and program the biomechanics of movement.
The good news is that physiological improvements can be made in all populations, and interval training can be the easiest, safest and most effective way to reach more individuals than any other exercise program. If a person is cleared by their physician to begin a training program, they can count on some level of result simply by adaptation if nothing else. That is just what the human body does: It responds to the stress put upon it based on the training environment. Fitness professionals have the job of making sure that the training environment is appropriate. This responsibility is not limited to class variations that range from beginning, intermediate and advanced, or military-style fitness vs. chair aerobics and so forth. Such variations allow individuals to decide what is appropriate for themselves. The responsibility lies within the training environment. This is the territory where they are held accountable for the prudent application of exercise science. And the interval training method is a fitness professional's most valuable tool for this endeavor.
The Historical Perspective
Interval training is the method of establishing a training effect by performing physiological and/or biomechanical work intermittently with periods of recovery. It is not new. As far back as the 1940s, Fartlek, a Swedish word meaning "speed play" was introduced in the United States. Fartlek is a relatively unscientific version of interval and continuous training demonstrated by interspersing sprinting with jogging. Emil Z?topek, from what is now the Czech Republic, used the interval method to train for the 1948 and 1952 Olympics. In addition to 18 world records, he is the only one to win the 5K, 10K and marathon in the same Olympics. It is believed that he ran beside a long row of trees. His work interval would be to sprint past as many trees as he could until he passed out. When he regained consciousness, his recovery interval would be completed and he would run until he passed out again. His measure of improvement was to gradually increase the number of trees he could pass. Of course this is certainly not a recommended protocol of interval training; however, one can gain an appreciation for the work-to-recovery ratio (W/R) from this eccentric example.
The Science of Interval Training
Interval training is based on the concept that more work can be performed at higher exercise intensities with the same or less fatigue compared to continuous training.2 The interval training recommendations are established on a work-torecovery ratio format with the following considerations: a) intensity of exercise; b) duration of the exercise interval; c) length of recovery; and d) number of repetitions of the work-recovery interval.1 The repeated bouts of exercise interspersed with recovery intervals can vary from a few seconds to several minutes or more depending on the desired outcome.3
Interval training has a sound basis in physiology and energy metabolism. In the case of a continuous run at a four-minute per mile pace, a large portion of energy would be supplied through anaerobic glycolysis. Within a minute or two, lactic acid levels would rise precipitously and the runner would become exhausted. During interval training, on the other hand, repeated bouts of around 10 seconds? duration would permit a severe load to be imposed without an appreciable buildup of lactic acid. This happens because the primary energy source for such brief exercise is the high-energy phosphates. Fatigue incurred during the predominantly "alactic" work interval would be minor and recovery would be rapid. The work interval could then begin again after only a brief rest period.1 Adaptive benefits to interval training include: a) the efficiencies in movement through optimal muscle fiber recruitment; b) increases in aerobic capacity through higher intensity and anaerobic work bouts; and c) increases in muscle capacity to tolerate lactic acid accumulation where aerobic training has no effect on the buffer potential. 4
Recent research has substantiated the benefits of a variety of interval training protocols. The research suggests that work-recovery ratios of 2:1 (30 seconds/15 seconds) at velocities associated with maximal oxygen uptake (VO2max) produce responses that benefit both aerobic and anaerobic energy system development.5 Another research study compared the effect of four training intensities on improvement in VO2max: long, slow distance running (45 minutes running at 70 percent HRmax); continuous running (25 minutes at lactate threshold, 85 percent HRmax); anaerobic interval (15 seconds/15 seconds, 47 reps at 90 to 95 percent HRmax); and a high-intensity aerobic interval (4 minutes/4 minutes running at 90 to 95 percent HRmax). The authors of this second test concluded that the anaerobic and the high-intensity aerobic intervals were superior in improving VO2max.6 Finally, a third study looked at the strength gains when manipulating the recovery interval. It was determined that too much rest, four minutes between sets, was not as effective as two minutes between sets of the squat exercise.7
A Word of Caution
For the most part, interval training has been associated with the young, competitive athletic population. Indeed, the research is clear as to the benefits of stressing the body at higher intensities with periods of recovery as opposed to continuous work at lower intensities. Some within the fitness industry have treated interval training as a new discovery, often calling it by trendy acronyms and abbreviations such as HIIT (high-intensity interval training) and SBT (short-burst training). Someone looking for the "latest workout buzz" must understand that it is necessary to prepare the individual properly and monitor the entire training program carefully due to the high potential for injury at such intense levels of work. The fitness profession is sometimes known to get overzealous for what are considered "new" ideas, when they have not investigated the scientific basis of the concept to fully understand its precise application.
Trainers who do not understand the ramifications of improperly planned, high-intensity exercise put their athletes and clients at risk of losing training days, competition opportunities or both, says Mike Henderson, MES, CPT, head personal trainer for the Alpert Jewish Community Center in Long Beach, Calif. "If trainers treat it like a new toy, they are likely to be unsuccessful in getting the best results and could even [hurt the person]. Stress fractures, bone bruises, fasciitis, iliotibial band syndrome, bursitis, muscle tears due to imbalance, tendonitis and, of course, classic overtraining syndrome can all rear an ugly head when sufficient assessment, adaptation and progression have not been practiced," Henderson says.
With interval training, as in other forms of physiologic conditioning, the intensity of exercise should be geared to the particular energy system to be trained. One research study identifies the three energy systems.8
Implementing the Interval Method
There are three aspects of physical training that can be developed by the interval method: neuromuscular, metabolic and strength. Neuromuscular training involves the skill component, which is the actual biomechanical patterning specific to the activity. Repetitive forehand strokes in tennis, for instance, will develop the motor pattern and training effect specific to the game. Metabolic training is the energy system utilized for the activity. The ATP-PC (Adenosine Triphosphate Phosphocreatine system) and lactic acid (LA) systems are considered anaerobic whereas the O2 system is aerobic. The strength aspect of physical training can also be included in an interval protocol. Circuit resistance training has been shown to provide significant strength gains9 while simultaneously enhancing the body's ability to repay the utilized energy.10
Interval Training Identified in Three Energy Systems
Energy System Intensity Time/Duration Work/Rest
(ATP-PC) Phosphagen system Maximal 1-10 seconds 1:3
(LA) Lactic Acid system Submaximal 1-3 minutes 1:2-1:3
Beta Oxidation or O2system Moderate 5 minutes 1:2-1:1
Based on this information the fitness professional can examine the facets of the activity to establish a preliminary plan. For example, a sprinter would require a great deal of work within the ATP-PC and LA systems depending on the distance. An individual competing in the 800 to 1,500 meters would shift to the LA and O2 systems.
Interval training is also beneficial for sporting events in which intensities vary and repeat many times over the course of a game, such as in tennis, soccer or volleyball. In these activities there must be a rapid repayment of the energy utilized in order for performance to continue. When planned properly both the neuromuscular and metabolic components can be trained simultaneously. Creatine phosphate and adenosine triphosphate are replenished and lactic acid is removed more rapidly when a training environment imposes demands within the work-recovery regimen of the interval method.11
Can Anyone Benefit From Interval Training?
It is important to realize that there is much more opportunity here than just training those with higher ability. Interval training is quite possibly the most valuable, yet underutilized, training method of all. Remember that this is a method of conditioning through which an individual performs a work bout for a given period of time, followed by a rest or recovery segment, also for a predetermined time period. Knowing that the variables of intensity, duration of the work and recovery segments, and repetitions can be manipulated to fit the needs and abilities of the individual renders interval training as highly versatile. It can effectively be used for rehabilitative purposes in the severely deconditioned population; individuals with metabolic disorders and overweight issues; as well as the entire aging demographic. High-intensity interval training involves significant anaerobic energy utilization and may better mimic the physiological requirements of activities in daily living.12 If the goal is to increase the ability to sustain tasks that are currently able to be performed, low- to moderate-intensity training is likely to be sufficient. But if the goal is to increase the ability to perform tasks that are above the current level of tolerance, higher-intensity training is likely needed.
A 2005 study found that interval training provides an effective means to improve the cardiovascular fitness and health status of highly functional patients with coronary artery disease.13 The study also revealed that interval training improves anaerobic tolerance to a greater extent than the traditional exercise training model without increasing risk to the patient. Another study compared moderate continuous training (70 percent peak heart rate) to aerobic interval training (95 percent peak heart rate) in patients from 64 to 86 years of age with post-infarction heart failure.14 VO2 peak increased more with the interval training (46 percent versus 14 percent, P<0.001) than the continuous training. Additional improvements occurring only with the interval training included a decline in left ventricular (LV) end-diastolic and end-systolic volumes, 35 percent increase in LV ejection fraction, improvement in endothelial function and an increase in mitochondrial function in lateral vastus muscle. Pulmonary rehabilitation incorporating exercise training is an effective method of enhancing physiological function and quality of life for patients with chronic obstructive pulmonary disease (COPD). Highintensity interval training is tolerable to these patients and may reduce the degree of dyspnea through a reduced ventilatory demand. If peak exercise tolerance is limited by a patient's ability to increase ventilation, it is possible that interval training at an intensity higher than peak will elicit greater muscular adaptation than an intensity at or below peak power on an incremental exercise test.12
We actually function in life by the interval training method. Human beings require a given amount of sleep after simply having performed several levels of work during the waking hours. In any given 24-hour period, for example, a person could be awake approximately 16 hours and require sleep for the remaining 8 hours. Consider this the lowest common denominator of work, and still be approximate to the work-to-recovery ratio of 3:1. Although the research is often geared toward higher intensity as measured by heart rate, remember one person's ceiling is another person's floor. A work interval can be defined according to various circumstances. An older person who is simply deconditioned will likely fatigue more quickly than a younger person. Rate of perceived exertion (RPE) is a better gauge than heart rate for this situation. Recovery can be determined subjectively and monitored to determine a safe repeat of the work interval. The key is the assessment of the individual with objectives and goals created. If the assessment of the current level of condition and ability is sound, the exercise professional who understands the interval training concept can establish a training effect for virtually any population.
Gregory L. Welch, MS, is an exercise physiologist and president of SpeciFit, An Agency of Wellnesslocated in Seal Beach, Calif. He is recognized nationally as a lecturer and author dealing with the special-needs population. Welch also established the SpeciFit Foundation, a nonprofit entity to promote wellness for women.
REFERENCES
MCARDLE, W., ET AL. EXERCISE PHYSIOLOGY, ENERGY NUTRITION AND HUMAN PERFORMANCE.BALTIMORE: WILLIAMS & WILKINS, 1996.
STONE, M.H. AND M.S. CONLEY. BIOENERGETICS: ESSENTIALS OF STRENGTH TRAINING AND CONDITIONING.CHAMPAIGN: HUMAN KINETICS, 1994.
DANIELS, J. AND N. SCARDINIA. "INTERVAL TRAINING AND PERFORMANCE." SPORTS MEDICINE,1 (1984): 327.
WILMORE, J.H. AND D.L. COSTILL. PHYSIOLOGY OF SPORT AND EXERCISE. CHAMPAIGN: HUMAN KINETICS, 1999.
ROZENEK, R., ET AL. "PHYSIOLOGICAL RESPONSES TO INTERVAL TRAINING SESSIONS AT VELOCITIES ASSOCIATED WITH VO2MAX." THE JOURNAL OF STRENGTH CONDITIONING RESEARCH, 21, NO. 1 (FEB 2007): 188-92.
HELGERUD, J., ET AL. "AEROBIC HIGH-INTENSITY INTERVALS IMPROVE VO2MAX MORE THAN MODERATE TRAINING." MEDICINE AND SCIENCE IN SPORTS AND EXERCISE, 39, NO. 4 (2007): 665-671.
WILLARDSON, J.M. AND L.N. BURKETT. "THE EFFECT OF DIFFERENT REST INTERVALS BETWEEN SETS ON VOLUME COMPONENTS AND STRENGTH GAINS." STRENGTH AND CONDITIONING RESEARCH, 22, NO. 1 (JAN 2008): 46-52.
MATHEWS, D.K. AND E.L. FOX. THE PHYSIOLOGICAL BASIS OF PHYSICAL EDUCATION AND ATHLETICS.PHILADELPHIA: W.B. SAUNDERS, 1976.
FLECK, S.J. AND W.J. KRAEMER. DESIGNING RESISTANCE TRAINING PROGRAMS. CHAMPAIGN: HUMAN KINETICS, 1987.
BALLOR, D.L., ET AL. "PHYSIOLOGICAL RESPONSES TO NINE DIFFERENT EXERCISES, REST PROTOCOLS." MEDICINE AND SCIENCE IN SPORTS AND EXERCISE, 21, NO. 1 (FEB 1989): 90-95.
GASSER, G.A. AND G.A. BROOKS. "METABOLISM OF LACTATE FROM PROLONGED EXERCISE TO EXHAUSTION." MEDICAL SCIENCE SPORTS,1 (1979): 76.
BUTCHER, S.J. AND R.I. JONES. "THE IMPACT OF EXERCISE TRAINING INTENSITY ON CHANGE IN PHYSIOLOGICAL FUNCTION IN PATIENTS WITH CHRONIC OBSTRUCTIVE PULMONARY DISEASE." SPORTS MEDICINE,36, NO. 4 (2006): 307-325.
WARBURTON, D.E., ET AL. "EFFECTIVENESS OF HIGH-INTENSITY INTERVAL TRAINING FOR THE REHABILITATION OF PATIENTS WITH CORONARY ARTERY DISEASE." AMERICAN JOURNAL OF CARDIOLOGY, 95, NO. 9 (MAY 2005): 1080-4.
WISLOFF, U., ET AL. "SUPERIOR CARDIOVASCULAR EFFECT OF AEROBIC INTERVAL TRAINING VERSUS MODERATE CONTINUOUS TRAINING IN HEART FAILURE PATIENTS: A RAMDOMIZED STUDY." CIRCULATION,115, NO. 24 (JUN 2007): 3086-94.
The More We Learn, the Better We Work
Finding the most valuable exercise tool is a never-ending quest for fitness professionals.There are so many ways to exercise that it is often difficult for the general population to determine which program is most appropriate to achieve the best results. Fitness professionals have done a tremendous job providing various exercise opportunities to help reverse the country's wellness decline. At the same time, they have made great progress in an attempt to make exercise an enjoyable and permanent lifestyle change. There are classes ranging from hip-hop to Salsa to swinging seniors; numerous aquatic programs, personal training, military-style fitness; and resistance training with machines, tubes, bands, bars, chords and bells.
Virtually all movement can be considered exercise. In addition to the aforementioned fitness programs, there are also everyday examples of activity such as the post surgery patient standing for the first time to regain stability; the older adult tending a garden; and athleticism spanning from the weekend warrior to the worldclass athlete. In order to train any of these groups we must first realize that the common thread of all movement is the performance of work. While the diversity of ability is obviously huge in these scenarios, the fact that there is an energy requirement to facilitate a desired outcome is the basis of all physiological and biomechanical work. Regardless of the exercise, the secret to developing the training effect lies in the way we manipulate the energy systems and program the biomechanics of movement.
The good news is that physiological improvements can be made in all populations, and interval training can be the easiest, safest and most effective way to reach more individuals than any other exercise program. If a person is cleared by their physician to begin a training program, they can count on some level of result simply by adaptation if nothing else. That is just what the human body does: It responds to the stress put upon it based on the training environment. Fitness professionals have the job of making sure that the training environment is appropriate. This responsibility is not limited to class variations that range from beginning, intermediate and advanced, or military-style fitness vs. chair aerobics and so forth. Such variations allow individuals to decide what is appropriate for themselves. The responsibility lies within the training environment. This is the territory where they are held accountable for the prudent application of exercise science. And the interval training method is a fitness professional's most valuable tool for this endeavor.
The Historical Perspective
Interval training is the method of establishing a training effect by performing physiological and/or biomechanical work intermittently with periods of recovery. It is not new. As far back as the 1940s, Fartlek, a Swedish word meaning "speed play" was introduced in the United States. Fartlek is a relatively unscientific version of interval and continuous training demonstrated by interspersing sprinting with jogging. Emil Z?topek, from what is now the Czech Republic, used the interval method to train for the 1948 and 1952 Olympics. In addition to 18 world records, he is the only one to win the 5K, 10K and marathon in the same Olympics. It is believed that he ran beside a long row of trees. His work interval would be to sprint past as many trees as he could until he passed out. When he regained consciousness, his recovery interval would be completed and he would run until he passed out again. His measure of improvement was to gradually increase the number of trees he could pass. Of course this is certainly not a recommended protocol of interval training; however, one can gain an appreciation for the work-to-recovery ratio (W/R) from this eccentric example.
The Science of Interval Training
Interval training is based on the concept that more work can be performed at higher exercise intensities with the same or less fatigue compared to continuous training.2 The interval training recommendations are established on a work-torecovery ratio format with the following considerations: a) intensity of exercise; b) duration of the exercise interval; c) length of recovery; and d) number of repetitions of the work-recovery interval.1 The repeated bouts of exercise interspersed with recovery intervals can vary from a few seconds to several minutes or more depending on the desired outcome.3
Interval training has a sound basis in physiology and energy metabolism. In the case of a continuous run at a four-minute per mile pace, a large portion of energy would be supplied through anaerobic glycolysis. Within a minute or two, lactic acid levels would rise precipitously and the runner would become exhausted. During interval training, on the other hand, repeated bouts of around 10 seconds? duration would permit a severe load to be imposed without an appreciable buildup of lactic acid. This happens because the primary energy source for such brief exercise is the high-energy phosphates. Fatigue incurred during the predominantly "alactic" work interval would be minor and recovery would be rapid. The work interval could then begin again after only a brief rest period.1 Adaptive benefits to interval training include: a) the efficiencies in movement through optimal muscle fiber recruitment; b) increases in aerobic capacity through higher intensity and anaerobic work bouts; and c) increases in muscle capacity to tolerate lactic acid accumulation where aerobic training has no effect on the buffer potential. 4
Recent research has substantiated the benefits of a variety of interval training protocols. The research suggests that work-recovery ratios of 2:1 (30 seconds/15 seconds) at velocities associated with maximal oxygen uptake (VO2max) produce responses that benefit both aerobic and anaerobic energy system development.5 Another research study compared the effect of four training intensities on improvement in VO2max: long, slow distance running (45 minutes running at 70 percent HRmax); continuous running (25 minutes at lactate threshold, 85 percent HRmax); anaerobic interval (15 seconds/15 seconds, 47 reps at 90 to 95 percent HRmax); and a high-intensity aerobic interval (4 minutes/4 minutes running at 90 to 95 percent HRmax). The authors of this second test concluded that the anaerobic and the high-intensity aerobic intervals were superior in improving VO2max.6 Finally, a third study looked at the strength gains when manipulating the recovery interval. It was determined that too much rest, four minutes between sets, was not as effective as two minutes between sets of the squat exercise.7
A Word of Caution
For the most part, interval training has been associated with the young, competitive athletic population. Indeed, the research is clear as to the benefits of stressing the body at higher intensities with periods of recovery as opposed to continuous work at lower intensities. Some within the fitness industry have treated interval training as a new discovery, often calling it by trendy acronyms and abbreviations such as HIIT (high-intensity interval training) and SBT (short-burst training). Someone looking for the "latest workout buzz" must understand that it is necessary to prepare the individual properly and monitor the entire training program carefully due to the high potential for injury at such intense levels of work. The fitness profession is sometimes known to get overzealous for what are considered "new" ideas, when they have not investigated the scientific basis of the concept to fully understand its precise application.
Trainers who do not understand the ramifications of improperly planned, high-intensity exercise put their athletes and clients at risk of losing training days, competition opportunities or both, says Mike Henderson, MES, CPT, head personal trainer for the Alpert Jewish Community Center in Long Beach, Calif. "If trainers treat it like a new toy, they are likely to be unsuccessful in getting the best results and could even [hurt the person]. Stress fractures, bone bruises, fasciitis, iliotibial band syndrome, bursitis, muscle tears due to imbalance, tendonitis and, of course, classic overtraining syndrome can all rear an ugly head when sufficient assessment, adaptation and progression have not been practiced," Henderson says.
With interval training, as in other forms of physiologic conditioning, the intensity of exercise should be geared to the particular energy system to be trained. One research study identifies the three energy systems.8
Implementing the Interval Method
There are three aspects of physical training that can be developed by the interval method: neuromuscular, metabolic and strength. Neuromuscular training involves the skill component, which is the actual biomechanical patterning specific to the activity. Repetitive forehand strokes in tennis, for instance, will develop the motor pattern and training effect specific to the game. Metabolic training is the energy system utilized for the activity. The ATP-PC (Adenosine Triphosphate Phosphocreatine system) and lactic acid (LA) systems are considered anaerobic whereas the O2 system is aerobic. The strength aspect of physical training can also be included in an interval protocol. Circuit resistance training has been shown to provide significant strength gains9 while simultaneously enhancing the body's ability to repay the utilized energy.10
Interval Training Identified in Three Energy Systems
Energy System Intensity Time/Duration Work/Rest
(ATP-PC) Phosphagen system Maximal 1-10 seconds 1:3
(LA) Lactic Acid system Submaximal 1-3 minutes 1:2-1:3
Beta Oxidation or O2system Moderate 5 minutes 1:2-1:1
Based on this information the fitness professional can examine the facets of the activity to establish a preliminary plan. For example, a sprinter would require a great deal of work within the ATP-PC and LA systems depending on the distance. An individual competing in the 800 to 1,500 meters would shift to the LA and O2 systems.
Interval training is also beneficial for sporting events in which intensities vary and repeat many times over the course of a game, such as in tennis, soccer or volleyball. In these activities there must be a rapid repayment of the energy utilized in order for performance to continue. When planned properly both the neuromuscular and metabolic components can be trained simultaneously. Creatine phosphate and adenosine triphosphate are replenished and lactic acid is removed more rapidly when a training environment imposes demands within the work-recovery regimen of the interval method.11
Can Anyone Benefit From Interval Training?
It is important to realize that there is much more opportunity here than just training those with higher ability. Interval training is quite possibly the most valuable, yet underutilized, training method of all. Remember that this is a method of conditioning through which an individual performs a work bout for a given period of time, followed by a rest or recovery segment, also for a predetermined time period. Knowing that the variables of intensity, duration of the work and recovery segments, and repetitions can be manipulated to fit the needs and abilities of the individual renders interval training as highly versatile. It can effectively be used for rehabilitative purposes in the severely deconditioned population; individuals with metabolic disorders and overweight issues; as well as the entire aging demographic. High-intensity interval training involves significant anaerobic energy utilization and may better mimic the physiological requirements of activities in daily living.12 If the goal is to increase the ability to sustain tasks that are currently able to be performed, low- to moderate-intensity training is likely to be sufficient. But if the goal is to increase the ability to perform tasks that are above the current level of tolerance, higher-intensity training is likely needed.
A 2005 study found that interval training provides an effective means to improve the cardiovascular fitness and health status of highly functional patients with coronary artery disease.13 The study also revealed that interval training improves anaerobic tolerance to a greater extent than the traditional exercise training model without increasing risk to the patient. Another study compared moderate continuous training (70 percent peak heart rate) to aerobic interval training (95 percent peak heart rate) in patients from 64 to 86 years of age with post-infarction heart failure.14 VO2 peak increased more with the interval training (46 percent versus 14 percent, P<0.001) than the continuous training. Additional improvements occurring only with the interval training included a decline in left ventricular (LV) end-diastolic and end-systolic volumes, 35 percent increase in LV ejection fraction, improvement in endothelial function and an increase in mitochondrial function in lateral vastus muscle. Pulmonary rehabilitation incorporating exercise training is an effective method of enhancing physiological function and quality of life for patients with chronic obstructive pulmonary disease (COPD). Highintensity interval training is tolerable to these patients and may reduce the degree of dyspnea through a reduced ventilatory demand. If peak exercise tolerance is limited by a patient's ability to increase ventilation, it is possible that interval training at an intensity higher than peak will elicit greater muscular adaptation than an intensity at or below peak power on an incremental exercise test.12
We actually function in life by the interval training method. Human beings require a given amount of sleep after simply having performed several levels of work during the waking hours. In any given 24-hour period, for example, a person could be awake approximately 16 hours and require sleep for the remaining 8 hours. Consider this the lowest common denominator of work, and still be approximate to the work-to-recovery ratio of 3:1. Although the research is often geared toward higher intensity as measured by heart rate, remember one person's ceiling is another person's floor. A work interval can be defined according to various circumstances. An older person who is simply deconditioned will likely fatigue more quickly than a younger person. Rate of perceived exertion (RPE) is a better gauge than heart rate for this situation. Recovery can be determined subjectively and monitored to determine a safe repeat of the work interval. The key is the assessment of the individual with objectives and goals created. If the assessment of the current level of condition and ability is sound, the exercise professional who understands the interval training concept can establish a training effect for virtually any population.
Gregory L. Welch, MS, is an exercise physiologist and president of SpeciFit, An Agency of Wellnesslocated in Seal Beach, Calif. He is recognized nationally as a lecturer and author dealing with the special-needs population. Welch also established the SpeciFit Foundation, a nonprofit entity to promote wellness for women.
REFERENCES
MCARDLE, W., ET AL. EXERCISE PHYSIOLOGY, ENERGY NUTRITION AND HUMAN PERFORMANCE.BALTIMORE: WILLIAMS & WILKINS, 1996.
STONE, M.H. AND M.S. CONLEY. BIOENERGETICS: ESSENTIALS OF STRENGTH TRAINING AND CONDITIONING.CHAMPAIGN: HUMAN KINETICS, 1994.
DANIELS, J. AND N. SCARDINIA. "INTERVAL TRAINING AND PERFORMANCE." SPORTS MEDICINE,1 (1984): 327.
WILMORE, J.H. AND D.L. COSTILL. PHYSIOLOGY OF SPORT AND EXERCISE. CHAMPAIGN: HUMAN KINETICS, 1999.
ROZENEK, R., ET AL. "PHYSIOLOGICAL RESPONSES TO INTERVAL TRAINING SESSIONS AT VELOCITIES ASSOCIATED WITH VO2MAX." THE JOURNAL OF STRENGTH CONDITIONING RESEARCH, 21, NO. 1 (FEB 2007): 188-92.
HELGERUD, J., ET AL. "AEROBIC HIGH-INTENSITY INTERVALS IMPROVE VO2MAX MORE THAN MODERATE TRAINING." MEDICINE AND SCIENCE IN SPORTS AND EXERCISE, 39, NO. 4 (2007): 665-671.
WILLARDSON, J.M. AND L.N. BURKETT. "THE EFFECT OF DIFFERENT REST INTERVALS BETWEEN SETS ON VOLUME COMPONENTS AND STRENGTH GAINS." STRENGTH AND CONDITIONING RESEARCH, 22, NO. 1 (JAN 2008): 46-52.
MATHEWS, D.K. AND E.L. FOX. THE PHYSIOLOGICAL BASIS OF PHYSICAL EDUCATION AND ATHLETICS.PHILADELPHIA: W.B. SAUNDERS, 1976.
FLECK, S.J. AND W.J. KRAEMER. DESIGNING RESISTANCE TRAINING PROGRAMS. CHAMPAIGN: HUMAN KINETICS, 1987.
BALLOR, D.L., ET AL. "PHYSIOLOGICAL RESPONSES TO NINE DIFFERENT EXERCISES, REST PROTOCOLS." MEDICINE AND SCIENCE IN SPORTS AND EXERCISE, 21, NO. 1 (FEB 1989): 90-95.
GASSER, G.A. AND G.A. BROOKS. "METABOLISM OF LACTATE FROM PROLONGED EXERCISE TO EXHAUSTION." MEDICAL SCIENCE SPORTS,1 (1979): 76.
BUTCHER, S.J. AND R.I. JONES. "THE IMPACT OF EXERCISE TRAINING INTENSITY ON CHANGE IN PHYSIOLOGICAL FUNCTION IN PATIENTS WITH CHRONIC OBSTRUCTIVE PULMONARY DISEASE." SPORTS MEDICINE,36, NO. 4 (2006): 307-325.
WARBURTON, D.E., ET AL. "EFFECTIVENESS OF HIGH-INTENSITY INTERVAL TRAINING FOR THE REHABILITATION OF PATIENTS WITH CORONARY ARTERY DISEASE." AMERICAN JOURNAL OF CARDIOLOGY, 95, NO. 9 (MAY 2005): 1080-4.
WISLOFF, U., ET AL. "SUPERIOR CARDIOVASCULAR EFFECT OF AEROBIC INTERVAL TRAINING VERSUS MODERATE CONTINUOUS TRAINING IN HEART FAILURE PATIENTS: A RAMDOMIZED STUDY." CIRCULATION,115, NO. 24 (JUN 2007): 3086-94.
