Q. What is the Ventilatory Threshold, Anaerobic Threshold, and how are these different than Lactate Threshold?
A. The Ventilatory Threshold (VT) is determined from ventilatory changes that reflect a trend change in your CO2 extraction, O2 consumption, and the breathing volume and rate. This trend change is often highly correlated with the lactate threshold. Both suggest a trend toward accelerated or accumulating fatigue problems. The Anaerobic Threshold (AT) refers also to a more fatiguing, non sustainable, level of exercise intensity where your body can no longer rely on utilizing fat and oxygen to maintain energy demands. The AT is determined when the RER exceeds 1.0 which is when 100% of your energy is now coming from carbohydrates. The assumptions are that VT and AT occur at very similar levels of intensity to the Lactate Threshold (LT). The LT is when lactate production becomes greater than lactate clearance, causing a buildup of lactate in the blood. Again, we can perform blood lactate testing to find this point but this involves frequent blood sampling throughout the test, with only a fraction of data points that are obtained from ventilator testing, and no "maximum fat burning" determination. It is your threshold characteristics that are by far the most informative and important information for evaluating the training effect
Thursday, February 24, 2011
Friday, February 18, 2011
Sustainable Pace: Field Test
For a runner to evaluate their training effect (TE) it is important to learn how to monitor their sustainable pace. The sustainable pace(s) is an intensity level that you can sustain w/out accelerating the release of fatigue related waist products and the acidosis that accumulates when you are training at or above the lactate threshold (LT). In the lab you can evaluate this effect by determining the changes in speed (or power) and oxygen consumption levels (VO2) at the Lactate or ventilatory thresholds. See Lactate Threshold.
Lab testing can distinguish how the runner has physiologically adapted to improve his or her sustainable pace since we can observe the actual changes in oxygen consumption (i.e., metabolic fitness). Where as, speed changes at LT could represent both the economy of motion changes as well as those metabolic fitness changes. Knowing this is important because without all that information we typically are only guessing if your fitness is lifting up your pace to it's potential. Even using time trial speeds or race results may not be the best indicators of how well your body is adapting to your training plan. Time trials (TT) rely on your fastest effort for 30-60 minutes which can represent; your effort, metabolic fitness, economy and anaerobic (above LT) endurance changes. This may work well for endurance events that last fewer than a couple of hours, however if your event requires longer efforts (i.e., marathons) the anaerobic component to the TT may not reflect how well you can actually sustain the sub-threshold paces involved in the longer races or efforts. Similarly, if you evaluate your TE by your races only you can't be sure if the slower than goal pace was due to poor pacing, weather, fueling, effort, dehydration, overtraining or low fitness.
Although lab testing is your best bet to evaluate your TE the feasibility of regular testing every month is low due to limiters like cost and logistics. Another option that can be included along with periodic lab testing is to evaluate sustainable pace by using a field test that can monitor your pace changes at a constant subthreshold heart rate. One way to do this is to choose a heart rate that is about 10 beats below your lactate threshold heart rate and then run a 1 mile time trial at that heart rate. If the mile time decreases at the targeted HR from test to test than your sustainable pace is improving. This is a relatively safe test as well as a great field test to determine your TE for races or events that take longer than 2-3 hours.
To start tracking your Sustainable Pace check out this tool: Sustainable Pace Tracker.
Lab testing can distinguish how the runner has physiologically adapted to improve his or her sustainable pace since we can observe the actual changes in oxygen consumption (i.e., metabolic fitness). Where as, speed changes at LT could represent both the economy of motion changes as well as those metabolic fitness changes. Knowing this is important because without all that information we typically are only guessing if your fitness is lifting up your pace to it's potential. Even using time trial speeds or race results may not be the best indicators of how well your body is adapting to your training plan. Time trials (TT) rely on your fastest effort for 30-60 minutes which can represent; your effort, metabolic fitness, economy and anaerobic (above LT) endurance changes. This may work well for endurance events that last fewer than a couple of hours, however if your event requires longer efforts (i.e., marathons) the anaerobic component to the TT may not reflect how well you can actually sustain the sub-threshold paces involved in the longer races or efforts. Similarly, if you evaluate your TE by your races only you can't be sure if the slower than goal pace was due to poor pacing, weather, fueling, effort, dehydration, overtraining or low fitness.
Although lab testing is your best bet to evaluate your TE the feasibility of regular testing every month is low due to limiters like cost and logistics. Another option that can be included along with periodic lab testing is to evaluate sustainable pace by using a field test that can monitor your pace changes at a constant subthreshold heart rate. One way to do this is to choose a heart rate that is about 10 beats below your lactate threshold heart rate and then run a 1 mile time trial at that heart rate. If the mile time decreases at the targeted HR from test to test than your sustainable pace is improving. This is a relatively safe test as well as a great field test to determine your TE for races or events that take longer than 2-3 hours.
To start tracking your Sustainable Pace check out this tool: Sustainable Pace Tracker.
Sunday, February 13, 2011
Metabolic Efficiency
Metabolic efficiency can generally be defined as your ability to sustain more work (power, pace, etc.) while using less energy. More specifically ME can be defined as your body's ability to utilize more fat as fuel while sparing your limited amount carbohydrates.
To become more “metabolically efficient” will help you to access more of the 80,000 plus calories you have stored as fat and preserve the less than 2,000 calories available as stored carbohydrates.
To become more “metabolically efficient” will help you to access more of the 80,000 plus calories you have stored as fat and preserve the less than 2,000 calories available as stored carbohydrates.
Key Points: Training
Key point 1: Low to moderate intensity workouts are a key training component to improving your metabolic efficiency
Long duration and/or more frequent steady state workouts that are at or near the intensity of your Maxfat burn zone, which is about 55-65% of your MaxVO2, will help to optimize your ability to use fat as a fuel and help spare your limited but precious glycogen (i.e., stored carbohydrates).
Estimates are that even while exercising at your max fat burn zone your carbohydrate stores can sustain your effort for only around 5.5 hours before it will become necessary for you to slow down due to depletion problems. Additionally, pushing at intensities that are above that zone can severely shorten that duration potential. Obviously, this information is critically important for long course endurance athletes like Ironman and other ultra-distance athletes, but this concept may also be relevant in helping all athletes and exercisers to burn more fat while training. And this may be critical to recovery and in maximizing your power to weight ratio.
(Note: elite endurance athletes can often burn up to 8 calories per minute at their FatMax while most everyone else will burn less than half that amount).
The renewed focus on the importance of increasing fat utilization (i.e., metabolic efficiency) has been promoted by recent presentations by Registered Dietitian and Exercise Physiologist Bob Seebohar who believes you can “teach your body to burn more fat” and at the same time avoid gastrointestinal (GI) problems that are common with endurance athletes. He has observed that many athletes are not only limiting their potential to use more fat as energy but can actually be lowering their fat use because they are training too hard and consuming too many carbohydrates. This is especially relevant during the lower volume transition and base periods in training programs.
Read Bob Seebohar
http://www.usatriathlon.org/resources/multisport-zone/fuel-station/metabolic-efficiency-training
Sample metabolic efficiency training journey
http://www.usatriathlon.org/resources/multisport-zone/fuel-station/my-metabolic-efficiency-journey
Key Point 2: Increased training volume is the Key to maximizing fat utilization, increasing performance and burning body fat
Another key factor in optimizing endurance performance is your ability to maximize your volume of training by ramping up the frequency, duration and intensity of your training at a rate that you can continue to cope and recover. As long as you are able to adapt to performing more frequent, longer, and more intense workouts you will continue to increase your ability to maximize fat utilization, push up your sustainable pace, and give you an even greater net calorie expenditure. Of course the critical consideration when ramping up your volume is RECOVERY. Generally it takes many phases and even years to lift your training volume up to your potential safely.
Read: Matt Fitzgerald’s Racing Weight
http://www.velopress.com/sample/sample_RW.pdf
How does nutrition fit in the metabolic efficiency equation?
Key Point 3: Nutrition
Seebahor also recommends a periodized approach to eating which includes limiting your carbohydrates especially during your transition and base training periods. During these periods the focus should be on eating fruits, vegetables, lean protein and healthy fats and limiting sugars and grains. Your food intake should adjust according to the volume of your training with carbohydrates only increasing in concentration as training intensity and volume increases.
Read: Paleo Diet for Athletes by Joe Friel and Dr. Loren Cordain
http://www.thepaleodiet.com/paleo_books/forathletes.shtml or Bob Seebahor’s Nutrition Periodization for Athletes
http://www.amazon.com/Nutrition-Periodization-Endurance-Athletes-Traditional/dp/0923521836
In summary:Maximizing your endurance training effects will require walking a delicate line between pushing too hard too frequently which can limit your ability to use fat as a fuel, leading to early plateaus in your endurance fitness. On the other hand the volume in your training will need to be progressed with an appropriate dose of intensity to continue to maximize both fat utilization and sustainable power. Nutrition can play a critical role in helping you adapt to the training cycles necessary to reach your peak fitness. A periodized approach both to your training volume and your fuel intake is critical to your success.
Strategies:• During your base training periods start eating mostly fruits, vegetables, lean protein and healthy fats. Consider a periodized nutrition plan.Key point 1: Low to moderate intensity workouts are a key training component to improving your metabolic efficiency
Long duration and/or more frequent steady state workouts that are at or near the intensity of your Maxfat burn zone, which is about 55-65% of your MaxVO2, will help to optimize your ability to use fat as a fuel and help spare your limited but precious glycogen (i.e., stored carbohydrates).
Estimates are that even while exercising at your max fat burn zone your carbohydrate stores can sustain your effort for only around 5.5 hours before it will become necessary for you to slow down due to depletion problems. Additionally, pushing at intensities that are above that zone can severely shorten that duration potential. Obviously, this information is critically important for long course endurance athletes like Ironman and other ultra-distance athletes, but this concept may also be relevant in helping all athletes and exercisers to burn more fat while training. And this may be critical to recovery and in maximizing your power to weight ratio.
(Note: elite endurance athletes can often burn up to 8 calories per minute at their FatMax while most everyone else will burn less than half that amount).
The renewed focus on the importance of increasing fat utilization (i.e., metabolic efficiency) has been promoted by recent presentations by Registered Dietitian and Exercise Physiologist Bob Seebohar who believes you can “teach your body to burn more fat” and at the same time avoid gastrointestinal (GI) problems that are common with endurance athletes. He has observed that many athletes are not only limiting their potential to use more fat as energy but can actually be lowering their fat use because they are training too hard and consuming too many carbohydrates. This is especially relevant during the lower volume transition and base periods in training programs.
Read Bob Seebohar
http://www.usatriathlon.org/resources/multisport-zone/fuel-station/metabolic-efficiency-training
Sample metabolic efficiency training journey
http://www.usatriathlon.org/resources/multisport-zone/fuel-station/my-metabolic-efficiency-journey
Key Point 2: Increased training volume is the Key to maximizing fat utilization, increasing performance and burning body fat
Another key factor in optimizing endurance performance is your ability to maximize your volume of training by ramping up the frequency, duration and intensity of your training at a rate that you can continue to cope and recover. As long as you are able to adapt to performing more frequent, longer, and more intense workouts you will continue to increase your ability to maximize fat utilization, push up your sustainable pace, and give you an even greater net calorie expenditure. Of course the critical consideration when ramping up your volume is RECOVERY. Generally it takes many phases and even years to lift your training volume up to your potential safely.
Read: Matt Fitzgerald’s Racing Weight
http://www.velopress.com/sample/sample_RW.pdf
How does nutrition fit in the metabolic efficiency equation?
Key Point 3: Nutrition
Seebahor also recommends a periodized approach to eating which includes limiting your carbohydrates especially during your transition and base training periods. During these periods the focus should be on eating fruits, vegetables, lean protein and healthy fats and limiting sugars and grains. Your food intake should adjust according to the volume of your training with carbohydrates only increasing in concentration as training intensity and volume increases.
Read: Paleo Diet for Athletes by Joe Friel and Dr. Loren Cordain
http://www.thepaleodiet.com/paleo_books/forathletes.shtml or Bob Seebahor’s Nutrition Periodization for Athletes
http://www.amazon.com/Nutrition-Periodization-Endurance-Athletes-Traditional/dp/0923521836
In summary:Maximizing your endurance training effects will require walking a delicate line between pushing too hard too frequently which can limit your ability to use fat as a fuel, leading to early plateaus in your endurance fitness. On the other hand the volume in your training will need to be progressed with an appropriate dose of intensity to continue to maximize both fat utilization and sustainable power. Nutrition can play a critical role in helping you adapt to the training cycles necessary to reach your peak fitness. A periodized approach both to your training volume and your fuel intake is critical to your success.
• Start Tracking all your exercise and food intake on http://www.trainingpeaks.com/
• Consider tracking your power to weight ratio and metabolic efficiency at a credible human performance testing lab.
o Test your metabolic efficiency on the treadmill, bike or both to evaluate your current ability to burn fat and to determine your max fat burn zone.
o Re-test your metabolic efficiency if the baseline test determined that your fat utilization was limited.
o Test your body composition to evaluate body fat% and lean mass changes.
o The goal with this testing is to set your training parameters (i.e., what pace and heart rate is associated with my max fat level) and to determine if your training and nutrition changes are having the desired effect.
Seebohar refers to the crossover point as the"Metabolic Efficiency Point" which is the intensity where carbohydrates first begin to burn at a greater rate than your fat energy. The goal is to move this point to the right on the graph below so that the Metabolic Efficiency Point will occur at higher pace or power outputs. To determine your individual crossover you’ll need to get tested.
If you have an interest in optimizing your metabolic efficiency the Fit Stop is currently offering an opportunity for you to experiment with some of these concepts by participating in our Metabolic Exercise Profile. This testing will provide the following useful information and tools to help you maximize your endurance potential and a greater ability to decrease your body fat:
• An Exercise Metabolic Assessment to determine your current Maxfat level, aerobic threshold, and cross-over point (where you begin to burn more carbohydrates than fat).
• Determine your metabolic training zones for heart rate, power and pace.
• Receive your own energy expenditure table which will list your calories expenditure rate for carbs and fat at various sub-maximal intensity levels. See sample table at www.fitstop-lab.com/tools/metabolicefficiency.xls
• An exercise physiologist will also help you set-up your training program and tracking system using the Training Peaks platform.
• Re-evaluations will be included at half price.
Contact us at kjnico@fitstop-lab.com or call 760-634-5169
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