Keep in mind when evaluating the study below that "quicker" fitness does not necessarily mean optimal. Your goal will dictate the specificity of your training. If you are looking to run a marathon then interval training is only one small (all be it important) componant to your training plan. Or if you are focussed on "Finshing Strong" - then getting fit "quickly" is not as critical. "Quickly" can also suggest to me a greater potential for overuse injury. Be smart and have fun!
Interval Training Burns More Fat, Increases Fitness, Study Finds
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Friday, July 31, 2009
Thursday, July 30, 2009
Lactate Threshold (what's the big deal?)
Research says...
Lactate is produced as a side reaction in a metabolic process called glycolosis. Glycolosis is the body's energy system that breaks down carbohydrates (glucose) that are stored in muscle and liver to produce energy. Lactate IS NOT the cause of acidosis - that burning sensation your feel in the muscle - but rather it is the byproduct of glucose breakdown during intense exercise. So lactate is actually an indirect measure of acidosis or muscle fatigue.(1)
Your Lactate Threshold (LT) is a marker showing how much exercise (or physical work) you can sustain before the evidences of glycolosis are present. More specifically LT is that point in your exercise level where you begin to accumulate lactate in the blood and breathing becomes noticeably more labored (ventilatory changes). LT usually corresponds to your best 15k or 10 mile running pace or a 40k time trial on a road bike.
Your LT can be evaluated by several methods that include monitoring your heart rate, oxygen consumption and Power output or speed at LT. With appropriate training technique you can increase your LT which will enhance your body's ability to increase energy production through mitochondrial respirations ( or more aerobic pathways) thus decreasing the reliance on energy from glycolosis (anaerobic). Which means you can spare your glycogen (ie., your stored carbohydrates) which are in limited supply compared to the large amount of energy you have available from fat storage.
Additionally, smart endurance training will improve your acidosis-buffering effect, thereby decreasing fatigue allowing for a longer tolerance of challenging workouts and an enhanced training effect allowing for even more intense training. Here are some the recommendations from the literature on how to improve your LT:
An intense workout that is slightly above the LT is considered by some researchers to be the best for boosting LT (2)
20 minutes or more of training at a HR just above the LT is enough to significantly increase LT (3)
LT tends to be higher in older runners with one study showing the average LT at 85% of MaxVO2 for older runners and 79% for younger. Keep in mind that MaxVO2 scores are lower in the older athletes since they tend to decline with age. (4)
Research suggests that training programs that are a combination of high volume, interval and steady-state workouts have the most pronounced effect on lactate threshold improvement. (5)
Further applications:
Knowing your heart rate at LT allows the heart rates of other training zones to be calculated. For example, base endurance training (the longer slower training in zone 2) is typically 90-95% of your LT heart rate and the harder LT interval training in zone 4 is about 105% of LT while tempo training workouts are usually right around LT. The prescription of training using individual heart rate zones based on the LT heart rate (from exercise testing) can have a profoundly beneficial effect on training adaptation.
Retesting: If training goes well and the HR prescription proves to be ideal for moving the threshold higher (to the right) then the program is working. If however, the results are not as effective as planned then modifications in the training plan would be warranted.
Lactate is produced as a side reaction in a metabolic process called glycolosis. Glycolosis is the body's energy system that breaks down carbohydrates (glucose) that are stored in muscle and liver to produce energy. Lactate IS NOT the cause of acidosis - that burning sensation your feel in the muscle - but rather it is the byproduct of glucose breakdown during intense exercise. So lactate is actually an indirect measure of acidosis or muscle fatigue.(1)
Your Lactate Threshold (LT) is a marker showing how much exercise (or physical work) you can sustain before the evidences of glycolosis are present. More specifically LT is that point in your exercise level where you begin to accumulate lactate in the blood and breathing becomes noticeably more labored (ventilatory changes). LT usually corresponds to your best 15k or 10 mile running pace or a 40k time trial on a road bike.
Your LT can be evaluated by several methods that include monitoring your heart rate, oxygen consumption and Power output or speed at LT. With appropriate training technique you can increase your LT which will enhance your body's ability to increase energy production through mitochondrial respirations ( or more aerobic pathways) thus decreasing the reliance on energy from glycolosis (anaerobic). Which means you can spare your glycogen (ie., your stored carbohydrates) which are in limited supply compared to the large amount of energy you have available from fat storage.
Additionally, smart endurance training will improve your acidosis-buffering effect, thereby decreasing fatigue allowing for a longer tolerance of challenging workouts and an enhanced training effect allowing for even more intense training. Here are some the recommendations from the literature on how to improve your LT:
An intense workout that is slightly above the LT is considered by some researchers to be the best for boosting LT (2)
20 minutes or more of training at a HR just above the LT is enough to significantly increase LT (3)
LT tends to be higher in older runners with one study showing the average LT at 85% of MaxVO2 for older runners and 79% for younger. Keep in mind that MaxVO2 scores are lower in the older athletes since they tend to decline with age. (4)
Research suggests that training programs that are a combination of high volume, interval and steady-state workouts have the most pronounced effect on lactate threshold improvement. (5)
Further applications:
Knowing your heart rate at LT allows the heart rates of other training zones to be calculated. For example, base endurance training (the longer slower training in zone 2) is typically 90-95% of your LT heart rate and the harder LT interval training in zone 4 is about 105% of LT while tempo training workouts are usually right around LT. The prescription of training using individual heart rate zones based on the LT heart rate (from exercise testing) can have a profoundly beneficial effect on training adaptation.
Retesting: If training goes well and the HR prescription proves to be ideal for moving the threshold higher (to the right) then the program is working. If however, the results are not as effective as planned then modifications in the training plan would be warranted.
You can get tested to determine your LT at the Fit Stop Human Performance Lab in Carlsbad, CA. go to http://www.fitstop-lab.com/fitnesstesting.htm
1. Robergs, R.A. Ghiasvand, F., & Parker, D. 2004. Biochemistry of exercise-induced metabolic acidosis. American Journal of Physiology - Regulatory, Integrative and Comparative Physiology, 287, R502-16.
2. Increased Training Intensity Effect on Plasma Lactate, Ventilatory Threshold, and Endurance.". Medicine an Science in Sports and Exercise, Vol 21 (5), pp 563-568, 1989.
3. Changes in Onset of Blood Lactate Accumulation (OBLA) and Muscle Enzymes after Training at OBLA, European Journal of Applied Physiology, Vol 49, pp 45-57, 1982
4. Lactate Threshold and Distance Running Performance in Young and Older Endurance Athletes," Journal of Applied Physiology, Vol 58(4) pp 1281-1284, 1985
5. Robergs, R.A. , & Roberts, S. 1997. Exercise Physiology: Exercise , Performance, and Clinical Applications, St. Louis, MO: Mosby
The information and programs are for informational purposes only. They do not substitute for the advice of a qualified health care professional or physician.
1. Robergs, R.A. Ghiasvand, F., & Parker, D. 2004. Biochemistry of exercise-induced metabolic acidosis. American Journal of Physiology - Regulatory, Integrative and Comparative Physiology, 287, R502-16.
2. Increased Training Intensity Effect on Plasma Lactate, Ventilatory Threshold, and Endurance.". Medicine an Science in Sports and Exercise, Vol 21 (5), pp 563-568, 1989.
3. Changes in Onset of Blood Lactate Accumulation (OBLA) and Muscle Enzymes after Training at OBLA, European Journal of Applied Physiology, Vol 49, pp 45-57, 1982
4. Lactate Threshold and Distance Running Performance in Young and Older Endurance Athletes," Journal of Applied Physiology, Vol 58(4) pp 1281-1284, 1985
5. Robergs, R.A. , & Roberts, S. 1997. Exercise Physiology: Exercise , Performance, and Clinical Applications, St. Louis, MO: Mosby
The information and programs are for informational purposes only. They do not substitute for the advice of a qualified health care professional or physician.
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