Wednesday, June 18, 2008

LT (Lactate Threshold) and RE ( Running Economy)!

Recently, attended the Training for Higher Performance Seminar by Coach Guy Oden, found the talk very Enlightening . He confirms that i must strengthen my Core Muscles to enhance my Running Economy in order to sustain faster pace ( without succumbing to injuries)It is the necessary Evil to raise LT in order to improve my marathon timings which seem to be stuck in 3hr 50min ranges!!!
Here is DKW's Summary of the Coach Guy's Talk.

How..2-Lessons_Runner i Found this article from Running Times Useful!!! Here is the Extracts....

Physiology lesson 1.0

Lactate threshold and running economy are more important than VO2 max. What It Means For You: Threshold training (tempo runs), high mileage, and power workouts are more important than long intervals, especially once your VO2 max has plateaued.

While VO2 max (the maximum volume of oxygen your muscles can consume per minute) has received most of the attention among runners and coaches, a high VO2 max alone is not enough to attain elite-level performances; it simply gains one access into the club, since a runner cannot attain a high level of performance without a high VO2 max. But, while you can improve your VO2 max, it is largely genetically determined. The other two major physiological players of distance running performance -- lactate threshold (LT) and running economy (RE) -- exert a greater influence on your performance and are more responsive to training. I have tested many athletes with an elite-level VO2 max in the laboratory but few of them were capable of running at the elite or even sub-elite level because they did not have a high LT or were not very economical.

From the time of the classic study published in Medicine and Science in Sports and Exercise in 1979 by some of the most prominent names in exercise physiology (Farrell, Wilmore, Coyle, Billing, and Costill), research has shown that the LT is the best physiological predictor of distance running performance. This threshold demarcates the transition between running that is almost purely aerobic and running that includes significant oxygen-independent (anaerobic) metabolism. It represents the fastest speed you can sustain aerobically. (All running speeds have an anaerobic component, although at speeds slower than the LT, that contribution is negligible.) Since the LT represents your fastest sustainable pace, the longer the race, the more important your LT.

Running Economy (RE) is the v
olume of oxygen consumed at submaximal speeds. In 1930, David Dill and his colleagues were among the first physiologists to suggest that there are marked differences in the amount of oxygen different athletes use when running at the same speeds, and that these differences in "economy" of oxygen use are a major factor explaining differences in running performance of athletes with similar VO2 max values. For example, research has shown that, while Kenyan runners have VO2 max and LT values similar to their American/European counterparts, the Kenyans are more economical, possibly due to their light, non-muscular legs that interestingly resemble those of thoroughbred race horses. The heavier your legs, the more oxygen it takes to move them.

RE is probably even more important than the LT in determining distance running performance because it indicates how hard you're working in relation to your maximum ability to use oxygen. For example, if two runners have a VO2 max of 70 milliliters of oxygen per kilogram of body weight per minute and an LT pace of 7 minutes per mile, but Jack uses 50 and Martin uses 60 milliliters of oxygen while running at 7:30 pace, the pace feels easier for Jack because he is more economical. Therefore, Jack can run faster before using the same amount of oxygen and feeling the same amount of fatigue as Martin. I have yet to see a runner who has superior RE who does not also have a high VO2 max and LT.

1.1 Raise Your Threshold

Sample workouts to raise your lactate threshold (LT):

1. Continuous runs at LT pace, starting at about 3 miles and increasing up to 7 to 8 miles (or about 45 min.) for marathoners.

2. Intervals @ LT pace with short rest periods, such as 4 to 6 x 1 mile @ LT pace with 1 min. rest.

3. Shorter intervals at slightly faster than LT pace with very short rest periods, such as 2 sets of 4 x 1,000 meters @ 5 to 10 seconds per mile faster than LT pace with 45 seconds rest and two min. rest between sets.

4. Long, slow distance runs with segments run at LT pace (for marathoners), such as 12 to 16 miles with last 2 to 4 miles @ LT pace or 2 miles + 3 miles @ LT pace + 6 miles + 3 miles @ LT pace.

1.1a What's your LT Pace?

LT pace is about 10 to 15 seconds per mile slower than 5K race pace (or about 10K race pace) for slower runners (slower than about 40 minutes for 10K). If using a heart rate (HR) monitor, the pace is about 75 to 80 percent of maximum HR. For highly trained and elite runners, LT pace is about 25 to 30 seconds per mile slower than 5K race pace (or about 15 to 20 seconds per mile slower than 10K race pace) and corresponds to about 85 to 90 percent max HR. For many, it corresponds closely to the race pace they can sustain for one hour. The pace should feel "comfortably hard."

1.2 Improve your economy

Despite its importance, running economy (RE) seems to be the most difficult of the three physiological players (LT, VO2 max and RE) to train. While many runners and coaches think that RE is a reflection of running form, it is more influenced by those microscopic structures that influence oxygen delivery to and use by the muscles -- capillaries and mitochondria, the densities of which are both enhanced with high mileage. Research has shown that runners who run high mileage (more than 70 miles per week) tend to be more economical, which leads one to believe that running high mileage improves RE. In addition to increasing mitochondrial and capillary density, the greater repetition of running movements may result in better biomechanics and muscle fiber recruitment patterns and a synchronization of breathing and stride rate, which may reduce the oxygen cost of breathing. RE may also be improved by the weight loss that often accompanies high mileage, which lowers the oxygen cost. Since VO2 max plateaus with about 70 to 75 miles per week, improved RE may be the most significant attribute gained from running high mileage. However, it's hard to prove cause and effect, since it is not entirely clear whether high mileage runners become more economical by running more miles or are innately more economical and can therefore handle higher mileage.

Other forms of training, like intervals and tempo runs, can also improve RE since, as VO2 max and LT improve, the oxygen cost of any submaximal speed is also likely to improve. However, it is possible to become more economical without improving VO2 max or LT, as research on power training with very heavy weights and plyometrics has shown. Power training focuses on the neural, rather than the metabolic, component of muscle force development to improve RE.

1.3 Boost Your VO2 max

While LT and RE are more important than VO2 max, you don't want to ignore your VO2 max, which is important to reach your running potential and is largely dictated by your stroke volume (the amount of blood your heart pumps with each contraction of its left ventricle) and cardiac output (the amount of blood pumped by your heart each minute). Long intervals provide the heaviest load on the cardiovascular system because of the repeated attainment of the heart's maximum stroke volume and cardiac output (and, by definition, your VO2 max). In lieu of a laboratory test to tell you the velocity at which VO2 max is achieved (vVO2 max), you can use current race performances or heart rate. vVO2 max is close to 1-mile race pace for recreational runners and close to 2-mile race pace (10 to 15 seconds per mile faster than 5K race pace) for highly trained runners. You should be within a few beats of your maximum heart rate by the end of each interval.

Sample workouts to boost your VO2 max:
1. 3 x 1,200 meters (or 4-5 min.) @ vVO2 max with 3 to 4 min. recovery
2. 4 x 1,000 meters (or 3-4 min.) @ vVO2 max with 2 to 3 min. recovery
3. 6 x 800 meters (or 3 min.) @ vVO2 max with 2 to 3 min. recovery.

Physiology lesson 2.0

Runners with different muscle fibers have different strengths. What It Means For You: Tailor your training to match your muscle fiber composition.

There are two types of runners -- those who have superior speed, whose performance gets better as the race gets shorter, and those who have superior endurance, whose performance gets better as the race gets longer. Despite this, most runners, unless they are individually coached, follow some generic training program. However, those programs don't acknowledge differences in runners' muscle fiber types and their associated metabolic profiles. The types of fibers that make up individual muscles greatly influence your performance.

Humans have three different types of muscle fibers, with gradations between them (see Characteristics of the 3 Muscle Fiber Types). Slow-twitch (ST) fibers are recruited for all of your aerobic runs, while fast-twitch B (FT-B) fibers are only recruited for short anaerobic, high-force production activities, such as sprinting, hurdling, and jumping. Fast-twitch A (FT-A) fibers, which represent a transition between the two extremes of ST and FT-B fibers, are recruited for prolonged anaerobic activities with a relatively high-force output, such as racing 400 meters. It's a given that you have more ST fibers than FT fibers, otherwise you would be a sprinter rather than a distance runner. However, even within a group of distance runners, there is still a disparity in the amount of ST fibers. Some runners may have 90 percent ST and 10 percent FT fibers (marathoners), while others may have 60 percent ST and 40 percent FT fibers (milers).

Understanding your fiber type can help you train smarter. While most runners do the same workouts to focus on a specific race, your training and racing should reflect your physiology. For example, if you have 90 percent ST and 10 percent FT fibers, your best race will likely be the marathon and your training should focus on mileage and tempo runs. If you have 60 percent ST and 40 percent FT fibers, your best race will likely be the 800m or mile, and your training should focus less on mileage and more on interval training. If both runners want to race a 5K or 10K, the former runner should initially do longer intervals, trying to get faster with training, such as 1,200m repeats at 5K race pace, increasing the speed to 3K race pace or decreasing the recovery as training progresses. The latter runner should do shorter intervals, trying to hold the pace for longer with training, such as 800m repeats at 3K race pace, increasing the distance to 1,200 meters or increasing the number of repeats as training progresses. Thus, there can be two paths to meet at the same point.

2.1 What's Your (Muscle) Type?

In lieu of a muscle biopsy to determine your exact muscle fiber type composition, ask yourself the following questions:

1. When you race, a) are you able to hang with your competitors during the middle stages, but get out-kicked in the last quarter to half-mile, or b) do you have a hard time maintaining the pace during the middle stages, but can finish fast and out-kick others?

If you answered (a), you probably have more ST fibers. If you answered (b), you have more FT fibers.

2. Which type of workouts feel easier and more natural -- a) long intervals (800m to mile repeats), long runs, and tempo runs, or b) short, fast intervals (200s and 400s)?

If you answered (a), you have more ST fibers. If you answered (b), you have more FT fibers.

3. Which workouts do you look forward to more -- a) long intervals and tempo runs, or b) short, fast intervals?

If you answered (a), you have more ST fibers. If you answered (b), you have more FT fibers. (People tend to get excited about tasks at which they excel, while being more anxious about tasks that are difficult.)

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