Lactate accumulates in the blood as a response to an increase in speed or intensity that the athlete is working at. During incremental exercise there has been two lactate thresholds identified when plotting blood lactate accumulation against exercise intensity. The lactate threshold is identified as the first sudden and sustained increase in blood lactate accumulation above resting values. This normally occurs between 1-2 mM of blood lactate concentration. There exists a balance here between lactate production and removal, therefore performance can continue without the onset of fatigue. This marker indicates an intensity transition from a moderate exercise zone into a heavy zone. As intensity or speed increases there is a distinct second sudden and sustained increase in blood lactate accumulation which occurs at approximately 2.5-4.0 mM of blood lactate accumulation. This is known as the lactate turn-point. At this intensity lactate production far outweighs the ability of the muscle to remove it, therefore no steady state is achievable. The intensity at which the lactate turn-point occurs is of importance to endurance athletes as it is an accurate indication of successful aerobic endurance performance. The maximum aerobic speed indicates the maximum speed attainable before fatigue terminates performance.
An incremental intensity exercise test is used to determine lactate threshold, lactate turn-point and maximum aerobic speed values. Following a five minute warm up on the treadmill, the subject begins the test at 8km/h. The speed increases every two minutes by 0.5km/h until the subject reaches exhaustion. Heart rate and a blood sample to measure lactate accumulation are taken in the final minute of each stage. Resting values of blood lactate and heart rate are taken prior to test initiation.
Athlete One
Fig 1. Graph to show results from athlete one incremental treadmill test.
The lactate threshold (LT) of athlete one occurs at approximately 1.1mM of blood lactate concentration and at a speed of 10.5km/h, which also indicates the transition from a moderate intensity to heavy. The heart rate that corresponds to the lactate threshold is 103b/min. The lactate turn-point (LTP) occurs at 3.5mM of blood lactate and at an intensity of 14.5km/h. The corresponding heart rate at this intensity is 145b/min. This also indicates the transition from a heavy intensity to very heavy. The maximum aerobic speed of athlete one is 17.5km/h with a maximum lactate value of 8mM and maximum heart rate of 191b/min. Intensities above these values indicate the severe intensity training zone.
Athlete One Recomended Training Zones
Athlete Two
Fig 2. Graph showing results from athlete two incremental treadmill testing.
The lactate threshold (LT) of athlete two occurs at approximately 1.3mM of blood lactate concentration and at a speed of 10.5km/h, which also indicates the transition from a moderate intensity to heavy. The heart rate that corresponds to the lactate threshold is 89b/min. The lactate turn-point (LTP) occurs at 3.6mM of blood lactate and at an intensity of 15.0km/h. The corresponding heart rate at this intensity is 134b/min. This also indicates the transition from a heavy intensity to very heavy. The maximum aerobic speed of athlete one is 19.5km/h with a maximum lactate value of 8.6mM and maximum heart rate of 185b/min. Intensities above these values indicate the severe intensity training zone.
Athlete Two Recomended Training Zones
Athlete Three
Fig 2. Graph showing results from athlete three incremental treadmill testing.
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The lactate threshold (LT) of athlete three occurs at approximately 1.0mM of blood lactate concentration and at a speed of 10.5km/h, which also indicates the transition from moderate intensity to heavy. The heart rate that corresponds to the lactate threshold is 91b/min. The lactate turn-point (LTP) occurs at 2.5mM of blood lactate and at an intensity of 13.5km/h. The corresponding heart rate at this intensity is 134b/min. This also indicates the transition from a heavy intensity to very heavy. The maximum aerobic speed of athlete one is 19.0km/h with a maximum lactate value of 8.0mM and maximum heart rate of 193b/min. Intensities above these values indicate the severe intensity training zone.
Athlete Three Recomended Training Zones
The athlete that can perform at the highest speed without accumulating large amounts of blood lactate will demonstrate an increased level of performance due to an increase in running economy. This is due to the athlete being able to expend less energy to maintain a given intensity or running speed. Establishing training zones allows the individual prescription of exercise intensities to be achieved. This in turn allows the athlete to structure a condition program to increase the intensity at which lactate begins to accumulate in the blood. After completing this testing, training intensities can accurately be achieved with the aid of heart rate monitors or GPS devices to cross reference blood lactate values with respected speeds or heart rate.
Training within the moderate intensity zone will consist of continuous, very low intensity, long slow distance running with a duration of 40-120 minutes. It is similar to the warm-up/cool down intensity that athletes perform before and after activity. Training at the intensity of the lactate threshold will allow the athlete to become more efficient at clearing lactate and adaptation will result in a higher speed attainable at LT, with lower lactate accumulation. Training in this zone will also increase the utilization of fat as the main energy source, preserving glycogen stores for when increased intensity is required. Training above the lactate threshold in the heavy zone would consist of long and short interval training. This also improves the muscles ability to clear lactate and will increase muscle blood flow to allow higher oxygen utilization. Sessions in this zone will consist of working at an intensity that can be maintained at a steady tempo for approximately 30-60 minutes. In the very heavy training zone interval training is best suited. This would involve 3-5 minute work intervals, separated by the same amount of rest. A work to rest ratio of 1:1. This will allow the athlete to train at close to the maximum aerobic speed for a greater amount time than would be possible at a single continuous pace. The severe training zone would consist of sprint intervals lasting 10-60 seconds with much larger rest periods of 2-5 minutes to allow for full recovery. The idea of this training is to familiarize the body with large accumulations of blood lactate, which will be a result of the extremely high work intensity.
A correctly periodized program would incorporate all intensity zones at some stage, using a variation between heavy and light training days to maximize physical adaptation and allow for adequate recovery between hard sessions.
References
1. Bompa, T. & Buzzichelli, C. (2015). Periodization Training for Sports – 3rd edition. United States: Human Kinetics
2. Eston, R. & Roger, E. (2008) Kinanthropometry and Exercise Physiology Laboratory Manual: Tests, Procedures and Data – 3rd edition: Volume 2: Physiology. Edited by Thomas Reilly . New York: Taylor & Francis
3. Strength, N., Asscociation, C., Baechle, T.R. & Earle, R.W (2008) Essentials of Strength and Conditioning – 3rd edition. Champaign, IL: Human Kinetics ![endif]--
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