Lactate Response of Elite Road Cyclists.

1. Lactate Response of Elite Road Cyclists.

2. Background. • What is being tested? – Lactate response to exercise within an elite road cyclist. • Why is it relevant? – It can be determined through submaximal testing and has been suggested to be a better marker of endurance performance than VO2 max • What can the test offer? – Indicator of training adaptation, correlate with endurance performance and indicate optimal training stimuli. • Blood Lactate Accumulation. (Physiology, Buffering). • Terminology & Definitions (Lactate Threshold and Onset of Blood Lactate Accumulation). • More Specific terminology associated with higher validity and reliability.

3. Underlying Theory. • Lack of oxygen is not necessarily responsible for an increase in lactate production or even lactate accumulation. Other causative factors may play a more significant role. • Blood lactate accumulation represents only the balance of production and removal. It says nothing about the absolute values of either of these. • Only relatively short, very intense activity causes lactic acid to accumulate. Lactic acid is not thought to be a contributor to fatigue in low-moderate intensity activity of any duration. • Lactate is an important substrate that can be used during sub maximal exercise, recovery and at rest. It is the preferred source of fuel for the heart and brain. • Lactic acid or lactate ‘pooling’ is not the cause of delayed muscle soreness. • Lactate accumulation and not necessarily an increase in production, causes an increase concentration of hydrogen ions and corresponding acidosis. Lactate production may actually help to curb the development of acidosis. • Acidosis is thought to be a primary factor in muscular fatigue and is based on a good deal of research. Recent research is contesting this claim but it is still too early to dismiss acidity as a cause of fatigue. • Training accelerates lactate clearance, reduces lactate accumulation at any given workload and results in a greater level of lactate accumulation during maximal effort. • This is clearly an area that is far from resolved but what seems clear is that lactate can no longer be labelled definitively as the athlete’s enemy. On the contrary, gathering evidence suggests that many aspects of lactate production are beneficial to athletic performance. (McArdle et al, 2006; Weltman 1995)

4. Relevant Tests. • Protocol related factors must have considerations :- • Predictive assessments won’t be considered due to error (MHR, HRR and VO2 max). The Conconi test (Conconi et al. 1982) has been shown to have a significant degree of measurement error, contrasting data shows Ratings of Perceived Exertion may be of a better relation, even though cause and effect cannot be established. Direct measurement is the preferred. • Lab vs. Field. • Invasive and non-invasive (Lactate Analyzer). • Ergometer type. • Continuous vs. Discontinuous. • Arterial vs. Venous sampling site. • Do not disregard factors such as – muscle fibre type, substrate availability, caffeine usage and training state. Altitude and ambient temperature can also affect the response. (Weltman, 1995)

5. Relevant Tests. • Field Based – (30-Minute Time Trial). • Assuming maximal, well-paced effort can elicit reliable and accurately reflected time trial specific fitness. Power and H.R., will gauge L.T. paired with Blood Lactate Analysis. • However limitations can occur through – (e.g. - calibration of equipment and bicycle) (Jeukendrup et al. 1996; Coyle et al. 1991) • Lab Based – (Graded Exercise Test). • Transitions can correlate well with individual time-trial performance. (“A 10% improvement in anaerobic threshold would decrease 26km individual time trial by approximately 4%) • Testing procedures must be applied stringently. (Coyle et al. 1988, Craig et al. 1993)

6. My Chosen Test. • Lab test – for gauging level of thresholds. • Testing equipment – Athletes preference. • SRM Type Ergometer, fully calibrated with adapted cycle pedals, flywheel and gears. (Hyperbolic setting) • Gas collection & gas analysis equipment. Heart rate and ECG recording • Continuous type. (For acquisition of steady state.) • Assessment through, Lactate Pro Portable Analyzer with analysis equipment. • Fingertip sampled at intervals. (McNaughton et al. 2002)

7. Causes for Concern. • Factors that are of concern for an exercise physiologist; • Work duration. • Calculation methods. • Technique associated with blood collection. • Handling and analysis. • Ergometer type. • Ambient environment. • Pre-test exercise and diet. (Gore, 2000)

8. Conclusion. • Lactate Debate – Is there any actual threshold or is it a point of reference that is constantly changing and it doesn’t exist at all? Any delay in the onset of blood lactate accumulation can be seen as beneficial to the athlete in question. • In researching the various tests, it would be more appropriate for an Elite cyclist to test lactate response by using a laboratory based ergometer cycle due to the controlled, and stable environment. However, it must be supplemented with a Field test for further development. • The mass of information that can be gained, and the greater accuracy in the control of workloads. • Also research has shown non significant differences between lab vs. field data acquisition (Brettoni et al., 1989; Foster et al., 1993) • Although much is known about the blood lactate response to exercise, there are many unanswered questions. At present it is known that the response is a good method for predicting endurance performance and a useful technique for monitoring the effects of training. In the future, information should be forthcoming regarding optimal training techniques for improving the blood lactate response to exercise and, in turn, for improving athletic performance.

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