Relationship Between Lactate Threshold, Obla, Vo2 Max and 5k Running Performance

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Relationship Between Lactate Threshold, OBLA, VO2 Max And 5k Running Performance

Abstract
Research into the relationship between physiological variables and running performance has been variable. The aim of this study was to examine the relationship between 5k running performance and a number of physiological variables in a group of 11 trained club runners (Age 21.451.63yrs, Height 175.092.77cm, Weight 67.865.12kg). The athletes underwent a laboratory treadmill test to determine their maximum oxygen uptake (VO2 max) and running velocities at lactate threshold (v-Tlac) and blood lactate concentration of 4mM (v-OBLA). Running performance was determined by a 5k time-trial on an athletics track for which the average time was 1097.09 ± 108.02 secs. The mean velocities for v-Tlac and v-OBLA were 15.18 ± 1.5km/h, 16.76 ± 1.60 km/h and mean VO2max was 59.10 ± 3.54 ml/kg/min. The best single predictors of 5k running performance were v-OBLA and VO2max (p = .003, p = .007) while v-Tlac was slightly poorer (p = .013). It is concluded that lactate variables may be valid and reproducible predictors for 5km running performance.

Introduction
Research throughout history has established that a number of physiological variables relate to distance running performance, including Lactate Threshold (Tlac), OBLA and VO2 Max (Conley and Krahenbuhl, 1980; Costill, Thomason and Roberts, 1973; Coyle et al, 1983; Farrell et al, 1979; Hagberg and Coyle, 1983; Lafontaine, Londeree and Spath, 1982). The results from this research have been variable. Evidence has shown that blood lactate variables highly correlate with running performance over a variety of distances. Additionally, these variables contribute to running performance variance more than any other physiological variables (Yoshida et al, 1990, 1993). ‘Lactate Threshold’ describes the point at which exercise begins to hurt more than it should because the body’s lactate production exceeds the body's ability to flush it away (Robergs & Roberts, 1997). It is the exercise intensity at which lactate threshold occurs that can be used as a significant predictor of endurance performance (Allen et al, 1985; Coyle et al, 1988; Farrell et al, 1979). It is considered a powerful tool for developing effective training regimes and as a method of monitoring adaptation to endurance performance, although to be effective at fulfilling these roles, the measurement of lactate threshold must be reliable. OBLA is the Onset of Blood Lactate Accumulation. OBLA is accepted as an incremental method for detecting the lactate deflection point (Australian Sports Commission, 2000). Being able to detect this point is crucial as it is an indication of when an athlete switches from a predominantly aerobic to anaerobic metabolism, which leads to hastened fatigue. It is established that a level of ~ 2 - 4 millimoles per dm3 (litre) represents OBLA. Duggan and Tebbutt (1990) examined blood lactate concentrations of non-athletes during a treadmill protocol at 12 km/h. Results suggested vOBLA to be a reproducible performance predictor. In addition to Lactate variables, sports scientists measure VO2 max to objectively evaluate a subject’s functional aerobic capacity. VO2 max is the maximum volume of oxygen that can be utilised in one minute during maximal or exhaustive exercise (Bassett & Howley 2000). The majority of research using heterogeneous groups has found that VO2 Max correlates highly with running performance (Costill et al, 1973; Thomason and Roberts, 1973; Foster et al, 1978). However, when moderately homogeneous groups were tested, low-moderate correlations were found (Conley and Krahenbuhl, 1980; Morgan et al, 1989). Saltin and Astrand (1967) discovered that high VO2 Max values in subjects have been related to successful running performance, because traditionally the oxygen cost of running is directly proportional to running speed. Grant et al (1997)...
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