The aim of this study was to determine a relationship between the athlete's speed during a 10 km time trial and the speed when the blood lactate concentration has reached 4mM causing muscle fatigue and inhibiting performance.

Introduction

Scientists believe that there are two important factors which influence endurance performance: VO²max and OBLA (onset of blood lactate accumulation). However, athletes do not perform endurance exercise at their VO2max. “The exercise intensity at the point of OBLA consistently and powerfully predicts endurance exercise performance of men and women” (McArdle et al. 2001)

A blood lactate threshold will determine the heart rate at which OBLA occurs in the athlete. By knowing the heart rate at which their blood lactate threshold occurs, the athlete may train at the intensity he/she requires for his/her workout (HASTC 2001).

If an athlete can delay OBLA from occurring, then it will allow them to exercise closer to their VO2 max. “The closer an athlete is able to sustain exercise performance to their VO2 max without reaching their blood lactate threshold, increase the possibility that they will perform better or more efficiently” (HASTC 2001).

There have been many studies to demonstrate that there is a correlation between the response of blood lactate concentration and various types of endurance exercise (Grant et al. 2001). However some of the studies have shown limitations. For example, “the studies by Weltman et al. (1990) used only male subjects, did not standardise diet or prior physical activity, and performed little statistical analysis” (Grant et al. 2001). Pfitzinger and Freedson (1998) did standardise diet and physical activity, however there were short comings in their statistical data.

In 1990 a reproducibility study (Weltman et al.) was conducted using paired students t-tests and correlation coefficients to compare results their tests. However, there is no random variation between tests and correlation coefficients are not systematically biased. Grant et al. (2001) also suggests, “The result can be influenced by the range of values in the sample”.

The purpose of this study was to investigate the relationships between an athlete’s speed (at the 4mM blood lactate concentration) during an incremental test and a 10 km time trial, also an attempt to determine a correlation between max heart rate and ...

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Discussion

The aim of this study was to determine a relationship between the athlete’s speed during a 10 km time trial and the speed when the blood lactate concentration has reached 4mM causing muscle fatigue and inhibiting performance. Also, to determine a relationship between HRmax prior to exhaustion and speed10km.

The results show that there is a strong relationship between speed 4mM and speed 10km (r= 0.94, p<0.05). The graph (figure 1) shows a positive correlation, because athletes that had a high average speed 10km also had a high speed 4mM, the same applies for the athletes who had a low average speed10km had a corresponding low speed 4mM.

Figure 2 shows scattered data exhibiting the fact there is no relationship between HRmax and speed10km as there is no correlation whatsoever. The data is random and shows that the faster athletes reaching speed10km of 17.3 km.h -1 had lower HRmax than that of the slowest athletes, Speed10km 14.1 km.h -1.

An endurance athlete’s performance depends on how fast they can run before reaching a blood concentration level of 4mM. For example, the data shows that an athlete who hits his/her 4mM blood lactate concentration at 13 km.h-1 is not going to perform as well as an athlete who has a threshold of 16 km.h-1 running comfortably at a speed of 15 km.h-1.

This is shown in the data by the positive relationship displayed in the graph (figure 1).

The results demonstrate the importance of regularly undertaking blood lactate tests for endurance athletes. The investigation has shown that each individual has their own barrier to exercise and that OBLA occurs at different levels of exercise depending on the individual. Knowing the HRmax at which OBLA occurs allows them to train closer to their VO2max producing a more efficient performance.

Relationship between performance and physiological laboratory data

Abstract

The aim of this study is to investigate speed at 4mM and maximum heart rate: relationship with 10 km running performance. A group of fifteen trained runners (7

male and 8 female) were selected to participate in to experiments.

The first was an incremental test to exhaustion. The treadmill was kept at a gradient of 0% and speed was initially increased every 4 minutes by 1km.h-1. Upon reaching the 4mM lactate concentration the speed was recorded (speed 4mM).Once a blood lactate concentration of 4mM had been achieved the speed was increased by 1km.h-1 every minute until the participant could not longer go on. A fingertip capillary blood sample was taken in the last 15 seconds of each 4 minute increment and the maximum heart rate was taken as the highest rate recorded prior to exhaustion.

The second test was a self-paced 10 km run controlled by the athlete on the treadmill. An average speed was taken from the time trial (speed10km) and recorded.

All of the data was recorded and plotted on graphs to determine any relationships.

The standard deviations for the three factors (speed 4mM, speed10km and HR max) were also calculated.

The major findings of the results show that there is a relationship between level of blood lactate tolerance and the ability to perform better endurance events such as the 10 km time trial. The athlete’s who demonstrated a higher blood lactate threshold performed better on the 10 km than the athlete’s who had lower lactate thresholds.

An endurance athlete’s performance depends on how fast they can run before reaching a blood concentration level of 4mM. This investigation has shown that lactate testing is a “highly scientific way of looking inside the body during exercise to see exactly what is going on” (Cuttingedge 2003). In summary, the investigation shows if an athlete can increase his/her lactate threshold they can obtain their optimum performance.