VO2 & blood lactate data obtained from a cycle ergometry test as a guide for physical capacity
In the past, it was commonly believed that lactic acid was a waste product brought about by the process of glycolysis, involving the inadequate supply of oxygen to working muscles (Hill and Lupton 1923). This view has been greatly debated since then, with claims of anaerobic glycolysis and lactate processes ongoing even during resting levels (Gladden 2004). Attempts have been made to develop alternate parameters to analyse cardio-respiratory fitness. This has ranged from maximum oxygen consumption, blood lactate concentration (bLa) (Wasserman and Mcllroy 1964) and ventilatory efficiency (Hollman 2001), with the measurement of gas exchange becoming increasingly common along the way.
Studies on lactate threshold (LT) have increased till now, with the study of bLa during incremental exercise becoming a more significant method of diagnosing endurance performance. Examples include Faria’s (2005) study into the physiology of cycling training and Jones’ (2006) research on the physiology of the women’s marathon world record holder. Additionally, the blood lactate curve and lactate threshold (LTs) have turned out to be essential in the analysis of endurance performance. However, there is still ongoing debate surrounding the concept of LT and its physiological background. The aim of this report is to evaluate the incremental exercise LT concept and its usefulness in assessing physical endurance capacity. To note, this report will not conduct a comprehensive analysis of lactate metabolism and glycolysis.
One male participant took part in this study. The participant was 52 years old and a competitive runner. Before the start of the experiment, the participant was asked to complete an informed consent and general health screening form. Their body mass was then measured to the nearest 0.1 kg while their stature was measured to the nearest 0.01 m. The participant weighed in at 72.75 kg while their stature was 1.81 m. A heart rate monitor (Polar monitor watch, Kempele, Finland) was fitted onto the participant, making sure that their heart rate was displayed on the device. Eight Douglas bags were evacuated, with a mouthpiece and tubing attached to the first bag. The ambient (room) temperature (°C) and pressure (mmHg) were then recorded. A resting capillary blood sample was then taken to identify their resting blood lactate concentration (Lactate Pro 2, Arkray, Japan). Height of the seat of the Monark cycle ergometer (Monark cycle ergometer, Vansbro, Sweden) was adjusted so that the participant could cycle comfortably, while maintaining a knee angle of ~160-170 degrees with a down stroke pedal. Recordings of all participant characteristics were recorded into table 1 shown below.
Table 1. Participant Characteristics.
First, the participant was made to carry out a light warm-up at 60 RPM with no added load for 5 minutes. The participant then began...