Blood Lactate Changes during Indoor Cycling

Clijsen, Ron and Taeymans, Jan and Pfister, Roger and Wuthrich, Marianne and Duquet, William (2006) Blood Lactate Changes during Indoor Cycling. In: 11th Congress of the European College of Sport sciences, July 2006 , Lausanne, Switzerland.

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Abstract

Introduction Indoor Cycling (IC) booms in European fitness centres. It is said to be an aerobic training method. Cycling frequency is determined by heavy beat music. Mostly resistance is set subjectively by the athlete while heart rate controlled training is not that common yet. The aim of this study was to investigate changes of blood lactate concentration (Lact) during an IC session with resistance set subjectively and set at a percentage of maximal heart rate (HR) estimated by the common formula 220 minus age. Methods Subjects (M=4;F=3) aged between 31 and 43 yrs were recruited in a Swiss fitness centre. They were familiar with IC. Informed consent was given. On 3 consecutive Saturdays following tests were conducted: a bike ergometer-test to assess lactate threshold (day1), a first IC session with resistance set subjectively (day2) and a second IC session that was HR controlled (day3). IC sessions took place in a group and were guided by an instructor (60min.). Per subject and per session 8 fingertip blood samples were analysed:1 at rest and 7 after different blocks of higher and lower intensity bouts. The Lactate Pro™LT1710 was used for lactate analyses. HR was monitored using Polar devices. Exhaustion was assessed using the Borg scale (6-20). SPSS 12.0 was used for statistics (ANOVA for repeated measurements). Significance was set at 5%. Results Mean HR at lactate threshold (4.0 mmol/l) was 157.0±16.8 bpm. Baseline Lact was 2.5±0.8 mmol/l at the 1st and 2.9±2.0 mmol/l at the 2nd IC session. Under conditions of subjectively set resistance mean Lact was 4.9±3.0 mmol/l after warming-up and peaked at 8.6±4.4 mmol/l (p<0.05). At each measurement moments mean Lact was above 4 mmol/l (p=0.008). Under conditions of HR controlled set resistance mean Lact was 7.0±7.3 mmol/l after warming-up and peaked at 8.0±4.3 mmol/l. However, ANOVA showed no significant changes of Lact during the IC session under HR controlled conditions (p=0.243). Under both conditions Borg and HR increased (p<0.05). Discussion Lact increases above 4 mmol/l directly after warming-up and remains high during the entire session period, indicating that intensity levels are too high for adequate aerobic training. Subjectively set resistance may lead to a significant increase in Lact with individual values above 14 mmol/l. It may be argued that this is an appropriate training method for not highly trained persons. Our data suggest that the use of individual HR monitoring devices may lead to a better management of the individual set resistances. Conclusions During an IC session the anaerobic component is dominant. Following the Indoor Cycling concept warming-up already leads to Lact concentration above the threshold. The use of individual heart rate monitoring devices may lead to a better management of the individual set resistances which may avoid significant changes in blood lactate concentration. Further research with larger numbers of participants is needed to increase statistical power.

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