Abstract
The purpose of this study was to examine the control of endurance training, using heart rate (HR) and blood lactate (La) analysis. This was done using three experiments covering the sports of endurance running, rowing and triathlon. The first aimed to establish a time efficient, incremental protocol for determining blood lactate profiles. The second examined control of training using running speed or HR in the laboratory and field. The third compared lactate threshold (Tlac) HRs between cycling and running in triathletes. A continuous 4 minute incremental (4I) protocol was compared with discontinuous 6 and 8 minute protocols, ANOVA with repeated measures revealed that there was no significant difference in HR and La measurements between the protocols. Subsequently, 4I was compared with a similar 3 minute (3I) version. Despite higher HR and La noted during the later stages of 41, the EDR - La relationship was unaffected by the protocol used. The 3I is a suitable, time efficient method of assessment. HR prescribed from 3I was compared with running speed to control training at maximal steady state blood lactate (MSS) in well-trained runners. HR appeared the better means of training control, where increased lactate within training sessions was less frequent than in the speed controlled sessions. The process of HR control during MSS training in the laboratory was also examined in elite junior rowers. In 9 out of 10 sessions MSS was not exceeded. A total of 80 other training sessions were also analysed. Thirty training sessions were performed by trained runners and 50 by trained rowers. Thirty four sessions were aimed at base endurance (BE) and 46 aimed at MSS intensity. In 20% of cases, athletes exceeded their prescribed HR. In all, 96% of the sessions were predicted correctly as either steady state or non-steady state on the basis of observed HR. HR from 3I was deemed an acceptable means of intensity control to avoid non-stable La. HR at Tlac and 2 mmo1.1-1 of blood La during 31 of both running and cycling exercise was compared in well-trained triathletes. In both cases mean HR was higher during running (t= 7.6, d.f = 15, p<0.001 and t = 7.6, d.f = 15, p<0.05, respectively). The mean difference in HR at Tlac was 13.4 b.min-1 with a range of 0 to 26. Separate tests should, therefore, be used for each mode of exercise in triathletes. In summary, it was concluded that a 3 minute incremental protocol is valid for the determination of blood lactate profiles and the prescription of HR for subsequent training prescription. Also, HR can predict blood lactate conditions during training sessions in well-trained runners and rowers. The HR for set training zones is likely to vary according to the mode of exercise employed.