Continuous running at a fixed lactate threshold of 2 mmol/L resulted in variable individual responses, with mean lactate reaching 2.85 mmol/L and heart rate utilization at 92.2%.
Observational (n=15)
Does a 40-min continuous running session at a fixed lactate threshold load of 2 mmol L-1 produce consistent physiological responses in trained runners?
Continuous training based on a fixed lactate threshold leads to highly variable individual physiological responses, suggesting athletes with higher threshold performance should choose intensities more conservatively.
With Norway’s successes in middle and long-distance running, lactate-guided threshold training has regained importance in recent years. Therefore, the aim of the present study was to investigate the individual responses on common monitoring parameters based on a lactate-guided conventional training method. In total, 15 trained runners (10 males, 5 females; 18.6 ± 3.3 years; VO2max: 59.3 ± 5.9 mL kg−1 min−1) completed a 40-min continuous running session at a fixed lactate threshold load of 2 mmol L−1. Lactate (La), oxygen uptake (VO2), heart rate (HR), and rating of perceived exertion (RPE) were recorded. The chosen workload led to lactate values of 2.85 ± 0.56 mmol L−1 (range: 1.90–3.80), a percentage of VO2max utilization (%VO2max) of 79.2 ± 2.5% (range: 74.9–83.8), a percentage of HRmax utilization (%HRmax) of 92.2 ± 2.5% (range: 88.1–95.3), and an RPE of 6.1 ± 1.9 (range: 3–10) at the end of the running session. Thereby, the individual responses differed considerably. These results indicate that a conventional continuous training method based on a fixed lactate threshold can lead to different individual responses, potentially resulting in various physiological impacts. Moreover, correlation analyses suggest that athletes with higher lactate threshold performance levels must choose their intensity in continuous training methods more conservatively (lower percentage intensity based on a fixed threshold) to avoid eliciting excessively strong metabolic responses.
Fleckenstein et al. (2023) conducted an observational in Trained runners (n=15). Continuous running at a fixed lactate threshold load of 2 mmol L−1 was evaluated on Lactate, oxygen uptake (VO2), heart rate (HR), and rating of perceived exertion (RPE) at the end of the running session. Continuous running at a fixed lactate threshold of 2 mmol/L resulted in variable individual responses, with mean lactate reaching 2.85 mmol/L and heart rate utilization at 92.2%.