Effects of training at and above the lactate threshold on the lactate threshold and maximal oxygen uptake

Summary

Thirty-three college women (mean age=21.8 years) participated in a 5 d·wk⁻¹, 12 week training program. Subjects were randomly assigned to 3 groups, above lactate threshold (> LT) (N=11; trained at 69 watts above the workload associated with LT), =LT (N=12; trained at the work load associated with LT) and control (C) (N=10). Subjects were assessed for $\dot V_{O_{2\max } }$, $\dot V_{O_2 }$LT, $\dot V_{O_2 }$LT/$\dot V_{O_{2\max } }$, before and after training, using a discontinuous 3 min incremental (starting at 0 watts increasing 34 watts each work load) protocol on a cycle ergometer (Monark). Respiratory gas exchange measures were determined using standard open circuit spirometry while LT was determined from blood samples taken immediately following each work load from an indwelling venous catheter located in the back of a heated hand. Body composition parameters were determined before and after training via hydrostatic weighing. Training work loads were equated so that each subject expended approximately 1465 kJ per training session (Monark cycle ergometer) regardless of training intensity. Pretraining, no significant differences existed between groups for any variable. Post training the > LT group had significantly higher $\dot V_{O_{2\max } }$ (13%), $\dot V_{O_2 }$ (47%) and $\dot V_{O_2 }$LT/$\dot V_{O_{2\max } }$ (33%) values as compared to C (p<.05). Within group comparisons revealed that none of the groups significantly changed $\dot V_{O_{2\max } }$ as a result of training, only the > LT group showed a significant increase in $\dot V_{O_2 }$ (48%) (p<.05), while both the = LT and > LT group showed significant increases in $\dot V_{O_2 }$LT/$\dot V_{O_{2\max } }$ (= LT 16%, > LT 42% (p<.05)). No differences were found between or within groups post training for body composition parameters. It was concluded that training above the LT results in an improvement in $\dot V_{O_2 }$LT and that large improvements in $\dot V_{O_{2\max } }$ may not be required for large improvements in $\dot V_{O_2 }$.