Exercise Training at and above the Lactate Threshold in Previously Untrained Women

Abstract

We examined the effects of training at and above the lactate threshold in previously untrained women. Twenty-four untrained eumenorrheic women (age = 31.3 + 4.0 yrs, wt = 66.2±7.6 kg, ht = 166.4±5.8 cm) were assessed at baseline [during days 1-3 of the menstrual cycle (MC)] and every 4 MC after that (for 1 year) for V̇O₂ and velocity (V) at LT, fixed blood lactate concentrations (FBLC) of 2.0, 2.5, and 4.0 mM, and Max. Subjects were assigned to control (C, n = 7), at LT @ LT, trained 6 days/ week at the velocity associated with LT, n = 9) or above LT (> LT, trained 3 days/week at the velocity midway between V LT and V Max and 3 days/week at V LT, n = 8) groups. Exercise prescriptions were adjusted after each assessment and each group progressed similarly in weekly mileage. No between group differences were observed before training. After training the > LT group had significantly higher values than the C and @ LT groups for LT (p < 0.05). For FBLC of 2.0,2.5, and 4.0 mM and Max, the > LT group values were greater than the C group (p < 0.05). No differences were observed after training between the @ LT and C groups. Although the > LT group had higher V̇O₂ and V Max values than the @ LT group after training, these differences were not statistically significant. An interaction was observed with the increase in V̇O₂ and V in the > LT group being greater than the @ LT and C groups for LT and FBLC of 2.0, 2.5, and 4.0 mM and greater than the C group for Max (p < 0.05). Within group analysis revealed that both training groups showed similar increases in V̇O₂ and V at LT, FBLC of 2.0 and 2.5 mM from baseline to MC 4 (p < 0.05). At MC 8 and 12 the > LT group continued to increase V̇O₂ and V with no further change observed in the @ LT group (p < 0.05). The present data suggest that during the first 4 months of training, training at or above the LT results in similar improvements in V̇O₂ and V at LT, and FBLC of 2.0 and 2.5 mM. However, for continued improvement, in these and other parameters, some training must be above LT.

Key words

Exercise training - blood lactate - maximal oxygen uptake