Londeree, B. R. (1997). Effect of training on lactate/ventilatory thresholds: A meta-analysis. Medicine and Science in Sports and Exercise, 29, 837-843.

The purpose of this investigation was to determine the effect of exercise training intensity on lactate and ventilatory thresholds in sedentary and active Ss using meta-analysis procedures. Relatively few longitudinal endurance-training studies have compared the influence of different exercise training intensities upon lactate and/or ventilatory thresholds.

The original analyses included 85 study groups from 34 studies. The dependent variable was oxygen consumption at the specified threshold, and the independent variables were training intensity (control and four intensities ranging from below threshold to near maximum) and fitness level (sedentary and conditioned). Data were analyzed statistically using appropriate methods.

Results showed that sedentary Ss improved significantly over controls. Because of different significances it was concluded that lactate threshold changes occurred and could be demonstrated more readily than ventilatory threshold changes. This suggested that metabolic adaptations, when progressing from an untrained to a trained state, occur more readily at the muscle level than in ventilatory control mechanisms.

Trained Ss showed non-significant gains. There were no significant differences among training intensities within the fitness categories. Despite the author's indication that improvements were not statistically significant, his opinion that it "was close to being so" cannot go without comment. There are no degrees of significance and so the hint that significance was "almost" demonstrated is misleading. Given this delimitation, the proposal that conditioned Ss might respond better to training intensities higher than the two threshold levels also is misleading as this statement is also based on non-significant results.

To achieve maximum values in either lactate or ventilatory thresholds, 8-12 weeks of training was needed. Further training would result in no further changes in the measures or if there were any, they would be very small.

Implications. Several implications can be derived from this meta-analysis.

• Lactate or ventilatory threshold tests, as measures of training adaptation, are best suited for assessing the progress of individuals from untrained to trained states (e.g., those states achieved through 8-12 weeks of endurance training).
• Once a moderate level of fitness is achieved, either test is not likely to be sensitive to further training adaptations (if any occur).
• The lactate threshold is a more sensitive measure of training adaptation than ventilatory threshold.
• Either threshold should not be expected to change during a year of concerted training, although there may be minor variations [possibly through measurement error]. Minor observed differences are not likely to be due to training.
• The value of using lactate and/or ventilatory thresholds for prescribing training programs for seriously training full-time athletes is negligible.

Return to Table of Contents for this issue.