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.

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