title: The measurement of lactate threshold in resistance exercise: a comparison of methods.
abstract: Resistance incremental tests (IT) make it possible to determine critical metabolic and cardiovascular changes, such as the lactate threshold (LT). Different methods are frequently used to improve the exactness of LT identification. The objective of the study was to identify LT by four different methods (visual inspection, log-log, algorithmic adjustment and QLac) during resistance exercise and to evaluate which methods present more precision. Twelve men performed a maximal IT on the leg press at relative intensities of 10%, 20%, 25%, 30%, 35%, 40%, 50%, 60%, 70%, 80% and 90% of 1RM with 1-min stages. During the 2-min interval between stages, capillary blood was collected for blood lactate analysis. LT was detected using each of the four methods. The intensity of LT by visual inspection method was 26·9 (5·2)% of 1RM, adjustment algorithmic method was 27·8 (3·6)% of 1RM, log-log method was 23·3 (3·5)% of 1RM and QLac method was 31·6 (9·8)% of 1RM, with significant difference only between log-log and QLac methods. Bland and Altman analysis shows better concordance for visual inspection versus adjustment algorithmic methods. The visual inspection, algorithmic and log-log methods detected the LT at the same intensity. The mathematical models, specially the algorithmic method, provide more precision.
authors.affiliation: Programa de Pós-Graduação Interunidades Bioengenharia, EESC/FMRP/IQSC, USP, São Carlos, SP, Brasil. nunosfrade@gmail.com
authors.forename: Nuno Manuel Frade
authors.initials: NM
authors.lastname: de Sousa
authors.forename: Rodrigo Ferro
authors.initials: RF
authors.lastname: Magosso
authors.forename: Guilherme Borges
authors.initials: GB
authors.lastname: Pereira
authors.forename: Richard Diego
authors.initials: RD
authors.lastname: Leite
authors.forename: Vivian Maria
authors.initials: VM
authors.lastname: Arakelian
authors.forename: Arlindo Neto
authors.initials: AN
authors.lastname: Montagnolli
authors.forename: Sérgio Andrade
authors.initials: SA
authors.lastname: Perez
authors.forename: Vilmar
authors.initials: V
authors.lastname: Baldissera
mesh_terms: D000328:Adult; D000465:Algorithms; D015308:Anaerobic Threshold; D000704:Analysis of Variance; D006801:Humans; D019344:Lactic Acid / Q000097:blood*; D016014:Linear Models; D008297:Male; D015233:Models, Statistical; D009119:Muscle Contraction; D018482:Muscle, Skeletal / Q000378:metabolism*; D015203:Reproducibility of Results; D055070:Resistance Training; D013997:Time Factors; D055815:Young Adult
chemical_list: D019344:Lactic Acid