A meta-analysis of the nonlinear dynamics associated with anaerobic threshold

During exercise, as the work rate increases, several physiological variables show a linear increase. As the work rate continues to increase, there is a level of intensity that results in disproportionate rate changes within these physiological reactions. It is this change in slope that has been labeled the "anaerobic threshold". The purpose of this study is to determine, through a meta-analytic procedure, the nonlinear dynamics of physiological reactions associated with the anaerobic threshold. A second purpose is to recognize these reactions as a Complex Adaptive System (CAS).; Sixty-one studies met the inclusion criteria requirements. Seventeen thresholds were identified. The most common independent variables to which the thresholds were compared are VO{dollar}sb2{dollar} max (l/min.) and % VO{dollar}sb2{dollar} max. Subgroup analysis within specific thresholds included subject fitness levels, gender, testing apparatus, and trained versus untrained subjects. Significant differences (p {dollar}le{dollar}.05) were seen in the lactate threshold between the athletic and sedentary groups. Gender differences in lactate threshold were not significant. While differences were shown between lactate and ventilatory thresholds, they were not significant.; Significant differences were shown between sexes, with females exhibiting a greater threshold value (76.3% of VO{dollar}sb2{dollar} max) than their male counterparts (74.65% of VO{dollar}sb2{dollar} max). Additionally, ventilatory threshold values were significantly greater on the treadmill (72.4%) and leg ergometer (71.84%) than the arm ergometer (46.5%). A regression analysis revealed the only threshold variable significantly associated with max VO{dollar}sb2{dollar} is the ventilatory equivalent of carbon dioxide ({dollar}rm Vsb{lcub}E{rcub}/VCOsb2) (Rsp2{dollar} =.438).; In conclusion, the results of this meta-analysis indicate the threshold variables are the result of metabolic rate increases, and thus constitute a "metabolic threshold". In addition, the correlations and interactions of the threshold variables, along with their rate changes pertaining to VO{dollar}sb2{dollar} max, meet the criteria for establishing this process as a Complex Adaptive System.