title: Prediction of aerobic and anaerobic capacities of elite cyclists from changes in lactate during isocapnic buffering phase.
abstract: This study predicted aerobic and anaerobic capacities using relative changes of arterial blood lactate during the isocapnic buffering phase (relative [La]ISBP). Fourteen male professional cyclists (sprint-trained [n = 6] and endurance [n = 8]) performed 2 exercise sessions to exhaustion on a cycle ergometer; 1 incremental standard test to determine the isocapnic buffering phase, buffering capacities, and relative [La]ISBP and 1 supramaximal exercise test to determine maximal accumulated oxygen deficit (MAOD). The time between Lactate threshold (LT) and respiratory compensatory threshold (RCT) was considered to be the isocapnic buffering phase. Total buffering capacity was calculated as Δ[La]·ΔpH. Bicarbonate buffering was calculated as Δ[HCO3]·ΔpH, and the difference between -Δ[La]·ΔpH and Δ[HCO3]·ΔpH was considered as nonbicarbonate buffering. The lactate concentration for LT (p ≤ 0.05) and RCT (p ≤ 0.05), and relative [La]ISBP (p < 0.01) were significantly lower for endurance cyclists than for sprint-trained cyclists. A significant difference was found for bicarbonate buffering capacity between groups (p < 0.01). A significant correlation was found between relative [La]ISBP with (Equation is included in full-text article.)(r = -0.71, p ≤ 0.05) and MAOD (r = 0.73, p < 0.01). Relative [La]ISBP was useful for predicting aerobic power (R = 51%) and anaerobic capacity (R = 53%). These results demonstrated that relative [La]ISBP is an important variable in intermediary metabolism and in addition to (Equation is included in full-text article.)and LT is recommended for better evaluation of performance of athletes who show nearly equal contributions from the aerobic and anaerobic energy systems during exercise.
authors.affiliation: 1Department of Exercise Physiology, Faculty of Physical Education and Sport Science, Shahid Bahonar University of Kerman, Kerman, Iran; and 2Department of Exercise Physiology, Faculty of Physical Education and Sport Science, Tarbiat Modares University, Tehran, Iran.
authors.forename: Mohsen
authors.initials: M
authors.lastname: Hasanli
authors.forename: Rohollah
authors.initials: R
authors.lastname: Nikooie
authors.forename: Malihe
authors.initials: M
authors.lastname: Aveseh
authors.forename: Fashi
authors.initials: F
authors.lastname: Mohammad
mesh_terms: D015308:Anaerobic Threshold / Q000502:physiology*; D001642:Bicycling / Q000502:physiology*; D006801:Humans; D019344:Lactic Acid / Q000097:blood*; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology; D010807:Physical Endurance / Q000502:physiology; D005082:Physical Exertion / Q000502:physiology; D055815:Young Adult
chemical_list: D019344:Lactic Acid