Maximal Oxygen Uptake, Muscular Oxidative Capacity, and Ventilatory Threshold in Amateur Triathletes: Eight-Month Training Follow-Up

Abstract

Mateus Guilherme Calixto Assis,1 José Geraldo Gomes Barbosa Junior,2 Aldo Seffrin,2 Vinícius Ribeiro dos Anjos Souza,2 Lavínia Vivan,2 Mila Alves Matos Rodrigues,3 Claudio André Barbosa de Lira,3 Rodrigo Luiz Vancini,4 Beat Knechtle,5 Katja Weiss,5 Marilia Santos Andrade6 1Department of Orthopedics and Traumatology, Federal University of São Paulo, São Paulo, Brazil; 2Postgraduate Program in Translation Medicine, Federal University of São Paulo, São Paulo, Brazil; 3Human and Exercise Physiology Division, Federal University of Goiás, Goiás, Brazil; 4Center for Physical Education and Sports, Federal University of Espírito Santo, Espírito Santo, Brazil; 5Institute of Primary Care, University of Zurich, Zurich, Switzerland; 6Department of Physiology, Federal University of São Paulo, São Paulo, BrazilCorrespondence: Beat Knechtle, Medbase St. Gallen Am Vadianplatz, Vadianstrasse 26, St. Gallen, 9001, Switzerland, Tel [phone], Fax [phone], Email [email protected]: Endurance sports performance is influenced by several factors, including maximal oxygen uptake (⩒O2max), the percentage of ⩒O2max that can be sustained in endurance events, running economy, and body composition. Traditionally, ⩒O2max can be measured as an absolute value, adjusted for body mass, reflecting the athlete’s central capacity (maximal cardiac output), or adjusted for lean mass (LM), reflecting the athlete’s peripheral capacity (muscular oxidative capacity). The present study aims to evaluate absolute, total body mass, and lower limb LM-adjusted ⩒O2max, ventilatory thresholds (VT), respiratory compensation points (RCP), and body composition during two training periods separated by 8 months.Patients and Methods: Thirteen competitive amateur triathletes [seven men (40.7± 13.7 years old, 76.3± 8.3kg, and 173.9± 4.8cm) and six women (43.5± 6.9 years old, 55.0± 2.7kg, 164.9± 5.2cm)] were evaluated for body composition with dual-energy X-ray absorptiometry and ⩒O2max, VT, RPC, and maximal aerobic speed (MAS) with a cardiorespiratory maximal treadmill test.Results: The absolute ⩒O2max (p = 0.003, d = 1.05), body mass–adjusted ⩒O2max (p < 0.001, d = 1.2859), and MAS (p = 0.047, d = 0.6139) values differed significantly across evaluation periods. Lower limb LM–adjusted ⩒O2max (p = 0.083, d = − 0.0418), %⩒O2max at VT (p = 0.541, d = − 0.1746), speed at VT (p = 0.337, d = − 0.2774), % ⩒O2max at RCP (p = 0.776, d = 0.0806), and speed at RCP (p = 0.436, d = 0.2234) showed no difference.Conclusion: The sensitivities of ⩒O2max adjusted for body mass and ⩒O2max adjusted for LM to detect changes in physical training state differ. Furthermore, decreases in physical fitness level, as evaluated by ⩒O2max values, are not accompanied by changes in VT.Keywords: amateur triathletes, skeletal muscle oxidative capacity, triathlon, performance

Keywords

• amateur triathletes
• skeletal muscle oxidative capacity
• triathlon
• performance