Cardiorespiratory Fitness Indicators in Young Athletes: Analysis for Personalized Training Programs

Abstract

This study investigates the cardiorespiratory indicators of junior athletes (16–18 years old) with a focus on aerobic (AT) and anaerobic (AnT) thresholds, maximal oxygen uptake (VO₂max), power output, and their relationship with anthropometric parameters. Testing was conducted on 26 triathletes who are candidates for Master of Sport (13 males and 13 females) using a Wattbike ergometer, a Cosmed gas analyzer, and a Polar heart rate monitor. Significant individual and gender differences in functional capabilities were observed. The mean VO₂max values were 68.7±7.2 ml/min/kg for males and 55.1±8.4 ml/min/kg for females (p <0.001), indicating differences in oxygen potential and aerobic power between the groups. The anaerobic threshold was reached at 84.3±6.1% of VO₂max on average, demonstrating high lactate tolerance and efficient use of aerobic and anaerobic energy systems. The power-to-weight ratio (W/kg) was higher in athletes with lower BMI, with values such as 6.0 W/kg at a BMI of 20.8 and 4.9 W/kg at a BMI of 15.9.
The results highlight the necessity of personalized training programs based on threshold values and anthropometric characteristics. Athletes with low AT/MAX% (<70%) should focus on aerobic endurance development, while those with critically low BMI (<18.5) require adjustments in nutrition and workload to prevent metabolic disorders. This study also proposes a methodology for integrating objective testing data into training programs to optimize young triathletes’ preparation. The findings have practical implications for coaches and sports physiologists working in endurance sports.