Are there reliable primary indicators of cardiorespiratory fitness in physically active students?

Cardiorespiratory fitness is a central component of preventive sports medical assessments and plays a crucial role in early identification of health risk factors in asymptomatic populations as well as evaluating physical performance. Preventive examinations in sports medicine frequently include the assessment of Handgrip-Strength (HGS), International Physical Activity Questionnaire (IPAQ), or Medical History Interviews (MHI). The aim of this study is to investigate whether one of these can serve as a valid surrogate marker for cardiorespiratory fitness. A total of 552 university students (mean age: 21.0 ± 3.79 years (37.5% male) underwent a standardized sports medical and motor performance assessment including Cardiopulmonary Exercise Testing (CPET) on a bicycle ergometer, IPAQ, HGS testing, and a structured MHI. Associations between VO2peak and the proposed surrogate markers were analysed, controlling for sex and body weight. The parameters with the highest explanatory values were HGS (R=0.439, p