Validity of Heart Rate-Based Models for Estimating Oxygen Uptake During Tennis Play

Structural and Functional Changes of the Heart in Young Adult Tennis Players

ABSTRACT

This cross-sectional observational study investigated undetermined cardiac remodeling and functional adaptation in young tennis players. Fourteen males with regular tennis training (at least three times a week, mean playing age 8.3 ± 3.8 years, tennis group, tennis) and 12 males without any racket sports engagement (the control group, [CTL]) underwent comprehensive cardiac measurements using real-time three-dimensional echocardiography, recording of baseline characteristics, blood tests, and estimation of VO2 max by 12-min running. Data were analyzed to compare the two groups. Two groups were of similar age (mean age, CTL 20.9 ± 2.4 vs. tennis 22.5 ± 4.4 years, P = 0.235) and with similar body size. Compared with the CTL, Tennis group had slower pulse rate (70.9 ± 7.0/min vs. CTL 85.5 ± 9.6/min, P < 0.001), greater VO2 max (43.4 ± 3.8 mL/Kg/min vs. CTL 33.1 ± 4.8 mL/Kg/min, P < 0.001), but similar blood levels of hematocrit, NT-pro-brain natriuretic peptide, and creatinine phosphokinase. The tennis group had greater left ventricle posterior wall thickness (0.90 ± 0.06 cm vs. CTL 0.81 ± 0.10 cm, P < 0.001), greater right ventricle (RV) volume index (77.8 ± 9.6 mL vs. CTL 64.9 ± 10.1 mL, P = 0.003), and greater left atrial volume index (26.9 ± 5.5 mL/m2 vs. CTL 21.9 ± 2.7 mL/m2, P = 0.006). The tennis group had significantly increased RV strain (free wall strain, -26.5 ± 3.7% vs. CTL -23.3 ±2.8%, P = 0.025). However, the global longitudinal strains in the left atrium and left ventricle were similar between the two groups. Cardiac remodeling in young tennis players includes right ventricular dilatation with enhanced dynamic function, an enlarged left atrium with well-preserved function, and a predominant posterior wall thickening of the left ventricle.

Determining Physiological and Energetic Demands during High-Level Pommel Horse Routines Using a Modified Method Based on Heart Rate-Oxygen Uptake Functions

This study aimed (1) to assess the validity of a modified method (Mmod) based on heart rate (HR)-oxygen uptake (VO2) regression functions to calculate total energy costs (Wtotal) and aerobic (Waer) and anaerobic alactic energy contribution (Wpcr) and (2) to analyse the physiological and energetic demands of high-level pommel horse routines (PH routines). The Mmod was developed because VO2 measurements are limited during high-level PH routines. Answering Part 1, nine male artistic gymnasts performed a PH routine where energy costs were calculated from VO2 measurements and then compared with energy costs determined from the HR- VO2 regressions of Mmod's two additional tests. Using the concordance correlation coefficient (CCC) and Deming regression, Waer (CCC = 0.955), Wpcr (CCC = 0.999), and Wtotal (CCC = 0.990) show substantial to almost perfect validity without constant or proportional bias. Data from eight further gymnasts performing a high-level PH routine and a graded exercise test (GXT), as well as four data sets from Part 1, were used to determine physiological and energetic demands using Mmod. VO2 and HR during PH routines reached 86.1% and 90.4% of the maximal values during GXT. Wpcr was 47.0%, anaerobic lactic energy contribution (Wblc) was 29.7%, and Waer was 23.3% of Wtotal required during PH routines. Summarising the energetic demands of high-level PH routines, they are mainly anaerobic, where Wpcr provides the largest energy share. Waer provides a substantial part of Wtotal and should therefore also be specifically trained.