A pre-season comparison of aerobic fitness and flexibility of younger and older professional soccer players.

Aerobic fitness and flexibility generally present age-related decreases, yet the influence of age on these variables in soccer players is still unknown. We obtained oxygen consumption (VO(2)) and heart rate (HR) at 12 km · h (- 1), anaerobic threshold and maximum intensities, and athletes' flexibility profiles using Flexitest (FLX). Pre-season data (2005-2011) from the 2 extreme age terciles (n=54) - YOUNGER (17-22 years old) and OLDER (27-36 years old) - of a group of 162 players from an elite Brazilian soccer club were compared. The effects of aging were also assessed by contrasting VO(2), HR and FLX linear regressions - slope and intercept - vs. age-predicted and reference values. The results were similar between the YOUNGER and OLDER terciles for VO(2max), at 62.7 ± 6.1 vs. 63.2 ± 6.2 mL · kg (- 1) · min (- 1), respectively (p=0.67), effect size (ES)=0.08, and for FLX, at 43 ± 5.9 vs. 41 ± 6.0, respectively (p=0.11, ES=0.34); the YOUNGER tercile exhibited higher values for HRmax than the OLDER tercile, at 194 ± 8.1 vs. 189 ± 8.8 b · min (- 1), (p<0.01, ES=0.59). Players in the OLDER tercile did not present an age-predicted decrease in VO(2max), whereas HRmax and FLX diminished with age as predicted. We conclude that, at least for these variables, younger and older players were effectively identical in their pre-season levels of conditioning.

Stability of relative oxygen pulse curve during repeated maximal cardiopulmonary testing in professional soccer players.

During cardiopulmonary exercise testing (CPET), stroke volume can be indirectly assessed by O(2) pulse profile. However, for a valid interpretation, the stability of this variable over time should be known. The objective was to analyze the stability of the O(2) pulse curve relative to body mass in elite athletes. VO(2), heart rate (HR), and relative O(2) pulse were compared at every 10% of the running time in two maximal CPETs, from 2005 to 2010, of 49 soccer players. Maximal values of VO(2) (63.4 ± 0.9 vs 63.5 ± 0.9 mL O(2)•kg(-1)•min(-1)), HR (190 ± 1 vs188 ± 1 bpm) and relative O(2) pulse (32.9 ± 0.6 vs 32.6 ± 0.6 mL O(2)•beat(-1)•kg(-1)) were similar for the two CPETs (P > 0.05), while the final treadmill velocity increased from 18.5 ± 0.9 to 18.9 ± 1.0 km/h (P < 0.01). Relative O(2) pulse increased linearly and similarly in both evaluations (r(2) = 0.64 and 0.63) up to 90% of the running time. Between 90 and 100% of the running time, the values were less stable, with up to 50% of the players showing a tendency to a plateau in the relative O(2) pulse. In young healthy men in good to excellent aerobic condition, the morphology of the relative O(2) pulse curve is consistent up to close to the peak effort for a CPET repeated within a 1-year period. No increase in relative O(2)pulse at peak effort could represent a physiologic stroke volume limitation in these athletes.

Stability of relative oxygen pulse curve during repeated maximal cardiopulmonary testing in professional soccer players

During cardiopulmonary exercise testing (CPET), stroke volume can be indirectly assessed by O2 pulse profile. However, for a valid interpretation, the stability of this variable over time should be known. The objective was to analyze the stability of the O2 pulse curve relative to body mass in elite athletes. VO2, heart rate (HR), and relative O2 pulse were compared at every 10 percent of the running time in two maximal CPETs, from 2005 to 2010, of 49 soccer players. Maximal values of VO2 (63.4 ± 0.9 vs 63.5 ± 0.9 mL O2•kg-1•min-1), HR (190 ± 1 vs188 ± 1 bpm) and relative O2 pulse (32.9 ± 0.6 vs 32.6 ± 0.6 mL O2•beat-1•kg-1) were similar for the two CPETs (P > 0.05), while the final treadmill velocity increased from 18.5 ± 0.9 to 18.9 ± 1.0 km/h (P < 0.01). Relative O2 pulse increased linearly and similarly in both evaluations (r² = 0.64 and 0.63) up to 90 percent of the running time. Between 90 and 100 percent of the running time, the values were less stable, with up to 50 percent of the players showing a tendency to a plateau in the relative O2 pulse. In young healthy men in good to excellent aerobic condition, the morphology of the relative O2 pulse curve is consistent up to close to the peak effort for a CPET repeated within a 1-year period. No increase in relative O2pulse at peak effort could represent a physiologic stroke volume limitation in these athletes.