Abstract:
The aims of this study were to examine the cardiovascular response
to recreational 5-a-side indoor-soccer (5v5) matches (5v5 study, 5v5S, n = 15) and
to assess the validity of using heart rate (HR) to estimate oxygen uptake (VO2)
demands during actual game-play (validity study, VS, n = 16) in young subjects (age
16.8±1.5 years). Game responses during 5v5S were assessed during 30 min matches
using short-range telemetry heart-rate monitors. In VS games (12 min), VO2 and HR
were monitored with a portable gas analyser (K4b2, COSMED, Rome, Italy). Individual
HR—VO2 relationships were determined from a laboratory treadmill run to exhaustion
(VS) and a multistage shuttle running fitness test (5v5S) using K4b2. Results
showed that 5v5 elicits 83.5±5.4 and 75.3±11.2% of HRpeak and VO2peak, respectively.
Ninety-one percent of the playing time (30 min) was spent at HR higher than
70% of HRpeak. In VS match, gas analyses revealed that only 71% of HR variance was
explained by VO2 variations. However, playing at approximately 70% of HRpeak elicited
51.6±11.2% of VO2peak. Group actual versus predicted VO2 values demonstrated no
significant differences (p > 0.05), however, large confidence limits were observed
(+6.20 and −10.53 ml kg−1 min−1). These results show that HR and VO2 responses
to recreational 5v5 soccer in young athletes are similar to the exercise intensities
recommended by ACSM for promoting cardiovascular health and suggest that HR
is valid to prescribe and monitor aerobic intermittent exercise. These results also
show that HR measures are acceptable for estimating VO2 during intermittent exercise
when assessing large groups, but show that large estimation errors can occur at
the individual level.
