ABSTRACT
The main aims of this study were: 1) to compare 1-minute RMSSD measurements using
different stabilization times between them and also with the criterion; and 2)
to determine the agreement between every 1-minute RMSSD measurement with the
criterion in professional soccer players. Seven hundred eighteen HRV
measurements from professional soccer players were taken. HRV was calculated
from 5 to 10 minutes (criterion) and from 1-minute windows with different
pre-stabilization times. Friedman and post-hoc tests were applied to compare
1-minute and criterion measurements. Effect size was considered to describe
magnitude of change. To determine agreement, Spearman’s correlation was
applied, and Bland–Altman analysis was also done between each
ultra-short HRV time window and the 5-minute HRV criterion period. The 1-minute
HRV without any pre-stabilization time was the only one different from all the
other 1-minute measurements that included 1 or more minutes of pre-stabilization
(p<0.001). One-minute HRV measurements with 1 or more minutes of
pre-stabilisation were highly correlated with those for the criterion period.
One-minute HRV without pre-stabilization showed the lowest correlation and the
highest bias from the criterion. It is concluded that 1-minute HRV measurements
with a prior 1-minute or longer pre-stabilization time are valid to measure HRV
in professional male soccer players.
Key words
training status - fatigue-recovery process - HRV - professional soccer
