Table 4. Mean values (± SD) for HR-based method: time spent and percentage of time spent in each intensity zone by groups.
Periods Forwards (n = 22) Backs (n = 24) p-value ES (Cohen’s d)
Time spent (min)
(Percentage of time spent, %)		 Average %
of HRmax		 80.4 ± 7.2 81.6 ± 8.0 .452 Unclear
(- .3 ± .6)
< 71%
HRmax		 6.5 ± 8.4
(13.7 ± 17.7)		 7.7 ± 8.9
(16.0 ± 18.9)		 .697
(.704)		 Unclear
- .2 ± .9
(-.2 ± .8)
71-78%
HRmax		 9.1 ± 3.8
(12.8 ± 7.7)		 6.1 ± 3.8 *
(19.0 ± 8.3)		 .018
(.016)		 Moderate
1.0 ± .6
(1.0 ± .6)
78-85% HRmax 12.8 ± 4.6
(26.8 ± 9.5)		 12.1 ± 4.9
(25.3 ± 10.0)		 .468
(.540)		 Unclear
.2 ± .4
(.2 ± .6)
85-92% HRmax 18.1 ± 6.7
(37.9 ± 13.7)		 10.8 ± 7.3 **
(22.8 ± 14.8) **		 .004
(.004)		 Large
1.2 ± .6
(1.2 ± .6)
>92%
HRmax		 4.0 ± 7.5
(8.5 ± 14.8)		 8.1 ± 8.2
(17.2 ± 17.5)		 .094
(.091)		 Moderate
- .8 ± .7
(- .8 ± .7)
HHRE
(>85% HRmax)		 22.2 ± 11.4
(46.4 ± 24.0)		 19.0 ± 12.4
(40.2 ± 26.1)		 .388
(.432)		 Unclear
.4 ± .8
(.4 ± .8)
* Significant difference between forwards and backs, * p<0.05;** p<0.01.In the table, the top values represent absolute values for the time spent (min) during one full half period (independently of 1st or 2nd half), and the values in brackets correspond to the percentage of time spent in each HR intensity zones. %HRmax: percentage of maximal heart rate; HHRE: high heart rate exertion; ES: effect size (Cohen’s d) presented with 90% confidence interval.