Table 3.
Participants' exercise performance parameters and pre- vs. post-changes.
| Variable | Test | 4 × 30 (n = 29) | Effect size | 8 × 15 (n = 24) | Effect size | P-value 4 × 30 vs. 8 × 15 baseline | P-value 4 × 30 vs. 8 × 15 pre-post |
|---|---|---|---|---|---|---|---|
| Resting HR, beats·min−1 | Pre | 100.4 ± 14.7 | −0.22 | 96.3 ± 19.8 | 0.13 | 0.5989 | 0.3334 |
| Post | 97.0 ± 15.9 | 98.8 ± 21.0 | |||||
| Δ% | −3.39 | + 2.67 | |||||
| p-value | 0.3717 | 0.9905 | |||||
| Resting LA, mmol·L−1 | Pre | 1.3 ± 0.4 | −0.25 | 1.3 ± 0.5 | −0.09 | 0.7086 | 0.8399 |
| Post | 1.2 ± 0.4 | 1.3 ± 0.4 | |||||
| Δ% | −7.32 | −2.92 | |||||
| p-value | 0.3638 | 0.5067 | |||||
| Speed at IAT, m·s−1 | Pre | 3.00 ± 0.33 | 0.34 | 3.06 ± 0.30 | −0.12 | 0.5362 | 0.0132# |
| Post | 3.11 ± 0.30 | 3.02 ± 0.30 | |||||
| Δ% | + 3.6* | −1.43 | |||||
| p-value | 0.0116 | 0.3190 | |||||
| HR at IAT, beats·min−1 | Pre | 175.3 ± 9.8 | 0.11 | 175.0 ± 12.5 | −0.19 | 0.9087 | 0.0232# |
| Post | 176.3 ± 8.2 | 172.8 ± 10.0 | |||||
| Δ% | + 0.57 | −1.26* | |||||
| p-value | 0.3873 | 0.0346 | |||||
| Maximal speed, m·s−1 | Pre | 4.25 ± 0.55 | 0.28 | 4.37 ± 0.51 | 0.21 | 0.3935 | 0.9332 |
| Post | 4.39 ± 0.48 | 4.48 ± 0.52 | |||||
| Δ% | + 3.37* | + 2.47* | |||||
| p-value | 0.0048 | 0.0415 | |||||
| Maximal LA, mmol·L−1 | Pre | 12.7 ± 2.5 | 0.0 | 12.9 ± 2.9 | −0.08 | 0.7918 | 0.8322 |
| Post | 12.7 ± 2.6 | 12.6 ± 3.3 | |||||
| Δ% | ± 0.0 | −2.3 | |||||
| p-value | 0.9050 | 0.9447 | |||||
| Maximal RPE, Borg scale | Pre | 19.9 ± 0.2 | 0.22 | 19.9 ± 0.2 | 0.27 | 0.8939 | 0.8322 |
| Post | 20.0 ± 0.0 | 20.0 ± 0.0 | |||||
| Δ% | + 0.15 | + 0.15 | |||||
| p-value | 0.3265 | 0.3299 | |||||
| Maximal HR, beats·min−1 | Pre | 196.4 ± 7.8 | 0.13 | 197.8 ± 8.9 | −0.05 | 0.5595 | 0.1161 |
| Post | 197.4 ± 7.5 | 197.4 ± 5.4 | |||||
| Δ% | + 0.51 | −0.20 | |||||
| p-value | 0.4019 | 0.1949 | |||||
| HR recovery, beats·min−1 | Pre | −59.0 ± 15.2 | 1.14 | −55.7 ± 13.1 | 1.37 | 0.4017 | 0.5277 |
| Post | −73.6 ± 9.7 | −72.8 ± 11.5 | |||||
| Δ% | + 24.8* | + 30.7* | |||||
| p-value | <0.0001 | 0.0002 |
Data presented as mean ± SD. Changes (Δ) are presented in percent. Group 4 × 30, high-intensity interval training with 4 runs of 30 s duration; Group 8 × 15, high-intensity interval training with 8 runs of 15 s duration; HR, heart rate; HR recovery, HRmax - HR3min; LA, blood lactate concentration; IAT, individual anaerobic threshold (baseline lactate + 1.5 mmol·L−1); resting HR, HR determined before start of the exercise test; RPE, rated perceived exertion.
Significantly different from pre-intervention by within-group two-tailed paired t-test.
Significantly different by between-group two-way ANOVA. Effect sizes were calculated from means and SD (Cohen's d). All significant p-values have been highlighted.