TABLE 2.
Muscle-tendon related-variables (n = 12) and muscle excitation amplitude (n = 10 in gastrocnemius medialis and 8 in vastus lateralis) during maximal countermovement jumping over three surfaces (artificial turf, hybrid turf and athletic track).
| Parameters | Artificial turf |
Hybrid turf |
Athletic track |
Statistics |
|
| Mean ± SD [CI 95%] | Mean ± SD [CI 95%] | Mean ± SD [CI 95%] | P-values | η2 | |
| Gastrocnemius medialis | |||||
| Muscle-tendon unit behavior | |||||
| Shortening amplitude (cm) | −4.99 ± 0.88[−5.55;−4.43] | −4.88 ± 0.67[−5.31;−4.45] | −4.87 ± 0.74[−5.43;−4.40] | 0.68 | |
| Peak shortening velocity (cm.s–1) | −64.1 ± 8.4[−69.4;−58.7]* | −63.9 ± 6.1[−67.7;−60.0]* | −59.0 ± 7.1[−63.5;−54.4] | 0.042 | 0.10 |
| Fascicle behavior | |||||
| Shortening amplitude (cm) | −2.51 ± 0.58[−2.88;−2.14] | −2.55 ± 0.64[2.95;−2.14] | −2.49 ± 0.68[−2.92;−2.06] | 0.90 | |
| Shortening amplitude (L/Lstanding) | −0.40 ± 0.11[−0.47;−0.33] | −0.39 ± 0.11[−0.46;−0.33] | −0.39 ± 0.09[−0.45;−0.34] | 0.84 | |
| Peak shortening velocity (cm.s–1) | −16.1 ± 5.0[−19.3;−12.9] | −18.9 ± 7.8[−23.8;−13.9] | −18.2 ± 6.9[−22.5;−13.8] | 0.13 | |
| Mean shortening velocity (cm.s–1) | −8.3 ± 2.3[−9.8;−6.9] | −9.4 ± 2.5[−11.0;−7.8] | −8.9 ± 3.0[−10.8;−7.1] | 0.16 | |
| Muscle-tendon unit gearing | 4.4 ± 1.5[3.4;5.3] | 3.9 ± 1.6[2.9;4.9] | 3.7 ± 1.5[2.8;4.6] | 0.20 | |
| Pennation angle (lowest value, deg) | 13.3 ± 1.8[11.8;14.7] | 12.8 ± 2.2[11.4;14.3] | 13.2 ± 3.0[11.8;14.7] | 0.74 | |
| Pennation angle (highest value, deg) | 29.8 ± 6.0[26.7;33.0] | 27.3 ± 5.2[24.1;30.3] | 29.5 ± 4.5[26.3;32.7] | 0.17 | |
| Changes in pennation angle (deg) | 16.6 ± 6.0[13.2;19.9] | 14.4 ± 5.5[11.1;17.8] | 16.3 ± 4.6[12.9;19.6] | 0.09 | |
| Pennation angle at 80–85% CMJ | 22.5 ± 4.4[20.7;24.4] | 19.5 ± 2.0[17.6;21.4] | 20.3 ± 2.8[18.4;22.2] | 0.09 | |
| Vastus lateralis | |||||
| Muscle-tendon unit behavior | |||||
| Lengthening amplitude (cm) | 4.71 ± 0.63[4.31;5.10] | 4.59 ± 0.70[4.12;5.03] | 4.58 ± 0.68[4.15;5.02] | 0.47 | |
| Shortening amplitude (cm) | −4.82 ± 0.47[−5.12;−4.52] | −4.85 ± 0.60[−5.23;−4.48] | −4.76 ± 0.46[−5.06;−4.47] | 0.62 | |
| Peak shortening velocity (cm.s–1) | −52.0 ± 5.6[−55.6;−48.5] | −53.8 ± 6.4[−57.9;−49.7] | −51.6 ± 5.0[−54.8;−48.4] | 0.27 | |
| Fascicle behavior | |||||
| Lengthening amplitude (cm) | 4.16 ± 1.28[3.35;4.98] | 4.42 ± 1.43[3.50;5.33] | 4.08 ± 1.98[2.83;5.34] | 0.77 | |
| Lengthening amplitude (L/Lstanding) | 0.53 ± 0.16[0.43;0.63] | 0.53 ± 0.13[0.45;0.62] | 0.47 ± 0.17[0.36;0.58] | 0.34 | |
| Shortening amplitude (cm) | −4.47 ± 1.29[−5.29;−3.65] | −4.60 ± 1.29[−5.23;−3.69] | −4.33 ± 1.62[−5.36;−3.30] | 0.94 | |
| Shortening amplitude (L/Lstanding) | −0.57 ± 0.17[−0.68;−0.46] | −0.56 ± 0.14[−0.65;−0.47] | −0.51 ± 0.16[−0.61;−0.41] | 0.43 | |
| Peak shortening velocity (cm.s–1) | −37.0 ± 15.8[−47.6;−26.4] | −33.7 ± 10.6[−40.8;−26.5] | −35.7 ± 17.5[−47.5;−24.0] | 0.65 | |
| Mean shortening velocity (cm.s–1) | −16.8 ± 5.6[−20.4;−13.3] | −18.3 ± 6.8[−22.6;−14.0] | −15.7 ± 7.1[−20.2;−11.2] | 0.39 | |
| Muscle-tendon unit gearing | 1.7 ± 0.6[1.3;2.1] | 1.8 ± 0.8[1.3;2.3] | 1.8 ± 0.9[1.2;2.4] | 0.78 | |
| Pennation angle (lowest value, deg) | 9.8 ± 2.0[8.3;11.2] | 9.4 ± 2.6[8.0;10.9] | 10.1 ± 2.9[8.6;11.5] | 0.78 | |
| Pennation angle (highest value, deg) | 20.8 ± 5.1[17.6;23.9] | 19.0 ± 4.9[15.9;22.1] | 19.2 ± 5.1[16.0;22.3] | 0.15 | |
| Changes in pennation angle (deg) | 11.0 ± 4.8[8.2;13.8] | 9.6 ± 5.0[6.8;12.4] | 9.1 ± 3.8[6.3;11.9] | 0.14 | |
| Myoelectrical activity | |||||
| Gastrocnemius medialis (%; downward phase) | 155 ± 59[114;196]* | 122 ± 55[84;160] | 100 ± 0 | 0.047 | 0.16 |
| Vastus lateralis (%; downward phase) | 127 ± 40[96;158] | 103 ± 22[86;120] | 100 ± 0 | 0.31 | |
| Gastrocnemius medialis (%; upward phase) | 129 ± 34[105;153]* | 128 ± 42[99;157] | 100 ± 0 | 0.022 | 0.18 |
| Vastus lateralis (%; upward phase) | 99 ± 25[80;118] | 107 ± 21[91;123] | 100 ± 0 | 0.64 | |
* Significantly different from athletic track. A negative value of length changes corresponds to shortening. Values are presented as mean ± standard deviation SD [confidence interval CI 95%]. Statistical significance was set at P < 0.05. Partial eta-squared η2 is a measure of the effect size with η2 < 0.06 considered as a small effect size, 0.06 < η2 < 0.14 a medium effect, and η2 > 0.14 a large effect. Muscle excitation is expressed as a percentage of the average root-mean-square values obtained for both phases (i.e., downward and upward) on the athletic track. Thus, muscle excitation amplitude on athletic track corresponds to 100%.