Table 1.
Descriptive statistics of measured variables
| “hard-and-fast” instruction |
“fast” instruction |
Global effect | ||||
|---|---|---|---|---|---|---|
| Test | Retest | Test | Retest | |||
| Fmax (N) | Mean ± SD | 697.7 ± 117.2 | 693.4 ± 120.5 | 698.4 ± 128.6 | 688.6 ± 128.7 | Instruction: NS |
| CV (95% CI) | 3.6 (2.7 – 5.2) | 2.8 (2.1 – 4.1) | Session: NS | |||
| ICC (95% CI) | 0.96 (0.91 – 0.99) | 0.98 (0.95 – 0.99) | Interaction: NS | |||
| RMSFmax (μV) | Mean ± SD | 352.5 ± 114.8 | 350.8 ± 123.5 | 333.2 ± 192.0 | 319.6 ± 98.8 | Instruction: 0.057 |
| CV (95% CI) | 6.4 (4.8 – 9.4) | 9.1 (6.8 – 13.5) | Session: NS | |||
| ICC (95% CI) | 0.97 (0.94 – 0.99) | 0.93 (0.83 – 0.97) | Interaction: NS | |||
| RFDmax (N·s-1) | Mean ± SD | 3917 ± 907 | 4053 ± 855 | 5880 ± 1066 | 5597 ± 808 | Instruction: ** |
| CV (95% CI) | 16.2 (12.1 – 24.5) | 7.3 (5.5 – 10.9)§ | Session: NS | |||
| ICC (95% CI) | 0.56 (0.16 – 0.80) | 0.84 (0.64 – 0.93)§ | Interaction: NS | |||
| RMSRFDmax (μV) | Mean ± SD | 239.4 ± 95.2 | 230.4 ± 102.9 | 281.9 ± 105.2 | 264.5± 114.3 | Instruction: * |
| CV (95% CI) | 9.6 (7.2 – 14.3) | 10.4 (7.8 – 15.5) | Session: * | |||
| ICC (95% CI) | 0.95 (0.89 – 0.98) | 0.93 (0.83 – 0.97) | Interaction: NS | |||
| RMAmax (μV·s-1) | Mean ± SD | 7986 ± 3690 | 7963 ± 4185 | 11854 ± 3874 | 11394 ± 3855 | Instruction: ** |
| CV (95% CI) | 22.3 (16.6 – 34.2) | 9.8 (7.3 – 14.6)§ | Session: NS | |||
| ICC (95% CI) | 0.85 (0.65 – 0.94) | 0.94 (0.85 – 0.98)§ | Interaction: NS | |||
| EMDmax (ms) | Mean ± SD | 44.53 ± 5.97 | 43.37 ± 5.03 | 42.28 ± 6.56 | 42.35 ± 6.12 | Instruction: * |
| CV (95% CI) | 7.0 (5.3 – | 10.4) | 10.3 (7.7 – 15.4) | Session: NS | ||
| ICC (95% CI) | 0.74 (0.45 – 0.89) | 0.61 (0.24 – 0.83) | Interaction: NS | |||
| T25-50% (ms) | Mean ± SD | 60.62 ± 23.29 | 57.53 ± 16.01 | 33.97 ± 9.03 | 36.77 ± 10.94 | Instruction: ** |
| CV (95% CI) | 24.6 (18.3 – 37.9) | 9.5 (7.1 – 14.1)§ | Session: NS | |||
| ICC (95% CI) | 0.65 (0.30 – 0.84) | 0.90 (0.76 – 0.96)§ | Interaction: NS | |||
Fmax: maximal voluntary force; RMSFmax: RMS amplitude at Fmax; RFDmax: maximal rate of force development; RMSRFDmax: RMS amplitude at RFDmax; RMAmax: maximal rate of muscle activity; EMDmax: maximal electromechanical delay; T25-50%: time elapsed between achieving 25% and 50% of Fmax; CV: coefficient of variation; ICC: intraclass correlation coefficient; 95% CI: 95% confidence interval. §: Above (ICC) or below (CV) the 95% CI observed from the hard-and-fast instruction *: p < 0.05, **: p < 0.001, NS: non-significant (p > 0.05)