TABLE 4.
Association of athletic performance with VDBP, free, and bioavailable 25-(OH)D concentration by multiple regression analyses* in indoor players (n = 16).
| Physical fitness test variables | VDBP [µmol/L] | Free 25-(OH)D M1 [pg/mL] | Free 25-(OH)D M2 [pg/mL] | Bioavailable 25-(OH)D [ng/mL] | ||||
|---|---|---|---|---|---|---|---|---|
| ß (95% CI) | p-value | ß (95% CI) | p-value | ß (95% CI) | p-value | ß (95% CI) | p-value | |
| VO2max (ml/kg/min) | 0.144 (−0.502–−0.791) | 0.66 | 0.066 (−0.585–−0.718) | 0.84 | 0.066 (−0.586–−0.718) | 0.84 | 0.093 (−0.557–−0.744) | 0.78 |
| Handgrip strength L (kg) | 0.066 (−0.457–−0.589) | 0.80 | 0.456 (−0.010–−0.922) | 0.05 | 0.459 (−0.007–−0.924) | 0.05 | 0.427 (−0.047–−0.901) | 0.077 |
| Handgrip strength R (kg) | 0.154 (−0.363–−0.672) | 0.56 | 0.425 (−0.050–−0.899) | 0.079 | 0.429 (−0.044–−0.903) | 0.075 | 0.404 (−0.075–−0.883) | 0.10 |
| Jump height (cm) | −0.259 (−0.765–−0.247) | 0.32 | 0.668 (0.278–−1.058) | <0.001 | 0.670 (0.280–−1.059) | <0.001 | 0.635 (0.230–−1.039) | 0.002 |
| Peak force (N) | 0.274 (−0.230–−0.778) | 0.29 | 0.227 (−0.283–−0.737) | 0.38 | 0.235 (−0.274–−0.744) | 0.37 | 0.179 (−0.336–−0.695) | 0.50 |
| Peak velocity (m/s) | −0.230 (−0.740–−0.280) | 0.38 | 0.633 (0.227–−1.038) | 0.002 | 0.635 (0.230–−1.040) | 0.002 | 0.596 (0.176–−1.017) | 0.005 |
| Peak power (W) | 0.091 (−0.431–−0.613) | 0.73 | 0.562 (0.128–−0.995) | 0.011 | 0.568 (0.137–−0.999) | 0.010 | 0.524 (0.077–−0.97) | 0.021 |
| RSImod (m/s) | −0.216 (−0.728–−0.295) | 0.41 | 0.580 (0.154–−1.007) | 0.008 | 0.581 (0.154–−1.007) | 0.008 | 0.552 (0.115–−0.99) | 0.013 |
| Peak force (N/kg) | −0.021 (−0.545–−0.503) | 0.94 | 0.131 (−0.388–−0.650) | 0.62 | 0.133 (−0.386–−0.653) | 0.61 | 0.098 (−0.424–−0.619) | 0.71 |
| Peak power (W/kg) | −0.183 (−0.698–−0.332) | 0.49 | 0.773 (0.440–−1.105) | <0.001 | 0.775 (0.444–−1.106) | <0.001 | 0.750 (0.403–−1.096) | <0.001 |
| Peak propulsive force/kg (N/kg) | −0.018 (−0.541–−0.506) | 0.95 | 0.159 (−0.358–−0.676) | 0.55 | 0.162 (−0.355–−0.679) | 0.54 | 0.126 (−0.393–−0.646) | 0.63 |
| AVG propulsive force/kg (N/kg) | −0.042 (−0.565–−0.481) | 0.88 | 0.612 (0.198–−1.026) | 0.004 | 0.614 (0.200–−1.027) | 0.004 | 0.602 (0.184–−1.020) | 0.005 |
| Peak propulsive power/kg (W/kg) | −0.170 (−0.686–−0.346) | 0.52 | 0.773 (0.440–−1.105) | <0.001 | 0.775 (0.444–−1.106) | <0.001 | 0.751 (0.405–−1.097) | <0.001 |
| AVG propulsive power/kg (W/kg) | −0.195 (−0.709–−0.319) | 0.46 | 0.713 (0.346–−1.080) | <0.001 | 0.716 (0.350–−1.082) | <0.001 | 0.683 (0.300–−1.065) | <0.001 |
*Statistically significant variables were adjusted for age, body mass, and body fat; ß, unstandardized coefficient; 95% CI, confidence interval; VDBP, vitamin D binding protein; VO2max, maximal oxygen uptake; L, left; R, right; CMJ, countermovement vertical jump; AVG, average; M1, equations by Bikle et al. (1986); M2, equations by Vermeulen et al. (1999). Bold values are statistically significant.