Table 2.
Bone parameters separated by group, main effects of athletic group and mass, and subsequent contrast results where applicable.
| Variable | Group values |
Multiple linear model |
||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| C | S | T | Intercept |
Athlete |
Mass |
Full model |
||||||||||||||
| Main effect |
Contrastsa |
Main effect |
p | Adjusted R2 | ||||||||||||||||
| T versus Sb |
T versus Cb |
|||||||||||||||||||
| b | SE | p | p | η2p | b | SE | pb | b | SE | pb | b | SE | p | η2p | ||||||
| vBMC.tot (mg/mm) | 417.4 (46) | 503 (67.3) | 514.2 (58.5) | 277.8 | 63.8 | *** | *** | 0.45 | −2.3 | 18.5 | >0.99 | −91.0 | 17.9 | *** | 3.0 | 0.8 | *** | 0.25 | *** | 0.51 |
| Ar.tot (mm2) | 710.4 (118.8) | 743.2 (82.9) | 745.3 (100) | 275.3 | 104.1 | * | 5.9 | 1.3 | *** | 0.31 | *** | 0.28 | ||||||||
| Ar.ct (mm2) | 330.4 (35.6) | 415.3 (52) | 412.2 (48.7) | 235.9 | 51.6 | *** | *** | 0.51 | 9.7 | 15.0 | >0.99 | −77.50 | 14.50 | *** | 2.2 | 0.6 | ** | 0.22 | *** | 0.54 |
| vBMD.ct (mg/mm3) | 1185 (36) | 1168 (47) | 1196 (33) | |||||||||||||||||
| Ct.Thder (mm) | 4.13 (0.71) | 5.19 (0.64) | 5.18 (0.76) | 5.17 | 0.18 | *** | *** | 0.36 | 0.02 | 0.26 | >0.99 | −1.05 | 0.25 | *** | *** | 0.33 | ||||
| PsC (mm) | 94.2 (7.8) | 96.5 (5.5) | 96.6 (6.5) | 66.1 | 6.8 | *** | 0.4 | 0.1 | *** | 0.30 | *** | 0.28 | ||||||||
| EcC (mm) | 68.3 (11) | 63.9 (6.5) | 64.1 (9.3) | 40.5 | 10.7 | *** | 0.3 | 0.1 | * | 0.11 | *** | 0.09 | ||||||||
| Ix (mm4) | 41,533 (10,779) | 50,955 (11,797) | 52,202 (12,131) | −9,076 | 11,337 | 0.43 | ** | 0.23 | 1068 | 3290 | >0.99 | −9149 | 3177 | * | 780 | 141 | *** | 0.41 | *** | 0.47 |
| Iy (mm4) | 23,912 (6029) | 32,253 (9522) | 28,390 (6922) | −1,912 | 8,492 | 0.82 | ** | 0.24 | 5008 | 2464 | 0.10 | −3726 | 2380 | 0.24 | 386 | 106 | *** | 0.24 | *** | 0.33 |
| Ip (mm4) | 65,445 (16,209) | 83,208 (18,093) | 80,591 (18,254) | −10,987 | 17,321 | 0.53 | ** | 0.27 | 6076 | 5026 | 0.47 | −12,875 | 4855 | * | 1165 | 216 | *** | 0.40 | *** | 0.48 |
| Circularity | 1.14 (0.03) | 1.17 (0.05) | 1.14 (0.04) | |||||||||||||||||
When a significant effect of group was found, preplanned treatment contrasts were used to examine differences between tennis players and controls, and tennis players and sprinters only. Although age and training years were initially included as factors, they were not found to be significant for any variable hence they are not shown.
For vBMD.ct and circularity no significant predictors were found.
*p < 0.05.
**p < 0.01.
***p < 0.001.
Ar.ct = cortical bone area; Ar.tot = total bone cross-sectional area; b = model coefficient; C = control; Ct.Thder = cortical thickness; EcC = endocortical circumference; η2p = partial eta-squared; PsC = periosteal circumference; S = sprinter; SE = standard error of the coefficient; T = tennis; vBMD.ct = cortical bone mineral density; vBMC.tot = total bone mineral content.
Positive model coefficients represent greater values in tennis players.
Bonferroni correction applied due to multiple comparisons.