Table 2.
Fixed effects and random components of the linear mixed model.
| Fixed Effects Parameter Estimates | Random Components | ||||||
|---|---|---|---|---|---|---|---|
| Estimate | 95% CI | ||||||
| Variable | (SE) | Low–High | p-Value | Variance | ICC | ||
| Body composition | |||||||
| FFM (kg) |
Intercept | 57.3 (1.7) | 53.9–60.7 | Intercept | 38.5 | ||
| Slope | 1.1 (0.1) | 0.8–1.4 | <0.001 | Slope | 0.2 | 0.981 | |
| Residual | 0.8 | ||||||
| Bone health | |||||||
| Lumbar BMD (g/cm2) |
Intercept | 1.048 (0.019) | 1.039–1.098 | Intercept | 0.001 | ||
| Slope | 0.021 (0.008) | 0.006–0.037 | 0.022 | Slope | 4.9 × 10−4 | 0.362 | |
| Residual | 0.002 | ||||||
| Lumbar BMC (g) |
Intercept | 62.0 (2.8) | 55.6–67.4 | Intercept | 58.9 | ||
| Slope | 2.6 (0.9) | 0.8–4.3 | 0.015 | Slope | 5.3 | 0.643 | |
| Residual | 32.7 | ||||||
| Lumbar Z-score | Intercept | −0.77 (0.17) | −1.10 to −0.44 | Intercept | 0.36 | ||
| Slope | 0.04 (0.02) | 0.01–0.07 | 0.029 | Slope | 0.00 | 0.953 | |
| Residual | 0.02 | ||||||
| Femur neck BMD (g/cm2) |
Intercept | 1.093 (0.033) | 1.029–1.157 | Intercept | 0.014 | ||
| Slope | 0.012 (0.002) | 0.008–0.017 | <0.001 | Slope | 4.4 × 10−5 | 0.984 | |
| Residual | 2.2 × 10−4 | ||||||
| Femur neck BMC (g) |
Intercept | 5.8 (0.3) | 5.2–6.4 | Intercept | 1.21 | ||
| Slope | 0.1 (0.0) | 0.07–0.13 | <0.001 | Slope | 0.00 | 0.992 | |
| Residual | 0.01 | ||||||
| Total hip BMD (g/cm2) |
Intercept | 1.123 (0.032) | 1.060–1.185 | Intercept | 0.013 | ||
| Slope | 0.005 (0.002) | 0.001–0.008 | 0.029 | Slope | 3.2 × 10−5 | 0.993 | |
| Residual | 9.6 × 10−5 | ||||||
| Total hip BMC (g) |
Intercept | 40.0 (1.9) | 36.3–43.6 | Intercept | 45.2 | ||
| Slope | 0.4 (0.1) | 0.2–0.5 | <0.001 | Slope | 0.05 | 0.996 | |
| Residual | 0.2 | ||||||
| TBLH BMD (g/cm2) |
Intercept | 1.157 (0.024) | 1.109–1.204 | Intercept | 0.007 | ||
| Slope | 0.013 (0.003) | 0.008–0.019 | <0.001 | Slope | 7.2 × 10−5 | 0.986 | |
| Residual | 1.1 × 10−4 | ||||||
| TBLH BMC (g) |
Intercept | 2719 (131) | 2461–2976 | Intercept | 2.23 × 105 | ||
| Slope | 61 (9) | 43–78 | <0.001 | Slope | 902 | 0.997 | |
| Residual | 731 | ||||||
| Resting metabolic rate and energy availability | |||||||
| RMRratio | Intercept | 1.03 (0.01) | 1.01–1.05 | Intercept | 7.96 × 10−4 | ||
| Slope | −0.01 (0.01) | −0.02 to −0.0 | 0.016 | Slope | 4.80 × 10−6 | 0.275 | |
| Residual | 0.00210 | ||||||
| EA (kcal/kg FFM/day) |
Intercept | 50.1 (3.6) | 43.6–57.1 | Intercept | 122.1 | ||
| Slope | −0.7 (0.9) | −2.6 to 1.2 | 0.475 | Slope | 3.0 | 0.653 | |
| Residual | 64.8 | ||||||
| Disordered eating behavior and exercise addiction | |||||||
| EAI-Y | Intercept | 17.9 (0.7) | 16.7–19.2 | Intercept | 3.1 | ||
| Slope | −0.7 (0.2) | −1.2 to −0.3 | 0.005 | Slope | 0.1 | 0.442 | |
| Residual | 3.9 | ||||||
| Performance | |||||||
| VO2peak (mL/kg/min) |
Intercept | 61.3 (1.3) | 58.7–64.0 | Intercept | 16.7 | ||
| Slope | 2.8 (0.4) | 2.1–3.5 | <0.001 | Slope | 0.3 | 0.629 | |
| Residual | 9.9 | ||||||
| Force (Newton) |
Intercept | 2464 (106) | 2257–2671 | Intercept | 108,766 | ||
| Slope | 91 (24) | 45–137 | <0.001 | Slope | 70 | 0.649 | |
| Residual | 58,885 | ||||||
| Power (watt) |
Intercept | 1115 (49) | 1020–1210 | Intercept | 28,831 | ||
| Slope | 29 (6) | 17–41 | <0.001 | Slope | 146 | 0.912 | |
| Residual | 2797 | ||||||
Number of observations per variable: 54; groups: ID 13. BEDA-Q: Brief Eating Disorder in Athletes Questionnaire; BMC: bone mineral content; BMD: bone mineral density; BMI: body mass index; CI: confidence interval; DLS: Drive for Leanness Scale; EA: energy availability; EAI-Y: Exercise Addiction Inventory for Youth; EEE: exercise energy expenditure; EI: energy intake; FFM: fat-free mass; ICC: intra-class correlation; RMR: resting metabolic rate; SE: standard error; TBLH: total body less head; VO2peak: peak oxygen uptake.