Introduction
Methods
Study design and participants
PRO-BONE study jump intervention programme
Dual-energy X-ray absorptiometry
Quantitative ultrasound
Anthropometry and maturity status
Physical activity, training characteristics and diet
Cardiorespiratory and muscular fitness
Statistical analyses
Results
Descriptive characteristics
Level | Exercise | Vest weights (kg) | Repetitions | 2Sets/day (3Rest) | 4Trainings/week | Jumps/week | 5Compliance in % and number (SD) of jumps completed | ||
---|---|---|---|---|---|---|---|---|---|
INT-SWI | INT-FOO | INT-CYC | |||||||
1 | 1CMJ | – | 20 | 3 | 3 | 180 | 90.3% | 95.3% | 91.3% |
Total level 1 (12 weeks) | 180 × 12 = | 2160 | 1949 (204) | 2059 (155) | 1971 (240) | ||||
2 | 1CMJ | 2 | 20 | 4 | 3 | 240 | 75.0% | 83.9% | 83.1% |
Total level 2 (12 weeks) | 240 × 12 = | 2880 | 2159 (434) | 2416 (444) | 2393 (454) | ||||
3 | 1CMJ | 5 | 20 | 4 | 4 | 320 | 46.0% | 56.8% | 47.1% |
Total level 3 (12 weeks) | 320 × 12 = | 3840 | 1765 (298) | 2181 (434) | 1807 (598) | ||||
Total intervention (36 weeks) | 8880 | 66.0% 5858 (1051) | 75.0% 6656 (1281) | 69.5% 6171 (1097) |
Swimmers | Footballers | Cyclists | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Total (N = 93) | Intervention (N = 19) | Control (N = 18) | Intervention (N = 15) | Control (N = 15) | Intervention (N = 14) | Control (N = 12) | ||||||
PRE | POST | PRE | POST | PRE | POST | PRE | POST | PRE | POST | PRE | POST | |
Age (years) | 14.5 ± 0.9 |
15.3 ± 0.9
| 14.7 ± 1.1 |
15.4 ± 1.1
| 13.8 ± 1.0 |
14.6 ± 1.0
| 13.7 ± 0.8 |
14.5 ± 0.8
| 14.1 ± 1.1 |
14.9 ± 1.1
| 14.1 ± 0.9 |
14.9 ± 0.9
|
Height (cm) | 170.3 ± 10.0 |
174.1 ± 9.6
| 172.8 ± 7.6 |
176.0 ± 6.9
| 160.5 ± 11.0 |
165.4 ± 11.1
| 163.3 ± 9.3 |
168.9 ± 9.1
| 168.2 ± 10.7 |
174.5 ± 8.2
| 162.7 ± 9.7 |
166.4 ± 9.6
|
Body mass (kg) | 57.2 ± 9.0 |
62.6 ± 7.8
| 60.6 ± 7.2 |
63.6 ± 7.7
| 49.3 ± 10.8 |
54.8 ± 11.6
| 49.6 ± 7.4 |
55.4 ± 7.1
| 57.7 ± 13.0 |
62.6 ± 12.2
| 51.0 ± 12.4 |
55.2 ± 13.9
|
Lean mass (kg) | 46.7 ± 9.4 |
51.2 ± 8.5
| 48.7 ± 8.2 |
51.9 ± 6.7
| 41.5 ± 10.0 |
46.1 ± 10.5
| 39.6 ± 7.4 |
44.9 ± 7.2
| 45.0 ± 7.9 |
49.5 ± 7.6
| 40.3 ± 8.6 |
44.0 ± 9.2
|
Fat mass (kg) | 7.6 ± 3.1 |
8.5 ± 2.9
| 8.2 ± 3.4 | 8.7 ± 3.8 | 5.4 ± 2.2 |
6.1 ± 2.3
| 7.1 ± 2.3 | 7.6 ± 3.5 | 9.9 ± 9.7 | 10.0 ± 9.7 | 8.1 ± 5.5 | 8.3 ± 6.5 |
Years from PHV | 1.0 ± 1.0 |
1.7 ± 1.0
| 1.2 ± 1.0 |
1.8 ± 0.9
| 0.0 ± 1.0 |
0.7 ± 1.0
| 0.1 ± 0.8 |
0.9 ± 0.8
| 0.7 ± 1.1 |
1.4 ± 1.0
| 0.3 ± 0.9 |
1.0 ± 1.0
|
Maturation (I/II/III/IV/V) (%) | (10/10/10/50/20) |
(0/0/11 /52/37)
| (0/11/16 /47/26) |
(0/0/6 /61/33)
| (10/10/43/37/0) |
(0/13/13 /40/34)
| (0/22/28 /50/0) |
(0/7/27 /40/27)
| (7/7/20 /53/13) |
(0/0/14 /43/43)
| (8/15/8 /61/8) |
(0/8/17 /42/33)
|
MVPA (min/day) | 61.3 ± 19.6 | 67.5 ± 19.6 | 59.6 ± 25.2 | 60.0 ± 18.1 | 97.7 ± 18.8 | 83.3 ± 18.5 | 89.6 ± 33.5 | 76.3 ± 22.4 | 85.6 ± 22.1 | 93.9 ± 15.7 | 88.9 ± 21.8 | 78.7 ± 13.4 |
Training volume (h/week) | 7.9 ± 3.6 |
11.8 ± 5.4
| 10.2 ± 3.1 |
12.9 ± 5.4
| 10.2 ± 1.2 |
12.0 ± 2.8
| 8.8 ± 2.0 |
10.7 ± 1.8
| 5.3 ± 2.0 |
7.9 ± 3.8
| 5.3 ± 1.6 |
8.2 ± 2.8
|
Energy intake (kcal/day) | 2534 ± 382 | 2465 ± 221 | 2603 ± 425 | 2386 ± 133 | 2237 ± 517 | 2379 ± 262 | 2419 ± 620 | 2309 ± 234 | 2320 ± 280 | 2244 ± 166 | 2221 ± 325 | 2226 ± 152 |
Protein intake (g/day) | 85.8 ± 30.9 | 89.8 ± 31.2 | 77.9 ± 28.5 | 82.8 ± 24.8 | 95.3 ± 21.6 | 97.1 ± 29.3 | 92.0 ± 35.3 | 90.1 ± 20.4 | 80.3 ± 13.3 | 88.0 ± 23.0 | 84.9 ± 28.9 | 86.4 ± 21.1 |
Calcium intake (mg/day) | 1237 ± 280 | 1118 ± 289 | 1155 ± 257 | 1109 ± 189 | 1342 ± 350 | 1231 ± 167 | 1177 ± 378 | 1179 ± 178 | 1183 ± 370 | 1253 ± 196 | 1385 ± 280 | 1279 ± 149 |
Bone mass and bone stiffness
Total (N = 93) | Swimmers | Footballers | Cyclists | |||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Intervention (N = 19) | Control (N = 18) | Intervention (N = 15) | Control (N = 15) | Intervention (N = 14) | Control (N = 12) | |||||||
PRE | 9-month adjusted gains Δ (95% CI) | PRE | 9-month adjusted gains Δ (95% CI) | PRE | 9-month adjusted gains Δ (95% CI) | PRE | 9-month adjusted gains Δ (95% CI) | PRE | 9-month adjusted gains Δ (95% CI) | PRE | 9-month adjusted gains Δ (95% CI) | |
TBLH BMC | 1892 ± 339 | 322 (276–368) | 1952 ± 325 | 251 (203–300) | 1730 ± 479 | 386 (335–438) | 1769 ± 398 | 325 (274–377) | 1848 ± 379 |
341 (290–394)
| 1582 ± 401 | 203 (145–260) |
Leg BMC | 888 ± 147 |
141 (124–159)
| 922 ± 135 | 95 (77–114) | 877 ± 246 | 150 (130–170) | 886 ± 201 | 131 (111–150) | 899 ± 170 |
148 (129–168)
| 759 ± 168 | 87 (65–109) |
Arm BMC | 290 ± 68 | 44 (37–51) | 303 ± 67 | 40 (33–47) | 226 ± 76 | 46 (38–53) | 228 ± 61 | 48 (41–56) | 271 ± 68 | 49 (40–56) | 233 ± 74 | 40 (32–48) |
Bone stiffness | 95.9 ± 12.0 |
10.3 (7.2–13.5)
| 94.5 ± 16.3 | −1.8 (−5.1–1.6) | 104.4 ± 11.9 | 15.3 (11.6–8.9) | 105.7 ± 12.4 | 10.9 (7.2–14.6) | 95.6 ± 15.6 |
9.5 (5.9–13.1)
| 93.6 ± 14 | −2.2 (−6.0–1.7) |
Physical fitness parameters
Swimmers | Footballers | Cyclists | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Total (N = 93) | Intervention (N = 19) | Control (N = 18) | Intervention (N = 15) | Control (N = 15) | Intervention (N = 14) | Control (N = 12) | ||||||
PRE | 9-month change | PRE | 9-month change | PRE | 9-month change | PRE | 9-month change | PRE | 9-month change | PRE | 9-month change | |
Counter movement jump (cm) | 46.8 ± 7.2 |
3.1 ± 0.4*
| 46.5 ± 9.4 | −0.6 ± 0.3 | 45.3 ± 6.1 |
2.2 ± 0.3
| 41.7 ± 5.8 |
1.7 ± 0.5
| 42.7 ± 5.9 |
3.2 ± 0.6*
| 45.4 ± 7.8 | 0.7 ± 0.4 |
Standing long jump (cm) | 195.8 ± 27.8 |
7.3 ± 1.8
| 191.1 ± 27.7 | 3.6 ± 2.0 | 188.1 ± 24.9 |
6.5 ± 2.6
| 184.1 ± 21.2 | 7.6 ± 3.8 | 173.8 ± 34.1 |
9.1 ± 2.2
| 180.7 ± 24.5 | 4.6 ± 3.6 |
20mSRT (shuttles) | 79.2 ± 17.6 |
6.5 ± 1.7
| 74.2 ± 24.4 | 1.9 ± 1.4 | 94.5 ± 14.4 | 3.8 ± 1.3 | 92.0 ± 21.9 | 2.9 ± 1.6 | 82.4 ± 24.2 |
6.1 ± 1.0
| 82.8 ± 19.2 | 2.8 ± 1.6 |