Skeletal loading exercise intervention studies in children and adolescents
| Reference | Participants and design | Exercise intervention | Analytical approach | Results (% difference in gain between Ex and Con, after any statistical adjustments) |
|---|---|---|---|---|
| Con, Controls; Ex, Exercisers; TS, Tanner Stage; ROI, region of interest; ANOVA, analysis of variance; ANCOVA, analysis of covariance; TB, Total body; LS, Lumbar spine; PF, Proximal femur; FN, Femoral neck; GT, Greater trochanter; BMC, bone mineral content (by dual energy x ray absorptiometry (DEXA)); aBMD, areal bone mineral density; vBMD, volumetric bone mineral density (estimated from DEXA). | ||||
| †Calculated eight month change from reported % change/month. | ||||
| ‡Bradney et al2 and Witzke et al58 were the only two studies that measured and reported change at the femoral midshaft (DEXA). | ||||
| §Heinonen et al5 was the only study that measured and reported change at the tibial midshaft (pQCT). | ||||
| Prepubertal | ||||
| Bradney et al2 | Boys. White. | Programme: One PE teacher supervised intervention programme | Con and Ex matched for age, standing | †TB: +1.2% aBMD. |
| n=20 Con, n=20 Ex; mean age 10.4 (0.2); age | outside of school time. Included aerobics, soccer, volleyball, dance, | height, sitting height, weight, baseline | LS: +2.8% aBMD. | |
| range 8.4-11.8 years. | gymnastics, basketball, weight training. | aBMD. Unpaired t tests to compare bone | PF: Not measured. | |
| All TS 1 throughout. | Frequency & duration: 3 times/week; 30 minutes/session; 8 months | changes between groups. | FN: Not measured. | |
| Randomised by school: 1 Con + 1 Ex. | duration. | GT: Not measured. | ||
| Progression: Not stated. | ‡Femoral Mid-shaft: +5.6% BMC; +5.6% aBMD, vBMD NS, +6.4% cortical thickness. | |||
| Fuchs et al4 | Girls & Boys. White. | Programme: Intervention took place outside of regular PE classes, | One factor ANCOVA; baseline bone, | TB: Not measured. |
| n=44 Con; n=45 Ex; mean age 7.5 (0.2); age | supervised by research team. Each session: 100 two footed drop | change in height, change in weight, and | LS: +3.1% BMC; +2.0% aBMD. | |
| range 5.9-9.8 years. All TS 1 throughout. | landings from 61 cm height on to a wooden floor. Mean (SD) ground | age as covariates. | PF: Not reported. | |
| Children were randomised to Con or Ex within one | reaction force for drop jumps from 61 cm height was 8.8 (0.9) times | FN: +4.5% BMC; aBMD not significant. | ||
| elementary school. | body weight. | GT: Not reported. | ||
| Frequency & duration: 3 times/week; 10 minutes jumping/session; 7 months. | ||||
| Progression: Week 1-4: Progressed from 50 jumps per session (no box), to 80 jumps per session (from box). Week 5-end : 100 jumps from 61 cm box. | ||||
| McKay et al3 | Girls & Boys. Asian & White. | Programme: School based; teachers chose activities from a variety of | 2 (Ex, Con) × 2 (Asian, White) × 2 | TB: Not significant. |
| n=81 Con; n=63 Ex; mean age 8.9 (0.7) years; age | games, circuits, dances which incorporated jumping. 10 tuck jumps | (male, female) ANOVA to examine bone | LS: Not significant. | |
| range 6.9-10.2 years. Boys were TS 1 throughout; | performed before PE class, and once in classroom each week. | changes between groups. Hierarchical | PF: Not significant. | |
| 89% of girls were TS1 and 11% were TS 2 at | Frequency & duration: 3 times/week; 10-30 minutes/session; 8 | regression to examine effect of | FN: Not significant. | |
| baseline; ~30% of girls were TS 2 by follow up. | months. | intervention when baseline bone, height | GT: BMC not significant; +1.4% aBMD. | |
| Randomised by school: 5 Con + 5 Ex. | Progression: As per fitness level of class; more challenging activities | change, lean mass change, general | ||
| added as options after 3 months. | physical activity, calcium, sex, and ethnicity controlled. | |||
| Early pubertal | ||||
| Morris et al1 | Girls. Ethnicity not stated, schools matched for | Programme: One PE teacher supervised intervention programme | Independent t tests to compare bone | TB: +5.5% BMC; +2.3% aBMD. |
| ethnicity. | outside of school time. Included aerobics, soccer, football, step | change between groups. ANCOVA (with | LS: BMC not significant; +3.6% aBMD; | |
| n=33 Con; n=38 Ex girls; mean age 9.5 (0.9) | aerobics, dance, skipping, ball games, weight training. | change in height and total body mass as | +2.9% vBMD. | |
| years; age range 9-10 years. All premenarcheal | Frequency & duration: 3 times/week; 30 minutes/session; 10 months. | covariates) to compare adjusted change | PF: BMC not significant; +3.2% aBMD. | |
| throughout; TS 1-3. | Progression: In 10 week weight training session only. | in bone between groups. | FN: +4.5% BMC; aBMD not significant; | |
| Not randomised; schools self selected: 1 Con + 1 | vBMD not significant. | |||
| Ex. | GT: Not reported. | |||
| Adolescents | ||||
| Blimkie et al57 | Girls. Ethnicity not stated. | Programme: Resistance training using hydraulic machines (13 | Con and Ex matched for age, body | TB: Not significant. |
| n=16 Con, n=16 Ex girls. | exercises, 4 sets with 10-12 reps of each). Sessions supervised by | mass, level of habitual physical activity. | LS: Not significant. | |
| Mean age 16.2 (0.2) years; age range 14-18 | researchers. | Two way repeated measures ANOVA | PF: Not measured. | |
| years. All postmenarcheal (TS 4-5) at baseline. | Frequency & duration: 3 times/week; session duration not stated; 6.5 | used to compare change in bone | FN: Not measured. | |
| Girls were randomised to Con or Ex within 1 | months. | between groups. | GT: Not measured. | |
| highschool. | Progression: Resistance increased every 6 weeks. | |||
| Witzke et al58 | Girls. All white. | Programme: First 3 months: resistance training + plyometrics. Next 6 | Repeated measures ANOVA. | TB: Not significant. |
| n=29 Con; n=27 Ex; mean age 14.6 (0.5) years; | months: plyometrics, including jumps, depth jumps, bounding and | LS: Not significant. | ||
| age range13-15 years. All postmenarcheal at | hopping on soft surfaces. | PF: Not significant. | ||
| baseline. Con and Ex matched for age and months | Frequency & duration: 3 times/week; 30-45 minutes/session; 9 | FN: Not significant. | ||
| postmenarche. | months. | GT: Not significant. | ||
| Not randomised; exercisers participated for PE credit | Progression: Weight training progressed from months 1-3: | ‡Femoral Mid-shaft: Not significant. | ||
| at 2 highschools. | repetitions, sets, and weight gradually increased. Plyometric training | |||
| progressed in jump difficulty and number of reps. | ||||
| Two maturity groups | ||||
| Heinonen et al5 | Girls. All white. | Programme: Jump training sessions incorporating single and two foot | Individual BMC values normalised by the | Premenarcheal: |
| n=58 (33 Con + 25 Ex) Premenarcheal (TS 1-3, | jumps from floor, and on and off a 30 cm box. | length of the ROI. ANCOVAs performed | TB: Not measured. | |
| mean age 11.0 (0.9) years (Con), 11.7 (1.3) years | Frequency & duration: 2 times/week; 20 minutes jump | within each maturity group, (baseline | LS: +3.3% BMC. | |
| (Ex)). | training/session; 9 months. | bone values and age as covariates). | PF: Not significant. | |
| n=68 (29 Con + 39 Ex) Postmenarcheal (TS 2-5; | Progression: Progressed gradually from two foot floor jumps (100 | FN: +4.0% BMC. | ||
| mean age 13.7 (0.9) years (Con & Ex)). | jumps) to combination one and two foot jumps from box (200 jumps). | GT: Not significant. | ||
| Not randomised; schools self-selected to 2 Ex + 3 | §Tibial Mid-shaft: Not significant. | |||
| Con. | No significant differences between postmenarcheal Ex and Con. | |||
| MacKelvie et al6 | Girls. Mixed ethnicities (primarily white + Asian). | Programme: School based, cicuit training programme, integrated into | ANCOVAs within maturity categories to | No significant differences between |
| n=70 (26 Con + 44 Ex) Prepubertal (TS 1, mean | physical education classes, supervised by classroom teachers. All | compare bone change between groups | prepubertal Ex and Con. | |
| age 10.1 (0.5) years). | station activities incorporated jumping activities: i.e., drop jumps, star | (controlling for age, maturity, baseline | Early pubertal: | |
| n=107 (64 Con + 43 Ex) Early pubertal (TS 2 + 3, | jumps, lunge jumps, hopping, plyometric jumps, jumping over | bone values, change in height and/or | TB: Not significant. | |
| mean age 10.5 (0.6) years). | obstacles. Average ground reaction force for various jumps ranged | bone area). | LS: +1.8% BMC; +1.7% aBMD. | |
| Randomised by school: 7 Ex + 7 Con. | between 3.5-5 times body weight. | PF: Not significant. | ||
| Frequency & duration: 3 times/week; 12 minutes/session; 7 months. | FN: +1.9% BMC; +1.6% aBMD; +3.1% | |||
| Progression: Levels 1-3 (~2 1/2 months at each level). Number of | vBMD. | |||
| jumps increased within level (50-100); and jump difficulty/height increased between levels. | GT: Not significant. | |||