Table 1

Skeletal loading exercise intervention studies in children and adolescents

ReferenceParticipants and designExercise interventionAnalytical approachResults (% 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).
Bradney et al2Boys. White.Programme: One PE teacher supervised intervention programmeCon and Ex matched for age, standing†TB: +1.2% aBMD.
n=20 Con, n=20 Ex; mean age 10.4 (0.2); ageoutside of school time. Included aerobics, soccer, volleyball, dance,height, sitting height, weight, baselineLS: +2.8% aBMD.
range 8.4-11.8 years.gymnastics, basketball, weight training.aBMD. Unpaired t tests to compare bonePF: Not measured.
All TS 1 throughout.Frequency & duration: 3 times/week; 30 minutes/session; 8 monthschanges 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 al4Girls & 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); agesupervised by research team. Each session: 100 two footed dropchange in height, change in weight, andLS: +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) groundage as covariates.PF: Not reported.
Children were randomised to Con or Ex within onereaction force for drop jumps from 61 cm height was 8.8 (0.9) timesFN: +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 al3Girls & Boys. Asian & White.Programme: School based; teachers chose activities from a variety of2 (Ex, Con) × 2 (Asian, White) × 2TB: Not significant.
n=81 Con; n=63 Ex; mean age 8.9 (0.7) years; agegames, circuits, dances which incorporated jumping. 10 tuck jumps(male, female) ANOVA to examine boneLS: 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. HierarchicalPF: Not significant.
89% of girls were TS1 and 11% were TS 2 atFrequency & duration: 3 times/week; 10-30 minutes/session; 8regression to examine effect ofFN: Not significant.
baseline; ~30% of girls were TS 2 by follow up.months.intervention when baseline bone, heightGT: BMC not significant; +1.4% aBMD.
Randomised by school: 5 Con + 5 Ex.Progression: As per fitness level of class; more challenging activitieschange, lean mass change, general
added as options after 3 months.physical activity, calcium, sex, and ethnicity controlled.
Early pubertal
Morris et al1Girls. Ethnicity not stated, schools matched forProgramme: One PE teacher supervised intervention programmeIndependent t tests to compare boneTB: +5.5% BMC; +2.3% aBMD.
ethnicity.outside of school time. Included aerobics, soccer, football, stepchange between groups. ANCOVA (withLS: 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 premenarchealFrequency & duration: 3 times/week; 30 minutes/session; 10 months.covariates) to compare adjusted changePF: BMC not significant; +3.2% aBMD.
throughout; TS 1-3.Progression: In 10 week weight training session bone between groups.FN: +4.5% BMC; aBMD not significant;
Not randomised; schools self selected: 1 Con + 1vBMD not significant.
Ex.GT: Not reported.
Blimkie et al57Girls. Ethnicity not stated.Programme: Resistance training using hydraulic machines (13Con and Ex matched for age, bodyTB: Not significant.
n=16 Con, n=16 Ex girls.exercises, 4 sets with 10-12 reps of each). Sessions supervised bymass, level of habitual physical activity.LS: Not significant.
Mean age 16.2 (0.2) years; age range 14-18researchers.Two way repeated measures ANOVAPF: Not measured.
years. All postmenarcheal (TS 4-5) at baseline.Frequency & duration: 3 times/week; session duration not stated; 6.5used to compare change in boneFN: Not measured.
Girls were randomised to Con or Ex within 1months.between groups.GT: Not measured.
highschool.Progression: Resistance increased every 6 weeks.
Witzke et al58Girls. All white.Programme: First 3 months: resistance training + plyometrics. Next 6Repeated 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 andLS: Not significant.
age range13-15 years. All postmenarcheal athopping on soft surfaces.PF: Not significant.
baseline. Con and Ex matched for age and monthsFrequency & duration: 3 times/week; 30-45 minutes/session; 9FN: Not significant.
postmenarche.months.GT: Not significant.
Not randomised; exercisers participated for PE creditProgression: 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 al5Girls. All white.Programme: Jump training sessions incorporating single and two footIndividual BMC values normalised by thePremenarcheal:
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 performedTB: Not measured.
mean age 11.0 (0.9) years (Con), 11.7 (1.3) yearsFrequency & duration: 2 times/week; 20 minutes jumpwithin each maturity group, (baselineLS: +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 (100FN: +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 al6Girls. Mixed ethnicities (primarily white + Asian).Programme: School based, cicuit training programme, integrated intoANCOVAs within maturity categories toNo significant differences between
n=70 (26 Con + 44 Ex) Prepubertal (TS 1, meanphysical education classes, supervised by classroom teachers. Allcompare bone change between groupsprepubertal Ex and Con.
age 10.1 (0.5) years).station activities incorporated jumping activities: i.e., drop jumps, star(controlling for age, maturity, baselineEarly pubertal:
n=107 (64 Con + 43 Ex) Early pubertal (TS 2 + 3,jumps, lunge jumps, hopping, plyometric jumps, jumping overbone values, change in height and/orTB: Not significant.
mean age 10.5 (0.6) years).obstacles. Average ground reaction force for various jumps rangedbone 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 ofvBMD.
jumps increased within level (50-100); and jump difficulty/height increased between levels.GT: Not significant.