Bone. 2014 Nov;68:92-9. doi: 10.1016/j.bone.2014.08.006.

An In-school Exercise Intervention to Enhance Bone and Reduce Fat in Girls: The CAPO Kids Trial

Rossana C. Nogueira, M.Sc.1,2, Benjamin K. Weeks, Ph.D.1,2 and Belinda Beck, Ph.D.1,2

Affiliations:

1 Griffith Health Institute, Centre for Musculoskeletal Research, Gold Coast, Queensland, Australia

2School of Allied Health Sciences, Griffith University, Gold Coast, Queensland, Australia

 

Abstract:

The CAPO Kids trial was a 9-mo, controlled, school-based intervention to examine the effects of a novel, brief, high intensity exercise regime on indices of musculoskeletal and metabolic health in pre- and early pubertal girls. Methods: A total of 151 pre- and early pubertal girls (10.6 ± 0.6 years), recruited from two different schools consented to participate; 75 in the exercise group (EX) and 72 in the control group (CON). EX performed 10 min bouts of thrice-weekly jumping plus capoeira (a Brazilian sport that combines martial art with dance), along with usual physical education (PE) activities. CON continued usual PE alone. Maturity, weight, height, waist circumference, resting heart rate and blood pressure, maximal vertical jump, and aerobic capacity were determined using standard clinical and field measures. Calcaneal broadband ultrasound attenuation (BUA) and stiffness index (SI) were determined from quantitative ultrasonometry. A subsample of children also underwent DXA and pQCT measures. Prior physical activity participation and daily calcium consumption were determined from validated instruments. Results: EX girls improved BUA more than CON (+4.5% vs. +1.4%, p=0.019). Resting heart rate (-7.2% vs. -1.8%, p<0.01), maximal vertical jump (+13.4% vs. -1.2%, p<0.001), estimated maximal oxygen consumption (+10.6% vs. +1.0%, p<0.001), and waist circumference (+2.7% vs. +5.6%, p<0.001) also improved more for EX than CON. Conclusion: Ten minutes of high intensity exercise (capoeira and jumping) three times a week in the primary school setting enhances musculoskeletal and metabolic outcomes in pre- and early-pubertal girls without disrupting the academic schedule. The program, amenable to broad-scale school implementation, would confer meaningful public health benefits.

KEYWORDS: Bone mineral density; Lean mass; Obesity; Paediatric; Physical activity

PMID: 25151492

 

Supplement:

Exercise during childhood is important to optimise health in the short and long term. Although it is a common assumption that children naturally lead active lifestyles, this is not the reality. As a consequence, children are developing chronic diseases that were previously the domain of the adult population. Exercise is recommended to prevent those conditions. In addition to prevent and treat obesity, exercise in youth is known to be osteogenic, which might also prevent osteoporotic fractures later in life. It seems exercise interventions designed to enhance pediatric bone, which are brief but with high rates of loading such as jumping, may also reduce fat (1).

We developed the CAPO Kids intervention trial expecting that ten minutes of continuous high intensity movements three times a week for nine months would improve musculoskeletal as well as metabolic health. We hypothesized that girls in the exercise group would experience greater improvements in parameters of bone, muscle and fat than age- and sex- matched controls.

The activities included variations of jumps (e.g. hops, tuck-jumps, jump-squats, and star jumps) as well as capoeira-specific movements, which include the basic ginga, handstands, cartwheels, attack and defence manoeuvres. The CAPO Kids trial was incorporated into school activities, so compliance was very high (90%), and loss to follow-up was mainly related to student relocation or absence from school.

After nine months of the intervention, the participants from the intervention group improved parameters of bone health (Fig 1) and fitness as well as performance (Fig 2).

 

FIG1

Fig. 1. Nine-month change (%) in BUA and WB, tibial and radial BMD for CON and EX groups following the 9-month exercise intervention. Abbreviations: BUA = Broadband ultrasound attenuation; WB = whole body; BMD = bone mineral density. * p ≤0.05. Key: Black = control; Grey = intervention group.

 

Although we did not detect a reduction in fat mass from dual-energy x-ray absorptiometry (DXA), we observed significant improvements in waist circumference, a predictor of visceral abdominal adiposity that is closely associated with obesity and metabolic syndrome (2). Our findings suggest that the program prevented a degree of accumulation of abdominal adiposity over the course of the intervention. In addition, the significant improvements we observed in estimated VO2 max and maximal jump suggest that lean mass improvements were accompanied by meaningful performance benefits.

BUA, derived from the frequency dependence of ultrasound attenuation, has been shown to predict bone strength (3). There is some evidence that exercise may improve the BUA of children (4, 5, 6), which is supported by our findings.   We did not detect significant between-group differences in DXA- and pQCT-derived parameters of bone density, geometry or volume, but the small subsample of children available for scanning on those devices rendered power very low for those analyses.

Importance of the study: The CAPO Kids intervention improved musculoskeletal, metabolic and fat outcomes in pre- and early-pubertal girls in comparison with controls. The program was found to be enjoyable and feasible for all participants, and amenable to incorporation into a primary school day without disruption to the academic schedule.

 

FIG2

Fig. 2. Nine-month change (%) in waist circumference, vertical jump, resting heart rate and estimated VO2 max for CON and EX groups following the 9-month exercise intervention. Abbreviations: VO2 max = maximal oxygen consumption. * p ≤0.05. Key: Black = control; Grey = intervention group.

 

References:

  • Nogueira, Rossana C., Benjamin K. Weeks, and BELINDA R. Beck. Exercise to improve pediatric bone and fat: a systematic review and meta-analysis. Medicine and Science in Sports and Exercise3 (2014): 610-621.
  • Onat, A., et al. Measures of abdominal obesity assessed for visceral adiposity and relation to coronary risk.International Journal of Obesity 8 (2004): 1018-1025.
  • Wünsche, K., et al. Ultrasound bone densitometry of the os calcis in children and adolescents.Calcified Tissue International 5 (2000): 349-355.
  • Weeks, Benjamin K., Cath M. Young, and Belinda R. Beck. Eight months of regular in‐school jumping improves indices of bone strength in adolescent boys and girls: the POWER PE study.Journal of Bone and Mineral Research 7 (2008): 1002-1011.
  • Nemet, D., et al. A combined dietary-physical activity intervention affects bone strength in obese children and adolescents.International Journal of Sports Medicine 8 (2006): 666-671.
  • Lehtonen-Veromaa, M., et al. Influence of physical activity on ultrasound and dual-energy X-ray absorptiometry bone measurements in peripubertal girls: a cross-sectional study.Calcified tissue international 4 (2000): 248-254.

 

 

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