Kerry J Mackelvie

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We compared 7-month changes in bone structural properties in pre- and early-pubertal girls randomized to exercise intervention (10-minute, 3 times per week, jumping program) or control groups. Girls were classified as prepubertal (PRE; Tanner breast stage 1; n = 43 for intervention [I] and n = 25 for control [C]) or early-pubertal (EARLY; Tanner stages 2(More)
Exercise during growth has a positive influence on bone mineral accrual, yet little is known about how bone geometry and strength adapt to loading during growth. Our primary objective was to compare changes in proximal femur bone geometry and strength between 31 prepubertal (Tanner Stage 1) boys who participated in a school-based, high-impact circuit(More)
OBJECTIVE Childhood weight-bearing physical activity is recognized as an important determinant of peak bone mass, and physical activity intervention may represent a feasible strategy for primary prevention of osteoporosis. Previous school-based exercise interventions have all been of <10 months in duration. We implemented a high-impact, circuit-based,(More)
OBJECTIVE To evaluate the effects of an elementary school-based physical education exercise intervention program on bone mineral accrual in prepubertal and early pubertal girls. STUDY DESIGN A total of 14 schools were randomly assigned to control (C) and intervention (I) groups. Girls in the I group completed a 10-minute, 3 times per week circuit of(More)
We examined the effects of a 7-month jumping intervention (10 minutes, 3 times per week) on bone mineral gain in prepubertal Asian and white boys (10.3+/-0.6 years, 36.0+/-9.2 kg) at 14 schools randomized to control (n = 60) and intervention (n = 61) groups. Intervention and control groups had similar mean baseline and change in height, weight, lean mass(More)
This systematic review examines and compares the bone mineral changes in children and adolescents, as measured by dual energy x ray absorptiometry, reported in exercise intervention studies. The effects of hormonal factors and growth on bone mineral change during puberty are examined, and the possibility of a critical period during which bone is especially(More)
OBJECTIVE Increased physical activity is an integral part of weight loss programs in adolescents. We prospectively investigated the effects of exercise on glucagon-like peptide-1 (GLP-1) concentrations and on appetite markers. METHODS AND PROCEDURES Normal weight (NW) and at risk of overweight/overweight (OW) male adolescents (n = 17/gr) underwent five(More)
CONTEXT Increased physical activity is an integral part of weight loss programs in adolescents. We hypothesized that exercise could affect appetite-regulating hormones and the subjective desire to eat, which could partly explain the poor success rate of the existing interventions. OBJECTIVE The objective of this study was to investigate prospectively the(More)
BACKGROUND Mechanical loading during childhood plays a critical role in normal growth and development of the skeleton. Ground reaction forces (GRFs) may provide a surrogate measure for the strain experienced by bone on landing and at take off. However, there appear to be no paediatric studies that assess GRFs across a variety of loading activities. (More)
Conventional density measures by dual-energy X-ray absorptiometry (DXA) are confounded by increases in bone size and do not assess bone geometry. We assessed precision of magnetic resonance imaging (MRI) and used MRI, DXA, and hip structure analysis (HSA) to assess 7-mo changes in bone structure at the femoral neck in 18 prepubertal girls. At baseline,(More)