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Abstract
PURPOSE OF REVIEW The goal of this review is to highlight the deficits in muscle and bone in children with cerebral palsy (CP), discuss the muscle-bone relationship in the CP population, and identify muscle-based intervention strategies that may stimulate an improvement in their bone development. RECENT FINDINGS The latest research suggests that muscle and bone are both severely underdeveloped and weak in children with CP, even in ambulatory children with mild forms of the disorder. The small and low-performing muscles and limited participation in physical activity are likely the major contributors to the poor bone development in children with CP. However, the muscle-bone relationship may be complicated by other factors, such as a high degree of fat and collagen infiltration of muscle, atypical muscle activation, and muscle spasticity. Muscle-based interventions, such as resistance training, vibration, and nutritional supplementation, have the potential to improve bone development in children with CP, especially if they are initiated before puberty. Studies are needed to identify the muscle-related factors with the greatest influence on bone development in children with CP. Identifying treatment strategies that capitalize on the relationship between muscle and bone, while also improving balance, coordination, and physical activity participation, is an important step toward increasing bone strength and minimizing fractures in children with CP.
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Affiliation(s)
- Christopher M Modlesky
- Department of Kinesiology, University of Georgia, 330 River Road, Room 353, Athens, GA, 30602, USA.
| | - Chuan Zhang
- Department of Kinesiology, University of Georgia, 330 River Road, Room 353, Athens, GA, 30602, USA
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Bone-Loading Physical Activity and Alcohol Intake but not BMI Affect Areal Bone Mineral Density in Young College-Aged Korean Women: A Cross-Sectional Study. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2019; 16:ijerph16245063. [PMID: 31842273 PMCID: PMC6950177 DOI: 10.3390/ijerph16245063] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 12/09/2019] [Accepted: 12/09/2019] [Indexed: 12/12/2022]
Abstract
The purpose of this cross-sectional study was to determine the differences in areal bone mineral density (aBMD) based on alcohol consumption behaviors, bone-loading history as assessed by a bone-specific physical activity questionnaire (BPAQ), and the body mass index (BMI). College-aged female students (N = 112) were recruited from the universities in Seoul and Gyeonggi province, South Korea. The aBMD of the lumbar spine and non-dominant side of the proximal femur (total hip, TH; femoral neck, FN; femoral trochanter, FT) were measured using dual energy X-ray absorptiometry (DXA). Alcohol consumption was determined by the frequency and amount of alcohol intake during the past 12 months using a self-reported questionnaire. The X-scan plus II was used to measure height (cm), body mass (kg), fat-free mass (FFM, kg), and % body fat. Drinking two or more times alcohol per week was associated with greater aBMD of the TH (p = 0.04–0.002) and FN (p = 0.043) compared to a lower frequency of alcohol consumption and 2–4 times per month, respectively. Based on the drinking amount per occasion, there were no significant group differences (p > 0.05) in aBMD at any of the sites. The highest group of total BPAQ had greater aBMD of the TH, FN, and FT versus the lowest (p = 0.023–0.009) and mid of total BPAQ groups (p = 0.004–0.009). Additionally, the highest group had greater aBMD of the lumbar spine compared to the mid group (p = 0.001). No significant group differences in aBMD at any of the sites were noted based on the BMI (p > 0.05). Young college-aged women with greater bone-loading physical activity showed greater aBMD at the TH, FN, FT, and lumbar spine, while a moderate alcohol intake was associated with greater aBMD of the TH and FN. These findings have clinical implications for young women who may not participate in high-impact physical activity and are binge drinkers.
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Bone Marrow Fat Physiology in Relation to Skeletal Metabolism and Cardiometabolic Disease Risk in Children With Cerebral Palsy. Am J Phys Med Rehabil 2019; 97:911-919. [PMID: 29894311 DOI: 10.1097/phm.0000000000000981] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Individuals with cerebral palsy exhibit neuromuscular complications and low physical activity levels. Adults with cerebral palsy exhibit a high prevalence of chronic diseases, which is associated with musculoskeletal deficits. Children with cerebral palsy have poor musculoskeletal accretion accompanied by excess bone marrow fat, which may lead to weaker bones. Mechanistic studies to determine the role of bone marrow fat on skeletal growth and maintenance and how it relates to systemic energy metabolism among individuals with cerebral palsy are lacking. In this review, we highlight the skeletal status in children with cerebral palsy and analyze the existing literature on the interactions among bone marrow fat, skeletal health, and cardiometabolic disease risk in the general population. Clinically vital questions are proposed, including the following: (1) Is the bone marrow fat in children with cerebral palsy metabolically distinct from typically developing children in terms of its lipid and inflammatory composition? (2) Does the bone marrow fat suppress skeletal acquisition? (3) Or, does it accelerate chronic disease development in children with cerebral palsy? (4) If so, what are the mechanisms? In conclusion, although inadequate mechanical loading may initiate poor skeletal development, subsequent expansion of bone marrow fat may further impede skeletal acquisition and increase cardiometabolic disease risk in those with cerebral palsy.
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Exercise-induced sympathetic dilatation in arterioles of the guinea pig tibial periosteum. Auton Neurosci 2019; 217:7-17. [DOI: 10.1016/j.autneu.2018.12.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Revised: 12/06/2018] [Accepted: 12/21/2018] [Indexed: 11/23/2022]
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Heinonen I, Boushel R, Hellsten Y, Kalliokoski K. Regulation of bone blood flow in humans: The role of nitric oxide, prostaglandins, and adenosine. Scand J Med Sci Sports 2018; 28:1552-1558. [PMID: 29377406 DOI: 10.1111/sms.13064] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/08/2017] [Indexed: 12/23/2022]
Abstract
The mechanisms that regulate bone blood flow (BBF) in humans are largely unknown. Animal studies suggest that nitric oxide (NO) could be involved, and in this study, we investigated the effects of inhibition of nitric oxide synthase (NOS) alone and in combination with inhibition of cyclooxygenase (COX) enzyme, thus prostaglandin (PG) synthesis on femoral bone marrow blood flow by positron emission tomography in healthy young men at rest and during one-leg dynamic exercise. In an additional group of healthy men, the role of adenosine (ADO) in the regulation of BBF during exercise was investigated by use of an adenosine receptor blocker (aminophylline). Inhibitors were directly infused into the femoral artery. Resting BBF was 1.1 ± 0.4 mL 100 g-1 min-1 and increased to almost sixfold in response to exercise (6.3 ± 1.5 mL 100 g-1 min-1 ). Inhibition of NOS reduced BBF at rest to 0.7 ± 0.3 mL 100 g-1 min-1 (P = .036), but did not affect BBF significantly during exercise (5.5 ± 1.4 mL 100 g-1 min-1 , P = .25). On the other hand, while combined NOS and COX inhibition did not cause any further reduction of blood flow at rest (0.6 ± 0.2 mL 100 g-1 min-1 ), the combined blockade reduced BBF during exercise by ~21%, to 5.0 ± 1.8 mL 100 g-1 min-1 (P = .014). Finally, the ADO inhibition during exercise reduced BBF from 5.5 ± 1.9 mL 100 g-1 min-1 to 4.6 ± 1.2 mL 100 g-1 min-1 (P = .045). In conclusion, our results support the view that NO is involved in controlling bone marrow blood flow at rest, and NO, PG, and ADO play important roles in controlling human BBF during exercise.
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Affiliation(s)
- I Heinonen
- Turku PET Centre, Turku, Finland.,Department of Clinical Physiology and Nuclear Medicine, University of Turku, Turku, Finland.,Division of Experimental Cardiology, Thoraxcenter, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - R Boushel
- School of Kinesiology, University of British Columbia, Vancouver, BC, Canada
| | - Y Hellsten
- Exercise and Sport Sciences, Section of Human Physiology, University of Copenhagen, Copenhagen, Denmark
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Prisby RD. Mechanical, hormonal and metabolic influences on blood vessels, blood flow and bone. J Endocrinol 2017; 235:R77-R100. [PMID: 28814440 PMCID: PMC5611884 DOI: 10.1530/joe-16-0666] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Accepted: 08/16/2017] [Indexed: 12/25/2022]
Abstract
Bone tissue is highly vascularized due to the various roles bone blood vessels play in bone and bone marrow function. For example, the vascular system is critical for bone development, maintenance and repair and provides O2, nutrients, waste elimination, systemic hormones and precursor cells for bone remodeling. Further, bone blood vessels serve as egress and ingress routes for blood and immune cells to and from the bone marrow. It is becoming increasingly clear that the vascular and skeletal systems are intimately linked in metabolic regulation and physiological and pathological processes. This review examines how agents such as mechanical loading, parathyroid hormone, estrogen, vitamin D and calcitonin, all considered anabolic for bone, have tremendous impacts on the bone vasculature. In fact, these agents influence bone blood vessels prior to influencing bone. Further, data reveal strong associations between vasodilator capacity of bone blood vessels and trabecular bone volume, and poor associations between estrogen status and uterine mass and trabecular bone volume. Additionally, this review highlights the importance of the bone microcirculation, particularly the vascular endothelium and NO-mediated signaling, in the regulation of bone blood flow, bone interstitial fluid flow and pressure and the paracrine signaling of bone cells. Finally, the vascular endothelium as a mediator of bone health and disease is considered.
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Affiliation(s)
- Rhonda D Prisby
- Department of KinesiologyUniversity of Texas at Arlington, Arlington, Texas, USA
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Abstract
PURPOSE The goal of the current work is to challenge the enduring notion that prepuberty is the optimum timing for maximum bone response to exercise in childhood and to present the evidence that early puberty is a more potently receptive period. METHOD The relevant literature is reviewed and the causes of the misconception are addressed in detail. RESULTS Contrary to prevailing opinion, ample evidence exists to suggest that the peripubertal years represent the developmental period during which bone is likely to respond most robustly to exercise intervention. CONCLUSION Public health initiatives that target bone-specific exercise interventions during the pubertal years are likely to be the most effective strategy to harness the increased receptiveness of the growing skeleton to mechanical loading.
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Rubio-López N, Llopis-González A, Picó Y, Morales-Suárez-Varela M. Dietary Calcium Intake and Adherence to the Mediterranean Diet in Spanish Children: The ANIVA Study. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2017; 14:ijerph14060637. [PMID: 28613243 PMCID: PMC5486323 DOI: 10.3390/ijerph14060637] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Revised: 06/06/2017] [Accepted: 06/10/2017] [Indexed: 02/07/2023]
Abstract
The aim of this study was to evaluate the relationship of dietary calcium intake with anthropometric measures, physical activity and adherence to the Mediterranean diet (MedDiet) in 1176 Spanish children aged 6-9 years. Data were obtained from "Antropometría y Nutrición Infantil de Valencia" (ANIVA), a cross-sectional study of a representative sample. Dietary calcium intake assessed from three-day food records was compared to recommended daily intakes in Spain. Anthropometric measures (weight and height) were measured according to international standards and adherence to the MedDiet was evaluated using the Mediterranean Diet Quality Index (KIDMED) test. For the total sample of children, 25.8% had inadequate calcium intake, a significantly higher prevalence in girls (p = 0.006) and inadequate calcium intake was associated with lower height z-score (p = 0.001) for both sexes. In girls, there was an inverse relationship between calcium intake and body mass index (p = 0.001) and waist/hip ratio (p = 0.018). Boys presented a polarization in physical activity, reporting a greater level of both physical and sedentary activity in comparison with girls (p = 0.001). Children with poor adherence to MedDiet, even if they consume two yogurts or cheese (40 g) daily, adjusted by gender, age, total energy intake, physical activity and father's level of education, are at risk of inadequate total calcium intake (odds ratio adjusted [ORa]: 3.36, 95% confidence interval [CI]: 1.13-9.94, p = 0.001). The intake of these dairy products was insufficient to cover calcium intake recommendations in this age group (6-9 years). It is important to prioritize health strategies that promote the MedDiet and to increase calcium intake in this age group.
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Affiliation(s)
- Nuria Rubio-López
- Unit of Public Health, Hygiene and Environmental Health, Department of Preventive Medicine and Public Health, Food Science, Toxicology and Legal Medicine, University of Valencia, 46100 Valencia, Spain.
- Biomedical Research Center Network on Epidemiology and Public Health (CIBERESP), 28029 Madrid, Spain.
| | - Agustín Llopis-González
- Unit of Public Health, Hygiene and Environmental Health, Department of Preventive Medicine and Public Health, Food Science, Toxicology and Legal Medicine, University of Valencia, 46100 Valencia, Spain.
- Biomedical Research Center Network on Epidemiology and Public Health (CIBERESP), 28029 Madrid, Spain.
| | - Yolanda Picó
- Biomedical Research Center Network on Epidemiology and Public Health (CIBERESP), 28029 Madrid, Spain.
- Environmental and Food Safety Research Group (SAMA-UV), Faculty of Pharmacy, University of Valencia, 46100 Valencia, Spain.
- Research Center on Desertification (CIDE, UV-CSIC-GV), Carretera Moncada-Náquera, 46113 Moncada, Spain.
| | - María Morales-Suárez-Varela
- Unit of Public Health, Hygiene and Environmental Health, Department of Preventive Medicine and Public Health, Food Science, Toxicology and Legal Medicine, University of Valencia, 46100 Valencia, Spain.
- Biomedical Research Center Network on Epidemiology and Public Health (CIBERESP), 28029 Madrid, Spain.
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Plaza-Carmona M, Vicente-Rodríguez G, Gómez-Cabello A, Martín-García M, Sánchez-Sánchez J, Gallardo L, Ara I. Higher bone mass in prepubertal and peripubertal female footballers. Eur J Sport Sci 2016; 16:877-83. [PMID: 26902531 DOI: 10.1080/17461391.2016.1144794] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
OBJECTIVES The main aim of this study was to compare the bone mass of female football players with controls of different pubertal stages. METHODS Sixty five girls aged 8-14 years (10.14 ± 0.1, Tanner stages I-IV) participated in the study. Twenty participants were prepubertal (10 prepubertal control) and 45 peripubertal (15 peripubertal control). All footballers trained two days per week while the control group did not perform regular physical activity outside of school. Body composition was assessed by Dual-energy X-ray absorptiometry. Analysis of covariance was performed to evaluate differences in lean and bone masses. RESULTS Significant differences in lower-body extremities lean mass (LLM) between peripubertal groups were found (P < .05). Additionally, prepubertal footballers showed higher values of bone mineral content (BMC) at the femoral neck (P < .05) while peripubertal footballers exhibited enhanced BMC at the whole-body, trochanter and Wards triangle area. Bone mineral density (BMD) was higher in footballers compared to their non-active peers at the femoral neck and intertrochanter (P < .05, respectively) while in the peripubertal footballers higher BMD values were found in almost all of the studied body sites. CONCLUSION Female footballers showed higher bone and lean masses compared to control counterparts; these differences are already detectable at prepubertal ages and more consistent after pubertal spurt.
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Affiliation(s)
- M Plaza-Carmona
- a IGOID Research Group , University of Castilla-La Mancha , Toledo , Spain
| | - G Vicente-Rodríguez
- b GENUD "Growth, Exercise, Nutrition and Development" Research Group , University of Zaragoza , Zaragoza , Spain
| | - A Gómez-Cabello
- b GENUD "Growth, Exercise, Nutrition and Development" Research Group , University of Zaragoza , Zaragoza , Spain.,c Centro Universitario de la Defensa , Zaragoza , Spain
| | - M Martín-García
- d GENUD Toledo Research Group , University of Castilla-La Mancha , Toledo , Spain
| | - J Sánchez-Sánchez
- e UCAM-Universidad Católica San Antonio de Murcia , Guadalupe , Spain
| | - L Gallardo
- a IGOID Research Group , University of Castilla-La Mancha , Toledo , Spain
| | - I Ara
- d GENUD Toledo Research Group , University of Castilla-La Mancha , Toledo , Spain
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Bajaj D, Allerton BM, Kirby JT, Miller F, Rowe DA, Pohlig RT, Modlesky CM. Muscle volume is related to trabecular and cortical bone architecture in typically developing children. Bone 2015; 81:217-227. [PMID: 26187197 PMCID: PMC5912953 DOI: 10.1016/j.bone.2015.07.014] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Revised: 05/15/2015] [Accepted: 07/13/2015] [Indexed: 11/22/2022]
Abstract
INTRODUCTION Muscle is strongly related to cortical bone architecture in children; however, the relationship between muscle volume and trabecular bone architecture is poorly studied. The aim of this study was to determine if muscle volume is related to trabecular bone architecture in children and if the relationship is different than the relationship between muscle volume and cortical bone architecture. MATERIALS AND METHODS Forty typically developing children (20 boys and 20 girls; 6 to 12y) were included in the study. Measures of trabecular bone architecture [i.e., apparent trabecular bone volume to total volume (appBV/TV), trabecular number (appTb.N), trabecular thickness (appTb.Th) and trabecular separation (appTb.Sp)] in the distal femur, cortical bone architecture [cortical volume, total volume, section modulus (Z) and polar moment of inertia (J)] in the midfemur, muscle volume in the midthigh and femur length were assessed using magnetic resonance imaging. Total physical activity and moderate-to-vigorous physical activity were assessed using an accelerometer-based activity monitor worn around the waist for four days. Calcium intake was assessed using diet records. Relationships among the measures were tested using multiple linear regression analysis. RESULTS Muscle volume was moderately-to-strongly related to measures of trabecular bone architecture [appBV/TV (r=0.81), appTb.N (r=0.53), appTb.Th (r=0.67), appTb.Sp (r=-0.71); all p<0.001] but more strongly related to measures of cortical bone architecture [cortical volume (r=0.96), total volume (r=0.94), Z (r=0.94) and J (r=0.92; all p<0.001)]. Similar relationships were observed between femur length and measures of trabecular (p<0.01) and cortical (p<0.001) bone architecture. Sex, physical activity and calcium intake were not related to any measure of bone architecture (p>0.05). Because muscle volume and femur length were strongly related (r=0.91, p<0.001), muscle volume was scaled for femur length (muscle volume/femur length(2.77)). When muscle volume/femur length(2.77) was included in a regression model with femur length, sex, physical activity and calcium intake, muscle volume/femur length(2.77) was a significant predictor of appBV/TV, appTb.Th and appTb.Sp (partial r=0.44 to 0.49, p<0.05) and all measures of cortical bone architecture (partial r=0.47 to 0.54; p<0.01). CONCLUSIONS The findings suggest that muscle volume in the midthigh is related to trabecular bone architecture in the distal femur of typically developing children. The relationship is weaker than the relationship between muscle volume in the midthigh and cortical bone architecture in the midfemur, but the discrepancy is driven, in large part, by the greater dependence of cortical bone architecture measures on femur length.
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Affiliation(s)
- Deepti Bajaj
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE 19713, USA
| | - Brianne M Allerton
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE 19713, USA
| | - Joshua T Kirby
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE 19713, USA
| | - Freeman Miller
- Department of Orthopedics, Nemours AI duPont Hospital for Children, Wilmington, DE 19803, USA
| | - David A Rowe
- School of Psychological Sciences and Health, University of Strathclyde, Glasgow G1 1XQ, UK
| | - Ryan T Pohlig
- Biostatistics Core Facility, University of Delaware, Newark, DE 19713, USA
| | - Christopher M Modlesky
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE 19713, USA.
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Stabley JN, Moningka NC, Behnke BJ, Delp MD. Exercise training augments regional bone and marrow blood flow during exercise. Med Sci Sports Exerc 2015; 46:2107-12. [PMID: 24658222 DOI: 10.1249/mss.0000000000000342] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
INTRODUCTION The principal nutrient artery to the femur demonstrates an increase in nitric oxide-mediated vasodilation in rats after treadmill exercise training. The present study sought to determine whether exercise training improves hindlimb bone and marrow blood flow distribution at rest and during exercise. METHODS Six 8-month old male Sprague-Dawley rats were exercise trained (ET) with treadmill walking at 15 m · min(-1) up a 15° incline for 60 min · d(-1) over a 10- to 12-wk period. Sedentary (SED) control animals were acclimated to treadmill exercise for 5 min · d(-1) during the week preceding the blood flow measurements. Blood flow to nine distinct regions of the femur, tibia, and fibula was determined at rest and during low-intensity exercise (15 m · min(-1) walking, 0° incline) using the reference sample microsphere method. RESULTS The results demonstrate an augmentation of exercise hyperemia above that observed in SED rats during exercise in only one region of the bone, the femoral diaphysis, of ET rats. However, whereas exercise hyperemia occurred in three of the nine hindlimb bone regions measured in SED rats, exercise hyperemia occurred in seven of nine regions in ET rats. CONCLUSIONS These data indicate an increase in generalized hindlimb bone and marrow blood flow during physical activity after a period of exercise training. Elevations in regional bone and marrow blood flow after training may augment medullary pressure and bone interstitial fluid flow, thus benefiting bone integrity.
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Affiliation(s)
- John N Stabley
- 1Center for Exercise Science, Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL; and 2Department of Physiology and Functional Genomics, University of Florida, Gainesville, FL
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Duckham RL, Baxter-Jones ADG, Johnston JD, Vatanparast H, Cooper D, Kontulainen S. Does physical activity in adolescence have site-specific and sex-specific benefits on young adult bone size, content, and estimated strength? J Bone Miner Res 2014; 29:479-86. [PMID: 23907819 DOI: 10.1002/jbmr.2055] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Revised: 07/18/2013] [Accepted: 07/25/2013] [Indexed: 11/06/2022]
Abstract
The long-term benefits of habitual physical activity during adolescence on adult bone structure and strength are poorly understood. We investigated whether physically active adolescents had greater bone size, density, content, and estimated bone strength in young adulthood when compared to their peers who were inactive during adolescence. Peripheral quantitative computed tomography (pQCT) was used to measure the tibia and radius of 122 (73 females) participants (age mean ± SD, 29.3 ± 2.3 years) of the Saskatchewan Pediatric Bone Mineral Accrual Study (PBMAS). Total bone area (ToA), cortical density (CoD), cortical area (CoA), cortical content (CoC), and estimated bone strength in torsion (SSIp ) and muscle area (MuA) were measured at the diaphyses (66% tibia and 65% radius). Total density (ToD), trabecular density (TrD), trabecular content (TrC), and estimated bone strength in compression (BSIc ) were measured at the distal ends (4%). Participants were grouped by their adolescent physical activity (PA) levels (inactive, average, and active) based on mean PA Z-scores obtained from serial questionnaire assessments completed during adolescence. We compared adult bone outcomes across adolescent PA groups in each sex using analysis of covariance followed by post hoc pairwise comparisons with Bonferroni adjustments. When adjusted for adult height, MuA, and PA, adult males who were more physically active than their peers in adolescence had 13% greater adjusted torsional bone strength (SSIp , p < 0.05) and 10% greater adjusted ToA (p < 0.05) at the tibia diaphysis. Females who were more active in adolescence had 10% larger adjusted CoA (p < 0.05), 12% greater adjusted CoC (p < 0.05) at the tibia diaphysis, and 3% greater adjusted TrC (p < 0.05) at the distal tibia when compared to their inactive peers. Benefits to tibia bone size, content, and strength in those who were more active during adolescence seemed to persist into young adulthood, with greater ToA and SSIp in males, and greater CoA, CoC, and TrC in females.
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Affiliation(s)
- Rachel L Duckham
- College of Kinesiology, University of Saskatchewan, Saskatoon, Canada
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Johnston TE, Modlesky CM, Betz RR, Lauer RT. Muscle changes following cycling and/or electrical stimulation in pediatric spinal cord injury. Arch Phys Med Rehabil 2012; 92:1937-43. [PMID: 22133240 DOI: 10.1016/j.apmr.2011.06.031] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2011] [Revised: 06/04/2011] [Accepted: 06/27/2011] [Indexed: 11/28/2022]
Abstract
OBJECTIVE To determine the effect of cycling, electrical stimulation, or both, on thigh muscle volume and stimulated muscle strength in children with spinal cord injury (SCI). DESIGN Randomized controlled trial. SETTING Children's hospital specializing in pediatric SCI. PARTICIPANTS Children (N=30; ages, 5-13y) with chronic SCI. INTERVENTIONS Children were randomly assigned to 1 of 3 interventions: functional electrical stimulation cycling (FESC), passive cycling (PC), and noncycling, electrically stimulated exercise (ES). Each group exercised for 1 hour, 3 times per week for 6 months at home. MAIN OUTCOME MEASURES Preintervention and postintervention, children underwent magnetic resonance imaging to assess muscle volume, and electrically stimulated isometric muscle strength testing with the use of a computerized dynamometer. Data were analyzed via analyses of covariance (ANCOVA) with baseline measures as covariates. Within-group changes were assessed via paired t tests. RESULTS All 30 children completed the training. Muscle volume data were complete for 24 children (8 FESC, 8 PC, 8 ES) and stimulated strength data for 27 children (9 per group). Per ANCOVA, there were differences between groups (P<.05) for quadriceps muscle volume and stimulated strength, with the ES group having greater changes in volume and the FESC group having greater changes in strength. Within-group analyses showed increased quadriceps volume and strength for the FESC group and increased quadriceps volume for the ES group. CONCLUSIONS Children receiving either electrically stimulated exercise experienced changes in muscle size, stimulated strength, or both. These changes may decrease their risk of cardiovascular disease, insulin resistance, glucose intolerance, and type 2 diabetes. CLINICAL TRIALS REGISTRATION NUMBER NCT00245726.
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Affiliation(s)
- Therese E Johnston
- Department of Physical Therapy, University of the Sciences, Philadelphia, PA 19104, USA.
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Modlesky CM, Bajaj D, Kirby JT, Mulrooney BM, Rowe DA, Miller F. Sex differences in trabecular bone microarchitecture are not detected in pre and early pubertal children using magnetic resonance imaging. Bone 2011; 49:1067-72. [PMID: 21851868 PMCID: PMC3583530 DOI: 10.1016/j.bone.2011.07.041] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2011] [Revised: 07/11/2011] [Accepted: 07/28/2011] [Indexed: 10/17/2022]
Abstract
INTRODUCTION Sex differences in trabecular bone microarchitecture have been reported in adults and adolescents, but studies in children are lacking. The primary aim of this study was to determine if there are sex differences in magnetic resonance imaging (MRI)-based measures of trabecular bone microarchitecture at the distal femur of children. MATERIALS AND METHODS Pre and early pubertal boys (n=23) and girls (n=20) between the 5th and 95th percentiles for height, body mass and BMI were studied. Apparent trabecular bone volume to total volume (appBV/TV), trabecular number (appTb.N), trabecular thickness (appTb.Th), trabecular separation (appTb.Sp) and a composite measure of trabecular bone microarchitecture (TBMcom) were assessed at the lateral aspect of the distal femur using MRI. Areal bone mineral density (aBMD), bone mineral content (BMC) and bone area were assessed at the distal femur using dual-energy X-ray absorptiometry (DXA). Tanner staging was used to assess pubertal development. Physical activity was assessed using an accelerometry-based activity monitor. Calcium intake was assessed using diet records. RESULTS There were no sex differences in age, height, femur length, body mass, physical activity or calcium intake (all P>0.05). There were no sex differences in any MRI-based measure of trabecular bone microarchitecture. Consistent with the MRI-based measures, there were no differences in aBMD, BMC or bone area from DXA at the distal femur (P>0.05). appBV/TV, appTb.N, appTb.Th, appTb.Sp and TBMcom were also moderately to strongly related to aBMD (r=0.73, 0.63, 0.51, -0.74 and 0.61, respectively, p<0.001) and BMC (r=0.84, 0.63, 0.66, -0.80 and 0.77, respectively, P<0.001). CONCLUSIONS The findings suggest that there are no differences in measures of trabecular bone microarchitecture at the distal femur of pre and early pubertal boys and girls who are similar in size, physical activity and calcium intake. Future studies with larger sample sizes that cover all pubertal stages are needed to determine if sex differences in trabecular bone microarchitecture emerge at the distal femur and other weight bearing bone sites.
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Affiliation(s)
- Christopher M Modlesky
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE 19716, USA.
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15
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Bergmann P, Body JJ, Boonen S, Boutsen Y, Devogelaer JP, Goemaere S, Kaufman J, Reginster JY, Rozenberg S. Loading and skeletal development and maintenance. J Osteoporos 2010; 2011:786752. [PMID: 21209784 PMCID: PMC3010667 DOI: 10.4061/2011/786752] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2010] [Accepted: 11/06/2010] [Indexed: 12/12/2022] Open
Abstract
Mechanical loading is a major regulator of bone mass and geometry. The osteocytes network is considered the main sensor of loads, through the shear stress generated by strain induced fluid flow in the lacuno-canalicular system. Intracellular transduction implies several kinases and phosphorylation of the estrogen receptor. Several extra-cellular mediators, among which NO and prostaglandins are transducing the signal to the effector cells. Disuse results in osteocytes apoptosis and rapid imbalanced bone resorption, leading to severe osteoporosis. Exercising during growth increases peak bone mass, and could be beneficial with regards to osteoporosis later in life, but the gain could be lost if training is abandoned. Exercise programs in adults and seniors have barely significant effects on bone mass and geometry at least at short term. There are few data on a possible additive effect of exercise and drugs in osteoporosis treatment, but disuse could decrease drugs action. Exercise programs proposed for bone health are tedious and compliance is usually low. The most practical advice for patients is to walk a minimum of 30 to 60 minutes per day. Other exercises like swimming or cycling have less effect on bone, but could reduce fracture risk indirectly by maintaining muscle mass and force.
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Affiliation(s)
- P. Bergmann
- Department of Nuclear Medicine, Laboratory of Clinical Chemistry and Experimental Medicine, CHU Brugmann, Université Libre de Bruxelles, 4 Pl. Van Gehuchten, 1020 Brussels, Belgium,*P. Bergmann:
| | - J. J. Body
- Department of Medicine, CHU Brugmann, Université Libre de Bruxelles, 1020 Brussels, Belgium
| | - S. Boonen
- Division of Gerontology and Geriatrics, Center for Musculoskeletal Research, Department of Experimental Medicine, Catholic Leuven University, 3000 Leuven, Belgium
| | - Y. Boutsen
- Department of Rheumatology, Mont-Godinne University Hospital, Université Catholique de Louvain, 1200 Brussels, Belgium
| | - J. P. Devogelaer
- Rheumatology Unit, Saint-Luc University Hospital, Université Catholique de Louvain, 1200 Brussels, Belgium
| | - S. Goemaere
- Unit for Osteoporosis and Metabolic Bone Diseases, Ghent University Hospital, 9000 Ghent, Belgium
| | - J. Kaufman
- Unit for Osteoporosis and Metabolic Bone Diseases, Ghent University Hospital, 9000 Ghent, Belgium
| | - J. Y. Reginster
- Department of Public Health Sciences, University of Liège, 4000 Liège, Belgium
| | - S. Rozenberg
- Department of Gynaecology-Obstetrics, Free University of Brussels, 1090 Brussels, Belgium
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Janz KF, Letuchy EM, Eichenberger Gilmore JM, Burns TL, Torner JC, Willing MC, Levy SM. Early physical activity provides sustained bone health benefits later in childhood. Med Sci Sports Exerc 2010; 42:1072-8. [PMID: 19997029 PMCID: PMC2874089 DOI: 10.1249/mss.0b013e3181c619b2] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE This study examined the potential effect of early childhood moderate and vigorous physical activity (MVPA) on later bone health. METHODS Three hundred and thirty-three children, participating in the Iowa Bone Development Study, were studied at ages 5, 8, and 11 yr. MVPA (min x d(-1)) was measured using an accelerometry-based physical activity monitor. Bone mineral content (BMC; g) of the whole body, lumbar spine, and hip was measured using dual-energy x-ray absorptiometry. Mixed regression models were used to test whether MVPA at age 5 yr had an effect on BMC at ages 8 and 11 yr after adjustment for concurrent height, weight, age, maturity, and MVPA. The analysis was repeated to control for bone outcomes at age 5 yr. Mixed-model least-squares mean values at the person level of covariates for age group were used to compare the BMC at ages 8 and 11 yr of children in the highest and lowest quartiles of MVPA at age 5 yr. RESULTS For boys and girls, MVPA at age 5 yr predicted BMC adjusted for concurrent height, weight, age, maturity, and MVPA at ages 8 and 11 yr (P < 0.05). When the analysis was repeated to also control for BMC at age 5 yr, the effect of MVPA at age 5 yr was significant for boys but not for girls. Boys and girls in the highest quartile of MVPA at age 5 yr had 4%-14% more BMC at ages 8 and 11 yr than those in the lowest quartile of MVPA at age 5 yr (P < 0.05). CONCLUSIONS These results provide support for the benefits of early MVPA on sustained bone health during childhood especially for boys. Results indicate the importance of increasing MVPA as a strategy to improve BMC later in childhood.
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Affiliation(s)
- Kathleen F Janz
- Department of Health and Sport Studies, The University of Iowa, Iowa City, IA 52242, USA.
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17
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de Matos O, Lopes da Silva DJ, Martinez de Oliveira J, Castelo-Branco C. Effect of specific exercise training on bone mineral density in women with postmenopausal osteopenia or osteoporosis. Gynecol Endocrinol 2009; 25:616-20. [PMID: 19533480 DOI: 10.1080/09513590903015593] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
AIM To analyse the effect of a specific program of weight training exercise with closed kinetic chain in bone mineral density in postmenopausal women with osteopenia or osteoporosis. METHODS A total of 59 postmenopausal women with osteoporosis or osteopenia were included in this prospective study. Subjects were divided into two groups: the study group (SG, n = 30; 57.5 + or - 5.1 years) and the control group (CG, n = 29; 56.6 + or - 4.6 years). In the study group was applied a weight exercise protocol (longitudinal forces in closed kinetic chain) during 12 months, whereas in the control group no weight exercise protocol was applied. Bone mineral density at the lumbar spine and hip was assessed at baseline and at the end of follow-up by dual energy X-ray absorptiometry. RESULTS. Although no significant intragroup differences were found, patients in SG showed a 1.17% increase in the lumbar spine whereas in CG a 2.26% decrease in bone density was detected. CONCLUSION This protocol of weight training exercise did not significantly improve bone mineral density in postmenopausal women with osteopenia or osteoporosis, but in comparison to the control group, the results showed the importance of practising the specific exercise program for maintenance of bone health in postmenopausal women.
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Baxter-Jones ADG, Kontulainen SA, Faulkner RA, Bailey DA. A longitudinal study of the relationship of physical activity to bone mineral accrual from adolescence to young adulthood. Bone 2008; 43:1101-7. [PMID: 18725335 DOI: 10.1016/j.bone.2008.07.245] [Citation(s) in RCA: 116] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2008] [Revised: 07/16/2008] [Accepted: 07/30/2008] [Indexed: 11/23/2022]
Abstract
Physical activity in adolescence is beneficial for increasing bone mineral accrual; however, it's unclear whether these benefits persist into adulthood. This prospective study investigated whether physically active adolescents maintained their higher bone mineral content (BMC) into the third decade of life when compared to their less active peers. Data were from 154 subjects (82 females and 72 males) who participated in the University of Saskatchewan's Pediatric Bone Mineral Accrual Study (1991-1997), entry age 8 to 15 years. Participants returned for follow-up as young adults (2002-2006), follow-up age 23 to 30 years. Dual energy X-ray absorptiometry was used to measure BMC of total body (TB), lumbar spine (LS), total hip (TH) and femoral neck (FN) annually from 1991 to 1997 and from 2002 to 2006. Peak height velocity (PHV) was determined for each child as a measure of maturity. Age and gender-specific activity Z-scores were calculated for each participant based on the mean physical activity scores obtained from bi-annual questionnaire data during childhood and adolescence. Subjects were ranked into three adolescent activity groups: active, average and inactive (top, middle two, and bottom quartiles, respectively). Analysis of covariance (ANCOVA) was used to compare adjusted TB, LS, TH and FN BMC across the three adolescent activity groups at 1 year post PHV and in young adulthood. When compared to the inactive group, active males had 8% greater adjusted BMC at the TB, 13% at the LS and 11% at the TH (p<0.05) in adolescence. Active females also had 8% and 15% more adjusted BMC (p<0.05) at the TB and LS, respectively, during adolescence. In young adulthood the male and female adolescent active groups were still significantly more active than their peers (p>0.05). It was found that active adolescent males had 8-10% more adjusted BMC at the TB, TH and FN (p<0.05) in young adulthood and that active adolescent females had 9% and 10% more adjusted BMC at the TH and FN. These results suggest that the skeletal benefits of physically activity in adolescents are maintained into young adulthood.
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Affiliation(s)
- Adam D G Baxter-Jones
- College of Kinesiology, 87 Campus Drive, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
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Honda A, Sogo N, Nagasawa S, Kato T, Umemura Y. Bones benefits gained by jump training are preserved after detraining in young and adult rats. J Appl Physiol (1985) 2008; 105:849-53. [PMID: 18599679 DOI: 10.1152/japplphysiol.00902.2007] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We investigated the osteogenic responses to jump training and subsequent detraining in young and adult male rats to test the following hypotheses: 1) jump training has skeletal benefits; 2) these skeletal benefits are preserved with subsequent detraining throughout bone morphometric changes; and 3) there are no differences between young and adult rats during detraining in terms of the maintenance of exercise-induced changes. Twelve-week-old (young) and 44-wk-old (adult) rats were divided into the following four groups: young-sedentary, young-exercised, adult-sedentary, and adult-exercised. The exercised groups performed jump training (height = 40 cm, 10 jumps/day, 5 days/wk) for 8 wk followed by 24 wk of being sedentary. Tibial bone mineral content and bone mineral density in vivo significantly increased with jump training, and the effects were maintained after detraining in both the young and adult exercised groups, although the benefits of training became somewhat diminished. After 24 wk of detraining, the beneficial effects of training on bone mass and strength were preserved and associated with morphometric changes, such as periosteal perimeter, cortical area, and moment of inertia. There were no significant age-exercise interactions in such parameters, except for the periosteal perimeter. These results suggest that there are few differences in bone accommodation and maintenance by training and detraining between young and adult rats.
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Affiliation(s)
- Akiko Honda
- School of Health and Sport Sciences, Chukyo Univ., 101 Tokodachi, Kaizu-cho, Toyota, Aichi, 470-0393 Japan.
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20
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Modlesky CM, Majumdar S, Dudley GA. Trabecular bone microarchitecture in female collegiate gymnasts. Osteoporos Int 2008; 19:1011-8. [PMID: 18074110 DOI: 10.1007/s00198-007-0522-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2007] [Accepted: 10/01/2007] [Indexed: 10/22/2022]
Abstract
UNLABELLED Using high-resolution magnetic resonance imaging, we observed more developed trabecular bone microarchitecture in the proximal tibia of female collegiate gymnasts vs. matched controls. This suggests that high-load physical activity may have a positive effect on the trabecular microarchitecture in weight-bearing bone. INTRODUCTION Participation in physical activities that overload the skeleton, such as artistic gymnastics, is associated with increased areal bone mineral density (aBMD); however, the status of trabecular microarchitecture in the weight-bearing bone of gymnasts is unknown. METHODS Eight female collegiate artistic gymnasts and eight controls matched for age, height, body mass, gender and race were recruited for the study. Apparent trabecular bone volume to total volume (appBV/TV), trabecular number (appTb.N), thickness (appTb.Th) and trabecular separation (appTb.Sp) were determined using high resolution magnetic resonance imaging. Areal bone mineral density, bone mineral content (BMC) and bone area in the proximal tibia were determined using dual-energy X-ray absorptiometry. Group differences were determined using t-tests. The magnitude of group differences was expressed using Cohen's d (d). RESULTS Gymnasts had higher appBV/TV (13.6%, d = 1.22) and appTb.N (8.4%, d = 1.45), and lower appTb.Sp (13.7%, d = 1.33) than controls (p < 0.05). Gymnasts had higher aBMD and BMC in the proximal tibia, although the differences were smaller in magnitude (d = 0.75 and 0.74, respectively) and not statistically significant (p > 0.05). CONCLUSION The findings suggest that high-load physical activity, such as performed during gymnastics training, may enhance the trabecular microarchitecture of weight-bearing bone.
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Affiliation(s)
- C M Modlesky
- Department of Health, Nutrition and Exercise Sciences, University of Delaware, Newark, DE, 19716, USA.
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21
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Poliachik SL, Threet D, Srinivasan S, Gross TS. 32 wk old C3H/HeJ mice actively respond to mechanical loading. Bone 2008; 42:653-9. [PMID: 18280231 PMCID: PMC2366046 DOI: 10.1016/j.bone.2007.12.222] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2007] [Revised: 12/19/2007] [Accepted: 12/27/2007] [Indexed: 10/22/2022]
Abstract
Numerous studies indicate that C3H/HeJ (C3H) mice are mildly responsive to mechanical loading compared to C57BL/6J (C57) mice. Guided by data indicating high baseline periosteal osteoblast activity in 16 wk C3H mice, we speculated that simply allowing the C3H mice to age until basal periosteal bone formation was equivalent to that of 16 wk C57 mice would restore mechanoresponsiveness in C3H mice. We tested this hypothesis by subjecting the right tibiae of 32 wk old C3H mice and 16 wk old C57 mice to low magnitude rest-inserted loading (peak strain: 1235 mu epsilon) and then exposing the right tibiae of 32 wk C3H mice to low (1085 mu epsilon) or moderate (1875 mu epsilon) magnitude cyclic loading. The osteoblastic response to loading on the endocortical and periosteal surfaces was evaluated via dynamic histomorphometry. At 32 wk of age, C3H mice responded to low magnitude rest-inserted loading with significantly elevated periosteal mineralizing surface, mineral apposition rate and bone formation compared to unloaded contralateral bones. Surprisingly, the periosteal bone formation induced by low magnitude rest-inserted loading in C3H mice exceeded that induced in 16 wk C57 mice. At 32 wk of age, C3H mice also demonstrated an elevated response to increased magnitudes of cyclic loading. We conclude that a high level of basal osteoblast function in 16 wk C3H mice appears to overwhelm the ability of the tissue to respond to an otherwise anabolic mechanical loading stimulus. However, when basal surface osteoblast activity is equivalent to that of 16 wk C57 mice, C3H mice demonstrate a clear ability to respond to either rest-inserted or cyclic loading.
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Affiliation(s)
- Sandra L Poliachik
- Department of Orthopaedics and Sports Medicine, University of Washington, Seattle, WA, 98104, USA.
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22
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Modlesky CM, Subramanian P, Miller F. Underdeveloped trabecular bone microarchitecture is detected in children with cerebral palsy using high-resolution magnetic resonance imaging. Osteoporos Int 2008; 19:169-76. [PMID: 17962918 DOI: 10.1007/s00198-007-0433-x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2007] [Accepted: 08/31/2007] [Indexed: 10/22/2022]
Abstract
UNLABELLED Using high resolution magnetic resonance imaging, we detected severely underdeveloped trabecular bone microarchitecture in the distal femur of children with cerebral palsy who can not ambulate independently vs. typically developing controls. Furthermore, very good short-term reliability of trabecular bone microarchitecture measurements was observed in both groups of children. INTRODUCTION Severe forms of cerebral palsy (CP) are associated with very low areal bone mineral density and a very high incidence of fracture in the distal femur; however, the state of trabecular bone microarchitecture has not been evaluated. Furthermore, the short-term reliability of trabecular bone microarchitecture assessment in children using high-resolution magnetic resonance imaging (MRI) has not been determined. METHODS Apparent bone volume to total volume (appBV/TV), trabecular number, (appTb.N), trabecular thickness (appTb.Th) and trabecular separation (appTb.Sp) were determined in the distal femur of non-ambulatory children with CP and typically developing children using MRI. RESULTS Children with CP had a 30% lower appBV/TV, a 21% lower appTb.N, a 12% lower appTb.Th and a 48% higher appTb.Sp in the distal femur than controls (n = 10/group; P < 0.001). The short-term reliability of the trabecular bone microarchitecture measures was very good, with coefficients of variation ranging from 2.0 to 3.0% in children with CP (n = 6) and 1.8 to 3.5% in control children (n = 6). CONCLUSIONS Underdeveloped trabecular bone microarchitecture can be detected in the distal femur of children with CP who can not ambulate independently using high-resolution MRI. Furthermore, MRI can be used to assess trabecular bone microarchitecture in children with a high degree of reliability.
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Affiliation(s)
- C M Modlesky
- Department of Health, Nutrition and Exercise Sciences, University of Delaware, Newark, DE 19716, USA.
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Umemura Y, Nagasawa S, Sogo N, Honda A. Effects of jump training on bone are preserved after detraining, regardless of estrogen secretion state in rats. J Appl Physiol (1985) 2008; 104:1116-20. [PMID: 18218903 DOI: 10.1152/japplphysiol.00937.2007] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We investigated whether the effects of jump training on bone are preserved after a detraining period in female normal and estrogen-deficient rats. Forty-four 11-wk-old Wistar rats were divided into the following four groups: sham sedentary (n = 12), sham exercised (n = 11), ovariectomized sedentary (n = 10), and ovariectomized exercised (n = 11). An 8-wk exercise period was introduced in which the rats in the exercised groups were jumped 10 times/day, 5 days/wk. This was followed by 24 wk of detraining. At the end of the exercise period, the jump training significantly increased the bone mineral content of the tibia (P < 0.001), measured by dual-energy X-ray absorptiometry. After the detraining period, the bone mineral content (P < 0.01), strength (P < 0.001), and cross-sectional widths (P < 0.001) of the tibia in the exercised groups were still greater than in the sedentary groups, without significant surgery-exercise interactions, although bone stiffness in the fracture test (P < 0.05) and bone area in the center-proximal region, as measured by dual-energy X-ray absorptiometry (P < 0.05), showed significant surgery-exercise interactions. These findings suggest that the exercise effect on bone strength is preserved, accompanied by cross-sectional morphological changes, even under estrogen deficiency.
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Affiliation(s)
- Yoshihisa Umemura
- Laboratory for Exercise Physiology and Biomechanics, School of Health and Sport Sciences, Chukyo Univ., 101 Tokodachi, Kaizu-cho, Toyota 470-0393, Japan.
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Janz KF, Gilmore JME, Levy SM, Letuchy EM, Burns TL, Beck TJ. Physical activity and femoral neck bone strength during childhood: the Iowa Bone Development Study. Bone 2007; 41:216-22. [PMID: 17560839 PMCID: PMC2002473 DOI: 10.1016/j.bone.2007.05.001] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2007] [Revised: 05/01/2007] [Accepted: 05/02/2007] [Indexed: 11/26/2022]
Abstract
Structural adaptations of bone to changing mechanical loads have recently been documented during adolescence. However, little is known about how bone adapts structurally during the earlier years. Using a longitudinal observational design spanning 6 years of growth (age range 4 to 12 years), we investigated associations between everyday physical activity and hip geometry in a cohort of healthy Midwestern children (n=468). Femoral neck (FN) cross sectional area (CSA, cm(2)) and FN section modulus (Z, cm(3)) were used to describe hip geometry. CSA and Z, indices of axial and bending strength, were assessed using dual-energy X-ray absorptiometry (DXA) scans and the hip structure analysis (HSA) program. Moderate and vigorous physical activity (MVPA) was assessed using accelerometry-based activity monitors and calculated as the number of minutes > or =3000 accelerometry movement counts. Data were analyzed using multilevel (random- and fixed-effects) regression models with adjustment for age (year), height (cm), and weight (kg) or lean mass (kg). For boys and girls, MVPA was a positive independent predictor of CSA and Z (p<0.05). On average, children who participated in 40 min of MVPA per day would be expected to have 3% to 5% greater CSA and Z than peers participating in 10 min of MVPA per day. Ten-minute increases in daily MVPA had similar effects on CSA in girls and Z in boys as did each additional 1 kg of body weight. When lean mass was substituted for weight, MVPA continued to be a positive independent predictor of CSA and Z for boys, but not girls. This study demonstrates that everyday amounts of physical activity in children are associated with indices of FN bone strength during childhood. Differences in lean mass mediate associations between physical activity and hip geometry in girls, but only somewhat in boys. These results suggest that physical activity is an important contributor to bone strength prior to adolescence and that increasing levels of physical activity during childhood are likely to enhance optimal bone strength.
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Affiliation(s)
- Kathleen F Janz
- Department of Health and Sport Studies, The University of Iowa, Iowa City, Iowa, USA.
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Nickols-Richardson SM, Miller LE, Wootten DF, Ramp WK, Herbert WG. Concentric and eccentric isokinetic resistance training similarly increases muscular strength, fat-free soft tissue mass, and specific bone mineral measurements in young women. Osteoporos Int 2007; 18:789-96. [PMID: 17264975 DOI: 10.1007/s00198-006-0305-9] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2006] [Accepted: 11/22/2006] [Indexed: 10/23/2022]
Abstract
UNLABELLED Women participated in 5 months of unilateral concentric (n = 37) or eccentric (n = 33) isokinetic resistance training of the legs and arms. Limb muscular strength increased as did total body, leg, and arm fat-free soft tissue mass, total body BMC, hip BMD, and forearm BMC and BMD. Isokinetic training benefits bone mineral acquisition. INTRODUCTION AND HYPOTHESIS Isokinetic resistance training (IRT) is osteogenic; however, it is not known if concentric or eccentric modalities of IRT produce differential effects on bone. We tested our hypothesis that high-load eccentric versus concentric mode of IRT would produce greater increases in muscular strength, fat-free soft tissue mass (FFSTM), bone mineral density (BMD) and content (BMC) in trained legs and arms. METHODS Participants were randomized to 5 months of concentric (n = 37) or eccentric (n = 33) training. The non-dominant leg and arm were used during training; dominant limbs served as controls. Muscular strength was measured with an isokinetic dynamometer; body composition was measured by dual-energy X-ray absorptiometry. RESULTS Muscular strength of the concentrically and eccentrically trained leg (18.6%; 28.9%) and arm (12.5%; 24.6%) significantly increased with training. Gains in total body (TB) BMC (p < 0.05) and, in the trained limbs, total proximal femur BMD (p < 0.05) and total forearm BMD (p < 0.05) and BMC (p < 0.05) occurred in both groups. FFSTM increased for the TB and trained leg and arm (all p < 0.001) in both modes. CONCLUSION Regardless of the mode, high-intensity, slow-velocity IRT increases muscular strength and FFSTM of trained limbs and imparts benefits to TB BMC and site-specific BMD and BMC in young women.
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Affiliation(s)
- S M Nickols-Richardson
- Department of Nutritional Sciences, The Pennsylvania State University, University Park, PA 16802, USA.
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Ducher G, Blimkie CJ. Adaptations architecturales du tissu osseux en réponse à l'exercice physique : intérêts et limites des méthodes non invasives utilisées chez l'homme. Sci Sports 2006. [DOI: 10.1016/j.scispo.2006.08.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Laing EM, Wilson AR, Modlesky CM, O'Connor PJ, Hall DB, Lewis RD. Initial years of recreational artistic gymnastics training improves lumbar spine bone mineral accrual in 4- to 8-year-old females. J Bone Miner Res 2005; 20:509-19. [PMID: 15746997 DOI: 10.1359/jbmr.041127] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2004] [Revised: 08/14/2004] [Accepted: 09/28/2004] [Indexed: 11/18/2022]
Abstract
UNLABELLED Gymnasts' bone mineral characteristics are generally not known before starting their sport. Prepubertal females who enrolled in beginning artistic gymnastics (n = 65) had lower bone mineral than controls (n = 78). However, 2 years of gymnastics participation versus no participation led to a significantly greater accrual of forearm bone area and lumbar spine areal BMD. INTRODUCTION The skeletal response to exercise in children compared with adults is heightened because of the high bone turnover rate and the ability of bone to change its size and shape. Whereas child gymnasts generally have greater rates of bone mineral accrual compared with nongymnasts, it is unknown if some of these skeletal advantages are present before the onset of training or are caused entirely by training. MATERIALS AND METHODS Changes in bone area (BA; cm2), BMC (g), and areal BMD (aBMD; g/cm2) over 24 months were examined in prepubertal females, 4-8 years of age, who selected to perform recreational gymnastics (GYM; n = 65), nongymnastic activities, or no organized activity (CON; n = 78). Participants had essentially no lifetime history of organized athletic participation (< 12 weeks). Pubertal maturation was assessed annually by a physician. Total body, lumbar spine, total proximal femur, and forearm BA, BMC, and aBMD were measured every 6 months using DXA (Hologic QDR-1000W). Independent samples t-tests determined baseline group differences. Nonlinear mixed effects models were used to model 24-month changes in bone data. In subset analyses, high-level gymnasts advancing to competition (HLG; n = 9) were compared with low-level nonadvancing gymnasts (LLG; n = 56). RESULTS At baseline, GYM were shorter, lighter, and had lower BA, BMC, and aBMD compared with CON (p < 0.05), whereas HLG did not differ significantly in these measurements compared with LLG (p > 0.05). Controlling for differences in race, baseline measures of body mass, height, and calcium intake, and change in breast development beyond stage II at 24 months, GYM had greater long-term (asymptotic) mean responses for total body aBMD and forearm BMC (p < 0.04) and greater rates of increase in the mean responses of lumbar spine aBMD and forearm BA compared with CON over 24 months. Over time, forearm BA increased to a greater extent in HLG compared with LLG (p < 0.01). CONCLUSIONS Females participating in recreational gymnastics initiated during childhood have enhanced bone mineral gains at the total body, lumbar spine, and forearm over 24 months. Higher-level training promotes additional gains in forearm BA.
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Affiliation(s)
- Emma M Laing
- Department of Foods and Nutrition, The University of Georgia, Athens, Georgia 30602, USA
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Modlesky CM, Slade JM, Bickel CS, Meyer RA, Dudley GA. Deteriorated geometric structure and strength of the midfemur in men with complete spinal cord injury. Bone 2005; 36:331-9. [PMID: 15780960 DOI: 10.1016/j.bone.2004.10.012] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2003] [Revised: 10/14/2004] [Accepted: 10/20/2004] [Indexed: 11/28/2022]
Abstract
Spinal cord injury (SCI) results in a dramatic loss of bone mineral and a marked increase in fracture incidence in the femur; however, its effect on the femur's geometric structure and strength is poorly studied. The primary purpose of the present study was to assess the geometric structure, composition, and strength of the midfemur in men with long-term (>2 years), complete SCI (C6-L1 level; n=7) relative to men without SCI (n=8). T1-weighted axial images of the thigh were collected on a GE 1.5-T magnetic resonance imager and geometric, structure, composition, and strength measurements of the midfemur and skeletal muscle volume of the midthigh were determined. Areal bone mineral density (aBMD), bone mineral content (BMC), and bone area of the midthird of the femur and arms were determined using dual-energy X-ray absorptiometry. There were no differences in age, height, weight, femur length, arm BMC, arm aBMD, or arm bone area between the SCI group and controls. While the volume of the midfemur was not different in the two groups, the medullary cavity had 53% more volume and was 21-25% wider in the SCI group (P<0.05). In contrast, the cortical wall in the SCI group had a 24% lower volume and was 27-47% thinner (P<0.05). The cortical wall was particularly thin in the posterior section of the bone. The SCI group also had lower BMC and aBMD in the midfemur (21% and 25%, respectively, P<0.05). Calculated cross-sectional moment of inertia (CSMI), section modulus (Z), and polar moment of inertia (J) were lower in the SCI group (13-19%, P<0.05). A higher ratio of cortical bone volume to muscle volume and BMC to muscle volume in the SCI group (P<0.05) suggests that there was a greater loss of muscle than cortical bone after SCI; however, muscle volume was strongly correlated with cortical bone volume and BMC in the SCI and control groups (r=0.71 to 0.90, P<0.05). Muscle volume was also moderately to strongly correlated with CSMI and Z in the anterior-posterior direction and J. Muscle volume was weakly correlated or not correlated with bone strength measures in the control group (P>0.05). These findings suggest that after SCI, the midfemur erodes on the endosteal surface, resulting in a decreased resistance to bending and torsion. Although midthigh muscle volume appears to decline to a greater degree than midfemur cortical bone volume and BMC, their relationships remain strong.
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Affiliation(s)
- Christopher M Modlesky
- Department of Health, Nutrition and Exercise Sciences, University of Delaware, Newark, DE 19716, USA.
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Janz KF, Burns TL, Levy SM, Torner JC, Willing MC, Beck TJ, Gilmore JM, Marshall TA. Everyday Activity Predicts Bone Geometry in Children: The Iowa Bone Development Study. Med Sci Sports Exerc 2004; 36:1124-31. [PMID: 15235315 DOI: 10.1249/01.mss.0000132275.65378.9d] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE Bone adapts to changing mechanical loads by altering the structure appropriately. These adaptations should be evident in the bone cross-sectional area (CSA) and section modulus (Z), indices of axial and bending strength, respectively. In this cross-sectional study, we investigated associations between physical activity, CSA, and Z in 467 young children (mean age 5.2 yr). We also examined whether lean tissue mass, which is predominantly muscle, mediates the relationship between physical activity and bone structural measures. METHODS Physical activity was assessed using accelerometry and questionnaire. Proximal femur measures of the neck, intertrochanteric, and shaft CSA (cm) and Z (cm) were derived from dual-energy x-ray absorptiometry (DXA) scans using the Hip Structure Analysis program. Total body lean mass (kg) was also measured using DXA. RESULTS Boys were more physically active than girls. Boys also had greater CSA, Z, and lean mass than girls. At each region, time spent in vigorous activity was positively and consistently associated with CSA and Z in boys and girls (r = 0.19 to 0.32). After adjustment for age, body mass, and height, vigorous activity explained, on average, 6.9% of the variability in CSA and Z. With additional adjustment for lean mass, vigorous activity explained 3.7% of the remaining variability in CSA and Z. CONCLUSION This study demonstrates that everyday amounts of physical activity in healthy, normal children are associated with bone geometry and that differences in lean mass explain some, but not all, of this association. This suggests that, even in young, nonathletic children, bone may adapt to physical activity by structurally remodeling.
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Affiliation(s)
- Kathleen F Janz
- Health and Sport Studies, The University of Iowa, Iowa City, IA 52242, USA.
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Female Athlete Issues for the Team Physician: A Consensus StatementFemale Athlete Issues for the Team Physician: A Consensus Statement. Med Sci Sports Exerc 2003; 35:1785-93. [PMID: 14523321 DOI: 10.1249/01.mss.0000089353.24886.bb] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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