Motor Competence in Early Childhood Is Positively Associated with Bone Strength in Late Adolescence

The onset of walking in early childhood results in exposure of the lower limb to substantial forces from weight bearing activity that ultimately contribute to adult bone strength. Relationships between gross motor score (GMS), at 18 months and bone outcomes measured at age 17 years were examined in 2327 participants in the Avon Longitudinal Study of Parents and Children (ALSPAC). Higher GMS indicated greater motor competence in weight‐bearing activities. Total hip bone mineral density (BMD) and hip cross‐sectional moment of inertia (CSMI) were assessed from dual‐energy X‐ray absorptiometry (DXA). Bone measures including cortical bone mineral content (BMC), periosteal circumference (PC), cortical thickness (CT), cortical bone area (CBA), cortical BMD (BMD(C)) and cross‐sectional moment of inertia (CSMI) were assessed by peripheral quantitative computed tomography (pQCT) at 50% distal‐proximal length. Before adjustment, GMS was associated with hip BMD, CSMI, and tibia BMC, PC, CT, CBA and CSMI (all p < 0.001) but not BMD(C) (p > 0.25). Strongest associations (standardized regression coefficients with 95% CI) were between GMS and hip BMD (0.086; 95% CI, 0.067 to 0.105) and tibia BMC (0.105; 95% CI, 0.089 to 0.121). With the exception of hip BMD, larger regression coefficients were observed in males (gender interactions all p < 0.05). Adjustment for lean mass resulted in substantial attenuation of regression coefficients, suggesting associations between impaired motor competence and subsequent bone development are partly mediated by alterations in body composition. In conclusion, impaired motor competence in childhood is associated with lower adolescent bone strength, and may represent a risk factor for subsequent osteoporosis. © 2015 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research (ASBMR)

Associations between long-term exercise participation and lower limb joint and whole-bone geometry in young and older adults

Introduction: Features of lower limb bone geometry are associated with movement kinematics and clinical outcomes including fractures and osteoarthritis. Therefore, it is important to identify their determinants. Lower limb geometry changes dramatically during development, partly due to adaptation to the forces experienced during physical activity. However, the effects of adulthood physical activity on lower limb geometry, and subsequent associations with muscle function are relatively unexplored. Methods: 43 adult males were recruited; 10 young (20–35 years) trained i.e., regional to world-class athletes, 12 young sedentary, 10 older (60–75 years) trained and 11 older sedentary. Skeletal hip and lower limb geometry including acetabular coverage and version angle, total and regional femoral torsion, femoral and tibial lateral and frontal bowing, and frontal plane lower limb alignment were assessed using magnetic resonance imaging. Muscle function was assessed recording peak power and force of jumping and hopping using mechanography. Associations between age, training status and geometry were assessed using multiple linear regression, whilst associations between geometry and muscle function were assessed by linear mixed effects models with adjustment for age and training. Results: Trained individuals had 2° (95% CI:0.6°–3.8°; p = 0.009) higher femoral frontal bowing and older individuals had 2.2° (95% CI:0.8°–3.7°; p = 0.005) greater lateral bowing. An age-by-training interaction indicated 4° (95% CI:1.4°–7.1°; p = 0.005) greater acetabular version angle in younger trained individuals only. Lower limb geometry was not associated with muscle function (p > 0.05). Discussion: The ability to alter skeletal geometry via exercise in adulthood appears limited, especially in epiphyseal regions. Furthermore, lower limb geometry does not appear to be associated with muscle function

Pregnancy and lactation, a challenge for the skeleton

In this review we discuss skeletal adaptations to the demanding situation of pregnancy and lactation. Calcium demands are increased during pregnancy and lactation, and this is effectuated by a complex series of hormonal changes. The changes in bone structure at the tissue and whole bone level observed during pregnancy and lactation appear to largely recover over time. The magnitude of the changes observed during lactation may relate to the volume and duration of breastfeeding and return to regular menses. Studies examining long-term consequences of pregnancy and lactation suggest that there are small, site-specific benefits to bone density, and that bone geometry may also be affected. Pregnancy- and lactation-induced osteoporosis (PLO) is a rare disease for which the pathophysiological mechanism is as yet incompletely known; here we discuss and speculate on the possible roles of genetics, oxytocin, sympathetic tone and bone marrow fat. Finally, we discuss fracture healing during pregnancy and lactation and the effects of estrogen on this process

Vertebral fractures and daily pain are associated with lower physical activity in postmenopausal women with back pain

Around 12% of women have vertebral fractures (VFs), and many of these individuals also have back pain which limits physical activity (PA). PA is important for health, but little is known about how VFs affect PA, and if so how this compares with individuals with back pain due to other causes. Therefore, we recruited 37 postmenopausal women from primary care with back pain, in whom the presence or absence of VFs was ascertained by spine radiographs. To provide an objective PA measure, vertical accelerations were recorded at 100 Hz for 7 days using a hip-worn GT3X+ accelerometer (Actigraph, USA). The number of low (0.5g-2g) was recorded. Participants also recorded their average back pain each day using a 10-point Likert scale. Linear mixed-effects models were used to assess group differences (fracture/nofracture cases) in low, medium and high-impact PA, and associations between daily pain and different PA impact levels. Daily PA and pain data had non-normal distributions and were log transformed. 12 women were found to have previously sustained VFs. These participants had lower levels of lowimpact PA (regression coefficient -0.64, 95%CI -1.03 to -0.25, P=0.002) but not medium or highimpact PA (both P>0.2). Across all participants, higher daily pain was associated with lower highimpact PA levels (-0.08, 95%CI -0.14 to -0.02, P=0.014) and weakly with medium–impact PA (-0.1, 95%CI -0.22 to 0.02, P=0.081) but not low-impact PA (P=0.25). These results suggest that VFs and daily pain are associated with lower levels of low and high-impact PA respectively, shown previously to differentially affect components of health. Low levels of low impact PA in women with VFs may impair weight control in these women. In contrast, reduced PA, in particular high-impact PA, in women with higher daily pain levels may increase the risk of sarcopenia and osteoporosis

Associations between long-term exercise participation and lower limb joint and whole-bone geometry in young and older adults

Introduction: Features of lower limb bone geometry are associated with movement kinematics and clinical outcomes including fractures and osteoarthritis. Therefore, it is important to identify their determinants. Lower limb geometry changes dramatically during development, partly due to adaptation to the forces experienced during physical activity. However, the effects of adulthood physical activity on lower limb geometry, and subsequent associations with muscle function are relatively unexplored.Methods: 43 adult males were recruited; 10 young (20–35 years) trained i.e., regional to world-class athletes, 12 young sedentary, 10 older (60–75 years) trained and 11 older sedentary. Skeletal hip and lower limb geometry including acetabular coverage and version angle, total and regional femoral torsion, femoral and tibial lateral and frontal bowing, and frontal plane lower limb alignment were assessed using magnetic resonance imaging. Muscle function was assessed recording peak power and force of jumping and hopping using mechanography. Associations between age, training status and geometry were assessed using multiple linear regression, whilst associations between geometry and muscle function were assessed by linear mixed effects models with adjustment for age and training.Results: Trained individuals had 2° (95% CI:0.6°–3.8°; p = 0.009) higher femoral frontal bowing and older individuals had 2.2° (95% CI:0.8°–3.7°; p = 0.005) greater lateral bowing. An age-by-training interaction indicated 4° (95% CI:1.4°–7.1°; p = 0.005) greater acetabular version angle in younger trained individuals only. Lower limb geometry was not associated with muscle function (p &gt; 0.05).Discussion: The ability to alter skeletal geometry via exercise in adulthood appears limited, especially in epiphyseal regions. Furthermore, lower limb geometry does not appear to be associated with muscle function

Original Dynamometric and Tomographic evidence of site-specific muscle effects on bone structure. Towards a wider scope on the bone Mechanostat concept

Para analizar el impacto directo de la musculatura sobre la estructura ósea se determinaronel área (CtA), la densidad mineral ósea volumétrica (vDMOc) y los momentos de inerciacorticales para flexión anteroposterior y lateral(MIap, MIlat) ajustados a CtA, y las relacionesentre MI y vDMOc (de ʻdistribución/calidadʼ, d/c,que describen la eficiencia de la optimizaciónbiomecánica del diseño cortical por el mecanostato) en 18 cortes seriados a lo largo detodo el peroné del lado hábil (pQCT), y lafuerza de salto y de rotación externa del pie(dinamometría computarizada) de 22 hombressanos de 18 a 33 años entrenados en fútbolcompetitivo por más de 4 años, y de 9 controlesetarios no entrenados. Los entrenados tuvieronvalores más altos de MI en función de la fuerzade rotación del pie (no de salto), con un ajustehomogéneo para MIap pero variable (más pobredistalmente y más alto proximalmente, en laregión de inserción de los peroneos) para MIlat,coincidiendo este último con pobres ajustes delas relaciones d/c (efecto arquitectónico independiente de la rigidez del tejido). Esto evidencia la influencia directa de la tracción de lamusculatura peronea sobre la estructura cortical proximal subyacente del hueso y tambiénsugiere que el mecanostato procedería, en estecaso, fuera de su conocida concepción comomecanismo regulatorio de la resistencia ósea.To analyze the direct impact of muscle contractions on the structure of bones, we determined the cortical cross-sectional area (CtA), volumetric mineral density (vBMDc) and the CtA-adjusted moments of inertia for anterior-posterior and lateral bending (MIap, MIlat), and the ‘distribution/quality’ (d/c) relationships between MIs and vBMDc (which describe the efficiency of the biomechanical optimization of cortical design by bone mechanostat) in 18 serial scans taken throughout the fibula of the dominant side (pQCT), and the jump and the foot-lateral-rotation forces (computed dynamometry) of 22 healthy men aged 18-33 years, who had been trained in competitive soccer for more than 4 years, and of 9 untrained, age-matched controls. Trained individuals showed higher MI values as a function of the rotative force of the foot (not the jumping force). The adjustment of these relationships was homogeneous for MIap throughout the bone, but variable (poorer distally and higher proximally, at the insertion area of peroneus muscles) for MIlat, this latter being paralleled by poor adjustments of the corresponding, d/c relation-ships (architectural effect independent of tissue stiffness). These findings,1. Show the direct influence of the traction force of peroneal muscles on proximal fibula structure close to the insertion area, and 2. Suggest that, in the studied conditions, the bone mechanostat would proceed beyond its known conception as a regulatory mechanism of structural bone strength.Fil: Nocciolino, Laura Marcela. Universidad Gran Rosario. Centro Universitario de Asistencia, Docencia e Investigación. Unidad de Estudios Biomecánicos Osteo-Musculares ; Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Médicas. Centro de Estudios de Metabolismo Fosfocálcico; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Luscher, Sergio Hugo. Universidad Nacional de Rosario. Facultad de Ciencias Médicas. Centro de Estudios de Metabolismo Fosfocálcico; ArgentinaFil: Pilot, Nicolás. Universidad Gran Rosario. Centro Universitario de Asistencia, Docencia e Investigación. Unidad de Estudios Biomecánicos Osteo-Musculares ; ArgentinaFil: Pisani, Leandro Matias. Universidad Gran Rosario. Centro Universitario de Asistencia, Docencia e Investigación. Unidad de Estudios Biomecánicos Osteo-Musculares ; ArgentinaFil: Mackler, Leandro. Universidad Nacional de Rosario. Facultad de Ciencias Médicas. Centro de Estudios de Metabolismo Fosfocálcico; ArgentinaFil: Cointry, Gustavo Roberto. Manchester Metropolitan University; Reino Unido. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ireland, Alex. Institute of Aerospace Medicine. Division of Space Physiology; AlemaniaFil: Rittweger, Jörn. Institute of Aerospace Medicine. Division of Space Physiology; AlemaniaFil: Ferretti, Jose Luis. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Médicas. Centro de Estudios de Metabolismo Fosfocálcico; Argentina. Universidad Gran Rosario. Centro Universitario de Asistencia, Docencia e Investigación. Unidad de Estudios Biomecánicos Osteo-Musculares ; ArgentinaFil: Capozza, Ricardo Francisco. Universidad Gran Rosario. Centro Universitario de Asistencia, Docencia e Investigación. Unidad de Estudios Biomecánicos Osteo-Musculares ; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Médicas. Centro de Estudios de Metabolismo Fosfocálcico; Argentin

Motor development in infancy and spine shape in early old age: findings from a British birth cohort study

Spine shape changes dramatically in early life, influenced by attainment of developmental milestones such as independent walking. Whether these associations persist across life is unknown. Therefore, we investigated associations between developmental milestones and spine shape, as determined using statistical shape models (SSMs) of lumbar spine from DXA scans in 1327 individuals (688 female) at 60‐64y in the MRC National Survey of Health and Development. Lumbar lordosis angle (L4 inferior endplate to T12 superior endplate) was measured using the two‐line Cobb method. In analyses adjusted for sex, height, lean and fat mass, socioeconomic position and birthweight, later walking age was associated with greater lordosis described by SSM1 (regression coefficient 0.023, 95%CI 0.000‐0.047, p=0.05) and direct angle measurement. Modest associations between walking age and less variation in anterior‐posterior vertebral size caudally (SSM6) were also observed (0.021, 95%CI ‐0.002‐0.044, p=0.07). Sex interactions showed that later walking was associated with larger relative vertebral anterior‐posterior dimensions in men (SSM3; ‐0.043, 95%CI ‐0.075‐0.01, p=0.01) but not women (0.018, 95%CI ‐0.0007‐0.043, p=0.17). Similar associations were observed between age at independent standing and SSMs but there was little evidence of association between sitting age and spine shape. Unadjusted associations between walking age and SSMs 1 and 6 remained similar after adjustment for potential confounders and mediators. This suggests that these associations may be explained by altered mechanical loading of the spine during childhood growth, although other factors could contribute. Early life motor development, particularly walking, may have a lasting effect on features of spine morphology with clinical significance