M. A. Fiatarone Singh

Effects of resistance training on metabolic fitness in children and adolescents: a systematic review

The majority of resistance training (RT) research with children to date has focused on pre‐adolescents and the safety and efficacy of this type of training rather than the potential metabolic health benefits. Our objectives, using computerized databases, were (i) to systematically review studies utilizing RT interventions with children and adolescents <18 years; (ii) to investigate the metabolic health outcomes (adiposity, lipids, insulin, glucose) associated with RT; (iii) to provide recommendations for future investigations. A total of 12 studies met the review criteria. There is only a small amount of evidence that children and adolescents may derive metabolic health‐related adaptations from supervised RT. However, methodological limitations within the body of this literature make it difficult to determine the optimal RT prescription for metabolic fitness in children and adolescents, and the extent and duration of such benefits. More robustly designed single modality randomized controlled trials utilizing standardized reporting and precise outcome assessments are required to determine the extent of health outcomes attributable solely to RT and to enable the development of evidence‐based obesity prevention and treatment strategies in this cohort.

The relationship between knee adduction moment and cartilage and meniscus morphology in women with osteoarthritis

OBJECTIVE The aim of this cross-sectional study is to investigate the relationship between knee adduction moment and knee adduction angular impulse and meniscus, cartilage and bone morphology in women with knee osteoarthritis (OA). METHOD Forty-five women aged >40 years with OA in at least one knee, according to American College of Rheumatology clinical criteria were studied. The knee joint loading was assessed by three-dimensional motion analysis system during gait. Three Tesla magnetic resonance imaging (MRI) with a coronal T2-weighted spin echo sequence was used for evaluating meniscus pathology, and a coronal T1-weighted gradient echo sequence for quantifying cartilage morphology and bone surface size. Cartilage thickness, denuded area and subchondral area in the femorotibial joint was measured using custom software. RESULTS A higher peak knee adduction moment was observed in participants with medial compared to those with lateral tears (2.92+/-1.06 vs -0.46+/-1.7, P<0.001). Participants with a higher knee adduction moment displayed a larger medial meniscus extrusion (r=0.532, P<0.001) and a lower medial meniscus height (r=-0.395, P=0.010). The inverse relationship was observed for the lateral meniscus. A higher knee adduction moment was also associated with a higher ratio of the medial to lateral tibial subchondral bone area (r=0.270, P=0.035). By contrast, cartilage thickness and denuded areas in the femur and tibia were not related to the knee adduction moment. Similar results were found for the relationship between knee adduction angular impulse and meniscus, cartilage and bone morphology. CONCLUSIONS Dynamic knee joint loading is significantly related to meniscus pathology and bone size, but not to cartilage thickness in women with OA.

Estimation of lean body weight in older women with hip fracture

AbstractObjectiveLean body weight (LBW) decreases with age while total body fat increases, resulting in altered drug pharmacokinetics. A semi-mechanistic equation estimating LBW using height, weight and sex has been developed for potential use across a wide range of body compositions. The aim of this study was to determine the ability of the LBW equation to estimate dual energy x-ray absorptiometry-derived fat free mass (FFMDXA) in a population of older women with recent hip fracture.MethodsBaseline, four and 12 month data obtained from 23 women enrolled in the Sarcopenia and Hip Fracture study were pooled to give 58 measurements. LBW was estimated using the equation:

Bone Mineral Measurements: A Comparison of Delayed Gamma Neutron Activation, Dual-Energy X-ray Absorptiometry and Direct Chemical Analysis

LBW(kg) = \frac{{9270 \times Wt}} {{8780 + (244 \times BMI)}}

Midlife managerial experience is linked to late life hippocampal morphology and function

Body composition was classified as: ‘normal’ (BMI <25kg/m2 and not sarcopenic), ‘overweight-obese’ (BMI >25kg/m2 and not sarcopenic), ‘sarcopenic’ (sarcopenic and BMI <25kg/m2), or ‘sarcopenic-obese’ (sarcopenic and BMI >25kg/m2). The ability of the LBW equation to predict FFMDXA was determined graphically using Bland-Altman plots and quantitatively using the method of Sheiner and Beal.ResultsThe mean ± SD age of female participants women was 83±7 years (n=23). Sarcopenia was frequently observed (65.2%). Bland-Altman plots demonstrated an underestimation by the LBW equation compared to FFMDXA. The bias (95% CI) and precision (95% CI) calculated using the method of Sheiner and Beal was 0.5kg (−0.7, 1.66kg) and 4.4kg (−3.7, 12.4kg) respectively for pooled data.ConclusionThis equation can be used to easily calculate LBW. When compared to FFMDXA, the LBW equation resulted in a small underestimation on average in this population of women with recent hip fracture. The degree of bias may not be clinically important although further studies of larger heterogeneous cohorts are needed to investigate and potentially improve the accuracy of this predictive equation in larger clinical cohorts.

The effect of oral nutritional supplements on habitual dietary quality and quantity in frail elders

Abstract: A system in vitro consisting of a femur from a cadaver and soft-tissue equivalent material was used to test the agreement between several techniques for measuring bone mineral. Calcium values measured by delayed gamma neutron activation (DGNA) and bone mineral content (BMC) by Lunar, Hologic and Norland dual-energy X-ray absorptiometers (DXA) were compared with calcium and ash content determined by direct chemical analysis. To assess the effect of soft-tissue thickness on measurements of bone mineral, we had three phantom configurations ranging from 15.0 to 26.0 cm in thickness, achieved by using soft-tissue equivalent overlays. Chemical analysis of the femur gave calcium and ash content values of 61.83 g ± 0.51g and 154.120 ± 0.004 g, respectively. Calcium measured by DGNA did not differ from the ashed amount of calcium at any of the phantom configurations. The BMC measured by DXA was significantly higher, by 3–5%, than the amount determined by chemical analysis for the Lunar densitometer and significantly lower, by 3–6%, for the Norland densitometer (p<0.001–0.024), but only 1% lower (not significant) for the Hologic densitometer. DXA instruments showed a decreasing trend in BMC as the thickness increased from 20.5 to 26.0 cm (p<0.05). However, within the entire thickness range (15.0–26.0 cm), the overall influence of thickness on BMC by DXA was very small. These findings offer insight into the differences in these currently available methods for bone mineral measurement and challenge the comparability of different methods.

Degenerative meniscus tears and mobility impairment in women with knee osteoarthritis

An active cognitive lifestyle has been suggested to have a protective role in the long-term maintenance of cognition. Amongst healthy older adults, more managerial or supervisory experiences in midlife are linked to a slower hippocampal atrophy rate in late life. Yet whether similar links exist in individuals with Mild Cognitive Impairment (MCI) is not known, nor whether these differences have any functional implications. 68 volunteers from the Sydney SMART Trial, diagnosed with non-amnestic MCI, were divided into high and low managerial experience (HME/LME) during their working life. All participants underwent neuropsychological testing, structural and resting-state functional MRI. Group comparisons were performed on hippocampal volume, morphology, hippocampal seed-based functional connectivity, memory and executive function and self-ratings of memory proficiency. HME was linked to better memory function (p = 0.024), mediated by larger hippocampal volume (p = 0.025). More specifically, deformation analysis found HME had relatively more volume in the CA1 sub-region of the hippocampus (p < 0.05). Paradoxically, this group rated their memory proficiency worse (p = 0.004), a result correlated with diminished functional connectivity between the right hippocampus and right prefrontal cortex (p < 0.001). Finally, hierarchical regression modelling substantiated this double dissociation.