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The aim of this study is to determine if bone mineral density (BMD) and bone asymmetry differs between female cricket fast bowlers, spin bowlers and batters. BMD was determined at the total body, lumbar spine, and proximal femurs in 12 fast bowlers, 13 batters and 11 spin bowlers from pre-season DXA scans. High Z-scores at the total body, lumbar spine, and proximal femur were observed in all cricketers (mean Z-scores: +1.4 to +3.3) compared with a general age matched reference population. Fast bowlers had significantly greater BMD on the contralateral side of the lumbar spine compared with the ipsilateral side (

Introduction: Localised bone mineral density (BMD) adaptation of the lumbar spine, particularly on the contralateral side to the bowling arm, has been observed in elite male cricket fast bowlers. No study has investigated this in adolescents, or the role of fast bowling technique on lumbar BMD adaptation. This study aims to investigate lumbar BMD adaptation in adolescent cricket fast bowlers, and its relationship with fast bowling technique. \ud \ud Methods: 39 adolescent fast bowlers underwent antero-posterior DXA scan of their lumbar spine. Hip, lumbopelvic and thoracolumbar joint kinematics, and vertical ground reaction kinetics were determined using 3D motion capture and force plates. Significant partial (covariate: fat free mass) and bivariate correlations of the technique parameters with whole lumbar (L1-L4) BMD and BMD asymmetry (L3 and L4) were advanced as candidate variables for multiple stepwise linear regression.\ud \ud Results: Adolescent fast bowlers demonstrated high lumbar Z-Scores (+1.0; 95%CI: 0.7 – 1.4) and significantly greater BMD on the contralateral side of L3 (9.0%; 95%CI: 5.8 – 12.1%) and L4 (8.2%; 95%CI: 4.9 – 11.5%). Maximum contralateral thoracolumbar rotation and maximum ipsilateral lumbopelvic rotation in the period between back foot contact (BFC) and ball release (BR), as well as contralateral pelvic drop at front foot contact (FFC), were identified as predictors of L1-L4 BMD, explaining 65% of the variation. Maximum ipsilateral lumbopelvic rotation between BFC and BR, as well as ipsilateral lumbopelvic rotation and contralateral thoracolumbar side flexion at BR, were predictors of lumbar asymmetry within L3 and L4. \ud \ud Conclusion: Thoracolumbar and lumbopelvic motion are implicated in the aetiology of the unique lumbar bone adaptation observed in fast bowlers whereas vertical ground reaction force, independent of body mass, was not. This may further implicate the osteogenic potential of torsional rather than impact loading in exercise-induced adaptation.

Exercise and physical activity can improve bone strength and the risk of falls, which may offer benefits in the prevention and management of osteoporosis. However, uncertainty about the types of exercise that are safe and effective instigates lack of confidence in people with osteoporosis and health professionals. Existing guidelines leave some questions unresolved. This consensus statement aimed to determine the physical activity and exercise needed to optimise bone strength, reduce fall and fracture risk, improve posture and manage vertebral fracture symptoms, while minimising potential risks in people with osteoporosis. The scope of this statement was developed following stakeholder consultation. Meta-analyses were reviewed and where evidence was lacking, individual studies or expert opinion were used to develop recommendations. A multidisciplinary expert group reviewed evidence to make recommendations, by consensus when evidence was not available. Key recommendations are that people with osteoporosis should undertake (1) resistance and impact exercise to maximise bone strength; (2) activities to improve strength and balance to reduce falls; (3) spinal extension exercise to improve posture and potentially reduce risk of falls and vertebral fractures. For safety, we recommend avoiding postures involving a high degree of spinal flexion during exercise or daily life. People with vertebral fracture or multiple low trauma fractures should usually exercise only up to an impact equivalent to brisk walking. Those at risk of falls should start with targeted strength and balance training. Vertebral fracture symptoms may benefit from exercise to reduce pain, improve mobility and quality of life, ideally with specialist advice to encourage return to normal activities. Everyone with osteoporosis may benefit from guidance on adapting postures and movements. There is little evidence that physical activity is associated with significant harm, and the benefits, in general, outweigh the risks.

Elite adult male fast bowlers have high lumbar spine bone mineral, particularly on the contralateral side to their bowling arm. It is thought that bone possesses its greatest ability to adapt to loading during adolescence, but it is unknown at what age the greatest changes in lumbar bone mineral and asymmetry develops in fast bowlers.ObjectivesThis study aims to evaluate the adaptation of the lumbar vertebrae in fast bowlers compared to controls and how this is associated with age.Methods91 male fast bowlers and 84 male controls aged 14–24 years had between one and three annual anterior-posterior lumbar spine dual-energy-X-ray absorptiometry scans. Total (L1-L4) and regional ipsilateral and contralateral L3 and L4 (respective to bowling arm) bone mineral density and content (BMD/C) were derived. Multilevel models examined the differences in lumbar bone mineral trajectories between fast bowlers and controls.ResultsAt L1-L4 BMC and BMD, and contralateral BMD sites, fast bowlers demonstrated a greater negative quadratic pattern to their accrual trajectories than controls. Fast bowlers had greater increases in BMC in L1-L4 between 14 and 24 years of 55% compared with controls (41%). Within vertebra, asymmetry was evident in all fast bowlers and increased by up to 13% in favour of the contralateral side.ConclusionsLumbar vertebral adaptation to fast bowling substantially increased with age, particularly on the contralateral side. The greatest accrual was during late adolescence and early adulthood, which may correspond with the increasing physiological demands of adult professional sport.

Endurance athletes expend large amounts of energy in prolonged high-intensity exercise and, due to the weight-sensitive nature of most endurance sports, often practice periods of dietary restriction. The Female Athlete Triad and Relative Energy Deficiency in Sport models consider endurance athletes at high-risk for suffering from low energy availability and associated health complications, including an increased chance of bone stress injury. Several studies have examined the effects of low energy availability on various parameters of bone structure and markers of bone (re)modelling; however, there are differences in findings and research methods and critical summaries are lacking. It is difficult for athletes to reduce energy expenditure or increase energy intake (to restore energy availability) in an environment where performance is a priority. Development of an alternative tool to help protect bone health would be beneficial. High-impact exercise can be highly osteogenic and energy efficient; however, at present, it is rarely utilized to promote bone health in endurance athletes. Therefore, with a view to reducing the prevalence of bone stress injury, the objectives of this review are to evaluate the effects of low energy availability on bone health in endurance athletes and explore whether a high-impact exercise intervention may help to prevent those effects from occurring.

We provided evidence that a 6-month regular hopping exercise intervention can increase trabecular number and possibly trabecular volume fraction of the distal tibia. Our novel localised analysis demonstrated region-specific changes, predominantly in the anterior region, in postmenopausal women. The localisation of bone remodelling and microarchitectural adaptation to exercise loading has not been demonstrated previously in vivo in humans. The aim of this study is to assess the feasibility of using 3D image registration and high-resolution peripheral quantitative computed tomography (HR-pQCT) to investigate the effect of high-impact exercise on human trabecular bone variables and remodelling rate across the distal tibia. Ten postmenopausal women were recruited for 6-month unilateral hopping exercises, with HR-pQCT scans taken of both exercise leg (EL) and control leg (CL) for each participant before and after the intervention. A 3D image registration was used to ensure measurements were taken at the same region. Short-term reproducibility tests were conducted prior to the assessment using identical setup. The results were assessed comparing CL and EL, and interaction (time × leg) using a two-way repeated measures analysis of variance (RM-ANOVA). Across the whole tibia, we observed significant increases in trabecular number (Tb.N) (+ 4.4%) and trabecular bone formation rate (tBFR) (3.3%), and a non-significant increase in trabecular bone volume fraction (BV/TV) (+ 1%) in the EL. Regional resorption was higher in the CL than the EL, with this difference being statistically significant at the lateral tibia. In the EL, tBFR was significantly higher in the anterior region than the medial but a trabecular bone resorption rate (tBRR) showed no significant regional variation. Conversely in the CL, both tBFR and tBRR were significantly higher in the anterior and lateral than the medial region. We demonstrated that it was possible to detect exercise-related bone adaptation with 3D registration of HR-pQCT scan data. Regular hopping exercise increased Tb.N and possibly BV/TV across the whole distal tibia. A novel finding of the study was that tBFR and tBRR responses to loading were localised: changes were achieved by formation rate exceeding resorption rate in the exercise leg, both globally and at the anterior region where turnover was greatest. clinicaltrials.gov : NCT03225703

Introduction: Lumbar bone stress injuries (LBSI) are the most prevalent injury in cricket. While fast bowling technique has been implicated in the aetiology of LBSI, no previous study has attempted to prospectively analyse fast bowling technique and its relationship to LBSI. The aim of this study was to explore technique differences between elite cricket fast bowlers with and without subsequent LBSI. \ud \ud Methods: Kinematic and kinetic technique parameters previously associated with LBSI were determined for 50 elite male fast bowlers. \ud Group means were compared using independent samples t-tests to identify differences between bowlers with and without a prospective LBSI. Significant parameters were advanced as candidate variables for a binary logistic regression analysis. \ud \ud Results: Of the 50 bowlers, 39 sustained a prospective LBSI. Significant differences were found between injured and non-injured bowlers in: rear knee angle, rear hip angle, thoracolumbar side flexion angle and thoracolumbar rotation angle at back foot contact (BFC); the front hip angle, pelvic tilt orientation and lumbopelvic angle at front foot contact (FFC); the thoracolumbar side flexion angle at ball release and the maximum front hip angle and ipsilateral pelvic drop orientation. A binary logistic model, consisting of rear hip angle at BFC and lumbopelvic angle at FFC, correctly predicted 88% of fast bowlers according to injury history and significantly increased the odds of sustaining an LBSI (odds ratio: 0.88 and 1.25 respectively). \ud \ud Conclusion: Lumbopelvic motion is implicated in the aetiology of LBSI in fast bowling with inadequate lumbo-pelvi-femoral complex control a potential cause. This research will aid the identification of fast bowlers at risk of LBSI, as well as enhancing coaching and rehabilitation of fast bowlers from LBSI.

Cricket fast bowling is associated with a high prevalence of lumbar bone stress injuries (LBSI), especially in adolescent bowlers. This has not been sufficiently explained by risk factors identified in adult players. This study aimed to examine the incidence of LBSI in adolescent fast bowlers over a prospective study and potential risk factors. Forty asymptomatic male fast bowlers (aged 14-17 years) received baseline and annual lumbar dual-energy X-ray absorptiometry (DXA) and magnetic resonance imaging (MRI) scans, and musculoskeletal and bowling workload assessment; 22 were followed up after one year. LBSI prevalence at baseline and annual incidence were calculated. Potential risk factors were compared between the injured and uninjured groups using T-tests with Hedges' g effect sizes. At baseline, 20.5% of participants had at least one LBSI. Subsequent LBSI incidence was 27.3 ± 18.6 injuries per 100 players per year (mean ± 95% CI). Injured bowlers were older on average at the beginning of the season preceding injury (16.8 versus 15.6 years, g = 1.396, P = 0.047). LBSI risk may coincide with increases in bowling workload and intensity as bowlers step up playing levels to more senior teams during late adolescence whilst the lumbar spine is immature and less robust.

Objective:To investigate changes in socio-economic inequalities in growth in height, weight, BMI and grip strength in children born during 1955–1993 in Guatemala, a period of marked socio-economic-political change.Design:We modelled longitudinal data on height, weight, BMI and hand grip strength using Super-Imposition by Translation and Rotation (SITAR). Internal Z-scores summarising growth size, timing and intensity (peak growth velocity, e.g. cm/year) were created to investigate inequalities by socio-economic position (SEP; measured by school attended). Interactions of SEP with date of birth were investigated to capture secular changes in inequalities.Setting:Urban and peri-urban schools in the region of Guatemala City, Guatemala.Participants:Participants were 40 484 children and adolescents aged 3–19 years of Ladino and Maya ancestry (nobservations 157 067).Results:The difference in height (SITAR size) between lowest and highest SEP decreased from −2·0 (95 % CI −2·2, −1·9) sd to −1·4 (95 % CI −1·5, −1·3) sd in males, and from −2·0 (95 % CI −2·1, −1·9) sd to −1·2 (95 % CI −1·3, −1·2) sd in females over the study period. Inequalities also reduced for weight, BMI and grip strength, due to greater secular increases in lowest-SEP groups. The puberty period was earlier and shorter in higher-SEP individuals (earlier SITAR timing and higher SITAR intensity). All SEP groups showed increases in BMI intensity over time.Conclusions:Inequality narrowed between the 1960s and 1990s. The lowest-SEP groups were still >1 sd shorter than the highest. Risks remain for reduced human capital and poorer population health for urban Guatemalans.

Bone stress injury (BSI) is prevalent in female distance runners. Menstrual disturbances are associated with impaired bone health in endurance athletes. This study aimed to investigate the association between menstrual function and BSI and explore whether plyometric training may protect against BSI in individuals with menstrual disturbances. Competitive female distance runners (n = 183) aged 18-40 years were surveyed for training habits, menstrual function, and BSI, during the previous 12 months. Oligo/amenorrhoea during the previous 12 months (

Funder: Loughborough University; funder-id: http://dx.doi.org/10.13039/501100000857, Funder: Peter Harrison Foundation, The objective of this scoping review was to map the evidence on measurement properties of body composition tools to assess whole-body and regional fat and fat-free mass in adults with SCI, and to identify research gaps in order to set future research priorities. Electronic databases of PubMed, EMBASE and the Cochrane library were searched up to April 2020. Included studies employed assessments related to whole-body or regional fat and/or fat-free mass and provided data to quantify measurement properties that involved adults with SCI. All searches and data extractions were conducted by two independent reviewers. The scoping review was designed and conducted together with an expert panel (n = 8) that represented research, clinical, nutritional and lived SCI experience. The panel collaboratively determined the scope and design of the review and interpreted its findings. Additionally, the expert panel reached out to their professional networks to gain further stakeholder feedback via interactive practitioner surveys and workshops with people with SCI. The research gaps identified by the review, together with discussions among the expert panel including consideration of the survey and workshop feedback, informed the formulation of future research priorities. A total of 42 eligible articles were identified (1,011 males and 143 females). The only tool supported by studies showing both acceptable test-retest reliability and convergent validity was whole-body dual-energy x-ray absorptiometry (DXA). The survey/workshop participants considered the measurement burden of DXA acceptable as long as it was reliable, valid and would do no harm (e.g. radiation, skin damage). Practitioners considered cost and accessibility of DXA major barriers in applied settings. The survey/workshop participants expressed a preference towards simple tools if they could be confident in their reliability and validity. This review suggests that future research should prioritize reliability and validity studies on: (1) DXA as a surrogate ‘gold standard’ tool to assess whole-body composition, regional fat and fat-free mass; and (2) skinfold thickness and waist circumference as practical low-cost tools to assess regional fat mass in persons with SCI, and (3) females to explore potential sex differences of body composition assessment tools. Registration review protocol: CRD42018090187 (PROSPERO).

© 2019 American Society for Bone and Mineral Research High-impact exercise can improve femoral neck bone mass but findings in postmenopausal women have been inconsistent and there may be concern at the effects of high-impact exercise on joint health. We investigated the effects of a high-impact exercise intervention on bone mineral density (BMD), bone mineral content (BMC), and section modulus (Z) as well as imaging biomarkers of osteoarthritis (OA) in healthy postmenopausal women. Forty-two women aged 55 to 70 years who were at least 12 months postmenopausal were recruited. The 6-month intervention consisted of progressive, unilateral, high-impact exercise incorporating multidirectional hops on one randomly assigned exercise leg (EL) for comparison with the contralateral control leg (CL). Dual-energy X-ray absorptiometry (DXA) was used to measure BMD, BMC, and Z of the femoral neck. Magnetic resonance imaging (MRI) of the knee joint was used to analyze the biochemical composition of articular cartilage using T2 relaxometry and to analyze joint pathology associated with OA using semiquantitative analysis. Thirty-five participants (61.7 ± 4.3 years) completed the intervention with a mean adherence of 76.8% ± 22.5%. Femoral neck BMD, BMC, and Z all increased in the EL (+0.81%, +0.69%, and +3.18%, respectively) compared to decreases in the CL (−0.57%, −0.71%, and −0.75%: all interaction effects p < 0.05). There was a significant increase in mean T2 relaxation times (main effect of time p = 0.011) but this did not differ between the EL and CL, indicating no global effect. Semiquantitative analysis showed high prevalence of bone marrow lesions (BML) and cartilage defects, especially in the patellofemoral joint (PFJ), with no indication that the intervention caused pathology progression. In conclusion, a high-impact exercise intervention that requires little time, cost, or specialist equipment improved femoral neck BMD with no negative effects on knee OA imaging biomarkers. Unilateral high-impact exercise is a feasible intervention to reduce hip fracture risk in healthy postmenopausal women. © 2019 American Society for Bone and Mineral Research.

The aims of this study were to determine whether lumbar areal bone mineral density differed between cricket fast bowlers with and without lumbar stress fracture, and whether bone mineral density trajectories differed between groups during rehabilitation.Cross-sectional and cohort.29 elite male fast bowlers received a post-season anteroposterior lumbar dual-energy X-ray absorptiometry scan and a lumbar magnetic resonance imaging scan to determine stress fracture status. Participants were invited for three additional scans across the 59 weeks post baseline or diagnosis of injury. Bone mineral density was measured at L1 - L4 and ipsilateral and contralateral L3 and L4 sites. Independent-sample t-tests determined baseline differences in bone mineral density and multilevel models were used to examine differences in bone mineral density trajectories over time between injured and uninjured participants.17 participants with lumbar stress fracture had lower baseline bone mineral density at L1 - L4 (7.6 %, p = 0.034) and contralateral sites (8.8-10.4 %, p = 0.038-0.058) than uninjured participants. Bone mineral density at all sites decreased 1.9-3.0 % by 20-24 weeks before increasing to above baseline levels by 52 weeks post injury.Injured fast bowlers had lower lumbar bone mineral density at diagnosis that decreased following injury and did not return to baseline until up to a year post-diagnosis. Localised maladaptation of bone mineral density may contribute to lumbar stress fracture. Bone mineral density loss following injury may increase risk of recurrence, therefore fast bowlers require careful management when returning to play.

Objectives: Sarcopenia is characterised by loss of skeletal muscle mass and strength with adverse outcomes: physical disability, poor quality of life and death. Low muscle mass and strength are risk factors for falls, although there are few data available on the prevalence of sarcopenia in fallers. This study aimed to determine prevalence of sarcopenia in older people referred to a falls clinic. Methods: Consecutive patients referred to a secondary care falls unit were recruited. Sarcopenia was diagnosed using the European Working Group on Sarcopenia definition (low muscle mass and function) and cut-off points. Bio-impedance measured appendicular skeletal muscle mass. Gait speed and grip strength were functional measures. Results: Fifty-eight patients were recruited. Mean (SD) grip strength for women and men respectively were 17.9 (4.9) and 29.9(8.7) kg, mean (SD) gait speeds were 0.61(0.18) and 0.72 (0.4) m/s, mean (SD) appendicular skeletal muscle index in women and men were 6.98(1.0) and 7.85 (1.0) kg/m2 (p=0.018). Prevalence of sarcopenia was 9.8% (95% CI=1.6%-18%). Conclusions: Sarcopenia, as measured by bio-impedance is not uncommon in older people accessing a secondary care falls clinic. Bio-impedance was simple to perform, although further validation against gold standard methods is needed. As nutritional and exercise interventions for sarcopenia are available, simple methods for diagnosing sarcopenia in fallers should be considered.

Purpose: To evaluate the tracking of within-athlete changes in criterion measures of whole-body fat percentage (BF%; dual-energy X-ray absorptiometry) with skinfold thickness (Σ 4, 6, or 8) in wheelchair basketball players. Methods: Dual-energy X-ray absorptiometry-derived whole BF% and Σ 4, 6, or 8 skinfolds were obtained at 5 time points over 15 months (N = 16). A linear mixed model with restricted maximum likelihood (random intercept, with identity covariance structure) to derive the within-athlete prediction error for predicting criterion BF% from Σ skinfolds was used. This prediction error allowed us to evaluate how well a simple measure of the Σ skinfolds could track criterion changes in BF %; that is, the authors derived the change in Σ skinfolds that would have to be observed in an individual athlete to conclude that a substantial change in criterion BF% had occurred. Data were log-transformed prior to analysis. Results: The Σ 8 skinfolds was the most precise practical measure for tracking changes in BF%. For the monitoring of an individual player, a change in Σ 8 skinfolds by a factor of greater than 1.28 (multiply or divide by 1.28) is associated with a practically meaningful change in BF% (≥1 percentage point). Conclusions: The Σ 8 skinfolds can track changes in BF% within individuals with reasonable precision, providing a useful field monitoring tool in the absence of often impractical criterion measures.

Gregory Summers,1 Alison Booth,1 Katherine Brooke-Wavell,2 Tharaq Barami,1,3 Stacy Clemes21Department of Rheumatology, Royal Derby Hospital, Derby, UK; 2School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK; 3Kettering General Hospital, Kettering, UKObjective: In rheumatoid arthritis (RA) patients, low levels of physical activity (PA) and high levels of sedentary behavior (SB) may play a role in enhancing cardiovascular risk. We do not know how long-term control of disease activity impacts upon daily PA levels and if treated patients attain PA levels seen in healthy controls. We therefore compared habitual levels of PA and SB between female RA patients with low disease activity achieved by anti-tumor necrosis factor (TNF) therapy, those with active arthritis (aRA) and non-RA controls.Methods: We carried out a cross-sectional comparison of 40 RA patients on anti-TNF therapy for >2 years with DAS283.2 (aRA) and 34 healthy controls (C) with the groups matched for age and body mass index. PA was assessed using the ActiGraph accelerometer to determine step count and time spent in moderate-to-vigorous physical activity (MVPA), light activity and sedentary time.Results: Daily step count was 72% higher in tRA and 40% higher in C in comparison to aRA (p

ObjectivesSince much of the previous epidemiological research into lumbar stress fracture was conducted, there has been a marked increase in the amount of cricket being played. The aims were to determine the incidence and prevalence of lumbar stress fracture in English County Cricket fast bowlers between 2010 and 2016, determine the association with match bowling workload and observe seasonal variation in workload and injury.MethodsLumbar stress fracture incidence and prevalence rates were calculated using new international methods for epidemiology in 368 professional English fast bowlers from 2010 to 2016. Workload variables were compared between lumbar stress fracture case and non-injured control groups, before entry in a logistic regression.ResultsFifty-seven lumbar stress fractures (mean age 22.81) were reported. Injury was most common in July and September. Match incidence was 0.16 lumbar stress fractures per 10 000 deliveries, annual incidence was 2.46 lumbar stress fractures per 100 fast bowlers and annual prevalence of lumbar stress fractures was 1.67% of squad days. Significant workload variables were observed between cases and controls. A peak 7-day workload of greater than 234 deliveries significantly increased the odds of sustaining a lumbar stress fracture 11-fold compared with bowling fewer than 197 deliveries.ConclusionLumbar stress fractures are common in young fast bowlers possibly due to immaturity of the lumbar spine. The condensed early and late-season schedule may be causing periods of overuse, resulting in an increase in incidence of lumbar stress fracture. Reduction of workload in young fast bowlers is needed to reduce incidence.

Childhood IQ has been used to predict later life outcomes across disciplines in epidemiology, education, and psychology. Most often only a single childhood IQ test is available or is used for these purposes in the belief that IQ is stable across the life course. The primary aim of this study was to examine the longitudinal stability of individuals' IQ test scores derived from school-age tests. The secondary aim was to investigate the association of the pre-adult scores with later life intelligence scores. The longitudinal pre-adult IQ scores of 42 high socioeconomic status Guatemalans born 1941-1953 were analysed and showed low stability of longitudinal test scores. Fluctuations of >1SD were found for 59.5% of the sample. The same participants, aged 64-76 years, were re-assessed and average pre-adult IQ explained 12% of variance in the older age intelligence score. The reasons behind the longitudinal instability in test scores reported in this study remains unknown but the results suggest single point measurements of intelligence before adulthood should be regarded with some caution.

Objectives The objective of this study was to investigate the association between physical growth in preadult life with five outcomes at ages 64 to 76: weight, body mass index (BMI), estimated body fat percentage, hand grip strength, and mortality. Methods Super‐imposition by translation and rotation (SITAR) growth curves of 40 484 Guatemalan individuals aged 3 to 19 years were modeled for the parameters of size, timing and intensity (peak growth velocity, eg, cm/year) of height, weight, BMI, and grip strength. Associations between the SITAR parameters and old age outcomes were tested using linear and binary logistic regression for a follow‐up sample of high socioeconomic status (SES) Guatemalans, of whom 50 were aged 64 to 76 years at re‐measurement and 45 died prior to the year 2017. Results SITAR models explained 69% to 98% of the variance in each outcome, with height the most precise. Individuals in the follow‐up sample who had a higher BMI before the age of 20 years had higher estimated body fat (B = 1.4 CI −0.02‐2.8) and BMI (B = 1.2, CI 0.2‐2.2) at the ages of 64 to 76 years. Those who grew slower in height but faster in weight and BMI before the age of 20 years had higher BMI and body fat later in life. Conclusions These findings highlight the importance of a life course perspective on health and mortality risk. Childhood exposures leading to variation in preadult growth may be key to better understanding health and mortality risks in old age.

The purpose of this study was to assess the agreement in body composition measurements of wheelchair athletes using skinfolds, bio-impedance analysis (BIA) and air displacement plethysmography (ADP) relative to dual-energy X-ray absorptiometry (DXA). A secondary objective was to develop new skinfold prediction equations to estimate %fat for this sample. 30 wheelchair games players were recruited and the body composition outcomes of BIA, ADP, and skinfolds were compared to the DXA outcomes by a paired-samples t-test (systematic bias), intraclass correlation (ICC, relative agreement) and Bland-Altman plots (absolute agreement). Regression models to predict the %fat as measured by DXA by the sum of skinfolds or BIA were calculated. Results showed that the predictions of %fat when using BIA, ADP or skinfolds systematically underestimated the %fat mass as measured by the DXA. All ICC values, except for the measurement of fat (kg) by ADP (ICC=0.702), were below 0.7. New prediction models found the Sigma 7 skinfolds and calf circumference as the best model to predict %fat (R-2=0.84). In conclusion, BIA, ADP and existing skinfolds equations should be used with caution when estimating %fat of wheelchair athletes with substantial body asymmetry, lower body muscular atrophy and upper body muscular development.

OBJECTIVE: Quantifying spatial distribution of trabecular bone mechanical competence and microstructure is important for early diagnosis of skeletal disorders and potential risk of fracture. The objective of this study was to determine a spatial distribution of trabecular mechanical and morphological properties in human distal tibia and examine the contribution of regional variability of trabecular microarchitecture to mechanical competence. METHODS: A total of 340 representative volume elements at five anatomic regions of trabecular bone - anterior, posterior, lateral, medial and centre - from ten white European-origin postmenopausal women were studied. Region-specific trabecular parameters such as trabecular volume fraction, trabecular thickness, trabecular number, trabecular surface area, trabecular separation, plate-like structure fraction and finite element analysis of trabecular stiffness were determined based on in-vivo high resolution peripheral quantitative computed tomographic (HR-pQCT) images of distal tibiae from ten postmenopausal women. Mean values were compared using analysis of variance. The correlations between morphological parameters and stiffness were calculated. RESULTS: Significant regional variation in trabecular microarchitecture of the human distal tibia was observed (0.001 ≤ p ≤ 0.05), with up to 106% differences between lowest (central and anterior) and highest (medial and posterior) regions. Higher proportion of plate-like trabecular morphology (63% and 53%) was found in medial and posterior regions in the distal tibia. Stiffness estimated from finite element models also differed significantly (0.001 ≤ p ≤ 0.05), with stiffness being 4.5 times higher in the highest (medial) than lowest (central) regions. The bone volume fraction was the strongest correlate of stiffness in all regions. CONCLUSION: A novel finding of this study is the fact that significant regional variation of stiffness derived from two-phased FEA model with individual trabecula representation correlated highly to regional morphology obtained from in-vivo HR-pQCT images at the distal tibia. The correlations between regional morphological parameters and mechanical competence of trabecular bone were consistent at all regions studied, with regional BV/TV showing the highest correlation. The method developed for regional analysis of trabecular mechanical competence may offer a better insight into the relationship between mechanical behaviour and microstructure of bone. The findings provide evidence needed to further justify a larger-cohort feasibility study for early detection of bone degenerative diseases: examining regional variations in mechanical competence and trabecular specifications may allow better understanding of fracture risks in addition to others contributing factors.

High impact exercise programmes can improve bone strength, but little is known about whether this type of training further benefits fracture risk by improving physical function in older people. Objectives: This study investigated the influence of high impact exercise on balance, muscle function and morphology in older men. Methods: Fifty, healthy men (65-80 years) were assigned to a 6-month multidirectional hopping programme (TG) and twenty age and physical activity matched volunteers served as controls (CG). Before and after training, muscle function (hop performance, leg press and plantar- and dorsiflexion strength) and physiological determinants (muscle thickness and architecture) as well as balance control (sway path, one leg stance duration) were measured. Resting gastrocnemius medialis (GM) muscle thickness and architecture were assessed using ultrasonography. Results: Significant improvements in hop impulse (+12%), isometric leg-press strength (+4%) and ankle plantarflexion strength (+11%), dorsiflexor strength (+20%) were found in the TG compared to the CG (ANOVA interaction, P˂0.05) and unilateral stance time improved over time for TG. GM muscle thickness indicated modest hypertrophy (+4%), but muscle architecture was unchanged. Conclusion: The positive changes in strength and balance after high impact and odd impact training would be expected to improve physical function in older adults.

Studies of stress fracture (SF) incidence are limited in number and geographical location; this study determined the incidence of SF injury in female endurance athletes based in the United Kingdom. A total of 70 athletes aged between 18 and 45 years were recruited and prospectively monitored for 12 months. Questionnaires at baseline and 12 months assessed SF, menstrual and training history, eating psychopathology, and compulsive exercise. Peak lower leg muscle strength was assessed in both legs using an isometric muscle rig. Bone mineral density (BMD) of total body, spine, hip, and radius was assessed using dual X-ray absorptiometry. Among the 61 athletes who completed the 12-month monitoring, two sustained a SF diagnosed by magnetic resonance imaging, giving an incidence rate (95% confidence intervals) of 3.3 (0.8, 13.1) % of the study population sustaining a SF over 12 months. The SF cases were 800 m runners aged 19 and 22 years, training on average 14.2 h a week, eumenorrheic with no history of menstrual dysfunction. Case 1 had a higher than average energy intake and low eating psychopathology and compulsive exercise scores, while the reverse was true in case 2. BMD in both cases was similar to mean values in the non-SF group. The incidence of SF in our female endurance athlete population based in the United Kingdom was 3.3%, which is lower than previously reported. Further work is needed to confirm the current incidence of SF and evaluate the associated risk factors.

Background: Anti-TNF therapy has revolutionised the management of rheumatoid arthritis (RA) with rapid and sustained improvements in pain, function and quality of life. However, we do not know how this impacts upon habitual daily physical activity and whether treated patients attain activity levels seen in healthy controls. This study aimed to compare the physical activity levels of patients whose RA was well controlled on long-term anti-TNF therapy to RA patients with active arthritis and non-RA controls. Methods: Participants were patients on anti-TNF for more than two years (tRA) with DAS 3.2 (aRA) and healthy controls (C), matched for age and BMI. Physical activity was assessed using the Actigraph GT3x+ accelerometer, worn throughout waking hours for seven days to determine time spent in light activity, moderate to vigorous physical activity (MVPA) and sedentary time. The International Physical Activity Questionnaire (IPAQ) was also completed. Groups were compared using analysis of variance with Bonferroni post hoc tests; Kruskal-Wallis or Mann-Whitney U- test as appropriate. Results: RA disease duration was significantly greater in tRA than aRA. Groups did not differ significantly in age, height, weight or body mass index (Table). Daily step count was significantly lower in aRA than tRA and C. Sedentary time (as a proportion of wear time) was significantly greater in aRA than tRA, whilst the reverse was true for light activity time. MVPA time was significantly lower in both RA groups than in controls. IPAQ questionnaires demonstrated significant differences between groups, with substantially higher values in C than RA groups in total METs and MET-minutes per week in domestic and garden, leisure, walking activities as well as total moderate and vigorous activities. RA patients had lower moderate to vigorous activity time than controls, regardless of treatment. aRA had lower light activity time, and more sedentary time, than tRA Conclusion: Moderate to vigorous physical activity should be promoted in all RA patients as even those with well controlled disease exhibit a deficit in comparison to controls

The purpose of this study was to assess the reproducibility of body composition measurements by dual-energy X-ray absorptiometry (DXA) in 12 elite male wheelchair basketball players (age 31 ± 7 years, BMI 21 ± 2 kg/m(2) and onset of disability 25 ± 9 years). Two whole body scans were performed on each participant in the supine position on the same day, using Lunar Prodigy Advance DXA (GE Lunar, Madison, WI, USA). Participants dismounted from the scanning table and were repositioned in-between the first and second scan. Whole body coefficient of variation (CV) values for bone mineral content (BMC), fat mass (FM) and soft tissue lean mass (LTM) were all2.0%. With the exclusion of arm FM (CV = 7.8%), CV values ranged from 0.1 to 3.7% for all total body and segmental measurements of BMC, FM and LTM. The least significant change that can be attributed to the effect of treatment intervention in an individual is 1.0 kg, 1.1 kg, 0.12 kg for FM, LTM, and BMC, respectively. This information can be used to determine meaningful changes in body composition when assessed using the same methods longitudinally. Whilst there may be challenges in the correct positioning of an individual with disability that can introduce greater measurement error, DXA is a highly reproducible technique in the estimation of total and regional body composition of elite wheelchair basketball athletes.

BACKGROUND: whole-body vibration training may improve neuromuscular function, falls risk and bone density, but previous studies have had conflicting findings. OBJECTIVE: this study aimed to evaluate the influence of vertical vibration (VV) and side-alternating vibration (SV) on musculoskeletal health in older people at risk of falls. DESIGN: single-blind, randomised, controlled trial comparing vibration training to sham vibration (Sham) in addition to usual care. PARTICIPANTS: participants were 61 older people (37 women and 24 men), aged 80.2 + 6.5 years, referred to an outpatient falls prevention service. METHODS: participants were randomly assigned to VV, SV or Sham in addition to the usual falls prevention programme. Participants were requested to attend three vibration sessions per week for 12 weeks, with sessions increasing to six, 1 min bouts of vibration. Falls risk factors and neuromuscular tests were assessed, and blood samples collected for determination of bone turnover, at baseline and following the intervention. RESULTS: chair stand time, timed-up-and-go time, fear of falling, NEADL index and postural sway with eyes open improved in the Sham group. There were significantly greater gains in leg power in the VV than in the Sham group and in bone formation in SV and VV compared with the Sham group. Conversely, body sway improved less in the VV than in the Sham group. Changes in falls risk factors did not differ between the groups. CONCLUSIONS: whole-body vibration increased leg power and bone formation, but it did not provide any additional benefits to balance or fall risk factors beyond a falls prevention programme in older people at risk of falls. Language: en

Four decades of socioeconomic inequalities and secular changes in the physical growth of Guatemalans [abstract]

Whilst extensive research has detailed the loss of muscle strength with ageing for isolated single joint actions, there has been little attention to power production during more functionally relevant multiple joint movements. The extent to which force or velocity are responsible for the loss in power with ageing is also equivocal. The aim of this study was to evaluate the contribution of force and velocity to the differences in power with age by comparing the force–velocity and power–velocity relationships in young and older men during a multiple joint leg press movement. Twenty-one older men (66 ± 3 years) and twenty-three young men (24 ± 2 years) completed a series of isometric (maximum and explosive) and dynamic contractions on a leg press dynamometer instrumented to record force and displacement. The force–velocity relationship was lower for the older men as reflected by their 19 % lower maximum isometric strength (p

Field-based assessments provide a cost-effective and accessible alternative to dual-energy X-ray absorptiometry (DXA) for practitioners determining body composition in athletic populations. It remains unclear how the range of physical impairments classifiable in wheelchair sports may affect the utility of field-based body composition techniques. The present study assessed body composition using DXA in 14 wheelchair games players who were either wheelchair dependent (non-walkers; n = 7) or relied on a wheelchair for sports participation only (walkers; n = 7). Anthropometric measurements were used to predict body fat percentage with existing regression equations established for able-bodied persons by Sloan and Weir, Durnin and Womersley, Lean et al, Gallagher et al, and Pongchaiyakul et al. In addition, linear regression analysis was performed to calculate the association between body fat percentage and BMI, waist circumference, sum of 6 skinfold thickness and sum of 8 skinfold thickness. Results showed that non-walkers had significantly lower total lean tissue mass (46.2 ± 6.6 kg vs. 59.4 ± 8.2 kg, P = 0.006) and total body mass (65.8 ± 4.2 kg vs. 79.4 ± 14.9 kg; P = 0.05) than walkers. Body fat percentage calculated from most existing regression equations was significantly lower than that from DXA, by 2 to 9% in walkers and 8 to 14% in non-walkers. Of the anthropometric measurements, the sum of 8 skinfold thickness had the lowest standard error of estimation in predicting body fat content. In conclusion, existing anthropometric equations developed in able-bodied populations substantially underestimated body fat content in wheelchair athletes, particularly non-walkers. Impairment specific equations may be needed in wheelchair athletes.

Introduction Exercise can increase bone strength, but to be effective in reducing fracture risk, exercise must be feasible enough to be adopted into daily life and influence potentially vulnerable skeletal sites such as the superolateral cortex of the femoral neck, where thinning is associated with increased fracture risk. Brief, high-impact exercise increases femoral neck bone density but the optimal frequency of such exercise and the location of bone accrual is unknown. This study thus examined (1) the effectiveness of different weekly frequencies of exercise on femoral neck BMD and (2) whether BMD change differed between hip sites using a high-impact, unilateral intervention. Methods Healthy premenopausal women were randomly assigned to exercise 0, 2, 4, or 7 days/week for 6 months. The exercise intervention incorporated 50 multidirectional hops on one randomly selected leg. BMD was measured by DXA at baseline and after 6 months of exercise. Changes in the exercise leg were compared between groups using ANCOVA, with change in the control leg and baseline BMD as covariates. RM-MANOVA was conducted to determine whether bone changes from exercise differed between hip sites. Results 61 women (age 33.6 ± 11.1 years) completed the intervention. Compliance amongst exercisers was 86.7 ± 10.6%. Peak ground reaction forces during exercise increased from 2.5 to 2.8 times body weight. The change in femoral neck BMD in the exercise limb (adjusted for change in the control limb and baseline BMD) differed between groups ( p = 0.015), being − 0.3% (− 1.2 to 0.6), 0.0% (− 1.0 to 1.0), 0.9% (− 0.1 to 2.0) and 1.8% (0.8 to 2.8) in those exercising 0, 2, 4 and 7 days per week, respectively. When BMD changes at upper neck, lower neck and trochanter were compared using RM-MANOVA, a significant exercise effect was observed ( p = 0.048), but this did not differ significantly between sites ( p = 0.439) despite greatest mean increases at the upper femoral neck. Conclusions Brief, daily hopping exercises increased femoral neck BMD in premenopausal women but less frequent exercise was not effective. Brief high-impact exercise may have a role in reducing hip fragility, but may need to be performed frequently for optimal response.

Muscle mass and function are related to bone mineral density (BMD) but associations with bone geometry and BMD at differently loaded hip regions are less well-known.To examine associations of muscle strength, maximal impact forces and body composition with hip bone density and geometry.In 88 sedentary, premenopausal women (32.6 +/- 8.5 years), fat-free mass (FFM), isometric knee extension strength (IKES), and peak landing ground reaction force (GRF) were measured. BMD at the proximal femur and sub-regions, section modulus (Z), and cross-sectional area (CSA) were estimated using dual X-ray absorptiometry.BMD at hip sites was significantly associated with body mass, IKES, GRF and FFM (r = 0.31-0.50) whilst Z and CSA were correlated with FFM (r = 0.67 and 0.62, respectively). In multivariate models, variables explaining most variance were body mass for lower neck and shaft BMD (25% and 17%, respectively), IKES for upper neck BMD (21%), GRF for trochanter (19%) and total hip BMD (18%) and FFM for femoral neck Z, CSA and BMD (54%, 38% and 20%, respectively).BMD at superolateral hip sites was most strongly related to muscle function and maximal impact forces, BMD at inferiomedial hip sites to body mass, and hip geometry to FFM.

Physical activity is one of the major non-pharmacological methods for increasing and maintaining bone mineral density (BMD) and geometry. As such, it has an important role in maintaining peak bone mass and strength, thus reducing the risk of future osteoporotic fracture. However, not all exercise is effective, so a prescription in terms of optimal type, intensity, frequency and duration is required. Studies using animal models suggest that loading that is high in magnitude, rapidly applied and novel is most effective, whilst duration is less important beyond a threshold number of cycles. In human subjects cross-sectional studies comparing different athletic populations suggest that those who participate in high- or odd-impact sports have higher BMD; whilst impact exercise, strength training and brief high-impact-jump training interventions increase BMD in premenopausal women. In order to further elucidate exercise recommendations to optimise bone health in this population, the usefulness of brief high-impact unilateral exercises has been evaluated. Brief hopping exercises were shown to be feasible for sedentary premenopausal women, producing ground-reaction forces as high as those from jumping. Regularly performing these hopping exercises over 6 months was found to increase femoral-neck BMD of the trained leg relative to the control leg. Unilateral high-impact exercise may therefore improve bone strength of the trained limb and provide a useful model for comparing exercise prescriptions to help define the most efficient and effective exercise recommendations for the bone health of premenopausal women.

Quantitative ultrasound (QUS) measures of bone predict fracture risk in older white women. South Asian women have low bone mineral density (BMD), perhaps related to smaller body size or vitamin D insufficiency, but it is unknown whether this is accompanied by lower QUS.The study compared QUS, BMD and vitamin D status between South Asian and white European women.Participants were 47 postmenopausal women (23 white European, 24 South Asian) aged 55-65 years. BMD was measured at the calcaneus and radius by dual X-ray absorptiometry. The QUS measurements were broadband ultrasound attenuation (BUA) at the calcaneus and speed of sound (SOS) at the calcaneus, radius and tibia. Serum 25-hydroxy vitamin D was determined in late summer.South Asian women had significantly lower serum 25-hydroxyvitamin D than white Europeans (13.0 +/- 5.1 versus 30.3 +/- 7.1 ng mL(-1); p0.001). Calcaneal BMD and BUA were 14% and 10% lower (p = 0.016 and 0.045), respectively, in South Asian women. Radial BMD, and SOS at all sites, did not differ significantly between groups.In this study, postmenopausal South Asian women living in the UK had a high prevalence of vitamin D insufficiency and lower calcaneal BMD than white European women, consistent with previous findings. Differences were detected in calcaneal BUA but not SOS. Further research is needed to evaluate fracture risk and its detection in South Asian women.

The optimisation of skeletal health during the life cycle is critical, especially if we are to reduce the continuing rise in osteoporosis -1 in 2 women and 1 in 5 men over the age of 50 years will suffer an osteoporotic fracture. The foundations of adult bone health are laid down in the early years; therefore, optimisation of bone health in the young is fundamental. Although genetics play a major role, accounting for 70-75% of bone strength, other lifestyle and nutrition factors are known to be highly influential. Calcium (Ca) and vitamin D play critical roles in bone mineralisation as well as generally being key nutrients in health. All living cells require Ca to survive, with the majority (99%) of Ca being found in bones and teeth and the remainder in soft tissues and body fluids. Vitamin D is the generic term for two molecules: ergocalciferol (vitamin D2) and cholecalciferol (vitamin D3). The former is derived by ultraviolet (UV) irradiation of ergosterol, which is distributed in plants and fungi. The latter is formed from the effect of UV irradiation on the skin. The principal role of vitamin D is to support the serum Ca concentration within narrow limits. Vitamin D is crucial for maximising gut absorption of calcium via vitamin D dependent Ca receptors. It is estimated that adequate vitamin D status increases Ca absorption to 30-40% of intake compared with only 10-15% absorption without adequate vitamin D. Intakes of Ca are a concern among certain groups of the population, for example a high proportion (>12%) of teenage boys and girls fail to meet the lower reference nutrient intake for Ca. For vitamin D, there are no dietary reference values for the age group 4-64 years as it is considered that UV exposure provides sufficient quantities of vitamin D, but there is now mounting evidence of widespread vitamin D insufficiency in the population. Weight-bearing physical activity is beneficial to the skeleton but clarification is needed of the exact type, intensity and duration required for optimal bone mass. The role of othermicronutrients on bone metabolism remains to be fully quantified. This review investigates the current evidence of the impact of dietary and lifestyle factors on bone health, with specific reference to children and adolescents and with a focus on vitamin D, Ca and weight-bearing exercise. © 2007 The Authors; Journal compilation © 2007 British Nutrition Foundation.

Regular exercisers have lower fracture risk, despite modest effects of exercise on bone mineral content (BMC). Exercise may produce localized cortical and trabecular bone changes that affect bone strength independently of BMC. We previously demonstrated that brief, daily unilateral hopping exercises increased femoral neck BMC in the exercise leg versus the control leg of older men. This study evaluated the effects of these exercises on cortical and trabecular bone and its 3D distribution across the proximal femur, using clinical CT. Fifty healthy men had pelvic CT scans before and after the exercise intervention. We used hip QCT analysis to quantify BMC in traditional regions of interest and estimate biomechanical variables. Cortical bone mapping localized cortical mass surface density and endocortical trabecular density changes across each proximal femur, which involved registration to a canonical proximal femur model. Following statistical parametric mapping, we visualized and quantified statistically significant changes of variables over time in both legs, and significant differences between legs. Thirty-four men aged mean (SD) 70 (4) years exercised for 12-months, attending 92% of prescribed sessions. In traditional regions of interest, cortical and trabecular BMC increased over time in both legs. Cortical BMC at the trochanter increased more in the exercise than control leg, whereas femoral neck buckling ratio declined more in the exercise than control leg. Across the entire proximal femur, cortical mass surface density increased significantly with exercise (2.7%; p < 0.001), with larger changes (> 6%) at anterior and posterior aspects of the femoral neck and anterior shaft. Endocortical trabecular density also increased (6.4%; p < 0.001), with localized changes of > 12% at the anterior femoral neck, trochanter, and inferior femoral head. Odd impact exercise increased cortical mass surface density and endocortical trabecular density, at regions that may be important to structural integrity. These exercise-induced changes were localized rather than being evenly distributed across the proximal femur.

Background: exercise can reduce osteoporotic fracture risk by strengthening bone or reducing fall risk. Falls prevention exercise programmes can reduce fall incidence, and also include strengthening exercises suggested to load bone, but there is little information as to whether these programmes influence bone mineral density (BMD) and strength. Objective: to evaluate the skeletal effects of home (Otago Exercise Programme, OEP) and group (Falls Exercise Management, FaME) falls prevention exercise programmes relative to usual care in older people. Methods: men and women aged over 65 years were recruited through primary care. They were randomised by practice to OEP, FaME or usual care. BMD, bone mineral content (BMC) and structural properties were measured in Nottingham site participants before and after the 24-week intervention. Results: participants were 319 men and women, aged mean(SD) 72(5) years. Ninety-two percentage of participants completed the trial. The OEP group completed 58(43) min/week of home exercise, while the FaME group completed 39(16) and 30(24) min/week of group and home exercise, respectively. Femoral neck BMD changes did not differ between treatment arms: mean (95% CI) effect sizes in OEP and FaME relative to usual care arm were −0.003(−0.011,0.005) and −0.002(−0.010,0.005) g cm−2, respectively; P = 0.44 and 0.53. There were no significant changes in BMD or BMC at other skeletal sites, or in structural parameters. Conclusions: falls prevention exercise programmes did not influence BMD in older people. To increase bone strength, programmes may require exercise that exerts higher strains on bone or longer duration.

This paper reports findings from three focus groups, involving 24 people, aged 65 to 79 years (20 women, four men), concerning their knowledge of safety on stairs. Findings indicate that older people use their stairs as and when necessary, but tend to avoid stair use when it becomes more difficult. The location of essential facilities in some homes (e.g. the lavatory), however, may lead to increased use of stairs for some. Despite recognition of hazardous behaviour, participants reported that they continued to engage in activities which may increase risk of falling, e.g. leaving objects on stairs and using stairs in the dark. Cleaning stairs presents problems in some cases due to difficulties with access or the need to use heavy and awkward equipment. Focus group participants recognised that medications and use of alcohol may increase the risk of falling, but it seems that individuals may not always appreciate when they personally are at increased risk. Most participants indicated they had given only limited thought to stair safety prior to the focus groups. Possibilities for prevention are reviewed, including modifications to the stair environment and equipment design, coupled with safety education, to raise awareness of risks and strategies for dealing with these.