ACTN3 R577X polymorphism related to sarcopenia and physical fitness in active older women.

BACKGROUND: As the population is getting older, physical activity promotion becomes a good strategy to increase quality of life in the elderly; but genetic condition also plays an important role. The purpose of this study was to examine the association of the ACTN3 R577X polymorphism with physical fitness and muscle mass in physically active older women. METHODS: A cross-sectional study was performed with two groups of older women who practiced physical exercise regularly. The first cohort comprised 164 women (age 69.7 ± 3.2 years) and the second cohort 131 women (age 78.5 ± 3.0 years). The main outcome measures were anthropometric measures with assessment of sarcopenia and sarcopenic obesity, self-reported physical activity EXERNET questionnaire (EEPAQ), evaluation of physical fitness (muscle strength and flexibility test), and ACTN3 genotyping. RESULTS: Women above 75 years old with allele R presented a higher risk of experiencing sarcopenia compared to ACTNR XX homozygous women (odds ratio 0.356, 95% confidence interval 0.139-0.915, p = 0.026). Furthermore, statistically significant differences were found in the chair stand test (p = 0.04), as well as in the sit and reach test (p = 0.01), with better results for women below 75 years old with the ACTN3 XX genotype. CONCLUSIONS: Sarcopenia and physical fitness show differences based on the ACTN3 R577X genotype in active older women.

Does fitness attenuate the relationship between changes in sitting time and health-related quality of life over time in community-dwelling older adults? Evidence from the EXERNET multicenter longitudinal study.

OBJECTIVE: To assess the relationship between fitness levels and components, sitting time and health-related quality of life (HRQoL), over time among community-dwelling older adults. METHODS: Three different sitting trajectories were calculated: (i) no change; (ii) decrease; and (iii) increase in ST, between baseline and follow-up. Fitness was assessed using the aerobic capacity, upper and lower limb strength, and total fitness. Participants were classified into higher (75th percentile or above) or lower (below 75th percentile) fitness levels, using the fitness tests. HRQoL scores at follow-up were compared to the three different sitting time trajectories within and across both the higher and the lower fitness groups for each of the three fitness indexes. RESULTS: Greater HRQoL scores were observed in those participants that decreased their ST as compared with those increasing their sitting time over time for participants classified in the lower end of their aerobic capacity or total fitness index. No differences were detected in HRQoL scores in people classified in the higher fitness level group for any of the fitness indexes. Participants that increased or did not change their sitting time and who were classified in the higher fitness end of aerobic capacity and total fitness index self-reported higher HRQoL scores when compared with those in the lower fitness end. CONCLUSION: Increased sitting time over time is associated with poorer HRQoL in older adults. Higher fitness levels could help attenuate the negative impact of sitting over time.

Non-osteogenic muscle hypertrophy in children with McArdle disease.

INTRODUCTION: McArdle disease is an inborn disorder of muscle glycogen metabolism that produces exercise intolerance, and has been recently associated with low values ​​of lean mass (LM) and bone mineral content (BMC) and density (BMD) in affected adults. Here we aimed to study whether this bone health problem begins in childhood. METHODS: Forty children and adolescents were evaluated: 10 McArdle disease and 30 control children (mean age of both groups, 13 ± 2y). Body composition was evaluated by dual-energy X-ray absorptiometry and creatine kinase (CK) levels were determined in the patients as an estimate of muscle damage. RESULTS: Legs bone mass was significantly lower in patients than in controls (-36% for BMC and -22% for BMD). Moreover, patients had significantly higher LM values in the legs than controls, whereas no difference was found for fat mass. CK levels were positively associated with LM in McArdle patients. A correlation was found between LM and BMD variables in the control group but not in McArdle patients. CONCLUSION: We have identified a 'non-osteogenic muscle hypertrophy' in children with McArdle disease. This phenomenon warrants special attention since low osteogenesis at an early age predicts a high risk for osteoporosis later in life.

Sleep disturbance, obesity, physical fitness and quality of life in older women: EXERNET study group.

OBJECTIVES: To investigate the association between physical fitness, obesity, health related quality of life (HRQoL) and sleep disturbance in 463 community-dwelling older Spanish women (66-91 years of age). STUDY DESIGN: Cross-sectional study. METHOD: Sleep disturbance was assessed with the Jenkins Sleep Scale. Active and sedentary behaviors were recorded by standardized questionnaires. HRQoL was assessed with the EuroQoL-5D. Anthropometric measurements were obtained using standardized techniques. Body fat was measured using bioelectrical impedance. Physical fitness was evaluated by a set of eight tests. RESULTS: Sleep disturbance was reported by 45.1% of women, being associated with higher body mass index (p < 0.05) and waist circumference (p < 0.01). Presence of insomnia was inversely associated with physical fitness. Women in the upper tertile of fitness index had 92.0% lower risk of sleep disturbance as compared to the lower tertile (p = 0.08), while women in the highest tertile of upper body strength had 76.4% lower risk of sleep disturbance as compared to the lower tertile (p < 0.05). Women without sleep disturbance showed better HRQoL. CONCLUSION: Sleep disturbance was associated with central obesity, lower physical fitness and reduced HRQoL. Interventions involving weight management and improvement of physical fitness may contribute to better sleep quality in older women.

Demographic history and adaptation account for clock gene diversity in humans.

Circadian clocks give rise to daily oscillations in behavior and physiological functions that often anticipate upcoming environmental changes generated by the Earth rotation. In model organisms a relationship exists between several genes affecting the circadian rhythms and latitude. We investigated the allele distributions at 116 000 single-nucleotide polymorphisms (SNPs) of 25 human clock and clock-related genes from the 1000Genomes Project, and at a reference data set of putatively neutral polymorphisms. The global genetic structure at the clock genes did not differ from that observed at the reference data set. We then tested for evidence of local adaptation searching for FST outliers under both an island and a hierarchical model, and for significant association between allele frequencies and environmental variables by a Bayesian approach. A total of 230 SNPs in 23 genes, or 84 SNPs in 19 genes, depending on the significance thresholds chosen, showed signs of local adaptation, whereas a maximum of 190 SNPs in 23 genes had significant covariance with one or more environmental variables. Only two SNPs from two genes (NPAS2 and AANAT) exhibit both elevated population differentiation and covariance with at least one environmental variable. We then checked whether the SNPs emerging from these analyses fall within a set of candidate SNPs associated with different chronotypes or sleep disorders. Correlation of five such SNPs with environmental variables supports a selective role of latitude or photoperiod, but certainly not a major one.

Fragility fracture risk and skeletal muscle function.

Low-intensity fractures are closely related with age-related musculoskeletal disorders, including osteoporosis, muscle dysfunction and sarcopenia, age-related chronic diseases, and pharmacological treatments. During the last years, a huge amount of information and recommendations has been released in relation to bone metabolism and mineral content. Muscle dysfunction and sarcopenia are highly prevalent during the second half of life, especially in older subjects. The development of sarcopenia may be slowed through healthy lifestyle changes, which include adequate dietary protein, vitamin D and mineral intakes, and regular physical activity. Prevention of falls should be integral, including correction in major involved factors in order to reduce fragility fracture, improve quality of life and appropriately focus clinical and economic resources. Therefore, to obtain better results a global approach is needed to prevent age-related fractures in frail patients that is not only centered on bone metabolism and antiresorptive drugs.

Variations of Weight of Prostate Gland in Different Age Groups of Bangladeshi Cadaver.

Now a days, benign prostatic hyperplasia and carcinoma of the prostate are the most common disorders in men. A cross sectional descriptive study was conducted in Department of Anatomy, Mymensingh Medical College, Mymensingh to find out the difference in weight of the prostate gland of Bangladeshi people in relation to age. The present study was performed on 67 postmortem human prostate gland collected from the morgue in the Department of Forensic Medicine, Mymensingh Medical College by non random purposive sampling technique. The specimens were collected from Bangladeshi cadaver of age ranging from 10 to 80 years. All the specimens were grouped into three categories - Group A (upto 18 years), Group B (19 to 45 years) and Group C (above 45 years) according to age. Dissection was performed according to standard autopsy techniques. The weight of the prostate gland were measured and recorded. The mean weight of the prostate gland was 10.13gm in Group A, 17.27gm in Group B and 22.50gm in Group C. Variance analysis shows that mean differences of weight of the prostate were highly significant among all age groups. The weight of prostate gland was found to increase with increased age. For statistical analysis, differences between age groups were analyzed by using students unpaired 't' test. The present study will help to increase the information pool on the weight of prostate gland of Bangladeshi people.

Mitochondrial coupling and capacity of oxidative phosphorylation in skeletal muscle of Inuit and Caucasians in the arctic winter.

During evolution, mitochondrial DNA haplogroups of arctic populations may have been selected for lower coupling of mitochondrial respiration to ATP production in favor of higher heat production. We show that mitochondrial coupling in skeletal muscle of traditional and westernized Inuit habituating northern Greenland is identical to Danes of western Europe haplogroups. Biochemical coupling efficiency was preserved across variations in diet, muscle fiber type, and uncoupling protein-3 content. Mitochondrial phenotype displayed plasticity in relation to lifestyle and environment. Untrained Inuit and Danes had identical capacities to oxidize fat substrate in arm muscle, which increased in Danes during the 42 days of acclimation to exercise, approaching the higher level of the Inuit hunters. A common pattern emerges of mitochondrial acclimatization and evolutionary adaptation in humans at high latitude and high altitude where economy of locomotion may be optimized by preservation of biochemical coupling efficiency at modest mitochondrial density, when submaximum performance is uncoupled from VO2max and maximum capacities of oxidative phosphorylation.

Maintained peak leg and pulmonary VO2 despite substantial reduction in muscle mitochondrial capacity.

We recently reported the circulatory and muscle oxidative capacities of the arm after prolonged low-intensity skiing in the arctic (Boushel et al., 2014). In the present study, leg VO2 was measured by the Fick method during leg cycling while muscle mitochondrial capacity was examined on a biopsy of the vastus lateralis in healthy volunteers (7 male, 2 female) before and after 42 days of skiing at 60% HR max. Peak pulmonary VO2 (3.52 ± 0.18 L.min(-1) pre vs 3.52 ± 0.19 post) and VO2 across the leg (2.8 ± 0.4L.min(-1) pre vs 3.0 ± 0.2 post) were unchanged after the ski journey. Peak leg O2 delivery (3.6 ± 0.2 L.min(-1) pre vs 3.8 ± 0.4 post), O2 extraction (82 ± 1% pre vs 83 ± 1 post), and muscle capillaries per mm(2) (576 ± 17 pre vs 612 ± 28 post) were also unchanged; however, leg muscle mitochondrial OXPHOS capacity was reduced (90 ± 3 pmol.sec(-1) .mg(-1) pre vs 70 ± 2 post, P < 0.05) as was citrate synthase activity (40 ± 3 µmol.min(-1) .g(-1) pre vs 34 ± 3 vs P < 0.05). These findings indicate that peak muscle VO2 can be sustained with a substantial reduction in mitochondrial OXPHOS capacity. This is achieved at a similar O2 delivery and a higher relative ADP-stimulated mitochondrial respiration at a higher mitochondrial p50. These findings support the concept that muscle mitochondrial respiration is submaximal at VO2max , and that mitochondrial volume can be downregulated by chronic energy demand.

Outcome of Percutaneous Tenotomy in the Management of Congenital Talipes Equino Varus by Ponseti Method.

Congenital talipes equino varus (CTEV) is a common complex congenital anomaly affecting approximately 1 per 900 live births in Bangladesh. Current trends in the treatment of idiopathic clubfoot have shifted from extensive surgical release to more conservative techniques. The Ponseti method that includes manipulation, serial casting, percutaneous tenotomy and bracing has recently become very popular for the management of CTEV with reported excellent outcomes. The purpose of this study was to evaluate the outcomes of Percutaneous Tenotomy in the treatment of equinus deformity of idiopathic clubfoot. Between June 2012 and November 2013 we treated 47 feet in 34 children by the Ponseti method. The standard protocol described by Ponseti was used. Percutaneous tenotomy of the Achilles tendon was performed under local anaesthesia in the outpatient department of Dhaka Medical College Hospital. The Pirani score was used for assessment and mean follow up time was 12 months. The compliance of percutaneous tenotomy among the 47 feet was recorded and 40(85.1%) were good, 4(8.5%) were fair and 3(6.4%) were poor. The rating of final outcome of percutaneous tenotomy after one year follow-up periods among 47 feet, 36(76.6%) were good, 11(23.4%) were fair and zero (0%) were poor. This study permits to conclude the percutaneous tenotomy in Ponseti method as a safe, effective outdoor procedure to correct the residual equinus deformity of club foot after serial casting.

Time-course effects of aerobic interval training and detraining in patients with metabolic syndrome.

BACKGROUND AND AIMS: Exercise training can improve health of patients with metabolic syndrome (MetS). However, which MetS factors are most responsive to exercise training remains unclear. We studied the time-course of changes in MetS factors in response to training and detraining. METHODS AND RESULTS: Forty eight MetS patients (52 ± 8.8 yrs old; 33 ± 4 BMI) underwent 4 months (3 days/week) of supervised aerobic interval training (AIT) program. After 1 month of training, there were progressive increases in high density lipoprotein cholesterol (HDL-c) and reductions in waist circumference and blood pressure (12 ± 3, -3.9 ± 0.4, and -12 ± 1%, respectively after 4 months; all P < 0.05). However, fasting plasma concentration of triglycerides and glucose were not reduced by training. Insulin sensitivity (HOMA), cardiorespiratory fitness (VO2peak) and exercise maximal fat oxidation (FOMAx) also progressively improved with training (-17 ± 5; 21 ± 2 and 31 ± 8%, respectively, after 4 months; all P < 0.05). Vastus lateralis samples from seven subjects revealed that mitochondrial O2 flux was markedly increased with training (71 ± 11%) due to increased mitochondrial content. After 1 month of detraining, the training-induced improvements in waist circumference and blood pressure were maintained. HDL-c and VO2peak returned to the values found after 1-2 months of training while HOMA and FOMAx returned to pre-training values. CONCLUSIONS: The health related variables most responsive to aerobic interval training in MetS patients are waist circumference, blood pressure and the muscle and systemic adaptations to consume oxygen and fat. However, the latter reverse with detraining while blood pressure and waist circumference are persistent to one month of detraining.

Influence of hard vs. soft ground surfaces on bone accretion in prepubertal footballers.

Information regarding osteogenic effects of physical activity performed on different playing surfaces is scarce. A total of 42 children (9.2±0.2 years, Tanner stages I-II) participated in this study. 14 were playing on artificial turf soft ground (SG), 14 on a natural non-grass hard ground (HG) and 14 were assigned to the sedentary control group (C). Whole body and hip scans (dual energy X-ray absorptiometry), anthropometric variables (weight and height) and physical fitness (VO2max) were determined in all participants. Bone mineral content (BMC) values were higher in the SG group compared to the C group at the legs (209.75±5.11 g vs. 187.42±5.14 g, respectively), pelvis (122.72±4.27 g vs. 98.58±4.29 g respectively) and whole-body level (1 126.1±22.81 g vs. 1 035.34±22.92 g, respectively). The hard ground (HG) group also showed higher values in the majority of BMC variables compared to the C group. Additionally, bone mineral density (BMD) was significantly higher at all sites of the hip in both active groups compared to control (P<0.05). No differences between HG and SG were found. In summary, similar bone mass accretion is obtained by prepubescent footballers independently of the surface on which they practice football.

The Medium-Term Changes in Health-Related Behaviours among Spanish Older People Lifestyles during Covid-19 Lockdown.

OBJECTIVES: The aim was to evaluate general changes and investigate the association between diet quality, physical activity (PA), and sedentary time (ST) during COVID-19 lockdown and the subsequent 7-month changes in health-related behaviours and lifestyles in older people. PARTICIPANTS: 1092 participants (67-97y) from two Spanish cohorts were included. DESIGN: Telephone-based questionaries were used to evaluate health-related behaviours and lifestyle. Multinomial logistic regression analyses with diet quality, PA, and ST during lockdown as predictors for health-related behaviours changes post-lockdown were applied. RESULTS: Diet quality, PA, and ST significantly improved post-lockdown, while physical component score of the SF-12 worsened. Participants with a low diet quality during lockdown had higher worsening of post-lockdown ST and anxiety; whereas those with high diet quality showed less likelihood of remaining abstainers, worsening weight, and improving PA. Lower ST was associated with a higher likelihood of remaining abstainers, and worsening weight and improving social contact; nevertheless, higher ST was linked to improvement in sleep quality. Lower PA was more likely to decrease alcohol consumption, while higher PA showed the opposite. However, PA was more likely to be associated to remain abstainers. CONCLUSIONS: Despite improvements in lifestyle after lockdown, it had health consequences for older people. Particularly, lower ST during lockdown seemed to provide the most medium-term remarkable lifestyle improvements.

Normal mitochondrial function and increased fat oxidation capacity in leg and arm muscles in obese humans.

AIM/HYPOTHESIS: The aim of this study was to investigate mitochondrial function, fibre-type distribution and substrate oxidation during exercise in arm and leg muscles in male postobese (PO), obese (O) and age- and body mass index (BMI)-matched control (C) subjects. The hypothesis of the study was that fat oxidation during exercise might be differentially preserved in leg and arm muscles after weight loss. METHODS: Indirect calorimetry was used to calculate fat and carbohydrate oxidation during both progressive arm-cranking and leg-cycling exercises. Muscle biopsy samples were obtained from musculus deltoideus (m. deltoideus) and m. vastus lateralis muscles. Fibre-type composition, enzyme activity and O(2) flux capacity of saponin-permeabilized muscle fibres were measured, the latter by high-resolution respirometry. RESULTS: During the graded exercise tests, peak fat oxidation during leg cycling and the relative workload at which it occurred (FatMax) were higher in PO and O than in C. During arm cranking, peak fat oxidation was higher in O than in C, and FatMax was higher in O than in PO and C. Similar fibre-type composition was found between groups. Plasma adiponectin was higher in PO than in C and O, and plasma leptin was higher in O than in PO and C. CONCLUSIONS: In O subjects, maximal fat oxidation during exercise and the eliciting relative exercise intensity are increased. This is associated with higher intramuscular triglyceride levels and higher resting non esterified fatty acid (NEFA) concentrations, but not with differences in fibre-type composition, mitochondrial function or muscle enzyme levels compared with Cs. In PO subjects, the changes in fat oxidation are preserved during leg, but not during arm, exercise.

How important is current physical fitness for future quality of life? Results from an 8-year longitudinal study on older adults.

INTRODUCTION: A vast amount of research has focused on the effects of physical fitness (PF) on mortality, with little research evaluating the effects of PF on future expected health related quality of life (HRQoL). AIM: To evaluate how current PF influences future HRQoL measured in a prospective 8-year study in older adults. METHODS: A total of 617 (157 males) older adults (>65y) participated in the study. PF was assessed with the EXERNET battery in 2008-2009 (baseline) and 2016-2017 (follow-up). HRQoL was assessed using the EQ-5D-3L questionnaire in both evaluations. PF tertiles were developed from baseline PF variables: FIT (highest PF values), REGULAR and UNFIT (lowest PF values) taking into account age and sex. Follow-up HRQoL values were compared to sex and age-specific expected values. Logistic regressions were performed to test differences between PF tertiles regarding future expected quality of life. Linear regressions were developed to test whether baseline PF could predict future HRQoL scores. RESULTS: The FIT group showed higher probabilities of an improved HRQoL when compared to the UNFIT group. All PF variables seemed to be important at some point of the study except upper extremities flexibility. Aerobic endurance was the variable that showed to be significant for most of the HRQoL predictions. CONCLUSION: PF influences future HRQoL in older adults who accordingly should try to remain fit to maintain an increased age-adjusted HRQoL.

Leptin receptor 170 kDa (OB-R170) protein expression is reduced in obese human skeletal muscle: a potential mechanism of leptin resistance.

To examine whether obesity-associated leptin resistance could be due to down-regulation of leptin receptors (OB-Rs) and/or up-regulation of suppressor of cytokine signalling 3 (SOCS3) and protein tyrosine phosphatase 1B (PTP1B) in skeletal muscle, which blunt janus kinase 2-dependent leptin signalling and signal transducer and activator of transcription 3 (STAT3) phosphorylation and reduce AMP-activated protein kinase (AMPK) and acetyl-coenzyme A carboxylase (ACC) phosphorylation. Deltoid and vastus lateralis muscle biopsies were obtained from 20 men: 10 non-obese control subjects (mean +/- s.d. age, 31 +/- 5 years; height, 184 +/- 9 cm; weight, 91 +/- 13 kg; and percentage body fat, 24.8 +/- 5.8%) and 10 obese (age, 30 +/- 7 years; height, 184 +/- 8 cm; weight, 115 +/- 8 kg; and percentage body fat, 34.9 +/- 5.1%). Skeletal muscle OB-R170 (OB-R long isoform) protein expression was 28 and 25% lower (both P < 0.05) in arm and leg muscles, respectively, of obese men compared with control subjects. In normal-weight subjects, SOCS3 protein expression, and STAT3, AMPKalpha and ACCbeta phosphorylation, were similar in the deltoid and vastus lateralis muscles. In obese subjects, the deltoid muscle had a greater amount of leptin receptors than the vastus lateralis, whilst SOCS3 protein expression was increased and basal STAT3, AMPKalpha and ACCbeta phosphorylation levels were reduced in the vastus lateralis compared with the deltoid muscle (all P < 0.05). In summary, skeletal muscle leptin receptors and leptin signalling are reduced in obesity, particularly in the leg muscles.

Health-related physical fitness in children and adolescents with Down syndrome and response to training.

Physical fitness is related to health at all ages. Information about physical fitness in the Down syndrome (DS) population, however, is scarce, especially when we consider children and adolescents. A review of the current data available on this topic would be both timely and important as it would serve as a starting point to stimulate new research perspectives. The data we reviewed from the literature showed a general trend toward lower values of physical fitness parameters and worse body composition variables in children and adolescents with DS compared with the population without intellectual disability (ID) or even with the population with ID without DS. Notably, children and adolescents with DS have been described as less active or overprotected; however, these factors may not be the cause of their poor physical fitness. Many of the training programs carried out in children and adolescents with DS did not yield the desired responses, and the reasons are still unknown. The purpose of this review is to summarize the current available literature on health-related physical fitness in children and adolescents with DS, and the effect of training on these variables. From the literature available, it is clear that more data on this population are necessary.

Physical fitness and obesity are associated in a dose-dependent manner in children.

AIMS: To analyze the relationships between physical fitness, lifestyle-related factors, and obesity in a large population of children. METHODS: A cross-sectional study design including children aged 7-12 years (n = 715) was used. Adiposity measures included subcutaneous fat mass (SFM) and body mass index (BMI). Physical fitness and lifestyle-related factors were also assessed. RESULTS: When SFM was used as the adiposity variable, the odds ratios (OR) for being obese in boys in the highest quartiles of fitness were 0.02 (95% CI 0.02-0.13) for aerobic fitness, 0.04 (95% CI 0.01-0.16) for dynamic force, and 5.32 (95% CI 1.82-15.58) for running speed (in which quartile 1 corresponds to the best performance) compared with boys in the lowest quartile. In girls, the OR for those in the highest quartiles of fitness were 0.04 (95% CI 0.01-0.14), 0.16 (95% CI 0.05-0.51), and 5.24 (95% CI 1.74-15.75), respectively, showing a significant dose-response relationship between fitness and fatness in both sexes (p for trend <0.001). CONCLUSIONS: An inverse relationship between physical fitness levels and the risk of being overweight/obese was found inasmuch as children with higher physical fitness seem to be more protected against fat mass accumulation than their counterparts with lower fitness levels.

Associations between Physical Fitness, Bone Mass, and Structure in Older People.

The main aim was to analyse the associations between several physical fitness variables and bone parameters in a sample of elderly people. 129 participants (94 females and 35 males, 76.2 ± 5.4 y) from the EXERNET cohort of Zaragoza (Spain) were included in the study. Physical fitness was assessed using the Senior Fitness Test Battery. Peripheral quantitative computed tomography (pQCT) at the tibia and dual-energy X-ray absorptiometry (DXA) at the hip and lumbar spine were used to assess bone and muscle parameters. Partial correlations were used to describe the associations between fitness and bone parameters. A stepwise regression analysis was used to determine the influence of fitness variables on bone parameters. In males, significant correlations were found between lower body strength and agility with bone total mineral density (Tt.BMD) (r = 0.41 and -0.50) and cortical thickness (r = 0.40 and -0.50, respectively) and walking speed with total and cortical density (r = -0.41 and -0.40, respectively), all measured at tibia (all p < 0.05). Regarding DXA, neck areal bone mineral density (aBMD) correlated with flexibility (r = -0.37) and walking speed (r = 0.39) and Ward's triangle with walking speed (r = 0.39). Agility predicted Tt.BMD and cortical thickness (r 2 change = 24.8% and 23.0%), while walking speed predicted cortical bone mineral density (r 2 change = 19.5%) (all p < 0.05). Females showed correlations between balance and total hip aBMD (r = 0.27) and trochanter aBMD (r = 0.25). Balance predicted trochanter (r 2 change = 4.2%) and total hip aBMD (r 2 change = 4.9%) (both p < 0.05). In conclusion, bone mass in elderly males seems to be more influenced by physical fitness than in females, being agility and walking speed the variables showing greater associations. Other variables should be taken into account in females for future research.

Are substrate use during exercise and mitochondrial respiratory capacity decreased in arm and leg muscle in type 2 diabetes?

AIM/HYPOTHESIS: The aim of the study was to investigate mitochondrial function, fibre type distribution and substrate oxidation in arm and leg muscle during exercise in patients with type 2 diabetes and in obese and lean controls. METHODS: Indirect calorimetry was used to calculate fat and carbohydrate oxidation during both progressive arm-cranking and leg-cycling exercises. Muscle biopsies from arm and leg were obtained. Fibre type, as well as O(2) flux capacity of saponin-permeabilised muscle fibres were measured, the latter by high resolution respirometry, in patients with type 2 diabetes, age- and BMI-matched obese controls, and age-matched lean controls. RESULTS: Fat oxidation was similar in the groups during either arm or leg exercise. During leg exercise at higher intensities, but not during arm exercise, carbohydrate oxidation was lower in patients with type 2 diabetes compared with the other groups. In patients with type 2 diabetes, ADP-stimulated state 3 respiration per mg muscle with parallel electron input from complex I+II was lower in m. vastus lateralis compared with obese and lean controls, whereas no differences between groups were present in m. deltoideus. A higher percentage of type IIX fibres was seen in m. vastus lateralis in patients with type 2 diabetes compared with obese and lean controls, whereas no difference was found in the deltoid muscle. CONCLUSIONS/INTERPRETATION: This study demonstrates similar O(2) flux capacity, fibre type distribution and carbohydrate oxidation in arm muscle in the groups despite the presence of attenuated values in leg muscle in patients with type 2 diabetes compared with obese and lean controls.