Muscle Damage following Maximal Eccentric Knee Extensions in Males and Females

Aim: To investigate whether there is a sex difference in exercise induced muscle damage. Materials and Method: Vastus Lateralis and patella tendon properties were measured in males and females using ultrasonography. During maximal voluntary eccentric knee extensions (12 reps x 6 sets), Vastus Lateralis fascicle lengthening and maximal voluntary eccentric knee extensions torque were recorded every 10° of knee joint angle (20–90°). Isometric torque, Creatine Kinase and muscle soreness were measured pre, post, 48, 96 and 168 hours post damage as markers of exercise induced muscle damage. Results: Patella tendon stiffness and Vastus Lateralis fascicle lengthening were significantly higher in males compared to females (p0.05). Creatine Kinase levels post exercise induced muscle damage were higher in males compared to females (p<0.05), and remained higher when maximal voluntary eccentric knee extension torque, relative to estimated quadriceps anatomical cross sectional area, was taken as a covariate (p<0.05). Conclusion: Based on isometric torque loss, there is no sex difference in exercise induced muscle damage. The higher Creatine Kinase in males could not be explained by differences in maximal voluntary eccentric knee extension torque, Vastus Lateralis fascicle lengthening and patella tendon stiffness. Further research is required to understand the significant sex differences in Creatine Kinase levels following exercise induced muscle damage

Joint angle-specific neuromuscular time course of recovery after isometric resistance exercise at shorter and longer muscle lengths

Resistance training at longer muscle lengths induces greater muscle hypertrophy and different neuromuscular functional adaptations than training at shorter muscle lengths. However, the acute time course of recovery of neuromuscular characteristics after resistance exercise at shorter and longer muscle lengths in the quadriceps has never been described. Eight healthy young participants (4 M, 4 F) were randomly assigned to perform four sets of eight maximal isometric contractions at shorter (SL; 50° knee flexion) or longer (LL; 90° knee flexion) muscle lengths in a crossover fashion. During exercise, peak torque (PT), muscle activity [electromyogram (EMG)], and internal muscle forces were assessed. PT and EMG at shorter (PT50, EMG50) and longer (PT90, EMG90) muscle lengths, creatine kinase (CK), and muscle soreness were measured at baseline, immediately after exercise (Post), after 24 h (24 h), and after 48 h (48 h). During exercise, EMG (P ¼ 0.002) and internal muscle forces (P ¼ 0.017) were greater in LL than in SL. During recovery, there was a main effect of exercise angle, with PT50 (P ¼ 0.002), PT90 (P ¼ 0.016), and EMG50 (P ¼ 0.002) all significantly reduced to a greater degree in LL compared with SL. CK and muscle soreness increased after resistance exercise, but there were no differences between SL and LL. The present results suggest that if the preceding isometric resistance exercise is performed at longer muscle lengths, function and muscle activity at shorter and longer muscle lengths are inhibited to a larger degree in the subsequent recovery period. This information can be used by practitioners to manipulate exercise prescription. NEW & NOTEWORTHY: Despite the established long-term benefits of training at longer muscle lengths for muscle size and strength, acutely performing resistance exercise at longer muscle lengths may require a longer time course of neuromuscular recovery compared with performing resistance exercises at shorter muscle lengths. Furthermore, there appear to be different joint angle-specific recovery profiles, depending on the muscle length of the preceding exercise

Segregating the Distinct Effects of Sedentary Behavior and Physical Activity on Older Adults' Cardiovascular Profile: Part 2-Isotemporal Substitution Approach.

The aim of the study was to provide an isotemporal substitution model to predict how changes in physical behavior may affect the cardiovascular parameters (CVPs) of older adults. Methods: Participants wore a thigh-mounted accelerometer for 7 days. Phenotype of the carotid, brachial, and popliteal artery was conducted using ultrasound. Isotemporal substitution was used to simulate the degree to which replacing 1 hour of physical behavior with another would affect CVP. Results: Substitution of sedentary behavior with Standing and sporadic moderate- to vigorous-intensity physical activity (MVPA accumulated in bouts <10 min) would reduce resting heart rate [−6.20 beats per minute (−12.1 to −0.22) and −3.72 beats per minute (−7.01 to −0.44), respectively]. Substitution of sedentary behavior with light-intensity physical activity would reduce carotid artery diameter [−0.54 mm (−1.00 to −0.07)]. Substitution of Standing with sporadic MVPA would increase popliteal artery diameter [1.31 mm (0.11 to 2.51)]. Conclusions: Our modeling suggests that an accumulation of MVPA bouts that are shorter than the recommended 10-minute minimum may still improve CVP, with lower intensity physical activity also influencing CVP. Our findings are a promising avenue for lifestyle interventions in older adults to reduce the aging effects on CVP for those who cannot engage or sustain sufficient MVPA

Impact of Circulating Triglycerides Concentration on Atherosclerotic Disease Status in Middle-Aged Saudi Arabian Dwellers

A number of food micronutrients are reported to influence markers of cardio-metabolic health. There is an expectation that there may be an optimal endocrine profile, with triglycerides as a key factor, which may help minimise atherosclerotic disease and associated risk factors. This study involved 84 participants aged (mean ± SD) 48.2 ± 8.3 years from both sexes segregated into n = 30 controls, n = 25 at-risk, and n = 29 diagnosed with atherosclerosis, including 20 participants using statins. Atherosclerosis status and risk factors were assessed using a combination of clinical records, C-reactive protein (CRP), blood glucose (FBG), lipids profiles, vascular structural and functional characteristics (including carotid-radial pulse wave velocity (CR-PWV), central systolic blood pressure (C-SBP), peripheral systolic blood pressure (P-SBP), peripheral diastolic blood pressure (P-DBP), carotid intima-media thickness (IMT), and carotid artery inter-adventitial diameter (IAD)). There was a significant difference in triglycerides (TG) levels between the clinical groups (p < 0.05) and between the users and non-users of statin (p < 0.001). Significant associations were distinguished between TG and CRP, FBG, high-density lipoprotein (HDL), C-SBP, P-SBP, P-DBP, CR-PWV, heart rate (HR), and body weight in the pooled sample (p < 0.05). In non-users of statin, TG was associated with C-SBP, P-SBP, P-DBP, and HR. In sub-clinical groups, TG was also associated with most of the blood markers. After controlling for statin use, composite z-score analysis revealed 48%, 2%, and 0% differences in in vivo vascular phenotype between high and low TG subgroups in controls, at-risk, and diagnosed atherosclerosis groups, respectively. Thus, TG levels seem to be good indicators for incidence and risk factors of atherosclerosis

Impaired glucose tolerance in adults with Duchenne and Becker muscular dystrophy

The aim of this study was to determine the response to an oral glucose tolerance test (OGTT) in adult males with Becker muscular dystrophy (BMD) and Duchenne muscular dystrophy (DMD), and to investigate whether body composition contributes to any variance in the glucose response. Twenty-eight adult males with dystrophinopathy (BMD, n = 13; DMD, n = 15) and 12 non-dystrophic controls, ingested 75 g oral anhydrous glucose solution. Fingertip capillary samples were assessed for glucose at 30-min intervals over 2-h post glucose ingestion. Fat free mass relative to body mass (FFM/BM) and body fat (BF%) was assessed using bioelectrical impedance. Vastus lateralis muscle anatomical cross sectional area (VL ACSA) was measured using B-mode ultrasonography. Blood glucose was higher in MD groups than control at 60, 90 and 120 min post ingestion of glucose. Compared to controls, FFM/BM and VL ACSA were lower in MD groups compared to controls (p < 0.001). Glucose tolerance values at 120 min were correlated with FFM/BM and BF% in the BMD group only. Our results suggest that glucose tolerance is impaired following OGTT in adult males with BMD and DMD. It is recommended that adults with BMD and DMD undertake routine glucose tolerance assessments to allow early detection of impaired glucose tolerance

Developing an aerobic exercise intervention for patients with psoriasis to support lifestyle behaviour change and improve health outcomes

BACKGROUND: Patients with psoriasis do not exercise to the extent recommended for cardiovascular health, which may contribute to the increased risk of cardiovascular disease (CVD) and metabolic syndrome observed in this patient group. We previously identified that patients with psoriasis have significant disease-specific barriers to exercise. Others have reported that individuals with psoriasis develop higher heart rates and systolic blood pressure during bouts of exercise, followed by a slower recovery than healthy control subjects. AIMS: We hypothesized that a bespoke, evidenced-based, exercise programme could be developed for patients with psoriasis. METHODS: We convened a multidisciplinary Working Group comprising key stakeholders, including patients with psoriasis, along with sports scientists and clinicians, to develop the programme. RESULTS: To allow for different levels of fitness, lifestyle and motivation a 10-week intervention comprising two group walking sessions per week each of 1 h duration [led by a sports scientist (RS)] was designed using the Mapometer website. Walking distance was validated by a Walkmeter application, which uses global positioning system technology. The volume of exercise per session was calculated so that participants could incrementally progress to heart-healthy levels of exercise over the course of the programme. Maps of 20 unique walking routes were developed. A GENEactiv Original accelerometer and Newfeel Onwalk 900 pedometer were selected as wearable devices. CONCLUSION: We developed an exercise programme which specifically removed barriers to exercise for those with psoriasis, in partnership with patients. Regular exercise may offer significant health benefits for patients with psoriasis, including reduced CVD risk and increased psychosocial functioning, and this programme merits further investigation

Prevalence and association of single nucleotide polymorphisms with sarcopenia in older women depends on definition

© 2020, The Author(s). The prevalence of sarcopenia depends on the definition used. There are, however, consistent sarcopenic characteristics, including a low muscle mass and muscle strength. Few studies have investigated the relationship between sarcopenia and genotype. A cross-sectional study was conducted with 307 community-dwelling ≥60-year-old women in South Cheshire, UK. Handgrip strength was assessed with a handgrip dynamometer and skeletal muscle mass was estimated using bioelectrical impedance. DNA was extracted from saliva (∼38%) or blood (∼62%) and 24 single-nucleotide polymorphisms (SNPs) were genotyped. Three established sarcopenia definitions - %Skeletal Muscle Mass (%SMM), Skeletal Muscle Mass Index (SMI) and European Working Group on Sarcopenia in Older People (EWGSOP) - were used to assess sarcopenia prevalence. Binary logistic regression with age as covariate was used to identify SNPs associated with sarcopenia. The prevalence of sarcopenia was: %SMM 14.7%, SMI 60.6% and EWGSOP 1.3%. Four SNPs were associated with the %SMM and SMI definitions of sarcopenia; FTO rs9939609, ESR1 rs4870044, NOS3 rs1799983 and TRHR rs7832552. The first three were associated with the %SMM definition, and TRHR rs7832552 with the SMI definition, but none were common to both sarcopenia definitions. The gene variants associated with sarcopenia may help proper counselling and interventions to prevent individuals from developing sarcopenia

A review of the prevalence of sedentarism in older adults, its physiology/health impact and non-exercise mobility counter-measures

This literature review focuses on aspects of sedentary behaviour (SB) in elderly. Since it has been identified as a distinct health risk, independent of physical activity, SB is demonstrating as being a significant issue. This is particularly true for an ageing population as evidence shows that older adults (aged ≥65 years) are the most sedentary age group (on average 8.5-9.6 hours daily sitting time). Accurate SB assessment is important for understanding this habitual behaviour and its impact. However, SB measurement is challenging, regardless of the method used. Although negative associations of SB in elderly have been reported for several health outcomes, evidence is inconclusive, apart from the evidence on the adverse SB effect on the all-cause mortality rate. Generally, strategies have been proposed to counteract SB, of which breaking prolonged sedentary bouts with at least light-intensity physical activity seems to be the most promising. Overall, further research in elderly is required to increase the evidence and to either support or refute the current findings. Moreover, further research will help to develop informed SB guidelines for an optimal strategy to counteract SB and its health effects in older adults

The Effects of Displacing Sedentary Behavior With Two Distinct Patterns of Light Activity on Health Outcomes in Older Adults (Implications for COVID-19 Quarantine)

Rationale: The COVID-19 pandemic is limiting outdoor and community-based activities, especially for older adults owing to the requirement for self-isolation, potentially increasing prolonged sedentary behavior (SB). Given a poor tolerance for intense exercise, SB displacement with light intensity physical activity (LIPA) is a promising health enhancing alternative. Therefore, the aims of this study were to investigate the effects of two different types of SB displacement on health outcomes in older adults and any differential impact of associated LIPA pattern. Method: 28 older women (age: 73 ± 5 years, height: 1.60 ± 0.07 m, weight: 67 ± 10 kg, and BMI: 26.1 ± 3.6 kg/m2) underwent overnight fasted dual energy x-ray absorptiometry (DEXA) imaging, blood sampling, and functional assessments before being randomly allocated to one of two groups: (1) single continuous bout of 45–50 min LIPA daily (n = 14); or (2) SB fragmentation (SBF; ~48 min LIPA daily, 2 min LIPA for every 30 min of SB; n = 14). Compliance was systematically monitored using tri-axial accelerometery. All measures were taken at weeks 0 and 8. Results: Physical behavior significantly altered (decreased SB/increased LIPA; p < 0.05) and to a similar extent in both groups. We observed a significant reduction in serum triglycerides [p = 0.045, effect size (ɳp2) = 0.15; SBF: −0.26 ± 0.77 mmol/L, LIPA: −0.26 ± 0.51 mmol/L], improved 30 s sit-to-stand (STS) count (p = 0.002, ɳp2 = 0.32, 2 ± 3 STS) and speed (p = 0.009, ɳp2 = 0.35, −10 ± 33%), as well as increased average handgrip strength (p = 0.001, ɳp2 = 0.45, 6 ± 12%), and gait speed (p = 0.005, ɳp2 = 0.27, 0.09 ± 0.16 m/s) in both groups. Interestingly, SBF caused a greater increase in peak handgrip strength (8 ± 14%), compared to LIPA (2 ± 10%; p = 0.04, ɳp2 = 0.38). Conclusion: SB displacement induced significant improvements in fasting triglycerides, gait speed, as-well as STS endurance/speed in older women. Frequent vs. continuous SB displacement also caused greater increases in handgrip strength. While both SB displacement protocols display promise as efficacious home-based interventions for self-isolating older adults, our results would suggest a physical functioning advantage of the SBF protocol for certain outcomes