Cardiac autonomic function and its association with cardiometabolic disease risk factors in Black South African children.

OBJECTIVE: This study evaluated the associations between cardiac autonomic nervous system (ANS) activity and cardiometabolic disease (CMD) risk factors among black South African children. DESIGN: The participants included 34 black South African children (11.85 ±â€¯0.89 y). CMD risk factors included waist circumference (WC), hip circumference (HC), body mass index z-score (BMI z-score), blood pressure (SBP, DBP), total cholesterol (TC), high density lipoprotein cholesterol (HDL), low density lipoprotein cholesterol (LDL), fasting glucose (FG), fasting insulin (FINS), and vessel stiffness index (SI). Heart rate variability was used to quantify cardiac ANS activity. RESULTS: lnRMSSD, pNN50 and lnSD1 were inversely associated with FINS (r = -0.33, p = 0.05; r = -0.36, p = 0.03; r = -0.41, p = 0.01), WC (r = -0.45, p = 0.01; r = -0.39, p = 0.02; r = -0.45, p = 0.01), and HC (r = -0.41, p = 0.01; r = -0.36, p = 0.03; r = -0.43, p = 0.01). HDL was positively associated with lnRMSSD (r = 0.37; p = 0.03) and lnSD1 (r = 0.37; p = 0.03) while, LDL was negatively associated with HF (r = -0.41; p = 0.01). Regression analysis identified WC as the primary predictor for parasympathetic modulation in time domain (lnRMSSD: r2 = 0.21, p = 0.01; pNN50: r2 = 0.18, p = 0.01) and non-linear domain (lnSD1: r2 = 0.21, p = 0.01). CONCLUSION: Elevated resting parasympathetic activity in children is associated with lower CMD risk factors and an elevation in the protective HDL.

Short-Term High-Intensity Interval Training Is Superior to Moderate-Intensity Continuous Training in Improving Cardiac Autonomic Function in Children.

OBJECTIVES: This study aimed to investigate the impact of 3 isocaloric exercise programs on cardiac autonomic nervous system (ANS) functioning in children. METHODS: One hundred nine children (39% boys and 61% girls) aged 10-13 years (mean 11.07 ± 0.81) were conveniently assigned to 1 of 4 groups as follows: Moderate-intensity continuous training (MICT; n = 29) at 65-70% of the predicted maximum heart rate (MHR), High-intensity interval training (HIIT; n = 29) at > 80% of the predicted MHR, HIIT and MICT combined on alternate weeks (ALT; n = 27), and a control group (n = 24). Morning ANS activity was assessed via analysis of heart rate variability (HRV), with the patient in supine position for 10 min, before and after the exercise intervention. DATA ANALYSIS: A 2-way analysis of variance was used to evaluate the effects of training on all HRV parameters (p < 0.05/4 = 0.0125). RESULTS: After 5 weeks of training, significant improvements were observed for ln of the standard deviation of normal-to-normal intervals (p < 0.0001), ln of the root mean square of successive difference (p < 0.0001), and ln of standard deviation 1 (p < 0.0001), with superior results reported in the HIIT group (effect size [ES] = 2.22, 2.69, and 2.69) compared with the MICT (ES = 1.67, 1.75, and 1.75) and ALT (ES = 0.87, 1.06, and 1.06) groups, respectively. CONCLUSION: Short-term HIIT seems to induce superior alterations in cardiac ANS activity compared to MICT and ALT in children through enhanced vagal activity.

Do Short-Term Exercise Interventions Improve Cardiometabolic Risk Factors in Children?

OBJECTIVES: To explore the impact of short-term exercise of varying intensity on traditional risk factors for cardiometabolic disease. STUDY DESIGN: A total of 109 children (mean age, 11.1 ± 0.8 years) were conveniently assigned to 5 weeks of moderate-intensity continuous training (MICT; n = 29) set at 65%-70% of maximum heart rate, high-intensity interval training (HIIT; n = 29; >80% maximum heart rate), combined training (HIIT + MICT; n = 27), or no training (control; n = 24). Two-way ANOVA (group × time) was used to evaluate the effects of training on all cardiometabolic disease risk factors. Effect sizes were calculated to assess the magnitude of difference. RESULTS: MICT, HIIT, and HIIT + MICT were associated with significantly improved resting heart rate (effect size, -0.4, -1.1, and -1.1, respectively; P < .0001), fasting glucose (effect size, -0.6, -0.9, and -0.1, respectively; P = .0004), peak oxygen consumption (effect size, 0.5, 0.9, and 0.5, respectively; P < .0001), and c-reactive protein (effect size, -0.2, -1.0, and -0.5, respectively; P = .0016). HIIT + MICT was significantly associated with reduced waist circumference (-5.4%; P < .0001) and waist-to-hip ratio (-2.5%; P < .0002) compared with MICT (7.0% and 6.3%, respectively) and HIIT (-0.5% and -1.3%, respectively). CONCLUSION: Short-term HIIT and MICT interventions are useful for improving cardiometabolic health in children. HIIT + MICT may provide superior reductions in central obesity indicators.

Differing cytokine responses by ethnic groups to a bout of exercise-induced muscle damage: a preliminary report.

BACKGROUND: Strenuous exercise has been shown to alter immune and inflammatory responses potentially predisposing athletes to infection and injury. Ethnic disparities have been demonstrated in athletic performance and in the way individuals respond to exercise as well as in the predisposition towards certain diseases however, the information relating to immune and inflammatory responses to exercise between ethnic groups is still limited. The aim of this study was to investigate whether serum cytokine levels respond differently to eccentrically-biased exercise in African and Caucasian males. METHODS: Seven black and 8 white males (18-22 years), active but untrained, participated in the study. Participants performed a 60-minute downhill run on a treadmill (gradient -13.5%) at a speed eliciting 75% of their VO2peak on a level grade. Venipunctures were performed before, immediately after and then at 3, 6, 9, 12, 24 hours, and 1, 2 and 3 weeks afterwards. The following serum cytokine concentrations were quantified using the Bio-Plex suspension array system: IL-4, IL-6, IL-10, IL-1ra, IL-12p70, IFNγ, IL-7, IL-8, MCP-1, MIP-1ß, eotaxin, IP-10, IL-1ß, TNFα, GM-CSF, G-CSF, FGF basic and VEGF. RESULTS: Significant differences between the two groups were evident from 6 hours postexercise onwards with the African runners maintaining significantly higher relative cytokine concentrations. IL-6 serum concentrations of the African runners, for example, ranged from 8% to 55.1% higher than that of the Caucasian runners from 6 hours to 2 weeks postexercise (P<0.05). CONCLUSIONS: The study demonstrated that the cytokine response to a bout of downhill running differs between African and Caucasian runners indicating that ethnicity may play a role in exercise-induced immune and inflammatory responses.

Longitudinal patterns of change in eye-hand coordination in children aged 8-16 years.

Enhanced eye-hand coordination (EHC) is associated with greater participation in physical activity. No longitudinal studies have examined the change in throw-catch EHC from childhood to mid-adolescence. We investigated the development of EHC with an object control test from childhood to mid-adolescence in boys and girls. Evaluated at age 8, 10, 12 and 16 years, EHC was measured as the aggregate success rate of a throw and wall-rebound catch test. The test involved 40 attempts of progressive increasing difficulty, as determined by increased distances from a wall and transitions from two-handed to one-handed catches. Outcomes were treated as quasi-binomial and modelled by generalised linear mixed logistic regression analysis. EHC improved with age from childhood to mid-adolescence, although boys were more adept at each age (p<0.001). The patterns of change in EHC with increasing age varied according to the degree of difficulty of the task (p<0.001); throw and two-handed catch proficiency developing earlier than throw and one-handed catch in both sexes. Boys' EHC was better than girls' as early as age 8 years and male proficiency was maintained through to mid-adolescence. The proficiency of throw and two-handed catch rates developed faster than throw and one-handed catch rates for both sexes.

Exercise therapy for human immunodeficiency virus/AIDS patients: Guidelines for clinical exercise therapists.

Human immunodeficiency virus (HIV) has infected > 60 million people since its discovery and 30 million people have died since the pandemic began. Antiretroviral therapy has transformed HIV infection from an acute to a chronic disease, increasing life expectancy but also adding to the potential side effects associated with drug therapy and the comorbidity accompanying longevity. Exercise can play a valuable role in the management of HIV/AIDS patients by addressing various symptoms and improving their quality of life, but the optimum mode, intensity, frequency, and duration of exercise that take the different clinical stages of the disease into consideration are inadequately known. Searches of Medline, Embase, Science Citation Index, CINAHL database, HealthSTAR, PsycINFO, Cochrane Central Register of Controlled Trials (CENTRAL), Cochrane Database of Systematic Reviews, Physiotherapy Evidence Database (PEDro), and SPORTDiscus were conducted between 2000 and January 2014. Searches of published and unpublished abstracts were conducted, as well as a hand search of reference lists and tables of contents of relevant journals and books. Identified studies were reviewed for methodological quality. A total of 33 studies met the inclusion criteria. Most studies failed to indicate the optimum type (mode), intensity, frequency, and duration of aerobic and progressive resistive exercise prescribed to HIV-infected individuals in relation to the different clinical stages of the disease. The purpose of this review is to provide evidence-based recommendations after revision of exercise guidelines for HIV patients, by highlighting practical guidelines that clinical exercise therapists should consider when prescribing exercise for patients in different stages of the disease.

Salivary cortisol and α-amylase responses to repeated bouts of downhill running.

OBJECTIVES: To determine the hypothalamic-pituitary-adrenal (HPA) axis and sympathoadrenal (SA) system response to repeated bouts of downhill running. METHODS: Eleven active but untrained males (age: 19.7 ± 0.4 y; VO2peak 47.8 ± 3.6 ml/kg/min) performed two 60 min bouts of downhill running (-13.5% gradient), separated by 14 days, at a speed eliciting 75% of their VO2peak on a level grade. Saliva samples were collected before (baseline), after, and every hour for 12 h and every 24 h for 6 days after each run. Salivary cortisol and α-amylase levels were measured as markers of the HPA axis and SA response, respectively. Results were analyzed using repeated measures ANOVA (12 h period: 2 × 14; 24 h intervals 2 × 7, P ≤ 0.05) with Tukey post-hoc tests where appropriate. Paired samples t-tests were used to compare collapsed data vs. baseline measurements. RESULTS: There were no significant group × time interactions for cortisol or α-amylase for the hourly samples up to 12 h after each run, nor for the 24 h samples up to 6 days later. The 24 h samples for α-amylase showed a significant group effect between runs (Run 1: 69.77 ± 7.68 vs. Run 2: 92.19 ± 7.67 U/ml; P = 0.04). Significant time effects were measured for both cortisol (decreased 2 h to 12 h post-run) and α-amylase (elevated immediately after, 1 h and 2 h post-run) (P < 0.001). CONCLUSION: The 24 h period group effect for salivary α-amylase suggested an adaptation in the sympathoadrenal system that may alter the systemic inflammatory response to exercise-induced muscle damage but may also reflect enhanced mucosal immunity.

The effects of COREPOWER machine training versus home-based core training on golfers' physical fitness and sport performance.

The purpose of this study was to determine the effects of a 36 session COREPOWER machine training intervention and those of a 36 session home-based core training intervention programme on golfers' physical fitness and sport specific performance. It was hypothesised that both modalities will improve on golf related fitness aspects. Subjects comprised of experienced golfers and were randomly divided into a machine group (M: n = 51) and a home group (H: n = 50). The following variables were measured both pre- and post-intervention: lower back flexibility (sit & reach), muscle endurance (sit-ups and push-ups), muscle strength (wall-squats and back dynamometer), cardio-respiratory fitness (3 minute step-test), balance (Biodex Balance System), club head speed and carry distance (Flightscope). The Wilcoxon and Mann-Whitney signed-rank test was used to compare pre and post-intervention measurements within each group with significance set at p < 0.05. An ANCOVA analyses was also run as well as Pearson Product Moment correlations. Results portrayed that with the exception of cardiorespiratory fitness, all variables in both groups showed significant (p<0.05) improvement post intervention. Push-ups (p = 0.000; ↑17.03%; d = 0.92) and driver carry distance (p = 0.000; ↑30.30%; d = 0.40) showed the greatest percentage improvement post intervention within group M, while sit-ups (p = 0.000; ↑14.41%; d = 0.77) and push-ups (p = 0.000; ↑12.52%; d = 0.90) showed the greatest percentage improvement within group H. Lower back strength holds significant correlation to golf performance. Thus both modalities, the COREPOWER machine training and the home-based manual core training were equally effective in improving selected fitness components; however the machine was more effective in improving golf performance parameters. These observations can be applied to golfers in addition to their usual golfing activities as well as to other sport populations as this study formed an evidence base for core training.

Statin therapy, myopathy and exercise--a case report.

In a bid to reduce the morbidity and mortality associated with coronary artery disease, statin therapy has become a cornerstone treatment for patients with dyslipideamia. Statins, or HMG-CoA reductase inhibitors, are effective in blocking hepatic synthesis of cholesterol and are generally regarded as safe. Although rare, severe adverse side effects such as rhabdomyolysis have been reported, however, the more common complaint from patients is that related to myopathy. There is also mounting evidence that exercise may exacerbate these side effects, however the mechanisms are yet to be fully defined and there is controversy regarding the role that inflammation may play in the myopathy. This paper reports a patients experience during 6 months of simvastatin therapy and provides some insight into the white cell count (inflammation) following two bouts of moderate intensity exercise before and during statin therapy. It also highlights the need for rehabilitation practitioners to be aware of the adverse effects of statins in exercising patients.

Efficacy of home-based kinesthesia, balance & agility exercise training among persons with symptomatic knee osteoarthritis.

The purpose of this study was to determine the efficacy of a home-based kinesthesia, balance and agility (KBA) exercise program to improve symptoms among persons age ≥ 50 years with knee osteoarthritis (OA). Forty-four persons were randomly assigned to 8-weeks, 3 times per week KBA, resistance training (RT), KBA + RT, or Control. KBA utilized walking agility exercises and single-leg static and dynamic balancing. RT used elastic resistance bands for open chain lower extremity exercises. KBA + RT performed selected exercises from each technique. Control applied inert lotion daily. Outcomes included the OA specific WOMAC Index of Pain, Stiffness, and Physical Function (PF), community activity level, exercise self-efficacy, self-report knee stability, and 15m get up & go walk (GUG). Thirty-three participants [70.7 (SD 8.5) years] completed the trial. Analysis of variance comparing baseline, mid-point, and follow-up measures revealed significant (p < 0.05) improvements in WOMAC scores among KBA, RT, KBA + RT, and Control, with no differences between groups. However, Control WOMAC improvements peaked at mid-point, whereas improvement in the exercise conditions continued at 8-weeks. There were no significant changes in community activity level. Only Control improved exercise self-efficacy. Knee stability was improved in RT and Control. GUG improved in RT and KBA+RT. These results indicate that KBA, RT, or a combination of the two administered as home exercise programs are effective in improving symptoms and quality of life among persons with knee OA. Control results indicate a strong placebo effect in the short term. A combination of KBA and RT should be considered as part of the rehabilitation program, but KBA or RT alone may be appropriate for some patients. Studies with more statistical power are needed to confirm or refute these results. Patient presentation, preferences, costs, and convenience should be considered when choosing an exercise rehabilitation approach for persons with knee OA.

Knee Osteoarthritis and the Efficacy of Kinesthesia, Balance & Agility Exercise Training: A Pilot Study.

Kinesthesia, balance and agility (KBA) neuromuscular exercises are commonly used for rehabilitation of lower extremity injuries. KBA combined with strength training (ST) reportedly improves function among persons with knee osteoarthritis (OA), but independent effects of KBA are unknown. The purpose of this study was to determine the efficacy of KBA exercises, independent of ST, to improve function among persons with knee OA. Twenty participants (69.3, SD 11.4 y) were randomized to 8 weeks, 3-days per week, instructor-lead KBA or ST groups. Self-reported physical function (difficulty with daily living activities such as walking, bending, stair climbing, etc.) was measured at baseline and every two weeks. Community physical activity level, negative and positive outcome expectancies for exercise, self-reported knee stability, and timed 10-stair climb, 10-stair descent, and 'get up and go' 15 m walk were measured at baseline and follow-up. Physical function improved 59% (p = 0.02) with KBA and 40% (p = 0.02) with ST at 8 weeks. Community physical activity level improved only in KBA (p = 0.04); knee stability improved in both KBA (p = 0.04) and ST (p = 0.01). There were no significant between-group differences (p > 0.05). In conclusion, both interventions appear to improve function and knee stability among persons with symptomatic knee OA. As KBA has never been studied as an independent treatment program, our results indicate it is a promising stand-alone intervention worthy of further study.

Changes in serum cytokines after repeated bouts of downhill running.

The purpose of this study was to examine changes in serum cytokines after repeated bouts of aerobically biased eccentric exercise. Six untrained males ran down a -13.5% treadmill grade for 60 min on two occasions (RUN1 and RUN2) at a speed equal to 75% of their VO2 peak on a level grade; runs were spaced 14 d apart. Serum was collected before, after, and every hour for 12 h, and every 24 h for 6 d. Cytokines were assessed using 17 multiplex bead technology (Bio-Rad). Creatine kinase (CK) and delayed-onset muscle soreness (DOMS) were assessed before and 24-120 h after. Results were analyzed using a repeated measures analysis of variance (p