Evidence-Based Exercise Recommendations to Reduce Hepatic Fat Content in Youth- a Systematic Review and Meta-Analysis.
Prog Cardiovasc Dis. 2018 Feb 13;:
Authors: Medrano M, Cadenas-Sanchez C, Álvarez-Bueno C, Cavero-Redondo I, Ruiz JR, Ortega FB, Labayen I
The main purposes of this study were to elucidate the effects of supervised-exercise training (ET) interventions on hepatic fat content and on non-alcoholic fatty liver disease (NAFLD) prevalence in children and adolescents and to provide information about the optimal ET prescription (type, intensity, volume, and frequency) needed to reduce hepatic fat content in youths. Supervised-ET interventions performed in children and adolescents (6-19 years) that provided results of exercise effects on hepatic fat content or NAFLD prevalence were included. Supervised-exercise significantly reduced hepatic fat content compared to the control groups. Lifestyle interventions that included supervised-ET significantly reduced the prevalence of NAFLD. This systematic review and meta-analysis shows that supervised-ET could be an effective strategy in the management and prevention of NAFLD in children and adolescents. Both aerobic and resistance ET, at vigorous or moderate-to-vigorous intensities, with a volume ≥ 60 min/session and a frequency ≥ 3 sessions/week, aiming to improve cardiorespiratory fitness and muscular strength, had benefits on hepatic fat content reduction in youth. These data concur with the international recommendations of physical activity for health promotion in youth and may be useful when designing ET programs to improve and prevent hepatic steatosis in the pediatric population.
PMID: 29452135 [PubMed - as supplied by publisher]
Urban-Rural Differences in Aerobic Physical Activity, Muscle Strengthening Exercise, and Screen-Time Sedentary Behavior.
J Rural Health. 2018 Feb 16;:
Authors: Robertson MC, Song J, Taylor WC, Durand CP, Basen-Engquist KM
PURPOSE: Compared to their urban counterparts, US residents in rural settings face an increased risk of premature mortality and health problems that have been linked to insufficient physical activity (PA) levels. There is limited literature regarding urban-rural differences in adherence to national guidelines for all 3 PA-related behaviors.
METHODS: We investigated urban-rural differences in aerobic PA, leisure-time muscle strengthening PA, and leisure screen-time sedentary behavior in a combined data set of the 2011-2014 waves (N = 14,188) of the nationally representative National Cancer Institute's Health Information National Trends Survey.
FINDINGS: We found no evidence of a difference between large urban and rural residents' aerobic PA levels. The typical number of weekly bouts of leisure-time muscle strengthening PA was 25% lower for rural residents (incidence rate ratio [IRR] = 0.751, P < .001); this relationship was no longer statistically significant after controlling for potentially confounding covariates. In adjusted models, we found rural residents to engage in 6.6% less daily leisure screen-time sedentary behavior than their large urban counterparts (IRR = 0.934, P = .031).
CONCLUSIONS: Taken together with previous literature, these results suggest that rural residents may engage in comparable levels of total PA, but less leisure-time PA, than their urban counterparts.
PMID: 29451333 [PubMed - as supplied by publisher]
Shoulder and arm muscle activity during elastic band exercises performed in a hospital bed.
Phys Sportsmed. 2018 Feb 16;:
Authors: Skals S, Vinstrup J, Sundstrup E, Jakobsen MD, Andersen CH, Andersen LL
OBJECTIVE: Muscle atrophy is a common side-effect of bed rest during hospitalization. However, resistance training may minimize or even prevent these complications. Therefore, we evaluated the efficiency of four upper-body elastic resistance exercises that could be performed while lying or sitting in a hospital bed.
METHODS: Twenty-two healthy subjects performed three repetitions of each exercise in a supine and seated position with a perceived intensity of 3 (low) and 8 (high) on the Borg CR10 Scale. Surface electromyography was collected from 12 shoulder and arm muscles (e.g. trapezius, deltoideus and biceps brachii), and normalized to a maximal voluntary isometric contraction (nEMG).
RESULTS: During all exercises performed at high intensity, moderate (>40%) to high (>60%) levels of nEMG were found for the majority of the analysed muscles, e.g. deltoideus (from 37% to 69%, median 57.5%), trapezius (from 43% to 66%, median 51%) and infraspinatus (from 54% to 66%, median 59%), with the exception of pectoralis major (from 29% to 47%, median 39.5%) and latissimus dorsi (from 15% to 22%, median 18.5%). No significant differences were found between the supine and seated positions for any of the exercises.
CONCLUSION: This study showed that high levels of shoulder and arm muscle activity can be achieved while lying or sitting in a hospital bed using appropriate exercises with elastic bands. The data presented here can be used by physiotherapists as a guideline for selecting suitable and effective strengthening exercises during in-hospital rehabilitation to counteract bed-rest related muscle atrophy in the upper body.
PMID: 29451065 [PubMed - as supplied by publisher]
Acute effects of blood flow restriction on exercise-induced free radical production in young and healthy subjects.
Free Radic Res. 2018 Feb 16;:1-171
Authors: Centner C, Zdzieblik D, Dressler P, Fink B, Gollhofer A, König D
The main purpose of this study was to investigate the acute local and systemic effects of low-load resistance exercise (30% 1RM) with partial vascular occlusion on exercise-induced free radical production and to compare these effects with other established training methods. Fifteen young and healthy males (25 ± 3 years) performed the following four sessions in a counterbalanced order on separate days: low-load resistance exercise (LI: 30% 1RM), low-load resistance exercise with blood flow restriction (LIBR: 30% 1RM), high-load resistance exercise (HI: 80% 1RM) and an additional session without exercise but blood flow restriction only (BR). Blood samples were obtained 15 minutes prior to and immediately after exercise sessions from the right index finger and first toe. To analyze concentrations of reactive oxygen species (ROS), electron paramagnetic resonance (EPR) spectroscopy was used. Additionally, mitochondrial ROS production was measured by adding inhibitors of electron transport chain complex III. There was an increased systemic ROS generation after the LIBR session from 0.838 ± 0.096-0.901 ± 0.095 µmol/l/min. However, no local or systemic time × condition interaction was detected for ROS production. Regarding mitochondrial ROS production, results were not different between the conditions. Although the low-load resistance exercise session with partial vascular occlusion elicited systemic increases of ROS production, no significant changes were seen on a local level. We assume that this ROS concentration might not be high enough to induce cellular damage but is rather involved in muscle remodulation. However, this needs to be confirmed by future research.
PMID: 29448855 [PubMed - as supplied by publisher]
Electromyographic comparison of conventional machine strength training versus bodyweight exercises in patients with chronic stroke.
Top Stroke Rehabil. 2017 May;24(4):242-249
Authors: Vinstrup J, Calatayud J, Jakobsen MD, Sundstrup E, Jay K, Brandt M, Zeeman P, Jørgensen JR, Andersen LL
OBJECTIVE: To investigate whether bodyweight exercises can induce comparable levels of muscle activity as conventional machine exercises in chronic stroke patients.
METHODS: Eighteen patients performed three repetitions of bilateral- and unilateral machine leg press and the bodyweight exercises chair rise and hip thrust. Surface electromyography (EMG) was recorded from 10 lower extremity muscles and normalized to maximal EMG (nEMG) of the non-paretic leg.
RESULTS: For the paretic leg, the bodyweight exercises showed comparable levels of nEMG in 6 out of 10 muscles compared with the bilateral leg press. Vastus lateralis nEMG was higher during bilateral leg press compared with hip thrust (38% [95% CI 33-42] vs. 10% [95% CI 6-15], p < 0.0001) and chair rise (38% [95% CI 33-42] vs. 27% [95% CI 22-32], p < 0.0001). Vastus medialis nEMG was higher during bilateral leg press compared with hip thrust (34% [95%CI 27-40] vs. 8% [95% CI 2-15], p < 0.0001). Unilateral leg press showed higher nEMG compared with bilateral leg press in biceps femoris (28% [95% CI 23-34] vs. 19% [95% CI 13-24], p = 0.0009), gluteus maximus (32% [95% CI 23-41] vs. 25% [95% CI 16-34], p < 0.05), and vastus medialis (42% [95% CI 36-48] vs. 34% [95% CI 27-40], p = 0.0013).
DISCUSSION: In patients with chronic stroke, bodyweight exercises activate the majority of the lower limb muscles to comparable levels as bilateral leg press performed in machine. In addition, unilateral leg press was superior to the bilateral leg press and both bodyweight exercises.
PMID: 28056670 [PubMed - indexed for MEDLINE]