-
1.
Hypertrophy and Explosive-Reactive Functioning in Sedentary Men After 10 Weeks of Whole-Body Vibration.
Ebing, J, Gast, U, Hauptmann, C, Felsenberg, D, Belavý, DL
Journal of strength and conditioning research. 2018;(1):27-36
Abstract
Ebing, J, Gast, U, Hauptmann, C, Felsenberg, D, and Belavý, DL. Hypertrophy and explosive-reactive functioning in sedentary men after 10 weeks of whole-body vibration. J Strength Cond Res 32(1): 27-36, 2018-The objective of this study was to determine the impact of vertical (Power-plate; POW) and side-alternating (Galileo; GAL) whole-body vibration exercise on muscle mass and lower-limb neuromuscular function. Forty-three sedentary male subjects (18-30 year) randomized into 3 groups underwent 2 upper-body exercise sessions per week for 10 weeks. Two groups of subjects underwent additional squat exercises on the GAL (N = 15) or POW (N = 14) devices. The third group was control. On magnetic resonance imaging, volume of the thigh muscles was measured. Countermovement jump, multiple one-leg hopping, drop jump, landing test, 15-m sprint, and grip strength were performed. Measurements were performed at baseline, and at 5 and 10 weeks. Significantly greater increases in vasti volume were seen in the GAL (+4.15%; p = 0.00076 vs. control) and POW (+4.81%; p = 0.0074 vs. control) groups than in the control group (-1.22%) at 10 weeks. The adductor magnus volume increased in the GAL (+2.24%; p = 0.00038 vs. baseline) and POW (+2.33%; p = 0.00038 vs. baseline) groups at 10 weeks, but this was not significantly different from the control (-0.67%; p = 0.54 vs. baseline). Hamstring volume decreased in GAL (-1.85%; p = 0.00038 vs. baseline) at 5 weeks with the reduction in the POW group at 5 weeks (-1.73%; p = 0.17 vs. baseline) not reaching significance. There were no significant differences between the POW and GAL groups (p ≥ 0.084) and no significant changes in neuromuscular performance. Twice weekly squat exercises with whole-body vibration, progressing from 3- to 5-minute time under tension, lead to thigh muscle hypertrophy but no improvements in explosive-reactive function.
-
2.
Impact of reduced skeletal muscle volume on clinical outcome after esophagectomy for esophageal cancer: A retrospective study.
Nagata, K, Tsujimoto, H, Nagata, H, Harada, M, Ito, N, Kanematsu, K, Nomura, S, Horiguchi, H, Hiraki, S, Hase, K, et al
Medicine. 2018;(30):e11450
-
-
Free full text
-
Abstract
The aim of the study was to clarify the impact of reduced skeletal muscle volume on the morbidity of patients who underwent esophagectomy for esophageal cancer.Malnutrition and reduced skeletal muscle volume, that is, presarcopenia, are reportedly associated with a high frequency of postoperative complications after esophagectomy. However, it remains unclear whether the reduction of skeletal muscle volume following esophagectomy may affect clinical outcomes including pneumonia occurred beyond the preoperative period.From February 2009 to June 2015, in 123 patients, we retrospectively evaluated the postoperative changes of the psoas muscle index (PI) on computed tomography and assessed their impact on the incidence of pneumonia after esophagectomy.There was a significant reduction in the PI 6 months after surgery compared to the preoperative value. The incidence of pneumonia as of 6 months after surgery was 23.6%, which was higher in patients of advanced age (P = .02), those with a lower body mass index (P = .02), and those with a greater reduction of PI during 6 months after surgery (P = .03). It was not associated with preoperative nutritional data, pulmonary function, operative procedure, and preoperative PI. Multivariate analysis demonstrated that age and postoperative PI reduction were independently associated with the incidence of pneumonia 6 months after surgery (hazard ratio [HR] = 2.92, 95% confidence interval [CI] 1.16-7.32, P = .02; HR = 3.25, 95% CI 1.15-9.15, P = .03, respectively). Patients with pneumonia 6 months after surgery had significantly poorer overall survival than those without pneumonia at that time.Postoperative reduction of skeletal muscle volume was independently associated with the occurrence of pneumonia beyond the preoperative period, which might indicate the importance of a postoperative nutritional support after perioperative period in esophageal cancer patients.
-
3.
Role of Oral Nutritional Supplements Enriched with β-Hydroxy-β-Methylbutyrate in Maintaining Muscle Function and Improving Clinical Outcomes in Various Clinical Settings.
Sanz-Paris, A, Camprubi-Robles, M, Lopez-Pedrosa, JM, Pereira, SL, Rueda, R, Ballesteros-Pomar, MD, Garcia Almeida, JM, Cruz-Jentoft, AJ
The journal of nutrition, health & aging. 2018;(6):664-675
-
-
Free full text
-
Abstract
Aging and disease-related malnutrition are well associated with loss of muscle mass and function. Muscle mass loss may lead to increased health complications and associated increase in health care costs, especially in hospitalized individuals. High protein oral nutritional supplements enriched with β-hydroxy-β-methylbutyrate (HP-ONS+HMB) have been suggested to provide benefits such as improving body composition, maintaining muscle mass and function and even decreasing mortality rates. The present review aimed to examine current evidence on the effect of HP-ONS+HMB on muscle-related clinical outcomes both in community and peri-hospitalization patients. Overall, current evidence suggests that therapeutic nutrition such as HP-ONS+HMB seems to be a promising tool to mitigate the decline in muscle mass and preserve muscle function, especially during hospital rehabilitation and recovery.
-
4.
Effects of leucine-enriched essential amino acid and whey protein bolus dosing upon skeletal muscle protein synthesis at rest and after exercise in older women.
Wilkinson, DJ, Bukhari, SSI, Phillips, BE, Limb, MC, Cegielski, J, Brook, MS, Rankin, D, Mitchell, WK, Kobayashi, H, Williams, JP, et al
Clinical nutrition (Edinburgh, Scotland). 2018;(6 Pt A):2011-2021
Abstract
BACKGROUND & AIMS Impaired anabolic responses to nutrition and exercise contribute to loss of skeletal muscle mass with ageing (sarcopenia). Here, we tested responses of muscle protein synthesis (MPS), in the under represented group of older women, to leucine-enriched essential amino acids (EAA) in comparison to a large bolus of whey protein (WP). METHODS Twenty-four older women (65 ± 1 y) received (N = 8/group) 1.5 g leucine-enriched EAA supplements (LEAA_1.5), 6 g LEAA (LEAA_6) in comparison to 40 g WP. A primed constant I.V infusion of 13C6-phenylalanine was used to determine MPS at baseline and in response to feeding (FED) and feeding-plus-exercise (FED-EX; 6 × 8 unilateral leg extensions; 75%1-RM). We quantified plasma insulin/AA concentrations, leg femoral blood flow (LBF)/muscle microvascular blood flow (MBF), and anabolic signalling via immunoblotting. RESULTS Plasma insulineamia and EAAemia were greater and more prolonged with WP than LEAA, although LEAA_6 peaked at similar levels to WP. Neither LEAA or WP modified LBF or MBF. FED increased MPS similarly in the LEAA_1.5, LEAA_6 and WP (P < 0.05) groups over 0-2 h, with MPS significantly higher than basal in the LEAA_6 and WP groups only over 0-4 h. However, FED-EX increased MPS similarly across all the groups from 0 to 4 h (P < 0.05). Only p-p70S6K1 increased with WP at 2 h in FED (P < 0.05), and at 2/4 h in FED-EX (P < 0.05). CONCLUSIONS In conclusion, LEAA_1.5, despite only providing 0.6 g of leucine, robustly (perhaps maximally) stimulated MPS, with negligible trophic advantage of greater doses of LEAA or even to 40 g WP. Highlighting that composition of EAA, in particular the presence of leucine rather than amount is most crucial for anabolism.
-
5.
Vitamin D and calcium supplementation, skeletal muscle strength and serum testosterone in young healthy adult males: Randomized control trial.
Saha, S, Goswami, R, Ramakrishnan, L, Vishnubhatla, S, Mahtab, S, Kar, P, Srinivasan, S, Singh, N, Singh, U
Clinical endocrinology. 2018;(2):217-226
Abstract
BACKGROUND Cholecalciferol and/or calcium supplementation might increase skeletal muscle strength and serum testosterone in young adult males. OBJECTIVE We performed a randomized control trial assessing the effect of cholecalciferol/calcium on skeletal muscle strength and serum testosterone in vitamin D deficient young males. DESIGN Two-by-two factorial RCT. SUBJECT AND INTERVENTION Two-hundred and twenty-eight young males were block-randomized to (i) double-placebo, (ii) calcium/placebo, (iii) cholecalciferol/placebo and (iv) cholecalciferol/calcium. Doses for cholecalciferol were 60 000 IU/wk for 8 weeks followed by 60 000 IU/fortnightly, and doses for elemental calcium were 500 mg/twice daily for 6 months. A total of 180 subjects completed the study protocol. Their ean age, body mass index and baseline 25(OH)D were 20.2 ± 2.2 years, 23.0 ± 3.6 kg/m2 and 21.5 ± 9.5 nmol/L, respectively. MEASUREMENTS Handgrip (primary outcome), pinch-grip strength, distance walked in 6 minutes, dyspnoea-score, quality of life by Short Form 36, serum 25(OH)D, 1,25(OH)2 D, iPTH, total testosterone and free androgen index (FAI). RESULTS After intervention, mean serum 25(OH)D was >75.0 nmol/L in cholecalciferol groups. However, the handgrip strength (29.7 ± 4.4, 29.3 ± 4.6, 30.6 ± 5.0 and 28.8 ± 4.3 kg, P = .28) was comparable in the 4 groups. Subgroups analysis among subjects with baseline serum 25OH)D < 25.0 and <12.0 nmol/L showed similar results. The mean serum testosterone decreased significantly at 6 months; however, delta change was similar in 4 groups. Change in handgrip strength and other outcomes was similar in 4 groups with and without adjustment for delta testosterone and FAI. CONCLUSIONS Six months of cholecalciferol/calcium supplementation had no significant effect on skeletal muscle strength and serum testosterone in young adult males.
-
6.
Intensive Care Nutrition and Post-Intensive Care Recovery.
Gunst, J, Van den Berghe, G
Critical care clinics. 2018;(4):573-583
Abstract
Intensive care unit (ICU)-acquired weakness frequently complicates critical illness, which prolongs intensive care dependency and causes long-term burden. Observational studies have suggested that prolonged underfeeding could aggravate ICU-acquired weakness and impair outcome. However, recent large randomized controlled trials have failed to show a benefit of early enhanced nutrition to critically ill patients. Moreover, early parenteral nutrition was even shown to increase ICU-acquired weakness and prolong organ failure and intensive care dependency, which may be explained by feeding-induced suppression of autophagy. Currently, the ideal timing of artificial nutrition for critically ill patients as well as the optimal dose and composition remain unclear.
-
7.
Effect of Carbohydrate Mouth Rinse on Performance after Prolonged Submaximal Cycling.
Jensen, M, Klimstra, M, Sporer, B, Stellingwerff, T
Medicine and science in sports and exercise. 2018;(5):1031-1038
Abstract
UNLABELLED Previous studies have shown improved shorter duration (∼1 h) performance with carbohydrate (CHO) mouth rinsing (WASH), especially in overnight fasted/non-fuelled subjects. PURPOSE To determine the effect of WASH on cycling time trial (TT) performance and muscle activity (EMG) after 2 h of submaximal cycling while receiving CHO (FED). METHODS In a double-blind, placebo-controlled crossover design, 10 well-trained males cyclists (V˙O2max: 65 mL·kg·min) completed two experimental trials. Each trial consisted of a standardized pretrial snack (2 h prior) followed by 120 min of steady-state (SS) cycling (∼60% V˙O2max) followed by an approximately 30-min TT, randomized as follows: 1) 30 g CHO·h during SS + WASH during TT (every 20% of TT) (FEDWASH); 2) 30 g CHO·h during SS + placebo (PLA) wash during TT (FEDPLA). RESULTS Although FEDWASH was not significantly different than FEDPLA (P = 0.51), there was a 1.7% (90% confidence interval, +6.4% to -3.2%; ES, 0.21) decrease in TT time (35 s) for FEDWASH compared with FEDPLA, with qualitative probabilities of a 60% positive and 23% trivial outcome. For EMG, soleus showed significant increase, whereas medial gastrocnemius showed significant decrease in muscle recruitment from the beginning 20% TT segment to the last 20% only in the FEDPLA condition, which coincided with a slower (P = 0.01) last 20% of the TT in FEDPLA versus FEDWASH. CONCLUSIONS Contrary to previous studies, this investigation utilized conditions of high ecological validity including a pretrial snack and CHO during SS. Significant changes in muscle recruitment and time over the last 20% of the TT, along with an average 1.7% improvement in TT time, suggest CHO mouth rinse helps maintain power output late in TT compared with placebo. Although marginal gains were achieved with a CHO mouth rinse (35 s), small performance effects can have significant outcomes in real-world competitions.
-
8.
Effect of Protein Supplementation During Diet-Induced Weight Loss on Muscle Mass and Strength: A Randomized Controlled Study.
Smith, GI, Commean, PK, Reeds, DN, Klein, S, Mittendorfer, B
Obesity (Silver Spring, Md.). 2018;(5):854-861
-
-
Free full text
-
Abstract
OBJECTIVE High protein (particularly leucine-rich whey protein) intake is recommended to mitigate the adverse effect of weight loss on muscle mass. The effectiveness of this approach is unknown. METHODS Seventy middle-aged (50-65 years old) postmenopausal women with obesity were randomized to (1) weight maintenance (WM), (2) weight loss and the recommended daily allowance for protein (0.8 g/kg/d) (WL group), or (3) weight loss plus whey protein supplementation (total protein: 1.2 g/kg/d) (WL-PS group). Thigh muscle volume and strength were assessed at baseline and after 5% and 10% weight loss in the weight-loss groups and after matched time periods (∼3 and 6 months, respectively) in the WM group. RESULTS A 5% weight loss caused a greater decrease in thigh muscle volume in the WL group than the WL-PS group (4.7% ± 0.7% vs. 2.8% ± 0.8%, respectively; P < 0.05). After 10% weight loss, there was no statistically significant difference in muscle mass loss in the two groups, and the total loss was small in both groups (5.5% ± 0.8% and 4.5% ± 0.7%, respectively). The dietary interventions did not affect muscle strength. CONCLUSIONS Whey protein supplementation during diet-induced weight loss does not have clinically important therapeutic effects on muscle mass or strength in middle-aged postmenopausal women with obesity.
-
9.
The Molecular Mechanisms and Prevention Principles of Muscle Atrophy in Aging.
Zhang, Y, Pan, X, Sun, Y, Geng, YJ, Yu, XY, Li, Y
Advances in experimental medicine and biology. 2018;:347-368
Abstract
Muscle atrophy in aging is characterized by progressive loss of muscle mass and function. Muscle mass is determined by the balance of synthesis and degradation of protein, which are regulated by several signaling pathways such as ubiquitin-proteasome system, autophagy-lysosome systems, oxidative stress, proinflammatory cytokines, hormones, and so on. Sufficient nutrition can enhance protein synthesis, while exercise can improve the quality of life in the elderly. This chapter will discuss the epidemiology, pathogenesis, as well as the current treatment for aging-induced muscular atrophy.
-
10.
Triggering Mechanisms for Motor Actions: The Effects of Expectation on Reaction Times to Intense Acoustic Stimuli.
Leow, LA, Uchida, A, Egberts, JL, Riek, S, Lipp, OV, Tresilian, J, Marinovic, W
Neuroscience. 2018;:226-235
Abstract
Motor actions can be released much sooner than normal when the go-signal is of very high intensity (>100 dBa). Although statistical evidence from individual studies has been mixed, it has been assumed that sternocleidomastoid (SCM) muscle activity could be used to distinguish between two neural circuits involved in movement triggering. We summarized meta-analytically the available evidence for this hypothesis, comparing the difference in premotor reaction time (RT) of actions where SCM activity was elicited (SCM+ trials) by loud acoustic stimuli against trials in which it was absent (SCM- trials). We found ten studies, all reporting comparisons between SCM+ and SCM- trials. Our mini meta-analysis showed that premotor RTs are faster in SCM+ than in SCM- trials, but the effect can be confounded by the variability of the foreperiods employed. We present experimental data showing that foreperiod predictability can induce differences in RT that would be of similar size to those attributed to the activation of different neurophysiological pathways to trigger prepared actions. We discuss plausible physiological mechanisms that would explain differences in premotor RTs between SCM+ and SCM- trials.