-
1.
Passive heat therapy in sedentary humans increases skeletal muscle capillarization and eNOS content but not mitochondrial density or GLUT4 content.
Hesketh, K, Shepherd, SO, Strauss, JA, Low, DA, Cooper, RJ, Wagenmakers, AJM, Cocks, M
American journal of physiology. Heart and circulatory physiology. 2019;(1):H114-H123
Abstract
Passive heat therapy (PHT) has been proposed as an alternative intervention to moderate-intensity continuous training (MICT) in individuals who are unable or unwilling to exercise. This study aimed to make the first comparison of the effect of PHT and MICT on 1) skeletal muscle capillarization and endothelial-specific endothelial nitric oxide synthase (eNOS) content and 2) mitochondrial density, glucose transporter 4 (GLUT4), and intramuscular triglyceride (IMTG) content. Twenty young sedentary males (21 ± 1 yr, body mass index 25 ± 1 kg/m2) were allocated to either 6 wk of PHT (n = 10; 40-50 min at 40°C in a heat chamber, 3×/wk) or MICT (n = 10; time-matched cycling at ~65% V̇o2peak). Muscle biopsies were taken from the vastus lateralis muscle before and after training. Immunofluorescence microscopy was used to assess changes in skeletal muscle mitochondrial density (mitochondrial marker cytochrome c oxidase subunit 4), GLUT4, and IMTG content, capillarization, and endothelial-specific eNOS content. V̇o2peak and whole body insulin sensitivity were also assessed. PHT and MICT both increased capillary density (PHT 21%; MICT 12%), capillary-fiber perimeter exchange index (PHT 15%; MICT 12%) (P < 0.05), and endothelial-specific eNOS content (PHT 8%; MICT 12%) (P < 0.05). However, unlike MICT (mitochondrial density 40%; GLUT4 14%; IMTG content 70%) (P < 0.05), PHT did not increase mitochondrial density (11%, P = 0.443), GLUT4 (7%, P = 0.217), or IMTG content (1%, P = 0.957). Both interventions improved aerobic capacity (PHT 5%; MICT 7%) and whole body insulin sensitivity (PHT 15%; MICT 36%) (P < 0.05). Six-week PHT in young sedentary males increases skeletal muscle capillarization and eNOS content to a similar extent as MICT; however, unlike MICT, PHT does not affect skeletal muscle mitochondrial density, GLUT4, or IMTG content. NEW & NOTEWORTHY The effect of 6-wk passive heat therapy (PHT) compared with moderate-intensity continuous training (MICT) was investigated in young sedentary males. PHT induced similar increases in skeletal muscle capillarization and endothelial-specific endothelial nitric oxide synthase content to MICT. Unlike MICT, PHT did not improve skeletal muscle mitochondrial density, glucose transporter 4, or intramuscular triglyceride content. These microvascular adaptations were paralleled by improvements in V̇o2peak and insulin sensitivity, suggesting that microvascular adaptations may contribute to functional improvements following PHT.
-
2.
Active versus local vibration warm-up effects on knee extensors stiffness and neuromuscular performance of healthy young males.
Souron, R, Zambelli, A, Espeit, L, Besson, T, Cochrane, DJ, Lapole, T
Journal of science and medicine in sport. 2019;(2):206-211
Abstract
OBJECTIVES To compare the effects of local-vibration and active warm-up on knee extensors muscle stiffness and neuromuscular performance. DESIGN Experimental crossover study. METHODS Thirteen participants performed three 15-min warm-up protocols of control (CON), active (ACT) and local-vibration (LV) in separate testing session. Passive stiffness of vastus lateralis (VL) and vastus medialis (VM) by shear wave elastography and neuromuscular performance were assessed before and 2-min after each condition. RESULTS A decrease in muscle stiffness was reported after ACT for VL (-16.0±6.6%; p<0.001) and VM (-10.2±8.7%; p=0.03) while no changes were reported after CON (p=0.46 and p=0.34 for VL and VM, respectively) and LV (p=0.07 and p=0.46 for VL and VM, respectively). Maximal jump performances increased during squat (+8.5±6.6%; p<0.001) and countermovement jump (+5.2±5.8%; p<0.001) after ACT while no changes were reported after CON and LV during squat (p=0.16 and p=0.81, respectively) and countermovement jump (p=0.18 and p=0.31, respectively). We further report that each condition was ineffective to inducing changes in maximal voluntary isometric contraction force (p=0.18), rate of force development (p=0.92), twitch parameters (p>0.05) as well as central modulations as reported by the unchanged voluntary activation level (p=0.24) and maximal electromyography (EMG) recorded from the VL (p=0.44). CONCLUSIONS The active warm-up acutely reduced muscle stiffness and increased muscle performance during maximal dynamic tasks. With regard to LV, further studies are required to determine optimal parameters (frequency, amplitude, duration) to significantly increase muscle performance.
-
3.
Effects of elastic taping, non-elastic taping and static stretching on recovery after intensive eccentric exercise.
Boobphachart, D, Manimmanakorn, N, Manimmanakorn, A, Thuwakum, W, Hamlin, MJ
Research in sports medicine (Print). 2017;(2):181-190
Abstract
The purpose of this study was to compare the effect of elastic tape (Kinesio tape) to placebo tape or static stretching on delayed onset muscle soreness. Fifty-one untrained female healthy volunteers were randomly assigned into three groups (n = 17/group), elastic tape, placebo tape and stretching group. Muscle soreness was induced by 4 sets of 25 maximal isokinetic (60°.s-1) eccentric contractions of dominant quadriceps on an isokinetic dynamometer. Compared with placebo tape, the elastic tape participants had less muscle soreness at 72 h post-exercise (p = 0.01). The elastic tape also increased isometric strength at 72 h post-exercise compared with the placebo (p = 0.03) and stretching group (p = 0.02). However, there was little effect between groups for changes in thigh circumference, jumping, pressure pain threshold, rate of perceived exertion, creatine kinase activity and joint motion. Elastic taping increased muscle strength recovery and reduced muscle soreness after intensive exercise.
-
4.
Impact of adrenaline and metabolic stress on exercise-induced intracellular signaling and PGC-1α mRNA response in human skeletal muscle.
Brandt, N, Gunnarsson, TP, Hostrup, M, Tybirk, J, Nybo, L, Pilegaard, H, Bangsbo, J
Physiological reports. 2016;(14)
Abstract
This study tested the hypothesis that elevated plasma adrenaline or metabolic stress enhances exercise-induced PGC-1α mRNA and intracellular signaling in human muscle. Trained (VO2-max: 53.8 ± 1.8 mL min(-1) kg(-1)) male subjects completed four different exercise protocols (work load of the legs was matched): C - cycling at 171 ± 6 W for 60 min (control); A - cycling at 171 ± 6 W for 60 min, with addition of intermittent arm exercise (98 ± 4 W). DS - cycling at 171 ± 6 W interspersed by 30 sec sprints (513 ± 19 W) every 10 min (distributed sprints); and CS - cycling at 171 ± 6 W for 40 min followed by 20 min of six 30 sec sprints (clustered sprints). Sprints were followed by 3:24 min:sec at 111 ± 4 W. A biopsy was obtained from m. vastus lateralis at rest and immediately, and 2 and 5 h after exercise. Muscle PGC-1α mRNA content was elevated (P < 0.05) three- to sixfold 2 h after exercise relative to rest in C, A, and DS, with no differences between protocols. AMPK and p38 phosphorylation was higher (P < 0.05) immediately after exercise than at rest in all protocols, and 1.3- to 2-fold higher (P < 0.05) in CS than in the other protocols. CREB phosphorylation was higher (P < 0.05) 2 and 5 h after exercise than at rest in all protocols, and higher (P < 0.05) in DS than CS 2 h after exercise. This suggests that neither plasma adrenaline nor muscle metabolic stress determines the magnitude of PGC-1α mRNA response in human muscle. Furthermore, higher exercise-induced changes in AMPK, p38, and CREB phosphorylation are not associated with differences in the PGC-1α mRNA response.
-
5.
Guanidinoacetic acid versus creatine for improved brain and muscle creatine levels: a superiority pilot trial in healthy men.
Ostojic, SM, Ostojic, J, Drid, P, Vranes, M
Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme. 2016;(9):1005-7
Abstract
In this randomized, double-blind, crossover trial, we evaluated whether 4-week supplementation with guanidinoacetic acid (GAA) is superior to creatine in facilitating creatine levels in healthy men (n = 5). GAA (3.0 g/day) resulted in a more powerful rise (up to 16.2%) in tissue creatine levels in vastus medialis muscle, middle-cerebellar peduncle, and paracentral grey matter, as compared with creatine (P < 0.05). These results indicate that GAA as a preferred alternative to creatine for improved bioenergetics in energy-demanding tissues.
-
6.
Effect of protein overfeeding on energy expenditure measured in a metabolic chamber.
Bray, GA, Redman, LM, de Jonge, L, Covington, J, Rood, J, Brock, C, Mancuso, S, Martin, CK, Smith, SR
The American journal of clinical nutrition. 2015;(3):496-505
-
-
Free full text
-
Abstract
BACKGROUND Energy expenditure (EE) increases with overfeeding, but it is unclear how rapidly this is related to changes in body composition, increased body weight, or diet. OBJECTIVE The objective was to quantify the effects of excess energy from fat or protein on energy expenditure of men and women living in a metabolic chamber. DESIGN We conducted a randomized controlled trial in 25 participants who ate ∼40% excess energy for 56 d from 5%, 15%, or 25% protein diets. Twenty-four-hour EE (24EE) and sleeping EE (SleepEE) were measured on days 1, 14, and 56 of overfeeding and on day 57 while consuming the baseline diet (usually day 57). Metabolic and molecular markers of muscle metabolism were measured in skeletal muscle biopsy specimens. RESULTS In the low-protein diet group whose excess energy was fat, the 24EE and SleepEE did not increase during the first day of overfeeding. When extra energy contained protein, both 24EE and SleepEE increased in relation to protein intake (r = 0.50, P = 0.02). The 24EE over 8 wk in all 3 groups was correlated with protein intake (r = 0.60, P = 0.004) but not energy intake (r = 0.16; P = 0.70). SleepEE was unchanged by overfeeding in the low-protein diet group, and baseline surface area predicted increased 24EE in this group. Protein and fat oxidation were reciprocally related during overfeeding. Observed 24EE was higher than predicted on days 1 (P ≤ 0.05), 14 (P = 0.0001), and 56 (P = 0.0007). There was no relation between change in fat mass and change in EE. CONCLUSIONS Excess energy, as fat, does not acutely increase 24EE, which rises slowly as body weight increases. Excess energy as protein acutely stimulates 24EE and SleepEE. The strongest relation with change in 24EE was the change in energy expenditure in tissue other than muscle or fat-free mass.
-
7.
Perceptual effects and efficacy of intermittent or continuous blood flow restriction resistance training.
Fitschen, PJ, Kistler, BM, Jeong, JH, Chung, HR, Wu, PT, Walsh, MJ, Wilund, KR
Clinical physiology and functional imaging. 2014;(5):356-63
Abstract
Blood flow restriction (BFR) exercise may be an alternative form of resistance training; however, a side of effect of BFR resistance exercise is acute muscle pain. Typically, BFR exercise studies restrict blood flow with a cuff continuously during the exercise bout, including rest periods. However, others have used intermittent BFR where the cuff is inflated only during sets. We performed two studies to compare intermittent and continuous BFR exercise. In study one, eleven subjects randomly proceeded through three treatments of unilateral leg extensions to failure: (i) continuous BFR, (ii) intermittent BFR and (iii) control (exercise without BFR). Pain measurements were taken immediately after each set. In study two, subjects (n = 32) underwent a 5-week resistance training programme after random assignment to one of the three conditions. Lean mass and strength were assessed at baseline and after training. Continuous BFR resulted in significantly greater pain than intermittent BFR or control. Both BFR conditions resulted in significantly fewer repetitions to failure than control. This suggests that an acute bout of intermittent BFR exercise may produce as much muscle fatigue as an acute bout of continuous BFR exercise, but with less pain. With training, maximal knee extension (P = 0·033) and maximum knee flexion (P = 0·007) strength increased among all groups. There were no significant differences between groups in strength or lean mass. These results suggest that short-term low-load resistance training increases muscle strength to a similar extent as low-load resistance training without BFR.
-
8.
Acute effects of proprioceptive neuromuscular facilitation and static stretching on maximal voluntary contraction and muscle electromyographical activity in indoor soccer players.
Reis, Eda F, Pereira, GB, de Sousa, NM, Tibana, RA, Silva, MF, Araujo, M, Gomes, I, Prestes, J
Clinical physiology and functional imaging. 2013;(6):418-22
Abstract
The aim was to investigate and compare the effects of proprioceptive neuromuscular facilitation (PNF) and static stretching (SS) on maximal voluntary contraction (MVC) and muscle activation in indoor soccer players. Thirty-three young adult men were divided into two groups: (i) sedentary and (ii) trained. Each group completed three different experimental trials: SS, PNF and no stretching (NS). The MVC of knee extension was evaluated before and immediately after each condition along with electromyography from the vastus lateralis (VL) and rectus femoris (RF) muscles of the dominant leg. PNF or SS techniques induced no decrease on MVC and muscle electromyographical activity in indoor soccer players (P>0·05). The electromyography of the RF and VL was lower after SS only in the sedentary group (P≤0·05). Short-duration PNF or SS has no effect on isometric MVC and muscle activity in indoor soccer players.
-
9.
Exercise with low glycogen increases PGC-1α gene expression in human skeletal muscle.
Psilander, N, Frank, P, Flockhart, M, Sahlin, K
European journal of applied physiology. 2013;(4):951-63
Abstract
Recent studies suggest that carbohydrate restriction can improve the training-induced adaptation of muscle oxidative capacity. However, the importance of low muscle glycogen on the molecular signaling of mitochondrial biogenesis remains unclear. Here, we compare the effects of exercise with low (LG) and normal (NG) glycogen on different molecular factors involved in the regulation of mitochondrial biogenesis. Ten highly trained cyclists (VO(2max) 65 ± 1 ml/kg/min, W max 387 ± 8 W) exercised for 60 min at approximately 64 % VO(2max) with either low [166 ± 21 mmol/kg dry weight (dw)] or normal (478 ± 33 mmol/kg dw) muscle glycogen levels achieved by prior exercise/diet intervention. Muscle biopsies were taken before, and 3 h after, exercise. The mRNA of peroxisome proliferator-activated receptor-γ coactivator-1 was enhanced to a greater extent when exercise was performed with low compared with normal glycogen levels (8.1-fold vs. 2.5-fold increase). Cytochrome c oxidase subunit I and pyruvate dehydrogenase kinase isozyme 4 mRNA were increased after LG (1.3- and 114-fold increase, respectively), but not after NG. Phosphorylation of AMP-activated protein kinase, p38 mitogen-activated protein kinases and acetyl-CoA carboxylase was not changed 3 h post-exercise. Mitochondrial reactive oxygen species production and glutathione oxidative status tended to be reduced 3 h post-exercise. We conclude that exercise with low glycogen levels amplifies the expression of the major genetic marker for mitochondrial biogenesis in highly trained cyclists. The results suggest that low glycogen exercise may be beneficial for improving muscle oxidative capacity.
-
10.
Coingestion of whey protein and casein in a mixed meal: demonstration of a more sustained anabolic effect of casein.
Soop, M, Nehra, V, Henderson, GC, Boirie, Y, Ford, GC, Nair, KS
American journal of physiology. Endocrinology and metabolism. 2012;(1):E152-62
Abstract
When consumed separately, whey protein (WP) is more rapidly absorbed into circulation than casein (Cas), which prompted the concept of rapid and slow dietary protein. It is unclear whether these proteins have similar metabolic fates when coingested as in milk. We determined the rate of appearance across the splanchnic bed and the rate of disappearance across the leg of phenylalanine (Phe) from coingested, intrinsically labeled WP and Cas. Either [¹⁵N]Phe or [¹³C-ring C₆]Phe was infused in lactating cows, and the labeled WP and Cas from their milk were collected. To determine the fate of Phe derived from different protein sources, 18 healthy participants were studied after ingestion of one of the following: 1) [¹⁵N]WP, [¹³C]Cas, and lactose; 2) [¹³C]WP, [¹⁵N]Cas, and lactose; 3) lactose alone. At 80-120 min, the rates of appearance (R(a)) across the splanchnic bed of Phe from WP and Cas were similar [0.068 ± 0.010 vs. 0.070 ± 0.009%/min; not significant (ns)]. At time 220-260 min, Phe appearance from WP had slowed (0.039 ± 0.008%/min, P < 0.05) whereas Phe appearance from Cas was sustained (0.068 ± 0.013%/min). Similarly, accretion rates across the leg of Phe absorbed from WP and Cas were not different at 80-120 min (0.011 ± 0.002 vs. 0.012 ± 0.003%/min; ns), but they were significantly lower for WP (0.007 ± 0.002%/min) at 220-260 min than for Cas (0.013 ± 0.002%/min) at 220-260 min. Early after meal ingestion, amino acid absorption and retention across the leg were similar for WP and Cas, but as rates for WP waned, absorption and assimilation into skeletal muscle were better retained for Cas.