Volume # 37

Geeky Friday

 

Hey folks!

 

First of all, hope you’ve all had an awesome and productive weekend. I’ve been working my butt off in the ER, and definitively feel ready for the weekend.  I spent last weekend in London with some very dear friends of mine, which is why we skipped the GF last week (no, I did not sit in a pub in London with my iPad, reading studies…).

 

Anyhow, here are the latest studies for you. Click the title of the ones you are interested in to go to pubmed, many of them are accessible in full text for free.

 

As many of you know, I’m on a fat loss diet right now, getting ready for a photo shoot. Just wanted to give you an quick update on that one as well, as many of you have been asking about it.  I’m doing pretty good. Hunger is still not a big problem and I have not lost any strength yet (on the contrary, I keep increasing the weights on most lifts). I’d say I’m about 4 kilos from my absolutely best shape.

 
Rygg jpeg
Yeah, In desperate need for a haircut
 

Anyway, I’m going back to my potatos but I want to wish you all a very awesome week end!

 

Talk soon!

 

 
Bojan

 

 

Make sure you keep supporting my work by sharing this article with your friends and followers. We need to spread the science and integrate it with the massive amounts of personal experience that is already out there- so we can make the best and most effective programs for ourselves and our clients. The share buttons are on you left. Also, hit me up on Facebook & Twitter . Interacting with like-minded on day to day basis is one of the main reasons I run this site. Lastly, feel free to leave any questions or feedback in the comments below; I look much forward to hearing from you.

 

Effects of intermittent fasting on metabolism in men.

Rev Assoc Med Bras. 2013 Mar-Apr;59(2):167-73

Authors: Azevedo FR, Ikeoka D, Caramelli B

Abstract: This review analyzes the available literature on the impact of intermittent fasting (IF), a nutritional intervention, on different aspects of metabolism. The epidemic of metabolic disturbances, such as obesity, metabolic syndrome (MS), and diabetes mellitus type 2 has led to an increase in the prevalence of cardiovascular diseases, and affected patients might significantly benefit from modifications in nutritional habits. Recent experimental studies have elucidated some of the metabolic mechanisms involved with IF. Animal models have shown positive changes in glucose (lower plasma glucose and insulin levels) and in lipid metabolism (reduced visceral fat tissue and increased plasma adiponectin level), and an increased resistance to stress. Despite the limited number of samples studied, positive results have been reported on the impact of IF for human health. IF is reported to improve the lipid profile; to decrease inflammatory responses, reflected by changes in serum adipokine levels; and to change the expression of genes related to inflammatory response and other factors. Studies on obese individuals have shown that patient compliance was greater for IF than other traditional nutritional approaches (calorie restriction), and IF was found to be associated with low oxidative stress. Recent reports suggest that IF exerts a positive impact on the metabolic derangements commonly associated with cardiovascular diseases, and that it may be a viable and accessible intervention for most individuals. Therefore, further clinical studies are essential to test the effectiveness of IF in preventing and controlling metabolic and cardiovascular diseases.

 

Effects of Testosterone and Progressive Resistance Exercise in Healthy, Highly Functioning Older Men With Low-Normal Testosterone Levels.

J Clin Endocrinol Metab. 2013 Mar 26;

Authors: Hildreth KL, Barry DW, Moreau KL, Vande Griend J, Meacham RB, Nakamura T, Wolfe P, Kohrt WM, Ruscin JM, Kittelson J, Cress ME, Ballard R, Schwartz RS

Abstract: Context:Aging in men is associated with reduced testosterone (T) levels and physiological changes leading to frailty, but the benefits of T supplementation are inconclusive.Objective:We studied the effects of T supplementation with and without progressive resistance training (PRT) on functional performance, strength, and body composition.Design, Setting, and Participants:We recruited 167 generally healthy community-dwelling older men (66 ± 5 years) with low-normal baseline total T levels (200-350 ng/dL).Intervention:Subjects were randomized to placebo or transdermal T gel [2 doses targeting either a lower (400-550 ng/dL) or higher (600-1000 ng/dL) T range] and to either PRT or no exercise for 12 months.Main Outcome Measure:The primary outcome was functional performance, whereas secondary outcomes were strength and body composition.Results:A total of 143 men completed the study. At 12 months, total T was 528 ± 287 ng/dL in subjects receiving any T and 287 ± 65 ng/dL in the placebo group. In the PRT group, function and strength were not different between T- and placebo-treated subjects, despite greater improvements in fat mass (P = .04) and fat-free mass (P = .01) with T. In the non-PRT group, T did not improve function but improved fat mass (P = .005), fat-free mass (P = .03), and upper body strength (P = .03) compared with placebo. There were fewer cardiovascular events in the T-treated groups compared with placebo.Conclusions:T supplementation was well tolerated and improved body composition but had no effect on functional performance. T supplementation improved upper body strength only in nonexercisers compared with placebo.

 

Skeletal muscle hypertrophy and regeneration: interplay between the myogenic regulatory factors (MRFs) and insulin-like growth factors (IGFs) pathways.

Cell Mol Life Sci. 2013 Apr 4;

Authors: Zanou N, Gailly P

Abstract: Adult skeletal muscle can regenerate in response to muscle damage. This ability is conferred by the presence of myogenic stem cells called satellite cells. In response to stimuli such as injury or exercise, these cells become activated and express myogenic regulatory factors (MRFs), i.e., transcription factors of the myogenic lineage including Myf5, MyoD, myogenin, and Mrf4 to proliferate and differentiate into myofibers. The MRF family of proteins controls the transcription of important muscle-specific proteins such as myosin heavy chain and muscle creatine kinase. Different growth factors are secreted during muscle repair among which insulin-like growth factors (IGFs) are the only ones that promote both muscle cell proliferation and differentiation and that play a key role in muscle regeneration and hypertrophy. Different isoforms of IGFs are expressed during muscle repair: IGF-IEa, IGF-IEb, or IGF-IEc (also known as mechano growth factor, MGF) and IGF-II. MGF is expressed first and is observed in satellite cells and in proliferating myoblasts whereas IGF-Ia and IGF-II expression occurs at the state of muscle fiber formation. Interestingly, several studies report the induction of MRFs in response to IGFs stimulation. Inversely, IGFs expression may also be regulated by MRFs. Various mechanisms are proposed to support these interactions. In this review, we describe the general process of muscle hypertrophy and regeneration and decipher the interactions between the two groups of factors involved in the process.

 

Skeletal muscle oxygen uptake in obese patients: functional evaluation by knee-extension exercise.

Eur J Appl Physiol. 2013 Apr 19;

Authors: Lazzer S, Salvadego D, Porcelli S, Rejc E, Agosti F, Sartorio A, Grassi B

Abstract: We hypothesized, in a group of obese women (OB), a more significant impairment of aerobic metabolism during knee extension (KE) exercise vs. that described during cycle ergometer exercise, lending support to the role of skeletal muscles in limiting exercise tolerance in OB. Eleven OB (age 29.5 ± 5.5 years, body mass index 43.2 ± 5.4 kg m(-2)) and 10 non-obese controls (CTRL) women were tested. Fat-free mass of a lower-limb (FFMLL) was assessed by a densitometer. Heart rate (HR) and pulmonary O2 uptake ([Formula: see text]O2) were determined during incremental exercise tests to voluntary exhaustion carried out on a custom-built KE ergometer and on a cycle ergometer (CE). FFMLL and maximal isometric force of KE muscles were higher in OB vs. CTRL (+42.4 and +46.2 %, respectively). Peak work rate was significantly lower in OB (-18.4 %) vs. CTRL in CE, but not in KE. Expressed in mL min(-1), peak [Formula: see text]O2 was not different in OB vs. CTRL in CE and in KE. After it was divided per unit of FFM involved in the exercises, peak [Formula: see text]O2 was significantly lower in OB vs. CTRL, both for CE (-19 %) and KE (-33 %). Expressed per unit of exercising muscle mass, peak oxidative function is impaired in OB. The impairment is more pronounced after limitations related to cardiovascular O2 delivery are reduced. In OB muscle hypertrophy and the increased muscle force allow to preserve exercise tolerance during aerobic exercises carried out by relatively small muscle masses.

 

Effect of adding single-joint exercises to a multi-joint exercise resistance-training program on strength and hypertrophy in untrained subjects.

Appl Physiol Nutr Metab. 2013 Mar;38(3):341-4

Authors: Gentil P, Soares SR, Pereira MC, Cunha RR, Martorelli SS, Martorelli AS, Bottaro M

Abstract: The aim of this study was to examine the effect of adding single-joint (SJ) exercises to a multi-joint (MJ) exercise resistance-training program on upper body muscle size and strength. Twenty-nine untrained young men participated in a 10-week training session. They were randomly divided in 2 groups: the MJ group performed only MJ exercises (lat pulldown and bench press); the MJ+SJ group performed the same MJ exercises plus SJ exercises (lat pulldown, bench press, elbow flexion, and elbow extension). Before and after the training period, the muscle thickness (MT) of the elbow flexors was measured with ultrasound, and peak torque (PT) was measured with an isokinetic dynamometer. There was a significant (p < 0.05) increase in MT (6.5% for MJ and 7.04% for MJ+SJ) and PT (10.40% for MJ and 12.85% for MJ+SJ) in both groups, but there were no between-group differences. Therefore, this study showed that the inclusion of SJ exercises in a MJ exercise training program resulted in no additional benefits in terms of muscle size or strength gains in untrained young men.

 

Effects of Different Uphill Interval-Training Programs on Running Economy and Performance.

Int J Sports Physiol Perform. 2013 Mar 26;

Authors: Barnes KR, Hopkins WG, McGuigan MR, Kilding AE

Abstract: PURPOSE: Runners use uphill running as a movement-specific form of resistance training to enhance performance. However, the optimum parameters for prescribing intervals are unknown. We adopted a dose-response design to investigate the effects of various uphill interval-training programs on physiological and performance measures. METHODS: Twenty well-trained runners performed an incremental treadmill test to determine aerobic and biomechanical measures, a series of jumps on a force plate to determine neuromuscular measures, and a 5-km time-trial. Runners were then randomly assigned to one of five uphill interval-training programs. After 6 wk all tests were repeated. To identify the optimum training program for each measure, each runner’s percent change was modeled as a quadratic function of the rank order of the intensity of training. Uncertainty in the optimum training and in the corresponding effect on the given measure was estimated as 90% confidence limits using bootstrapping. RESULTS: There was no clear optimum for time-trial performance, and the mean improvement over all intensities was 2.0% (confidence limits ±0.6%). The highest intensity was clearly optimal for running economy (improvement of 2.4%, ±1.4%) and for all neuromuscular measures, whereas other aerobic measures were optimal near the middle intensity. There were no consistent optima for biomechanical measures. CONCLUSIONS: These findings support anecdotal reports for incorporating uphill interval training in the training programs of distance runners to improve physiological parameters relevant to running performance. Until more data are obtained, runners can assume that any form of high-intensity uphill interval training will benefit 5-km time-trial performance.

 

Effects of Prostaglandins and COX Inhibiting Drugs on Skeletal Muscle Adaptations to Exercise.

J Appl Physiol. 2013 Mar 28;

Authors: Trappe TA, Liu SZ

Abstract: It has been ~40 years since the discovery that prostaglandins are produced by exercising skeletal muscle, and since the discovery that inhibition of prostaglandin synthesis is the mechanism of action of what are now known as cyclooxygenase (COX)-inhibiting drugs. Since that time, it has been established that prostaglandins are made during and after aerobic and resistance exercise and have a potent paracrine/autocrine effect on muscle metabolism. Consequently, it has also been determined that orally consumed doses of COX-inhibitors can profoundly influence muscle prostaglandin synthesis, muscle protein metabolism, and numerous other cellular processes that regulate muscle adaptations to exercise loading. Although data from acute human exercise studies, as well as animal and cell culture data would predict regular consumption of a COX-inhibitor during exercise training would dampen the typical muscle adaptations, the chronic data do not support this conjecture. From the studies in young and older individuals lasting from 1.5-4 months, no interfering effects of COX-inhibitors on muscle adaptations to resistance exercise training have been noted. In fact, in older individuals a substantial enhancement of muscle mass and strength has been observed. The collective findings of the prostaglandin/COX pathway regulation of skeletal muscle responses and adaptations to exercise are compelling. Considering the discoveries in other areas of COX regulation of health and disease there is certainly an interesting future of investigation in this re-emerging area, especially as it pertains to older individuals and the condition of sarcopenia, as well as exercise training and performance of individuals of all ages.

 

Sex-based comparisons of myofibrillar protein synthesis after resistance exercise in the fed state.

J Appl Physiol. 2012 Jun;112(11):1805-13

Authors: West DW, Burd NA, Churchward-Venne TA, Camera DM, Mitchell CJ, Baker SK, Hawley JA, Coffey VG, Phillips SM

Abstract: We made sex-based comparisons of rates of myofibrillar protein synthesis (MPS) and anabolic signaling after a single bout of high-intensity resistance exercise. Eight men (20 ± 10 yr, BMI = 24.3 ± 2.4) and eight women (22 ± 1.8 yr, BMI = 23.0 ± 1.9) underwent primed constant infusions of l-[ring-(13)C(6)]phenylalanine on consecutive days with serial muscle biopsies. Biopsies were taken from the vastus lateralis at rest and 1, 3, 5, 24, 26, and 28 h after exercise. Twenty-five grams of whey protein was ingested immediately and 26 h after exercise. We also measured exercise-induced serum testosterone because it is purported to contribute to increases in myofibrillar protein synthesis (MPS) postexercise and its absence has been hypothesized to attenuate adaptative responses to resistance exercise in women. The exercise-induced area under the testosterone curve was 45-fold greater in men than women in the early (1 h) recovery period following exercise (P < 0.001). MPS was elevated similarly in men and women (2.3- and 2.7-fold, respectively) 1-5 h postexercise and after protein ingestion following 24 h recovery. Phosphorylation of mTOR(Ser2448) was elevated to a greater extent in men than women acutely after exercise (P = 0.003), whereas increased phosphorylation of p70S6K1(Thr389) was not different between sexes. Androgen receptor content was greater in men (main effect for sex, P = 0.049). Atrogin-1 mRNA abundance was decreased after 5 h recovery in both men and women (P < 0.001), and MuRF-1 expression was elevated in men after protein ingestion following 24 h recovery (P = 0.003). These results demonstrate minor sex-based differences in signaling responses and no difference in the MPS response to resistance exercise in the fed state. Interestingly, our data demonstrate that exercise-induced increases in MPS are dissociated from postexercise testosteronemia and that stimulation of MPS occurs effectively with low systemic testosterone concentrations in women.

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