Volume #4

Dear friends,

I’m so glad you are back and ready for another Geeky Friday – summary of the latest fitness and nutrition research. A few quick notes before I let you get your geek on. Unfortunately, I don’t have enough time right now to write reviews of the research myself, but I am however glad to point you to some resources you can use if you are ready to take your knowledge to the next level.

My man Bret Contreras just released his Strength and Conditioning Research, a monthly publication summarizing the latest and greatest research in strength and conditioning, bio-mechanics, physical therapy, and physiology. I’ll be signing up for sure and so should you!

If you want to learn more about how you can review fitness research, how to understand the difference between good and bad science, how you can know which knowledge to adapt in your own programming, and where you can find the studies in the first place, I highly recommend Mark Young’s  How To Read Fitness Research.I bought the product myself as soon as it came out and strongly recommend it to anyone interested in understanding how to distinguish between true knowledge and every day bro-scientific fitness bullshit. It’s one of the best investments you’ll make.

Now let’s get to the good stuff:Here are the most interesting abstracts of studies I’ve read this week. Enjoy!

Acute l-arginine supplementation increases muscle blood volume but not strength performance.

Appl Physiol Nutr Metab. 2012 Jan 17;

Authors: Alvares TS, Conte CA, Paschoalin VM, Silva JT, Meirelles CD, Bhambhani YN, Gomes PS

Abstract: l-Arginine (L-arg) is an amino acid precursor to nitric oxide (NO). Dietary supplements containing L-arg have been marketed with the purpose of increasing vasodilation, thereby elevating blood flow to the exercising muscle and enhancing the metabolic response to exercise. Our goal was to identify the acute effect of L-arg supplementation on biceps strength performance, indicators of NO production (nitrite and nitrate – NOx), and muscle blood volume (Mbv) and oxygenation (Mox) during recovery from 3 sets of resistance exercise. Fifteen males participated in a randomized, double-blind, placebo-controlled study. After withdrawing resting blood samples, the subjects were supplemented with 6 g of L-arg (ARG) or placebo (PLA). Monitoring of Mbv and Mox with near-infrared spectroscopy began 30 min after supplementation and lasted for 60 min. The exercise protocol (3 sets of 10 maximal voluntary contractions of isokinetic concentric elbow extension at 60°·s(-1), 2-min rest between sets) was initiated 80 min after supplementation. Blood samples were drawn at 30, 60, 90, and 120 min after supplementation. Repeated measures ANOVA showed that Mbv significantly (p ≤ 0.05) increased in ARG compared with the PLA during the recovery period of each set of resistance exercise. NOx, Mox, peak torque, total work, and set total work were not significantly different between groups. We found that acute L-arg supplementation increases Mbv during recovery from sets of resistance exercise with no increase in strength performance. It is still premature to recommend nutritional supplements containing L-arg as an ergogenic aid to increase muscle strength during resistance training in healthy subjects.

Metabolic and structural adaptations to exercise in chronic intermittent fasted rats.

Am J Physiol. 1988 Jun;254(6 Pt 2):R877-84.

Authors: Favier RJ, Koubi HE.

Abstract: The effect of repetitive alternance of 3 days fasting and 3 days refeeding on morphological and biochemical ability to perform exercise was investigated in adult male rats. At the end of 10 wk of chronic intermittent fasting, the rats had consumed 20% less food but were able to maintain their initial body weight. Intermittent fasted rats (IF) had significantly lower carcass fat but had maintained the percent contribution of proteins to total carcass weight. The relative mass of liver, heart, kidney, and muscles was not affected by such dietary manipulation. Both glycolytic and oxidative enzyme capacities were reduced in IF rat muscles. In response to exercise (2 h of swimming), control rats displayed hypoglycemia, whereas IF ratswere able to maintain plasma glucose level in spite of a reduced energy supply from liver (low glycogen stores) and adipose tissue (low plasma free fatty acid levels). This had been obtained by accumulating glycogen and triglycerides in muscles and by deriving energy for muscular contraction from the in situ breakdown of these energetic substrates. In addition, although IF rats displayed a markedly reduced liver protein content, the liver exercise-induced protein breakdown was abolished in these animals.

cAMP signaling in skeletal muscle adaptation: hypertrophy, metabolism and regeneration.

Am J Physiol Endocrinol Metab. 2012 Feb 21;

Authors: Berdeaux R, Stewart R

Abstract: Among organ systems, skeletal muscle is perhaps the most structurally specialized. The remarkable subcellular architecture of this tissue allows it to empower movement with instruction from motor neurons. Despite this high degree of specialization, skeletal muscle also has intrinsic signaling mechanisms that allow adaptation to long-term changes in demand and regeneration after acute damage. The second messenger 3′-5′-cyclic adenosine monophosphate (cAMP) not only elicits acute changes within myofibers during exercise but also contributes to myofiber size and metabolic phenotype in the long term. Strikingly, sustained activation of cAMP signaling leads to pronounced hypertrophic responses in skeletal myofibers through largely elusive molecular mechanisms. These pathways can promote hypertrophy and combat atrophy in animal models of disorders including muscular dystrophy, age-related atrophy, denervation injury, disuse atrophy, cancer cachexia and sepsis. cAMP also participates in muscle development and regeneration mediated by muscle precursor cells, and thus downstream signaling pathways may potentially be harnessed to promote muscle regeneration in patients with acute damage or muscular dystrophy. In this review we will summarize studies implicating cAMP signaling in skeletal muscle adaptation. We will also highlight ligands that induce cAMP signaling and downstream effectors that are promising pharmacologic targets

Weight loss and exercise training effect on oxygen uptake and heart rate response to locomotion.

J Strength Cond Res. 2012 Feb 15;

Authors: Hunter GR, Fisher G, Bryan DR, Zuckerman PA

Abstract: Effects of resistance and aerobic training on ease of physical activity during and following weight loss are unknown. Purpose of study is to determine what affect weight loss combined with either aerobic or resistance training has on ease of locomotion (netVO2 and heart rate). It is hypothesized that exercise training will result in increased ease, lower heart rate during locomotion. Seventy three overweight, premenopausal women were assigned to diet and aerobic training, diet and resistance training, or diet only. Subjects were evaluated while overweight, after diet induced weight loss (average 12.5 kg loss), and one year following weight loss (5.5 kg regain). Submaximal walking, grade walking, stair climbing, and bike oxygen uptake and heart rate were measured at all time points. Weight loss diet was 800 kcal/day. Exercisers trained 3 times/wk during weight loss and 2 times/wk during one year follow-up. Resistance training increased strength and aerobic training increased maximum oxygen uptake. Net submaximal oxygen uptake was not affected by weight loss or exercise training. However, heart rate during walking, stair climbing, and bicycling was reduced following weight loss. No significant differences in reduction in heart rate were observed between the 3 treatment groups for locomotion following weight loss. However, during one-year follow-up, exercise training resulted in maintenance of lower submaximal heart rate, while non exercisers increased heart rate during locomotion. Results, suggest that moderately intense exercise is helpful in improving ease of movement following weight loss. Exercise training may be helpful in increasing participation in free living physical activity

Long-term effect of nutritional counselling on desired gain in body mass and lean body mass in elite athletes.

Appl Physiol Nutr Metab. 2011 Aug;36(4):547-54

Authors: Garthe I, Raastad T, Sundgot-Borgen J

Abstract: Lean body mass (LBM) is important in power-related sports. In athletes with heavy training loads and competitions, it may be difficult to increase and maintain LBM during the season. The purpose of this study was to evaluate the long-term effects on body composition after an 8-12 week weight-gain period with or without nutritional guidance. Twenty-one elite athletes where randomized to 1 of 2 groups: the nutritional counselling group (NCG; n = 12, 18.5 ± 1.7 y, 67.8 ± 7.4 kg) and the ad libitum group (ALG; n = 9, 19.6 ± 2.7 y, 74.2 ± 5.7 kg). The NCG followed a meal plan that provided a surplus of 506 ± 84 kcal·day(-1), whereas the ALG had an ad libitum energy intake (EI) during the strength-training (4 sessions per week) intervention. Body mass (BM) and body composition were measured pre- and postintervention, and 6 and 12 months after the intervention. EI in the NCG was normalized after 12 months, whereas EI in the ALG was unchanged during or after the intervention. BM increased more in the NCG than in the ALG during the intervention (4.3% ± 0.9% vs. 1.0% ± 0.6%) and after 12 months (6.0% ± 0.9% vs. 1.8% ± 0.7%). LBM increased in the NCG during the intervention (2.8% ± 0.5%) and after 12 months (4.4% ± 1.0%), whereas LBM in the ALG was unchanged. The NCG managed to maintain and increase BM and LBM after the intervention period. Hence, the focus on nutritional guidance, in addition to strength training, seems to be preferable for obtaining the long-term effect of weight gain in athletes.

Subjective Perception of Sports Performance, Training, Sleep and Dietary Patterns of Malaysian Junior Muslim Athletes during Ramadan Intermittent Fasting.

Asian J Sports Med. 2011 Sep;2(3):167-76

Authors: Singh R, Hwa OC, Roy J, Jin CW, Ismail SM, Lan MF, Hiong LL, Aziz AR

Abstract: PURPOSE: To examine the subjective perception of daily acute fasting on sports performance, training, sleep and dietary patterns of Muslim athletes during the Raadan month.
METHODS: Seven hundred and thirty-four (411 male and 323 female) Malaysian Junior-level Muslim athletes (mean age 16.3 ± 2.6 y) participated in the survey which was designed to establish the personal perception of their sport performance, sleep pattern, food and fluid intake during Ramadan fasting. The survey was conducted during and immediately after the month of Ramadan in 2009.
RESULTS: Twenty-four percent of the athletes perceived that there was an adverse effect of the Ramadan fast on their sporting performance and 29.3% reported that quality of training during Ramadan was also negatively influenced. Majority (48.2%) of the athletes stated that Ramadan fasting did not affect their normal sleep pattern but 66.6% of them complained of sleepiness during the daytime. Half of the athletes (41.4%) maintained the caloric intake during Ramadan as they normally would with the majority of them (76.2%) reporting that they consumed more fluids during Ramadan.
CONCLUSIONS: Overall, Malaysian Junior-level Muslim athletes showed diverse views in their perception of changes in their training, sleep and dietary patterns during Ramadan fast. These individual differences probably indicate differences in the athletes’ adaptability and coping strategies during fasting and training in Ramadan.

Effects of resistance training on arterial stiffness: a meta-analysis.

Br J Sports Med. 2012 Jan 20;

Authors: Miyachi M

Abstract: Background: Regular aerobic exercise prevents and reverses arterial stiffening, but the association between resistance training and arterial stiffness is unclear.AimThis study was performed to conduct a systematic review and meta-analysis of randomised controlled clinical trials (RCTs) assessing the associations between resistance training and changes in arterial stiffness.Methods: MEDLINE and SPORT Discus databases were searched from January 1980 through to April 2011. RCTs evaluating the ability of resistance training to increase arterial stiffness in comparison with a control group were included in the meta-analysis. Two independent reviewers extracted data and assessed the quality of the included studies. Data from 185 reports of eight RCTs (193 participants) were included. Pooled mean differences in arterial stiffness indices (carotid arterial β stiffness and pulse wave velocity (PWV)) between intervention and control groups were calculated using a random-effects model.ResultsThe overall association of resistance training versus control with relative changes in carotid β index or PWV (eight studies; 193 participants) was 10.7% (95% CI 3.4% to 18.0%; I(2), 89%; heterogeneity, p

Effects of Performing Resistance Exercise Before Versus After Aerobic Exercise on Glycemia in Type 1 Diabetes.

Diabetes Care. 2012 Feb 28;

Authors: Yardley JE, Kenny GP, Perkins BA, Riddell MC, Malcolm J, Boulay P, Khandwala F, Sigal RJ

Abstract: OBJECTIVE: To determine the effects of exercise order on acute glycemic responses in individuals with type 1 diabetes performing both aerobic and resistance exercise in the same session. RESEARCH DESIGN AND METHODS: Twelve physically active individuals with type 1 diabetes (HbA(1c) 7.1 ± 1.0%) performed aerobic exercise (45 min of running at 60% Vo(2peak)) before 45 min of resistance training (three sets of eight, seven different exercises) (AR) or performed the resistance exercise before aerobic exercise (RA). Plasma glucose was measured during exercise and for 60 min after exercise. Interstitial glucose was measured by continuous glucose monitoring 24 h before, during, and 24 h after exercise.RESULTS: Significant declines in blood glucose levels were seen in AR but not in RA throughout the first exercise modality, resulting in higher glucose levels in RA (AR = 5.5 ± 0.7, RA = 9.2 ± 1.2 mmol/L, P = 0.006 after 45 min of exercise). Glucose subsequently decreased in RA and increased in AR over the course of the second 45-min exercise bout, resulting in levels that were not significantly different by the end of exercise (AR = 7.5 ± 0.8, RA = 6.9 ± 1.0 mmol/L, P = 0.436). Although there were no differences in frequency of postexercise hypoglycemia, the duration (105 vs. 48 min) and severity (area under the curve 112 vs. 59 units ⋅ min) of hypoglycemia were nonsignificantly greater after AR compared with RA. CONCLUSIONS: Performing resistance exercise before aerobic exercise improves glycemic stability throughout exercise and reduces the duration and severity of postexercise hypoglycemia for individuals with type 1 diabetes.

There you go, I’ve done my part. Now it’s time for you to do yours! Make sure you share 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. Also, hit me up on Facebook, Twitter and Google+. 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.

In strength,

Dr. Bojan

PS. Want more? You can find the old Geeky Friday posts under the RESEARCH category!

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