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A Comparison of Strength and Muscle Mass Increases During Resistance Training in Young Women

Chilibeck PD et. al. A comparison of strength and muscle mass increases during resistance training in young women. Eur J Appl Physiol Occup Physiol. 1998;77(1-2):170-5.

Strength gains with resistance training are due to muscle hypertrophy and nervous system adaptations. The contribution of either factor may be related to the complexity of the exercise task used during training. The purpose of this investigation was to measure the degree to which muscle hypertrophy contributes to gains in strength during exercises of varying complexity. Nineteen young women resistance trained twice a week for 20 weeks, performing exercises designed to provide whole-body training. The lean mass of the trunk, legs and arms was measured by dual energy x-ray absorptiometry and compared to strength gains (measured as the 1-repetition maximum) in bench press, leg press and arm curl exercises, pre-, mid- (10 weeks) and post-training. No changes were found in a control group of ten women. For the exercise group, increases in bench press, leg press and arm curl strength were significant from pre- to mid-, and from mid- to post-training (P < 0.05). In contrast, increases in the lean mass of the body segments used in these exercises followed a different pattern. Increases in … Read More

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Dietary Restraint and Cortisol Levels – Research Review

I don’t think I’ve done a research review in a while and even though I imagine some visitors to the site may be getting tired of topics related to the book I’m working on, well, that’s what I’m currently working on so it’s kind of at the top of my mind right now.

Today, I want to do a research review but for various reasons, mainly the abstract being too long to paste, I want to do it a little bit differently. The paper I want to look at is titled

McLean JA et. al. Cognitive dietary restraint is associated with higher urinary cortisol excretion in healthy premenopausal women. Am J Clin Nutr. 2001 Jan;73(1):7-12. And you can get the free full text here.

Background

I imagine most visitors to my site are familiar with the hormone cortisol, even if many aren’t quite clear on what it does. Cortisol is often thought of as a “bad” hormone but this is too simplistic; what cortisol does in the body depends on a host of factors. The primary of these is whether it is released in a pulsatile and acute fashion (basically small pulses) or is elevated chronically. The first situation … Read More

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Impact of the Menstrual Cycle on Determinants of Energy Intake – Research Review

L Davidsen et. al. Impact of the menstrual cycle on determinants of energy balance: a putative role in weight loss attempts. International Journal of Obesity (2007) 31, 887-890

Abstract: Women’s weight and body composition is significantly influenced by the female sex-steroid hormones. Levels of these hormones fluctuate in a defined manner throughout the menstrual cycle and interact to modulate energy homeostasis. This paper reviews the scientific literature on the relationship between hormonal changes across the menstrual cycle and components of energy balance, with the aim of clarifying whether this influences weight loss in women. In the luteal phase of the menstrual cycle it appears that women’s energy intake and energy expenditure are increased and they experience more frequent cravings for foods, particularly those high in carbohydrate and fat, than during the follicular phase. This suggests that the potential of the underlying physiology related to each phase of the menstrual cycle may be worth considering as an element in strategies to optimize weight loss. Studies are needed to assess the weight loss outcome of tailoring dietary recommendations and the degree of energy restriction to each menstrual phase throughout a weight management program, taking these preliminary findings into account.

 

Background

Amusingly, … Read More

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Reduced Fat and Reduced Carbohydrate Diets and Fat Loss – Research Review

Hall, KD et. al. Calorie for Calorie, Dietary Fat Restriction Results in More Body Fat Loss than Carbohydrate Restriction in People with Obesity Cell Metabolism  Cell Metabolism (2015) 22: 1–10.

Abstract

Dietary carbohydrate restriction has been purported to cause endocrine adaptations that promote body fat loss more than dietary fat restriction. We selectively restricted dietary carbohydrate versus fat for 6 days following a 5-day baseline diet in 19 adults with obesity confined to a metabolic ward where they exercised daily. Subjects received both isocaloric diets in random order during each of two inpatient stays. Body fat loss was calculated as the difference between daily fat intake and net fat oxidation measured while residing in a metabolic chamber. Whereas carbohydrate restriction led to sustained increases in fat oxidation and loss of 53 ± 6 g/day of body fat, fat oxidation was un- changed by fat restriction, leading to 89 ± 6 g/day of fat loss, and was significantly greater than carbohydrate restriction (p = 0.002). Mathematical model simulations agreed with these data, but predicted that the body acts to minimize body fat differences with prolonged isocaloric diets varying in carbohydrate and fat.

Background on Reduced Fat and Reduced Carbohydrate Diets

For … Read More

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Effects of Low Versus High Load Resistance Training – Research Review

Schoenfeld BJ et. al. Effects of Low Versus High Load Resistance Training on Muscle Strength and Hypertrophy in Well-Trained Men.J Strength Cond Res. 2015 Apr 3. [Epub ahead of print]

Abstract

The purpose of this study was to compare the effect of low- versus high-load resistance training (RT) on muscular adaptations in well-trained subjects. Eighteen young men experienced in RT were matched according to baseline strength, and then randomly assigned to 1 of 2 experimental groups: a low-load RT routine (LL) where 25-35 repetitions were performed per set per exercise (n = 9), or a high-load RT routine (HL) where 8-12 repetitions were performed per set per exercise (n = 9). During each session, subjects in both groups performed 3 sets of 7 different exercises representing all major muscles. Training was carried out 3 times per week on non-consecutive days, for 8 total weeks. Both HL and LL conditions produced significant increases in thickness of the elbow flexors (5.3 vs. 8.6%, respectively), elbow extensors (6.0 vs. 5.2%, respectively), and quadriceps femoris (9.3 vs. 9.5%, respectively), with no significant differences noted between groups. Improvements in back squat strength were significantly greater for HL compared to LL (19.6 vs. 8.8%, respectively) and

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