Research - XX Muscle

Women can discuss training, diet, nutrition, supplementation and other things here. Research specific to females and children will be posted here.

Research - XX Muscle

Postby Canuck Singh » Mon Jul 21, 2008 12:29 pm

GENDER DIFFERENCES IN CENTRAL AND PERIPHERAL FACTORS OF SKELETAL MUSCLE FATIGUE
Typically, women are less prone to fatigue during weight training than men due in part to the differences in muscle mass. Lower amounts of muscle seen in most women require less oxygen and use oxygen faster at the same workload as men. This equates to higher endurance during strength training.
However, what happens when you compare women and men with the same amount of muscle mass? Does this observation still stand? The study: During a leg extension exercise protocol, women were matched with men with the same amount of lean muscle mass. The results showed that women were no longer more resistant to fatigue, and interestingly, the men weren't any stronger.
So really, there's no gender difference in muscle oxygen demand and use, and therefore, no difference in resistance to fatigue. Women’s muscle is the same quality as men’s and demands the same requirements—at least in the leg extensors.
Also, there are no differences in strength when you compare women and men with the same amount of muscle. (16)

CFOS MRNA EXPRESSION IN SKELETAL MUSCLE AFTER EXERCISE DEPENDS ON THE PHASE OF THE MENSTRUAL CYCLE IN FEMALE ATHLETES
Have you ever heard a woman say she didn’t feel as strong during certain "times of the month" as she did during others? Well, also during this time you may notice she’s not as powerful in the gym as she normally is, and she lacks the energy to perform her normal training program. She might try to blame it on cramps or some other female term that you’d rather not hear about, but interestingly there appears to be a gene-mediated mechanism behind her complaints.
The purpose of this study was to measure the concentration of cFOS gene and certain hormonal receptors in female athletes after one hour of endurance or power exercise during the first and last part of their menstrual cycles. cFOS is a gene believed to be involved in the regulation and expression of a variety of other proteins in the muscle, and therefore would have an impact on muscular strength and power.
In this study, females performed an endurance exercise test (cycling one hour at 70% of their VO2max) and a series of maximal power exercise bouts (one hour total) in the follicular phase (day 4-5) and the luteal phase (day 20-21) of their cycles. Muscle biopsies were taken and the mRNA expression of cFOS and of estrogen (ER), progesterone (PR), and androgen (AR) receptors were determined.
Results: There were no differences in expression of ER, PR, and AR between each exercise test and during different phases of the menstrual cycle. However, cFOS gene expression was increased in response to exercise and it was amplified more in the follicular phase.
Conclusion: These results demonstrate (for the first time) cycle dependent differences in the responsibility of a skeletal muscle gene to exercise. cFOS as a transcription factor may be involved in the regulation of the expression of a variety of other muscle genes responsible for differences in a phase dependent trainability in female athletes.
Finally, scientific proof that there's a decline in a woman’s strength during certain times of the month! Higher levels of cFOS after training during the follicular phase would help skeletal muscle to recover quicker and may aid in growth of muscle protein. This gene would enable a woman to train harder because her muscles would be more anabolic.
It was interesting to see that hormonal receptors like ER and AR weren't altered in response to exercise and they didn’t change throughout the menstrual cycle.
In summary, the best time for a woman to train intensely would be a few days after her period. This is an aspect that trainers and athletes can utilize to structure their training programs. A woman would be encouraged to lift heavier in the follicular phase and go lighter during the luteal phase. (17)


CONTINUOUS VS FRACTIONALIZED EXERCISE ON CALORIC EXPENDITURE IN NON-OBESE AND OBESE FEMALES.
The study by Altena et al showed us that continuous and intermittent (fractionalized) aerobic exercise burned the same total amount of calories in men and women. The following study is specific to women and looks at differences in caloric expenditure in these two types of exercise and whether obesity affects the total amount of calories burned.
The study: Eight obese and non-obese young women performed either 30 minutes of continuous exercise, 3 x 10 minute sessions of intermittent exercise, or no exercise at all (control group). Caloric expenditure of total energy, fat, and carbohydrate were measured after each protocol and after eating a meal (post-prandial caloric expenditure).
Results: There were no differences in total calories burned between the two exercise sessions, and more calories were burned with exercise than after no exercise whatsoever. Non-obese women burned more total calories and more carbohydrate than obese women during exercise but there were no differences in fat oxidation between either of the exercise groups. After a post-workout meal, there was no increase in caloric expenditure compared to sedentary post-prandial caloric expenditure.
Conclusion: Contrary to previous findings in men, women utilize less fat and more carbohydrate during exercise, and prior exercise doesn't affect post-prandial caloric expenditure.
Once again, equal calories are burned during 30 minutes of continuous and fractionalized cardio at the same exercise intensity. So, if you find it difficult to do 30 minutes of cardio (or any cardio at all for that matter), you can do three separate ten minute sessions any way you want and you’ll burn the same amount of calories (assuming you're working at the same intensity overall).
Also, two studies appear to contradict previous findings. First, as suggested by Katsiaras et al, while obese women did oxidize less energy and carbohydrate than non-obese women, they didn't appear to burn less fat, at least during an exercise session, since fat oxidation at rest wasn't measured.
The second contradiction is with the work of Venables et al. The current study in question noted that women burned less fat and more carbs than men during training, and exercise didn't enhance metabolism after a meal. Venables et al., on the other hand, demonstrated the opposite: females had higher fat oxidation rates compared to males.
These opposing results may be explained by differences in exercise intensity, and the fact that subjects exercised to exhaustion in the study by Venables et al. Also, the small sample size in this study could've influenced the results. To date, there's no clear consensus on whether there's a gender difference in substrate utilization during exercise; some studies find that women burn more fat and less carbs, whereas others find the opposite. Maybe you men should reconsider that **** change after all!
The bottom line is that if you want to lose any body fat at all, regardless of your gender, you need to be consistent with your workouts and stop bingeing on donuts and pop! (18)
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Re: Research - XX Muscle

Postby bugatti » Mon Apr 21, 2014 10:46 pm

women don't have muscle more than man
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