The Benefits of Strength Training for Women

Geschatte leestijd: 19 minuten The biggest misconception women have about strength training is the fear of looking like female top bodybuilders. The title of this article is therefore not a typo. Strength training offers only benefits for women. Also, or even especially, when aiming to lose fat, strength training plays an important role. In this article, I will discuss these benefits and how strength training contributes to fat loss, but first, I will explain why women naturally do not have the predisposition to build large muscle mass.

“But…I don’t want to get TOO muscular”

Not only women make the remark “I don’t need to get super muscular” unjustly. Many men also make this remark with the exaggeratedly large professional bodybuilders they see on the covers of magazines and online in mind. The thought that this result can be achieved by anyone is a big illusion.

Building large muscle mass is not a button you accidentally press.

The men who have built such enormous physiques are constantly working on it. They sometimes train 6 times a week, twice a day. More importantly, all day long they ensure they have the right nutrients, in the right proportions, at the right time. Additionally, they use supplements specifically aimed at muscle mass, but they mainly grow to superhuman size by combining all this with the use of prohibited substances. Last but not least: you must have the predisposition to build a lot of muscle mass. For men, this includes having the right body type with the right proportion of different types of muscle fibers. Even with the right predisposition, however, it remains a matter of enormous discipline and dedication for men to achieve such large muscle mass. In practice, this turns out to be unattainable for the vast majority of men. Walk into an average gym and you will see at most one or two really muscular guys or men and at least ten times as many men who would like to achieve that but cannot. The human body does not find exaggerated muscle mass functional at all and will try to break it down as soon as insufficient nutrition is provided or insufficient training is done. For women, however, it is natural that they have even less predisposition to muscle mass, mainly due to hormones. I will first explain the reason why women naturally have little to no predisposition to large muscle mass and then discuss the benefits of strength training for women. Finally, I will briefly discuss bodybuilding for women, for those who do wish to build large muscle mass. Finally: what I also want to emphasize is that women should step out of the “comfort cardio zone” and start training with weights. Many women still have a misconception and quickly say:

‘No, I don’t want to become big and muscular.’

A bit of a shame, I think. All that running won’t give you nice round squat buttocks; with strength training and nutrition, you can create the shape you desire. Silvana Joghi is one of the fitness models who signed up via my own blog and with whom I did a photoshoot last year. Speaking of predisposition: A six-pack like hers is hardly achievable for many women without years of dedication to the sport, good nutrition, and the right genes.

Difference in muscle mass between man and woman

So, men already have difficulty building large muscle mass. For women, a lot is needed to achieve a level of muscle mass that could be called “masculine.” The socio-anthropological debate nature versus nurture revolves around the question of whether certain human behaviors or characteristics are caused by natural/biological factors (nature) or by upbringing and environment (nurture). Are men stronger because they play with GI Joe instead of Barbie, or play football instead of doing ballet, or is this biologically determined?

Difference in hormones between men and women

The answer is both. Firstly, hormones play a significant role in the size of muscle mass. Hormones can be seen as messengers that tell the body what to do with certain substances. Should energy, for example, be stored as fat or used to build muscles? Both men and women have both female and male hormones. The difference lies in the ratio. Simply put, men have more male hormones such as testosterone and dihydrotestosterone, while women have more female hormones such as estradiol. Testosterone is called an anabolic-androgenic hormone. “Anabolic” refers to how it uses substances and nutrients in the body to build muscle tissue. “Androgen” refers to the masculinizing properties such as strength, beard growth, aggression, formation of testicles, etc. Because women have fewer anabolic-androgenic hormones, they produce less muscle tissue during and after puberty than men, whose testosterone levels shoot up during that time. Untrained men therefore (normally) have more muscle mass than women, but also thicker, heavier, and longer bones, which further increases the difference in size. Data suggest that the greater strength of the men was due primarily to larger fibers. A.E. Miller, McMaster University 

Men have larger muscle fibers

Men have (most likely due to hormonal differences) more and larger muscle fibers. Researchers at McMaster University in Hamilton, Canada, studied the differences in strength between men and women, measured the size and numbers of muscle fibers, and looked for a correlation. They had participants train their biceps and quadriceps. Women had 52% of the strength of men in their arms and 66% in their legs. Men also had a larger size of muscle fibers corresponding to the difference in strength.

Data suggest that the greater strength of the men was due primarily to larger fibers. A.E. Miller, McMaster University 

“Men are tough, women are sexy”

In addition, the environment and upbringing also have a significant influence. Just look at the size of men now compared to the beginning of the last century. The idea that men “should be strong and tough” is a historical fact, whether it is important for finding food, finding a partner, or defending territory. However, the definition of “tough and strong” has changed. Since Eugene Sandow, the founder of modern bodybuilding, began not only doing strongman tricks but also exhibiting his physique as an attraction, the ideal image of a man has changed. Okay, it seemed to take a different turn with the emergence of the “metrosexual,” but that is now (fortunately) dying a slow death. Emancipation movements and female action figures have done little to change this difference in the perception of men and women. Although women nowadays no longer just play the victim or the damsel in distress in movies, but sometimes slaughter entire armies (Kill Bill, Suckerpunch, Tomb Raider, The Avengers, Elektra, etc.), they (again, fortunately) will never have the muscular physique of a Schwarzenegger in Conan or Stallone in Rambo. Although there are protests against emaciated models, being thin with curves in “the right places” remains the norm. Men and women often enter the gym with different goals, which has further increased the difference in muscle mass between men and women. These environmental factors are, of course, not always equal. Some boys like ballet, and some girls like soccer. The question is, therefore, to what extent the natural difference is abolished when a girl/woman trains exactly the same way as a man.

Response differs between men and strength training for women

Studies on the difference in muscle mass growth between men and women do not show a consistent picture. Some show a difference, others do not. However, the most important thing is that even in the studies showing that women can gain the same percentage of muscle mass as men, this still means that they gain less muscle mass in absolute terms. After all, adding 10% to a man’s arm of 40cm is more than 10% to a woman’s arm of 30cm. American researchers from the University of Maryland investigated the differences in response to strength training between men and women, young and old. They had 11 young men (aged 21-29), 11 young women (aged 23-28), 12 older men (aged 65-75), and 11 older women (aged 65-73) do strength training for the quadriceps. They trained one leg for nine weeks, three times a week using leg extensions. After this, they had 31 weeks of “detraining,” meaning they did not train during that period. The researchers measured the muscle size using MRI before and after the training. They found little difference between young and old. However, there were significant differences between men and women. In men, the size increased by an average of 204 cm3, while in women, it was slightly less than half, 101 cm3. This difference was also significant compared to the initial volume. After training, both lost most of the gained mass (men 151 cm3 and women 88cm3). After 31 months of “detraining,” it is noteworthy that some of the gains remained. However, researchers from the University of Georgia came to a completely different conclusion. They had seven men (ME) and eight women (FE) train their upper arms and thighs three times a week for 16 weeks. A third group of seven people served as a control group and did not train. They had men and women train elbow flexors and extensors (biceps and triceps) and knee flexors and extensors (quadriceps and hamstrings) at 70%-90% of maximal voluntary effort. Firstly, they found that women relatively gained more muscle strength through training than men, but this difference was not statistically significant (biceps 59.2% vs. 36.2%, triceps 41.7% vs. 32.6%, quadriceps 33.9% vs. 28.8%, and hamstrings 24.4% vs. 12.8%). Looking at muscle mass growth, they saw that in both cases, arm circumference increased by 7.9% and the cross-sectional area (bone plus muscle) increased by 17.5% for men and 20.4% for women. Looking solely at muscle mass (cross-sectional area without bone and fat), this increased by 15.9% for men and 22.8% for women. There was no significant increase in thigh circumference in either case, likely due to a decrease in fat. They concluded that men and women achieved relatively similar results with training.

We conclude that relative changes in strength and training are similar in men and women Kirk J. Cureton, University of Georgia

Researchers from the University of Massachusetts also examined the differences in muscle strength and size increase of the biceps between men and women but used a much larger population of 342 women and 243 men. They had them do progressive dynamic weight training (the most common form in a gym) for 12 weeks and measured the cross-sectional arm circumference and maximum strength (both isometric and dynamic) before and after. There were significant differences in the results between men and between women. The entire group’s circumference increased by -2% to 59% (-0.4 cm to 13.6 cm). The increase in maximum strength (the weight with which you can do one repetition) ranged from 0% to as much as 250%! With such huge differences within one group, it is questionable what differences between men and women mean in this context. They found a difference in size growth between men and women:

Additionally, men gained significantly more absolute and relative biceps CSA in the trained arm than women after 12 wk of training (relative gains of 20.4 vs 17.9% for men vs women, respectively.

A difference of 2.5% in this study is statistically relevant, but not impressive. In the chart above, you can see the percentage of growth in cross-sectional area of the biceps on the horizontal line and the percentage of people who achieved that growth (black=men, white=women). Also, in this study, the relative increase in strength for women was greater than for men:

Additionally, the interaction term (gender × time) determined a significantly greater relative gain in 1RM for women versus men after 12 wk of training (64.1 vs 39.8% for women vs men, respectively; P < 0.001), despite greater absolute gains in the men.

The researchers therefore concluded that the difference in increase in mass between men and women was smaller than the difference in increase in strength of women compared to men:

Men had only a slight advantage in relative size gains compared with women, whereas women outpaced men considerably in relative gains in strength.

Several studies have been conducted with different outcomes. In most cases, men gained slightly more muscle mass (both absolute and relative), while women often gained (relatively) more strength. The differences in muscle mass gain between the various studies are sometimes caused by not taking into account body fat percentage. For example, there is a study where the circumference of the thigh in women remained the same after weeks of training, but with less fat and more muscle. If in this case only the circumference had been measured, the conclusion would have been that the training had no effect, whereas it did. The main point here is that women do respond to strength training by muscle growth. However, since they have less muscle mass to begin with, this growth is smaller in absolute terms, so they will need to train more (and/or eat better) to compensate for this difference. The chance of a woman becoming as muscular as a typical bodybuilder is therefore very small when you realize how much effort a male bodybuilder has to put in.

Difference in muscle memory

Another notable point is the greater relative increase in strength. You might think this is due to muscle memory, or the neurological connection between the brain and the muscle. When you do a strength exercise for the first time, this connection strengthens quickly. As a result, your strength increases faster than the growth in muscle size would suggest. This is evidenced, among other things, by various studies on strength gain after imaginary training where the muscle is not actually used but still becomes stronger. Several studies have shown that the initial increase in strength comes from the neurological connection rather than larger muscle mass. You might suspect that men do strength training more often than women, so this connection is already strong, and the only strength increase comes from growing muscle mass, while women still benefit from the gained strength through this neurological connection. However, researchers from Massachusetts thought that this difference did not come from a difference in neurological response and referred to research by Moritani and De Vries. Moritani and De Vries’ research looked at the difference between men and women supposedly under equal conditions. However, my suspicion is that these conditions were not equal. There is a good chance that there were more men in the group who were already doing strength training than in the group of women, simply because men more often engage in strength training (until, of course, women worldwide flock to the gym in millions and kick the men away from the dumbbell corner after reading this article).

Strength Training for Women Leads to Higher Fat Burning

The main reasons women should “have to” do strength training is that by combining cardio with strength training, you may burn more fat. Almost always, losing weight is the primary reason for women to hit the gym. However, just as often, they wrongly think that strength training has no place in a schedule to achieve this goal. This is incorrect! Strength training increases your resting metabolism. In other words, the number of calories your body burns at rest increases. With the same diet, you will therefore lose more weight or store less fat (depending on whether you have a calorie surplus or deficit). High-intensity training like strength training also increases the amount of fat-burning hormones such as growth hormone and epinephrine.

First, high-intensity exercise training induces secretion of lipolytic [fat-burning] hormones including growth hormone and epinephrine, which may facilitate greater post-exercise energy expenditure and fat oxidation. Second, it has been reported that under equivalent levels of energy expenditure high-intensity exercise training favors a greater negative energy balance compared to low-intensity exercise training. B.A. Irving, University of Virginia

Higher Fat Burning

In this regard, it is important to know that your body has different types of muscle fibers that work in different ways for different purposes. If you train the so-called type I (“slow twitch”) muscle fibers, you train endurance as you do with moderate-intensity cardio. If you train at high intensity, such as sprinting or strength training, you train more the type II (“fast twitch”) muscle fibers. You use type I muscle fibers for low intensity over a long period and type II for high intensity over a short period. In the case of high intensity, the type I muscle fibers are used first for the initial load and then, when the muscle realizes it cannot handle the load differently, the (different types of) type II fibers. A theory for the added value of strength training for fat burning is the idea that the more muscle fibers you use, the more you burn. Researchers from the Boston University School of Medicine noted that in relation to what we know about the role of type I muscle fibers in metabolism, little is known about the role of type II muscle fibers in this process. In mice, they stimulated muscle growth by hypertrophy through activation of the transgene AKT1. Now, in one sentence, I probably mentioned 3 or 4 concepts that are unfamiliar, so here’s the explanation: Hypertrophy is the growth of muscles through the enlargement of muscle fibers. This mainly happens through protein synthesis, the conversion of amino acids into proteins that can be absorbed by the muscle cell. The AKT1 gene stimulates this protein synthesis. By activating an artificial AKT1 gene (transgene = artificial/modified gene) in mice, the researchers were able to cause larger muscle mass to see the consequences. After all, you can’t send a mouse to the gym with the instruction to perform certain resistance exercises (you can, but it yields very little data). The increase in muscle mass was mainly caused by the growth of type II muscle fibers, which also led to more muscle strength . However, the researchers also saw that the increase in type II muscle fibers resulted in increased oxidation of fatty acids, or increased burning of fatty acids. They therefore concluded that the increase in muscle mass through enlargement of type II muscle fibers can limit/reduce overweight and improve metabolism.

Our findings indicate that an increase in fast/glycolytic muscle mass can result in the regression of obesity and metabolic improvement through its ability to alter fatty acid oxidation in remote tissues. Y. Izumia, Boston University School of Medicine

You might now say: “Great for mice, but what about humans?”. Mice were used because artificial modification of the gene makes it easy to induce muscle mass growth. But let’s see how it goes with humans. For that, I’ll start in the U.S. where researchers from the University of Virginia had overweight women undergo cardio (vascular training) at low intensity (muscle fiber type I) or high intensity (muscle fiber type II). No strength training, but still relevant in this context because it involves the same type of muscle fibers as high-intensity strength training. 27 women were divided into three groups:

• 11 women did low intensity (“Low Intensity Exercise Training” – LIET), 5 days a week at an intensity where no lactate is produced (so low, only type I muscle fibers)
• 9 women did high intensity (HIET), 3 days a week at an intensity where lactate is produced (thus higher intensity and also type II muscle fibers) and 2 days a week at lower intensity as in the LIET group.
• 7 women in the control group who did not train (Control).

The training time was chosen so that in both test groups, 400 kilocalories were burned per session. Before and after the training period, the researchers looked at the amount of belly fat and the size of the thigh muscles in a (computer-generated) cross-section. The body fat percentage was calculated based on air displacement. Result and conclusion: High-intensity training significantly reduces the total amount of belly fat, while this did not happen in the other two groups (low intensity and the control group). They therefore concluded:

The present data indicate that body composition changes are affected by the intensity of exercise training with HIET more effectively for reducing total abdominal fat, subcutaneous abdominal fat, and AVF in obese women with the metabolic syndrome. B.A. Irving, University of Virginia

Okay, mice and high-intensity cardio, but what about strength training in humans?” is the question you might now rightfully ask. It’s nice that it involves the same type of muscle fibers, but you may only be truly convinced when the effect of strength training by humans on fat burning has been investigated. In Spain, as part of type 2 diabetes research, they studied the effect of strength training on belly fat. They concluded, among other things, that strength training, twice a week and without following a concurrent calorie-restricted diet, leads to accelerated fat breakdown and a decrease in belly fat.

Two sessions per week of PRT, without a concomitant weight loss diet, significantly improves insulin sensitivity and fasting glycemia and decreases abdominal fat… J. Ibañez, Research and Sports Medicine Center, Government of Navarra

That they did not follow a diet would mean that they ate too much to lose weight, but not so much that it negated the effect of strength training on fat burning.

More fat loss by cardio or strength training for women?

There have been several studies comparing the effects of strength training and cardio on fat loss. Unfortunately, there are many different outcomes. The most drawn conclusion is that you lose more fat through cardiovascular training than through strength training. The same uncertainty exists about whether a combination of cardio and strength training is better than strength training alone. The problem with these studies is that often the results days, weeks, or even months after stopping training have not been considered. Strength training results in longer fat loss after training stops due to increased lean mass and thus increased BMR (Basal metabolic rate), digestion at rest. Researchers from the University of Sydney reviewed the outcomes of various studies that looked at the influence of both strength training and cardio. I could discuss all other studies including those compared by the researchers in Sydney, but the fact that there is uncertainty about it at least says the following: Both cardio and strength training have been shown in various studies to contribute to fat loss. The total of studies shows a slight preference for cardio. Cardio, however, does not provide additional muscle strength, and the effect is shorter-term. In addition, it offers more variety in training to do both cardio and strength training during a workout instead of cycling for an hour. By doing both cardio and strength training for fat loss, you not only lose weight, maintain this fat loss for a longer period, and have more variation, but you also benefit from the main effect of strength training, an increase in strength (duh).

Bodybuilding for Women

“But what about those heavily muscled women where in some cases you can only see from the makeup that it’s a woman?” you might be asking now. Firstly, there’s strength training and strength training, and then there’s bodybuilding and bodybuilding. What I mean by that is that within those concepts, there are incredibly many variations in intensity, motivation, effort, goals, and means. In one of the studies mentioned above, strength training was done using bands. For the seasoned strength athlete, that’s, to put it mildly, “strength training-light”. There’s a big difference between strength training aimed at muscle mass and strength training aimed at strength and health. Training for muscle mass often involves fewer repetitions (often pyramid: e.g., 15, 12, 8, 6 repetitions) with relatively heavy (in the case of pyramid, increasing) weights. Training for strength for health is often done through specific exercises focused on mobility and stabilization with lighter weights and more repetitions. Nutrition is also different, as for muscle mass, you ensure you get enough nutrients while most people generally try to lose weight by eating less. The term strength training that I used here is actually not correct. The correct term is neuromuscular training, training where the emphasis is on stimulating/activating the muscle. This can thus be strength training, which, as the word suggests, is aimed at strength. However, it can also be training for muscle mass. When you start neuromuscular training, it’s important to keep your goal in mind and know how to focus your training on it. That doesn’t mean that you don’t develop strength with muscle mass training and vice versa, but the emphasis is different.

Number of Repetitions and Weight Have More Influence on Effect on Muscle Mass, Condition, or Strength Than Type of Exercise

The programs I’ve created, aimed at muscle mass, can also be used by women. The only adjustment they need to make if muscle mass is not the priority is to adjust the number of repetitions mentioned to, for example, 15-20 repetitions per set (with a weight that you can just manage this number with). This, for example, provides more muscle condition. If the aim is to increase maximal strength, you do fewer repetitions (e.g., 6 or fewer) with more weight. Here, the chance of an increase in muscle mass is greater than with the high number of repetitions aimed at muscle condition.

“Male Women”

Female bodybuilders specifically focus their training on developing muscle mass. This is a choice and not an automatic consequence of strength training in general. By “choice” I mean, among other things, the number of repetitions per set, the muscle groups trained, but especially the nutrition focused on muscle mass. In addition, there’s another choice: Natural or chemical? By “chemical” is meant: “The use of Anabolic-androgenic steroids (AAS), growth hormones, and other types of doping”. Natural bodybuilding means that you do not use these performance-enhancing substances, although this does not necessarily mean that you do not use supplements such as protein and creatine (which is something completely different!!). Mention is sometimes made about male bodybuilders, “If they look like a bodybuilder, then they use steroids”. I don’t fully agree with this because I am myself a natural bodybuilder and am also regularly mistaken for a user. However, when I look around me in the gym and think about who I know uses, I have to admit that this is often the case (also in many cases where someone does not look like a bodybuilder at all). Looking at professional bodybuilders in the IFBB (International Federation of Bodybuilders), it’s widely known that they all use AAS. I started this piece with the explanation that the difference in muscle mass between men and women is mainly caused by differences in hormonal balance. For a woman, there’s only one way to have a physique comparable to that of highly trained men. Namely, by eliminating this difference by changing their own hormonal balance through anabolic-androgenic (tissue-building and masculinizing) hormones such as testosterone and its derivatives. So, if you see a photo of a woman like Iris Kyle, (8-time Ms. Olympia! see image above) realize that:

• This woman dedicates everything, absolutely everything in her life to become as muscular as possible.
• Every meal, every workout is aimed at becoming the most muscular woman in the world.
• She has to use steroids for this that are even more dangerous for women than for men (and therefore also used in smaller quantities).
• Many men in their wildest dreams cannot achieve looking like this.

So, trust me when I say that a lot has to happen before you as a woman become “too muscular”.

Miss Figure, Miss Fitness, Miss Bikini

In addition to female bodybuilders, you have the ladies who participate in miss figure/fitness and miss bikini contests. These are more likely the examples that women would probably like to mirror themselves with. These women often train just as often and hard as professional bodybuilders and are just as obsessively involved in nutrition. Especially in the U.S., there’s a large industry in which these ladies operate from stages to photoshoots. In the photo above, you see Erin Stern, the winner of the miss figure election during the prestigious Olympia weekend 2012. I’m not saying that these women don’t use prohibited substances. However, if they do, it’s more likely to burn fat faster than to build more muscle mass. On the right, you see Silvana Joghi, whom I photographed not only during the shoot but also during her participation in the bikini-fitness class where the ladies should be less muscular than in the figure class. I can imagine that the requirements for the bikini-fitness class correspond to how most ladies would prefer to see themselves. As mentioned earlier, Silvana has not achieved this physique by doing cardio alone, but by emphasizing strength training . By the way, I recently covered the topic of “bodybuilding for women” more extensively in the third part of the series “The Stigma of Bodybuilding”.

Conclusion

Strength training offers only benefits for women. The fear of becoming very muscular is unfounded. Women can grow in muscle mass through strength training, but due to hormonal differences with men, they will not have the appearance of a bodybuilder. Strength training helps in losing fat. Although cardio probably delivers results faster, you benefit longer from lost fat through strength training. In addition, you benefit from the gained strength. A woman will only look like a bodybuilder when she, in addition to intensive training and careful nutrition, uses steroids for this. The results of the same training and dedication to correct nutrition, but without muscle-enhancing substances, can be seen in women participating in miss figure contests.

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