The Effects of Strength Training on Women
In this the first of several summaries of research into the effects of strength training for women we will address some key issues such as can women make increases in strength? Will strength training make women bigger? and more.
Fortunately, there is a significant amount of research on the gender differentiated responses to strength (resistance) training. We will refer to some of the key points from several such studies in this article.
Can women increase strength?
There are many different studies on this subject but there is a recent investigation by Martel and colleagues from the University of Maryland (2006) that investigated responses to strength training in both genders and two different age groups. These groups included men and women aged 20-30, and men and women aged 65-75. All subjects trained over a nine week period, three times per week. Martel, et al. concluded that, “…strength training led to significant increases in 1 repetition maximum and type II fibre cross-sectional area in all groups.”
Irrespective of age or gender, subjects saw increases in fast twitch muscle group size and correspondingly, all groups saw increases in power. This shows that it is certainly possible for women to see real results from strength training and they can continue to enjoy some of these benefits at any age.
Will women reach a point where they are too old to make improvements in strength?
To explore the question of potential age limitations in women strength trainers we will refer to a study done by Dr. Dawn Skelton and colleagues at the University of London (1995). They studied older women with an age range of 76-93. 20 subjects strength trained three times per week using three sets of 4-8 repetition maximum (RM). The study concluded, “Progressive resistance exercise can produce substantial increases in muscle strength and in power standardized for body weight in healthy very old women.”
This supports the earlier findings of Charette, et al. (1991) from Stanford University. Over their twelve week study, they showed that women aged 69-70 could not only safely strength train but would also see increases in strength and size of fast twitch muscle fibres.
Can strength training help reduce body fat levels?
It would seem clear that age is not a significant limiting factor for women to benefit from strength training. However, one potential ‘benefit’ that some women often express concerns about is related to increases in size. A study from Ohio University by Staron, et al. (1990) lasted over twenty weeks with twenty four women training twice per week using three sets of 6-8RM. Interestingly, whilst the subjects showed increases in lean body mass (i.e. muscle weight) they also saw a decrease in body fat percentages. The net result was no change in thigh girth measurements. Even when using heavy strength training protocols, there were no increases in size observed. For those women who remain unconvinced – it is worth remembering the law of reversibility. Namely, if strength training is stopped then muscles will reduce in size (atrophy) and this cannot ‘turn into fat’ no matter which myth is being presented. Strength training can be viewed as a no-risk when it comes to size; simply stop strength training if you feel you really have gained too much muscular size.
Will strength training make women bigger?
This brings us to a consideration of the differences in responses to strength training between the genders. Ivey, et al. (2000) conveys that whilst their subjects were able to increase muscle mass irrespective of age, the male subjects saw increases in muscle mass that were “about twice” that of their female counterparts. Thus, no matter how hard women strength training it is extraordinarily unlikely that they will see similar muscular adaptations which match those of men – this is likely to be good news for most female strength trainers (but not all!).
In summary, let’s review the initial questions with their corresponding answers;
- Can women make increases in strength? – Answer: yes
- Will women reach a point where they are too old to make improvements in strength? – Answer: no
- Can strength training help reduce body fat levels? – Answer: yes
- Will strength training make women bigger? – Answer: no
We will consider the specific health benefits achieved by strength training for women in my next article.
Charette SL, McEvoy L, Pyka G, Snow-Harter C, Guido D, Wiswell RA, Marcus R (1991) Muscle hypertrophy response to resistance training in older women. Journal of Applied Physiology May 1991 vol. 70, no. 5
Ivery FM, Roth SM, Ferrell RE, Tracy BL, Lemmer JT, Hurlbut DE, Martel GF, Siegle EL, Fozard JL, Jeffrey Metter E, Fleg JL, Hurley BF (2000) Effects of age, gender, and myostatin genotype on the hypertrophic response to heavy resistance strength training. The Journals of Gerontology, Biological Sciences and Medical Sciences November 2000 vol.55, no.11 p641-8
Martel GF, Roth SM, Ivey FM, Lemmer JT, Tracy BL, Hurlburt DE, Metter EJ, Hurley BF, Rogers MA (2006) Age and sex affect human muscle fibre adaptations to heavy-resistance strength training. Experimental Physiology March 2006 vol.91 no.2 p457-64
Skelton DA, Young A, Greig CA, Malbut KE (1995) Effects of resistance training on strength, power, and selected functional abilities of women aged 75 and older. The Journal of the American Geriatrics Society October 1995 vol.43 no.10, p1081-7
Staron RS, Malicky ES, Leonardi MJ, Falkel JE, Hagerman FC, Dudley GA (1990) Muscle hypertrophy and fast fibre type conversions in heavy resistance-trained women. European Journal of Applied Physiology and Occupational Physiology vol.60, no.1 p71-9
International Director of Education and Training