Tuesday, July 3, 2012

Baby Weight and Depression? It Doesn't Have to be the Treadmill: 11% and 8% Less Body Fat with Resistance and Flexibility Training Within 4 Months Postpartum

Image 1 (ezineMarks.com): Heidi Klum certainly deserves respect to go from left to right within 5 weeks, but not every woman has a fitness trainers and chefs to make that possible.
I know, this may not be a "regular" SuppVersity post; and no, I am not becoming a father, but I still found that the results of a recently conducted trial by J. D. LeCheminant et al. from the Brigham Young University in Provo, Utah, deserved some attention. After all you will usually be confronted with the notion that those celebrity moms run around for (or four?) hours every day to starve themselves back into their size zero jeans within possibly record-braking time (see "The German Fräuleinwunder", Heid Klum in image 1). In fact, breastfeeding alone is associated with a ~618 kcal increase in energy expenditure per day alone would be way above my usual recommendation not to go below a -20% reduction in calorie intake, when you are dieting in order to preserve precious muscle tissue, and should thus well suffice to get you my dear mothers back in shape in no time, even if you did not work out, at all (Thomson. 1970).

Do it like Heidi: Breastfeed and lift weights, as long your baby is still too light to be lifted ;-)

Six weeks after they had given birth and thus way later than Heidi Klum, for example, the young mothers (mean age: 26 years) who had been recruited by LeCheminat and his colleagues from the local community were randomized to one out of two study groups:
    Does resistance training increase fertility I guess, this has little to no statistical significance, but upon reviewing the 'collateral' data from the study, I realized that 10% of the women in the RT group withdrew from the study due to another pregnancy. In the FT group, on the other hand it was not a single one. Probably just coincidence (or a side effect of feeling strong and sex?), but interesting, nonetheless ;-)
  1. resistance training (RT) - nine exercises (leg extension, seated leg curl, leg press, biceps curl, shoulder press, chest press, lat pull-down, seated row, and abdominal curl-ups) for all major muscle groups, 1–3 sets per exercise (increasing from month 1-4), 90-s rest interval between sets, and 8–12 repetitions per set performed on 2 nonconsecutive
    days per week at a local physical therapy
  2. flexibility training (FT) - the protocol was based on the recommendations from the American College of Sports Medicine Position Stand (1998) and included static stretching, four stretches (sets) per major muscle group, and holding each stretch for 10–30s; participation in group stretching once per week was optional
At baseline, 2 months, and 4 months, all participants were tested for strength, flexibility, exercise self-efficacy, depressive symptoms, and objectively measured PA. Body composition (DXA) was assessed at baseline and 4 months. Another parameter that may well be of interest yet was not included in the later  statistical analysis is the breast feeding rate, of which the scientists state that despite the fact that "most" (95%) were breastfeeding, only...
56% were breastfeeding exclusively, 33% combined infant formula with breastfeeding, and 7% combined some solids with breastfeeding. The remaining two participants did not report the extent of breastfeeding combined with formula or solids.
Obviously the statistical power would have been too low for significant results here, anyway, but I would still have been interested if there was - as I would speculate a certain trend for "exclusive breast feeders" to lose their 16kg of pregnancy weight faster than their "formula assisted" peers.
Figure 1: Changes in body composition from begin to the end of the study period (based on LeCheminan. 2012)
Apropos losing weight, as the data in figure 1 clearly indicates that worked almost magically for women in both groups.Although the changes are obviously slightly more pronounced and despite the fact that the women in the RT group quadrupled (+300%!) the amount of vigorous activity they performed on a weekly basis while the women in the FT group increased their vigorous activity levels by "only" 50%, these differences did not reach statistical significance. This does yet not mean that someone who strength trains cannot see better results (especially in the mirror) compared to someone who is just doing some stretches, it does however underline how returning to normal eating habits staying generally active and not sitting depressed next to your child and in front of the television all day long alone, can already help you, your wife, friend or relative get rid of much (~60%) of the 6.5kg the women in the stud had retained of their 16kg of pregnancy weight even postpartum in only 4 months.
Image 2 (TopNews.in): Light resistance training is good for mothers to be and  has no detrimental effects on unborn children.
Working out during pregnancy? Contrary to common believe, a light to moderate strength training workout (35-40min) performed three times per week over the second and third trimester of pregnancy does not have a negative impact on the newborn's body size or overall health (Barakat. 2009). On the contrary, it could help "attenuate the adverse consequences of maternal body weight gain" (Barakat. 2009) and "eliminate or significantly reduce the need for insulin in women with GDM [gestational diabetes]" (Brankston. 2003) - prepartum obesity prevention for you and your child, what more can you ask for, ladies?
Moreover, the women in the RT group however had so profound strength increases, especially in the midsection, that they probably could not only keep pace with, but have probably easy surpassed the weight development of their infants.
Figure 2: Strength development (rel. change vs. baselin) during the 4-months study period (based on LeCheminan. 2012)
What's the use of that? Well aside from probably being stronger (and sexier) than before the pregnancy the fortified midsection, will safeguard these mothers from the dreaded backaches, many of them develop as a consequence of carrying their increasingly heavier toddlers around. Against that a couple of pounds of body fat less may eventually reveal a set of chiseled abs is nothing but a welcome side effect of which I personally feel that it is not absolutely necessary for a woman.

Bottom line: If you want to get in shape after a pregnancy,...

Image 3 (MusclePharm): Regardless of what you think about their products. MusclePharm's advertising guys certainly have their finger on the pulse of the time: A time, where the previous perception of skinny women = sexy women begins to tumble - if you asked me, I'd say it was about time for that to happen! Strong is the new sexy (baby?)!
It is not necessary to starve yourself and your baby (you can hardly expect to have enough breast milk on a low-fat 800kcal diet, can you?) hand it over to granny and do 4h on the treadmill every day. You better get yourself a gym membership, find new friends and train your whole body at least two times a week. That will not only make your mother (or mother-in-law) your toddler and husband happy it will also help you to come to terms with your new self, which - if you do it correctly - will be stronger, healthier, sexier and happier than before, as a side-finding of the study was that the "sedentary time and light-intensity PA time improved to a greater extent in the RT group than the FT group" indicating that resistance training, but not flexibility training "would result in improved confidence to perform PA following childbirth and perhaps facilitate behavioral change toward a sustained increase in spontaneous PA" (LeCheminant. 2012) as it was proposed by Schmitz et al in another context (Schmitz. 2003) and could thus have exponentiated the direct effects of strength training by indirect / downstream effects which counteract the general tendency towards a sedentary, non-active lifestyle in our society.

  1. Barakat R, Lucia A, Ruiz JR. Resistance exercise training during pregnancy and newborn's birth size: a randomised controlled trial. Int J Obes (Lond). 2009 Sep;33(9):1048-57. Epub 2009 Jul 28.
  2. Brankston GN, Mitchell BF, Ryan EA, Okun NB. Resistance exercise decreases the need for insulin in overweight women with gestational diabetes mellitus. Am J Obstet Gynecol. 2004 Jan;190(1):188-93.
  3. Lecheminant JD, Hinman T, Pratt KB, Earl N, Bailey BW, Thackeray R, Tucker LA. Effect of resistance training on body composition, self-efficacy, depression, and activity in postpartum women. Scand J Med Sci Sports. 2012 Jun 28.
  4. Schmitz KH, Jensen MD, Kugler KC, Jeffery RW, Leon AS. Strength training for obesity prevention in midlife women. Int J Obes Relat Metab Disord. 2003 Mar;27(3):326-33.
  5. Thomson AM, Hytten FE, Billewicz WZ. The energy cost of human lactation. Br J Nutr. 1970 Jun;24(2):565-72.