Effects of oral contraceptive use on muscle strength, muscle thickness, and fiber size and composition in young women undergoing 12 weeks of strength training: a cohort study

Eun-Sook Sung; Ahreum Han; Timo Hinrichs; Matthias Vorgerd; Petra Platen

doi:10.1186/s12905-022-01740-y

Effects of oral contraceptive use on muscle strength, muscle thickness, and fiber size and composition in young women undergoing 12 weeks of strength training: a cohort study

BMC Womens Health. 2022 May 10;22(1):150. doi: 10.1186/s12905-022-01740-y.

Authors

Eun-Sook Sung^{1

2}, Ahreum Han², Timo Hinrichs^{2

3}, Matthias Vorgerd⁴, Petra Platen⁵

Affiliations

¹ Department of Physical Education, Korea University, Seoul, Republic of Korea.
² Department of Sports Medicine and Sports Nutrition, Faculty of Sport Science, Ruhr-University Bochum, Gesundheitscampus Nord, Haus 10, 44801, Bochum, Germany.
³ Division of Sports and Exercise Medicine, Department of Sport, Exercise and Health, University of Basel, Basel, Switzerland.
⁴ Department of Neurology, Kliniken Bergmannsheil, Ruhr-University Bochum, Bochum, Germany.
⁵ Department of Sports Medicine and Sports Nutrition, Faculty of Sport Science, Ruhr-University Bochum, Gesundheitscampus Nord, Haus 10, 44801, Bochum, Germany. Petra.Platen@rub.de.

Abstract

Background: It is suspected that hormonal fluctuations during menstruation may cause different responses to strength training in women who use oral contraceptives (OC) versus those who do not. However, previous studies that investigated the existence of such differences produced conflicting results. In this study, we hypothesized that OC use has no effect on muscle strength and hypertrophy among women undergoing strength training. Thus, we compared the differences in muscle strength and thickness among women who used OCs and those who did not.

Methods: We investigated the influence of OC use on muscle strength (F_max), muscle thickness (Mtk), type 1-to-type 2 muscle fiber (NO) ratio, muscle fiber thickness (MFT), and nuclear-to-fiber (N/F) ratio. Seventy-four healthy young women (including 34 who used OCs and 40 who did not) underwent 12 weeks of submaximal strength training, after which F_max was evaluated using a leg-press machine with a combined force and load cell, while Mtk was measured using real-time ultrasonography. Moreover, the NO ratio, MFT, and N/F ratio were evaluated using muscle needle biopsies.

Results: Participants in the non-OC and OC groups experienced increases in F_max (+ 23.30 ± 10.82 kg and + 28.02 ± 11.50 kg respectively, p = 0.073), Mtk (+ 0.48 ± 0.47 cm² and + 0.50 ± 0.44 cm² respectively, p = 0.888), F_max/Mtk (+ 2.78 ± 1.93 kg/cm² and + 3.32 ± 2.37 kg/cm² respectively, p = 0.285), NO ratio (type 2 fibers: + 1.86 ± 6.49% and - 4.17 ± 9.48% respectively, p = 0.169), MFT (type 2 fibers: + 7.15 ± 7.50 µm and + 4.07 ± 9.30 µm respectively, p = 0.435), and N/F ratio (+ 0.61 ± 1.02 and + 0.15 ± 0.97 respectively, p = 0.866) after training. There were no significant differences between the non-OC and OC groups in any of these parameters (p > 0.05).

Conclusions: The effects of 12 weeks of strength training on F_max, muscle thickness, muscle fiber size, and composition were similar in young women irrespective of their OC use.

Keywords: Birth control pill; Menstrual cycle; Muscle fiber distribution; Resistance training.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Cohort Studies
Contraceptives, Oral / therapeutic use
Female
Humans
Male
Muscle Strength / physiology
Muscles
Resistance Training*

Substances

Contraceptives, Oral