Participants sought for studies Would you like to participate in a training study about the impact of the menstrual cycle on physical performance?

Many sporting women, at both the recreational and elite level believe that the menstrual cycle affects their training and competitive performance. Many women have therefore tried to periodize their training in relation to the menstrual cycle to improve the training effect. However, there are still very few studies that have clearly shown whether or in what way the training regimen should be adapted to the menstrual cycle.

Weight Training. Photo: Pixabay.

Researchers at Karolinska Institutet are now looking for participants to study the effect on physical performance after different training regimens during three consecutive menstrual cycles.

Who can participate?

We are looking for females between the ages of 18 and 35, who have a regular menstrual cycle and do not use any hormonal contraceptives. You should be used to training at least three times per week, but not be active at an elite level.

How does the study work?

If you agree to participate, you will be included in one of three groups that will train based on three different ways of periodizing training according to the menstrual cycle. The training in all groups will consist of both cardio and strength training and will be carried out at Friskis och Svettis gyms in Stockholm. You will be drawn into one of the following groups:

Group 1: This group will concentrate training on the first two weeks of the menstrual cycle. During these weeks, participants in this group will train 5 times/week. For the remainder of the menstrual cycle, training is reduced to once per week.
Group 2: This group will train once per week during the first two weeks of the menstrual cycle, then train 5 times/week during the remaining two weeks.
Group 3: This group exercises three times per week throughout the study period (throughout the menstrual cycle).

Before and after the training period, you will go through a health check and submit blood samples for analysis of hormones. Before and after the training period, you will complete physical performance tests for fitness and strength. Examination of body composition (body fat content and muscle mass) will be carried out with so-called DXA measurement.

Throughout the study period, you will wear an OURA ring that measures your daily activity and sleep patterns. The OURA ring is yours to keep after completion of the study. 

Contact details

Researcher and contact person

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Linda Ekenros

Assistant Senior Lecturer

Responsible researchers for the study

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Cecilia Fridén

Affiliated to Teaching/Tutoring;Affiliated to Research

Processing of personal data

Your personal data is processed for the purposes of this study in accordance with GDPR (General Data Protection Regulation). The legal entity responsible for processing of your personal data is Karolinska Institutet. The Data Protection Officer can be reached at The data will be analyzed on a group level, handled confidentially and it will be stored in a secure database at Karolinska Institutet. You can terminate your participation in the study at any time.