This study is designed to determine whether time-of-day and menstrual cycle phase influence athletic performance and is expected to contribute valuable insight into how both time-of-day, and hormonal factors can influence performance and expand existing research. This study aims to support more inclusive, effective and personalised approaches to training and competition schedules for female athletes.
The study will involve two testing days that require a participant to complete a compilation of tests at 07:00, 12:00 and 18:00 hours. The testing days will be arranged for when a participant is in phase 1 (lowest levels of progesterone in the menstrual cycle) and phase 4 (highest level of progesterone in the menstrual cycle). The tests will examine a participant's executive function and physical strength.
This study will aim to recruit thirty 18-30-year-old females from Lancaster University who identify with a sport that they train \~3 times a week for with a purpose to compete. The females recruited must have a regular menstrual cycle and no history of sleep disorders.
Aim: To investigate the effects of time-of-day and menstrual cycle phase (low and high progesterone levels) on executive function and strength in females.
Objectives:
1. To determine the effects of time-of-day on executive function and strength tests. 2. To determine the effects of menstrual cycle phase on executive function and strength tests. 3. To examine if there is an interaction between time-of-day and menstrual cycle phase on executive function and strength tests.
Female (assigned at birth)
Aged 18-30 years
Tier 2 athlete which requires the participants to identify with a specific sport, train with a purpose to compete, regularly train ~3 times per week and compete at a local level (for example being a member of a BUCS sport and competing regularly with that sport)
Regular menstrual cycle - considered between 21-35-day cycles with at least 9 periods a year.
The current/previous (in the last 3 months) use of any contraceptive method that alter the menstrual cycle
The use of the emergency contraceptive pill either 3 months prior to the study or during the study
Diagnosis of menstrual disorders including (but not exclusively) endometriosis and Polycystic Ovary Syndrome (PCOS)
A formal diagnosis of sleep disorders such as insomnia
Participants will be selected from across Lancaster University (staff and students)
Cohort
Prospective
Not listed
Change in muscle strength with time-of-day and menstrual cycle phase
Repeated measures of strength at 07:00, 12:00 and 18:00 hours in phase 1 and 4 of the menstrual cycle. Handgrip strength requires participants to maximally squeeze the dynamometer for 3-seconds. 3 repeats will be carried out with the participants dominant hand, with 1-minutes of rest between each, recording the maximal values to determine both peak and mean values. Participants would also perform both countermovement and squat jumps, measuring flight time (seconds) and vertical jump height (centimetres). Each jump type will be repeated 3 times with a rest interval of 30-seconds between each jump repetition and a 2-minute rest interval between jump types. Maximal isometric Voluntary contraction of knee extensors and flexors would be measured over 4-seconds at 60° flexion. Between away and towards contractions, participants will have 30-seconds and between each set, they will have 3-minutes passive recovery.
Change in cognitive performance with time-of-day and menstrual cycle phase
Repeated measures of cognitive performance at 07:00, 12:00 and 18:00 hours across phase 1 and 4 of the menstrual cycle. It will be assessed with a modified Eriksen Flanker task. The task is a measure of inhibition and cognitive flexibility asking participants to respond to a visual stimulus depending on what is displayed on the screen and the instructions given. This modified flanker task uses arrows displayed on a screen and asking participants to focus on the central arrow that is flanked by arrows to its left and right, either congruent or incongruent to the central arrow. Section 1 of the task assesses simple reaction time whilst section 2 assesses inhibition and cognitive flexibility. Reaction time and number of correct answers for congruent and incongruent sequences will be determined and analysed as an indicator of cognitive flexibility and inhibition (two measures of executive function).
Change in menstrual cycle symptoms with time-of-day and menstrual cycle phase
During testing visits, questions will be asked regarding participants current menstrual symptoms to determine what affects their current phase of the menstrual cycle could be having on them. The questionnaire during testing will be repeated at 07:00, 12:00 and 18:00 hours across phase 1 and phase 4 of the menstrual cycle.
Ovulation phase confirmation
Participants will be asked to use ovulation strips three days before they are expected to ovulate and confirm with the researcher when they have had the positive test. They will carry out ovulation testing for two consecutive cycles of their menstrual cycle and report these both to the researcher. This study requires two testing visits to the lab, one when progesterone levels are at their lowest (during your period days 1-5) and one when progesterone levels are at their highest (just after ovulation typically around day 19-21). Participants will be asked to track their menstrual cycle on an app so that the researcher can arrange testing day visits.
Change in participant weight with time-of-day and menstrual cycle phase
Participants weight (kilograms) will be taken at each visit to provide information about weight fluctuation across the menstrual cycle phases and time-of-day.
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Lancaster University
Lead sponsor
Liverpool John Moores University
Collaborator
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