Search Results

You are looking at 1 - 10 of 82 items for :

  • "menstrual cycle" x
Clear All
Restricted access

Paola Rodriguez-Giustiniani and Stuart D.R. Galloway

state and replacing lost fluids on cessation of exercise is recommended; however, most of the research on this field has been done in males due to the uncertainty of including females in relation to menstrual cycle phase effects on fluid balance. Many factors affect fluid balance and rehydration, such

Restricted access

Daniel Martin, Craig Sale, Simon B. Cooper and Kirsty J. Elliott-Sale

Alterations to the female reproductive-axis influence health and athletic performance. 1 – 3 Between menarche and menopause, non-hormonal-contraceptive (non-HC) users typically have a monthly menstrual cycle, with a cyclical rise and fall in sex hormone concentrations. 4 Primary dysmenorrhea

Restricted access

David R. Bell, Megan P. Myrick, J. Troy Blackburn, Sandra J. Shultz, Kevin M. Guskiewicz and Darin A. Padua

Context:

Preventing noncontact ACL injuries has been a major focus of athletic trainers and researchers. One factor that may influence female noncontact ACL injury is the fluctuating concentrations of hormones in the body.

Objective:

To determine whether muscle properties change across the menstrual cycle.

Design:

Repeated measures. Testing was performed within 3 d after the onset of menses and ovulation. Repeated-measures ANOVAs were used to determine changes in variables across the menstrual cycle, and Pearson correlations were used to determine relationships between variables.

Participants:

8 women with normal menstrual cycles.

Main Outcome Measures:

Active hamstring stiffness and hamstring extensibility.

Results:

Hamstring extensibility (P = .003) increased at the ovulation testing session but hamstring muscle stiffness (P = .66) did not.

Conclusions:

The results indicate that hamstring muscle stiffness did not change across the menstrual cycle and hamstring extensibility increased at ovulation, when estrogen concentration increases.

Restricted access

Rebecca T. McLay, Christine D. Thomson, Sheila M. Williams and Nancy J. Rehrer

This study compared 3 d of carbohydrate loading (CHOL; 8.4 g·kg−1·d−1 carbohydrate) in female eumenorrheic athletes with 3 d of an isoenergetic normal diet (NORM; 5.2 g·kg−1·d−1 carbohydrate) and examined the effect of menstrual-cycle phase on performance, muscle-glycogen concentration [glyc], and substrate utilization. Nine moderately trained eumenorrheic women cycled in an intermittent protocol varying in intensity from 45% to 75% VO2max for 75 min, followed by a 16-km time trial at the midfollicular (MF) and midluteal (ML) phases of the menstrual cycle on NORM and CHOL. Time-trial performance was not affected by diet (CHOL 26.10 ± 1.04 min, NORM 26.16 ± 1.35 min; P = 0.494) or menstrual-cycle phase (MF 26.05 ± 1.10 min, ML 26.23 ± 1.33 min; P = 0.370). Resting [glyc] was lowest in the MF phase after NORM (575 ± 145 mmol·kg−1·dw−1), compared with the MF phase after CHOL (728 mmol·kg−1·dw−1) and the ML phase after CHOL and NORM (756 and 771 mmol·kg−1·dw−1, respectively). No effect of phase on substrate utilization during exercise was observed. These data support previous observations of greater resting [glyc] in the ML than the MF phase of the menstrual cycle and suggest that lower glycogen storage in the MF phase can be overcome by carbohydrate loading.

Restricted access

Anthony C. Hackney, Mary Ann McCracken-Compton and Barbara Ainsworth

This study examined substrate metabolism responses of eumenorrheic women to different intensities of submaximai exercise at the midfollicular (MF) and the midluteal (ML) phases of the menstrual cycle. Nine women performed a 30-min treadmill run in which the exercise intensity was made more difficult every 10 min (35%, 60%, and 75%). Carbohydrate (CHO) utilization and oxidation rates for the 35% and 60% intensities during the ML session were significantly lower than during the comparable intensities in the MF. Conversely, lipid utilization and oxidation were significantly greater during the 35% and 60% ML session than in the MF session. At 75%, however, the ML and MF CHO-lipid utilization and oxidation rates were not significantly different from one another. Thus, the phase of the menstrual cycle in eumenorrheic women does influence metabolic substrate usage during low- to moderate-intensity submaximai exercise, probably due to changes in the endogenous levels of the female sex hormones.

Restricted access

Travis Anderson, Sandra J. Shultz, Nancy I. Williams, Ellen Casey, Zachary Kincaid, Jay L. Lieberman and Laurie Wideman

, & Apel, 2004 ), has focused attention on the sex-specific differences in patterns of hormonal secretion as a potential factor in injury risk. Within this scope, prominent sex hormones (e.g., estrogen and progesterone) have received much attention, but other menstrual cycle–related hormones have been

Restricted access

Sigridur Lara Gudmundsdottir, W. Dana Flanders and Liv Berit Augestad

Background:

Menstrual dysfunctions are often found in athletic women. This study evaluated the association between leisure time physical activity (LTPA) and menstrual function in healthy nonathletic women.

Methods:

During 1984–1986, a populationbased health survey (HUNT 1) was conducted in Nord-Trøndelag, Norway, with follow-up (HUNT 2) in 1995–1997. Women < 45 years old in HUNT 2 were included in the current study. LTPA was assessed by questionnaire in HUNT 1 and HUNT 2, and menstrual function by questionnaire in HUNT 2.

Results:

Adjusted odds ratios (OR’s) for long cycles were increased in women who reported < 1 hour of light LTPA (OR = 1.4, 95% CI = 1.0–2.0) and 1–2 hours (OR = 1.3, 95% CI = 1.0–1.8) per week compared with women with ≥ 3 hours/week. Adjusted OR for irregular cycles was decreased in women constantly in the lowest tertile of LTPA index in HUNT 1 and HUNT 2 (OR = 0.4, 95% CI = 0.2–0.9). Adjusted OR for prolonged bleeding was 2.6 (95% CI = 1.3–5.4) for women with < 1 hour/week of light LTPA and 2.3 (95% CI = 1.3–4.3) for women with 1–2 hours, compared with ≥ 3 hours/week.

Conclusions:

Very low physical activity may increase the risk of menstrual cycle disruptions. Moderate PA should be encouraged for optimum reproductive health.

Restricted access

D.R. Paul, S.M. Mulroy, J.A. Horner, K.A. Jacobs and D.R. Lamb

The effects of employing a high-carbohydrate diet (carbohydrate-loading) to increase glycogen storage in skeletal muscle are not well established in female athletes. On 4 occasions—2 familiarization trials and 2 experimental trials—6 well-trained female subjects completed 6 × 15-min continuous intervals of cycling (12 min at 72% V̇O2max, 1 min at maximal effort, and 2 min at 50% V̇O2max), followed by a time trial 15 min later. The women consumed their habitual diets (HD; 6–7 g carbohydrate/kg lean body mass) for 3 days after the second familiarization trial and before the first experimental trial. During the 3 days following the first experimental trial, the subjects consumed a high-carbohydrate diet (CD; 9–10 g carbohydrate/kg lean body mass) prior to the second experimental trial. Mean (±SEM) pre-exercise muscle glycogen concentrations were greater after CD versus HD (171.9 ± 8.7 vs. 131.4 ± 10.3 mmol/kg wet weight, P < 0.003). Although 4 of the 6 subjects improved their time-trial performance after CD, mean performance for the time trial was not significantly different between diets (HD: 763.9 ± 35.6 s; CD: 752.9 ± 30.1 s). Thus, female cyclists can increase their muscle glycogen stores after a carbohydrate-loading diet during the follicular phase of the menstrual cycle, but we found no compelling evidence of a dietary effect on performance of a cycling time trial performed after 90 min of moderate-intensity exercise.

Restricted access

Claire Rechichi, Brian Dawson and Carmel Goodman

Some reports suggest variation in physiological responses and athletic performance, for female athletes at specific phases of the menstrual cycle. However, inconsistent findings are common due to the inappropriate verification of menstrual cycle phase, small subject numbers, high intra- and interindividual variability in estrogen and progesterone concentration, and the pulsatile secretion of these hormones. Therefore, the oral contraceptive (OC) cycle may provide a more stable environment in which to evaluate the acute effect of reproductive hormones on physiological variables and exercise performance. To date, most of the OC research has compared differences between OC use and nonuse, and few researchers have examined within-cycle effects of the OC. It is also apparent that OC use is becoming far more prevalent in athletes; hence the effect of the different exogenous and endogenous hormonal profiles on athletic performance should be investigated. Research to date identifies potential for variation in aerobic performance, anaerobic capacity, anaerobic power and reactive strength throughout an OC cycle. The purpose of this review is to present and evaluate the current literature on the physiology of exercise and athletic performance during the OC cycle.

Restricted access

Mia A. Schaumberg, Lynne M. Emmerton, David G. Jenkins, Nicola W. Burton, Xanne A.K. Janse de Jonge and Tina L. Skinner

influenced the likelihood of manipulating the menstrual cycle using an OC. 10 Less than one-fifth (17%) of respondents reported altering their scheduled bleeding pattern by deviating from package instructions, and 3.1% reported sport or athletic reasons as a reason for modifying their menstrual cycle