Cecilia Fridén

Muscle strength and endurance do not significantly vary across 3 phases of the menstrual cycle in moderately active premenopausal women.

ObjectiveTo investigate muscle strength and muscle endurance in women during 3 well-determined phases of the menstrual cycle: early follicular phase, ovulation phase, and midluteal phase. DesignProspective, within-woman analysis was performed of muscle strength and muscle endurance by repeated measures analysis of variance in 3 hormonally verified phases of 2 consecutive menstrual cycles. ParticipantsFifteen female subjects with moderate physical activity level and regular menstrual cycles volunteered to participate in the study. Analyses are based on 10 subjects who completed 2 consecutive menstrual cycles with hormonally verified phases. Main Outcome MeasurementsHandgrip strength, 1-leg hop test, isokinetic muscle strength, and muscle endurance were measured in 2 consecutive menstrual cycles in the early follicular phase, in the ovulation phase, and in the midluteal phase. Isokinetic muscle strength and endurance were tested with knee extension exercise on a standard instrument. Menstrual cycle phases were determined by analysis of sex hormone levels in serum, and ovulation was detected by luteinizing hormone surge in urine. ResultsNo significant variation in muscle strength or muscle endurance could be detected during different well-determined phases of the menstrual cycle. ConclusionsThis study detected no significant variation in muscle strength and muscle endurance during the menstrual cycle. In contrast to other studies showing variations in strength and endurance during the menstrual cycle, the present study was hormonally validated and was repeated in 2 consecutive menstrual cycles. However, it is unknown whether these data in moderately active university students would be relevant to the highly trained woman athlete.

The influence of premenstrual symptoms on postural balance and kinesthesia during the menstrual cycle

Recent studies have indicated an increased incidence of female athletic injuries during the luteal phase and the first days of the menstrual period. The purpose of this study was to investigate whether postural sway and knee-joint kinesthesia vary during the menstrual cycle, and whether premenstrual syndrome (PMS) influences postural balance and kinesthesia. A total of 13 subjects with regular menstrual cycles participated in the study. Postural sway and kinesthesia were measured in the early follicular phase, in the ovulation phase and in the mid-luteal phase. Postural sway was measured with an ankle disc placed on a Statometer, and kinesthesia was measured with a specially designed device. Menstrual cycle phases were determined by sex hormone analyses in serum and by luteinizing hormone (LH) detection in urine. The diagnosis of PMS was made prospectively using validated daily symptom ratings. Eight of 13 women were classified as having PMS. These women had a significantly greater postural sway (p = 0.002) and a greater threshold for detection of passive motion in the knee joints (p = 0.05) than women without PMS. A tendency (p = 0.06) towards greater postural sway in the mid-luteal phase was detected among women with PMS. This may explain the finding of an increased incidence of athletic injuries in the luteal phase, reported previously.

Knee joint kinaesthesia and neuromuscular coordination during three phases of the menstrual cycle in moderately active women

An increased incidence of sports related injuries in the premenstrual phase as well as in the menstrual phase of the menstrual cycle has been described. This may be explained by alterations in proprioception and neuromuscular coordination due to hormonal variations. Prospective, within women analysis of knee joint kinesthesia and neuromuscular coordination were performed by repeated measures analysis of variance in three hormonally verified phases of three consecutive menstrual cycles. Thirty-two healthy, moderately active female subjects volunteered to participate in the study. Twenty-five of the subjects performed at least one hormonally verified menstrual cycle. A specially designed device was used to investigate knee joint kinaesthesia and neuromuscular coordination was measured with the square hop test. These tests were carried out in the menstrual phase, ovulation phase and premenstrual phase determined by hormone analyses in three consecutive menstrual cycles. An impaired knee joint kinaesthesia was detected in the premenstrual phase and the performance of square hop test was significantly improved in the ovulation phase compared to the other two phases. The results of this study indicate that the variation of sex hormones in the menstrual cycle has an effect on performance of knee joint kinaesthesia and neuromuscular coordination.

Altered postural control during the luteal phase in women with premenstrual symptoms.

The purpose of this study was to investigate postural control in women with and without premenstrual symptoms (PMS) in three hormonally verified phases of the menstrual cycle. Thirty-two women were recruited to participate in the study and 25 of these women were included in the results. Menstrual cycle phases were determined by sex hormone analyses in serum and LH detection in urine. A prospective rating of PMS was used to divide the subjects into two groups: one with PMS (cyclic) and one without (non-cyclic). For measurement of postural control, subjects stood on a force platform (AMTI®) in two-legged stance (eyes open and closed) and one-legged stance (eyes open and closed). There were no significant differences in the two-legged stance between the phases of the menstrual cycle or between groups. In one-legged stance with eyes open, there was a significant increase in postural displacement in the mid-luteal phase in the cyclic group, but no differences were detected between phases in the non-cyclic group. These findings may be related to the previously reported increased injury rate and psychomotor slowing in the luteal phase in women with PMS.

Long-term health-enhancing physical activity in rheumatoid arthritis - the PARA 2010 study

BackgroundPeople with rheumatoid arthritis (RA) suffer increased risk of disability andpremature mortality. Health-enhancing physical activity (HEPA) could be one importantfactor to reduce this risk. Rising health care costs call for the development and evaluation ofnew modes of rehabilitation, including physical activity in settings outside the health caresystem.Methods/DesignThis cohort study targets 450 patients with RA that do not currently meet HEPA recommendations, recruited from six hospitals reporting to the Swedish Rheumatology Quality Registers (SRQ). We have developed a two-year real-life intervention program including a minimum of twice-weekly circuit training, moderately intense physical activity the remaining days of the week and group meetings to support behavior change every other week. Our hypothesis is that increased physical activity and exercise will improve perceived health, reduce pain and fatigue, increase muscle function and aerobic capacity, impact psychosocial factors and prevent future cardiovascular events. Research questions regard outcomes, retention rates, dose–response matters and the exploration of responder characteristics. This protocol outlines recruitment procedure, design, assessment methods and the intervention program of the study.DiscussionThe PARA 2010 project is designed to expand the knowledge on HEPA in RA by a progressive approach regarding population, setting, intervention, time frames and outcome measures. To our knowledge this is the first long-term HEPA program based on Social Cognitive Theory, and performed in a real life environment to demonstrate if this new setting can promote increased and maintained physical activity in people with RA.Trial registration numberISRCTN25539102

Nitrosative modifications of the Ca2+ release complex and actin underlie arthritis-induced muscle weakness.

Objective Skeletal muscle weakness is a prominent clinical feature in patients with rheumatoid arthritis (RA), but the underlying mechanism(s) is unknown. Here we investigate the mechanisms behind arthritis-induced skeletal muscle weakness with special focus on the role of nitrosative stress on intracellular Ca2+ handling and specific force production. Methods Nitric oxide synthase (NOS) expression, degree of nitrosative stress and composition of the major intracellular Ca2+ release channel (ryanodine receptor 1, RyR1) complex were measured in muscle. Changes in cytosolic free Ca2+ concentration ([Ca2+]i) and force production were assessed in single-muscle fibres and isolated myofibrils using atomic force cantilevers. Results The total neuronal NOS (nNOS) levels were increased in muscles both from collagen-induced arthritis (CIA) mice and patients with RA. The nNOS associated with RyR1 was increased and accompanied by increased [Ca2+]i during contractions of muscles from CIA mice. A marker of peroxynitrite-derived nitrosative stress (3-nitrotyrosine, 3-NT) was increased on the RyR1 complex and on actin of muscles from CIA mice. Despite increased [Ca2+]i, individual CIA muscle fibres were weaker than in healthy controls, that is, force per cross-sectional area was decreased. Furthermore, force and kinetics were impaired in CIA myofibrils, hence actin and myosin showed decreased ability to interact, which could be a result of increased 3-NT content on actin. Conclusions Arthritis-induced muscle weakness is linked to nitrosative modifications of the RyR1 protein complex and actin, which are driven by increased nNOS associated with RyR1 and progressively increasing Ca2+ activation.

Is home-based pelvic floor muscle training effective in treatment of urinary incontinence after birth in primiparous women? A randomized controlled trial

To assess the effect of pelvic floor muscle training (PFMT) on pelvic floor muscle strength and urinary incontinence (UI) in primiparous women who underwent a home training program between three and 9 months after delivery.

Too little sleep and an unhealthy diet could increase the risk of sustaining a new injury in adolescent elite athletes

Little is known about health variables and if these variables could increase the risk of injuries among adolescent elite athletes. The primary aim was to present overall data on self‐perceived stress, nutrition intake, self‐esteem, and sleep, as well as gender and age differences, on two occasions among adolescent elite athletes. A secondary aim was to study these health variables as potential risk factors on injury incidence. A questionnaire was e‐mailed to 340 adolescent elite athletes on two occasions during a single school year: autumn semester and spring semester. The results show that during autumn semester, the recommended intake of fruits, vegetables, and fish was not met for 20%, 39%, and 43% of the adolescent elite athletes, respectively. The recommended amount of sleep during weekdays was not obtained by 19%. Multiple logistic regression showed that athletes sleeping more than 8 h of sleep during weekdays reduced the odds of injury with 61% (OR, 0.39; 95% CI, 0.16–0.99) and athletes reaching the recommended nutrition intake reduced the odds with 64% (OR, 0.36; 95% CI, 0.14–0.91). Our findings suggest that nutrition intake and sleep volume are of importance in understanding injury incidence.

An outsourced health-enhancing physical activity programme for people with rheumatoid arthritis: exploration of adherence and response

Objectives. The aims of this study were to document adherence to and changes in health-enhancing physical activity (HEPA) levels and self-reported and assessed functioning and to explore aspects of adherence and response during the first year of an outsourced 2-year HEPA programme in people with RA. Methods. Two-hundred and twenty patients participated in this observational cohort study, which included daily physical activity, twice-weekly circuit training and biweekly support group meetings. Self-reported data included current (past week) and maintained (past 6 months) HEPA levels, sociodemographics and disease-related and psychosocial factors. Tests of aerobic capacity and muscle function were performed and anthropometric data were collected. Results. Eighty-eight per cent of the participants completed 1 year assessments. Self-reported current and maintained HEPA increased. General health perception and a number of other self-reported disease-related and psychosocial factors improved, while exercise self-efficacy declined. Aerobic capacity, timed standing and grip strength improved and waist circumference decreased. The mean number of circuit training sessions performed was 48, the mean number of days with HEPA was 189 and the mean number of support group meetings attended was 9. Better adherence to circuit training improved general health, and better adherence to group meetings improved timed standing. Exercise self-efficacy improved among those adhering more to circuit training or support group meetings. Conclusion. The outsourced HEPA programme had high retention and reasonable adherence. A number of health outcomes improved. Relationships between adherence to the programme components and response were not clear-cut and need further attention. Trial registration: ISRCTN register; http://www.controlled-trials.com. Trial registration number ISRCTN25539102.

Who Makes It to the Base? Selection Procedure for a Physical Activity Trial Targeting People With Rheumatoid Arthritis

To compare those who were finally included in a large well‐defined sample of individuals with rheumatoid arthritis (RA) at target for a physical activity (PA) trial with those who were not.