ABSTRACTRomero-Parra, N, Cupeiro, R, Alfaro-Magallanes, VM, Rael, B, Rubio-Arias, JA, Peinado, AB, and Benito, PJ, IronFEMME Study Group. Exercise-induced muscle damage during the menstrual cycleA ...systematic review and meta-analysis. J Strength Cond Res XX(X)000–000, 2020—A strenuous bout of exercise could trigger damage of muscle tissue, and it is not clear how sex hormone fluctuations occurring during the menstrual cycle (MC) affect this response. The aims of this study were to systematically search and assess studies that have evaluated exercise-induced muscle damage (EIMD) in eumenorrheic women over the MC and to perform a meta-analysis to quantify which MC phases display the muscle damage response. The guidelines of the Preferred Reported Items for Systematic Reviews and Meta-Analysis were followed. A total of 19 articles were analyzed in the quantitative synthesis. Included studies examined EIMD in at least one phase of the following MC phasesearly follicular phase (EFP), late follicular phase (LFP), or midluteal phase (MLP). The meta-analysis demonstrated differences between MC phases for delayed onset muscle soreness (DOMS) and strength loss (p < 0.05), whereas no differences were observed between MC phases for creatine kinase. The maximum mean differences between pre-excercise and post-exercise for DOMS were EFP6.57 (4.42, 8.71), LFP5.37 (2.10, 8.63), and MLP3.08 (2.22, 3.95), whereas for strength loss were EFP−3.46 (−4.95, −1.98), LFP−1.63 (−2.36, −0.89), and MLP−0.72 (−1.07, −0.36) (p < 0.001). In conclusion, this meta-analysis suggests that hormone fluctuations throughout the MC affect EIMD in terms of DOMS and strength loss. Lower training loads or longer recovery periods could be considered in the EFP, when sex hormone concentrations are lower and women may be more vulnerable to muscle damage, whereas strength conditioning loads could be enhanced in the MLP.
Reference values are necessary for classifying children, for health screening, and for early prevention as many non-communicable diseases aggravate during growth and development. While physical ...fitness reference standards are available in children aged 6 and older, such information is lacking in preschool children. Therefore, the purposes of this study were (1) to provide sex-and age-specific physical fitness reference standards for Spanish preschool children; and (2) to study sex differences across this age period and to characterise fitness performance throughout the preschool period.
Cross-sectional.
A total of 3179 preschool children (1678 boys) aged 2.8–6.4 years old from Spain were included in the present study. Physical fitness was measured using the PREFIT battery.
Age- and sex-specific percentiles for the physical fitness components are provided. Boys performed better than girls in the cardiorespiratory fitness, muscular strength, and speed-agility tests over the whole preschool period studied and for the different percentiles. In contrast, girls performed slightly better than boys in the balance test. Older children had better performance in all fitness tests than their younger counterparts.
Our study provides age- and sex-specific physical fitness reference standards in preschool children allowing interpretation of fitness assessment. Sexual dimorphism in fitness tests exists already at preschool age, and these differences become larger with age. These findings will help health, sport, and school professionals to identify preschool children with a high/very low fitness level, to examine changes in fitness over time, and to analyse those changes obtained due to intervention effects.
Rheumatoid arthritis (RA) is an autoimmune disease that causes inflammation, pain, and ultimately, bone erosion of the joints. The causes of this disease are multifactorial, including genetic ...factors, such as the presence of the human leukocyte antigen (HLA)-DRB1*04 variant, alterations in the microbiota, or immune factors including increased cytotoxic T lymphocytes (CTLs), neutrophils, or elevated M1 macrophages which, taken together, produce high levels of pro-inflammatory cytokines. In this review, we focused on the function exerted by osteoclasts on osteoblasts and other osteoclasts by means of the release of exosomal microRNAs (miRNAs). Based on a thorough revision, we classified these molecules into three categories according to their function: osteoclast inhibitors (miR-23a, miR-29b, and miR-214), osteoblast inhibitors (miR-22-3p, miR-26a, miR-27a, miR-29a, miR-125b, and miR-146a), and osteoblast enhancers (miR-20a, miR-34a, miR-96, miR-106a, miR-142, miR-199a, miR-324, and miR-486b). Finally, we analyzed potential therapeutic targets of these exosomal miRNAs, such as the use of antagomiRs, blockmiRs, agomiRs and competitive endogenous RNAs (ceRNAs), which are already being tested in murine and ex vivo models of RA. These strategies might have an important role in reestablishing the regulation of osteoclast and osteoblast differentiation making progress in the development of personalized medicine.
Rheumatoid factor (RF) and anti-citrullinated protein antibodies (ACPAs) are the most frequently used rheumatoid arthritis (RA) diagnostic markers, but they are unable to anticipate the patient's ...evolution or response to treatment. The aim of this study was to identify possible severity biomarkers to predict an upcoming flare-up or remission period. To address this objective, sera and anticoagulated blood samples were collected from healthy controls (HCs; n = 39) and from early RA (n = 10), flare-up (n = 5), and remission (n = 16) patients. We analyzed leukocyte phenotype markers, regulatory T cells, cell proliferation, and cytokine profiles. Flare-up patients showed increased percentages of cluster of differentiation (CD)3
CD4
lymphocytes (
< 0.01) and granulocytes (
< 0.05) but a decreased natural killer (NK)/T lymphocyte ratio (
< 0.05). Analysis of leukocyte markers by principal component analysis (PCA) and receiver operating characteristic (ROC) curves showed that CD45RO
(
< 0.0001) and CD45RA
(
< 0.0001) B lymphocyte expression can discriminate between HCs and early RA patients, while CD3
CD4
lymphocyte percentage (
< 0.0424) and CD45RA
(
< 0.0424), CD62L
(
< 0.0284), and CD11a
(
< 0.0185) B lymphocyte expression can differentiate between flare-up and RA remission subjects. Thus, the combined study of these leukocyte surface markers could have potential as disease severity biomarkers for RA, whose fluctuations could be related to the development of the characteristic pro-inflammatory environment.
Abstract To explore how sex hormone fluctuations may affect bone metabolism, this study aimed to examine P1NP and β-CTX-1 concentrations across the menstrual and oral contraceptive (OC) cycle phases ...in response to running. 17β-oestradiol, progesterone, P1NP and β-CTX-1 were analysed pre- and post-exercise in eight eumenorrheic females in the early-follicular, late-follicular, and mid-luteal phases, while 8 OC users were evaluated during the withdrawal and active pill-taking phases. The running protocol consisted of 8 × 3min treadmill runs at 85% of maximal aerobic speed. 17β-oestradiol concentrations (pg·ml −1 ) were lower in early-follicular (47.22 ± 39.75) compared to late-follicular (304.95 ± 235.85; p = < 0.001) and mid-luteal phase (165.56 ± 80.6; p = 0.003) and higher in withdrawal (46.51 ± 44.09) compared to active pill-taking phase (10.88 ± 11.24; p < 0.001). Progesterone (ng·ml −1 ) was higher in mid-luteal (13.214 ± 4.926) compared to early-follicular (0.521 ± 0.365; p < 0.001) and late-follicular phase (1.677 ± 2.586; p < 0.001). In eumenorrheic females, P1NP concentrations (ng·ml −1 ) were higher in late-follicular (69.97 ± 17.84) compared to early-follicular (60.96 ± 16.64; p = 0.006;) and mid-luteal phase (59.122 ± 11.77; p = 0.002). β-CTX-1 concentrations (ng·ml −1 ) were lower in mid-luteal (0.376 ± 0.098) compared to late-follicular (0.496 ± 0.166; p = 0.001) and early-follicular phase (0.452 ± 0.148; p = 0.039). OC users showed higher post-exercise P1NP concentrations in withdrawal phase (61.75 ± 8.32) compared to post-exercise in active pill-taking phase (45.45 ± 6; p < 0.001). Comparing hormonal profiles, post-exercise P1NP concentrations were higher in early-follicular (66.91 ± 16.26; p < 0.001), late-follicular (80.66 ± 16.35; p < 0.001) and mid-luteal phases (64.57 ± 9.68; p = 0.002) to active pill-taking phase. These findings underscore the importance of studying exercising females with different ovarian hormone profiles, as changes in sex hormone concentrations affect bone metabolism in response to running, showing a higher post-exercise P1NP concentrations in all menstrual cycle phases compared with active pill-taking phase of the OC cycle.
The present study describes the oxygen uptake and total energy expenditure (including both aerobic and anaerobic contribution) response during three different circuit weight training (CWT) protocols ...of equivalent duration composed of free weight exercises, machine exercises, and a combination of free weight exercises intercalating aerobic exercise.
Controlled, randomized crossover designs.
Subjects completed in a randomized order three circuit weight training protocols of the same duration (3 sets of 8 exercises, 45min 15s) and intensity (70% of 15 repetitions maximum). The circuit protocols were composed of free weight exercises, machine exercises, or a combination of free weight exercises with aerobic exercise. Oxygen consumption and lactate concentration were measured throughout the circuit to estimate aerobic and anaerobic energy expenditure respectively.
Energy expenditure is higher in the combined exercise protocol (29.9±3.6 ml/kg/min), compared with Freeweight (24.2±2.8ml/kg/min) and Machine (20.4±2.9ml/kg/min). The combined exercise protocol produced the highest total energy expenditure but the lowest lactate concentration and perceived exertion. The anaerobic contribution to total energy expenditure was higher in the machine and free weight protocols compared with the combined exercise protocol (6.2%, 4.6% and 2.3% respectively).
In the proposed protocols, the combined exercise protocol results in the highest oxygen consumption. Total energy expenditure is related to the type of exercise included in the circuit. Anaerobic contributions to total energy expenditure during circuit weight training may be modest, but lack of their estimation may underestimate total energy expenditure.
ClinicalTrials.gov NCT01116856.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The aim of the present study was to investigate the existence of a relative age effect (RAE) on physical fitness of preschoolers. Anthropometry and physical fitness were assessed in 3147 children ...(3-5 years old) using the PREFIT battery. Based on the birth year, participants were divided into 3year groups (3-, 4- and 5-years). Within each year group, 4quarter groups were created: quarter 1, preschoolers born from January to March; quarter 2, from April to June; quarter 3, from July to September; quarter 4, from October to December. The MANCOVA analysis revealed a main effect of year group (Wilks' λ = 0.383; F
10,5996
= 369.64; p < 0.001, η
p
2
= 0.381) and of quarter (Wilks' λ = 0.874; F
15,8276.6
= 27.67; p < 0.001; η
p
2
= 0.044) over the whole battery of tests. To the best of our knowledge, this is the first study to report the existence of RAE at the preschool stage. In general, performance improved as the relative age increased (i.e., those born in quarter 1 performed better than those in the other quarters). Individualization strategies should be addressed within the same academic year not only in elementary or secondary years but also in preschoolers.
The aim of this study was to examine whether a type of exercise favors better compliance with a prescribed diet, higher eating-related motivation, healthier diet composition or greater changes in ...body composition in overweight and obese subjects. One hundred and sixty-two (males
= 79), aged 18-50 years, were randomized into four intervention groups during 24 weeks: strength, endurance, combined strength + endurance and guideline-based physical activity; all in combination with a 25-30% caloric restriction diet. A food frequency questionnaire and a "3-day food and drink record" were applied pre- and post-intervention. Diet and exercise-related motivation levels were evaluated with a questionnaire developed for this study. Body composition was assessed by DXA and habitual physical activity was measured by accelerometry. Body weight, body mass index (BMI) and body fat percentage decreased and lean body mass increased after the intervention, without differences by groups. No interactions were observed between intervention groups and time; all showing a decreased in energy intake (
< 0.001). Carbohydrate and protein intakes increased, and fat intake decreased from pre- to post-intervention without significant interactions with intervention groups, BMI category or gender (
< 0.001). Diet-related motivation showed a tendency to increase from pre- to post-intervention (70.0 ± 0.5 vs 71.0 ± 0.6,
= 0.053), without significant interactions with intervention groups, BMI or gender. Regarding motivation for exercise, gender x time interactions were observed (
= 7.452,
= 0.007): Women increased their motivation after the intervention (pre: 17.6 ± 0.3, post: 18.2 ± 0.3), while men maintained it. These findings suggest that there are no substantial effects of exercise type on energy intake, macronutrient selection or body composition changes. After a six-month weight loss program, individuals did not reduce their motivation related to diet or exercise, especially women. Individuals who initiate a long-term exercise program do not increase their energy intake in a compensatory fashion, if diet advices are included.
The aim of this study was to evaluate whether the menstrual cycle and its underlying hormonal fluctuations affect muscle damage and inflammation in well-trained females following an eccentric ...exercise. Nineteen eumenorrheic women performed an eccentric squat-based exercise in the early follicular phase, late follicular phase and mid-luteal phase of their menstrual cycle. Sex hormones and blood markers of muscle damage and inflammation -creatine kinase, myoglobin, lactate dehydrogenase, interleukin-6, tumoral necrosis factor-, and C reactive protein- were analyzed in each phase. No effect of menstrual cycle phase was observed (
> 0.05), while an interaction for interleukin-6 was shown (
= 0.047). Accordingly, a moderate effect size 0.68 (0.53)-0.84 (0.74), indicated that interleukin-6 values 2 h post-trial (2.07 1.26 pg/mL) were likely to be higher than baseline (1.59 0.33 pg/mL), 24 h (1.50 0.01 pg/mL) and 48 h (1.54 0.13 pg/mL) in the mid-luteal phase. Blood markers of muscle damage and inflammation were not affected by the menstrual cycle in well-trained women. The eccentric exercise barely triggered muscle damage and hence, no inflammation was observed, possibly due to participants training status. The mid-luteal phase was the only phase reflecting a possible inflammatory response in terms of interleukin-6, although further factors than sex hormones seem to be responsible for this finding.
ABSTRACTBarba-Moreno, L, Cupeiro, R, Romero-Parra, N, Janse de Jonge, XA, and Peinado, AB. Cardiorespiratory Responses to Endurance Exercise Over the Menstrual Cycle and With Oral Contraceptive Use. ...J Strength Cond Res XX(X)000–000, 2019—Female steroid hormone fluctuations during the menstrual cycle and exogenous hormones from oral contraceptives may have potential effects on exercise performance. The aim of this study was to investigate the effects of these fluctuations on cardiorespiratory responses during steady-state exercise in women. Twenty-three healthy endurance-trained women performed 40 minutes of running at 75% of their maximal aerobic speed during different phases of the menstrual cycle (n = 15; early follicular phase, midfollicular phase, and luteal phase) or oral contraceptive cycle (n = 8; hormonal phase and nonhormonal phase). Ventilatory parameters and heart rate (HR) were measured. Data were analyzed using a mixed linear model. For the eumenorrheic group, significantly higher oxygen uptake (p = 0.049) and percentage of maximum oxygen uptake (p = 0.035) were observed during the midfollicular phase compared with the early follicular. Heart rate (p = 0.004), oxygen ventilatory equivalent (p = 0.042), carbon dioxide ventilatory equivalent (p = 0.017), and tidal volume (p = 0.024) increased during luteal phase in comparison with midfollicular. In oral contraceptive users, ventilation (p = 0.030), breathing frequency (p = 0.018), oxygen ventilatory equivalent (p = 0.032), and carbon dioxide ventilatory equivalent (p = 0.001) increased during the hormonal phase. No significant differences were found for the rest of the parameters or phases. Both the eumenorrheic group and oral contraceptive group showed a significant increase in some ventilatory parameters during luteal and hormonal phases, respectively, suggesting lower cardiorespiratory efficiency. However, the lack of clinical meaningfulness of these differences and the nondifferences of other physiological variables, indicate that the menstrual cycle had a small impact on submaximal exercise in the current study.
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