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Background: Strength training (ST) primarily enhances physical fitness (e.g., muscle strength, power, speed) and bone density in female soccer players. Less information is available on the injury preventive effects of ST in female athletes. Accordingly, this study aimed to investigate the effects of a 12-week in-season ST on measures of physical fitness and injury occurrence in young elite female soccer players. Methods: Thirty elite female soccer players (15.4 ± 1.9 years; maturity offset + 2.3 ± 1.1 years) participated in this study, and were randomly assigned to a strength training group (STG, n = 14) or an active control (CG, n = 16) group. ST lasted twelve weeks and included full body muscle strengthening exercises using primarily weight machines at progressive intensities ranging between 40 and 85% of the one-repetition-maximum (1-RM). The CG practiced a traditional soccer training program. Overall, training volumes of the two groups were similar with a training load (rating of perceived exertion × time) of 1158.4 ± 67.7 arbitrary unity (AU) for the STG and 1188.8 ± 44.1 AU for the CG. Pre and post training, the following physical fitness tests were applied: dynamic muscle strength (relative [to body mass] and absolute 1-RM bench/leg press, lat-pull down), jump performance (countermovement jump [CMJ], squat jump [SJ], five-jump-test [5JT]), linear-sprint speed (5-m, 10-m, 30-m), change-of-direction speed (T-test with and without ball), sport-specific performance (Yo-Yo Intermittent Level1 [YYIRTL1], and repeated shuttle sprint ability [RSSA]). The injury rate per 1000-h exposure was monitored throughout the soccer season. Results: No significant baseline differences were observed between groups. Statistically significant group-by-time interactions were found for absolute (p < 0.001, d = 2.59) and relative 1-RM bench press (p < 0.001, d = 2.39), absolute 1-RM lat-pull down (p < 0.001, d = 1.68), and relative 1-RM leg press (p < 0.001, d = 1.72). Significant group-by-time interactions were observed for CMJ (p = 0.005, d = 1.27), RSSAmean (p = 0.007, d = 0.81), and RSSAtotal (p < 0.001, d = 1.90). Post-hoc tests indicated that the STG group demonstrated greater improvements in all tested variables compared to CG (1.2 < d < 2.5). However, no significant interaction effects were noted for measures of linear sprint speed and YYIRTL1 performance. Additionally, non-contact injuries during the season were significantly lower (p = 0.003, d = 1.31) in the STG (0.48/1000 h of exposure) than the CG (2.62/1000 h of exposure). Conclusions: Twelve weeks of an in-season ST resulted in larger physical fitness improvements and fewer injuries compared with an active control in elite young female soccer players. Accordingly, ST should be systematically applied in female soccer to enhance performance and prevent injuries. Key Finding: This study showed that the incorporation of 12 weeks of strength training with two weekly sessions during the soccer season improves anthropometric and body composition characteristics as well as measures of physical fitness in adolescent elite female soccer players. Strength training reduces the incidence of non-contact injuries in young female soccer players. The usage of strength training machines is safe in elite young female soccer players with no previous experience in weightlifting. [ABSTRACT FROM AUTHOR]

Background: Well programmed strength and conditioning training is an indispensable part of the long-term training process for athletes in individual and team sports to improve performance and prevent injuries. Yet, there is a limited number of studies available that examine the effects of resistance training (RT) on muscular fitness and physiological adaptations in elite female athletes. Objectives: This systematic review aimed to summarize recent evidence on the long-term effects of RT or combinations of RT with other strength-dominated exercise types on muscular fitness, muscle morphology, and body composition in female elite athletes. Materials and Methods: A systematic literature search was conducted in nine electronic databases (Academic Search Elite, CINAHL, ERIC, Open Access Theses and Dissertations, Open Dissertations, PsycINFO, PubMed/MEDLINE, Scopus, and SPORTDiscus) from inception until March 2022. Key search terms from the MeSH database such as RT and strength training were included and combined using the operators "AND," "OR," and "NOT". The search syntax initially identified 181 records. After screening for titles, abstracts, and full texts, 33 studies remained that examined the long-term effects of RT or combinations of RT with other strength-dominated exercise types on muscular fitness, muscle morphology, and body composition in female elite athletes. Results: Twenty-four studies used single-mode RT or plyometric training and nine studies investigated the effects of combined training programs such as resistance with plyometric or agility training, resistance and speed training, and resistance and power training. The training duration lasted at least 4 weeks, but most studies used ~ 12 weeks. Studies were generally classified as 'high-quality' with a mean PEDro score of 6.8 (median 7). Irrespective of the type or combination of RT with other strength-dominated exercise regimens (type of exercise, exercise duration, or intensity), 24 out of 33 studies reported increases in muscle power (e.g., maximal and mean power; effect size [ES]: 0.23 < Cohen's d < 1.83, small to large), strength (e.g., one-repetition-maximum [1RM]; ES: 0.15 < d < 6.80, small to very large), speed (e.g., sprint times; ES: 0.01 < d < 1.26, small to large), and jump performance (e.g., countermovement/squat jump; ES: 0.02 < d < 1.04, small to large). The nine studies that examined the effects of combined training showed significant increases on maximal strength (ES: 0.08 < d < 2.41, small to very large), muscle power (ES: 0.08 < d < 2.41, small to very large), jump and sprint performance (ES: 0.08 < d < 2.41, small to very large). Four out of six studies observed no changes in body mass or percentage of body fat after resistance or plyometric training or combined training (ES: 0.026 < d < 0.492, small to medium). Five out of six studies observed significant changes in muscle morphology (e.g., muscle thickness, muscle fiber cross-sectional area; ES: 0.23 < d < 3.21, small to very large). However, one study did not find any changes in muscle morphology (i.e., muscle thickness, pennation angle; ES: 0.1 < d < 0.19, small). Conclusion: Findings from this systematic review suggest that RT or combined RT with other strength-dominated exercise types leads to significant increases in measures of muscle power, strength, speed, and jump performance in elite female athletes. However, the optimal dosage of programming parameters such as training intensity and duration necessary to induce large effects in measures of muscular fitness and their physiological adaptations remain to be resolved in female elite athletes. [ABSTRACT FROM AUTHOR]

The aim of this systematic review was to summarize the evidence on the acute and long-term effects of exercise training on PV, in both trained and untrained individuals and to examine associations between changes in %PVV and change in physical/physiological performance. Despite the status of participants and the exercise duration or intensity, all the acute studies reported a significant decrease of PV (effect size: 0.85

The cortisol awakening response (CAR) is commonly used as a marker of psychological stress; however, it is unknown whether CAR is affected by regular physical-exercise-induced stress. Purpose: To assess the relationship between training load and CAR. Methods: Recreational endurance athletes were recruited from local running clubs. Subjects (n = 15) completed training logs for 2 wk, with various training loads, including psychometric analysis (Recovery-Stress Questionnaire for Athletes). Subjects provided saliva samples each day immediately after waking and 30 min postwaking. Samples were analyzed for cortisol concentration via enzyme-linked immunosorbent assay and subsequently were analyzed for CAR and CAR%. Daily training load was calculated and analyzed as training impulse. Simple linear regression was used to assess the relationship between CAR and training impulse. Results: CAR (r2 =.352, P =.025) and CAR% (r2 =.373, P =.012) both showed a significant negative relationship with training load. Conclusions: These results suggest that CAR is affected by regular exercise training loads in recreational athletes. It is recommended that future CAR research control for fitness level and exercise training load in physically active populations. [ABSTRACT FROM AUTHOR]

Background: Ageing is accompanied by decreases in physical capacity and physiological regulatory mechanisms including altered hormonal regulation compared with age-matched sedentary people. The potential benefits of exercise in restoring such altered hormone production and secretion compared to age-matched physically inactive individuals who are ageing remains unclear. Objectives: The aim of this systematic review was to summarise the findings of exercise training in modulating levels of ostensibly anabolic and catabolic hormones in adults aged > 40 years. Methods: We searched the following electronic databases (to July 2021) without a period limit: Cochrane Library, PubMed, Science Direct, Scopus, SPORTDiscus and Web of Science. Additionally, a manual search for published studies in Google Scholar was conducted for analysis of the 'grey literature' (information produced outside of traditional commercial or academic publishing and distribution channels). The initial search used the terms 'ageing' OR 'advanced age' OR 'old people' OR 'older' OR elderly' AND 'anabolic hormones' OR 'catabolic hormones' OR 'steroid hormones' OR 'sex hormones' OR 'testosterone' OR 'cortisol' OR 'insulin' OR 'insulin-like growth factor-1' OR 'IGF-1' OR 'sex hormone-binding globulin' OR 'SHBG' OR 'growth hormone' OR 'hGH' OR 'dehydroepiandrosterone' OR 'DHEA' OR 'dehydroepiandrosterone sulfate (DHEA-S)' AND 'exercise training' OR 'endurance training' OR 'resistance training' OR ' strength training' OR 'weight-lifting' OR 'high-intensity interval training' OR 'high-intensity interval exercise' OR 'high-intensity intermittent training' OR 'high-intensity intermittent exercise' OR 'interval aerobic training' OR 'interval aerobic exercise' OR 'intermittent aerobic training' OR 'intermittent aerobic exercise' OR 'high-intensity training' OR 'high-intensity exercise' OR 'sprint interval training' OR 'sprint interval exercise' OR 'combined exercise training' OR 'anaerobic training'. Only eligible full texts in English or French were considered for analysis. Results: Our search identified 484 records, which led to 33 studies for inclusion in the analysis. Different exercise training programs were used with nine studies using endurance training programs, ten studies examining the effects of high-intensity interval training, and 14 studies investigating the effects of resistance training. Most training programs lasted ≥ 2 weeks. Studies, regardless of the design, duration or intensity of exercise training, reported increases in testosterone, sex hormone-binding globulin (SHBG), insulin-like growth factor-1 (IGF-1), human growth hormone (hGH) or dehydroepiandrosterone (DHEA) (effect size: 0.19 < d < 3.37, small to very large) in both older males and females. However, there was no consensus on the effects of exercise on changes in cortisol and insulin in older adults. Conclusion: In conclusion, findings from this systematic review suggest that exercise training increases basal levels of testosterone, IGF-1, SHBG, hGH and DHEA in both male and females over 40 years of age. The increases in blood levels of these hormones were independent of the mode, duration and intensity of the training programs. However, the effects of long-term exercise training on cortisol and insulin levels in elderly people are less clear. [ABSTRACT FROM AUTHOR]

The objective of present study is to investigate the effects of walk training with and without blood flow restriction (BFR and no-BFR) on lipid profiles, inflammatory and haematological factors in over-weighed men. Participants were divided into BFR (n = 9) or no-BFR (n = 9) groups. Both groups were exposed to 8-week walk training on a treadmill: 3 sessions/week at a speed of 50 m/min, 5 sets × 2 min/session. There were differences in pre- to post-levels of (TG) and fibrinogen in the BFR group (p ≤ 0.05) that were accompanied by changes in red blood cells (RBC), haemoglobin (HGB) and haematocrit (HCT) levels (p ≤ 0.05). RBC levels were increased in the BFR group (p ≤ 0.05). The groups differed in their mean corpuscular volume (MCV) and mean corpuscular haemoglobin concentration (MCHC). These findings suggest the efficiency of BFR walk training in individuals exposed to chronic diseases associated with overweight, such as metabolic syndrome. [ABSTRACT FROM AUTHOR]

This study investigated the effect of oral contraceptive (OC) use on acute changes in steroid hormone concentrations and tryptophan (TRP) metabolites in response to strength exercise. Twenty-one women (age: 23 ± 3 years), 8 combined OC users (OC group) and 13 naturally cycling women (menstrual cycle [MC] group), participated. Testing was performed during the pill-free interval for the OC group and the follicular phase for the MC group. Subjects completed an intense strength exercise protocol (4 x 10 repetitions back squat). Blood samples were taken at baseline (T0), post-exercise (T1), and after 24 hours (T2) to determine serum concentrations of cortisol, estradiol, testosterone, TRP, and kynurenine (KYN). Statistical significance was defined asp <0.05. At T0, the OC group showed higher cortisol (OC: 493.7 ± 47.1 ng⋅ml-1, MC: 299.1 ± 62.7 ng⋅ml-1, p < 0.001) and blood lactate(OC: 1.81 ±0.61 mmol⋅L-1, MC: 1.06 ± 0.30 mmol⋅L-1, p = 0.001) and lower estradiol (OC: 31.12 ± 4.24 pg⋅mL-1, MC: 38.34 ± 7.50 pg⋅mL-1, p = 0.023) and KYN (OC: 1.15 ± 0.23 μmol⋅L-1, MC: 1.75 ± 0.50 μmol⋅L-1, p = 0.005). No significant interactions (group x time, p> 0.05) were found for the hormones and TRP metabolites assessed. Oral contraceptive use did not affect the physiological response of steroid hormones and TRP metabolites to acute strength exercise during the low hormone phase of the contraceptive or MC in healthy young women, even when some baseline concentrations differed between groups. Consequently, these findings provide important implications for practitioners testing heterogeneous groups of female athletes. [ABSTRACT FROM AUTHOR]

Maximum strength training induces various improvements in the rate of force development (RFD) on a group level, but no study has investigated inter-individual adaptations in RFD. Fourteen men (28 ± 6 years old) performed the same 10-week maximum strength and then a 10-week power training program. Maximal force and RFD were recorded during maximal isometric leg extension voluntary contractions repeatedly before every 7th training session (2 sessions/week). After the intervention, subjects were retrospectively divided into three groups based on their RFD improvements: (1) improved only during the maximum strength period (MS-responders, + 100 ± 35%), (2) improved only during the power period (P-responders, + 53 ± 27%) or (3) no improvement at all (non-responders, + 3 ± 9%). All groups increased dynamic 1RM equally, but baseline 1RM was greater (p < 0.05) in responder vs non-responder groups. MS-responders had higher electrical stimulation-induced torque at baseline and they improved (+ 35 ± 28%) power production at 50% 1RM load more than P- (- 7 ± 20%, p = 0.052) and non-responders (+ 3 ± 6%, p = 0.066) during the maximum strength training period. MS-responders increased vastus lateralis cross-sectional area (+ 12 ± 9%, p < 0.01) as did P-responders (+ 10 ± 7%, p = 0.07), whereas non-responders were unchanged. Free androgen index (FAI) in responders was higher (+ 34%, p < 0.05) compared to non-responders at baseline. The maximum strength period decreased testosterone (- 17 ± 12; 17 ± 22%), FAI ratio (- 12 ± 14; - 21 ± 23%) and testosterone/cortisol ratio (- 17 ± 25; - 31 ± 20%) in MS and P-responders, respectively. During the P-period hormonal levels plateaued. To conclude, periodized strength training induced different inter-individual physiological responses, and thus RFD development may vary between individuals. Therefore, RFD seems to be a useful tool for planning and monitoring strength training programs for individual neuromuscular performance needs. [ABSTRACT FROM AUTHOR]

Objective: This study was undertaken to examine substrate utilization and hormonal responses to moderate intensity exercise in the same group of women across gestation.Study Design: Glucose, triglyceride, insulin, glucagon, cortisol, growth hormone, and blood urea nitrogen levels were measured in 12 women at rest and after exercise. Heart rate, oxygen uptake, and respiratory exchange ratio were measured at rest and during exercise. Urine urea nitrogen levels, urine volume, and creatinine levels were measured 24 hours before and after exercise. Each woman completed a 30-minute treadmill walk at 65% of her predicted maximal heart rate at the same time of day during the 22nd and 33rd weeks of gestation and at 14 weeks after delivery.Results: There were no significant differences between exercise trials in oxygen uptake, respiratory exchange ratio, or heart rate. Pregnancy elevated resting triglyceride levels but lowered plasma glucose levels. Exercise during pregnancy caused a reduction in plasma glucose levels but elevated circulating triglyceride levels (P <.05). Resting levels of cortisol, growth hormone, and insulin were elevated during pregnancy compared with after delivery, but resting glucagon levels were not affected by pregnancy. Exercise caused circulating levels of cortisol, growth hormone, and glucagon to increase (P <.05). The exercise-induced change in the cortisol level was greater during pregnancy than that after delivery. The exercise-induced changes in growth hormone and glucagon levels were greatest after delivery compared with those during pregnancy (P <.05). Exercise reduced insulin levels (P <.05), with the greatest reduction at 33 weeks' gestation. There were no significant differences in urine urea nitrogen excretion as a result of exercise.Conclusions: Certain substrate and hormonal responses to exercise are altered as pregnancy progresses. Quantitatively, protein appears to be a relatively unimportant fuel during a 30-minute bout of moderate intensity exercise in this group of women evaluated during pregnancy and after delivery. Furthermore, a 30-minute bout of moderate intensity exercise would not be expected to compromise fetal amino acid availability. [ABSTRACT FROM AUTHOR]

Introduction: An in-depth understanding of the healthy cartilage response to activities of daily living is needed to better understand the complex relationship between cartilage health and loading. The purpose was to assess the role of loading on the acute serum cartilage oligomeric matrix protein (COMP) response in recreationally active individuals. Methods: Forty individuals without previous lower extremity injury participated in this repeated-measures study in which each participant completed all conditions during independent data collection sessions separated by at least 1 wk. An antecubital blood draw was performed before and after walking, drop-landing, and control (i.e., sitting) conditions. Commercially available enzyme-linked immunosorbent assays measured COMP concentration. The acute COMP response was quantified as the percent change of COMP concentration from before to after each condition. A one-way, repeated-measures ANOVA compared the acute COMP response between conditions. Post hoc Pearson product–moment correlation and chi-square analysis determined the relationship between the walking and drop-landing acute COMP response within individuals. Results: Acute COMP response was greater after walking (+4.2, P = 0.008) and drop landing (+4.6%, P = 0.002) compared with control (−2.3%), but did not differ between the walking and drop-landing conditions (P = 0.596). The magnitudes of the acute COMP response during walking and drop landing were correlated (r = 0.56, P < 0.001). However, the direction (i.e., either increase or decrease) of COMP was not the same after the walking and drop-landing conditions (χ1 = 0.870, P = 0.351). Conclusions: Walking and drop landing produced a greater acute COMP response when compared with a control condition in healthy individuals, but the acute COMP response was similar between the two physical activity conditions, although the conditions differed in magnitude and frequency of loading. [ABSTRACT FROM AUTHOR]

Objective: To examine the effects of exercise on serum estrogens, growth hormone, insulin, cortisol, lactate, and glucose levels in postmenopausal women receiving two routes of administration of estrogen replacement therapy (ERT).Design: Prospective, randomized, crossover study.Setting: The general clinical research center of an academic medical center.Patient(s): Eleven active, postmenopausal women.Intervention(s): The patients were screened with exercise stress testing, then oral micronized estradiol or transdermal estradiol was administered, followed by two 45-minute submaximal exercise tests. Dietary intake before the tests was standardized.Main Outcome Measure(s): The study measured maximal heart rate and aerobic power (V˙o2max), and serum levels of estradiol (E2), estrone (E1), cortisol, growth hormone (GH), insulin, glucose, and lactate.Result(s): Growth hormone, cortisol, and insulin all changed significantly in response to the 45-minute exercise bouts, but no differences were observed between the oral micronized estradiol and transdermal estradiol responses. E2 levels increased significantly during the transdermal estradiol 45-minute exercise bout; this change did not occur during the oral estradiol exercise bout. In the transdermal estradiol treatment group, the E2 levels at +30 and +45 minutes of exercise were elevated compared to the post-exercise levels at −15, 0, and 30 minutes. E1 was not significantly changed during the 45-minute exercise bouts in either group.Conclusion(s): During exercise, serum E2 levels rise significantly higher with transdermal but not oral routes of E2 administration. However, the elevated levels are not prolonged and normalize by 30 minutes after exercise. [Copyright &y& Elsevier]