Publications by authors named "Anthony C Hackney"

154 Publications

Menstrual Cycle Hormonal Changes and Energy Substrate Metabolism in Exercising Women: A Perspective.

Int J Environ Res Public Health 2021 Sep 24;18(19). Epub 2021 Sep 24.

Department of Exercise & Sport Science, University of North Carolina, Chapel Hill, NC 27599, USA.

This article discusses the research supporting that the hormonal changes across the menstrual cycle phases affect a woman's physiology during exercise, specifically addressing aspects of energy substrate metabolism and macro-nutrient utilization and oxidation. The overarching aim is to provide a perspective on what are the limitations of earlier research studies that have concluded such hormonal changes energy metabolism. Furthermore, suggestions are made concerning research approaches in future studies to increase the likelihood of providing evidence-based data in support of the perspective that menstrual cycle hormonal changes energy metabolism in exercising women.
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http://dx.doi.org/10.3390/ijerph181910024DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8508274PMC
September 2021

The effects of exercise training on plasma volume variations: A systematic review.

Int J Sports Med 2021 Oct 12. Epub 2021 Oct 12.

Higher Institute of Sport and Physical Education of Ksar-Saïd, Manouba, Tunisia., Higher Institute of Sport and Physical Education of Ksar-Saïd, Manouba, Tunisia., Tunis, Tunisia.

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
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http://dx.doi.org/10.1055/a-1667-6624DOI Listing
October 2021

The Effects of Aerobic-Resistance Training and Broccoli Supplementation on Plasma Dectin-1 and Insulin Resistance in Males with Type 2 Diabetes.

Nutrients 2021 Sep 9;13(9). Epub 2021 Sep 9.

M2S (Laboratoire Mouvement, Sport, Santé)-EA 1274, University of Rennes, F-35000 Rennes, France.

Background: This study aimed to evaluate the effects of a combination of aerobic-resistance training (CARET) and broccoli supplementation on dectin-1 levels and insulin resistance in men with type 2 diabetes mellitus (T2D).

Methods: Forty-four males with T2D were randomly allocated to four groups ( = 11 each group): CARET + broccoli supplement (TS), CARET + placebo (TP), control + broccoli supplement (S), and control + placebo (CP). CARET was performed three days per week for 12 weeks. TS and S groups received 10 g of broccoli supplement per day for 12 weeks. All variables were assessed at baseline and 12 weeks.

Results: Plasma dectin-1 levels were decreased in TS and TP groups compared with the CP group ( < 0.05). Cardiometabolic risk factors showed significant reductions in TP and TS groups compared to S and CP groups ( < 0.05).

Conclusion: The combination of CARET and broccoli supplementation produced the largest improvements in insulin resistance and dectin-1 and other complications of T2D.
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http://dx.doi.org/10.3390/nu13093144DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8471572PMC
September 2021

Hematology, Hormones, Inflammation, and Muscle Damage in Elite and Professional Soccer Players: A Systematic Review with Implications for Exercise.

Sports Med 2021 Aug 4. Epub 2021 Aug 4.

M2S (Laboratoire Mouvement, Sport, Santé)-EA 1274, University Rennes, 35000, Rennes, France.

Background: Knowledge of the long-term effects of soccer training on hematological, hormonal, inflammatory, and muscle damage markers and physical performance may help to better design strength and conditioning programs for performance development and injury prevention for the individual player and the team.

Objectives: The aim of this systematic review was to summarize and discuss evidence on the long-term effects of soccer training on selected hematological, hormonal, inflammatory, and muscle damage markers and physical performance in elite and professional soccer players. A second goal was to investigate associations between selected physiological markers and measures of performance.

Methods: Adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines, a systematic literature search was conducted in four electronic databases (PubMed, ISI Web of Knowledge, Web of Science, and SPORTDiscus) from inception until August 2020 to identify articles related to soccer training effects. To be included in this systematic review, studies had to examine male elite (national level) and/or professional (international level) soccer players aged > 17 years and a soccer training period > 4 weeks, and report outcomes related to hematological, hormonal, inflammatory, muscle damage, and performance markers.

Results: The search syntax initially identified 2420 records. After screening titles, abstracts, and full texts, 20 eligible studies were included in this systematic review, with training durations lasting between 4 and 18 weeks in 15 studies, around 6 months in four studies, and around 1 year in one study. Effects of long-term soccer training revealed parameter-specific increases or decreases in hematological, hormonal, inflammatory, and muscle damage markers and physical performance. Two studies showed a moderate increase in hematological markers such as hemoglobin (effect size [ES] = 0.67-0.93). Parameter-specific changes were noted for hormonal markers in the form of increases for total testosterone (ES = 0.20-0.67) and free testosterone (FT) (ES = 0.20-0.65) and decreases for cortisol (ES =  - 0.28 to - 1.31). Finally, moderate to very large increases were found for muscle damage markers such as creatine kinase (ES = 0.94-6.80) and physical performance such as countermovement jump (CMJ) height (ES = 0.50-1.11) and squat jump (SJ) height (ES = 0.65-1.28). After long-term periods of soccer training, significant positive correlations were found between percentage change (Δ%) in FT and Δ% in CMJ height (r = 0.94; p = 0.04) and between Δ% in total testosterone/cortisol (TT/C) ratio and Δ% in SJ (r = 0.89; p = 0.03).

Conclusions: Findings suggest that long-term soccer training induces increases/decreases in hematological, hormonal, inflammatory, and muscle damage markers and physical performance in male elite and professional soccer players. These fluctuations can be explained by different contextual factors (e.g., training load, duration of training, psychological factors, mood state). Interestingly, the observed changes in hormonal parameters (FT and TT/C) were related to vertical jump performance changes (e.g., CMJ and SJ). Anabolic hormones and TT/C can possibly be used as a tool to identify physical performance alteration after long-term soccer training.
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http://dx.doi.org/10.1007/s40279-021-01522-wDOI Listing
August 2021

High-intensity Interval Training Improves Lipocalin-2 and Omentin-1 Levels in Men with Obesity.

Int J Sports Med 2021 Jul 28. Epub 2021 Jul 28.

Univ Rennes, M2S (Laboratoire Mouvement, Sport, Santé) - EA 1274, F-35000 Rennes, France.

We investigated the effects of 12 weeks of high-intensity interval training (HIIT) on selected circulating adipokines and other cardiovascular diseases risks factors in men with obesity. Thirty men with obesity (age: 24.96±3.11 year, BMI: 30.92±1.04 kg/m) were randomly assigned to HIIT and control groups. The HIIT group participated in a 12-week HIIT program (5×2 min interval bout at an intensity of 85-95% HRmax interspersed by 1 min passive recovery, three times per week), while the control group maintained their usual lifestyles. Blood lipids, insulin resistance, and select serum adipokines were assessed before and after 12 weeks of the intervention period. HIIT improved body composition and lipid profiles (p<0.05) and also decreased fasting insulin levels (p=0.001) and HOMA-IR (p=0.002) levels. Furthermore, HIIT increased levels of lipocalin-2 (p=0.002) while decreasing omentin-1 levels (p=0.001) in men with obesity. Changes in lcn2 and omentin-1 concentrations correlated with the changes in risk factors in the HIIT group (p<0.05). The results indicate that 12 weeks of supervised HIIT significantly improves both circulating concentrations of lcn2 and omentin-1, two recently described adipokines, and risk markers of cardiovascular diseases in men with obesity. Further research is necessary to understand the molecular mechanisms involved with these changes.
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http://dx.doi.org/10.1055/a-1560-5401DOI Listing
July 2021

Exercise Endocrinology: "What Comes Next?"

Endocrines 2021 Sep 29;2(3):167-170. Epub 2021 Jun 29.

Musculoskeletal Physiology Research Group, Sport Health and Performance Enhancement (SHAPE) Research Centre, Nottingham Trent University, Nottingham NG11 8NS, UK.

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http://dx.doi.org/10.3390/endocrines2030017DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8294195PMC
September 2021

Energy Availability and RED-S Risk Factors in Competitive, Non-elite Male Endurance Athletes.

Transl Med Exerc Prescr 2021 7;1(1):25-32. Epub 2021 Jun 7.

Department of Exercise & Sport Science, University of North Carolina, Chapel Hill, NC 27599, USA.

Relative Energy Deficiency in Sport (RED-S) is predicated on the assumption that low energy availability (EA) induces deficiencies-dysfunction in multiple physiologic systems. However, research on RED-S and EA in male athletes is limited in comparison to women. The aim of this study is to investigate EA and the risk factors for RED-S, and their potential associations in non-elite male endurance athletes. Laboratory assessments for resting metabolic rate (RMR), bone mineral density (BMD), blood hormonal biomarkers and maximal aerobic capacity were conducted on 60 competitive, recreationally trained male endurance athletes (age=43.4±11.6 years [mean±SD], training=10.9±2.7 h/wk, 7.1±8.8 years). Participants provided 7-days of training logs and 4-days of diet records. Diet and training records were used to calculate EA. Correlations were used to examine associations between EA and RMR, BMD, stress fractures and reproductive, metabolic and bone biomarkers. Mean EA was 28.7±13.4 kcal/kg fat free mass (FFM), which categorized our sample as low EA (based upon published criterion, < 30 kcal/kg FFM) and at a high risk for RED-S. Hormonal and bone biomarkers were in normal clinical ranges, even though EA was low. The only interesting significant association was EA being negatively associated with total body BMD ( = -0.360, =0.005), opposite of expectations. On average our subjects displayed a state of low EA based upon the criterion which has been primarily developed from female-based research. Nonetheless, our participants displayed no major hormonal or bone health disturbances found in athletes diagnosed with RED-S. A value of < 30 kcal/kg FFM to diagnose low EA may not be appropriate for non-elite endurance trained men.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8294781PMC
June 2021

Association between ACTN3 R577X genotype and risk of non-contact injury in trained athletes: A systematic review.

J Sport Health Sci 2021 Jul 17. Epub 2021 Jul 17.

Higher Institute of Sport and Physical Education, Ksar-Said, University of Manouba, Tunis 2010, Tunisia.

Background: The aim of this study was to review, systematically, evidence concerning the link between the ACTN3 R577X polymorphism and the rates and severity of non-contact injuries and exercise-induced muscle damage in athletes and individuals enrolled in exercise training programs.

Methods: A computerized literature search was performed in the electronic databases PubMed, Web of Science, and SPORTDiscus, from inception until November 2020. All included studies compared the epidemiological characteristics of non-contact injury between the different genotypes of the ACTN3 R577X polymorphism.

Results: Our search identified 492 records. After the screening of titles, abstracts, and full texts, 13 studies examining the association between the ACTN3 genotypes and the rate and severity of non-contact injury were included in the analysis. These studies were performed in 6 different countries (Spain, Japan, Brazil, China, Republic of Korea, and Italy) and involved a total participant pool of 1093 participants. Of the studies, 2 involved only women, 5 involved only men, and 6 involved both men and women. All the studies included were classified as high-quality studies (≥6 points on the Physiotherapy Evidence Database [PEDro] scale). Overall, evidence suggests there is an association between the ACTN3 R577X genotype and non-contact injury in 12 investigations. Six studies observed a significant association between ACTN3 R577X polymorphism and exercise induced muscle damage: 2 with non-contact ankle injury, 3 with non-contact muscle injury, and 1 with overall non-contact injury.

Conclusion: The present findings support the premise that possessing the ACTN3 XX genotype may predispose athletes to a higher probability of some non-contact injuries, such as muscle injury, ankle sprains, and higher levels of exercise-induced muscle damage.
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http://dx.doi.org/10.1016/j.jshs.2021.07.003DOI Listing
July 2021

Influence of Menstrual Cycle Estradiol-β-17 Fluctuations on Energy Substrate Utilization-Oxidation during Aerobic, Endurance Exercise.

Int J Environ Res Public Health 2021 07 5;18(13). Epub 2021 Jul 5.

Department of Exercise & Sport Science, University of North Carolina, Chapel Hill, NC 27599, USA.

This study examined the effect of estradiol-β-17 across the menstrual cycle (MC) during aerobic exercise on energy substrate utilization and oxidation. Thirty-two eumenorrheic (age = 22.4 ± 3.8 y (mean ± SD)), physically active women participated in two steady-state running sessions at 65% of VO, one during the early follicular and one during the luteal phase of the MC. Blood samples were collected at rest before each exercise session and analyzed for Estradiol-β-17 to confirm the MC phase. Carbohydrate (CHO) utilization and oxidation values were significantly lower ( < 0.05) in the luteal (utilization: 51.6 ± 16.7%; oxidation: 1.22 ± 0.56 g/min; effect size (ES) = 0.45, 0.27) than follicular phase (utilization: 58.2 ± 15.1%; oxidation: 1.38 ± 0.60 g/min) exercise sessions. Conversely, fat utilization and oxidation values were significantly ( < 0.05) higher in the luteal (utilization: 48.4 ± 16.7%; oxidation: 0.49 ± 0.19 g/min; ES = 0.45,0.28) than follicular phase (utilization: 41.8 ± 15.1%; oxidation: 0.41 ± 0.14 g/min). Estradiol-β-17 concentrations were significantly ( < 0.01) greater during the luteal (518.5 ± 285.4 pmol/L; ES = 0.75) than follicular phase (243.8 ± 143.2 pmol/L). Results suggest a greater use of fat and reduced amount of CHO usage during the luteal versus follicular phase, directly related to the change in resting estradiol-β-17. Future research should investigate the role these changes may play in female athletic performance.
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http://dx.doi.org/10.3390/ijerph18137209DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8295741PMC
July 2021

The Effects of Eccentric and Plyometric Training Programs and Their Combination on Stability and the Functional Performance in the Post-ACL-Surgical Rehabilitation Period of Elite Female Athletes.

Front Physiol 2021 2;12:688385. Epub 2021 Jul 2.

Tunisian Research Laboratory "Sport Performance Optimization", National Center of Medicine and Science in Sports, Tunis, Tunisia.

Background: The standard method to treat physically active patients with anterior cruciate ligament (ACL) rupture is ligament reconstruction surgery. The rehabilitation training program is very important to improve functional performance in recreational athletes following ACL reconstruction.

Objectives: The aims of this study were to compare the effects of three different training programs, eccentric training (ECC), plyometric training (PLYO), or combined eccentric and plyometric training (COMB), on dynamic balance (Y-BAL), the Lysholm Knee Scale (LKS), the return to sport index (RSI), and the leg symmetry index (LSI) for the single leg hop test for distance in elite female athletes after ACL surgery.

Materials And Methods: Fourteen weeks after rehabilitation from surgery, 40 elite female athletes (20.3 ± 3.2 years), who had undergone an ACL reconstruction, participated in a short-term (6 weeks; two times a week) training study. All participants received the same rehabilitation protocol prior to the training study. Athletes were randomly assigned to three experimental groups, ECC ( = 10), PLYO ( = 10), and COMB ( = 10), and to a control group (CON: = 10). Testing was conducted before and after the 6-week training programs and included the Y-BAL, LKS, and RSI. LSI was assessed after the 6-week training programs only.

Results: Adherence rate was 100% across all groups and no training or test-related injuries were reported. No significant between-group baseline differences (pre-6-week training) were observed for any of the parameters. Significant group-by-time interactions were found for Y-BAL ( < 0.001, ES = 1.73), LKS ( < 0.001, ES = 0.76), and RSI ( < 0.001, ES = 1.39). Contrast analysis demonstrated that COMB yielded significantly greater improvements in Y-BAL, LKS, and RSI (all < 0.001), in addition to significantly better performances in LSI (all < 0.001), than CON, PLYO, and ECC, respectively.

Conclusion: In conclusion, combined (eccentric/plyometric) training seems to represent the most effective training method as it exerts positive effects on both stability and functional performance in the post-ACL-surgical rehabilitation period of elite female athletes.
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http://dx.doi.org/10.3389/fphys.2021.688385DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8283277PMC
July 2021

Association Between Mental Imagery and Change of Direction Performance in Young Elite Soccer Players of Different Maturity Status.

Front Psychol 2021 10;12:665508. Epub 2021 Jun 10.

Higher Institute of Sport and Physical Education of Ksar-Said, University of La Manouba, Tunis, Tunisia.

Previous studies have not considered the potential influence of maturity status on the relationship between mental imagery and change of direction (CoD) speed in youth soccer. Accordingly, this cross-sectional study examined the association between mental imagery and CoD performance in young elite soccer players of different maturity status. Forty young male soccer players, aged 10-17 years, were assigned into two groups according to their predicted age at peak height velocity (PHV) (Pre-PHV; = 20 and Post-PHV; = 20). Participants were evaluated on soccer-specific tests of CoD with (CoDBall-15m) and without (CoD-15m) the ball. Participants completed the movement imagery questionnaire (MIQ) with the three- dimensional structure, internal visual imagery (IVI), external visual imagery (EVI), as well as kinesthetic imagery (KI). The Post-PHV players achieved significantly better results than Pre-PHV in EVI ( = 1.58, large; < 0.001), CoD-15m ( = 2.09, very large; < 0.001) and CoDBall-15m ( = 1.60, large; < 0.001). Correlations were significantly different between maturity groups, where, for the pre-PHV group, a negative very large correlation was observed between CoDBall-15m and KI ( = -0.73, = 0.001). For the post-PHV group, large negative correlations were observed between CoD-15m and IVI ( = -0.55, = 0.011), EVI ( = -062, = 0.003), and KI ( = -0.52, = 0.020). A large negative correlation of CoDBall-15m with EVI ( = -0.55, = 0.012) and very large correlation with KI ( = -0.79, = 0.001) were also observed. This study provides evidence of the theoretical and practical use for the CoD tasks stimulus with imagery. We recommend that sport psychology specialists, coaches, and athletes integrated imagery for CoD tasks in pre-pubertal soccer players to further improve CoD related performance.
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http://dx.doi.org/10.3389/fpsyg.2021.665508DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8222513PMC
June 2021

Improvement of Physical Performance Following a 6 Week Change-of-Direction Training Program in Elite Youth Soccer Players of Different Maturity Levels.

Front Physiol 2021 24;12:668437. Epub 2021 May 24.

Tunisian Research Laboratory, Sport Performance Optimization, National Center of Medicine and Science in Sports (CNMSS), Tunis, Tunisia.

Change-of-direction (CoD) is a necessary physical ability of a field sport and may vary in youth players according to their maturation status. The aim of this study is: to compare the effectiveness of a 6-week CoD training intervention on dynamic balance (CS-YBT), horizontal jump (5JT), speed (10 and 30-m linear sprint times), CoD with (15 m-CoD + B) and without (15 m-CoD) the ball, in youth male soccer players at different levels of maturity [pre- and post-peak height velocity (PHV)]. Thirty elite male youth soccer players aged 10-17 years from the Tunisian first division participated in this study. The players were divided into pre- (G1, = 15) and post-PHV (G2, = 15) groups. Both groups completed a similar 6-week training program with two sessions per week of four CoD exercises. All players completed the following tests before and after intervention: CS-YBT; 5 JT; 10, 30, and 15 m-CoD; and 15 m-CoD + B, and data were analyzed using ANCOVA. All 30 players completed the study according to the study design and methodology. Adherence rate was 100% across all groups, and no training or test-related injuries were reported. Pre-PHV and post-PHV groups showed significant amelioration post-intervention for all dependent variables (after test > before test; < 0.01, = 0.09-1.51). ANOVA revealed a significant group × time interaction only for CS-YBT ( = 4.45; < 0.04; η = 0.14), 5JT ( = 6.39; < 0.02; η = 0.18), and 15 m-CoD ( = 7.88; < 0.01; η = 0.22). CS-YBT, 5JT, and 15 m-CoD improved significantly in the post-PHV group (+ 4.56%, effect size = 1.51; + 4.51%, effect size = 1.05; and -3.08%, effect size = 0.51, respectively), more than the pre-PHV group (+ 2.77%, effect size = 0.85; + 2.91%, effect size = 0.54; and -1.56%, effect size = 0.20, respectively). The CoD training program improved balance, horizontal jump, and CoD without the ball in male preadolescent and adolescent soccer players, and this improvement was greater in the post-PHV players. The maturity status of the athletes should be considered when programming CoD training for soccer players.
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http://dx.doi.org/10.3389/fphys.2021.668437DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8181750PMC
May 2021

Performance and Health Decrements Associated With Relative Energy Deficiency in Sport for Division I Women Athletes During a Collegiate Cross-Country Season: A Case Series.

Front Endocrinol (Lausanne) 2021 12;12:524762. Epub 2021 May 12.

Neuroendocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States.

The purpose of this case series was to evaluate the presence of low Energy Availability (EA) and its impact on components of Relative Energy Deficiency in Sport (RED-S) in a population of female collegiate runners. Seven female NCAA Division I athletes (age: 22.3 ± 1.5 yrs; height: 169.7 ± 5.7 cm; weight: 58.3 ± 4.1 kg) were tracked from August until February, covering the beginning (Pre XC), end (Post XC) of their competitive cross country season, and beginning of the following track season (Pre Track). The athletes were assessed for female athlete triad (Triad) risk, energy availability, body composition, resting metabolic rate (RMR), nutritional intake, and blood markers (including vitamin D, ferritin, and triiodothyronine (T3)). From Pre XC to Post XC there were no significant differences in body mass, fat free mass or body fat percentage. At Pre XC, mean EA was 31.6 ± 13.3 kcal/kg FFM∙d. From Post XC to Pre Track, there was a significant increase in body mass (59.1 ± 5.1 to 60.6 ± 5.7 kg, p<0.001,d=0.27). From Post XC to Pre Track, there was a significant increase in RMR (1466 ± 123.6 to 1614.6 ± 89.1 kcal·d, p<0.001,d=2.6). For 25(OH) vitamin D, there was a significant reduction from Pre XC to Post XC (44.1 ± 10.6 39.5 ± 12.2 ng·mL, p=0.047,d=-0.4), and a significant increase from Post XC to Pre Track (39.5 ± 12.2 48.1 ± 10.4 ng·mL, p=0.014,d=0.75). For ferritin, there was a trend towards a decrease from Pre XC to Post XC (24.2 ± 13.2 15.7 ± 8.8 ng·mL, p=0.07, d=-0.75), as well as a trend toward an increase from Post XC to Pre Track (15.7 ± 8.8 34.1 ± 18.0 ng·mL, p=0.08, d=1.3). No differences in T3 were observed across time points. Average Triad risk score was 2.3 ± 1.4. Notably, 5 of 7 athletes met criteria for moderate risk. Despite many athletes meeting criteria for low EA and having elevated Triad risk assessment scores, most were able to maintain body mass and RMR. One athlete suffered severe performance decline and a reduced RMR. Surprisingly, she was the only athlete above the recommended value for ferritin. Following increased nutritional intake and reduced training volume, her performance and RMR recovered. Changes in body mass and body composition were not indicative of the presence of other concerns associated with RED-S. This exploratory work serves as a guide for future, larger studies for tracking athletes, using RMR and nutritional biomarkers to assess RED-S.
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http://dx.doi.org/10.3389/fendo.2021.524762DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8149996PMC
May 2021

Sex-specific effects of small-sided games in basketball on psychometric and physiological markers during Ramadan intermittent fasting: a pilot study.

BMC Sports Sci Med Rehabil 2021 May 23;13(1):56. Epub 2021 May 23.

M2S (Laboratoire Mouvement, Sport, Santé) - EA 1274, University of Rennes, F-35000, Rennes, France.

Background: We assessed the effects of gender, in association with a four-week small-sided games (SSGs) training program, during Ramadan intermitting fasting (RIF) on changes in psychometric and physiological markers in professional male and female basketball players.

Methods: Twenty-four professional basketball players from the first Tunisian (Tunisia) division participated in this study. The players were dichotomized by sex (males [G = 12]; females [G = 12]). Both groups completed a 4 weeks SSGs training program with 3 sessions per week. Psychometric (e.g., quality of sleep, fatigue, stress, and delayed onset of muscle soreness [DOMS]) and physiological parameters (e.g., heart rate frequency, blood lactate) were measured during the first week (baseline) and at the end of RIF (post-test).

Results: Post hoc tests showed a significant increase in stress levels in both groups (G [- 81.11%; p < 0.001, d = 0.33, small]; G [- 36,53%; p = 0.001, d = 0.25, small]). Concerning physiological parameters, ANCOVA revealed significantly lower heart rates in favor of G at post-test (1.70%, d = 0.38, small, p = 0.002).

Conclusions: Our results showed that SSGs training at the end of the RIF negatively impacted psychometric parameters of male and female basketball players. It can be concluded that there are sex-mediated effects of training during RIF in basketball players, and this should be considered by researchers and practitioners when programing training during RIF.
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http://dx.doi.org/10.1186/s13102-021-00285-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8141155PMC
May 2021

Effects of different resistance training frequencies on body composition and muscular performance adaptations in men.

PeerJ 2021 21;9:e10537. Epub 2021 Apr 21.

M2S (Laboratoire Mouvement, Sport, Santé) - EA 1274, Univ Rennes, Rennes, France.

Background: The aim of this study was to compare the effects of 8 weeks resistance training (RT) with two sessions versus four sessions per week under volume load-equated conditions on body composition, maximal strength, and explosive actions performance in recreationally trained men.

Methods: Thirty-five healthy young men participated in the study and were randomly divided into a two sessions per-week RT (RT2, = 12), four sessions per-week RT (RT4, = 13) or a control group (CG, = 10). All subjects were evaluated for thigh, chest and arm circumference, countermovement jump (CMJ), medicine ball throw (MBT), 1-repetition maximum (1RM) leg press, bench press, arm curl, muscular endurance (i.e., 60% of 1RM to failure) for leg press, and bench press at pre, mid (week 4) and post an 8-week training intervention.

Results: A two-way analysis of variance with repeated measures (3 [group] × 3 [time]) revealed that both training groups increased chest and thigh circumferences, strength and explosive actions performance tests in comparison to CG following 8 weeks of training ( = 0.01 to 0.04). Group × time interactions were also noted in 1RM bench press (effects size [ES] = 1.07 vs. 0.89) and arm curl (ES = 1.15 vs. 0.89), with greater gains for RT4 than RT2 ( = 0.03).

Conclusion: RT improved muscle strength, explosive actions performance and markers of muscle size in recreationally trained men; however, four sessions of resistance training per week produced greater gains in muscular strength for the upper body measures (i.e., 1RM bench press and arm curl) when compared to two sessions per week under volume-equated conditions.
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http://dx.doi.org/10.7717/peerj.10537DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8067909PMC
April 2021

Influence of Menstrual Cycle or Hormonal Contraceptive Phase on Energy Intake and Metabolic Hormones-A Pilot Study.

Endocrines 2021 Jun 16;2(2):79-90. Epub 2021 Apr 16.

Faculty of Sport and Health Sciences, University of Jyväskylä, 40014 Jyväskylä, Finland.

Sex hormones are suggested to influence energy intake (EI) and metabolic hormones. This study investigated the influence of menstrual cycle (MC) and hormonal contraceptive (HC) cycle phases on EI, energy availability (EA), and metabolic hormones in recreational athletes (eumenorrheic, NHC = 15 and monophasic HC-users, CHC = 9). In addition, 72-h dietary and training logs were collected in addition to blood samples, which were analyzed for 17β-estradiol (E2), progesterone (P4), leptin, total ghrelin, insulin, and tri-iodothyronine (T3). Measurements were completed at four time-points (phases): Bleeding, mid-follicular (FP)/active 1, ovulation (OVU)/active 2, mid-luteal (LP)/inactive in NHC/CHC, respectively. As expected, E2 and P4 fluctuated significantly in NHC ( < 0.05) and remained stable in CHC. In NHC, leptin increased significantly between bleeding and ovulation ( = 0.030) as well as between FP and OVU ( = 0.022). No group differences in other measured hormones were observed across the MC and HC cycle. The mean EI and EA were similar between phases, with no significant differences observed in macronutrient intake over either the MC or HC. While the MC phase might have a small, but statistically significant effect on leptin, the findings of the present study suggest that the MC or HC phase does not significantly alter ad libitum EI or EA in recreational athletes.
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http://dx.doi.org/10.3390/endocrines2020008DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8096184PMC
June 2021

Physical activity and adipokine levels in individuals with type 2 diabetes: A literature review and practical applications.

Rev Endocr Metab Disord 2021 Apr 30. Epub 2021 Apr 30.

Department of Physical Education and Sport Sciences, University of Kurdistan, Sanandaj, Iran.

We review the effects of acute and long-term physical activity on adipokine levels in individuals with type 2 diabetes (T2D). Three electronic databases were searched. Studies made in animal models were excluded, while studies based on participants with and without T2D, and also studies with type 1 diabetes were included. Of the 2,450 citations, 63 trials, including randomised control trials, cross-sectional and longitudinal studies, met our inclusion criteria. Seventy and five percent of studies reported the effects of physical activity on tumor necrosis factor-alpha (TNFα), interleukin 6 (IL-6), adiponectin, visfatin, omentin-1, and leptin levels. There are no robust results due to variations in exercise modality, intensity, duration, and also differences in cohort characteristics in the literature. Only four studies described the effects of an acute session of physical activity on adipokine levels. Overall, physical activity improves diabetes status by regulating adipokine levels. However, long-term aerobic + resistance training combined with dietary modifications is likely to be a more effective strategy for improving adipokines profiles in patients with type 2 diabetes.
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http://dx.doi.org/10.1007/s11154-021-09657-xDOI Listing
April 2021

Exercise as a Therapeutic Intervention in Gestational Diabetes Mellitus.

Endocrines 2021 Jun 26;2(2):65-78. Epub 2021 Mar 26.

Department of Exercise & Sport Science, Department of Nutrition, University of North Carolina, Chapel Hill, North Carolina, NC 27599-8700, USA.

Gestational Diabetes Mellitus (GDM) is defined as any degree of glucose intolerance with onset or first recognition during pregnancy. Regular exercise is important for a healthy pregnancy and can lower the risk of developing GDM. For women with GDM, exercise is safe and can affect the pregnancy outcomes beneficially. A single exercise bout increases skeletal muscle glucose uptake, minimizing hyperglycemia. Regular exercise training promotes mitochondrial biogenesis, improves oxidative capacity, enhances insulin sensitivity and vascular function, and reduces systemic inflammation. Exercise may also aid in lowering the insulin dose in insulin-treated pregnant women. Despite these benefits, women with GDM are usually inactive or have poor participation in exercise training. Attractive individualized exercise programs that will increase adherence and result in optimal maternal and offspring benefits are needed. However, as women with GDM have a unique physiology, more attention is required during exercise prescription. This review (i) summarizes the cardiovascular and metabolic adaptations due to pregnancy and outlines the mechanisms through which exercise can improve glycemic control and overall health in insulin resistance states, (ii) presents the pathophysiological alterations induced by GDM that affect exercise responses, and (iii) highlights cardinal points of an exercise program for women with GDM.
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http://dx.doi.org/10.3390/endocrines2020007DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8046020PMC
June 2021

Methodological Considerations for Studies in Sport and Exercise Science with Women as Participants: A Working Guide for Standards of Practice for Research on Women.

Sports Med 2021 May 16;51(5):843-861. Epub 2021 Mar 16.

Department of Exercise and Sport Science; Department of Nutrition, University of North Carolina, Chapel Hill, NC, USA.

Until recently, there has been less demand for and interest in female-specific sport and exercise science data. As a result, the vast majority of high-quality sport and exercise science data have been derived from studies with men as participants, which reduces the application of these data due to the known physiological differences between the sexes, specifically with regard to reproductive endocrinology. Furthermore, a shortage of specialist knowledge on female physiology in the sport science community, coupled with a reluctance to effectively adapt experimental designs to incorporate female-specific considerations, such as the menstrual cycle, hormonal contraceptive use, pregnancy and the menopause, has slowed the pursuit of knowledge in this field of research. In addition, a lack of agreement on the terminology and methodological approaches (i.e., gold-standard techniques) used within this research area has further hindered the ability of researchers to adequately develop evidenced-based guidelines for female exercisers. The purpose of this paper was to highlight the specific considerations needed when employing women (i.e., from athletes to non-athletes) as participants in sport and exercise science-based research. These considerations relate to participant selection criteria and adaptations for experimental design and address the diversity and complexities associated with female reproductive endocrinology across the lifespan. This statement intends to promote an increase in the inclusion of women as participants in studies related to sport and exercise science and an enhanced execution of these studies resulting in more high-quality female-specific data.
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http://dx.doi.org/10.1007/s40279-021-01435-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8053180PMC
May 2021

Body Composition, Energy Availability, Training, and Menstrual Status in Female Runners.

Int J Sports Physiol Perform 2021 Mar 9;16(7):1043-1048. Epub 2021 Mar 9.

Purpose: To determine body composition, energy availability, training load, and menstrual status in young elite endurance running athletes (ATH) over 1 year, and in a secondary analysis, to investigate how these factors differ between nonrunning controls (CON), and amenorrheic (AME) and eumenorrheic (EUM) ATH. Correlations to injury, illness, and performance were also examined.

Methods: Altogether 13 ATH and 8 CON completed the Low Energy Availability in Females Questionnaire. Anthropometric, energy intake, and peak oxygen uptake assessments were made at 4 time points throughout the year: at baseline post competition season, post general preparation, post specific preparation, and post competition season the following year. Logs of physical activity, menstrual cycle, illness, and injury were kept by all participants. Performance was defined using the highest International Association of Athletics Federations points prior to and after the study.

Results: ATH had significantly lower body mass (P < .008), fat percentage (P < .001), and body mass index (P < .027) compared with CON, while energy availability did not differ between ATH and CON. The Low Energy Availability in Females Questionnaire score was higher in ATH than in CON (P < .028), and 8 ATH (vs zero CON) were AME. The AME had significantly more injury days (P < .041) and ran less (P < .046) than EUM, while total annual running distance was positively related to changes in performance in ATH (r < .62, P < .043, n < 11).

Conclusions: More than half of this group of runners was AME, and they were injured more and ran less than their EUM counterparts. Furthermore, only the EUM runners increased their performance over the course of the year.
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http://dx.doi.org/10.1123/ijspp.2020-0276DOI Listing
March 2021

Hormonal Exercise Response Model (HERM): A Conceptual Framework of Endocrine Reactivity to the Physical Stress of Exercise.

Anatol Sport Res 2020 25;1(1):1-4. Epub 2020 Dec 25.

Department of Exercise & Sport Science; Department of Nutrition University of North Carolina, Chapel Hill, North Carolina, USA.

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http://dx.doi.org/10.29228/anatoliasr.1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7889060PMC
December 2020

Walking exercise and lower-body blood flow restriction: Effects on systemic inflammation, lipid profiles and hematological indices in overweight middle-aged males.

Res Sports Med 2021 Feb 16:1-9. Epub 2021 Feb 16.

Univ Rennes, M2S (Laboratoire Mouvement, Sport, Santé) - EA 1274, Rennes, France.

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 ( = 9) or no-BFR ( = 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 ( ≤ 0.05) that were accompanied by changes in red blood cells (RBC), haemoglobin (HGB) and haematocrit (HCT) levels ( ≤ 0.05). RBC levels were increased in the BFR group ( ≤ 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.
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http://dx.doi.org/10.1080/15438627.2021.1888100DOI Listing
February 2021

Oral Contraceptives Do Not Affect Physiological Responses to Strength Exercise.

J Strength Cond Res 2021 Apr;35(4):894-901

Department for Molecular and Cellular Sports Medicine, Institute of Cardiovascular Research and Sports Medicine, German Sport University Cologne, Cologne, Germany.

Abstract: Umlauff, L, Weil, P, Zimmer, P, Hackney, AC, Bloch, W, and Schumann, M. Oral contraceptives do not affect physiological responses to strength exercise. J Strength Cond Res 35(4): 894-901, 2021-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 × 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 as p ≤ 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 × 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.
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http://dx.doi.org/10.1519/JSC.0000000000003958DOI Listing
April 2021

Validation of a Commercially Available Markerless Motion-Capture System for Trunk and Lower Extremity Kinematics During a Jump-Landing Assessment.

J Athl Train 2021 Jan 22. Epub 2021 Jan 22.

Department of Exercise and Sport Science, Gillings School of Global Public Health, University of North Carolina at Chapel Hill.

Context: Field-based, portable motion-capture systems can be used to help identify individuals at greater risk of lower extremity injury. Microsoft Kinect-based markerless motion-capture systems meet these requirements; however, until recently, these systems were generally not automated, required substantial data postprocessing, and were not commercially available.

Objective: To validate the kinematic measures of a commercially available markerless motion-capture system.

Design: Descriptive laboratory study.

Setting: Laboratory.

Patients Or Other Participants: A total of 20 healthy, physically active university students (10 males, 10 females; age = 20.50 ± 2.78 years, height = 170.36 ± 9.82 cm, mass = 68.38 ± 10.07 kg, body mass index = 23.50 ± 2.40 kg/m2).

Intervention(s): Participants completed 5 jump-landing trials. Kinematic data were simultaneously recorded using Kinect-based markerless and stereophotogrammetric motion-capture systems.

Main Outcome Measure(s): Sagittal- and frontal-plane trunk, hip-joint, and knee-joint angles were identified at initial ground contact of the jump landing (IC), for the maximum joint angle during the landing phase of the initial landing (MAX), and for the joint-angle displacement from IC to MAX (DSP). Outliers were removed, and data were averaged across trials. We used intraclass correlation coefficients (ICCs [2,1]) to assess intersystem reliability and the paired-samples t test to examine mean differences (α ≤ .05).

Results: Agreement existed between the systems (ICC range = -1.52 to 0.96; ICC average = 0.58), with 75.00% (n = 24/32) of the measures being validated (P ≤ .05). Agreement was better for sagittal- (ICC average = 0.84) than frontal-plane (ICC average = 0.35) measures. Agreement was best for MAX (ICC average = 0.77) compared with IC (ICC average = 0.56) and DSP (ICC average = 0.41) measures. Pairwise comparisons identified differences for 18.75% (6/32) of the measures. Fewer differences were observed for sagittal- (0.00%; 0/15) than for frontal-plane (35.29%; 6/17) measures. Between-systems differences were equivalent for MAX (18.18%; 2/11), DSP (18.18%; 2/11), and IC measures (20.00%; 2/10). The markerless system underestimated sagittal-plane measures (86.67%; 13/15) and overestimated frontal-plane measures (76.47%; 13/17). No trends were observed for overestimating or underestimating IC, MAX, or DSP measures.

Conclusions: Moderate agreement existed between markerless and stereophotogrammetric motion-capture systems. Better agreement existed for larger (eg, sagittal plane, MAX) than for smaller (eg, frontal plane, IC) joint angles. The DSP angles had the worst agreement. Markerless motion-capture systems may help clinicians identify individuals at greater risk of lower extremity injury.
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http://dx.doi.org/10.4085/1062-6050-0023.20DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7901583PMC
January 2021

Effects of Combined Balance and Strength Training on Measures of Balance and Muscle Strength in Older Women With a History of Falls.

Front Physiol 2020 23;11:619016. Epub 2020 Dec 23.

Higher Institute of Sport and Physical Education, Ksar-said, University of Manouba, Manouba, Tunisia.

Objective: We investigated the effects of combined balance and strength training on measures of balance and muscle strength in older women with a history of falls.

Methods: Twenty-seven older women aged 70.4 ± 4.1 years (age range: 65 to 75 years) were randomly allocated to either an intervention (IG, = 12) or an active control (CG, = 15) group. The IG completed 8 weeks combined balance and strength training program with three sessions per week including visual biofeedback using force plates. The CG received physical therapy and gait training at a rehabilitation center. Training volumes were similar between the groups. Pre and post training, tests were applied for the assessment of muscle strength (weight-bearing squat [WBS] by measuring the percentage of body mass borne by each leg at different knee flexions [0°, 30°, 60°, and 90°], sit-to-stand test [STS]), and balance. Balance tests used the modified clinical test of sensory interaction (mCTSIB) with eyes closed (EC) and opened (EO), on stable (firm) and unstable (foam) surfaces as well as spatial parameters of gait such as step width and length (cm) and walking speed (cm/s).

Results: Significant group × time interactions were found for different degrees of knee flexion during WBS (0.0001 < < 0.013, 0.441 < < 0.762). tests revealed significant pre-to-post improvements for both legs and for all degrees of flexion (0.0001 < < 0.002, 0.697 < < 1.875) for IG compared to CG. Significant group × time interactions were found for firm EO, foam EO, firm EC, and foam EC (0.006 < < 0.029; 0.302 < < 0.518). tests showed significant pre-to-post improvements for both legs and for all degrees of oscillations (0.0001 < < 0.004, 0.753 < < 2.097) for IG compared to CG. This study indicates that combined balance and strength training improved percentage distribution of body weight between legs at different conditions of knee flexion (0°, 30°, 60°, and 90°) and also decreased the sway oscillation on a firm surface with eyes closed, and on foam surface (with eyes opened or closed) in the IG.

Conclusion: The higher positive effects of training seen in standing balance tests, compared with dynamic tests, suggests that balance training exercises including lateral, forward, and backward exercises improved static balance to a greater extent in older women.
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http://dx.doi.org/10.3389/fphys.2020.619016DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7786296PMC
December 2020

Resistance training, gremlin 1 and macrophage migration inhibitory factor in obese men: a randomised trial.

Arch Physiol Biochem 2020 Dec 28:1-9. Epub 2020 Dec 28.

Univ Rennes, M2S (Laboratoire Mouvement, Sport, Santé) - EA 1274, Rennes, France.

Objective: This study aimed to determine how different resistance training protocols affect gremlin 1, macrophage migration inhibitory factor (MIF), cardiometabolic, and anthropometric measures in obese men.

Methods: Forty-four males with obesity (weight: 93.2 ± 2.2 kg, BMI: 32.9 ± 1.2 kg/m, age: 27.5 ± 9.4 years) were randomly assigned to traditional resistance training (TRT,  = 11), circuit resistance training (CRT,  = 11), interval resistance training (IRT,  = 11) or control (C,  = 11) groups. TRT group performed ten exercises at 50% of 1RM with 14 repetitions for three sets and 30 seconds rest interval between exercises and 1.5 min rest between sets, the CRT protocol included three circuits of 10 exercises, at an intensity of 50% of 1-RM, 14 repetitions with a minimum rest (< 15 s) between exercises and 3 min rest between sets, and the IRT group performed two sets of the same exercises with 50% of 1 RM, and 14 repetitions were followed with active rest of 25% of 1RM and 14 repetitions. All resistance training groups performed 60 min per session resistance exercises, 3 days per week, for 12 weeks. Measurements were taken at baseline and after 12 weeks of exercise training.

Results: Resistance training (TRT, CRT, and IRT) significantly decreased plasma levels of gremlin (TRT from 231.0 ± 5.8 to 210.0 ± 11.6 ng/ml, CRT from 226.0 ± 7.6 to 188.0 ± 7.7 ng/ml and, IRT from 227.0 ± 6.3 to 183.0 ± 9.0 ng/ml, effect size (ES): 0.50), MIF (TRT from 251.0 ± 7.4 to 260.0 ± 6.5 ng/ml, CRT from 248.0 ± 10.9 to 214.0 ± 9.0 ng/ml and, IRT from 247.0 ± 8.9 to 196.0 ± 6.9 ng/ml, ES: 0.55) and CRP (TRT from 28.4 ± 1.7 to 23.3 ± 2.1 nmol/l, CRT from 28.5 ± 2.2 to 21.1 ± 1.8 nmol/l, IRT from 28.1 ± 1.3 to 20.8 ± 1.3 nmol/l, ES: 0.49) compared to the control group ( < .05), but these reduction were greater in the CRT and IRT groups compared to the TRT group ( < .05).

Conclusion: The CRT and IRT protocols had more beneficial improvement in gremlin 1, MIF, body composition, and cardiometabolic risk factors compared to the beneficial changes produced by TRT protocol.
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http://dx.doi.org/10.1080/13813455.2020.1856142DOI Listing
December 2020

Human chorionic gonadotropin treatment: a viable option for management of secondary hypogonadism and male infertility.

Expert Rev Endocrinol Metab 2021 Jan 21;16(1):1-8. Epub 2020 Dec 21.

Graduate School of Medicine, Department of Urology, Juntendo University , Tokyo, Japan.

: Low testosterone and its symptoms is a condition affecting many males with severe repercussions on health. Testosterone affects metabolism, bones, joints, and ligaments, the cardiovascular system, liver, sexual functions, muscle mass, and the nervous system. Nowadays, due to recent research showing the benefits of testosterone replacement therapy, this treatment is gaining in popularity among aging men. However, testosterone replacement can increase the risk of infertility. : Human chorionic gonadotropin (HCG) is used in the treatment of male infertility due to its luteinizing hormone (LH)-like action triggering testosterone and sperm production. Due to these positive effects on testosterone production, HCG has also been used to treat secondary hypogonadism. In this review, based on a literature review for the years 1977-2020 via Google Scholar, we summarize the current research on HCG as treatment for patients suffering from low testosterone and provide an overview of the pros and contras for HCG therapy as compared to testosterone replacement therapy for the treatment of secondary hypogonadism. : The testosterone and sperm production triggering effects of HCG without the side effects on fertility seen in testosterone replacement therapy make HCG therapy a prime candidate for patients suffering from secondary hypogonadism.
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http://dx.doi.org/10.1080/17446651.2021.1863783DOI Listing
January 2021

Sprint and jump performances in highly trained young soccer players of different chronological age: Effects of linear VS. CHANGE-OF-DIRECTION sprint training.

J Exerc Sci Fit 2021 Apr 13;19(2):81-90. Epub 2020 Nov 13.

Univ Rennes, M2S (Laboratoire Mouvement, Sport, Santé) - EA 1274, F-35000, Rennes, France.

Objective: The aim of this study was to examine the effects of two different sprint-training regimes on sprint and jump performances according to age in elite young male soccer players over the course of one soccer season.

Methods: Players were randomly assigned to two training groups. Group 1 performed systematic change-of-direction sprints (CODST, U19 [n = 9], U17 [n = 9], U15 [n = 10]) while group 2 conducted systematic linear sprints (LST, U19 [n = 9], U17 [n = 9], U15 [n = 9]). Training volumes were similar between groups (40 sprints per week x 30 weeks = 1200 sprints per season). Pre and post training, all players performed tests for the assessment of linear and slalom sprint speed (5-m and 10-m), countermovement jump, and maximal aerobic speed performance.

Results: For all physical fitness measures, the baseline-adjusted means data (ANCOVA) across the age groups showed no significant differences between LST and CODST at post (0.061 < p < 0.995; 0.0017 < d < 1.01). The analyses of baseline-adjusted means for all physical fitness measures for U15, U17, and U19 (LST vs. CODST) revealed no significant differences between LST and CODST for U15 (0.213 < p < 0.917; 0.001 < d < 0.087), U17 (0.132 < p < 0.976; 0.001 < d < 0.310), and U19 (0.300 < p < 0.999; 0.001 < d < 0.049) at post.

Conclusions: The results from this study showed that both, LST and CODST induced significant changes in the sprint, lower limbs power, and aerobic performances in young elite soccer players. Since no significant differences were observed between LST and CODST, the observed changes are most likely due to training and/or maturation. Therefore, more research is needed to elucidate whether CODST, LST or a combination of both is beneficial for youth soccer athletes' performance development.
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http://dx.doi.org/10.1016/j.jesf.2020.10.003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7732877PMC
April 2021

L-Arginine Improves Endurance to High-Intensity Interval Exercises in Overweight Men.

Int J Sport Nutr Exerc Metab 2020 Dec 1;31(1):46-54. Epub 2020 Dec 1.

Université Rennes 2.

The effects of acute consumption of L-Arginine (L-Arg) in healthy young individuals are not clearly defined, and no studies on the effects of L-Arg in individuals with abnormal body mass index undertaking strenuous exercise exist. Thus, we examined whether supplementation with L-Arg diminishes cardiopulmonary exercise testing responses, such as ventilation (VE), VE/VCO2, oxygen uptake (VO2), and heart rate, in response to an acute session of high-intensity interval exercise (HIIE) in overweight men. A double-blind, randomized crossover design was used to study 30 overweight men (age, 26.5 ± 2.2 years; body weight, 88.2 ± 5.3 kilogram; body mass index, 28.0 ± 1.4 kg/m2). Participants first completed a ramped-treadmill exercise protocol to determine VO2max velocity (vVO2max), after which they participated in two sessions of HIIE. Participants were randomly assigned to receive either 6 g of L-Arg or placebo supplements. The HIIE treadmill running protocol consisted of 12 trials, including exercise at 100% of vVO2max for 1 min interspersed with recovery intervals of 40% of vVO2max for 2 min. Measurements of VO2 (ml·kg-1·min-1), VE (L/min), heart rate (beat per min), and VE/VCO2 were obtained. Supplementation with L-Arg significantly decreased all cardiorespiratory responses during HIIE (placebo+HIIE vs. L-Arg+HIIE for each measurement: VE [80.9 ± 4.3 L/min vs. 74.6 ± 3.5 L/min, p < .05, ES = 1.61], VE/VCO2 [26.4 ± 1.3 vs. 24.4 ± 1.0, p < .05, ES = 1.8], VO2 [26.4 ± 0.8 ml·kg-1·min-1 vs. 24.4 ± 0.9 ml·kg-1·min-1, p < .05, ES = 2.2], and heart rate [159.7 ± 6.3 beats/min vs. 155.0 ± 3.7 beats/min, p < .05, d = 0.89]). The authors conclude consuming L-Arg before HIIE can alleviate the excessive physiological strain resulting from HIIE and help to increase exercise tolerance in participants with a higher body mass index who may need to exercise on a regular basis for extended periods to improve their health.
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http://dx.doi.org/10.1123/ijsnem.2020-0054DOI Listing
December 2020

Testosterone Responses to Intensive, Prolonged Endurance Exercise in Women.

Endocrines 2020 Dec 5;1(2):119-124. Epub 2020 Nov 5.

Department of Exercise & Sport Science, University of North Carolina, Chapel Hill, NC 27599, USA.

Objective: To examine the response of testosterone in women to an intensive, prolonged endurance exercise bout that mimicked a competitive event.

Methods: Ten healthy eumenorrheic women ran to exhaustion at ~100% of their ventilatory threshold in their follicular menstrual cycle phase. Testosterone measures were assessed pre-exercise, immediately, 30 min, 60 min, 90 min, and 24 h post-exercise.

Results: At exhaustion (75.1 ± 7.0 min), total (56%), free (36%), and bioavailable testosterone (50%) were increased from pre-exercise values (< 0.05). At 24 h post-exercise, these measures were decreased from pre-exercise values (-21%, -31%, -18%, respectively; < 0.05). Effect sizes for these changes ranged from medium to large in magnitude.

Conclusion: Testosterone was elevated in the early recovery period following exhaustive endurance exercise but was reduced by 24 h afterward. These outcomes are comparable to responses seen in men when sex-based concentration differences are considered.
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http://dx.doi.org/10.3390/endocrines1020011DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7695234PMC
December 2020
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