Untrained Women Research Articles

Carbohydrate-Energy Replacement Following High-Intensity Interval Exercise Blunts Next-Day Glycemic Control in Untrained Women.

BackgroundImproved glycemic control has been reported for ∼24 h following low-volume high-intensity interval exercise (HIIE), but it is unclear if this is a direct effect of exercise or an indirect effect of the exercise-induced energy deficit. The purpose of this study was to investigate the effect of carbohydrate-energy replacement after low-volume HIIE on 24 h glycemic control in women.MethodsSeven untrained women (age: 22 ± 2 yr; BMI: 22 ± 3 kg/m2; VO2peak: 33 ± 7 ml/kg/min) completed three 2-day trials in the mid-follicular phase of the menstrual cycle. Continuous glucose monitoring was used to measure blood glucose concentrations during, and for 24 h following three conditions: (1) HIIE followed by a high-carbohydrate energy replacement drink (EX-HC); (2) HIIE followed by a non-caloric taste-matched placebo drink (EX-NC); and (3) seated control with no drink (CTL). HIIE involved an evening session (1,700 h) of 10 × 1-min cycling efforts at ∼90% maximal heart rate with 1 min recovery. Diet was standardized and identical across all three 2-day trials, apart from the post-exercise carbohydrate drink in EX-HC, which was designed to replenish the exercise-induced energy expenditure. Postprandial glycemic responses to the following days breakfast, snack, lunch, and dinner, as well as 24 h indices of glycemic control, were analyzed.ResultsThe day after HIIE, postprandial glycemia following breakfast and snack were reduced in EX-NC compared to EX-HC, as reflected by lower 3 h glucose mean (breakfast: 5.5 ± 0.5 vs. 6.7 ± 1, p = 0.01, Cohen’s d = 1.4; snack: 4.9 ± 0.3 vs. 5.7 ± 0.8 mmol/L, p = 0.02, d = 1.4) and/or area under the curve (AUC) (breakfast: 994 ± 86 vs. 1,208 ± 190 mmol/L x 3 h, p = 0.01, d = 1.5). Postprandial glycemic responses following lunch and dinner were not different across conditions (p > 0.05). The 24 h glucose mean (EX-NC: 5.2 ± 0.3 vs. EX-HC: 5.7 ± 0.7 mmol/L; p = 0.02, d = 1.1) and AUC (EX-NC: 7,448 ± 425 vs. EX-HC: 8,246 ± 957 mmol/L × 24 h; p = 0.02, d = 1.1) were reduced in EX-NC compared to EX-HC.ConclusionPost-exercise carbohydrate-energy replacement attenuates glycemic control the day following a single session of low-volume HIIE in women.

Moderate and Higher Protein Intakes Promote Superior Body Recomposition in Older Women Performing Resistance Training.

Resistance training (RT) combined with appropriate dietary intake can promote a concomitant increase in skeletal muscle mass (SMM) and reduction in fat mass, a condition termed body recomposition. This study's primary purpose was to explore the effects of protein ingestion on body recomposition after 24 wk of RT in older women. Data from 130 untrained older women (68.7 ± 5.6 yr, 66.5 ± 11.5 kg, 155.5 ± 6.0 cm, and 27.4 ± 4.0 kg·m-2) across six studies were retrospectively analyzed. The participants were divided into tertiles according to their customary protein intake (g·kg-1·d-1): lower (LP; n = 45), moderate (MP; n = 42), and higher (HP; n = 43) protein intake. Participants performed a whole-body RT program carried out over 24 wk (eight exercises, three sets, 8-15 repetitions, three sessions a week). SMM and fat mass were determined by dual-energy x-ray absorptiometry. All groups increased SMM from baseline (P < 0.05), with the HP and MP groups showing greater increases than the LP group (LP, 2.3%; MP, 5.4%; and HP, 5.1%; P < 0.05). Reductions in fat mass were similar for all three groups (LP, 1.7%; MP, 3.7%; and HP, 3.1%; P > 0.05). The composite z-score of the percentage changes from pretraining to posttraining indicated greater positive body recomposition values for HP and MP compared with LP (P < 0.05). Results suggest that protein intake is a moderating variable for body recomposition in older women undergoing RT, with a low protein intake having a less favorable effect on body recomposition.

Differential Autophagy Response in Men and Women After Muscle Damage.

Following muscle damage, autophagy is crucial for muscle regeneration. Hormones (e.g., testosterone, cortisol) regulate this process and sex differences in autophagic flux exist in the basal state. However, to date, no study has examined the effect of a transient hormonal response following eccentric exercise-induced muscle damage (EE) between untrained young men and women. Untrained men (n = 8, 22 ± 3 years) and women (n = 8, 19 ± 1 year) completed two sessions of 80 unilateral maximal eccentric knee extensions followed by either upper body resistance exercise (RE; designed to induce a hormonal response; EE + RE) or a time-matched rest period (20 min; EE + REST). Vastus lateralis biopsy samples were collected before (BL), and 12 h, and 24 h after RE/REST. Gene and protein expression levels of selective markers for autophagic initiation signaling, phagophore initiation, and elongation/sequestration were determined. Basal markers of autophagy were not different between sexes. For EE + RE, although initiation signaling (FOXO3) and autophagy-promoting (BECN1) genes were greater (p < 0.0001; 12.4-fold, p = 0.0010; 10.5-fold, respectively) for women than men, autophagic flux (LC3-II/LC3-I protein ratio) did not change for women and was lower (p < 0.0001 3.0-fold) than men. Furthermore, regardless of hormonal changes, LC3-I and LC3-II protein content decreased (p = 0.0090; 0.547-fold, p = 0.0410; 0.307-fold, respectively) for men suggesting increased LC3-I lipidation and autophagosome degradation whereas LC3-I protein content increased (p = 0.0360; 1.485-fold) for women suggesting decreased LC3-I lipidation. Collectively, our findings demonstrated basal autophagy was not different between men and women, did not change after EE alone, and was promoted with the acute hormonal increase after RE only in men but not in women. Thus, the autophagy response to moderate muscle damage is promoted by RE-induced hormonal changes in men only.

Estrogen modulates metabolic risk profile after resistance training in early postmenopausal women: a randomized controlled trial.

Women experience an unhealthy change in metabolic risk profile at menopause. The purpose of the present study was to determine effects of resistance training with or without transdermal estrogen therapy (ET) on adipose tissue mass and metabolic risk profile in early postmenopausal women. A double-blinded randomized controlled trial, where healthy, untrained postmenopausal women were allocated to supervised resistance training with placebo (PLC, n = 16) or transdermal ET (n = 15) for 12 weeks. Endpoints with prespecified hypotheses were the change in total fat mass (FM) (main endpoint) and the change in visceral FM (secondary endpoint) from before to after the intervention. Additionally, prespecified endpoints of body composition, metabolic health-related blood markers, fat%, fat cell size, and lipogenic markers in subcutaneous adipose tissue (SAT) from abdominal and femoral region were explored. Compared with the ET group, the PLC group experienced a greater reduction (time × treatment interaction P < 0.05) in total FM (PLC vs ET: -5.6% vs -1.1%) and visceral FM (-18.6% vs -6.8%), and femoral SAT (-5.6% vs 1.0%), but not abdominal SAT mass (-8.5% vs -2.8%, P = 0.15).The ET group improved their metabolic blood profile by reduced low-density lipoprotein, glucose and hemoglobin A1c compared with PLC (time × treatment interaction P < 0.05). The intervention induced changes in lipolytic markers of abdominal SAT, whereas no changes were detected in femoral SAT. Use of transdermal ET reduced adipose tissue loss, but improved metabolic blood markers when combined with 12 weeks of progressive resistance training in early postmenopausal women.

Blood Pressure and Heart Rate Variability Responses to High-intensity Interval Training in Untrained Postmenopausal Women

ABSTRACT Purpose: The aim of this study was to analyze the blood pressure (BP) and heart rate variability (HRV) responses in untrained postmenopausal women submitted to acute single sessions of high-intensity interval training (HIT). Method: Sixteen postmenopausal women (59.9 ± 5.6 years, 26.7 ± 3.0 kg/m2) participated in a random order of two acute sessions in a balanced crossover format: control without exercise in sitting position or HIT session. BP and heart rate (HR) were recorded before and during 60 min following the sessions. Results: Diastolic (DBP), mean BP (MBP), and double product (DPO) showed interaction (p < .01). DBP, MBP, and DPO increased (p < .01) after HIT but not after the control session. The area under the curve (AUC) of DBP (p = .02) and DPO (p < .01) were different between conditions. Time and frequency indices of HRV presented interaction (p < .05) which impaired these indices post-HIT, but not post-control. The AUC of time and frequency HRV indices were different between conditions. Conclusions: A single session of HIT may increase BP and cardiac stress and cause perturbation of the autonomic function in untrained postmenopausal women.

Photobiomodulation Therapy at 808 nm Does Not Improve Biceps Brachii Performance to Exhaustion and Delayed-Onset Muscle Soreness in Young Adult Women: A Randomized, Controlled, Crossover Trial.

ObjectiveThis study aims to investigate the effects of laser photobiomodulation (PBM) at 808 nm on biceps brachii performance to exhaustion, rating of perceived exertion (RPE), and delayed onset muscle soreness (DOMS) in untrained young women.MethodsThirteen young women (20.1 ± 2.9 years) participated in a crossover study in which they received, in a counterbalanced manner, active and placebo laser PBM on two occasions (T1 and T2), separated by a 7-day washout period. During T1 and T2, participants received active (100 mW output power, irradiance of 35.7 W cm–2, and total energy of 28 J/arm) or placebo laser irradiation on the biceps brachii muscle at 20 min before the repetitions-to-failure test [six sets at 60% of one-repetition maximum (1RM) until failure] for elbow flexion exercise. The number of repetitions performed and RPE over the six sets, as well as DOMS from basal up to 72 h after the repetitions-to-failure test, were recorded.ResultsThere was a significant (time, p < 0.05) reduction in the number of repetitions performed and an increase in RPE over six sets, with no statistical differences between placebo and active laser conditions (treatment × time, p > 0.05). DOMS increased at 24 h postexercise and progressively returned to baseline after 72 h in both conditions (time, p < 0.05; treatment × time, p > 0.05).ConclusionOur results indicate that acute laser PBM at 808 nm does not improve biceps brachii performance to exhaustion, RPE, and DOMS in untrained women.

Hormonal stress responses of growth hormone and insulin-like growth factor-I in highly resistance trained women and men

The purpose of this study was to examine the responses of growth hormone (GH) and insulin-like growth factor-I (IGFI) to intense heavy resistance exercise in highly trained men and women to determine what sex-dependent responses may exist. Subjects were highly resistance trained men (N = 8, Mean ± SD; age, yrs., 21 ± 1, height, cm, 175.3 ± 6.7, body mass, kg, 87.0 ± 18.5, % body fat, 15.2 ± 5.4, squat X body mass, 2.1 ± 0.4; and women (N = 7; Mean ± SD, age, yrs. 24 ± 5, height, cm 164.6 ± 6.7, body mass, kg 76.4 ± 8.8, % body fat, 26.9 ± 5.3, squat X body mass, 1.7 ± 0.6). An acute resistance exercise test protocol (ARET) consisted of 6 sets of 10 repetitions at 80% of the 1 RM with 2 min rest between sets was used as the stressor. Blood samples were obtained pre-exercise, after 3 sets, and then immediately after exercise (IP), 5, 15, 30, and 70 min post-exercise for determination of blood lactate (HLa), and plasma glucose, insulin, cortisol, and GH. Determination of plasma concentrations of IGFI, IGF binding proteins 1, 2, and 3 along with molecular weight isoform factions were determined at pre, IP and 70 min. GH significantly (P ≤ 0.05) increased at all time points with resting concentrations significantly higher in women. Significant increases were observed for HLa, glucose, insulin, and cortisol with exercise and into recovery with no sex-dependent observations. Women showed IGF-I values that were higher than men at all times points with both seeing exercise increases. IGFBP-1 and 2 showed increase with exercise with no sex-dependent differences. IGFBP-3 concentrations were higher in women at all-time points with no exercise induced changes. Both women and men saw an exercise induced increase with significantly higher values in GH in only the mid-range (30-60 kD) isoform. Only women saw an exercise induced increase with significantly higher values for IGF fractions only in the mid-range (30–60 kD) isoform, which were significantly greater than the men at the IP and 70 min post-exercise time points. In conclusion, the salient findings of this investigation were that in highly resistance trained men and women, sexual dimorphisms exist but appear different from our prior work in untrained men and women and appear to support a sexual dimorphism related to compensatory aspects in women for anabolic mediating mechanisms in cellular interactions.

Partial range of motion training elicits favorable improvements in muscular adaptations when carried out at long muscle lengths

ABSTRACT The study compared changes in strength and regional muscle hypertrophy between different ranges of motion (ROM) in the knee extension exercise. Forty-five untrained women were randomized to either a control group or to perform the exercise in one of the following 4 groups (0°=extended knee): Full ROM (FULLROM: 100°−30° of knee flexion); Initial Partial ROM (INITIALROM: 100°−65°); Final Partial ROM (FINALROM: 65°−30°); Varied ROM (VARROM: daily alternation between the ROM of INITIALROM and FINALROM). Pre- and post-training assessments included one repetition maximum (1RM) testing in the ROM corresponding to the initial, final and full ROM, and measurement of cross-sectional areas of the rectus femoris and vastus lateralis muscles at 40%, 50%, 60% and 70% of femur length in regard to regional muscle hypertrophy. Results showed that the INITIALROM group presented a greater relative increase than all groups at 70%, and at 50% and 60% the increases were greater than FINALROM, FULLROM, and non-training control (CON) groups. Moreover, FINALROM group presented similar changes compared to the CON group at 60% and 70%. In regard to 1RM, FINALROM and INITIALROM groups presented greater relative increases at the ROM trained, and no group showed greater increases than VARROM or INITIALROM, regardless the ROM tested. In conclusion, partial ROM training in the initial phase of the knee extension exercise promoted greater relative hypertrophy in certain muscle regions than training in other ROM configurations, and no group promoted a greater 1RM increase than VARROM group, which showed similar 1RM increases in the different ROMs tested.

A prolonged hiatus in postmenopausal HRT, does not nullify the therapy's positive impact on ageing related sarcopenia.

BackgroundPrevious work suggest a positive skeletal muscle effect of hormone replacement therapy (HRT) on skeletal muscle characteristics This study aimed to quantify any continued positive effect of HRT even after a sustained hiatus in treatment, controlling for two key muscle modulation hormones: Estradiol (E2) and Tri-iodo-thyronine (T3).Method and findingsIn 61 untrained women (18-78yrs) stratified as pre-menopausal, post-menopausal without (No_HRT) and post-menopausal with (Used_HRT) HRT history, body composition, physical activity, serum E2 and T3 were assessed by dual energy x-ray absorptiometry, Baecke questionnaire and ELISA. Gastrocnemius medialis (GM) and tibialis anterior (TA) electromyographic profiles (mean power frequency (mPowerF)), isometric plantar-flexion (PF) and dorsi-flexion (DF) maximum voluntary contraction (MVC), rate of torque development (RTD), isokinetic MVC and muscle volume, were assessed using surface electromyography, dynamometry and ultrasonography. Muscle quality was quantified as MVC per unit muscle size. E2 and E2:T3 ratio were significantly lower in postmenopausal participants, and were positively correlated with RTD even after controlling for adiposity and/or age. Pre-menopausal females had greater MVC in 8/8 PF and 2/5 DF (23.7–98.1%; P<0.001–0.049) strength measures compared to No_HRT, but only 6/8 PF (17.4–42.3%; P<0.001–0.046) strength measures compared to Used_HRT. Notably, Used_HRT had significant higher MVC in 7 PF MVC (30.0%-37.7%; P = 0.006–0.031) measures than No_HRT, while premenopausal and Used_HRT had similar uncorrected muscle size or quality. In addition, this cross-sectional data suggest an annual reduction in GM muscle volume corrected for intra-muscular fat by 1.3% in No_HRT and only 0.5% in Used_HRT.ConclusionEven years after cessation of the therapy, a history of HRT is positively associated with negating the expected post-menopausal drop in muscle quantity and quality. Whilst mPowerF did not differ between groups, our work highlights positive associations between RTD against E2 and E2:T3. Notwithstanding our study limitation of single time point for blood sampling, our work is the first to illustrate an HRT attenuation of ageing-related decline in RTD. We infer from these data that high E2, even in the absence of high T3, may help maintain muscle contractile speed and quality. Thus our work is the first to points to markedly larger physiological reserves in women with a past history of HRT.

Effects of the Small-Sided Soccer Games on Blood Pressure in Untrained Hypertensive Adults: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

This systematic review with meta-analysis was conducted to assess the effects of small-sided games (SSGs)-based programs on the systolic and diastolic blood pressure of untrained hypertensive adults. The data sources utilized were Web of Science, Scopus, SPORTDiscus, and PubMed. The eligibility criteria were: (i) randomized controlled trials including a control group and an intervention group exclusively using soccer SSGs; (ii) intervention and control groups including an untrained hypertensive adult population; (iii) articles written in English; and (iv) only full-text and original articles. The database search initially identified 241 titles. From those, five articles were eligible for the systematic review and meta-analysis. The included randomized controlled studies involved five individual experimental groups and 88 participants, and 68 participants in the five control groups. The results showed a large and beneficial effect of SSG on systolic (ES = 1.69; 95% CI = 0.71 to 2.66; p = 0.001; I2 = 85.2%; Egger’s test p = 0.101) and diastolic blood pressure (ES = 2.25; 95% CI = 1.44 to 3.06; p < 0.001; I2 = 74.8%; Egger’s test p = 0.118) when compared to the control groups. The findings of the current systematic review and meta-analysis revealed consistent beneficial effects of recreational soccer SSGs on untrained men and women from the hypertensive population, although high levels of heterogeneity.

English

Introduction: The adherence on endurance running events is increasing exponentially around the World in both previously untrained men and women, thus the incorporation of more appropriate and individualized training approaches are required. It is not known if male and female untrained runners differ in the responses to endurance running training on performancerelated variables. Objective: We aimed to compare performance-related responses to an endurance running training program between untrained men and women. Material and method: Sixteen participants (8 men and 8 women) were paired in the baseline by age, body mass index, and percentage in which time to complete 5 km (t5km) represented from the average of best 50 runners t5km in the greatest regional race for each gender. They completed an 11-week training protocol alternating high-intensity interval training and moderateintensity continuous running, three times per week, in a running track. In the week 1 and 11 of the protocol (baseline and post-training weeks), peak running velocity at treadmill (Vpeak), time limit (tlim) at 100% Vpeak, t5km, and the index rMSSD of heart rate variability (HRV) were measured for cardiac autonomic function. Baseline gender-differences were accounted in the analysis. Results: Male and female significantly improved Vpeak (9.4 ± 1.7% and 7.2 ± 1.7%, respectively) and t5km (-13.0 ± 1.8% for both), and no gender-related differences for the adaptations in these two variables were observed. The tlim at 100% Vpeak and rMSSD did not change across the training period in both groups. Percentage of change for men was “moderately” higher than for women for rMSSD (33.4 ± 40.7% vs. 13.9 ± 21.4%), although statistically non-significant. Conclusion: Men and women responses to training were similar with regards to their running performance and cardiac autonomic function. With regards to practical application, Vpeak and its tlim can be applied in exercise settings for the prescription of moderate- to high-intensity running training with similar benefits regardless of the biological gender

Effect of Resistance Exercise with Blood Flow Restriction on Peripheral Oxygen Saturation and Cardiovascular Stress in Untrained Diabetic Women: A Cross and Randomized Study

This study aimed to analyze the effects of high-load (HL) resistance exercise (RE), low-load (LL) RE, and LL RE with blood flow restriction (LL + BFR) in peripheral oxygen saturation level (SpO2), heart rate (HR), and double product (DP: HR × systolic blood pressure [SBP]) in untrained women with type 2 diabetes (T2DM). Ten untrained women with T2DM (Age = 56.9 ± 7.4 years; BMI = 27.2 ± 4.2 kg/m2; and Diagnostic time = 10.6 ± 4.1 years) participated in this study. Participants attended a local gym for four non-consecutive days. During the first visit, arterial occlusion pressure (AOP) and predictive values of one maximum repetition (1RM) for knee extension exercise (KE) were assessed. The second, third, and fourth visits were randomly assigned to the following: HL RE (~65% of predicted 1RM in 3 sets of 10 repetitions), LL RE (~20% of predicted 1RM in 3 sets of 15 repetitions), and LL + BFR RE (~20% of predicted 1RM in 3 sets of 15 repetitions; 50% of AOP). HR, SBP e SpO2 were assessed before and immediately after each protocol. All protocols significantly increased the analyzed variables (p ≤ 0.05). There were no significant differences in hemodynamic responses between the protocols (p > 0.05). Therefore, resistance exercise with BFR seems to promote cardiovascular responses similar to traditional low and high load resistance exercise protocols in untrained diabetic women. Keywords: Double Product, Heart Rate, Ischemia, Hemodynamics, Kaatsu training, Resistance Training, Therapeutic Occlusion. Read more →

Can training close the gender wage gap? Evidence from Vietnamese SMEs

ABSTRACT Firm-provided training is generally seen as an important tool for bridging the skills gap between the labour force and what the private sector demands. Little is known about how successful such training can be in closing the gender wage gap. We use a matched employer-employee panel dataset to assess why firms train and whether formal training affects wage outcomes in Vietnamese SMEs. Training is generally found to be firm-sponsored and specific in nature. We find that training is associated with higher wages for trained women as compared to both untrained women and men. However, we do not find a statistically significant wage difference between trained women and men. Furthermore, the wage increase is only associated with on-the-job training. Our findings indicate that, at least in Vietnam, firm-sponsored on-the-job training could help increase women’s labour productivity and thus contribute to closing the gender wage gap.

Sex Dimorphism in Muscle Damage-induced Inflammation.

The purpose of this study was to determine the effect of resistance exercise (RE)-induced hormonal changes on intramuscular cytokine gene expression after muscle damage in untrained men and women. Men (n = 8, 22 ± 3 yr) and women (n = 8, 19 ± 1 yr) completed two sessions of 80 unilateral maximal eccentric knee extensions followed by either an upper body RE bout (EX) or a time-matched period (CON). Muscle samples (vastus laterals) were analyzed for mRNA expression of interleukin (IL) 6, IL-10, IL-15, TNFA, TGFB, CCL2, and CD68 at PRE, 12 h, and 24 h after the session. A significant time-sex-condition interaction was found for TGFB with an increase for EX in men at 12 h from PRE. For EX, TGFB was also greater in men than in women at 12 and 24 h. Significant time-sex and condition-sex interactions were found for IL-10 with an increase for men that was greater than for women at 12 and 24 h. IL-10 was lower in EX than CON for men. A significant time-sex interaction was found for TNFA with an increase for men that was greater than for women at 24 h. A significant time-condition interaction was found for CD68 with an increase at 12 h and decrease at 24 h for EX and CON. CD68 was lower in EX than CON at 12 h. A significant time effect was found for IL6 and CCL2 with an increase at 12 and 24 h. Results suggest that women seem to have a muted intramuscular cytokine (i.e., IL-10, TNF-α, and TGF-β) response to muscle damage compared with men.

Effect of a 7-week low intensity synchronous handcycling training programme on physical capacity in abled-bodied women

ABSTRACT This study evaluated the effect of a low-intensity norm duration synchronous handcycle wheelchair training in untrained able-bodied women. The training group (n = 9) received 7-weeks of low-intensity upper body training in an instrumented handcycle on a motor-driven treadmill (MDT), 3 × 30 min/week at 30% heart rate reserve. The control group (n = 10) received no training. Incremental handcycle tests on the MDT were used to determine peak values for oxygen uptake (VO2peak), power output (POpeak), heart rate (HRpeak), minute ventilation (VEpeak), and respiratory exchange ratio (RERpeak), submaximal values for heart rate (HR), oxygen uptake (VO2) and gross efficiency (GE) before and after training. Local perceived discomfort and rate of perceived exertion (RPE) were also assessed. Training significantly improved POpeak (+20%), HRpeak (+3%), RERpeak (+5%), submaximal GE (+21%), VO2 (−20%), VE (−33%), HR (−12%) and RPE was low (7.1 ± 0.5) (p < 0.05). No effects were found in VO2peak and VEpeak (p > 0.05). Though VO2peak did not improve, low-intensity norm duration handcycling training improved handcycling POpeak, while RPE was low. Also, GE increased, suggesting a motor control improvement. Handcycle training seems to be an appropriate exercise mode to improve physical capacity, and prevent early fatigue and overuse in untrained individuals.

Blood Glucose Response to Unilateral and Bilateral Resistance Training Among Trained Women

Exercise selection is one of the crucial factors in designing a comprehensive training program. The exposure of different exercise selection may stimulate the specific adaptation imposed demand. In the construction of any resistance training (RT) program, it is important to choose whether to apply bilaterally (BI) or unilaterally (UNI) exercise. The present study aimed to look into the physiological responses of blood glucose (BG) between UNI and BI RT. The quantitative research method was used, RT (UNI versus BI training) as the independent variables whereas BG set as the dependent variable. In order to measure training effects following a single bout of different training intervention (UNI versus BI), a crossover experimental pre and post-test design were implemented. A total of sixteen (n = 16) trained women with a mean age of 23 (SD = 1.35) years old went through a single bout of RT involved a total body exercise using major muscles group with 80% of 1RM for each protocol (UNI and BI) for 10 repetitions to maximal effort (for 3 sets). Crossover design would be more accurate in exposing different training protocol to a similar characteristic of individuals as compared using different individuals. The results revealed that blood glucose (BG) was statistically changed (p &lt; .001) across times, and finding shows there is no difference between training protocols (p = .39). Based on the results, it would be interesting to observe the blood glucose and/or energy metabolism between UNI versus BI RT during exercise as well as to investigate the relationship between BG and calories expenditure during exercises. Future research on UNI versus BI RT could venture onto other populations such as the untrained women, men population, elderly and specific population such as diabetic population in order to further understand the physiology of human body responded towards exercise. Other types of hormones analysis including insulin, growth hormone, and cortisol can be included. Besides, future research should consider a long run study that involves chronic adaptation of RT on the human body in order to prevent and alleviate disease.

Parasympathetic modulation during sleep time is reduced after maximal exercise, correlated with aerobic fitness in young women

abstract It is known that cardiovascular risk is increased during exercise and recovery. Thus, it is necessary to assess all the risk associated with exercise to minimize the possibility of cardiovascular events. The aim of this study was to verify whether a maximal exercise alters ambulatory cardiac autonomic modulation in untrained women and whether aerobic fitness is correlated to cardiac autonomic modulation. Twelve women (25.35 ± 5.44 years) were outfitted with the Holter monitor on an experimental (after maximum exercise) and a control day to heart rate variability (HRV) evaluation. Maximal exercise increased 24 h heart rate (82 ± 14 vs 77 ± 11 bpm; p = 0.04) and during sleep time (72 ± 14 vs. 65 ± 9 bpm; p = 0.01), reduced parasympathetic modulation (HF – n.u. 49.96 ± 11.56 vs 42.10 ± 14.98; p = 0.04), and increased low-frequency/high-frequency ratio (2.88 ± 3.24 vs 1.31 ± 0.60; p = 0.03) during sleep time compared to the control day. Aerobic fitness was correlated positively with LF, HF, and HF (n.u.) indices (r = 0.61 to 0.73, p &lt; 0.05) and correlated negatively with LF (n.u.) and LF/HF ratio (Rho = - 0.57 to - 0.69; p &lt; 0.05). Maximal exercise alters parasympathetic modulation during sleep time in untrained women. Ambulatory cardiac autonomic modulation after exercise is related to aerobic fitness.

High-Fat Ketogenic Diets and Physical Performance: A Systematic Review

Use of high-fat, ketogenic diets (KDs) to support physical performance has grown in popularity over recent years. While these diets enhance fat and reduce carbohydrate oxidation during exercise, the impact of a KD on physical performance remains controversial. The objective of this work was to assess the effect of KDs on physical performance compared with mixed macronutrient diets [control (CON)]. A systematic review of the literature was conducted using PubMed and Cochrane Library databases. Randomized and nonrandomized studies were included if participants were healthy (free of chronic disease), nonobese [BMI (kg/m2) <30], trained or untrained men or women consuming KD (<50 g carbohydrate/d or serum or whole-blood β-hydroxybutyrate >0.5 mmol/L) compared with CON (fat, 12-38% of total energy intake) diets for ≥14 d, followed by a physical performance test. Seventeen studies (10 parallel, 7 crossover) with 29 performance (13 endurance, 16 power or strength) outcomes were identified. Of the 13 endurance-type performance outcomes, 3 (1 time trial, 2 time-to-exhaustion) reported lower and 10 (4 time trials, 6 time-to-exhaustion) reported no difference in performance between the KD compared with CON. Of the 16 power or strength performance outcomes, 3 (1 power, 2 strength) reported lower, 11 (4 power, 7 strength) no difference, and 2 (power) enhanced performance in the KD compared with the CON. Risk of bias identified some concern of bias primarily due to studies allowing participants to self-select diet intervention groups and the inability to blind participants to the study intervention. Overall, the majority of null results across studies suggest that a KD does not have a positive or negative impact on physical performance compared with a CON diet. However, discordant results between studies may be due to multiple factors, such as the duration consuming study diets, training status, performance test, and sex differences, which will be discussed in this systematic review.

Effects of a 16-week recreational team handball intervention on aerobic performance and cardiometabolic fitness markers in postmenopausal women: A randomized controlled trial

BackgroundPostmenopausal women have an elevated risk of developing cardiovascular diseases, which can be counteracted by conventional exercise regimes or recreational football. Less is known about the impact of exercise programmes based on other team sports. Thus, we examined the effects of recreational team handball on aerobic performance, cardiorespiratory fitness and cardiometabolic health in untrained postmenopausal women. MethodsSixty-seven participants (age 68 ± 6 years, stature 157 ± 6 cm, body mass 67 ± 10 kg, fat mass 37 ± 7%, VO2peak 25.2 ± 3.6 mL/min/kg, Yo-Yo intermittent endurance level 1 test performance (YYIE1) 230 ± 103 m) with no previous experience of team handball were randomly allocated to either a team handball (THG, n = 41) or a control (CG, n = 26) group. THG performed 2–3 60-min training sessions per week for 16 weeks. YYIE1 performance and cardiometabolic markers were evaluated at baseline and post-intervention. ResultsAverage attendance during recreational team handball training was 1.9 ± 0.4 sessions per week, with mean heart rates of 76 ± 6%HRmax and 18 ± 9 min (44 ± 20% of total time) played at HR > 80%HRmax. A between-group effect was observed for YYIE1 performance, with a more pronounced improvement in aerobic exercise performance in THG compared to CG (70 ± 62 vs 15 ± 44%; p < 0.001). Within-group improvements (p < 0.05) were observed for THG with regard to VO2peak (7 ± 10%), incremental treadmill test time to exhaustion (TTE) (11 ± 14%), total cholesterol (−3 ± 9%) and low-density lipoprotein cholesterol (−2 ± 14%), with no significant changes in CG except an increase (p < 0.05) in TTE. Post-intervention values were higher for THG vs CG for YYIE1 performance (88%; 406 ± 216 vs 216 ± 75 m) and VO2peak (10%; 27.5 ± 3.8 vs 24.9 ± 3.6 mL/min/kg). ConclusionsRecreational team handball can be used to obtain moderate-to-vigorous aerobic intensities, and just 2 weekly 60-min team handball training sessions for 16 weeks can result in improvements in aerobic performance and in markers of cardiorespiratory fitness in postmenopausal women with no previous experience of the sport.

Molecular markers of skeletal muscle hypertrophy following 10 wk of resistance training in oral contraceptive users and nonusers.

The objective was to determine whether skeletal muscle molecular markers and SC number were influenced differently in users and nonusers of oral contraceptives (OCs) following 10 wk of resistance training. Thirty-eight young healthy untrained users (n = 20) and nonusers of OC (n = 18) completed a 10-wk supervised progressive resistance training program. Before and after the intervention, a muscle tissue sample was obtained from the vastus lateralis muscle for analysis of muscle fiber cross-sectional area (fCSA) and satellite cell (SC) and myonuclei number using immunohistochemistry, gene expression using PCR, protein expression, and myosin heavy chain composition. Following the training period, quadriceps fCSA (P < 0.05), SCs/type I fiber (P = 0.05), and MURF-1 mRNA (P < 0.01) were significantly increased with no difference between the groups. However, SCs/total fiber and SCs/type II fiber increased in OC users only, and SCs/type II fCSA tended (P = 0.055) to be greater in the OC users. Furthermore, in OC users there were a fiber type shift from myosin heavy chain (MHC) IIx to MHC IIa (P < 0.01), and expression of muscle regulatory factor 4 (MRF4) mRNA (P < 0.001) was significantly greater than in non-OC users. Use of second-generation OCs in young untrained women increased skeletal muscle MRF4 expression and SC number following 10 wk of resistance training compared with nonusers.NEW & NOTEWORTHY The effect of oral contraceptive use on the skeletal muscle regulatory pathways in response to resistance training has not been investigated previously. Here we present novel data, demonstrating that use of second-generation oral contraceptives in young untrained women increased skeletal muscle regulatory factor 4 expression and satellite cell number following 10 wk of resistance training compared with nonusers.