Healthy Active Males Research Articles

The Effect of Pre-Exercise Caffeine and Glucose Ingestion on Endurance Capacity in Hypoxia: A Double-Blind Crossover Trial.

The impact of caffeine and glucose supplementation in a hypoxic environment on endurance exercise performance remains inconclusive. The current study examined the effect of pre-exercise carbohydrate and caffeine supplementation on endurance exercise performance in an acute hypoxic environment. Eight healthy active young males participated in this double-blind, within-subjects crossover study. Participants ingested the test drink 60 min before exercising at 50% Wmax for 90 min on a cycle ergometer (fatiguing preload); there followed an endurance performance test at 85% Wmax until exhaustion in a hypoxic chamber (~15%O2). Participants completed four experimental trials in a randomized order: caffeine (6 mg·kg-1; Caff), glucose (1 g·kg-1; CHO), caffeine (6 mg·kg-1) + glucose (1 g·kg-1; Caff-CHO), and taste- and color-matched placebo with no caffeine or CHO (PLA). Blood samples were collected during fasting, pre-exercise, every 30 min throughout the exercise, and immediately after exhaustion. The caffeine and glucose trials significantly enhanced endurance capacity in hypoxic conditions by Caff, 44% (68.8-31.5%, 95% confidence interval), CHO, 31% (44.7-15.6%), and Caff-CHO, 46% (79.1-13.2%). Plasma-free fatty-acid and glycerol concentrations were higher in Caff and PLA than in CHO and Caff-CHO (p < 0.05). The estimated rate of fat oxidation was higher in Caff and PLA than in CHO and Caff-CHO (p < 0.05). There were no significant differences in ratings of perceived exertion between trials. In conclusion, the ingestion of caffeine, glucose, or caffeine + glucose one hour before exercising in hypoxic conditions significantly improved 85% Wmax endurance performance after prolonged exercise.

Crocus Sativus Linnaeus (Saffron) intake does not affect physiological and perceptual responses during a repeated sprint test in healthy active young males

The study aimed to investigate the effects of acute ingestion of saffron (SAF) on physiological (i.e., heart rate and blood lactate) and perceptual (i.e., ratings of perceived exertion [RPE] and feeling scale) measures in response to a repeated-sprint ability test (RSS) in healthy young males (N = 22; mean ± SD: age, 21.7 ± 1.24 yrs.). All participants completed two experimental trials with a one-week washout period using a double-blind, placebo-controlled, crossover design. In each session, the participants were randomly chosen to receive either a capsule of saffron (300 mg) (SAF session) or a capsule of lactose (PLB session) two hours before performing the RSS.No significant differences (p > 0.05) were found for heart rate, RPE, and feeling scale between the SAF or PLB sessions at pre- and post-RSS. There were no significant changes (p > 0.05) in peak time, total time, fatigue index, and blood lactate in either the SAF or PLB sessions. Acute SAF ingestion did not significantly improve RSS performance nor physiological and perceptual measures in active young males. Future trials should address the topic by using shortened/prolonged higher doses of SAF on biological, physical, physiological, and perceptual responses to acute and chronic exercise.

Effects of an Acute Dose of Zinc Monomethionine Asparate and Magnesium Asparate (ZMA) on Subsequent Sleep and Next-Day Morning Performance (Countermovement Jumps, Repeated Sprints and Stroop Test).

The goal of the present study was to determine whether an acute dose of a zinc-containing nutritional supplement (ZMA) has any effects on sleep and morning performance in recreationally trained males. Nineteen males participated in a repeated-measures within-subjects study to assess objective and subjective measures of sleep, completed counter-movement jumps (CMJ) and repeated sprint morning performance (RSP). Three days of baseline food intake showed no major deficiencies of zinc, magnesium or vitamin B6 for all participants (11.9 ± 3.4, 395 ± 103 and 2.7 ± 0.9 mg.day-1, respectively). Sleep (22:30-06:30 h) was assessed via actimetry, and either a control (no tablets, NoPill), dextrose placebo (PLAC) or ZMA was ingested 30-60 min before retiring to bed for two nights. The participants undertook the three conditions (NoPill, PLAC or ZMA) administered in a counterbalanced order. The data were analyzed using general linear models with repeated measures. In healthy active males who consume diets of adequate micronutrients, sleep normally and maintain good sleep hygiene (time to bed and wake times), ZMA supplementation had no beneficial effect on RSP or performance in the Stroop test (p > 0.05) but did improve CMJ height (p < 0.001) compared to that of PLAC but not NoPill (p > 0.05). Supplementation of ZMA for two nights had no effect on sleep, RSP or cognitive function. The NoPill condition elucidated the effects of the intervention under investigation.

Estimating the Total and Regional Body Fat of Physically Active Men Is Not Appropriate for Sedentary Men

Objectives. The reliability of predictive body fat equations remains unclear due to their inappropriate use across different subject cohorts and conditions. The objective of this study was to validate and cross-validate equations to predict total and regional body fat in young physically active males. Material and methods. Three hundred and five young male participants were divided into the following groups: active validation (n=165), active cross-validation (n=70), or sedentary cross-validation ones (n=70). The study used a stratified random sampling based on weekly physical activity level. The total and regional body fat mass were measured using dual-energy X-ray absorptiometry (DEXA) after an overnight fast. Simultaneous measurements of height, body mass, skinfold thickness, body mass index, and body circumferences were taken. The total and regional body fat predictive equations were generated using multiple linear stepwise regression models. The coefficient of determination (R²) and standard error of estimation (SEE) were calculated to examine the accuracy of the predictive equations. Furthermore, cross-validation groups were analysed. Results. The percentage of total body fat, trunk fat, legs fat, arms fat, and body mass index of active cross-validation were found to be significantly lower than in the sedentary cross-validation groups. The total body fat percentage was highly associated with abdominal skinfold thickness (R=0.68-0.74, P&lt;0.001), body mass index (R=0.55, P&lt;0.001), and suprailiac skinfold thickness (R=0.67-0.71, P&lt;0.001) in the active validation group. The predictive total and regional body fat equations of physically active men showed adjusted R² values ranging from 0.35 to 0.66, with standard error of estimation values between 2.74 to 4.35%. The standard error of estimation for the predictive percentage of total and regional body fat in the active cross-validation group was lower than in the sedentary cross-validation group. Conclusions. The findings demonstrate that new predictive total and regional body fat equations can be used to accurately estimate body fat in healthy young active males under fast conditions.

Betaine supplementation modulates betaine concentration by methylenetetrahydrofolate reductase genotype, but has no effect on amino acid profile in healthy active males: A randomized placebo-controlled cross-over study

Betaine supplementation is used by athletes, but its mechanism of action is still not fully understood. We hypothesized that betaine supplementation would increase betaine concentration and alter amino acid profiles in relation to MTHFR genotype and dose in physically active males. The study followed a randomized placebo-controlled cross-over design. Blood samples were collected before and after each supplementation period. Serum was analyzed for amino acid profile, homocysteine, betaine, choline, and trimethylamine N-oxide (TMAO) concentrations. For the washout analysis, only participants starting with betaine were included (n = 20). Statistical analysis revealed no differences in the amino acid profile after betaine supplementation. However, betaine concentration significantly increased after betaine supplementation (from 4.89 ± 1.59 µg/mL to 17.31 ± 9.21 µg/mL, P < .001), with a greater increase observed in MTHFR (C677T, rs180113) T-allele carriers compared to CC (P = .027). Betaine supplementation caused a decrease in homocysteine concentration (from 17.04 ± 4.13 µmol/L to 15.44 ± 3.48 µmol/L, P = .00005) and a non-significant increase in TMAO concentrations (from 0.27 ± 0.20 µg/ml to 0.44 ± 0.70 µg/ml, P = .053), but had no effect on choline concentrations. Serum betaine concentrations were not significantly different after the 21-day washout from the baseline values (baseline: 4.93 ± 1.87 µg/mL and after washout: 4.70 ± 1.70 µg/mL, P = 1.000). In conclusion, betaine supplementation increased betaine and decreased homocysteine concentrations, but did not affect the amino acid profile or choline concentrations in healthy active males. Betaine concentrations may be dependent on MTHFR genotype.

Supraspinal, spinal, and motor unit adjustments to fatiguing isometric contractions of the knee extensors at low and high submaximal intensities in males.

Contraction intensity is a key factor determining the development of muscle fatigue, and it has been shown to induce distinct changes along the motor pathway. The role of cortical and spinal inputs that regulate motor unit (MU) behavior during fatiguing contractions is poorly understood. We studied the cortical, spinal, and neuromuscular response to sustained fatiguing isometric tasks performed at 20% and 70% of the maximum isometric voluntary contraction (MVC), together with MU behavior of knee extensors in healthy active males. Neuromuscular function was assessed before and after performance of both tasks. Cortical and spinal responses during exercise were measured via stimulation of the motor cortex and spinal cord. High-density electromyography was used to record individual MUs from the vastus lateralis (VL). Exercise at 70%MVC induced greater decline in MVC (P = 0.023) and potentiated twitch force compared with 20%MVC (P < 0.001), with no difference in voluntary activation (P = 0.514). Throughout exercise, corticospinal responses were greater during the 20%MVC task (P < 0.001), and spinal responses increased over time in both tasks (P ≤ 0.042). MU discharge rate increased similarly after both tasks (P ≤ 0.043), whereas recruitment and derecruitment thresholds were unaffected (P ≥ 0.295). These results suggest that increased excitability of cortical and spinal inputs might be responsible for the increase in MU discharge rate. The increase in evoked responses together with the higher MU discharge rate might be required to compensate for peripheral adjustments to sustain fatiguing contractions at different intensities.NEW & NOTEWORTHY Changes in central nervous system and muscle function occur in response to fatiguing exercise and are specific to exercise intensity. This study measured corticospinal, neuromuscular, and motor unit behavior to fatiguing isometric tasks performed at different intensities. Both tasks increased corticospinal excitability and motor unit discharge rate. Our findings suggest that these acute adjustments are required to compensate for the exercise-induced decrements in neuromuscular function caused by fatiguing tasks.

Effect of catecholamines stimulation via hand cooling and the priming effect on the oxygen consumption kinetics

Introduction&#x0D; Priming effect has been shown to accelerate the oxygen consumption (V̇O2) kinetics. This phenomenon could be explained by muscle oxygen (O2) enhanced delivery, motor unit recruitment or intracellular O2 enhanced utilization (Goulding et al. 2023). Catecholamines such as epinephrine (E) and norepinephrine (NE) are known to impact the cardiovascular system as well as the respiratory system and metabolic effects (Zouhal et al. 2008). The aim of this study is two folds. Observing the effect of increased E and NE induced by cold-water hand immersion on V̇O2 kinetic during heavy intensity exercise bout (HCWR). Compare the effect of cold-water hand immersion and previous HCWR on V̇O2 kinetic to see if the sympathetic system could partially explain the priming effects.&#x0D; Methods&#x0D; Ten healthy active males (mean ± SD, age 23 ± 5 years, body mass 71 ± 6.5 kg) participated in this study. An incremental test was performed on ergometer to prescribe the intensity for the HCWR exercise (∆ 25%). Participants did an 8 min HCWR normal bout (NO), followed by 8 min rest and a second bout (SB) and hand cooling bout (HC) at heavy intensity in a randomized order. For the HC condition, participants put hands in cold water (0°C) for 2 min then directly did the HCWR. Blood samples has been taken at rest, before and directly after the HCWR.&#x0D; Results&#x0D; Just before exercise, all conditions were different, but HC E (1.095 ± 0.64 nmol/ml) increased by 347% while HC NE (6.98 ± 1.89 nmol/ml) matched values from SB NE (6.89 ± 2.22 nmol/ml). At the end of exercise, no significant difference has been found between NO E (1.44 ± 1.06) and HC E (1.54 ± 1.38 nmol/ml) while SB E (2.35 ± 1.55 nmol/ml) was significantly higher than both conditions but no differences have been found between HC (20.15 ± 8.76 nmol/ml) and SB (20.41 ± 9.74 nmol/ml) NE. V̇O2 kinetic has been sped up for both HC and SB by increasing the absolute primary prime amplitude of HC (33.88 ± 0.96 ml/min/kg),SB (34.60 ± 0.86ml/min/kg) compared to NO (32.75 ± 0.65 ml/min/kg) and reducing the prime amplitude of HC (3.22 ± 0.51 ml/min/kg), SB (2.90 ± 0.64 ml/min/kg) vs NO (3.87 ±0 .56 ml/min/kg) of the slow component of V̇O2.&#x0D; Discussion/Conclusion&#x0D; Catecholamines stimulation via hand cooling accelerated the V̇O2 kinetics enhancing the primary phase and reducing the slow component. This effect seemed to follow the priming effect but with less intensity. Increased O2 delivery appeared to be a common feature of both conditions, Motor neuron excitability due to increased NE was also a likely hypothesis, as both HC and SB had the same values just before exercise. Finally, intra-muscular enhancement illustrated by improved intracellular partial pressure kinetics and mitochondrial O2 utilization might explain the effects of catecholamines and part of the priming effect. Mitochondrial “warm-up” could be influenced by both catecholamines and priming effect resulting in a better production of adenosine triphosphate.&#x0D; References&#x0D; Goulding, R. P., Burnley, M., &amp; Wüst, R. C. I. (2023). How priming exercise affects oxygen uptake kinetics: From underpinning mechanisms to endurance performance. Sports Medicine, 53, 959-976. https://doi.org/10.1007/s40279-023-01832-1&#x0D; Zouhal, H., Jacob, C., Delamarche, P., &amp; Gratas-Delamarche, A. (2008). Catecholamines and the effects of exercise, training and gender. Sports Medicine 38, 401-423. https://doi.org/10.2165/00007256-200838050-00004

Acute psycho-physiological responses to submaximal constant-load cycling under intermittent hypoxia-hyperoxia vs. hypoxia-normoxia in young males.

Hypoxia and hyperoxia can affect the acute psycho-physiological response to exercise. Recording various perceptual responses to exercise is of particular importance for investigating behavioral changes to physical activity, given that the perception of exercise-induced pain, discomfort or unpleasure, and a low level of exercise enjoyment are commonly associated with a low adherence to physical activity. Therefore, this study aimed to compare the acute perceptual and physiological responses to aerobic exercise under intermittent hypoxia-hyperoxia (IHHT), hypoxia-normoxia (IHT), and sustained normoxia (NOR) in young, recreational active, healthy males. Using a randomized, single-blinded, crossover design, 15 males (age: 24.5 ± 4.2 yrs) performed 40 min of submaximal constant-load cycling (at 60% peak oxygen uptake, 80 rpm) under IHHT (5 × 4 min hypoxia and hyperoxia), IHT (5 × 4 min hypoxia and normoxia), and NOR. Inspiratory fraction of oxygen during hypoxia and hyperoxia was set to 14% and 30%, respectively. Heart rate (HR), total hemoglobin (tHb) and muscle oxygen saturation (SmO2) of the right vastus lateralis muscle were continuously recorded during cycling. Participants' peripheral oxygen saturation (SpO2) and perceptual responses (i.e., perceived motor fatigue, effort perception, perceived physical strain, affective valence, arousal, motivation to exercise, and conflict to continue exercise) were surveyed prior, during (every 4 min), and after cycling. Prior to and after exercise, peripheral blood lactate concentration (BLC) was determined. Exercise enjoyment was ascertained after cycling. For statistical analysis, repeated measures analyses of variance were conducted. No differences in the acute perceptual responses were found between conditions (p ≥ 0.059, ηp 2 ≤ 0.18), while the physiological responses differed. Accordingly, SpO2 was higher during the hyperoxic periods during the IHHT compared to the normoxic periods during the IHT (p < 0.001, ηp 2 = 0.91). Moreover, HR (p = 0.005, ηp 2 = 0.33) and BLC (p = 0.033, ηp 2 = 0.28) were higher during IHT compared to NOR. No differences between conditions were found for changes in tHb (p = 0.684, ηp 2 = 0.03) and SmO2 (p = 0.093, ηp 2 = 0.16). IHT was associated with a higher physiological response and metabolic stress, while IHHT did not lead to an increase in HR and BLC compared to NOR. In addition, compared to IHT, IHHT seems to improve reoxygenation indicated by a higher SpO2 during the hyperoxic periods. However, there were no differences in perceptual responses and ratings of exercise enjoyment between conditions. These results suggest that replacing normoxic by hyperoxic reoxygenation-periods during submaximal constant-load cycling under intermittent hypoxia reduced the exercise-related physiological stress but had no effect on perceptual responses and perceived exercise enjoyment in young recreational active healthy males.

Continuous Monitoring of Interstitial Fluid Glucose Responses to Endurance Exercise with Different Levels of Carbohydrate Intake.

We compared the 24 h changes in interstitial fluid glucose concentration (IGC) following a simulated soccer match between subjects consuming a high-carbohydrate (HCHO; 8 g/kg BW/day) diet and those consuming a moderate-carbohydrate (MCHO; 4 g/kg BW/day) diet. Eight active healthy males participated in two different trials. The subjects were provided with the prescribed diets from days 1 to 3. On day 3, the subjects performed 90 min (2 bouts × 45 min) of exercise simulating a soccer match. The IGC of the upper arm was continuously monitored from days 1 to 4. No significant difference in the IGC was observed between trials during exercise. The total area under the curve (t-AUC) value during exercise did not significantly differ between the HCHO (9719 ± 305 mg/dL·90 min) and MCHO (9991 ± 140 mg/dL·90 min). Serum total ketone body and beta-hydroxybutyrate concentrations were significantly higher in the MCHO than in the HCHO after a second bout of exercise. No significant differences in the IGC were observed between trials at any time point during the night after exercise (0:00-7:00). In addition, t-AUC value during the night did not significantly differ between the HCHO (32,378 ± 873 mg/dL·420 min) and MCHO (31,749 ± 633 mg/dL·420 min). In conclusion, two days of consuming different carbohydrate intake levels did not significantly affect the IGC during a 90 min simulated soccer match. Moreover, the IGC during the night following the exercise did not significantly differ between the two trials despite the different carbohydrate intake levels (8 vs. 4 g/kg BW/day).

Intra-Session Reliability of Sprint Performance on a Non-Motorised Treadmill for Healthy Active Males and Females.

This study examined the intra-session reliability of sprint performance on a non-motorized treadmill amongst healthy, active male and female adults. One hundred and twenty participants (males n = 77; females n = 45) completed two familiarization sessions, followed by a third session that consisted of three trials (T1, T2, T3) of maximal sprints (4-s), interspersed by three minutes of recovery. Combining males and females exhibited moderate-to-excellent test-retest reliability (intra-class correlation coefficient, ICC), minimal measurement error (coefficient of variation, CV) and trivial differences between trials (effect size, ES) for speed, power, total work and acceleration (ICC = 0.82-0.98, CV = 1.31-8.45%, ES = 0.01-0.22). The measurement error was improved between comparisons of T1 vs. T2 (CV = 1.62-8.45%, ES = 0.12-0.22) to T2 vs. T3 (CV = 1.31-6.56%, ES = 0.01-0.07) and better for females (CV = 1.26-7.94%, ES = 0.001-0.26) than males (CV = 1.33-8.53%, ES = 0.06-0.31). The current study demonstrated moderate-to-excellent reliability and good-moderate measurement error during a 4-s sprint on a non-motorized treadmill. However, sex had a substantial impact with females exhibiting better values. Practitioners should employ at least two separate trials within a session, in addition to multiple familiarization sessions, to achieve reliable non-motorized treadmill sprint performances.

An Acute Bout of Endurance Exercise Does Not Prevent the Inhibitory Effect of Caffeine on Glucose Tolerance the following Morning.

Caffeine reduces glucose tolerance, whereas exercise training improves glucose homeostasis. The aim of the present study was to investigate the effect of caffeine on glucose tolerance the morning after an acute bout of aerobic exercise. Methods: The study had a 2 × 2 factorial design. Oral glucose tolerance tests (OGTT) were performed after overnight fasting with/without caffeine and with/without exercise the evening before. Eight healthy young active males were included (Age 25.5 ± 1.5 years; 83.9 ± 9.0 kg; VO2max: 54.3 ± 7.0 mL·kg-1·min-1). The exercise session consisted of 30 min cycling at 71% of VO2max followed by four 5 min intervals at 84% with 3 min of cycling at 40% of VO2max between intervals. The exercise was performed at 17:00 h. Energy expenditure at each session was ~976 kcal. Lactate increased to ~8 mM during the exercise sessions. Participants arrived at the laboratory the following morning at 7.00 AM after an overnight fast. Resting blood samples were taken before blood pressure and heart rate variability (HRV) were measured. Caffeine (3 mg/kg bodyweight) or placebo (similar taste/flavor) was ingested, and blood samples, blood pressure and HRV were measured after 30 min. Next, the OGTTs were initiated (75 g glucose dissolved in 3 dL water) and blood was sampled. Blood pressure and HRV were measured during the OGTT. Caffeine increased the area under curve (AUC) for glucose independently of whether exercise was done the evening before (p = 0.03; Two-way ANOVA; Interaction: p = 0.835). Caffeine did not significantly increase AUC for C-peptides compared to placebo (p = 0.096), and C-peptide response was not influenced by exercise. The acute bout of exercise did not significantly improve glucose tolerance the following morning. Diastolic blood pressure during the OGTT was slightly higher after intake of caffeine, independent of whether exercise was performed the evening before or not. Neither caffeine nor exercise the evening before significantly influenced HRV. In conclusion, caffeine reduced glucose tolerance independently of whether endurance exercise was performed the evening before. The low dose of caffeine did not influence heart rate variability but increased diastolic blood pressure slightly.

Reliability of Near-Infrared Spectroscopy with and without Compression Tights during Exercise and Recovery Activities.

Near-infrared spectroscopy (NIRS) is widely used in sports science research, despite the limited reliability of available data. The aim of the present study was to assess the reliability of NIRS with and without compression tights. Thirteen healthy active males, (age 21.5 ± 2.7 years, body mass 82.1 ± 11.2 kg, BMI 24.6 ± 3.2 kg·m-2) completed four trials (two control trials and two trials using compression tights) over a 28-day period. During each trial, participants completed 20 min each of laying supine, sitting, walking (4 km·h-1), jogging, and sitting following the jogging. An NIRS device was attached to the muscle belly of the vastus lateralis and gastrocnemius and recorded tissue saturation index (TSI), muscle oxygenation, and muscle deoxygenation. Systematic bias and 95% limits of agreement (LOA) and coefficient of variation (CV) were used to report reliability measures for each activity type. For TSI, systematic bias (LOA) at the gastrocnemius during the control and tights trial ranged from -0.4 to 1.7% (4.4 to 10.3%) and -1.9 to 3.5% (8.1 to 12.0%), respectively. For the vastus lateralis, the systematic bias (LOA) for the control trial ranged from -2.4 to 1.0% (5.1 to 6.9%) and for the tights trial was -0.8 to 0.6% (7.0 to 9.5%). For TSI, the CV during the control trial ranged from 1.7 to 4.0% for the gastrocnemius and 1.9 to 2.6% for the vastus lateralis. During the tights trials, the CV ranged from 3.0 to 4.5% for the gastrocnemius and 2.6 to 3.5% for the vastus lateralis. The CV for muscle oxygenation during the control and tights trials for the gastrocnemius was 2.7 to 6.2% and 1.0 to 8.8% and for the vastus lateralis was 0.6 to 4.0% and 4.0 to 4.5%, respectively. The relative reliability was poorer in the tights trials, but if the aim was to detect a 5% difference in TSI, NIRS would be sufficiently reliable. However, the reliability of muscle oxygenation and deoxygenation varies considerably with activity type, and this should be considered when determining whether to employ NIRS in research studies.

Circulating and skeletal muscle microRNA profiles are more sensitive to sustained aerobic exercise than energy balance in males.

MicroRNAs (miRNAs) regulate molecular processes governing muscle metabolism. Physical activity and energy balance influence both muscle anabolism and substrate metabolism, but whether circulating and skeletal muscle miRNAs mediate those effects remains unknown. This study assessed the impact of sustained physical activity with participants in energy balance (BAL) or deficit (DEF) on circulating and skeletal muscle miRNAs. Using a randomized cross-over design, 10 recreational active healthy males (mean±SD, 22±5 years, 87±11kg) completed 72h of high aerobic exercise-induced energy expenditures in BAL (689±852kcal/day) or DEF (-2047±920kcal/day). Blood and muscle samples were collected under rested/fasted conditions before (PRE) and immediately after 120min load carriage exercise bout at the end (POST) of the 72h. Trials were separated by 7days. Circulating and skeletal muscle miRNAs were measured using microarray RT-qPCR. Independent of energy status, 36 circulating miRNAs decreased (P<0.05), while 10 miRNAs increased and three miRNAs decreased in skeletal muscle (P<0.05) at POST compared to PRE. Of these, miR-122-5p, miR-221-3p, miR-222-3p and miR-24-3p decreased in circulation and increased in skeletal muscle. Two circulating (miR-145-5p and miR-193a-5p) and four skeletal muscle (miR-21-5p, miR-372-3p, miR-34a-5p and miR-9-5p) miRNAs had time-by-treatment effects (P<0.05). These data suggest that changes in miRNA profiles are more sensitive to increased physical activity compared to energy status, and that changes in circulating miRNAs in response to high levels of daily aerobic exercise are not reflective of changes in skeletal muscle miRNAs. KEY POINTS: Circulating and skeletal muscle miRNA profiles are more sensitive to high levels of aerobic exercise-induced energy expenditure compared to energy status. Changes in circulating miRNA in response to high levels of daily sustained aerobic exercise are not reflective of changes in skeletal muscle miRNA.

Acute Effects of Static Self-Stretching Exercises and Foam Roller Self-Massaging on the Trunk Range of Motions and Strength of the Trunk Extensors

Although the effectiveness of static self-stretching exercises (SSSEs) and foam roller self-massaging (FRSM) in joint range of motion and muscle strength of the lower limbs has been extensively investigated, little is known about their effectiveness on the posterior trunk muscles. The present study aimed to investigate the acute effects of two 7-min SSSEs and FRSM intervention protocols on the range of trunk movements and the strength of the trunk extensors. Twenty-five healthy active males (n = 14) and females (n = 11) performed each intervention separately, one week apart. The range of motion (ROM) of the trunk-hip flexion (T-HF), the ROM of the trunk side-flexion (TSF) and rotation (TR) bilaterally, as well as the isometric maximum strength (TESmax) and endurance (TESend) of the trunk extensors were measured before and after each intervention. The ROMs of T-HF, TSF, and TR were significantly increased following both SSSEs and FRSM. The TESmax and TESend were also significantly increased after FRSM, but decreased following SSSEs. While both interventions were effective in increasing the range of motion of the trunk, a single 7-min session of FRSM presented more advantages over a similar duration SSSEs protocol due to the increase in the strength of the trunk extensors it induced.

Impact of Three Consecutive Days of Endurance Training Under Hypoxia on Muscle Damage and Inflammatory Responses.

Purpose: The purpose of this study was to determine the effect of 3 consecutive days of endurance training under hypoxia on muscle damage, inflammation, and performance responses.Methods: Nine active healthy males completed two trials in different periods, consisting of either 3 consecutive days of endurance training under hypoxia [fraction of inspired oxygen (Fio2): 14.5%, HYP] or normoxia (Fio2: 20.9%, NOR). They performed daily 90-min sessions of endurance training consisting of high-intensity endurance interval pedaling [10 × 4-min pedaling at 80% of maximal oxygen uptake () with 2 min of active rest at 30% of ] followed by 30-min continuous pedaling at 60% of during 3 consecutive days (days 1–3). Venous blood sample, muscular performance of lower limb, and score of subjective feelings were determined every morning (days 1–4) to evaluate muscle damage and inflammation. On day 4, subjects performed an incremental exercise test (IET) to evaluate the performance response.Results: Pedaling workload during daily endurance training was significantly lower in the HYP trial (interval exercise: 166 ± 4 W) than in the NOR trial (194 ± 8 W; P < 0.0001). Serum creatine kinase (CK) and high-sensitivity C-reactive protein (hsCRP) concentrations did not significantly change during days 1–4 in either trial. Maximal voluntary contraction (MVC) of knee extension (P < 0.0001) and drop jump (DJ) index (P = 0.004) were significantly decreased with training in both trials, with no significant difference between trials. The muscle soreness and fatigue scores significantly increased in both trials (P < 0.0001). However, the HYP trial showed a significantly lower score of fatigue on day 4 compared with the NOR trial (P = 0.004). Maximal aerobic power output during IET on day 4 did not significantly differ between trials.Conclusion: Three consecutive days of endurance training under hypoxia induced comparable levels of muscle damage, inflammation, and performance responses compared with the same training under normoxia.

A STUDY OF FACTORS AFFECTING THE LEVEL OF HAPPINESS AMONGST PRACTITIONERS OF YOGA, AEROBICS AND WALKING DURING CORONA LOCKDOWN

Fitness and Yoga has been the focus of studies in recent decades for the not only the general well-being but also a therapeutic modality for mental stress, obesity, and other lifestyle disorders. Individual studies indicate positive effects of exercises like aerobics, walking and yoga under covid-19 lockdown conditions, suggesting that they can be used as non-pharmacological and as non-invasive interventions or as a supplement to drug therapy for the prevention and treatment of various mental and physical conditions. 120 moderately active healthy males (59) and females (61) volunteered to participate in the survey study with the aim to study the level of happiness and related variables age, body mass index, level of education and choice of physical activity of the participants. Oxford Happiness Questionnaire (OHQ) developed by psychologists Michael Argyle and Peter Hills at Oxford University was used to collect data. Results showed that there was no statistically significant difference in the choice of activity out of the three namely: aerobics, yoga and walking to stay fit and healthy. The level of happiness was found to be better for those who spent a greater number of years in school/college/university and another finding was that the level happiness was lower amongst the participants who were of more age as compared to the ones who were of lesser age. There was a significant difference in the level of happiness amongst the walkers, aerobic practitioners and yoga practitioners. It was not possible however to point out exactly the magnitude of difference between the three groups because the data was non-parametric. No gender differences were observed amongst males and females on level of happiness on activities chosen by the participants (aerobics, yoga and walking) to stay fit and healthy. Significant differences amongst the participants were observed amongst the underweight, normal weight and overweight participants

Fatigue-Induced Inter-Limb Asymmetries in Strength of the Hip Stabilizers, Postural Control and Gait Following a Unilateral Countermovement Vertical Jump Protocol.

It is generally accepted that neuromuscular overload and fatigue of one lower limb can affect the functional ability of the ipsilateral limb, and possibly the contralateral limb, increasing the likelihood of injury. The purpose of the current study was to examine the effect of a unilateral countermovement vertical jump (UCVJ) fatigue protocol on the neuromuscular function of the ipsilateral as well as the contralateral lower limb. The isometric strength of the hip stabilizers, postural control via posturographic analysis during the Y-Balance-Test (YBT), and the stance-phase-of-gait were assessed in 24 healthy physical active males and females before and after execution of a UCVJ fatigue protocol. The fatigue protocol included 5 sets of 20 maximum UCVJs performed on the supportive leg, with a 30-s break between sets. Following a 16.8% decline in vertical jump performance and an associated 2.3-fold increase in perceived exertion, our findings revealed significant post-fatigue inter-limb differences regarding postural control. The post-fatigue inter-limb differences regarding the isometric strength of the hip stabilizers and the stance-phase-of-gait parameters were not significant. Our findings showed that a 100 UCVJs session is likely to induce significant inter-limb differences in postural control, possibly increasing the risk of lower limb injury.

Hepcidin response to three consecutive days of endurance training in hypoxia.

The purpose of this study was to determine the effects of 3 consecutive days of endurance training in hypoxia on hepcidin responses. Nine active healthy males completed two trials, consisting of 3 consecutive days of endurance training in either hypoxia [fraction of inspired oxygen (FiO2): 14.5%) or normoxia (FiO2: 20.9%). On days 1-3, participants performed one 90min session of endurance training per day, consisting of high-intensity endurance interval exercise [10 × 4min of pedaling at 80% of maximal oxygen uptake ([Formula: see text]O2max) with 2min of active rest at 30% of [Formula: see text]O2max] followed by 30min of continuous exercise at 60% of [Formula: see text]O2max. Venous blood samples were collected prior to exercise each day during the experimental period (days 1-4) to determine serum hepcidin, iron, ferritin, haptoglobin, and ketone body concentrations. Serum iron (p < 0.0001), ferritin (p = 0.005) and ketone body (p < 0.0001) concentrations increased significantly in both trials on days 2-4 compared with day 1, with no significant differences between trials. No significant changes in serum haptoglobin concentrations were observed throughout the experimental period in either trial. Serum hepcidin concentrations also increased significantly on days 2-4 compared with day 1 in both trials (p = 0.004), with no significant differences observed between trials. 3 consecutive days of endurance training in hypoxia did not affect hepcidin concentrations compared with endurance training in normoxia.

Normative data and correlation between dynamic knee valgus and neuromuscular response among healthy active males: a cross-sectional study

The dynamic knee valgus (DKV) during different sport maneuvers has been widely described as risk factor to develop an anterior cruciate ligament injury. Hip and knee muscles seem to have a crucial role to prevent the dynamic knee valgus. This study aimed to give normative and correlational data about DKV and hip and knee neuromuscular response (NMR) among healthy active males. The hypothesis is that DKV could be correlated with hip NMR. A cross-sectional correlational study. Research Anatomy Laboratory. The study was carried out among 50 active, non-injured males. Dynamic Knee-Valgus angle and lower limb posterior chain muscles Neuromuscular Response. DKV was measured using Kinovea software during a Single-Legged Drop Jump test and NMR was measured using tensiomyography and myotonometry for gluteus maximum, biceps femoris, semitendinosus, lateral and medial gastrocnemius. Right and left limbs were both performed and analyzed independently. No significant correlation was observed between DKV and hip and knee muscles NMR. This study shows normative and correlational data about dynamic knee valgus, tensiomyography and myotonometry for healthy and active males. The DKV control seems to be non-correlated with isolated hip and knee muscles NMR so this suggests it is more about Central Nervous System activity than about isolated muscles NMR.

Training-induced changes in anterior pelvic tilt: potential implications for hamstring strain injuries management

ABSTRACT An association has been reported between dynamic anterior pelvic tilt (APT) and hamstring injuries; however, no research has examined if a training-based preventive intervention could alter APT. Therefore, the aim of the present study was to examine if a specific 6-week multimodal intervention, based on the theoretical influence of neighbouring joints and biomechanical interactions between muscles that are inserted to the pelvis, induced changes in APT, during walking gait, hamstring flexibility and trunk endurance. Thirty-five active healthy males volunteered for this single-blind controlled trial and were split into two groups based on baseline data: a control group (CG, n = 20, continued their normal physical activities), and an intervention group (IG, n = 15, performed the intervention programme for 18 sessions over 6 weeks). A significant (p = 0.001) decrease in the APT kinematics during gait, significant increase in the Active Knee Extension Test (p = 0.001), and a significant increase in trunk endurance performance for flexion (p = 0.001), extension (p = 0.001) and side bridge (p = 0.001) were observed, in IG after the 6-week programme, compared to CG.