Search Results (95)

This study investigates the effect of repeated exposure to optic flow in virtual reality (VR) on postural control in upright standing in older adults. Eighteen participants (>60 years) completed pre/post assessments consisting of quiet standing in a real environment (eyes open/closed), postural responses to simulated forward and backward self-motion in VR, and proprioceptive perturbations induced by bilateral Achilles and tibialis anterior tendon vibration. Intra- (within similar sensory modality) and inter-modal correlations (within different sensory modalities inducing similar directional postural response) were also investigated to provide insight into sensory integration strategies. The intervention consisted of six 100-s VR bouts alternating simulated forward and backward self-motion. Postural outcomes were quantified from force platform recordings as center of pressure (CoP) velocity and excursion. Repeated VR exposure reduced CoP velocity during simulated forward and backward self-motion (p < 0.05). After the intervention, CoP velocity decreased when standing with eyes closed (p < 0.05) but not when eyes were open. Postural response to tendon vibration was not modified by the intervention (p > 0.05). After the intervention, intra-modal correlation for postural responses to optic flow appeared, whereas a pre-existing inter-modal association between Achilles vibration and forward optic flow disappeared. These results indicate that the postural control system remains adaptable in older adults and highlight the potential of VR environments to improve balance in older adults. Full article

Evidence suggests that physical activity promotes bone health through mechanical loading and biochemical signaling between bone and muscle tissues. A class of signaling molecules known as exerkines is a key mediator of bone–muscle crosstalk. Although exercise regulates osteokines, the acute exerkine responses across different exercise modalities remain unclear. This randomized repeated-measures crossover study compared acute changes in serum sclerostin (SCL), dickkopf-1 (DKK-1), receptor activator of nuclear factor kappa-B ligand (RANKL), osteopontin (OPN), brain-derived neurotrophic factor (BDNF), irisin, and interleukin 6 (IL-6) following circuit training (CT) (cycle ergometer, push-up, step-ups, medicine ball twist, and front squats with kettlebell for three rounds) and traditional resistance (TR) exercise (3 sets 10 repetitions 50–60% 1 RM for leg press, seated cable row, barbell bench press, dumbbell deadlifts, and dumbbell seated shoulder press) in healthy young adults (n = 12). Participants performed two protocols separated by 2-week wash-out periods. Blood samples were analyzed before exercise training (pre), immediately post-exercise (IP), and 30 min post-exercise (30P) for all exerkines using ELISA. There was a significant interaction between protocol, timepoint, and sex (p = 0.038) for SCL levels. In males, SCL levels increased from Pre to IP under both training protocols (CT: 0.10 ± 0.02 ng/mL to 0.14 ± 0.02 ng/mL; TR: 0.20 ± 0.02 ng/mL to 0.21 ± 0.02 ng/mL). In both protocols, SCL levels decreased from IP to 30 P (CT: 0.14 ± 0.02 to 0.10 ± 0.01 ng/mL; TR: 0.22 ± 0.02 to 0.17 ± 0.02 ng/mL). In females, SCL levels increased from Pre to IP under both training protocols (CT: 0.03 ± 0.02 ng/mL to 0.06 ± 0.02 ng/mL; TR: 0.07 ± 0.02 ng/mL to 0.13 ± 0.02 ng/mL). There was a significant time effect for OPN and RANKL concentrations. Marginal means for the time point showed that OPN was significantly higher at the Pre time point. Post hoc analyses showed that OPN levels significantly decreased from 30P to Pre (18.84 ± 0.92 to 15.69 ± 1.32 pg/mL) (p = 0.01). RANKL showed a significant increase from Pre (0.38 ± 0.04 pg/mL) to 30P (0.57 ± 0.06 pg/mL) (p = 0.02); otherwise, there were no significant differences between protocols or sexes. Irisin significantly decreased from Pre (28,761.73 ± 238.52 pg/mL) to IP (2364.85 ± 243.79 pg/mL) in both protocols (p = 0.01). DKK-1, BDNF, and IL-6 levels were only different between protocols (p < 0.01). SCL and BDNF levels were expressed higher in the TR protocol, whereas DKK-1, IL-6, and Irisin levels were expressed higher in the CT protocol. Overall, the findings suggest that SCL, RANKL, OPN, and irisin responded to the exercise bout, while the other exerkines did not show meaningful changes over time. Full article

This study examined whether acute exercise performed within individualized physiological intensity zones affects multidimensional soccer shooting performance. Twenty male collegiate soccer players completed a Yo-Yo Intermittent Recovery Test Level 1 with portable gas analysis to determine the ventilatory threshold (VT) and respiratory compensation point (RCP). Three individualized zones were defined: Low (<VT), Moderate (VT–RCP), and High (>RCP). In a randomized design, players completed three 3 min shuttle-running bouts, each followed immediately by the 356 Soccer Shooting Test. Ball velocity (BV), shooting accuracy (SA), and shooting quality (SQ) were analyzed using repeated-measures ANOVA. Exercise condition significantly affected SA (p = 0.013) and SQ (p = 0.007), but not BV (p = 0.216). Bonferroni-adjusted comparisons showed that SA and SQ were lower in High than in Low, whereas no pairwise BV comparison reached significance. A sensitivity analysis using all ten recorded attempts rather than the original best-seven scoring approach showed an overall condition effect for BV without a significant pairwise comparison, retained overall effects for SA and SQ, and showed that the Low–High contrast remained robust only for SQ. Baseline comparisons were not significant. These findings indicate condition-specific shooting responses, with the clearest evidence for lower SQ after High compared with Low, supportive evidence for lower SA, and no significant primary condition effect for BV. Full article

Purpose: This study investigated whether an acute bout of submaximal unilateral arm cycling elicits sustained changes in corticospinal excitability (CSE) and short-interval intracortical inhibition (SICI) in the homologous muscles of the non-exercised, resting limb. A secondary aim was to determine whether prior exercise induces a preconditioning effect on subsequent motor output. Methods: Transcranial magnetic stimulation was used to assess motor evoked potential (MEP) amplitude (single-pulse) and SICI (paired-pulse) in the resting non-dominant flexor carpi radialis (FCR) and extensor carpi radialis (ECR) muscles of healthy participants. Measures were obtained at rest, during a 10 min bout of unilateral arm cycling (30 W, 60 rpm), and throughout a 20 min recovery period. To assess potential preconditioning effects, measurements were repeated during a second 2 min cycling bout following a 20 min recovery. Rest and exercise conditions were analyzed separately due to differences in stimulation intensity (RMT vs. AMT). Results: Unilateral arm cycling did not produce sustained changes in CSE or SICI in the resting limb when both arms were at rest. Furthermore, unilateral arm cycling followed by a 20 min recovery period did not result in a preconditioning effect, as CSE in the resting limb was not enhanced during a subsequent unilateral arm cycling bout. Conclusions: Submaximal unilateral arm cycling induces a transient, state-dependent increase in CSE to the non-exercised limb without altering SICI. The absence of SICI modulation suggests that this facilitation is not mediated by GABA_A-dependent intracortical mechanisms, and may instead reflect modulation arising from spinal and interlimb locomotor circuitry. The lack of sustained post-exercise effects indicates that low-intensity arm cycling does not induce a plasticity-permissive cortical state, highlighting a distinction between transient, movement-dependent facilitation and longer-lasting exercise-induced neuroplasticity. Full article

At the dawn of the 20th century, seminal studies revealed that muscle fibers produce less heat and generate greater force during elongation than during shortening actions, laying the foundation for contemporary research on eccentric exercise. Today, eccentric exercise is widely used by athletes to enhance strength and by older adults to maintain functional capacity, yet it may cause muscle damage, particularly in unaccustomed muscles. Despite more than a century of investigation, the precise mechanisms of eccentric exercise-induced muscle damage remain incompletely resolved. Nevertheless, eccentric exercise serves as a valuable model for studying muscle injury and repair and adaptation. This review organizes current evidence into nine key themes: (1) eccentric exercise-induced muscle damage and flawed biomarkers, (2) satellite cell-mediated and alternative repair pathways, (3) high-force, low-cost contractions and metabolic impact, (4) repeated bout effect and protective adaptations, (5) architectural remodeling of fascicles, sarcomeres and tendon, (6) distinct neural control, proprioception, and cross-education adaptations, (7) mitochondrial, sarcoplasmic reticulum, and cytoskeletal stress remodeling, (8) connective tissue perturbation, remodeling, and joint stability, and (9) targeted, cautious use of antioxidant supplementation. Rather than offering a comprehensive overview, this review highlights pivotal experiments, concepts, and controversies within these themes to guide readers to the most impactful discoveries in eccentric exercise and muscle damage. Full article

Vascular ageing is a complex process marked by progressive endothelial dysfunction, chronic low-grade inflammation (“inflammageing”), and reduced regenerative capacity, driven in part by an imbalance between protective endothelial autophagy and cellular senescence characterized by a proinflammatory senescence-associated secretory phenotype (SASP). Disruption of this autophagy–senescence axis accelerates vascular inflammation, arterial stiffening, and atherogenesis. High-intensity interval training (HIIT), consisting of repeated bouts of near-maximal anaerobic effort with recovery periods, is widely used by both elite and recreational athletes and is increasingly recognized as an effective nonpharmacological strategy to enhance endothelial function, arterial elasticity, and mitochondrial biogenesis. However, excessively intense or poorly structured HIIT, particularly in the absence of adequate recovery or in individuals with underlying cardiometabolic or vascular vulnerability, may induce endothelial stress and promote maladaptive vascular remodelling, including calcification and plaque instability. These considerations underscore the need for refined individualized exercise prescription strategies that balance performance benefits with endothelial protection. Based on these observations, here, we introduce a novel conceptual framework, “shear dose–calibrated HIIT,” designed to understand and define an optimal shear dose capable of maximizing autophagic flux while minimizing SASP activation. Experimental and clinical evidence of HIIT-induced effects on flow-mediated dilation (FMD), pulse wave velocity (PWV), and redox biomarkers is presented, followed by the proposal of a biomarker panel for assessing autophagic flux and cellular senescence in peripheral samples (peripheral blood mononuclear cells (PBMCs), extracellular vehicles (EVs), and plasma). This integrative approach, which combines vascular mechanotransduction, redox biology, and autophagic signalling, provides a novel translational perspective on how individually calibrated HIIT can promote vascular longevity and reduce cardiometabolic risk associated with aging and metabolic syndrome. Full article

High-intensity aquatic sports require athletes to repeatedly produce near-maximal efforts under conditions of constrained ventilation and limited recovery between bouts, placing substantial importance on recovery efficiency. While supplemental oxygen has been proposed as a recovery-targeted strategy to support repeated high-intensity performance, its acute effects in aquatic athletes remain poorly characterized. The purpose of this study was to examine whether brief inhalation of supplemental oxygen during recovery following a maximal swim effort influences subsequent swimming performance and perceived exertion in trained aquatic athletes. Eighteen collegiate-aged male aquatic athletes completed a randomized, placebo-controlled, within-subject crossover protocol. Each condition consisted of a maximal 100-yard (91.44 m) swim followed by a standardized recovery period that included a five second inhalation of either 98% supplemental oxygen or ambient air delivered via an identical portable device, prior to a maximal 50-yard (45.72 m) freestyle sprint. Sprint performance was significantly faster following oxygen-assisted recovery compared with placebo, and perceived exertion was significantly reduced at the post-exercise time point, with no differences observed prior to exercise or mid-protocol. These findings suggest that brief, recovery-targeted hyperoxia may enhance repeated high-intensity swimming performance while attenuating post-exercise perceived exertion in trained aquatic athletes. Full article

Background: Due to its high polyphenol content and purported capability to mitigate post-exercise muscle soreness and promote recovery, tart cherry (TC) supplementation has been proposed to enhance recovery and athletic performance. This study examined the effects of powdered TC supplementation on various recovery and performance metrics following a repeated sprint exercise protocol in physically active young adults. Methods: 40 (18 M, 22 F) healthy, active participants (24.6 ± 5.5 yrs, 171.5 ± 11 cm, 71.7 ± 14.5 kg, 24.2 ± 3.1 kg·m⁻²) participated in this randomized, double-blind, placebo-controlled, parallel study design. Placebo (PLA) or powdered TC supplementation (500 mg/day) occurred for ten days: seven days prior to, day of, and two days following repeated sprints (15 × 30 m with 1 min rest between sprints). Performance was assessed via the countermovement jump, isometric mid-thigh pull, isokinetic knee extension, and the Wingate anaerobic test. Recovery was evaluated using visual analog scales for soreness, recovery, and readiness to train. Muscle damage was evaluated using creatine kinase. These measures were evaluated at baseline, and at 1 h, 24 h, and 48 h post-exercise. Results: Significant main effects of time were observed with recovery VAS (p < 0.001), readiness to train VAS (p < 0.001), and jump height (p = 0.014) experiencing similar reductions, while soreness VAS (p < 0.001) and creatine kinase (p = 0.05) experienced similar increases in response to the repeated sprint protocol and supplementation. Across all measurements, no significant group × time differences were observed for jump height (PLA:−6.7 ± 10.4% vs. TC: −11.0 ± 17.9%, p = 0.608), peak propulsive force (PLA: 0.3 ± 4.6% vs. TC: 2.2 ± 7.4%, p = 0.194), knee extension peak torque at 180°/s (PLA: 10.5 ± 73.5% vs. TC: −1.04 ± 49.6%, p = 0.335), readiness to train VAS (PLA: −23.0 ± 19.2% vs. TC: −14.7 ± 20.2%, p = 0.401), soreness VAS (PLA: 250 ± 323% vs. TC: 261 ± 432%, p = 0.838), recovery VAS (PLA: −24.6 ± 17.9% vs. TC: −8.2 ± 40.5%, p = 0.251), and creatine kinase (PLA: 22.8 ± 35.5% vs. TC: 90.4 ± 225.6%, p = 0.31). Conclusions: A single bout of repeated sprints was responsible for significant reductions in jump height, peak propulsive force, peak torque, and perceived readiness, while perceived soreness, myoglobin, and creatine kinase were significantly increased. Ten days of TC supplementation did not impact any change beyond what was observed in PLA for markers of recovery, readiness, soreness, exercise performance, and markers of muscle damage. Full article

Anxiety is a common psychological challenge among athletes, particularly in response to intense training sessions. This randomized crossover study investigated the immediate effects of a single session of focused attention meditation on anxiety, autonomic responses, and performance during high-intensity intermittent training (HIIT) in twenty-six university-level speed skaters. Participants completed three pre-exercise interventions (focused attention meditation, controlled breathing, and random thinking) on separate occasions in a randomized order. Following each intervention, participants performed a leg cycling-based HIIT protocol consisting of 20 s of maximal effort work followed by 10 s of passive rest, repeated for 8 sets using a cycling ergometer. State anxiety was assessed using the State–Trait Anxiety Inventory, and mood disturbance was evaluated using the Profile of Mood States. Autonomic and physiological responses were assessed via heart rate variability (coefficient of variation), oxygen uptake, and power output, measured before and after the intervention and the HIIT bout. Focused attention meditation significantly reduced state anxiety compared with random thinking (ΔSTAI: −5.0 [6.0] vs. −1.0 [4.3]; p < 0.05, effect size = 0.527), whereas controlled breathing primarily influenced heart rate variability (CV: 0.10 [0.11] vs. 0.07 [0.03]; p = 0.041, effect size = 0.736). No significant differences were observed among conditions in mean power output or fatigue index during HIIT. These findings suggest that single-session focused attention meditation may serve as a practical pre-exercise strategy for an immediate reduction in state anxiety, without compromising subsequent high-intensity exercise performance. Full article

The study aimed to determine the effect of acute, one-time physical effort performed under different environmental temperature conditions on erythrocyte deformability in healthy young men. This exploratory randomized parallel-group study involved 30 men randomly assigned to an experimental group exercising at −10 °C in a climatic chamber and a control group exercising under thermoneutral outdoor conditions. Erythrocyte deformability was assessed using the elongation index (EI), reflecting erythrocyte elasticity and the ability to pass through microcirculation vessels. Participants performed an incremental 20 m shuttle run test. Venous blood samples were collected before and immediately after exercise, and erythrocyte deformability was analyzed using a Lorrca analyzer across a shear stress range of 0.30–60.00 Pa. A two-factor repeated-measures analysis of variance was applied. An increase in EI after exercise was observed in both groups, predominantly at higher shear stress values, indicating enhanced erythrocyte deformability under conditions of increased shear forces. However, the magnitude of post-exertion changes differed between groups. At lower shear stress levels (0.30 Pa and 0.58 Pa), EI tended to decrease after exercise. These findings indicate that a single bout of physical effort influences erythrocyte deformability, while the potential effects of cold exposure on this response remain uncertain and warrant further investigation. Full article

Animals scan their environment to detect threats. Such vigilance behaviour is costly, and animals adjust their vigilance to prevailing threats. Waterholes are dangerous places that attract predators, and require heightened vigilance. We investigated how Gouldian finches adjust their vigilance at waterholes by measuring the frequency of head movements and interscan interval while drinking. The frequency of head movements increased with increasing risk perception (a) from perching in the tree to being on the ground and (b) while drinking, with a higher frequency of movements recorded at small waterholes compared to medium and large ones. The latter adds to recent findings that small waterholes are perceived as more dangerous and require further investigation. With a predicted increase in droughts, birds will rely on small waterholes for longer during the dry season which might cause stress. Furthermore, interscan interval varied in terms of interaction with waterhole size and group size, indicating adjustments linked to perceived threat and social effects. Finally, frequency of head movements and interscan intervals were positively correlated. This might reflect different strategies to check the environment, with either a high frequency of head movements when scanning accompanied by long drinking bouts or looking in one direction for a longer time (lower vigilance) but repeating this behaviour at shorter intervals. Full article

Aim: To compare the effect of consuming three isocaloric diets that differed in macronutrient composition on substrate oxidation and glucose regulation during sustained submaximal exercise in adults with type 1 diabetes (T1D). Methods: In a randomised, crossover design, 12 adults with T1D (n = 4 female, age: 46 ± 15 years, HbA1c: 55.9 ± 7.8 mmol/mol) consumed three isocaloric diets over seven days: (i) HCLFLP (high-carbohydrate [48%], low-fat [33%], low-protein [19%]), (ii) LCHFLP (low-carbohydrate [19%]), high-fat [62%], low-protein [19%]), and (iii) LCLFHP (low-carbohydrate (19%), low-fat [57%], high-protein [24%]). On the morning of day eight, participants undertook 45 min of cycling (≈60% $\stackrel{.}{\mathrm{V}}$O_2peak) whilst fasting. Venous-derived plasma glucose and free fatty acids (FFA) were measured throughout the trial period. Indirect calorimetry was used to determine rates of substrate oxidation during exercise. Data were analysed via repeated measures ANOVAs with p ≤ 0.05 accepted as significant. Results: During exercise, rates of lipid oxidation were higher (1.2-fold, p = 0.030) and carbohydrate oxidation lower (0.8-fold, p = 0.030) in LCHFLP versus HCLFLP. Concentrations of FFA after exercise were higher in LCHFLP compared to HCLFLP (by ≈22%, p = 0.019). Overall time spent in euglycaemia was higher (HCLFLP: 55.6 ± 43.9, LCHFLP: 87.3 ± 28.7, LCLFHP: 95.2 ± 7.9%, p = 0.003) and hyperglycaemia lower (HCLFLP: 44.4 ± 43.9, LCHFLP: 12.7 ± 28.7, LCLFHP: 4.8 ± 7.9%, p = 0.003) in both LC diets relative to HC. No differences in any measured biomarkers were observed between the two LC diets. Conclusions: One-week consumption of isocaloric diets that differed in their macronutrient composition shifted patterns of energy metabolism during a standardised bout of moderate intensity exercise performed in the fasted state in adults with T1D. Full article

Background: Isometric handgrip (IHG) exercise reduces blood pressure (BP) in both normotensive and hypertensive individuals. However, there are few studies specifically addressing its effects in hypertensive patients with ischemic heart disease (IHD). This research aimed to compare acute hemodynamic responses and post-exercise hypotension to single bouts of IHG handgrip performed at two different intensities in patients with IHD. Methods: Fifty-four sedentary patients were enrolled and randomly assigned to one of three groups: (1) high-intensity isometric handgrip performed at 70% of maximal voluntary contraction (MVC) (IHG-70%); (2) low-intensity isometric handgrip performed at 30% of MVC (IHG-30%); (3) control group (no exercise). Heart rate and BP were measured, and transthoracic echocardiography was performed at baseline, during exercise (lasting 3 min), and after 15 min post-exercise. BP was also measured at 30, 45, and 60 min of recovery. Results: No significant changes in systolic BP occurred during the exercise phase between the three study groups. Systolic BP decreased significantly in IHG-70% compared to the control at 30 (−7.7 ± 1.9; p = 0.035) and 45 min (−8.1 ± 2.3; p = 0.021) post-exercise, while there were no significant differences between IHG-70% and IHG-30% at different time-points. There were no significant changes in diastolic BP between the two active groups and between IHG-70 and IHG-30 versus control at different time-points (repeated-measures ANOVA p = 0.257). Global work efficiency was unchanged in IHG-70% (−4%) and IHG-30% (+1%) compared to control (ANOVA p = 0.154). Conclusions: High-intensity and low-intensity isometric handgrip exercises did not cause hemodynamic impairment in IHD. High-intensity exercise was more effective than low-intensity in reducing post-exercise systolic BP. Full article

We examined the physiological demands of trained rowers across four exercise intensity domains (considering the effects of weight category and sex). Twenty-four trained rowers (12 lightweight and 12 heavyweight) performed 7 × 3 min incremental bouts on a Concept2 rowing ergometer (30 W power increases and 60 s rest intervals). Performance, cardiorespiratory and metabolic responses were continuously assessed throughout the experimental protocol to characterize internal load across progressive exercise intensities. Statistical analyses included a repeated measures ANOVA test and independent t-tests (p ≤ 0.05). Heavyweight rowers exhibited greater absolute anaerobic energy production in the severe domain (41.25 ± 10.39 vs. 32.54 ± 5.92 kJ) (p = 0.02), higher peak metabolic power (up to 1.57 ± 0.30 vs. 1.48 ± 0.30 kW) (p = 0.001) and greater total energy expenditure (up to 277.52 ± 51.23 vs. 266.69 ± 51.59 kJ) (p = 0.001) than lightweight rowers, whereas the latter showed comparable relative cardiorespiratory responses to heavyweights. With respect to sex differences, males demonstrated higher oxygen uptake (from ~43–59 vs. ~34–48 mL·kg⁻¹·min⁻¹) (p = 0.001), ventilation (from ~78–146 vs. ~49–99 L·min⁻¹) (p = 0.001), metabolic power (from ~1.1–1.7 vs. ~0.7–1.0 kW) (p = 0.001) and energy expenditure (from ~193–305 vs. ~119–209 kJ) (p = 0.001) across all intensity domains. However, blood lactate levels and anaerobic energy contributions were similar between sexes. These findings demonstrated that domain-based physiological profiling effectively differentiates internal responses among rowers by weight category and sex. Heavyweights showed greater absolute energy output, while lightweights demonstrated higher metabolic efficiency. Males had elevated cardiorespiratory and metabolic values, but relative bioenergetic responses were similar across groups. These findings support individualized training based on physiological profiles. Full article

Background/Objectives: Creatine and β-alanine are two widely used dietary supplements known to enhance exercise performance and improve body composition; however, less is known regarding the synergistic effects of combining the two supplements. Methods: A systematic search was conducted across PubMed/MEDLINE, Scopus, and Web of Science databases for randomized controlled trials (RCTs) published up to March 2025. Eligible studies included adult participants receiving creatine and β-alanine together compared to creatine or β-alanine alone for at least four weeks and assessed measures of exercise performance and/or body composition. Study quality was assessed using the Cochrane Risk of Bias tool. Results: A total of 7 randomized controlled trials (n = 263 participants; 231 males and 32 females) met the inclusion criteria. Collectively, the combination of creatine and β-alanine supplementation enhanced high-intensity exercise performance, particularly anaerobic power and repeated-bout performance, compared to creatine or β-alanine alone. Co-ingestion of creatine and β-alanine supplementation did not increase measures of maximal strength compared to creatine alone. The effects of creatine and β-alanine supplementation on body composition were equivocal, with one study reporting greater lean mass gains and fat mass reductions compared to creatine and β-alanine supplementation individually, while another found no significant improvements. Additionally, no significant improvements in aerobic endurance capacity (VO₂max, lactate threshold, or time to exhaustion) were observed from creatine and β-alanine supplementation co-ingestion. Conclusions: The combination of creatine and β-alanine supplementation may be effective for enhancing high-intensity exercise performance but has no greater effect on maximal strength, body composition, or measures of aerobic capacity compared to creatine or β-alanine alone. Full article