Min Rest Period Research Articles

Assessing Early Stage Open-Angle Glaucoma in Patients by Isolated-Check Visual Evoked Potential.

Recently, the isolated-check visual evoked potential (icVEP) technique was designed and has been reported to detect glaucomatous damage earlier and faster. It creates low spatial frequency/high temporal frequency bright stimuli and records cortical activity initiated primarily by afferents in the magnocellular ON pathway. This pathway contains neurons with larger volumes and axonal diameters, and it is preferentially damaged in early glaucoma, which can result in visual field loss. The study presented here uses standard operative procedures (SOP) of icVEP to obtain reliable results. It can detect visual function loss using a signal-to-noise ratio (SNR) corresponding to the defects of retinal nerve fiber layer (RNFL) in early stage open-angle glaucoma (OAG). A setting of 10 Hz and condition of 15% positive-contrast (bright) are selected to differentiate OAG patients and control subjects, with each check containing eight runs. Each run persists for 2 s (for 20 total cycles). A flowchart is constructed, which consists of pupil size and intraocular pressure over a 30 min rest period before each examination. Additionally, the testing order of eyes is performed to obtain reliable electroencephalographic signals. VEPs are recorded and analyzed automatically by software, and SNRs are derived based on a multivariate statistic. An SNR of ≤ 1 is considered abnormal. A receiver-operating-characteristic (ROC) curve is applied to analyze the accuracy of group classification. Then, the SOP is applied in a cross-sectional study, showing that icVEP can detect glaucomatous visual function abnormality in the central visual field in the form of SNR. This value also correlates with the thickness thinning of RNFL and produces high classification accuracy for early stage OAG. Thus, it serves as a useful and objective diagnostic technology for the early detection of glaucoma.

The effect of music on anaerobic exercise performance and muscular endurance.

Music has been shown to improve aerobic and anaerobic exercise performance; however, music's effect on resistance training exercise, gender differences, and heart rate (HR) is less understood. The purpose of this study was to examine the effects of self-selected music on anaerobic exercise performance using a bench press (BP) protocol and the Wingate anaerobic test (WAT). Fifteen (8 men; 7 women) healthy, college-aged students between 18-25 years old (20.1±1.79 yrs) participated in this study. Testing consisted of two trials (music [M]; no music [NM]] completed in a randomized order. Each participant performed the BP for a maximum number of repetitions using 70% one-repetition maximum for five sets. After a 10 min rest period, a 30 s Wingate anaerobic Test (WAT) was completed. During the M condition, there was a significant increase in total work (M: 16121.8±4287.3 kJ; NM: 15021.7±4370.6 kJ; P=0.024), relative peak power (M: 44.6±8.4 W; NM: 41.4±8.4 W; P=0.014), and the total number of bench press repetitions (M: 41.7±8.7 reps; NM: 38.3±8.1 reps; P=0.001). HR recovery following the WAT protocol was significantly quicker after the WAT protocol during the M condition (M: 256.2±54.5 sec.; NM 293.3±22.3 sec.; P=0.022). There was no significant condition as for gender interaction for any of the variables assessed. Listening to self-selected music improved exercise performance during the BP and the WAT. Music also hastened HR recovery following the WAT.

Endocrine Responses to Various 1 × 1 Small-Sided Games in Youth Soccer Players.

The aim of this study was to determine relationships between repeated 1 × 1 small-sided games (SSGs) (variable duration, constant work-to-rest ratio) and the concentration of steroid hormones and characteristic fatigue markers in youth soccer players. Eighteen young male soccer players were assigned at random to two experimental groups: E1—undertaking a six 30 s one-on-one SSGs with a 2 min rest period; and E2—playing six 45 s SSGs with a 3 min rest interval. Capillary blood was collected from the players at rest, after the last game, and 15 and 30 min after the exercise protocol. The variables assessed included serum cortisol (C), free testosterone (FT) and total testosterone (TT). An effect was observed between the measurement times (TT (F = 15.26, p ≤ 0.0001), FT (F = 6.86, p = 0.0006)). In terms of cortisol (C) levels, no interactions or effect between the studied groups were revealed, but an interaction was found (F = 4.01, p = 0.0126) and the effect appeared between the measurement times (F = 11.16, p ≤ 0.0001). The study results show that in all likelihood, longer rest intervals in repeated 30 s 1 × 1 SSGs can reduce catabolic reactions and hence the risk of overtraining in youth soccer players.

Effect of Lactobacillus plantarum TWK10 on Exercise Physiological Adaptation, Performance, and Body Composition in Healthy Humans.

Probiotics have been rapidly developed for health promotion, but clinical validation of the effects on exercise physiology has been limited. In a previous study, Lactobacillus plantarum TWK10 (TWK10), isolated from Taiwanese pickled cabbage as a probiotic, was demonstrated to improve exercise performance in an animal model. Thus, in the current study, we attempted to further validate the physiological function and benefits through clinical trials for the purpose of translational research. The study was designed as a double-blind placebo-controlled experiment. A total of 54 healthy participants (27 men and 27 women) aged 20–30 years without professional athletic training were enrolled and randomly allocated to the placebo, low (3 × 1010 colony forming units (CFU)), and high dose (9 × 1010 CFU) TWK10 administration groups (n = 18 per group, with equal sexes). The functional and physiological assessments were conducted by exhaustive treadmill exercise measurements (85% VO2max), and related biochemical indices were measured before and after six weeks of administration. Fatigue-associated indices, including lactic acid, blood ammonia, blood glucose, and creatinine kinase, were continuously monitored during 30 min of exercise and a 90 min rest period using fixed intensity exercise challenges (60% VO2max) to understand the physiological adaptation. The systemic inflammation and body compositions were also acquired and analyzed during the experimental process. The results showed that TWK10 significantly elevated the exercise performance in a dose-dependent manner and improved the fatigue-associated features correlated with better physiological adaptation. The change in body composition shifted in the healthy direction for TWK10 administration groups, especially for the high TWK10 dose group, which showed that body fat significantly decreased and muscle mass significantly increased. Taken together, our results suggest that TWK10 has the potential to be an ergogenic aid to improve aerobic endurance performance via physiological adaptation effects.

Active Preconditioning With Blood Flow Restriction or/and Systemic Hypoxic Exposure Does Not Improve Repeated Sprint Cycling Performance.

PurposeThe aim of this study was to evaluate the effects of active preconditioning techniques using blood flow restriction or/and systemic hypoxic exposure on repeated sprint cycling performance and oxygenation responses.MethodsParticipants were 17 men; 8 were cycle trained (T: 21 ± 6 h/week) and 9 were untrained but physically active (UT). Each participant completed 4 cycles of 5 min stages of cycling at 1.5 W⋅kg–1 in four conditions [Control; IPC (ischemic preconditioning) with partial blood flow restriction (60% of relative total occlusion pressure); HPC (hypoxic preconditioning) in normobaric systemic hypoxia (FIO2 13.6%); and HIPC (hypoxic and ischemic preconditioning combined)]. Following a 40 min rest period, a repeated sprint exercise (RSE: 8 × 10 s sprints; 20 s of recovery) was performed. Near-infrared spectroscopy parameters [for each sprint, change in deoxyhemoglobin (Δ[HHb]), total hemoglobin (Δ[tHb]), and tissue saturation index (ΔTSI%)] were measured.ResultsTrained participants achieved higher power outputs (+10–16%) than UT in all conditions, yet RSE performance did not differ between active preconditioning techniques in the two groups. All conditions induced similar sprint decrement scores during RSE in both T and UT (16 ± 2 vs. 23 ± 9% in CON; 17 ± 3 vs. 19 ± 6% in IPC; 18 ± 5 vs. 20 ± 10% in HPC; and 17 ± 3 vs. 21 ± 5% in HIPC, for T and UT, respectively). During the sprints, Δ[HHb] was larger after IPC than both HPC and CON in T (p < 0.001). The Δ[tHb] was greater after HPC than all other conditions in T, whereas IPC, HPC, and HIPC induced higher Δ[tHb] than CON in UT.ConclusionNone of the active preconditioning methods had an ergogenic effect on repeated sprint cycling performance, despite some specific hemodynamic responses (e.g., greater oxygen extraction and changes in blood volume), which were emphasized in the trained cyclists.

A Positioning Device for the Placement of Mice During Intranasal siRNA Delivery to the Central Nervous System.

Intranasal (IN) drug delivery to the brain has emerged as a promising method to bypass the blood-brain barrier (BBB) for the delivery of drugs into the central nervous system (CNS). Recent studies demonstrate the use of a peptide, RVG9R, incorporating the minimal receptor-binding domain of the Rabies virus glycoprotein, in eliciting the delivery of siRNA into neurons in the brain. In this protocol, the peptide-siRNA formulation is delivered intranasally with a pipette in the dominant hand, while the anesthetized mouse is restrained by the scruff with the nondominant hand in a "head down-and-forward position" to avoid drainage into the lung and stomach upon inhalation. This precise gripping of mice can be learned but is not easy and requires practice and skill to result in effective CNS uptake. Furthermore, the process is long-drawn, requiring about 45 min for the administration of a total volume of ~20-30 µL of solution in 1-2 µL droplet volumes per inhalation, with 3-4 min rest periods between each inhalation. The objective of this study is to disclose a mouse positioning device that enables the appropriate placement of mice for efficient IN administration of the peptide-siRNA formulation. Multiple features are incorporated into the design of the device, such as four or eight positioning chairs with adjustable height and tilt to restrain anesthetized mice in the head down-and-forward position, enabling easy visualization of the mice's nares and a built-in heating pad to maintain the mice's body temperatures during the procedure. Importantly, the ability to treat four or eight mice simultaneously with RVG9R-siRNA complexes in this manner enables studies on a much quicker time scale, for the testing of an IN therapeutic siRNA approach. In conclusion, this device allows for appropriate and controlled mouse head positioning for IN application of RVG9R-siRNA and other therapeutic molecules, such as nanoparticles or antibodies, for CNS delivery.

Inflammatory, Oxidative Stress, and Angiogenic Growth Factor Responses to Repeated-Sprint Exercise in Hypoxia.

The present study was designed to determine the effects of repeated-sprint exercise in moderate hypoxia on inflammatory, muscle damage, oxidative stress, and angiogenic growth factor responses among athletes. Ten male college track and field sprinters [mean ± standard error (SE): age, 20.9 ± 0.1 years; height, 175.7 ± 1.9 cm; body weight, 67.3 ± 2.0 kg] performed two exercise trials in either hypoxia [HYPO; fraction of inspired oxygen (FiO2), 14.5%] or normoxia (NOR; FiO2, 20.9%). The exercise consisted of three sets of 5 s × 6 s maximal sprints with 30 s rest periods between sprints and 10 min rest periods between sets. After completing the exercise, subjects remained in the chamber for 3 h under the prescribed oxygen concentration (hypoxia or normoxia). The average power output during exercise did not differ significantly between trials (p = 0.17). Blood lactate concentrations after exercise were significantly higher in the HYPO trial than in the NOR trial (p < 0.05). Plasma interleukin-6 concentrations increased significantly after exercise (p < 0.01), but there was no significant difference between the two trials (p = 0.07). Post-exercise plasma interleukin-1 receptor antagonist, serum myoglobin, serum lipid peroxidation, plasma vascular endothelial growth factor (VEGF), and urine 8-hydroxydeoxyguanosine concentrations did not differ significantly between the two trials (p > 0.05). In conclusion, exercise-induced inflammatory, muscle damage, oxidative stress, and VEGF responses following repeated-sprint exercise were not different between hypoxia and normoxia.

The effects of acute static and dynamic stretching on spring-mass leg stiffness

ObjectiveThis study investigated the effect of brief static and dynamic stretching on spring-mass leg stiffness in a vertical bilateral hopping task. Method38 men and 18 women were randomly assigned to either a natural (NAT; n = 27), or maximal (MAX; n = 29) hopping group. NAT bounced at their self-selected stiffness and MAX were instructed to bounce as stiffly as possible. Hopping was performed at 2.2 Hz on a force plate. After each of four treatment conditions (no stretch, 30 s stretch, multiple (4 × ) 30 s stretch, and dynamic stretch), subjects completed three × 30 s bouts (2 min rest periods) of hopping, in a counterbalanced crossover design. Stretches were performed on: gluteals, hamstrings, quadriceps and calves. Spring-mass leg stiffness was calculated as the ratio of peak vertical force to vertical displacement during ground contact. ResultsThe results revealed that men displayed greater leg stiffness than women (mean difference: 6.04 kN m−1; 95% likely range: 1.94–10.13 kN m−1), and that MAX produced higher stiffness values than NAT (mean difference: 10.93 kN m−1; 95% likely range: 6.84–15.03 kN m−1). Although there were no significant effects of treatment (p = 0.85) or time (p = 0.54) on leg stiffness, there was a significant treatment × time interaction (p = 0.015). Nevertheless, post hoc analyses were unable to identify where those differences were. ConclusionRelative to controls, the results of this study showed that brief static stretching or non task-specific dynamic stretching does not affect spring-mass leg stiffness during vertical bilateral hopping.

Does habitual endurance exercise protect endothelial function against acute exposure to oscillatory shear stress?

Introduction: Acute exposure to increases in oscillatory shear stress (increased retrograde shear stress and decreased mean shear stress) reduces flow-mediated dilation (FMD). This impairment may be mediated via increased oxidative stress. Habitual endurance exercise training results in increased antioxidant protection. However, it is currently unknown whether these adaptations protect against oscillatory shear stress-induced impairments in FMD.&#x0D; Purpose and Hypothesis: The purpose of this study is to determine whether lower limb endurance-trained athletes have protection against oscillatory shear stress-induced impairments in FMD compared to sedentary individuals. It is hypothesized that athletes will have a preserved FMD after an acute oscillatory shear stress intervention, compared to their sedentary counterparts.&#x0D; Methods: Healthy, young adult volunteers (18-29 years old) will be screened for physical activity (PA) through a physical activity recall questionnaire. 12 sedentary individuals (&lt;3h of structured PA/week) and 12 lower limb endurance athletes will be recruited to participate. All participants will complete a VO2 peak test to objectively measure cardiorespiratory fitness. Participants will visit the laboratory twice in the same week for vascular testing. Both 90-minute visits will begin with 45 minutes of supine rest, followed by a brachial artery FMD test before and after 30 minutes of either imposed oscillatory shear stress (forearm cuff inflated to 70 mmHg) or a 30 min rest period (control). &#x0D; Significance: This will be the first study to investigate whether endurance-trained athletes are resistant to oscillatory shear-stress induced impairments in endothelial function. This will provide insight into mechanism contributing to the vasoprotective effects of habitual endurance exercise.

Emotional intelligence and mood states impact on the stress response to a treadmill ultramarathon

ObjectivesParticipants of ultramarathon events experience a complex interaction of psychophysiological stressors. Therefore, the purpose of this study was to investigate the role of trait emotional intelligence (trait EI) on mood states and serum cortisol responses to a 80.5km treadmill ultramarathon. DesignTwelve participants completed an 80.5km time-trial on a motorised treadmill in the fastest possible time. MethodsParticipants’ trait EI was measured prior to the trial. A mood state questionnaire was completed prior (baseline: within two weeks of treadmill ultramarathon), immediately prior (pre: within 30min of commencing treadmill ultramarathon), at 40.25km (halfway: during standardised 10min rest period to allow for venous blood sampling) and on completion of 80.5km (post: immediately on completion of treadmill ultramarathon), along with serum cortisol concentrations measured at the same time points. ResultsCompletion time was 09:00:18±01:14:07 (hhmmss). Significant increase in serum cortisol and total mood disturbance (TMD) was observed throughout the treadmill ultramarathon (p<0.05). Participants with higher trait EI displayed a higher post cortisol concentration (p=0.01) with no change in TMD, compared to those with low trait EI who displayed a significant increase in TMD between pre and halfway (p=0.02). ConclusionsThe treadmill ultramarathon elicited a significant increase in serum cortisol concentration, which was significantly greater in those with a higher trait EI. Those individuals with higher trait EI were more effective at managing their mood, with little change total mood disturbance and perceived effort compared to those with lower trait EI.

Effects of knee extension with different speeds of movement on muscle and cerebral oxygenation.

BackgroundOne of the mechanisms responsible for enhancing muscular hypertrophy is the high metabolic stress associated with a reduced muscular oxygenation occurring during exercise, which can be achieved by reducing the speed of movement. Studies have tested that lowered muscle oxygenation artificially induced by an inflatable cuff, could provoke changes in prefrontal cortex oxygenation, hence, to central fatigue. It was hypothesized that (1) exercising with a slow speed of movement would result in greater increase in cerebral and greater decrease in muscle oxygenation compared with exercises of faster speed and (2) the amount of oxygenation increase in the ipsilateral prefrontal cortex would be lower than the contralateral one.MethodsAn ISS Imagent frequency domain near infrared spectroscopy (NIRS) system was used to quantify oxygenation changes in the vastus lateralis muscle and prefrontal cortex (contra- and ipsilateral) during unilateral resistance exercises with different speeds of movement to voluntary fatigue. After one maximal repetition (1RM) test, eight subjects performed three sets of unilateral knee extensions (∼50% of 1RM), separated by 2 min rest periods, following the pace of 1 s, 3 s and 5 s for both concentric and eccentric phases, in a random order, during separate sessions. The amount of change for NIRS parameters for muscle (ΔHb: deoxyhemoglobin, ΔHbO: oxyhemoglobin, ΔHbT: total hemoglobin, ΔStO2: oxygen saturation) were quantified and compared between conditions and sets by two-way ANOVA RM. Differences in NIRS parameters between contra- and ipsilateral (lobe) prefrontal cortex and conditions were tested.ResultsExercising with slow speed of movement was associated to larger muscle deoxygenation than normal speed of movement, as revealed by significant interaction (set × condition) for ΔHb (p = 0.01), and by significant main effects of condition for ΔHbO (p = 0.007) and ΔStO2 (p = 0.016). With regards to the prefrontal cortex, contralateral lobe showed larger oxygenation increase than the ipsilateral one for ΔHb, ΔHbO, ΔHbT, ΔStO2 in each set (main effect of lobe: p < 0.05). Main effects of condition were significant only in set1 for all the parameters, and significant interaction lobe × condition was found only for ΔHb in set1 (p < 0.05).DiscussionThese findings provided evidence that speed of movement influences the amount of muscle oxygenation. Since the lack of oxygen in muscle is associated to increased metabolic stress, manipulating the speed of movement may be useful in planning resistance-training programs. Moreover, consistent oxygenation increases in both right and left prefrontal lobes were found, suggesting a complementary interaction between the ipsi- and contralateral prefrontal cortex, which also seems related to fatigue.

The Effect of Exercise Intensity on Gastric Emptying Rate, Appetite and Gut Derived Hormone Responses after Consuming a Standardised Semi-Solid Meal in Healthy Males.

This study investigated the acute circulating gut hormone, appetite and gastric emptying rate responses to a semi-solid meal following exercise at different intensities. Twelve men completed three trials in a randomised-crossover design, consisting of continuous cycling at 70% O2Peak (HIGH), 40% O2Peak (LOW) or rest (CONTROL). Baseline samples were collected after an overnight fast before undertaking the 60 min exercise or rest period, followed by 30 min rest before consumption of a standardised semi-solid meal (~242 kcal). During the 2 h postprandial period, gastric emptying rate of the meal was examined using the 13C-breath test method, appetite was measured using visual analogue scales, and serum concentrations of acylated ghrelin, pancreatic polypeptide, peptide YY, glucagon-like peptide-1, insulin, glucose, triglycerides, total cholesterol and non-esterified fatty acids were assessed. Subjective appetite response was not different between trials (p > 0.05). Half emptying time of the meal was 89 ± 13, 82 ± 8 and 94 ± 31 min on CONTROL, LOW and HIGH, respectively (p = 0.247). In healthy un-trained adult males, responses to exercise at intensities of 70% and 40% O2Peak did not differ to a non-exercise control for measurements of subsequent gastric emptying, circulating gut hormone response or appetite. These results suggest that exercise intensity has little effect on post-exercise appetite response to a semi-solid meal.

Can grip strength be used as a surrogate marker to monitor recovery from shoulder fatigue?

Muscular fatigue impacts on normal shoulder function, which is particularly pertinent to throwing athletes. This study aimed to investigate the relationship between grip strength and shoulder muscle fatigue to evaluate the role of grip strength as a surrogate measure for upper limb performance. Twenty healthy participants were recruited. EMG was recorded from 15 shoulder muscles during different fatiguing contractions: an initial baseline recording (Fat-Baseline); after a shoulder exhausting exercise regime (Fat-Exhaustion); and after a 10 min rest period (Fat-Recovery). Grip strength was similarly measured in the same conditions. Grip strength differed significantly across the testing scenarios (p = 0.012–<0.001). Greater fatigue was seen in anterior deltoid, middle deltoid, posterior deltoid and supraspinatus in the Fat-Exhaustion contraction as compared to the Fat-Baseline contraction (p = <0.001–0.043). Greater fatigue was seen during the Fat-Recovery contraction for the trapezius, serratus anterior and biceps brachii as compared to the Fat-Exhaustion contraction (p = 0.008–0.038). Grip strength decreased following an exhausting exercise protocol but recovered to baseline following a rest period. Conversely, EMG indices of fatigue did not recover. Additional fatigue was seen reflecting a reorganisation of movement strategy. Therefore, susceptibility to injury still exists if grip strength alone is used as a barometer of upper limb performance.

Immediate effects of talus-stabilizing taping on balance and gait parameters in patients with chronic stroke: a cross-sectional study

ABSTRACTBackground: Talus-stabilizing taping (TST) may improve ankle range of motion and gait performance by providing a posterior–inferior talar glide in a closed-chain dorsiflexion position.Objectives: This study aimed to investigate the immediate effects of TST on balance and gait parameters in patients with chronic stroke.Methods: Twenty post-stroke patients participated in this study. Each participant performed tests under three conditions (TST, barefoot, and conventional ankle-foot orthosis [AFO]), in random order. Before testing, the patients walked for 10 min under the three conditions, followed by a 5 min rest period. The outcome measures were static balance ability (SBA), timed up-and-go (TUG) test results, and gait parameters evaluated using a 6-m-long gait mat. One-way repeated measures analysis of variance was used to determine the difference in balance and gait parameters under the three conditions.Results: SBA more significantly improved in the TST condition than in the barefoot condition. SBA more significantly improved in the conventional AFO condition than in the barefoot condition. The TUG test results more significantly improved in the TST condition than in the conventional AFO and barefoot conditions. Walking speed, cadence, and affected side and unaffected side step and stride lengths more significantly improved in the TST condition than in the conventional AFO and barefoot conditions.Conclusions: This study used a cross-sectional method and demonstrated that TST improves SBA, TUG, gait speed, cadence, step length, and stride length in patients with chronic stroke.

Muscle Oxygenation &amp; Systemic Metabolic Responses during Maximal Sprint Exercise in Hypoxia among Athletes

The influence of maximal sprint exercise in moderate hypoxia on muscle oxygenation and systemic metabolic responses has not been fully elucidated. PURPOSE: The purpose of the present study was to determine the effects of maximal sprint exercise in moderate hypoxia on muscle oxygenation, systemic oxygen uptake and power output among competitive athletes. METHODS: Seven sprinters (height; 176.1 ± 2.2 cm, body weight; 67.8 ± 3.4 kg, BMI; 22.6 ± 0.7 kg/m2) participated. They performed two trials under either hypoxic (HYP, FiO2: 14.5%, a simulated altitude of 3000m) or normoxic (NOR, FiO2: 20.9%) conditions in a randomized, with a single-blind and crossover design. The exercise in each trial consisted of three consecutive sets of 20-s maximal sprints with a 5 min rest period between sets. Time-course changes in percutaneous oxygen saturation (SpO2), power output during exercise, blood lactate, glucose concentrations, and muscle oxygenation [oxy-hemoglobin (Hb), deoxy-Hb, total-Hb], and respiratory variables were evaluated. RESULTS: A significant main effect of number of set was observed for mean power output during exercise (P<0.01). However, no significant interaction (trial × number of set, P=0.76) or main effect of trial (P=0.66) for mean power output was observed. There were significant main effects of trial (P<0.01) and time (P<0.01) for blood lactate concentration, and post-exercise blood lactate concentrations were significantly higher in the HYP (22.8 ± 0.6 mmol/L) than in the NOR (20.0 ± 0.7 mmol/L, P<0.05). Both trials showed significant increases in deoxy-Hb and total-Hb during the exercise (main effect of time, P<0.01). However, deoxy-Hb and total-Hb tended to be higher in the HYP during the latter sets of sprint. Accumulated VO2 during exercise was significantly lower in the HYP (1419 ± 76 ml) than in the NOR (1973 ± 120 ml, P<0.01), whereas accumulated VCO2 was not significantly different between the trials (main effect of trial, P=0.65). CONCLUSION: No apparent difference in muscle oxygenation kinetics during maximal sprint exercise was found between hypoxic and normoxic conditions. However, exercise-induced elevations of muscle deoxygenation (deoxy-Hb) tended to be augmented under hypoxic condition.

Movement Variability and Accuracy Within the Temporal and Spatial Domains When Provided a Vibrotactile Stimulus

Different means of informing body movements can include visual, auditory, and vibrotactile (VT) stimuli. Each method may guide movements within the temporal (TEMP) and spatial (SPAT) domains in varying ways. As VT stimuli has become more accessible, it is important to understand how users interpret this method of instruction to promote patterned movements. PURPOSE: Determine the effects of VT stimulus pattern speed on TEMP and SPAT movement variability (VAR) and accuracy (ACC). METHODS: Sixteen young healthy subjects were recruited. Participants completed a continuous wrist flexion and extension activity. The task involved matching wrist motion with two different VT pattern speeds (FAST, SLOW) provided via motors attached to the forearm. An electrogoniometer captured wrist movement. Five 20s trials with 2min rest periods were completed for the two speeds. Flexion/extension movements were combined for further analysis. Absolute (STDEV) and relative (CV) VAR, and ACC (mean absolute error) for TEMP and SPAT domains were calculated within individuals. 5x2 linear mixed models accounting for repeated measures compared the variables across pattern speeds and trial numbers. Post-hoc Tukey HSDs identified differences for trial effects. RESULTS: No significant interactions were found in either domain. Significant pattern speed effects were observed in the TEMP domain for VAR (STDEV: FAST 0.07s, SLOW 0.13s, p < .05; CV: FAST 12.9%, SLOW 16.8%, p < .05), and ACC (FAST 0.05s, SLOW 0.10s, p < .05). VAR in the both domains and TEMP ACC changed significantly over the 5 trials (all, p < .05; ACC SPAT, p > .05). Post-hoc tests revealed trial 1 to be different from all subsequent trials for TEMP and SPAT VAR (STDEV TEMP: #1: 0.15s, #5: 0.08s, p < .05; STDEV SPAT: #1: 7.7deg, #5: 4.7deg, p < .05; CV TEMP: #1: 20.8%, #5: 13.2%, p < .05; CV SPAT: #1: 11.9%, #5: 5.9%, p < .05), and ACC TEMP (#1: 0.11s, #5: 0.07s, p < .05). CONCLUSIONS: VT stimulus appears capable of producing a desired continuous wrist movement at multiple pattern speeds. TEMP VAR was lower and TEMP ACC was higher for the FAST speed, while SPAT measures did not differ between speeds. Lower TEMP and SPAT VAR, and higher TEMP ACC were observed by trial 2, with improved performance maintained in the remaining trials. A lack of change in SPAT ACC may reflect limited SPAT guidance provided to subjects.

The influence of isometric exercise on endogenous pain modulation: comparing exercise-induced hypoalgesia and offset analgesia in young, active adults.

Background and aims Impairment of endogenous analgesia has been associated with the development, maintenance and persistence of pain. Endogenous analgesia can be evaluated using exercise-induced hypoalgesia (EIH) and offset analgesia (OffA) paradigms, which measure temporal filtering of sensory information. It is not clear if these paradigms are underpinned by common mechanisms, as EIH and OffA have not previously been directly compared. A further understanding of the processes responsible for these clinically relevant phenomena may have future diagnostic and therapeutic utility in management of individuals with persistent pain conditions. The primary aim of this study was to investigate if there is a correlation between the magnitudes of EIH and OffA. The secondary aim of the study was to examine whether exercise influences OffA. Methods Thirty-six healthy, pain-free participants were recruited. EIH was evaluated using pressure pain thresholds (PPT) and pain ratings to suprathreshold pressure stimuli over tibialis anterior and the cervical spine. OffA evaluation utilised a three-step protocol, whereby individualised heat pain thermal stimuli [Numerical Rating Scale (NRS)=50/100] were applied (T1), before increasing 1 °C (T2), followed by 1 °C reduction (T3). The magnitude of OffA was calculated as the percentage reduction in the NRS from T2 to T3. PPT/suprathreshold pain ratings and OffA measures were recorded, before and after 5 min of isometric quadriceps exercise performed at 20-25% maximum voluntary contraction (MVC); and following a 15 min rest period. Data were analysed using repeated measures (RM) ANCOVA and correlational analyses. Results There was no correlation between EIH measures (PPTs or pain ratings to suprathreshold pressure stimuli over tibialis anterior or the cervical spine) and OffA (p>0.11 for all). OffA was induced and not modulated by exercise (p=0.28). Conclusions Five minutes of 20-25% MVC lower limb isometric exercise provided non-pharmacological pain modulation in young, active adults. Magnitude of EIH was not correlated with that of OffA, and exercise did not influence magnitude of OffA. Implications These results suggest that in young, pain-free individuals, separate testing of these two paradigms is required to comprehensively evaluate efficacy of endogenous analgesia. If these results are replicated in patient populations, alternative or complementary methods to exercise interventions may be required to modulate impaired OffA.

Enhanced nasal drug delivery efficiency by increasing mechanical loading using hypergravity

Nasal route drug administration for local and systemic delivery of many therapeutics has received attention because the nasal cavity is highly vascularized and provides a large surface area for drug absorption. However, nasal mucosa exhibits limited permeability to polar molecules. In this study, we developed a novel method for improving absorption efficiency of polar drugs by applying hypergravity. RPMI 2650 cells and primary human nasal epithelial cells were exposed three times to a 20 min hypergravitational condition (10 × g) with a 20 min rest period after each exposure. The applied hypergravity induced a decrease in transepithelial electrical resistance without significant loss of cellular metabolic activity, and cellular permeability of fluorescein sodium salt (MW 376 Da; NaFI) and FITC-labeled dextran (average MW 4,000 Da; FD-4) increased by 19% and 16%, respectively. Immunostaining and RT-qPCR results demonstrated that hypergravity conditions affected cytoskeletal structures and tight junctions, leading to weakening of the cell barrier function and increasing the cellular permeability of polar molecules. Our results indicate that hypergravity could be used as a new strategy for enhancing the efficiency of drug absorption via the nasal route.

Endocrine responses following exhaustive strength exercise with and without the use of protein and protein-carbohydrate supplements.

The aim of this study was to determine the effect of carbohydrate-protein supplementation with whey protein (CHO-PROw) after resistance training, and casein protein (PROc) before bedtime on the concentration of growth hormone (GH), insulin (I) and insulin-like growth factor (IGF-1), as well as serum creatine kinase (CK) activity. Twelve strength trained male subjects (age: 25.8 ± 4.7 years; training experience 6.1 ± 0.79 years; body mass 75.9 ± 2.7 kg; body height 171.8 ± 13.3 cm) were recruited for the study. They were randomly divided into an experimental group (group E, n = 6) and a control group (group C, n = 6). All study participants completed full barbell squats with a constant external load of 90% one-repetition maximum (1RM) and a volume of 12 sets. In each set three repetitions were performed with 3 min rest periods after each set. Immediately after the exercise protocol, the subjects from the experimental group received a carbohydrate-protein complex (CHO-PROw) with a dose of 0.5 g/kg of body mass, while before bedtime they ingested a protein supplement (PROc) consisting of 90% casein protein with a dose of 0.3 g/kg of body weight The results indicate that a ignificant increase in GH concentration occurred in the experimental group between the pre-exercise level and after 24 h of recovery (p<0.01), as well as between 1 h and 24 hours of recovery (p<0.01). Significantly higher levels of GH were also found between the control group and the experimental group 24 hours after exercise (p<0.01). The results showed significantly higher levels of IGF-1 in the experimental than in the control group after 24 hours of recovery (p<0.05). In the case of insulin, no significant differences were observed when comparing levels before exercise, after exercise, after 1 hour of recovery and after 24 hours of recovery. The CHO-PROw and the PROc supplements did not reduce post-exercise muscle membrane damage as evidenced by serum CK activity. The intake of these supplements after high-intensity resistance exercise caused an increase in GH and IGF-1 concentration, which could stimulate muscle hypertrophy and inhibit proteolysis.

Optimization of micro-scale extension tests for wheat dough and wet gluten

Micro-scale extension tests to determine the viscoelastic properties of wheat dough and wet gluten based on 10 g of flour each are useful methods to predict baking performance, but there is no official standard method. The experimental procedure was optimized by varying rest periods and test speeds and the results were evaluated considering repeatability, discrimination of different samples and duration of analysis. In both tests, dough was prepared by mixing to the respective optimum consistency followed by a 15 min rest period at 22 °C and measurement at a test speed of 3.3 mm/s for dough. For wet gluten, the subsequent steps involved removal of starch by washing, centrifugation of the gluten strands (3060 × g, 10 min, 22 °C), resting for 30 min at 22 °C and measurement using the same test speed (3.3 mm/s) with the SMS/Kieffer Dough and Gluten Extensibility Rig fitted to a texture analyzer. Correlation analyses revealed, inter alia, that the maximum resistance to extension and the area under the curve of wet gluten extension tests were suitable to predict micro-rapid-mix test loaf volumes. In combination with the micro-scale extension test for rehydrated vital wheat gluten, these methods are deemed suitable for international validation.