Psychophysiological Responses During a Cycling Test to Exhaustion While Wearing the Elevation Training Mask.

ABSTRACT: López-Pérez, ME, Romero-Arenas, S, Colomer-Poveda, D, Keller, M, and Márquez, G. Psychophysiological responses during a cycling test to exhaustion while wearing the elevation training mask. J Strength Cond Res 36(5): 1282-1289, 2022-The aim of this study was to investigate the psychophysiological effects of wearing the elevation training mask (ETM). Twelve men performed time-to-exhaustion (TTE) tests at 75% of peak power output with and without wearing the ETM. Heart rate (HR), rating of perceived exertion (RPE), breathing discomfort (BD), and oxygen saturation (SpO2) were measured during the TTE. Prefrontal cortex (PFC) and vastus lateralis oxygenated, deoxygenated, and total hemoglobin were monitored using near-infrared spectroscopy. At the end of each test, blood lactate values (La-) were collected, and subjects completed the Beck Anxiety Inventory (BAI). The mask caused a reduction in the TTE (-37.7%; p < 0.001) and in the SpO2 (-2%; p < 0.001). Beck Anxiety Inventory scores were negatively correlated with the changes observed in the TTE (r = -0.77; p < 0.01). La-, HR, and muscle oxygenation displayed similar results across conditions. In conjunction with an increased hemodynamic response in the PFC, subjects reported higher RPE and BD values in the ETM condition (p < 0.01). Finally, BAI scores were negatively correlated with the changes observed in the TTE (r = -0.77; p < 0.01). This study suggests that wearing the ETM induces psychophysiological alterations affecting the exercise tolerance and limiting the performance.

Training load but not fatigue affects cross-education of maximal voluntary force.

The purpose of this study was to determine the effects of training load (25% vs. 75% of one repetition maximum [1RM]) and fatigue (failure vs. non-failure) during four weeks of unilateral knee extension resistance training (RT) on maximal voluntary force in the trained and the untrained knee extensors. Healthy young adults (n = 42) were randomly assigned to control (CON, n = 9, 24 ± 4.3 years), low-load RT to failure (LLF, n = 11, 21 ± 1.3 years, three sets to failure at 25% of 1RM), high-load RT to failure (HLF, n = 11, 21 ± 1.4 years, three sets to failure at 75% of 1RM), and high-load RT without failure (HLNF, n = 11, 22 ± 1.5 years, six sets of five repetitions at 75% of 1RM) groups. Before and after the four weeks of training, 1RM, maximal voluntary isometric force, and corticospinal excitability (CSE) were measured. 1RM in the trained (20%, d = 0.70, 15%, d = 0.61) and the untrained knee extensors (5%, d = 0.27, 6%, d = 0.26) increased only in the HLF and HLNF groups, respectively. MVIC force increased only in the trained leg of the HLF (5%, d = 0.35) and HLNF groups (12%, d = 0.67). CSE decreased in the VL of both legs in the HLNF group (-19%, d = 0.44) and no changes occurred in the RF. In conclusion, high- but not low-load RT improves maximal voluntary force in the trained and the untrained knee extensors and fatigue did not further enhance these adaptations. Voluntary force improvements were unrelated to CSE changes in both legs.

Oxygenation Responses While Wearing the Elevation Training Mask During an Incremental Cycling Test.

ABSTRACT: Romero-Arenas, S, López-Pérez, E, Colomer-Poveda, D, and Márquez, G. Oxygenation responses while wearing the elevation training mask during an incremental cycling test. J Strength Cond Res 35(7): 1897-1904, 2021-The Elevation Training Mask 2.0 (ETM) is a commercial training mask that purportedly simulates altitude training, although their effects have not been conclusively demonstrated. Therefore, the purpose of this study was to evaluate the influence of wearing the ETM on muscle and brain oxygenation responses during a maximal incremental cycling test, as well as the influence of this device on the heart rate (HR) response, perception of effort (rating of perceived exertion [RPE]), arterial oxygen saturation (SaO2), blood lactate (La+), and performance (POpeak). Fourteen active males completed an incremental cycling test to volitional exhaustion in 2 separate and counterbalanced conditions, wearing the mask set at 9,000 feet (i.e., 2743 m) and a control condition (CTR, without ETM). During the trial, muscle and cerebral oxygenation were monitored continuously using near-infrared spectroscopy. Heart rate, RPE, and SaO2 were also recorded from the beginning of the test until the volitional exhaustion. La+ was measured at the end of each test. Wearing the ETM significantly reduced the POpeak by -6.9 ± 6.6% (p = 0.002) and this was accompanied by lower La+ values (-12.8 ± 21.6%; p = 0.027). SaO2 was also significantly lower at maximal intensity in comparison with the CTR condition (-1.5 ± 0.3%; p = 0.028). However, both HR and RPE showed a similar trend during both sessions, as well as muscle oxygenation. Nevertheless, the mask caused an increase in brain oxygenation compared with the CTR condition (p < 0.05). In conclusion, our findings suggest that wearing the ETM causes a pronounced increase in O2Hb and tHb in the frontoparietal cortex without any change in the muscle oxygenation.

Transcranial Direct Current Stimulation Does Not Improve Countermovement Jump Performance in Young Healthy Men.

ABSTRACT: Romero-Arenas, S, Calderón-Nadal, G, Alix-Fages, C, Jerez-Martínez, A, Colomer-Poveda, D, and Márquez, G. Transcranial direct current stimulation does not improve countermovement jump performance in young healthy men. J Strength Cond Res 35(10): 2918-2921, 2021-The main purpose of this study was to report the effects of transcranial direct current stimulation (tDCS) on countermovement jump (CMJ) performance in young healthy men. Seventeen healthy male subjects volunteered for the study (age: 22.4 ± 2.6 years; body mass: 71.8 ± 8.7 kg; height: 174.6 ± 5.9 cm; and CMJ height: 36.8 ± 6.3 cm). After a familiarization session, subjects underwent 3 experimental conditions, 7 days apart, in a randomized, double-blinded crossover design: anodal, cathodal, and sham tDCS. The stimulation was applied over the dorsolateral prefrontal cortex for 15 minutes. During experimental sessions, subjects completed a warm-up and 3 CMJ trials separated by 1 minute before and after each of the 3 experimental conditions. Countermovement jump height and muscular peak power were extracted from the best CMJ in each moment. A 2-way repeated-measures analysis of variance with time and condition as factors were performed for CMJ height and muscular peak power. Effect size analysis was conducted using Cohen's d coefficient. The analysis did not show either significant main effects or interactions for both time and condition factors in the CMJ performance (p > 0.05). Furthermore, effect size was trivial for all conditions (d: 0.01-0.14) in CMJ height and muscular peak power. These findings suggest that tDCS may not be a valuable tool to improve vertical jump performance.

Training intensity-dependent increases in corticospinal but not intracortical excitability after acute strength training.

The purpose of this study was to determine whether the increases in corticospinal excitability (CSE) observed after one session of unilateral isometric strength training (ST) are related to changes in intracortical excitability measured by magnetic brain stimulation (TMS) in the trained and the contralateral untrained biceps brachii (BB) and whether such changes scale with training intensity. On three separate days, 15 healthy young men performed one ST session of 12 sets of eight isometric contractions of the right elbow flexors at 0% (control session), 25%, or 75% of the maximal voluntary contraction (MVC) in a random order. Before and after each session separated at least by 1 week, motor evoked potential (MEP) amplitude, short-interval intracortical inhibition (SICI), contralateral silent period (SP), and intracortical facilitation (ICF) generated by TMS were measured in the trained and the untrained BBs. Compared with baseline, MEPs recorded from the trained BB increased by ~47% after training at 75% of MVC (P < .05) but not after training at 0% (~4%) or 25% MVC (~5%, both P > .05). MEPs in the untrained BB and SICI, SP, and ICF in either BB did not change. Therefore, acute high-intensity but not low-intensity unilateral isometric ST increases CSE in the trained BB without modifications in intracortical inhibition or facilitation. Thus, increases in corticospinal neurons or α-α-motoneuron excitability could underlie the increases in CSE. Regardless of contraction intensity, acute isometric ST did not modify the excitability of the ipsilateral primary motor cortex measured by TMS.

Anodal transcranial direct current stimulation enhances strength training volume but not the force-velocity profile.

PURPOSE: This study aimed to explore the acute effect of transcranial direct current stimulation (tDCS) on the force-velocity relationship, strength training volume, movement velocity, and ratings of perceived exertion. METHODS: Fourteen healthy men (age 22.8 ± 3.0 years) were randomly stimulated over the dorsolateral prefrontal cortex with either ANODAL, CATHODAL or SHAM tDCS for 15 min at 2 mA. The one-repetition maximum (1RM) and force-velocity relationship parameters were evaluated during the bench press exercise before and after receiving the tDCS. Subsequently, participants completed a resistance training session consisting of sets of five repetitions with 1 min of inter-set rest against the 75%1RM until failure. RESULTS: No significant changes were observed in the 1RM or in the force-velocity relationship parameters (p ≥ 0.377). The number of repetitions was higher for the ANODAL compared to the CATHODAL (p = 0.025; ES = 0.37) and SHAM (p = 0.009; ES = 0.47) conditions. The reductions of movement velocity across sets were lower for the ANODAL than for the CATHODAL and SHAM condition (p = 0.014). RPE values were lower for the ANODAL compared to the CATHODAL (p = 0.119; ES = 0.33) and SHAM (p = 0.150; ES = 0.44) conditions. No significant differences between the CATHODAL and SHAM conditions were observed for any variable. CONCLUSION: The application of ANODAL tDCS before a resistance training session increased training volume, enabled the maintenance of higher movement velocities, and reduced RPE values. These results suggest that tDCS could be an effective method to enhance resistance-training performance.

Neuromuscular and Cardiovascular Adaptations in Response to High-Intensity Interval Power Training.

Romero-Arenas, S, Ruiz, R, Vera-Ibáñez, A, Colomer-Poveda, D, Guadalupe-Grau, A, and Márquez, G. Neuromuscular and cardiovascular adaptations in response to high-intensity interval power training. J Strength Cond Res 32(1): 130-138, 2018-The aim of this study was to determine the efficacy of a high-intensity power training (HIPT) program, and to compare the effects of HIPT to traditional power training (TPT) on the aerobic and power performance. For this purpose, 29 healthy men (23.1 ± 2.7 years) were recruited and randomly distributed into 3 different groups. One group performed TPT (n = 10), the second group performed power training organized as a circuit (HIPT; n = 10), and the third group served as control group (CG; n = 9). Training consisted of weightlifting thrice per week for 6 weeks. The TPT subjects performed 3 to 5 sets of each exercises with interset rest of 90 seconds, and HIPT subjects executed the training in a short circuit (15 seconds of rest between exercises). To know the effects in aerobic performance, maximal aerobic speed (MAS) was measured. To identify the effects on power performance, subjects performed a Wingate test, a countermovement jump (CMJ) test, and a power-load curve in bench press. The main results showed that after both power training protocols, subjects increased significantly (p ≤ 0.05) the power production during the Wingate Test, the height and power reached during the CMJ test, and the peak power produced during the power-load curve. However, only the HIPT group improved significantly MAS (p ≤ 0.05). There were no changes in any variables in CG. Hence, our results suggest that HIPT may be as effective as TPT for improving power performance in young adults. In addition, only HIPT elicited improvements in MAS.

Peripheral and central fatigue after high intensity resistance circuit training.

INTRODUCTION: The aim of this study was to investigate the effects of high intensity resistance circuit (HIRC) and traditional strength training (TST) on neuromuscular fatigue and metabolic responses. METHODS: Twelve trained young subjects performed HIRC and TST in a counterbalanced order with 1 week rest in-between. The amount of workload and the inter-set time for each local muscle group were matched (180 s), however, the time between successive exercises differed. The twitch interpolation technique was used to test neuromuscular function of the knee extensor muscles. Blood lactate concentration was used to evaluate metabolic responses. RESULTS: Maximum voluntary contraction and resting potentiated twitch amplitude (Qtw ) were significantly reduced after HIRC, but there were not changes after TST, while reductions in voluntary activation were similar. Lactate concentration increased significantly more after HIRC. CONCLUSIONS: The higher lactate concentration after HIRC probably impaired excitation-contraction coupling, indicating larger peripheral fatigue than after TST. Muscle Nerve 56: 152-159, 2017.

Effects of 4 weeks of low-load unilateral resistance training, with and without blood flow restriction, on strength, thickness, V wave, and H reflex of the soleus muscle in men.

PURPOSE: To test the effects of 4 weeks of unilateral low-load resistance training (LLRT), with and without blood flow restriction (BFR), on maximal voluntary contraction (MVC), muscle thickness, volitional wave (V wave), and Hoffmann reflex (H reflex) of the soleus muscle. METHODS: Twenty-two males were randomly distributed into three groups: a control group (CTR; n = 8); a low-load blood flow restriction resistance training group (BFR-LLRT; n = 7), who were an inflatable cuff to occlude blood flow; and a low-load resistance training group without blood flow restriction (LLRT; n = 7). The training consisted of four sets of unilateral isometric LLRT (25% of MVC) three times a week over 4 weeks. RESULTS: MVC increased 33% (P < 0.001) and 22% (P < 0.01) in the trained leg of both BFR-LLRT and LLRT groups, respectively. The soleus thickness increased 9.5% (P < 0.001) and 6.5% (P < 0.01) in the trained leg of both BFR-LLRT and LLRT groups, respectively. However, neither MVC nor thickness changed in either of the legs tested in the CTR group (MVC -1 and -5%, and muscle thickness 1.9 and 1.2%, for the control and trained leg, respectively). Moreover, V wave and H reflex did not change significantly in all the groups studied (Vwave/M wave ratio -7.9 and -2.6%, and H max/M max ratio -3.8 and -4%, for the control and trained leg, respectively). CONCLUSIONS: Collectively, the present data suggest that in spite of the changes occurring in soleus strength and thickness, 4 weeks of low-load resistance training, with or without BFR, does not cause any change in neural drive or motoneuronal excitability.

Effect of a whole-body vibration training modifying the training frequency of workouts per week in active adults.

The aim of this study was to evaluate the effects of whole-body vibration by varying the training frequency (2 or 3 sessions per week) on the development of strength, body composition, and mechanical power. Forty-one (32 men and 9 women) recreationally active subjects (21.4 ± 3.0 years old; 172.6 ± 10.9 cm; 70.9 ± 12.3 kg) took part in the study divided in 2 experimental groups (G2 = 2 sessions per week, G3 = 3 sessions per week) and a control group (CG). The frequency of vibration (50 Hz), amplitude (4 mm), time of work (60 seconds), and time of rest (60 seconds) were constant for G2 and G3 groups. Maximum isokinetic strength, body composition, and performance in vertical jumps were evaluated at the beginning and the end of the training cycle. A statistically significant increase of isokinetic strength was observed in G2 and G3 at angular velocities of 60, 180, and 270°·s. Total fat-free mass was statistically significantly increased in G2 (0.9 ± 1.0 kg) and G3 (1.5 ± 0.7 kg). In addition, statistically significant differences between G3 and CG (1.04 ± 1.7%) (p = 0.05) were found. There were no statistically significant changes in the total fat mass, fat percentage, bone mineral content, and bone mineral density in any of the groups. Both vibration training schedules produced statistically significant improvements in isokinetic strength. The vibration magnitude of the study presented an adaptation stimulus for muscle hypertrophy. The vibration training used in this study may be valid for athletes to develop both strength and hypertrophy of the lower limbs.

Effects of different amplitudes (high vs. low) of whole-body vibration training in active adults.

The aim of this study was to evaluate the effects of two different amplitudes of whole-body vibrations on the development of strength, mechanical power of the lower limb, and body composition. Thirty-eight recreationally active participants took part in the study. Participants were divided in two experimental groups (low amplitude group [GL] = 2 mm; high amplitude group [GH] = 4 mm) and a control group. The experimental groups performed an incremental vibratory training, 2 days per week during 6 weeks. The frequency of vibration (50 Hz), time of work (60 seconds), and time of rest (60 seconds) were constant for GL and GH groups. All the participants were on the platform in a static semi-squat position. Maximum isokinetic strength, body composition, and performance in vertical jumps (squat and countermovement jumps) were evaluated at the beginning and at the end of the training cycle. A significant increase of isokinetic strength was observed in GL and GH at angular velocities of 60°.s(-1), 180°.s(-1) and 270°.s(-1). Total lean mass was significantly increased in GH (0.9 ± 1.0 kg). There were no significant changes in the total fat mass in any of the groups. Significant changes were not observed in different variables (height, peak power, and rate of force development) derived from the vertical jumps for any of the groups submitted to study. The vibration training, whatever the amplitude, produced significant improvements in isokinetic strength. However, high vibration amplitude training presents better adaptations for hypertrophy than the training with low vibration amplitude. In this sense, GH would be a better training if the practitioners want to develop both strength and hypertrophy of the lower limbs.

Adapted sailing teaching methodology using vsail-trainer simulator as rehabilitation therapy. A feasibility study.

CONTEXT: Sailing is a sport that can help in the rehabilitation of Spinal Cord Injury (SCI) patients and improve their quality of life. Teaching methodology in sailing has always been considered as complex, due to the great amount of uncertainty that this sport has. PURPOSE: To design a protocol for teaching adapted sailing in a simulated situation for people with SCI and to know the effect of the teaching protocol on learning, effort perception and heart rate. METHOD: Six adults were patients recruited at the National Hospital of Paraplegics of Toledo (Spain), aged between 31 and 54 years, who have passed the early subacute phase. Each subject underwent semi-immersive virtual reality sailing therapy for 40 min per session three times per week for six weeks, 18 sessions. A simulated adapted sailing initiation program VSail-Trainer® was used for the simulator therapy. During this session, the basic notions of sailing, wind direction, sheet trimming and control of the boat on different courses were explained. The variables assessed were: sailing learning, heart rate and effort perception. RESULTS: The comparison of performance variables between pretest and posttest resulted differences in boat speed, heel and Velocity Made Good (VMG). These improvements in the performance variables are also reflected in the average times taken by the subjects to complete the regatta. CONCLUSION: The methodology used in this study can be used as a guide for learning the activity by new SCI patients in rehabilitation who want to get into sailing sport.

Assessment of Intercostal Muscle Near-Infrared Spectroscopy for Estimating Respiratory Compensation Point in Trained Endurance Athletes.

This study aimed to assess the reliability and validity of estimating the respiratory compensation point (RCP) in trained endurance athletes by analyzing intercostal muscles' NIRS-derived tissue oxygenation dynamics. Seventeen experienced trail runners underwent an incremental treadmill protocol on two separate occasions, with a 7-day gap between assessments. Gas exchange and muscle oxygenation data were collected, and the oxygen saturation breakpoint (SmO2BP) measured in the intercostal muscles was compared to the RCP, which was identified by the increase in the VE/V.CO2 slope and the point at which the PetCO2 started to decrease. No statistically significant differences were observed between the two methods for any of the variables analyzed. Bland-Altman analysis showed significant agreement between the NIRS and gas analyzer methods for speed (r = 0.96, p < 0.05), HR (r = 0.98, p < 0.05), V.O2 relative to body mass (r = 0.99, p < 0.05), and %SmO2 (r = 0.98, p < 0.05). The interclass correlation coefficient values showed moderate to good reliability (0.60 to 0.86), and test-retest analysis revealed mean differences within the confidence intervals for all variables. These findings suggest that the SmO2BP measured using a portable NIRS device in the intercostal muscles is a reliable and valid tool for estimating the RCP for experienced trail runners and might be useful for coaches and athletes to monitor endurance training.

Does Heavy-Resistance Training Improve Mobility and Perception of Quality of Life in Older Women?

Regular physical exercise has shown great benefits in preventing age-related functional losses and in improving the perception of health-related quality of life (HRQoL) in older people. To optimize these benefits, it would be interesting to evaluate what type of exercise is better. Therefore, the purpose of this study was to assess the effects of heavy-resistance training on mobility and HRQoL in older women. Forty healthy, untrained older women (60−75 years) were randomly assigned to three groups: circuit resistance training (CRT, n = 15), traditional resistance training (TRT, n = 15) or the control group (CG, n = 10). During the 12-week training period, both experimental groups performed training with heavy loads, twice a week. Before and after the training period, the Timed Up and Go test, as a proxy of mobility, and the perception of HRQoL were evaluated. TRT and CRT resulted in a statistically significant improvement in the Timed Up and Go test (−5.4 and −10.3%, respectively; p < 0.05), but only the improvement after CRT was significantly greater than changes in the CG (p < 0.001). Only CRT elicited improvements in several dimensions of the perception of the HRQoL questionnaire, such as: physical functioning (13%, p < 0.001), general health (8.1%; p = 0.048), vitality (17.7%; p < 0.001), role emotional (6.7%; p = 0.044) and physical component summary (6.3%; p = 0.001). The change in the CRT group was greater than in the CG (p < 0.001) in the physical functioning score. The present findings show that CRT might be a time- (and hence cost-) effective alternative to trigger multiple positive functional and psychological adaptations in older women.

Acute effects of transcranial direct current stimulation on cycling and running performance. A systematic review and meta-analysis.

Transcranial direct current stimulation (tDCS) has been proven to induce positive effects on athletic performance. The present study aimed to analyse the effect of anodal-tDCS on endurance (time to exhaustion [TTE] or endurance time trial [ETT]) and sprint performance during cycling and running tasks. We performed a systematic literature review in the databases Medline (via PubMed), SPORTDiscus and Science Direct. We included only randomised controlled trials conducted with healthy individuals in which an anodal-tDCS protocol was applied prior to cycling or running tests. The effect of anodal-tDCS (experimental condition) was compared against sham stimulation (control condition). A total of 15 interventions from 13 studies were included. The sub-group analysis revealed a positive effect of anodal-tDCS on TTE (standardised mean differences [SMD] = 0.37; 90% confidence interval [CI] = 0.13, 0.61; p = 0.01), but not on ETT (SMD = 0.00; 90% CI = -0.29, 0.30; p = 1.00) or sprint performance (SMD = 0.19; 90% CI = -0.23, 0.60; p = 0.46). The current meta-analysis suggests that the effect of anodal-tDCS on whole-body dynamic exercises (running and cycling) could be task dependent. Specifically, anodal-tDCS enhance running and cycling time to exhaustion performance during TTE tasks but not ETT or sprint tasks. The increase in cortical excitability induced by anodal-tDCS may lead to lower ratings of perceived exertion by reducing the input required to perform the physical task. Task should be taken into account, because it is probably influencing the result obtained by anodal-tDCS.

Acute psychophysiological responses during exercise while using resistive respiratory devices: A systematic review.

Different studies have observed that respiratory muscle training (RMT) improve the endurance and strength of the respiratory muscles, having a positive impact on performance of endurance sports. Nevertheless, it remains to be clarified how to improve the efficiency of such training. The objective of this systematic review was to evaluate the acute physiological responses produced by training the respiratory muscles during exercise with flow resistive devices because such information may support us improve the efficiency of this type of training. A search in the Medline, Science Direct, Web of Science and Scopus databases was conducted, following the PRISMA guidelines. The methodological quality of the articles was assessed using the PEDro scale. Nineteen studies met the inclusion criteria and a total of 212 subjects were included in the studies. The RMT method used in all studies was flow resistive loading, whereas the constant load exercise was the most common type of exercise among the studies. The results obtained seem to indicate that the use of this type of training during exercise reduces the performance, the lactate (La-) values and the ventilation, whereas the end - tidal partial pressure of carbon dioxide (PCO2) is increased.

Transcranial direct current stimulation and repeated sprint ability: No effect on sprint performance or ratings of perceived exertion.

The role of transcranial direct current stimulation (tDCS) as an ergogenic aid is receiving attention from scientists to optimize sport performance. Most studies have examined the effects of tDCS on endurance performance during continuous tasks, while the effect of tDCS on high-intensity intermittent tasks has been less investigated. Therefore, this study aimed to explore the acute effects of tDCS on sprint performance and ratings of perceived exertion (RPE) during a repeated sprint ability (RSA) task. Twenty-five healthy males (age: 22.0 ± 2.5 years) participated in a randomized crossover study consisting of three experimental sessions (anodal, cathodal or sham tDCS) separated by 1 week. Each session consisted of (I) tDCS protocol (15 min at 2 mA applied over the dorsolateral prefrontal cortex [DLPFC]), (II) warm-up and (III) RSA task (ten 30-m running sprints separated by 30 s). Total time and RPE values were recorded for each sprint. The two-way ANOVA applied on sprint time did not reveal a significant main effect of tDCS condition (p = .200) neither a significant tDCS condition × number of sprint interaction (p = .716). Similarly, no significant differences were observed for the fatigue index (p = .449), RSAmean (p = .200) or RPE after each sprint (p range = .116-.890). The magnitude of the differences between the tDCS conditions ranged from negligible to small (effect sizes ≤ 0.33). These results suggest that the application of tDCS over the DLPFC is not effective to increase sprint performance or reduce RPE during a RSA task.HIGHLIGHTSTranscranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique that could modulate neuromuscular performance.This study aimed to explore the short-term effects of tDCS on sprint performance and ratings of perceived exertion (RPE) during a repeated sprint ability (RSA) task.The application of either ANODAL or CATHODAL tDCS over the DLPFC for 15 minutes did not affect the sprint time of single repeated sprints or the overall metrics of RSA performance (RSAmean and fatigue index).The application of either ANODAL or CATHODAL tDCS over the DLPFC for 15 minutes did not affect the ratings of perceived exertion measured during the repeated sprints task.

Transcranial Direct Current Stimulation Does Not Affect Sprint Performance or the Horizontal Force-Velocity Profile.

Purpose: The aim of this study was to explore the effects of transcranial direct current stimulation (tDCS) on sprint performance and the horizontal force-velocity (F-v) profile. Method: Thirty-two healthy subjects (25 men and 7 women; age = 21.8 ± 2.4 years) completed three sessions separated by 1 week following a double-blinded crossover design. Each session consisted of two maximal sprints of 30 meters that were performed after applying ANODAL, CATHODAL or SHAM tDCS over the left dorsolateral prefrontal cortex (DLPFC) for 15 minutes at 2 mA. The 30-m time and the horizontal F-v profile variables (theoretical maximal force [F0], theoretical maximal velocity, Fv slope, maximal power [Pmax], decrease in the ratio of horizontal-to-resultant force, and maximal ratio of horizontal-to-resultant force) were compared between the tDCS conditions. Results: No significant differences between the tDCS conditions were observed for any variable (p range = 0.061 to 0.842). The magnitude of the differences was negligible for most of the comparisons (effect size [ES] < 0.20) with the only exception of Pmax and F0 which were greater for the ANODAL compared to the SHAM condition (both ES = 0.20). Conclusions: The application of tDCS over the DLPFC is not effective to increase non-fatigued sprint performance.

Power-load curve in trained sprinters.

The levels of lower-limb strength and power can distinguish between athletes of different levels in a number of sports, specifically in sprinting. In this sense, the purposes of this study were (a) to define the power­load curve in a modified half squat machine in trained sprinters in the competitive cycle and (b) to correlate the peak power (PP) production with 60-m sprint performance. In this sense, a cross-sectional study was carried out with 10 national level sprinters. After the calculation of 1 repetition maximum (1RM) of the participants, a progressive test, which consisted of moving loads of 30, 45, 60, 70, and 80% of the 1RM as quickly as possible in the concentric phase, was performed. It was found that PP occurred at 60% of 1RM. The power output with all loads was not significantly different (p ≤ 0.05) from each other. No significant correlations were found between 60-m performance and PP with the different loads. Therefore, we may conclude that the sprinters of national level analyzed present values of PP output, in the competitive period, near to 60% of 1RM in the half squat exercise; however, this power is not significantly different from the other loads.

Effect of a semi-immersive virtual reality navigation therapy on quality of life in persons with spinal cord injury.

PURPOSE: This study aims to develop a sailing simulation-based therapeutic rehabilitation program for individuals with Spinal Cord Injuries (SCI) during the subacute phase of the injury. METHODS: Participants were 11 patients, aged between 20-56 years (Mage = 42.36, SDage=12.90), who were randomly assigned into experimental group and control group, within a pre-test/post-test quasi-experimental design. While both groups followed the rehabilitation programmed by the hospital, experimental group participants were enrolled in an interactive rehabilitation exercise (The vSail-Access®, Virtual Sailing Pty Ltd). For this intervention, each subject underwent a semi-immersive Virtual Reality (VR) navigation therapy for 30-40 min per day, three times per week for six weeks. Quality of life (QoL), functionality and balance variables were measured for both groups one week before and after the intervention. Data was generated based on patients' responses using validated questionnaires and tests. A 2 (groups) × 2 (test-time) MANOVA was performed to detect between-group and within-group differences. RESULTS: Significant improvements were obtained in the experimental group in the mobility and balance variables, and in the global result of QoL. CONCLUSIONS: The sailing simulation program, included as a therapy within the rehabilitation process after a SCI, provides participants with an overall increase in QoL and functionality.IMPLICATIONS FOR REHABILIATIONVirtual reality is a therapy that can be part of the rehabilitation process of spinal cord injuries in the acute phase, improving functional capacity.The initiation to recreational sailing in a virtual way is a safe tool for the initiation to the practice of sports.The practice of a dynamic sport, such as sailing, helps to improve the quality of life in spinal cord injuries.