Self-Selected Motivational Music Enhances Physical Performance in Normoxia and Hypoxia in Young Healthy Males

Humans exposed to hypoxia are susceptible to physiological and psychological impairment. Music has ergogenic effects through enhancing psychological factors such as mood, emotion, and cognition. This study aimed to investigate music as a tool for mitigating the performance decrements observed in hypoxia. Thirteen males (mean ± SD; 24 ± 4 years) completed one familiarization session and four experimental trials; (1) normoxia (sea level, 0.209 FiO2) and no music; (2) normoxia (0.209 FiO2) with music; (3) normobaric hypoxia (∼3800 m, 0.13 FiO2) and no music; and (4) normobaric hypoxia (0.13 FiO2) with music. Experimental trials were completed at 21°C with 50% relative humidity. Music was self-selected prior to the familiarization session. Each experimental trial included a 15-min time trial on an arm bike, followed by a 60-s isometric maximal voluntary contraction (MVC) of the biceps brachii. Supramaximal nerve stimulation quantified central and peripheral fatigue with voluntary activation (VA%) calculated using the doublet interpolation method. Average power output (W) was reduced with a main effect of hypoxia (p = 0.02) and significantly increased with a main effect of music (p = 0.001). When combined the interaction was additive (p = 0.87). Average MVC force (N) was reduced in hypoxia (p = 0.03) but VA% of the biceps brachii was increased with music (p = 0.02). Music reduced subjective scores of mental effort, breathing discomfort, and arm discomfort in hypoxia (p < 0.001). Music increased maximal physical exertion through enhancing neural drive and diminishing detrimental mental processes, enhancing performance in normoxia (6.3%) and hypoxia (6.4%).

Estimating Resting HRV during fMRI: A Comparison between Laboratory and Scanner Environment

Heart rate variability (HRV) is regularly assessed in neuroimaging studies as an indicator of autonomic, emotional or cognitive processes. In this study, we investigated the influence of a loud and cramped environment during magnetic resonance imaging (MRI) on resting HRV measures. We compared recordings during functional MRI sessions with recordings in our autonomic laboratory (LAB) in 101 healthy subjects. In the LAB, we recorded an electrocardiogram (ECG) and a photoplethysmogram (PPG) over 15 min. During resting state functional MRI, we acquired a PPG for 15 min. We assessed anxiety levels before the scanning in each subject. In 27 participants, we performed follow-up sessions to investigate a possible effect of habituation. We found a high intra-class correlation ranging between 0.775 and 0.996, indicating high consistency across conditions. We observed no systematic influence of the MRI environment on any HRV index when PPG signals were analyzed. However, SDNN and RMSSD were significantly higher when extracted from the PPG compared to the ECG. Although we found a significant correlation of anxiety and the decrease in HRV from LAB to MRI, a familiarization session did not change the HRV outcome. Our results suggest that psychological factors are less influential on the HRV outcome during MRI than the methodological choice of the cardiac signal to analyze.

Cardiovascular and nitric oxide response after maximal voluntary isometric contraction in adolescents with and without Down Syndrome v1

Background This study was designed to compare the cardiovascular and nitric oxide (NO) responses to maximal voluntary isometric contraction (MVIC) with different muscle groups (leg press [LEP] and isometric handgrip [IHG] exercise) of adolescents with Down syndrome (DS) and age-matched non-DS peers. We also aimed to compare the absolute and relative IHG strength between groups. MethodsEleven adolescents with DS (14.1 ± 1.0 years) and ten without DS (13.7 ± 1.25 years)participants performed two experimental sessions of LEP and IHG exercises: 1) familiarization session and 2) 3 attempts x 5-sec contraction at MVIC with 3-min rest interval. Blood pressure (BP), heart rate (HR) and NO were collected at rest, immediately post-exercise session, and 10-min post-exercise. Results There were no differences for cardiovascular and NO responses between groups for MVIC test using different muscle groups. However, DS group displayed a lower but not significantly cardiovascular response at rest and after MVIC tests than controls. Furthermore, DS group displayed a higher NO- concentration at rest, recovery and after IHG when compared to controls (P< 0.05). In addition, DS adolescents displayed a significantly lower level in absolute and relative IHG strength when compared to controls (P = 0.001). Conclusions Individuals with DS display a lower cardiovascular response at rest and after MVIC tests than controls and higher NO response after exercise.

Do Age and Sex Play a Role in the Intraocular Pressure Changes after Acrobatic Gymnastics?

To evaluate the effects of an acrobatic gymnastics (AG) training session on intraocular pressure (IOP), a familiarization session was employed to confirm the participant’s suitability for the study. Forty-nine gymnasts (63.27% females, 18–40 years old) voluntarily agreed to participate. As age, sex, baseline IOP, and central corneal thickness (CCT) were considered as potential predictors of the IOP variations, in the second session measurements of the above parameters were taken before and after 90 min of AG. A mixed-factorial analysis of variance evaluated differences. Linear regression was conducted to potentially predict the IOP variation with the exercise. After the scheduled exercise, highly significant (p < 0.001, effect size: 0.73) reductions in IOP, but no significant changes in CCT (p = 0.229), were observed. IOP was significantly modified in males, older than 25 years, and subjects with baseline IOP > 14 mmHg (p ≤ 0.001, effect sizes: 0.57–1.02). In contrast, the IOP of females, younger participants, and subjects with baseline IOP ≤ 14 mmHg was not significantly modified (p = 0.114). With the regression analyses, we concluded that both sex and baseline IOP levels were significant predictors of the IOP fluctuation with AG. These findings could be of interest for gymnasts, coaches, ophthalmologists, and/or optometrists in the prevention and control of risk factors associated with glaucoma.

Resisted Sled Sprint Kinematics: The Acute Effect of Load and Sporting Population

In this study, we assessed the acute kinematic effects of different sled load conditions (unloaded and at 10%, 20%, 30% decrement from maximum velocity (Vdec)) in different sporting populations. It is well-known that an athlete’s kinematics change with increasing sled load. However, to our knowledge, the relationship between the different loads in resisted sled sprinting (RSS) and kinematic characteristics is unknown. Thirty-three athletes (sprinters n = 10; team sport athletes n = 23) performed a familiarization session (day 1), and 12 sprints at different loads (day 2) over a distance of 40 m. Sprint time and average velocity were measured. Sagittal-plane high-speed video data was recorded for early acceleration and maximum velocity phase and joint angles computed. Loading introduced significant changes to hip, knee, ankle, and trunk angle for touch-down and toe-off for the acceleration and maximum velocity phase (p < 0.05). Knee, hip, and ankle angles became more flexed with increasing load for all groups and trunk lean increased linearly with increasing loading conditions. The results of this study provide coaches with important information that may influence how RSS is employed as a training tool to improve sprint performance for acceleration and maximal velocity running and that prescription may not change based on sporting population, as there were only minimal differences observed between groups. The trunk lean increase was related to the heavy loads and appeared to prevent athletes to reach mechanics that were truly reflective of maximum velocity sprinting. Lighter loads seem to be more adequate to not provoke changes in maxV kinematics. However, heavy loading extended the distance over which it is possible to train acceleration.

Total Training Volume and Muscle Soreness Parameters Performing Agonist or Antagonist Foam Rolling between Sets

Background: Foam rolling (FR) has become very popular in recent years; however, the practice of FR between sets of resistance training (RT) for the lower limbs needs further examination. Purpose: Therefore, the purpose of the present study was to examine the effect of FR for the agonists (quadriceps) and antagonists (hamstrings) between multiple sets of the leg extension on repetition maximum performance (RM), fatigue resistance index (FRI), and muscle soreness (MS). Study design: Quasi-experimental clinical trial. Methods: Twenty trained men participated in this study (30.35 ± 6.56 years, 1.77 ± 0.05 cm, 87.70 ± 7.6 kg) and attended seven sessions with 48 h between sessions, (one familiarization session; two 10-RM test and retest sessions; and four experimental sessions). The four experimental sessions were performed in random order and included: agonist foam rolling (AFR), antagonist foam rolling (ANTFR), agonist/antagonist foam rolling (A/ANTFR), and traditional control (TP, without foam rolling). All sessions consisted of three sets for maximal repetitions with a 10-RM load for the leg extension. In the AFR and ANTFR sessions, there was a 120 s rest interval between sets, during which FR was done for the agonists or antagonists, respectively. In the A/ANTFR protocol, there was a 120 s rest interval between sets, during which FR was done for the agonists and antagonists. In the traditional protocol (TP), there was a 120 s passive rest interval between sets. Results: Regarding the total training volume (TTV), significant differences were noted between sessions (F3,57 = 11.014; p = 0.0001). The AFR, ANTFR, and A/ANTFR sessions had significantly higher TTV versus the TP (p < 0.05). Regarding the FRI, significant differences were noted between sessions (F3,57 = 2917, p = 0.042). A significantly higher fatigue index was shown for the ANTFR and AFR sessions versus the TP (p < 0.05). Regarding the total number of repetitions, significant differences were noted between sessions (F3,57 = 11.086, p = 0.0001). The total number of repetitions was significantly higher in the A/ANTFR, ANTFR, and AFR versus the TP session (p < 0.05). MS was significantly lower in the A/ANTFR, ANTFR, and AFR sessions versus the TP session (p < 0.05). Conclusion: In conclusion, foam rolling between sets for the agonist or antagonist separately or in succession, resulted in greater neuromuscular performance and higher fatigue indices, as well as reducing the perception of acute muscle soreness.

The Torque Referenced to a Perceived Exertion Level Is Affected by the Type of Movement in Men With Spinal Cord Injury

Objectives: To compare a standardized submaximal intensity (based on the rate of perceived exertion [RPE]) with the percentage of the average and peak torque during a familiarization session in individuals with different spinal cord injury (SCI) levels in gravity-resisted and gravity-assisted movements. Methods: This was a cross-sectional study at a rehabilitation hospital. Thirty-six individuals stratified in tetraplegia (TP), high paraplegia (HP), and low paraplegia (LP) groups and 12 matched control participants (CG) were enrolled in the study. Participants performed a maximum strength test using isokinetic dynamometry. The familiarization consisted of 10 submaximal repetitions with a level 2 (i.e., 20% of the maximum score) in the Resistance Exercise Scale (OMNI-RES). Fisher’s exact test compared the percentages of the average torque (%ATFam) and peak torque (%PTFam) of the familiarization (based on the peak torque during the maximum strength tests) to the %ATFam and %PTFam attained with 20% of RPE. The coefficient of variation (CV) was calculated to assess the torque dispersion during each familiarization set. Results: The %ATFam was lower for gravity-assisted compared to gravity-resisted movements for HP, LP, and CG (p ≤ .05). The CV was significantly lower in gravity-resisted movements during familiarization for TP, LP, and CG. Conclusion: Different RPE levels should be adopted for gravity-resisted or gravity-assisted upper limb exercises to maintain the same relative intensity during a familiarization session.

Análisis cinético y cinemático de un press de banca a diferentes intensidades de carga (Kinetic y kinematic analysis of a bench press at different load intensities)

El press de banca (PB) es uno de ejercicios con más tradición en las ciencias del deporte. Su estudio ha sido abordado desde diferentes perspectivas, principalmente analizando los efectos de variantes técnicas orientadas a mejorar la programación del entrenamiento en diferentes deportes y poblaciones. La repetición máxima ha sido utilizada como referencia para cuantificar la carga en diversidad de estudios. Sin embargo, es necesario conocer cómo ajustar las intensidades de entrenamiento para poder programar con mayor precisión. El objetivo de la presente investigación fue analizar el comportamiento de las variables cinéticas, cinemáticas y psicológicas a distintos porcentajes de la 1RM (repetición máxima) del PB. Treinta estudiantes universitarios sanos formaron parte de la muestra experimental (Edad 23 ± 0,45 años; talla 181,13 ± 2,25 cm; peso 78,25 ± 4,81 Kg; porcentaje muscular 52,10 ± 0,30%, porcentaje graso 12,05 ± 0,59%; IMC 24, 12 ± 0,84). Los participantes realizaron una sesión de familiarización con la técnica del PB y realizaron un test incremental para la obtención de la 1RM. Después de 7 días volvieron a realizar el mismo protocolo, pero a diferentes intensidades de la 1RM (20%, 40%, 60%, 80% y 100%). Los datos obtenidos aportaron información descriptiva del comportamiento de las variables analizadas al aumentar la carga en sujetos entrenados. La presente investigación podría sugerir variaciones en las cargas de trabajo previstas y predecir posibles adaptaciones dentro de la programación del trabajo de fuerza. Abstract. Bench press exercise is one of the most popular exercises in sports science. It has been studied from different approaches, mostly analyzing the effects of technical variations in order to improve training schedule on different sports and populations. The one repetition maximum has been used as a reference to quantify the load in diverse studies. However, knowing how to adjust training intensities is necessary in order to schedule training accurately. The objective of the present study was to analyze the response of kinematic, kinetic and psychological variables at different percentages of 1RM. The study sample was comprised of thirty healthy university students (Age 23 ± 0.45 years; height 181.13 ± 2.25 cm; weight 78.25 ± 4.81 Kg; muscle percentage 52.10 ± 0.30%, fat percentage 12.05 ± 0.59%; BMI 24, 12 ± 0.84). The participants attended a familiarization session with the bench press technique and performed an incremental test to obtain the 1RM. They returned to carry out the same protocol seven days after, but different intensities of the 1RM were accomplished (20%, 40%, 60%, 80% and 100%). The results obtained provided descriptive data about the behaviour of the analyzed variables by increasing the load on trained subjects. The present research could suggest variations in the expected workloads and predict possible adaptations within the force work schedule.

Comparative Responses to Squats Completed with Free Weights and an Exoskeleton

To assess the comparative similarity of squat data collected as they wore a robotic exoskeleton, female athletes (n=14) did two exercise bouts spaced 14 days apart. Data from their exoskeleton workout was compared to a session they did with free weights. Each squat workout entailed a four-set, four-repetition paradigm with 60-second rest periods. Sets for each workout involved progressively heavier (22.5, 34, 45.5, 57 kg) loads. The same physiological, perceptual, and exercise performance dependent variables were measured and collected from both workouts. Per dependent variable, Pearson correlation coefficients, t-tests, and Cohen's d effect size compared the degree of similarity between values obtained from the exoskeleton and free weight workouts. Results show peak O2, heart rate, and peak force data produced the least variability. In contrast, far more inter-workout variability was noted for peak velocity, peak power, and electromyography (EMG) values. Overall, an insufficient amount of comparative similarity exists for data collected from both workouts. Due to the limited data similarity, the exoskeleton does not exhibit an acceptable degree of validity. Likely the cause for the limited similarity was due to the brief amount of familiarization subjects had to the exoskeleton prior to actual data collection. A familiarization session that accustomed subjects to squats done with the exoskeleton prior to actual data collection may have considerably improved the validity of data obtained from that device.

Familiarization and Reliability of the Isometric Knee Extension Test for Rapid Force Production Assessment

Despite the rising interest in the use of portable force sensors during isometric exercises to inform on neuromuscular performance, the design of practical field-based methods to obtain reliable measures is an ongoing challenge. We aim at identifying the intra-session and test-retest reliability of a rapid, isometric knee extension test to evaluate the maximal voluntary concentric force (MVC), rate of force development (RFD) and impulse following a field-based approach. On two occasions, 14 athletes unfamiliar with the test completed three sets of 2 s ballistic contractions (as fast and hard as possible) with 30 s rest. Raw and filtered data were collected in real time using a portable force sensor. RFD and impulse were highly reliability during “late” phases of the contraction (0–250 ms) since the first session (coefficient of variation (CV) < 9.8%). Earlier phases (0–150 ms) achieved a moderate reliability after one familiarization session (CV < 7.1%). Measures at 0–50 ms did not reach sufficient reliability (CV~14%). MVC was accurately assessed. Dominant limbs were not importantly altered by the familiarization. In opposite, non-dominant limbs showed large variations. New evidence is provided about the positive effects of a single familiarization session to improve the reliability the isometric knee extension test for rapid force production assessment. Coaches and practitioners may benefit of from these findings to conduct practical and reliable assessments of the rapid force production using a portable force sensor and a field-based approach.