Reliability and Validity of the Strain Gauge "GSTRENGTH" for Measuring Peak Force in the Isometric Belt Squat at Different Joint Angles.

Since isometric training is gaining popularity, some devices are being developed to test isometric force as an alternative to the more expensive force plates (FPs); thus, the aim of this study was to test the reliability and validity of "GSTRENGTH" for measuring PF in the isometric belt squat exercise. Five subjects performed 24 contractions at three different knee angles (90°, 105° and 120°) on two occasions (120 total cases). Peak force data were measured using FPs and a strain gauge (SG) and analyzed by Pearson's product-moment correlation coefficient, ICCs, Cronbach's alpha, a paired sample t-test and Bland-Altman plots. Perfect or almost perfect relationships (r: 0.999-1) were found with an almost perfect or perfect level of agreement (ICCs: 0.992-1; α: 0.998-1). The t-test showed significant differences for the raw data but not for the predictions by the equations obtained with the SG values. The Bland-Altman plots, when significant, showed trivial to moderate values for systematic bias in general. In conclusion, "GSTRENGTH" was shown to be a valid alternative to FPs for measuring PF.

Comparative Effects of Sodium Bicarbonate and Intravenous Lipid Emulsions on Reversing Bupivacaine-Induced Electrophysiological Toxicity in a Porcine Experimental Model.

BACKGROUND: Bupivacaine cardiotoxicity mainly manifests as inhibition of the cardiac sodium channel, which slows conduction, particularly at the ventricular level. Experimental studies have demonstrated that intravenous lipid emulsions (ILEs) can reduce the cardiotoxic effects of bupivacaine, but the extent of these effects is controversial. Sodium bicarbonate (B) represents the standard treatment of toxicity related to sodium channel-blocking drugs. The aim of this study was to compare the effects of ILEs and B on the speed of recovery from bupivacaine-induced effects on the electrocardiographic parameters. METHODS: Bupivacaine 4 mg/kg was administered to 24 anesthetized pigs. Three minutes after delivering the bupivacaine bolus, the animals were given the following: ILE 1.5 mL/kg followed by 0.25 mL/kg/min (ILE group) and B 2 mEq/kg followed by 1 mEq/kg/h (B group). Controls (C group) were given saline solution, 50 mL followed by 1 mL/kg/h. Electrophysiological parameters were evaluated in sinus rhythm and during right ventricular pacing at several time intervals up to 30 minutes. Data were analyzed as the area under the curve (AUC) for the first 10 minutes (AUC10) or 30 minutes (AUC30). RESULTS: Bupivacaine increased the sinus cycle length, PR interval, and QRS duration. AUC30 of the sinus rhythm QRS duration after antidote administration was significantly different among the 3 groups (P = .003). B group experienced faster recovery from intoxication than the C group (AUC10, P = .003; AUC30, P = .003) or the ILE group (AUC10, P = .018). During the first minute, 50% of the B group (versus 0% of the ILE and C groups) had recovered >30% of QRS duration (P = .011). The trend toward faster recovery in the ILE group than in the C group did not reach significance (AUC10, P = .23; AUC30, P = .06). Effects on the paced QRS duration at a rate of 150 bpm were more intense but with similar results (B versus C group: AUC10, P = .009; AUC30, P = .009; B versus ILE: AUC10, P = .015; AUC30, P = .024). The recovery process of the paced QRS tended to be slower for all antidotes. CONCLUSIONS: In a closed-chest swine model, B was an effective treatment for electrophysiological alterations caused by established bupivacaine toxicity. At clinical doses, B ameliorated bupivacaine electrocardiographic toxicity faster than ILE. Use-dependent effects of bupivacaine are prominent and delay the effects of both antidotes, but B produces faster recovery than ILE.

Greater Neuromuscular and Perceptual Fatigue after Low versus High Loads in the Bench Press: A Preliminary Study Applying Frequentist and Bayesian Group Analyses with Subject-by-Subject Case Series Reports.

Background/Objective: This study investigated the differences in acute fatigue following resistance training performed with low versus high loads in the bench press (BP). Methods: Trained males (n = 5, 21.2 ± 2.77 years; 81.86 ± 6.67 kg; 177 ± 7.52 cm) undertook three protocols with 50%RM and three with 85%RM with volume equalized between protocols: muscular failure protocols (TF, RTP1 and 2), half-maximum repetition protocols (RTP3 and 4), and cluster set protocols (RTP5 and 6). Mechanical performance, lactate, and perceptual responses were analyzed during protocols and at post 0, 24, and 48 h using frequentist (p < 0.05) and Bayesian approaches. Results: Moderate to large (ES ≥ 0.3) and trivial to moderate (ES < 0.3) effects were observed at 0 and 24 h post-session, respectively, across all protocols. TF protocols, particularly RTP1, showed the greatest impairments when compared to the other RTP (ES ≥ 0.3). The Bayesian analysis supported the frequentist results, showing strong-decisive evidence for our data under the model that included protocols as predictors for mechanical, metabolic, and perceptual variables during protocols. Inter-individual variability in responses was observed in the neuromuscular tests, potentially related to the strength level and perceptual responses. Conclusions: In summary, TF generates greater fatigue, while reducing set volume to half of maximum repetitions or including intra-set rest that helps to mitigate fatigue symptoms.

Assessment of cardiotoxicity and plasma ropivacaine concentrations after serratus intercostal fascial plane block in an experimental model.

Serratus intercostal fascial plane block (SIFPB) has emerged as an alternative to paravertebral block in breast surgery. It involves the administration of high volumes and doses of local anesthetics (LA) that can potentially reach toxic levels. Ropivacaine is widely used in thoraco-fascial blocks; however, there is no information on the plasma concentrations attained after SIPFB and whether they are associated with cardiotoxicity. Plasma concentrations of ropivacaine and its electrophysiological effects were evaluated in eight pigs after bilateral SIFPB with ropivacaine in doses of 3 mg/kg. Plasma concentrations, electrophysiological and hemodynamic parameters were measured sequentially for the following 180 min until the end of the study. The area under the curve, the maximum plasma concentration (Cmax) and the time to reach Cmax (tmax) were calculated. The median arterial ropivacaine concentration Cmax was, 2.34 [1.40 to 3.74] µg/ml. The time to reach the highest concentration was 15 [10 to 20] min. Twenty-five percent of the animals had arterial concentrations above the lower limit concentration of ropivacaine for LA systemic toxicity (3.4 µg/ml). No alterations were observed in the electrophysiological or electrocardiographic parameters except for a prolongation of the QTc interval, from 489 ± 30 to 544 ± 44 ms (Δ11.38 ± 6%), P = 0.01. Hemodynamic parameters remained in the physiological range throughout the study. SIFPB with ropivacaine in doses of 3 mg/kg has reached potentially toxic levels, however, it has not been associated with adverse electrophysiological or hemodynamic effects.

Sodium bicarbonate reverts electrophysiologic cardiotoxicity of ropivacaine faster than lipid emulsions in a porcine model.

Ropivacaine has been described as a safer local anaesthetic (LA); however, serious cardiotoxic accidents have been reported. Intravenous-lipid-emulsion (ILE) therapy during LA intoxication seems to act as an antidote. Sodium bicarbonate is the standard treatment for sodium channel blocker drug toxicity. We compared both antidotes on the reversion of electrophysiologic toxicity induced by ropivacaine. Ropivacaine 5 mg kg-1 was administered in 24 pigs, and 3 min later, the animals received ILE: 1.5 ml kg-1  + 0.25 ml kg-1  min-1 (ILE group); sodium bicarbonate: 2 mEq kg-1  + 1 mEq kg-1  h-1 (NaHCO3 group); saline solution (CTL group). Electrophysiological parameters were evaluated for 30 min. The area under the curve (AUC) for the first 5 or 30 min was compared between groups. Ropivacaine induced a lengthening of the PR interval by 17% (P = 0.0001), His-ventricle-interval by 58% (P = 0.001), sinus QRS complex by 56% (P = 0.0001), paced QRS at 150 bpm by 257% (P = 0.0001), and at 120 bpm by 143% (P = 0.0001) in all groups. At 5 min after treatment, sinus QRS in the NaHCO3 group was shorter than that in the CTL group (AUCQRS5 , P = 0.003) or ILE group (AUCQRS5 , P = 0.045). During the first minute, seven of the animals in the NaHCO3 group vs. two in the ILE or 0 in the CTL group recovered more than 30% of the sinus QRS previously lengthened by ropivacaine (P = 0.003). Sodium bicarbonate reversed the electrophysiological toxicity of ropivacaine faster than ILE and control groups.

Effects of intravenous lipid emulsions on the reversal of pacing-induced ventricular arrhythmias and electrophysiological alterations in an animal model of ropivacaine toxicity.

INTRODUCTION: Ropivacaine is considered to have a wider margin of cardiovascular safety. However, several reports of ventricular arrhythmias (VA) due to ropivacaine toxicity have been documented. Intravenous lipid emulsions (ILEs) have recently been used successfully in the treatment of local anesthetic intoxication. The main objective of the present study was to evaluate the efficacy of the ILEs in the prevention of pacing-induced-VA and electrophysiological alterations in an animal model of ropivacaine toxicity. METHODS: Nineteen pigs were anesthetized and instrumentalized. A baseline programmed electrical ventricular stimulation protocol (PEVSP) to induce VA was performed. Ropivacaine (5 mg·kg-1 + 100 µg·kg-1·min-1) followed by normal saline infusion (control group n = 8) or intralipid 20% (1.5 mL·kg-1 + 0.25 mL·kg-1·min-1) for the ILE group (n = 8), were administered three minutes after the ropivacaine bolus. PEVSP was repeated 25 min after the onset of ropivacaine infusion. Pacing-induced VA and electrophysiological abnormalities were assessed in both groups. A sham-control group (n = 3) without ropivacaine infusion was included. RESULTS: Most of the electrophysiological parameters evaluated were affected by ropivacaine: PR interval by 28% (p = 0.001), AV interval by 40% (p = 0.001), sinus QRS by 101% (p = 0.001), paced QRS at a rate of 150 bpm by 258% (p = 0.001), and at 120 bpm by 241% (p = 0.001). Seven animals (87.5%) in the control group and eight animals (100%) in the ILE group developed sustained-VA (p = 0.30). Successful resuscitation occurred in 100% of animals in the ILE group vs. 57% of animals in the control group, p = 0.038. Pacing-induced-VA terminated at the first defibrillation attempt in 75% of the animals in the ILE group vs. 0% in the control group, p = 0.01. CONCLUSION: Ropivacaine strongly altered the parameters of ventricular conduction, thus facilitating the induction of VA. ILEs did not prevent pacing-induced VA. However, facilitated resuscitation and termination of VA were delivered at the first defibrillation attempt compared to the control group.

Rating of perceived exertion and velocity loss as variables for controlling the level of effort in the bench press exercise.

There is a growing interest in the analysis of different methods for monitor fatigue during resistance training sessions. This study aimed to (1) analyse the relationships between the percentage of performed repetitions with respect to the maximum possible number (%REP), RPE and magnitude of velocity loss (VL), and (2) examine whether a multiple regression analysis with the RPE and VL as predictor variables could improve the goodness of fit to predict %REP in the bench press exercise performed in a Smith machine. Seven men performed a repetition maximum test, on 3 separate testing sessions, against 3 different absolute loads based on a target mean velocity (MV) according to an individual load-velocity profile (≈1.00, ≈0.70, and ≈0.50 m/s). MV, VL, %REP and RPE were collected and used for analysis. Based upon quadratic polynomial regression analysis strong relationships were reported between the RPE and %REP (r2 = 0.89 and SEE = 9.85%) and between the VL and %REP (r2 = 0.91 and SEE = 9.85%). Multiple regression analysis with the RPE and VL as predictor variables improved the goodness of fit (r2 = 0.94 and SEE = 7.18%) of the model to predict %REP. These results suggest that both RPE and VL are useful variables to accurately estimate %REP in the bench press exercise.

A Cluster Set Protocol in the Half Squat Exercise Reduces Mechanical Fatigue and Lactate Concentrations in Comparison with A Traditional Set Configuration.

Splitting sets into clusters has been shown to maintain performance during resistance training. This study compared the acute fatigue produced by a traditional (TSC) versus a cluster (CSC) set configuration in the smith machine half squat exercise. Fifteen males performed a single bout of TSC and CSC separated by 72-96 h. In the TSC, participants performed as many repetitions as possible until reaching a 20% drop in barbell velocity (MPV), while in the CSC, they performed the same number of repetitions with 15 seconds inter-repetition rest. Effects of both protocols in MPV, countermovement jump height (CMJ), and blood lactate (BLa) were measured. Significant differences between protocols were found for MPV of the last repetition (0.4 vs 0.5 m/s TSC and CSC) and BLa (6.8 mmol/L vs 3.2 mmol/L TSC and CSC). Significant drop of velocity from the first to the last repetition of the set (19.9%), decrease in CMJ height (35.4 vs 32.6 cm), and increase in BLa (2.1 vs 6.8 mmol/L) pre-post-exercise was observed just for the TSC protocol. The results of the present study showed that CSC reduces the lactate response and mechanical fatigue produced by a single set on the half squat exercise in comparison with TSC.

Repetitions in reserve vs. maximum effort resistance training programs in youth female athletes.

BACKGROUND: This study aimed to analyze and compare the effects of two different resistance training programs. METHODS: Fourteen under-17 youth female basketball players were randomly assigned to repetitions in reserve (RIR, N.=7) or maximum effort (RM, N.=7) resistance training programs. The programs consisted of 3-4 sets of 4 exercises x 7-10 repetitions with 2 min of passive recovery between sets and exercises, twice a week for a period of 8 weeks. The RIR group was instructed to perform the exercises with 3 repetitions remaining (rate of perceived exertion [RPE] =7). The physical assessment included jumping, agility, and sprinting tests. Moreover, the maximum strength (one maximum-repetition [1-RM]) and muscle power output at 60% 1RM were assessed for back-squat and bench-press exercises. RESULTS: The within-group analysis showed improvements in all tests for both groups (RIR=1.3-43.9%; RM=1.3-17.2%). Between-group analyses showed a significant interaction effect (group x time) on 1-RM bench-press (F=8.07, P<0.05, η2p=0.40), favoring RIR group. CONCLUSIONS: This study reports for the first time that the use of RIR-based RPE resistance training protocol promotes improvements in high-intensity actions (sprinting, jumping, and cutting), muscle power output, and maximum strength, particularly in youth athletes. Considering the advantages of non-failure training, RIR training may be a suitable in-season training strategy. However, more studies are needed to confirm whether the training-induced benefits of this novel training strategy are significantly better as compared to other approaches.

The effect of depressive symptoms on cognition in patients with fibromyalgia.

BACKGROUND: Fibromyalgia (FM) patients frequently complain of cognitive problems, but it remains unclear whether these cognitive complaints can be attributed to a dysfunction of the central nervous system or if they can be explained by other factors associated with the disease, such as depression, anxiety and sleep dysfunction. METHODS: One hundred and ten patients with FM were compared with thirty-three patients diagnosed with a depressive disorder (DD) and fifty healthy controls (HC). Several measures of attention and executive functions were used to make these comparisons and the patients were also asked to complete questionnaires on depression, anxiety and sleep quality. Univariate analyses of covariance (ANCOVA) were performed to identify and control confounders and multiple linear models were used to examine the effects of fibromyalgia and depression on cognitive measures. RESULTS: FM and HC differed significantly with respect to depression, anxiety and sleep dysfunction, whereas FM and DD did not differ in terms of symptoms of depression and anxiety. However, FM was associated with a worse quality of sleep than DD. Comparisons of cognitive performance between groups showed that short-term and working memory and inattention measures were only associated with symptoms of depression, whereas selective attention was associated with both depression and fibromyalgia, and processing speed, cognitive flexibility and inhibitory control showed a significant interaction between depression and fibromyalgia. Moreover, cognitive flexibility and inhibition abilities were specifically associated with FM. CONCLUSION: FM patients show a cluster of cognitive impairment in the attentional and executive domains, although some of the symptoms observed could be explained by the severity of the symptoms of depression, while others seem to depend on the effects of fibromyalgia. Implications of the findings for the understanding and management of cognitive impairment of FM patients are discussed.

Validity of a novel inertial measurement unit to track barbell velocity / Validación de un nuevo sensor inercial para medir la velocidad de ejecución

The objective of this work is to analyze the reliability and validity of the new inertial measurement unit (IMU) PUSHTM Band2.0 to measure barbell velocity. Six healthy males (24.83±3.71years; 69.88±8.36kg; 175.92±4.5cm) participated in this studyand performed several sets on the bench press. Barbell concentric mean (MV) and peak (PV) velocity were recorded witha LT and the IMU. Pearson correlation coefficient shows a very high relationship for MV (r = 0.97; SEE: 0.08 m/s; 95%CI: 0.95-0.98; p< 0.001) and PV (r = 0.97; SEE: 0.13 m/s; 95%CI: 0.96-0.98; p< 0.001). There was a very high agreement for the values ofMV and PV (MV: ICC = 0.945, CI = 0.834–0.974, α = 0.981; PV: ICC = 0.926, CI = 0.708–0.969, α = 0.977). Paired sample t-testrevealed systematic bias for MV (p< 0.001; mean difference between instruments = 0.06 ± 0.09 m/s) and PV (p< 0.001; meandifference between instruments = 0.15 ± 0.18 m/s). Bland-Altman plots showed almost trivial and moderate relationships forMV (r2 = 0.1) and PV (r2 = 0.37). In conclusion, the PUSHTM Band 2.0 was proven to be a valid alternative for measuring barbellvelocity in the bench press.(AU)

El objetivo de este trabajo es analizar la fiabilidad y validez de la nueva unidad de medición inercial (IMU) PUSHTM Band 2.0para medir la velocidad de la barra. Seis hombres sanos (24.83 ± 3.71 años; 69.88 ± 8.36 kg; 175.92 ± 4.5 cm) participaron eneste estudio y realizaron varias series en el press de banca. La velocidad concéntrica de barra (MV) y la velocidad pico (PV)se registraron con un LT y la IMU. El coeficiente de correlación de Pearson muestra una relación muy alta para MV (r = 0.97;SEE: 0.08 m/s; IC 95%: 0.95-0.98; p <0.001) y PV (r = 0.97; SEE: 0.13 m/s; 95% IC: 0,96-0,98; p <0,001). Hubo un acuerdo muyalto para los valores de MV y PV (MV: ICC = 0.945, CI = 0.834–0.974, α = 0.981; PV: ICC = 0.926, CI = 0.708–0.969, α = 0.977). Laprueba t de muestras relacionadas reveló un sesgo sistemático para MV (p <0.001; diferencia media entre instrumentos = 0.06± 0.09 m/s) y PV (p <0.001; diferencia media entre instrumentos = 0.15 ± 0.18 m/s). Las gráficas de Bland-Altman mostraronrelaciones casi triviales y moderadas para VM (r2 = 0.1) y VP (r2 = 0.37). En conclusión, se demostró que PUSHTM Band 2.0 esuna alternativa válida para medir la velocidad de la barra en el press de banca.(AU)

Control de la pérdida de velocidad a través dela escala de esfuerzo percibido en press de banca / Control of the velocity loss through the scale of perceived effort in bench press

Controlar las variables de entrenamiento es vital para garantizar las adaptaciones deseadas en el entrenamiento de fuerza, siendo la intensidad especialmente importante para mejorar la fuerza máxima y el RFD. La velocidad de ejecución ha resultado ser la mejor variable para monitorizar la intensidad del entrenamiento de fuerza, en particular las pérdidas de velocidad relacionadas con la fatiga. Sin embargo, existen impedimentos materiales para poder utilizar esta variable. Por tanto, el objetivo de este trabajo es analizar la relación entre el RPE y las pérdidas de velocidad como alternativa para controlar el entrenamiento. Se midió a 5 sujetos (4 hombres y 1 mujer) pertenecientes a la selección española de lucha libre olímpica un total de 15 series de press de banca (3 series/sujeto), de las cuales solo 14 se incluyeron en el análisis estadístico por incumplir una de ellas el protocolo, con 3 cargas relativas distintas (5 series/carga) y una pérdida de velocidad entre 20%-32%. Las variables dependientes fueron: RPE, la pérdida de velocidad, el número de repeticiones realizadas en cada serie y velocidad de la mejor repetición de cada serie. Se analizaron las correlaciones entre las variables RPE-pérdida de velocidad; RPE-número de repeticiones; RPE-velocidad mejor repetición, obteniéndose solamente correlación significativa (r Pearson 0,843; P < 0,001) entre el RPE y la pérdida de velocidad; la correlaciones entre el RPE-número de repeticiones y RPE-velocidad mejor repetición no mostraron significación estadística. Estos resultados podrían indicar la posibilidad de gestionar la fatiga y la intensidad del entrenamiento utilizando la relación RPE-pérdida de velocidad, aunque es necesario llevar a cabo estudios similares con tamaños muestrales mayores que refuercen los resultados obtenidos en este estudio

Controlling the training variables is vital to ensure the desired adaptations in resistance training; intensity is the most important variable to improve maximum strength and rate of force development (RFD). The movement velocity has shown to be the best variable to monitor the intensity of resistance training, in particular the velocity loss related to fatigue. However, there are material impediments to use this variable. Therefore, the aim of this paper is to analyze the relationship between RPE and velocity losses as an alternative to control training. Sample included 5 subjects (4 men and 1 woman) from the Spanish Olympic Wrestling team who performed a total of 15 sets of bench press (3 set/subject), of which only 14 were included in the statistical analysis for breaching one of them the protocol, with 3 different relative loads (5 set/load) and a velocity loss between 20%-32%. The dependent variables were: RPE, the velocity loss, the number of repetitions performed in each set and the velocity of the best repetition of each set. The correlations between the RPE-velocity loss; RPE-number of repetitions; and RPE-velocity best repetition variables were analyzed, obtaining only significant correlation (r Pearson 0.843, P < 0.001) between the RPE and the velocity loss; correlations between RPE-number of repetitions; and RPE-velocity best repetition did not show statistical significance . The results of the present work could indicate the possibility of managing fatigue and controlling training intensity using the RPE-velocity loss relationship, although it is necessary to carry out similar studies with larger sample sizes that reinforce the results of this study