A Bioimpedance Spectroscopy Interface for EIM Based on IF-Sampling and Pseudo 2-Path SC Bandpass ΔΣ ADC.

This paper presents a low-noise bioimpedance (bio-Z) spectroscopy interface for electrical impedance myography (EIM) over the 1 kHz to 2 MHz frequency range. The proposed interface employs a sinusoidal signal generator based on direct-digital-synthesis (DDS) to improve the accuracy of the bio-Z reading, and a quadrature low-intermediate frequency (IF) readout to achieve a good noise-to-power efficiency and the required data throughput to detect muscle contractions. The readout is able to measure baseline and time-varying bio-Z by employing robust and power-efficient low-gain IAs and sixth-order single-bit bandpass (BP) ΔΣ ADCs. The proposed bio-Z spectroscopy interface is implemented in a 180 nm CMOS process, consumes 344.3 - 479.3 µW, and occupies 5.4 mm2 area. Measurement results show 0.7 m Ω/√{Hz} sensitivity at 15.625 kHz, 105.8 dB SNR within 4 Hz bandwidth, and a 146.5 dB figure-of-merit. Additionally, recording of EIM in time and frequency domain during contractions of the bicep brachii muscle demonstrates the potential of the proposed bio-Z interface for wearable EIM systems.

A battery-less implantable glucose sensor based on electrical impedance spectroscopy.

The ability to perform accurate continuous glucose monitoring without blood sampling has revolutionised the management of diabetes. Newer methods that can allow measurements during longer periods are necessary to substantially improve patients' quality of life. This paper presents an alternative method for glucose monitoring which is based on electrical impedance spectroscopy. A battery-less implantable bioimpedance spectroscope was designed, built, and used in an in vivo study on pigs. After a recovery period of 14 days post surgery, a total of 236 subcutaneous bioimpedance measurements obtained from intravenous glucose tolerance tests, with glucose concentration ranges between 77.4 and 523.8 mg/dL, were analyzed. The results show that glucose concentrations estimated by subcutaneous bioimpedance measurements correlate very well to the blood glucose reference values. The pigs were clinically healthy throughout the study, and the postmortem examinations revealed no signs of adverse effects related to the sensor. The implantation of the sensor requires minor surgery. The implant, being externally powered, could in principle last indefinitely. These encouraging results demonstrate the potential of the bioimpedance method to be used in future continuous glucose monitoring systems.

A comparative analysis between Mexican and Chinese health systems / Un análisis comparativo entre los sistemas de salud de México y China

Abstract Objective: The comparative network analysis of national health macrosystems is an area whose academic development has not reached due relevance if its influence on decision-making related to the design of public health policies is considered; the establishment of comparative elements between two socially, economically and culturally distant countries, such as Mexico and China, is a complex process given the difficulty of locating equivalent evaluation indicators among some of its elements. Materials and methods: The present work reflects on the similarities and dissimilarities between the national health systems, with an impact on the care provided to the most vulnerable population segments, applying a comparative nodes and networks analysis considering social and economic factors. Results: The network analysis shows that, for practical purposes, the nodes considered in the Mexican health system is superior to those nodes identified in the Chinese health system in terms of quality, mainly in nodes such as convenience of the location, using cutting-edge technology in health institutions and the skill and competence of medical personnel; conversely, the Chinese system is superior to the Mexican in terms of efficiency, mainly involuntary co-payment insurance systems to reduce the catastrophic health expenditure of the vulnerable rural population. Conclusions: The conclusions drawn may serve for subsequent studies to identify opportunities for improvement, correlations and/or trends that could be implemented in the Mexican health system, once the pertinent feasibility studies have been carried out.

Resumen Objetivo: El análisis de redes comparativo de macrosistemas nacionales de salud es un ámbito cuyo desarrollo académico no ha alcanzado la relevancia debida si se considera su influencia en la toma de decisiones relativas al diseño de políticas de salud pública. Así, el establecimiento de elementos comparativos entre dos países social, económica y culturalmente distantes, como México y China, es un proceso complejo dada la dificultad de ubicar indicadores equivalentes de evaluación entre algunos de sus elementos. Materiales y método: El presente trabajo reflexiona sobre las similitudes y diferencias entre los mencionados sistemas nacionales de salud, con incidencia en la atención que se brinda a los segmentos poblacionales más vulnerables, aplicando un análisis comparativo de nodos y redes considerando factores sociales y económicos. Resultados: El análisis de red muestra que, para efectos prácticos, los nodos considerados en el sistema de salud mexicano son superiores a los nodos identificados en el sistema de salud chino en términos de calidad, principalmente en nodos como conveniencia de la ubicación, utilizando tecnología de punta en instituciones de salud y la habilidad y competencia del personal médico; Por el contrario, el sistema chino es superior al mexicano en términos de eficiencia, principalmente sistemas de seguro de copago involuntario para reducir el gasto catastrófico en salud de la población rural vulnerable. Conclusiones: Las conclusiones extraídas podrán servir a estudios posteriores para identificar oportunidades de mejora, correlaciones y/o tendencias que pudieran implementarse en el sistema mexicano de salud, una vez efectuados los estudios de viabilidad pertinentes.

Architectural anatomy of the human tibialis anterior presents morphological asymmetries between superficial and deep unipennate regions.

The tibialis anterior muscle plays a critical role in human ambulation and contributes to maintaining the upright posture. However, little is known about its muscle architecture in males and females. One hundred and nine physically active males and females were recruited. Tibialis anterior muscle thickness, pennation angle, and fascicle length were measured at rest in both unipennate regions of both legs using real-time ultrasound imaging. A linear mixed model was used with muscle thickness, pennation angle, or fascicle length as the dependent variables. All models were carried out with and without total leg lean mass and shank length as covariates. Causal mediation analysis was computed to explore the effect of muscle thickness on the relationship between fascicle length and pennation angle. There were no significant differences between dominant and nondominant legs regarding muscle architecture. Muscle thickness and pennation angle were greater in the deep than the superficial unipennate region in males (1.9 mm and 1.1°, p < 0.001) and women (3.4 mm and 2.2°, p < 0.001). However, the fascicle length was similar in both regions for both sexes. The differences remained significant after accounting for differences in leg lean mass and shank length. In both regions, muscle thickness was 1-3 mm greater in males and superficial pennation angle 2° smaller in females (both, p < 0.001). After accounting for leg lean mass and shank length, sex differences remained for muscle thickness (1.6 mm, p < 0.05) and pennation angle (3.4°, p < 0.001) but only in the superficial region. In both regions, leg lean mass and shank-adjusted fascicle length were 1.4 mm longer in females than males (p < 0.05). The causal mediation analysis revealed that the estimation of fascicle length was positive, suggesting that a 10% increase in muscle thickness would augment the fascicle length, allowing a 0.38° pennation angle decrease. Moreover, the pennation angle increases in total by 0.54° due to the suppressive effect of the increase in fascicle length. The estimated mediation, direct, and total effects were all significantly different from zero (p < 0.001). Overall, our results indicate that the architectural anatomy of the tibialis anterior shows sexual dimorphism in humans. Tibialis anterior presents morphological asymmetries between superficial and deep unipennate regions in both sexes. Lastly, our causal mediation model identified a suppressive effect of fascicle length on the pennation angle, suggesting that increments in muscle thickness are not always aligned with increments in fascicle length or the pennation angle.

Fast Detection and Quantification of Interictal Spikes and Seizures in a Rodent Model of Epilepsy Using an Automated Algorithm.

The electroencephalogram (EEG) is a powerful tool for analyzing neural activity in various neurological disorders, both in animals and in humans. This technology has enabled researchers to record the brain's abrupt changes in electrical activity with high resolution, thus facilitating efforts to understand the brain's response to internal and external stimuli. The EEG signal acquired from implanted electrodes can be used to precisely study the spiking patterns that occur during abnormal neural discharges. These patterns can be analyzed in conjunction with behavioral observations and serve as an important means for accurate asses sment and quantification of behavioral and electrographic seizures. Numerous algorithms have been developed for the automated quantification of EEG data; however, many of these algorithms were developed with outdated programming languages and require robust computational hardware to run effectively. Additionally, some of these programs require substantial computation time, reducing the relative benefits of automation. Thus, we sought to develop an automated EEG algorithm that was programmed using a familiar programming language (MATLAB), and that could run efficiently without extensive computational demands. This algorithm was developed to quantify interictal spikes and seizures in mice that were subjected to traumatic brain injury. Although the algorithm was designed to be fully automated, it can be operated manually, and all the parameters for EEG activity detection can be easily modified for broad data analysis. Additionally, the algorithm is capable of processing months of lengthy EEG datasets in the order of minutes to hours, reducing both analysis time and errors introduced through manual-based processing.

A 57-year-old man with painful ophthalmoplegia and cavernous sinus involvement: Why this is not Tolosa-Hunt syndrome.

Tolosa-Hunt syndrome (THS) is an idiopathic condition included in the differential diagnosis of painful ophthalmoplegia. Although this was once a common diagnosis, the increasing availability of tests reveals an alternative etiology in many cases. Exclusion of treatable disorders is important, because the prognosis may otherwise be poor. We here describe a patient who presented with painful ophthalmoplegia with an infiltrating lesion in the cavernous sinus. Initially suspected of THS, he had a fatal evolution, and postmortem evaluation revealed cervicocephalic actinomycosis. Actinomycosis diagnosis is often missed, and still represents a challenge to the clinician. We highlight pearls and pitfalls to establish a proper diagnosis to avoid missing a treatable condition in patients with suspected THS.

A Finite Element Analysis and Circuit Modelling Methodology for Studying Electrical Impedance Myography of Human Limbs.

OBJECTIVE: Electrical impedance myography (EIM) measures bioimpedance over muscles. This paper proposes a circuit-based modelling methodology originated from finite element analysis (FEA), to emulate tissues and effects from anthropometric variations, and electrode placements, on EIM measurements. The proposed methodology is demonstrated on the upper arms and lower legs. METHODS: FEA evaluates impedance spectra (Z-parameters), sensitivity, and volume impedance density for variations of subcutaneous fat thickness (t f), muscle thickness (t m), and inter-electrode distance (IED), on limb models over 1Hz-1 MHz frequency range. The limbs' models are based on simplified anatomical data and dielectric properties from published sources. Contributions of tissues to the total impedance are computed from impedance sensitivity and density. FEA Z-parameters are imported into a circuit design environment, and used to develop a three Cole dispersion circuit-based model. FEA and circuit model simulation results are compared with measurements on ten human subjects. RESULTS: Muscle contributions are maximized at 31.25 kHz and 62.5 kHz for the upper arm and lower leg, respectively, at 4 cm IED. The circuit model emulates variations in t f and t m, and simulates up to 89 times faster than FEA. The circuit model matches subjects measurements with RMS errors and , while FEA does with and . CONCLUSIONS: We demonstrate that FEA is able to estimate the optimal frequencies and electrode placements, and circuit-based modelling can accurately emulate the limbs' bioimpedance. SIGNIFICANCE: The proposed methodology facilitates studying the impact of biophysical principles on EIM, enabling the development of future EIM acquisition systems.

Acute Mechanical, Neuromuscular, and Metabolic Responses to Different Set Configurations in Resistance Training.

ABSTRACT: Piqueras-Sanchiz, F, Cornejo-Daza, PJ, Sánchez-Valdepeñas, J, Bachero-Mena, B, Sánchez-Moreno, M, Martín-Rodríguez, S, García-García, Ó, and Pareja-Blanco, F. Acute mechanical, neuromuscular, and metabolic responses to different set configurations in resistance training. J Strength Cond Res 36(11): 2983-2991, 2022-The aim of this study was to investigate the effect of set configuration on mechanical performance, neuromuscular activity, metabolic response, and muscle contractile properties. Sixteen strength-trained men performed 2 training sessions in the squat exercise consisting of (a) 3 sets of 8 repetitions with 5 minutes rest between sets (3 × 8) and (b) 6 sets of 4 repetitions with 2 minutes rest between sets (6 × 4). Training intensity (75% one repetition maximum), total volume (24 repetitions), total rest (10 minutes), and training density were equalized between protocols. A battery of tests was performed before and after each protocol: (a) tensiomyography (TMG), (b) blood lactate and ammonia concentration, (c) countermovement jump, and (d) maximal voluntary isometric contraction in the squat exercise. Force, velocity, and power output values, along with electromyography data, were recorded for every repetition throughout each protocol. The 6 × 4 protocol resulted in greater mechanical performance (i.e., force, velocity, and power) and lower neuromuscular markers of fatigue (i.e., lower root mean square and higher median frequency) during the exercise compared with 3 × 8, particularly for the last repetitions of each set. The 3 × 8 protocol induced greater lactate and ammonia concentrations, greater reductions in jump height, and greater impairments in TMG-derived velocity of deformation after exercise than 6 × 4. Therefore, implementing lower-repetition sets with shorter and more frequent interset rest intervals attenuates impairments in mechanical performance, especially in the final repetitions of each set. These effects may be mediated by lower neuromuscular alterations, reduced metabolic stress, and better maintained muscle contractile properties.

Angiotensin-Converting Enzyme 2 (SARS-CoV-2 receptor) expression in human skeletal muscle.

The study aimed to determine the levels of skeletal muscle angiotensin-converting enzyme 2 (ACE2, the SARS-CoV-2 receptor) protein expression in men and women and assess whether ACE2 expression in skeletal muscle is associated with cardiorespiratory fitness and adiposity. The level of ACE2 in vastus lateralis muscle biopsies collected in previous studies from 170 men (age: 19-65 years, weight: 56-137 kg, BMI: 23-44) and 69 women (age: 18-55 years, weight: 41-126 kg, BMI: 22-39) was analyzed in duplicate by western blot. VO2 max was determined by ergospirometry and body composition by DXA. ACE2 protein expression was 1.8-fold higher in women than men (p = 0.001, n = 239). This sex difference disappeared after accounting for the percentage of body fat (fat %), VO2 max per kg of legs lean mass (VO2 max-LLM) and age (p = 0.47). Multiple regression analysis showed that the fat % (ß = 0.47) is the main predictor of the variability in ACE2 protein expression in skeletal muscle, explaining 5.2% of the variance. VO2 max-LLM had also predictive value (ß = 0.09). There was a significant fat % by VO2 max-LLM interaction, such that for subjects with low fat %, VO2 max-LLM was positively associated with ACE2 expression while as fat % increased the slope of the positive association between VO2 max-LLM and ACE2 was reduced. In conclusion, women express higher amounts of ACE2 in their skeletal muscles than men. This sexual dimorphism is mainly explained by sex differences in fat % and cardiorespiratory fitness. The percentage of body fat is the main predictor of the variability in ACE2 protein expression in human skeletal muscle.

Chronic severe methanol intoxication after repeated mask cleansing due to fear of COVID-19: A new risk of coronaphobia.

BACKGROUND: Disproportionate fear of contracting COVID-19 (coronaphobia) may result in inappropriate use of preventive measures that could, in turn, result in severe harm to the patient. OBJECTIVE: To describe a patient with subacute parkinsonism and cognitive dysfunction and magnetic resonance imaging (MRI) evidence of bilateral deep white matter and basal ganglia damage. CASE PRESENTATION: A 56-year-old female presented with a 4-week history of insomnia, cognitive decline, and parkinsonism. Brain MRI revealed a bilateral lesion of both globus pallidus, deep white matter, and cerebellar hemispheres. Her son reported that, for the previous month, she had been cleaning her facial mask three times a day with a pure methanol solution as a disinfectant due to an intense fear of acquiring COVID-19. Previously, she had used 97% isopropyl alcohol and had inadvertently switched to methanol. After the exposure ended, she slowly improved but 4 months later she remains severely disabled. CONCLUSIONS: The repeated exposure to methanol vapor, the MRI findings, and the absence of other etiologies for her cognitive and parkinsonian features led to the diagnosis of chronic methanol intoxication with severe central nervous system damage. Misinformation is a likely contributory factor to such scenario. Efforts should be made by the scientific community to educate the general public on avoiding self-damaging behaviors as a result of coronaphobia.

Efecto del termofosfato sobre el crecimiento y producción de papa (Solanum tuberosum L.) / Effect of thermophosphate on the growth and production of potatoes (Solanum tuberosum L.)

RESUMEN El cultivo de papa es uno de los más representativos de los Andes colombianos. El cultivo tiene altos costos de producción, entre los cuales, la fertilización representa un 36% del total. Los avances tecnológicos en nutrición vegetal han permitido el desarrollo de nuevos compuestos, que generan una mayor asimilación y disponibilidad de los elementos nutritivos, durante los periodos productivos. Dentro de las diferentes fuentes de fósforo empleadas en Colombia, está como alternativa, el termofosfato o fosfato térmico. Por esto, el objetivo del presente trabajo fue evaluar la aplicación del termofosfato en el cultivo de papa variedad 'Superior', en condiciones de campo, en el municipio de Villa Pinzón, Cundinamarca. Se empleó un diseño completamente al azar, con 4 tratamientos, que correspondieron a diferentes porcentajes de fosfato térmico 100% fosfato diamónico (DAP) (manejo convencional); 80% DAP, 20% fosfato térmico (FT); 40% DAP, 60% FT y 20% DAP, 80% FT, (0, 300, 600 y 900kg ha-1), con tres réplicas, para un total de 12 unidades experimentales. Las variables evaluadas fueron pesos fresco y seco, de parte área y raíz, concentración de fósforo en tejido y rendimiento por calidades y total. Se observó que la aplicación de termofosfato en diferentes concentraciones generó un efecto positivo con diferencias estadísticas (P≤0,05), en todas las variables evaluadas. El tratamiento de 600kg ha-1 de termofosfato, se muestra como una alternativa para el aporte de fósforo dentro de los planes de fertilización, en busca de una mejor respuesta fisiológica y productiva del cultivo de papa.

ABSTRACT Potato cultivation is one of the most representative activities of the Colombian Andes. The crop has high production costs, among which fertilization represents 36% of the total Technological advances in plant nutrition have allowed the development of new compounds that generate greater assimilation and availability of nutritional elements during productive periods. Within the different phosphorus sources available in Colombia, thermophosphate exists as an alternative. For this reason, the objective of this research was to evaluate the application of thermophosphate in the potato crop, Superior 'variety, under field conditions in the municipality of Villa Pinzón-Cundinamarca. A completely randomized design was used with 4 treatments that corresponded to different percentages of thermal phosphate: 100% diammonium phosphate (DAP) (conventional management); 80% DAP, 20% thermal phosphate (TF); 40% DAP, 60% TF and 20% DAP, 80% TF (0, 300, 600 y 900kg ha-1), with three replicas for a total of 12 experimental units. The variables evaluated were fresh and dry weights of areal and root part, phosphorus concentration in tissue and yield by qualities and the total. It was observed that the application of thermophosphate at different concentrations generated a positive effect, statistically different (P≤0.05) in all the variables evaluated. Thermophosphate, at 600kg ha-1 was found to be an alternative for the contribution of phosphorus within the fertilization plans, in search of a better physiological and productive response of the potato crop.

Regulation of Nrf2/Keap1 signalling in human skeletal muscle during exercise to exhaustion in normoxia, severe acute hypoxia and post-exercise ischaemia: Influence of metabolite accumulation and oxygenation.

The Nrf2 transcription factor is induced by reactive oxygen and nitrogen species and is necessary for the adaptive response to exercise in mice. It remains unknown whether Nrf2 signalling is activated by exercise in human skeletal muscle. Here we show that Nrf2 signalling is activated by exercise to exhaustion with similar responses in normoxia (PIO2: 143 mmHg) and severe acute hypoxia (PIO2: 73 mmHg). CaMKII and AMPKα phosphorylation were similarly induced in both conditions. Enhanced Nrf2 signalling was achieved by raising Nrf2 total protein and Ser40 Nrf2 phosphorylation, accompanied by a reduction of Keap1. Keap1 protein degradation is facilitated by the phosphorylation of p62/SQSTM1 at Ser349 by AMPK, which targets Keap1 for autophagic degradation. Consequently, the Nrf2-to-Keap1 ratio was markedly elevated and closely associated with a 2-3-fold increase in Catalase protein. No relationship was observed between Nrf2 signalling and SOD1 and SOD2 protein levels. Application of ischaemia immediately at the end of exercise maintained these changes, which were reverted within 1 min of recovery with free circulation. While SOD2 did not change significantly during either exercise or ischaemia, SOD1 protein expression was marginally downregulated and upregulated during exercise in normoxia and hypoxia, respectively. We conclude that Nrf2/Keap1/Catalase pathway is rapidly regulated during exercise and recovery in human skeletal muscle. Catalase emerges as an essential antioxidant enzyme acutely upregulated during exercise and ischaemia. Post-exercise ischaemia maintains Nrf2 signalling at the level reached at exhaustion and can be used to avoid early post-exercise recovery, which is O2-dependent.

Anterior tibialis artery pseudoaneurysm after minimally invasive plate osteosynthesis in the proximal tibia: a case report.

Tibial plateau fractures are common fractures associated with high-energy trauma. The treatment of these fractures remains a challenge today. Recent management of fractures has moved from open surgery toward minimally invasive surgery to reduce complications and improve functional outcomes. Nevertheless, such a minimalistic approach makes visualization of neurovascular structures difficult, placing them at risk. We report the case of a 39-year-old male who developed a pseudoaneurysm of the anterior tibial artery following minimally invasive plate osteosynthesis of the right proximal tibia. Diagnosis was made through noninvasive duplex ultrasound and was referred to endovascular service. Understanding of the anatomy of the surgical site is vital to minimize complications. In addition, proper postsurgical patient evaluation is important to monitor the insurgence of such complications.

Mechanomyographic Measures of Muscle Contractile Properties are Influenced by Electrode Size and Stimulation Pulse Duration.

The aim was to determine the effects of changing pulse duration and electrode size on muscle contractile properties. Thirty-six healthy young male participated in the study (age 24.8 ± 5.8 years; height 178.2 ± 0.6 cm; body mass 71.8 ± 7.3 kg; self-reported weekly moderate intensity activity 3.5 ± 1.2 h·week-1). Tensiomyography was used to assess rectus femoris (RF) and vastus medialis (VM) muscles neuromuscular properties of the dominant leg according to the electrode size (3.2-5 cm) and the stimulus length (0.2, 0.5, and 1 ms). Maximal radial displacement (Dm); Contraction time (Tc); Delay time (Td); Sustained time (Ts) and Half relaxation time (Tr) were measured. Relative and absolute reliability was quantified. To analyze the effects of the electrode and the stimulus length, a repeated-measures analysis of variance was used. Dm and Tc parameters showed for both muscles an excellent relative (0.95-0.99) and absolute reliability (1.6-4.2%). However, Ts and Tr showed low values of absolute reliability (4.4-40.9%). The duration of the stimulus length applied to the RF and VM and electrode size significantly influences muscle's contractile properties (p < 0.05; η2p = 0.09-0.60). The Dm increases substantially as the duration of the stimulus increases and with the use of the larger electrode in both muscles. However, Tc and Td are less affected by both conditions and not entirely clear. Practically, our study suggests that a stimulus pulse duration of 1 ms together with a 5 × 5 cm electrode is necessary to reach a reliable and reproducible assessment of both RF and VM muscles contractile properties.

An integrative approach to the regulation of mitochondrial respiration during exercise: Focus on high-intensity exercise.

During exercise, muscle ATP demand increases with intensity, and at the highest power output, ATP consumption may increase more than 100-fold above the resting level. The rate of mitochondrial ATP production during exercise depends on the availability of O2, carbon substrates, reducing equivalents, ADP, Pi, free creatine, and Ca2+. It may also be modulated by acidosis, nitric oxide and reactive oxygen and nitrogen species (RONS). During fatiguing and repeated sprint exercise, RONS production may cause oxidative stress and damage to cellular structures and may reduce mitochondrial efficiency. Human studies indicate that the relatively low mitochondrial respiratory rates observed during sprint exercise are not due to lack of O2, or insufficient provision of Ca2+, reduced equivalents or carbon substrates, being a suboptimal stimulation by ADP the most plausible explanation. Recent in vitro studies with isolated skeletal muscle mitochondria, studied in conditions mimicking different exercise intensities, indicate that ROS production during aerobic exercise amounts to 1-2 orders of magnitude lower than previously thought. In this review, we will focus on the mechanisms regulating mitochondrial respiration, particularly during high-intensity exercise. We will analyze the factors that limit mitochondrial respiration and those that determine mitochondrial efficiency during exercise. Lastly, the differences in mitochondrial respiration between men and women will be addressed.

Supplementation with a Mango Leaf Extract (Zynamite®) in Combination with Quercetin Attenuates Muscle Damage and Pain and Accelerates Recovery after Strenuous Damaging Exercise.

Prolonged or unusual exercise may cause exercise-induced muscle damage (EIMD). To test whether Zynamite®, a mango leaf extract rich in the natural polyphenol mangiferin, administered in combination with quercetin facilitates recovery after EIMD, 24 women and 33 men were randomly assigned to two treatment groups matched by sex and 5 km running performance, and ran a 10 km race followed by 100 drop jumps to elicit EIMD. One hour before the competition, and every 8 hours thereafter for 24 hours, they ingested placebo (728 mg of maltodextrin) or 140 mg of Zynamite® combined with 140 mg of quercetin (double-blind). Although competition times were similar, polyphenol supplementation attenuated the muscle pain felt after the competition (6.8 ± 1.5 and 5.7 ± 2.2 a.u., p = 0.035) and the loss of jumping performance (9.4 ± 11.5 and 3.9 ± 5.2%, p = 0.036; p = 0.034) and mechanical impulse (p = 0.038) 24 hours later. The polyphenols attenuated the increase of serum myoglobin and alanine aminotransferase in men, but not in women (interaction p < 0.05). In conclusion, a single dose of 140 mg Zynamite® combined with 140 mg of quercetin, administered one hour before competition, followed by three additional doses every eight hours, attenuates muscle pain and damage, and accelerates the recovery of muscle performance.

Electromyographic Activity Evolution of Local Twitch Responses During Dry Needling of Latent Trigger Points in the Gastrocnemius Muscle: A Cross-Sectional Study.

OBJECTIVE: Trigger points (TrPs) are hypersensitive spots within taut bands of skeletal muscles that elicit referred pain and motor changes. Among the variety of techniques used for treating TrPs, dry needling is one of the most commonly applied interventions. The question of eliciting local twitch responses (LTRs) during TrP dry needling is unclear. Our main aim was to investigate the evolution of the electromyographic (EMG) peak activity of each LTR elicited during dry needling into latent TrPs of the gastrocnemius medialis muscle. METHODS: Twenty asymptomatic subjects with latent TrPs in the gastrocnemius medialis muscle participated in this cross-sectional study. Changes in EMG signal amplitude (root mean square [RMS]) with superficial EMG were assessed five minutes before, during, and five minutes after dry needling. The peak RMS score of each LTR was calculated (every 0.5 sec). RESULTS: Analysis of variance revealed a significant effect (F = 29.069, P <0.001) showing a significant decrease of RMS peak amplitude after each subsequent LTR. Differences were significant (P <0.001) during the first three LTRs, and stable until the end of the procedure. No changes (P =0.958) were found for mean RMS data at rest before (mean = 65.2 mv, 95% confidence interval [CI] = 47.3-83.1) and after (61.0 mv, 95% CI = 42.3-79.7) dry needling. CONCLUSIONS: We found that, in a series of LTRs elicited during the application of dry needling over latent TrPs in the medial gastrocnemius muscle, the RMS peak amplitude of each subsequent LTR decreased as compared with the initial RMS peak amplitude of previous LTRs. No changes in superficial EMG activity at rest were observed after dry needling of latent TrPs of the gastrocnemius medialis muscle.