RESUMEN

INTRODUCTION: Ventricular assist devices represent a treatment option for patients with advanced heart failure, offering control over various haemodynamic variables. Similarly, the prescription of exercise within a cardiac rehabilitation programme for heart failure patients is recommended to reduce symptoms, and hospitalisations, improve cardiorespiratory fitness, and increase exercise tolerance. Therefore, exercise prescription can impact those with ventricular assist devices. Given the limited evidence on exercise-based cardiac rehabilitation programmes for this population, this review aims to describe the most commonly used strategies and their health benefits when physical exercise is included in a cardiac rehabilitation programme for patients with ventricular assist devices. MATERIALS AND METHODS: An exploratory review was conducted through searches in the databases: PubMed, SCOPUS, PeDro, and ScienceDirect. The search was limited to studies published between 2013 and 2023. Filters were applied independently by title, abstract, and full text. The included articles were analysed based on the description of the types of cardiac rehabilitation strategies used in patients with ventricular assist devices. RESULTS: Seven articles were included. Each programme employed a cardiopulmonary exercise test before prescribing physical exercise. The most commonly used strategy was aerobic exercise, predominantly high-intensity interval training (HIIT) with intensities close to 90% of peak VO2, followed by continuous moderate-intensity exercise. Limb strength exercises were included in three programmes. CONCLUSIONS: The analysed literature suggests that cardiac rehabilitation in patients with ventricular assist devices is safe and can provide benefits in cardiorespiratory fitness and exercise tolerance. High-intensity interval training is identified as an appropriate strategy for achieving results, offering short-term improvements.

Asunto(s)

RESUMEN

RESUMEN Las enfermedades cardiovasculares y el cáncer corresponden a la primera y segunda causa de muerte a nivel mundial, respectivamente. Comparten factores de riesgo comunes: envejecimiento, estilos de vida no saludables, entre otros; con la atenuante que los pacientes con cáncer o sobrevivientes a este, por sus tratamientos, pueden desarrollar cardiotoxici- dad. Por lo tanto, las estrategias de prevención y tratamiento en algunos de sus abordajes también son similares. Pueden considerarse enfermedades simultáneas o consecutivas, pueden coexistir en un mismo paciente, corresponde entonces un abordaje multidisciplinario, basado en evaluación del riesgo, entrenamiento físico, optimización de terapia farmacoló- gica, consejería de estilos de vida saludable, control de factores de riesgo cardiovascular, apoyo psicológico, adherencia a un estilo de vida más activo con la consecuente mejora en la capacidad cardiopulmonar y por lo tanto funcional. Este documento tiene la intención de plantear una propuesta de protocolo para la prescripción de ejercicio en paciente on- cológico o sobreviviente de cáncer para la prevención de enfermedad cardiovascular, basado en recomendaciones de los consensos internacionales.

ABSTRACT Protocol proposal for exercise prescription in cancer patients or cancer survivors for the prevention of cardiovascular disease Cardiovascular diseases and cancer correspond to the first and second causes of death worldwide. They share common risk factors: aging, unhealthy lifestyles, among others; with the attenuating circumstance that cancer patients or survivors may develop cardiotoxicity due to their treatment. Therefore, the prevention and treatment strategies in some of its approaches are also similar. Diseases can be considered simultaneous or consecutive, they can coexist in the same patient, so a multidisciplinary approach is appropriate, based on risk assessment, physical training, optimization of drug therapy, healthy lifestyle counseling, control of cardiovascular risk factors, psychological support, adherence to a more active lifestyle with the consequent improvement in cardiopulmonary and therefore functional capacity. This document intends to propose a protocol proposal for the prescription of exercise in cancer patients or cancer survivors for the prevention of cardiovascular disease, based on international consensus recommendations.

Asunto(s)

RESUMEN

Chronic obstructive pulmonary disease (COPD) patients manifest muscle dysfunction and impaired muscle oxidative capacity, which result in reduced exercise capacity and poor health status. This study examined the effects of 12-week eccentric (ECC) and concentric (CONC) cycling training on plasma markers of cardiometabolic health, oxidative stress, and inflammation in COPD patients. A randomized trial in which moderate COPD was allocated to ECC (n = 10; 68.2 ± 10.0 year) or CONC (n = 10; 71.1 ± 10.3 year) training groups. Participants performed 12-week ECC or CONC training, 2-3 sessions per week, 10 to 30 min per session. Before and after training, peak oxygen consumption, maximal power output (VO2peak and POmax), and time-to-exhaustion (TTE) tests were performed. Plasma antioxidant and oxidative markers, insulin resistance, lipid profile, and systemic inflammation markers were measured before and after training at rest. VO2peak, POmax and TTE remained unchanged after ECC and CONC. CONC induced an increase in antioxidants (p = 0.01), while ECC decreased antioxidant (p = 0.02) markers measured at rest. CONC induced lesser increase in oxidative stress following TTE (p = 0.04), and a decrease in insulin resistance (p = 0.0006) compared to baseline. These results suggest that CONC training induced an increase in insulin sensitivity, antioxidant capacity at rest, and lesser exercise-induced oxidative stress in patients with moderate COPD.

Asunto(s)

RESUMEN

INTRODUCTION: Faced with lockdowns, it was mandatory the development of supervised home-based RT protocols to keep patients with chronic kidney disease engaged in programs. Nonetheless, there is a lack of scientific literature regarding its effects on patients. PURPOSE: To investigate the effects of a supervised home-based progressive resistance training program on functional performance, bone mineral density, renal function, endothelial health, inflammation, glycemic homeostasis, metabolism, redox balance, and the modulation of exerkines in patients with CKD in stage 2. METHODS: Patients (n = 31) were randomized and allocated into the control group (CTL; n = 15; 58.07 ± 5.22 yrs) or resistance training group (RT; n = 16; 57.94 ± 2.74 yrs). RT group performed 22 weeks of supervised progressive home-based resistance exercises. Bone mineral density, anthropometric measurements, and functional performance were assessed. Venous blood samples were collected at baseline and after the intervention for the analysis of markers of renal function, endothelial health, inflammation, glycemic homeostasis, metabolism, and redox balance. RESULTS: Twenty-two weeks of home-based RT were effective in improving (P < 0.05) functional performance, bone mineral density, uremic profile, ADMA, inflammatory markers, the Klotho-FGF23 axis, glycemic homeostasis markers, and exerkines. These improvements were accompanied by higher concentrations of exerkines and anti-inflammatory cytokines. RT group displayed a decrease in cases of osteopenia after the intervention (RT: 50 % vs. CTL: 86.7 %; X2 = 4.763; P = 0.029). CONCLUSION: Results provide new evidence that supervised home-based progressive RT may be a relevant intervention to attenuate the progression of CKD and improve functional capacity, bone mineral density, and the immunometabolic profile. These improvements are associated with positive modulation of several exerkines.

Asunto(s)

RESUMEN

Looped elastic bands around the thigh are commonly used during squats and result in increased hip activation. Due to the closed kinetic chain nature of the squat exercise, one may expect that placing the elastic band on distal segments, close to the floor contact, may not result in the same increase in hip muscle activation as that achieved with a looped band around the thigh. We analyzed the effects of band position (thigh, lower leg, and forefoot) and band stiffness on the myoelectric activity of the tensor fascia latae, gluteus medius, gluteus maximus, biceps femoris, vastus medialis, and vastus lateralis during squats in 35 healthy subjects (18 men and 17 women). The greatest myoelectric activity of hip muscles was observed when the stiffest band was positioned around the forefeet with an increase in 24% for the tensor fascia latae, 83% for the gluteus medius, and 68% for the gluteus maximus compared to free (without resistance band) squatting. Contrary to previous thinking, the use of elastic bands around the forefeet during squats can elicit increased myoelectric activity of hip muscles, with a magnitude often greater than when the band is placed around the thigh segments.

RESUMEN

la inactividad física es un estilo de vida que se ha venido acoplando de manera significativa en la población durante los últimos años y el compromiso cardiovascular inherente a esta falta de actividad es uno de los factores de riesgo más grandes que deben enfrentar los profesionales de la salud. Desde la consulta al médico de atención primaria realizar una adecuada prescripción del ejercicio en el adulto sano puede maximizar los múltiples beneficios de la actividad física y reducir el riesgo cardiovascular y los factores que puedan contribuir al desarrollo de diversas enfermedades crónicas no transmisibles. Objetivo y metodología: con el fin de orientar al profesional de la salud en este proceso de prescripción de una manera adecuada y fundamentada se realiza una revisión de la literatura sobre los conceptos básicos de la actividad física y el ejercicio, el principio Frecuencia, Intensidad, Tiempo y Tipo (FITT), el método de abordaje del paciente y la estructuración de un plan básico de ejercicio que cumpla con las recomendaciones estipuladas por la Organización Mundial de la Salud. Conclusión: la promoción de la actividad física de manera correcta por medio de la comprensión de conceptos relacionados para la prescripción del ejercicio permitirá a los médicos de atención primaria contribuir activa y acertadamente a los Objetivos de Desarrollo Sostenible estipulados para 2030 desde la salud y el bienestar.

Physical inactivity is a lifestyle that has significantly increased in the population in recent years. The cardiovascular compromise inherent to this lack of activity is one of the greatest risk factors that health professionals must face. From the primary care physician's office, appropriate exercise prescription in healthy adults can maximize the multiple benefits of physical activity and reduce cardiovascular risk and the factors that may contribute to the development of various chronic non- communicable diseases.

A inatividade física é um estilo de vida que vem aumentando significativamente na população nos últimos anos, e o comprometimento cardiovascular inerente a essa falta de atividade é um dos maiores fatores de risco que os profissionais de saúde devem abordar. A prescrição adequada de exercícios em adultos saudáveis pode maximizar os múltiplos benefícios da atividade física e reduzir o risco cardiovascular e os fatores que podem contribuir para o desenvolvimento de várias doenças crónicas não transmissíveis.

Asunto(s)

RESUMEN

Resumen La insuficiencia cardiaca (IC) es una patología cardiovascular con elevada morbi-mortalidad, sus causas más frecuentes se asocian a la cardiopatía isquémica y la hipertensión arterial. La rehabilitación cardiaca (RC) ha demostrado ser efectiva para mejorar la sintomatología, la capacidad funcional, el número de internamientos y la mortalidad en personas con dicha enfermedad. A pesar de esto, se ha documentado que la RC y el ejercicio físico como uno de sus componentes, siguen siendo subutilizados. Se revisa la evidencia científica y guías de práctica clínica disponibles, con el objetivo de valorar la seguridad, la respuesta y los beneficios del ejercicio en personas con IC, incluyendo las recomendaciones sobre prescripción, modalidades de entrenamiento (HIIT, músculos respiratorios y electroestimulación muscular funcional) y finalmente las consideraciones especiales durante el proceso de RC.

Abstract Exercise prescription in patients with heart failure during cardiac rehabilitation. Heart Failure (HF) is a cardiovascular disease with high morbidity and mortality. The most frequent causes are associated with ischemic heart disease and high blood pressure. Cardiac rehabilitation (CR) has been shown to be an effective method in improving symptoms, functional capacity, also in reduce of the number of hospitalizations and mortality in people with this disease. Despite this, it has been documented that CR and physical exercise continue to be underused. The scientific evidence and available clinical practice guidelines are reviewed, in order to assess the safety, response, and benefits of exercise in people with HF, including recommendations on prescription, training modalities (HIIT, respiratory muscles, and functional muscle electrostimulation) and finally the special considerations during the CR process.

Asunto(s)

RESUMEN

Session ratings of perceived exertion (sRPE) are considered a practical marker of whole session exercise intensity, but its relationship to exercise volume has remained unclear. We analyzed the effects of exercise duration at different intensities on overall and differentiated sRPE. Sixteen males (Mage = 22.6, SD = 2.2 years; Mheight = 176.4, SD = 5.8 cm; Mweight = 74.0, SD = 5.9 kg; and Mbody fat = 9.4, SD = 2.2%) performed 15 and 30 minute runs at speeds associated with RPE levels of two (weak), three (moderate) and five (strong) on Borg's CR-10 scale during a previous graded exercise test. We used Foster's scale to access sRPE 30 minutes after each trial. Significant increases in sRPE were found with increases in running speed (p < 0.01, ηG2 = 0.48) and duration (p < 0.01, ηG2 = 0.16), with a significant speed X duration interaction (p < 0.01, ηG2 = 0.10). In addition, there was a significant effect for sRPE type (p = 0.01, ηG2 = 0.05) in that overall sRPE was slightly lower than sRPE differentiated to legs and higher than sRPE differentiated to breathing through the trials. Changes in sRPE from 15 to 30-minute trials were minimal for the slow speed and weak sRPE (Cohen´s dz = 0.04 - 0.25) but got higher at the moderate (Cohen´s dz = 0.88 - 1.06) and strong (Cohen´s dz = 1.94 - 2.50) speeds and sRPEs. Thus, exercise duration affects sRPE in an intensity dependent manner. This finding has practical relevance for prescribing exercise, suggesting a need to target specific training loads or aims to optimize trainees' retrospective perceptions of the exercise experience.

Asunto(s)

RESUMEN

BACKGROUND: To validate the traditional talk test (TTT) and an alternative talk test (ATT; using a visual analog scale) in overweight/obese (OW-OB) patients and to establish its accuracy in determining the aerobic training zones. METHODS: We recruited 19 subjects aged 34.9 ± 6.7 years, diagnosed with overweight/obesity (BMI 31.8 ± 5.7). Every subject underwent incremental cycloergometric tests for maximal oxygen consumption, and TTT in a randomized order. At the end of each stage during the TTT, each subject read out loud a 40 words text and then had to identify the comfort to talk in two modalities: TTT which consisted in answering "Yes," "I don't know," or "No" to the question Was talking comfortable?, or ATT through a 1 to 10 numeric perception scale (visual analog scale (VAS)). The magnitude of differences was interpreted in comparison to the smallest worthwhile change and was used to determine agreement. RESULTS: There was an agreement between the power output at the VAS 2-3 of ATT and the power output at the ventilatory threshold 1 (VT1) (very likely equivalent; mean difference - 1.3 W, 90% confidence limit (CL) (- 8.2; 5.6), percent chances for higher/similar/lower values of 0.7/99.1/0.2%). Also, there was an agreement between the power output at the VAS 6-7 of ATT and the power output at the ventilatory threshold 2 (VT2) (very likely equivalent; mean difference 11.1 W, 90% CL (2.8; 19.2), percent chances for higher/similar/lower values of 0.0/97.6/2.4%). CONCLUSIONS: ATT is a tool to determine exercise intensity and to establish aerobic training zones for exercise prescription in OW-OB patients.

RESUMEN

Objective: The main purpose of this study was to evaluate whether the %HRR-%VO2R relationship and %HRR-VO2peak relationship are affected in patients with moderate or severe asthma and whether airway obstruction and aerobic capacity influence these relationships.Methods: A linear regression was calculated using the paired %VO2R-%HRR and %VO2peak-%HRR for 93 subjects with asthma. The mean slope and y-intercept were calculated and compared with the line of identity (y-intercept = 0, slope = 1) for all patients and subgroups for the following conditions: low and normal VO2peak and low and normal FEV1.Results: The slope and intercepts of %VO2R-%HRR were similar to the line of identity for all groups (p > 0.05), and the regressions between %HRR and %VO2peak did not coincide with the line of identity for all groups (p < 0.05). There were no associations between the intercepts of the %HRR-VO2peak and the %HRR-%VO2R relationship with the VO2peak (p > 0.05) or FEV1 (p > 0.05).Conclusions: This is the first study to confirm a constant equivalence between %HRR and %VO2R in outpatients with moderate or severe asthma. Our data also suggest that the relationship between %HRR and %VO2peak is unreliable. These results support the use of %HRR in relation to %VO2R to estimate exercise intensity in this population, independently of the pulmonary function and fitness level.

Asunto(s)

RESUMEN

Exercise in cirrhosis of the liver is an emerging topic in hepatology. Despite the known benefits of exercise in the general population, there are currently few studies addressing that issue in relation to cirrhosis and more evidence is still needed. Even though some studies have reported an acute, exercise-induced increase in the hepatic venous pressure gradient (HVPG), the opposite (a decrease in the HVPG) has been shown by recent data after an exercise program carried out for>14 weeks. In addition to that benefit, improvement has been described in the metabolic profile, quality of life, muscle mass, cardiopulmonary function, and nutritional status. Together, those features make exercise in cirrhosis a very attractive intervention. However, certain aspects must be taken into account before prescribing exercise in that population and they include cardiovascular risk, musculoskeletal disorders, and complications related to cirrhosis. After considering those factors, an individually tailored exercise program should be developed for each patient, according to the points stated above and the desired goal. Information about exercise-limiting factors, type of exercise prescribed, monitoring methods, and concomitant nutritional therapy is provided in the present review.

Asunto(s)

RESUMEN

BACKGROUND: Tendinopathies are specific degenerative conditions of the tendon characterized by pain and disability. The most common tendinopathies of the lower limbs are patellar, Achilles, gluteal, and proximal tendinopathy of the hamstring muscles. Exercise therapy has been studied for the treatment of these tendinopathies; however, different types of muscle contraction, exercise, dose, and intensity are found in the literature, which can make choosing the best treatment option difficult. The purpose of this systematic review is to analyze the available evidence about the effectiveness of exercise therapy in the treatment of patients with lower limb tendinopathies and the effects of different types of exercise therapy in the treatment of these patients. METHODS: The search strategy will be performed in the following databases: CENTRAL, MEDLINE, EMBASE, PEDro, SPORTDiscus, and CINAHL. The inclusion criteria of the studies will be randomized controlled trials with patients with one of the following tendinopathies: patellar, Achilles, gluteal, and proximal tendinopathy of the hamstring muscles. The primary outcomes will be pain and disability. The intervention will be exercise therapy, and the comparators will be different types of exercise, control groups, or any other type of intervention. DISCUSSION: Other systematic reviews have been published about the prescription of exercise therapy in the treatment of tendinopathies of the lower limbs. However, the results of these reviews are limited to only one type of tendinopathy or specific exercise. Because some of these reviews are also outdated, this systematic review will investigate whether exercise therapy is more effective than any other type of intervention and if there is a best form of exercise therapy, considering modality, dose, and intensity, for the treatment of lower limb tendinopathies. Furthermore, this study will present data related to the sample size, recruitment period, methodological quality, and visibility of the eligible studies. SYSTEMATIC REVIEW REGISTRATION: PROSPERO ( CRD42018093011 ).

Asunto(s)

RESUMEN

To compare the acute effects of different intra-session exercise sequences and aerobic exercise modalities during concurrent training sessions on oxygen consumption (VO2) and energy expenditure (EE) in young women. Eleven young women volunteered to participate in this study and underwent tests of their dynamic strength and a maximal incremental test on both the treadmill and cycle ergometer. Four concurrent training sessions were performed: resistance-running (RRu), resistance-cycling (RC), running-resistance (RuR) and cycling-resistance (CR). The aerobic exercise lasted 30 minutes and was performed at a heart rate equivalent to 95% of the second ventilatory threshold. The resistance exercise lasted approximately 21 minutes and consisted of 4 sets of 10 RM in each exercise. The VO2 was continuously evaluated through the portable gas analyser. No differences were found in the VO2 between the intra-session exercise sequence independently of aerobic modality (i.e., RRu vs. RuR, and RC vs. CR), and the sessions with the running aerobic exercise showed greater VO2 than sessions using cycling aerobic exercise in both exercise sequences (VO2aerobic (ml · kg-1 · min-1) - RRu: 27.5; RuR: 27.1; RC: 20.2; CR: 20.8). The present study showed that the intra-session exercise sequence during concurrent training does not influence VO2. However, the optimal combination of resistance and aerobic exercise should include running in order to increase VO2 and optimize EE.

RESUMEN

To assess the physical capacity of rats in forced swim tests, the animal should perform a continuous activity (CON) at the surface to avoid apnea. Bobbing movement (BOB), vigorous paddling known as climbing (CLI), and diving activity (DIV) are inadequate swimming patterns known to increase the exercise intensity variability, impairing the test reliability. Thus, the exercise work accomplished and related physiological variables, such as the blood lactate concentration, may be unreproducible in forced swim. This study aimed to verify the exercise work reproducibility in rats with a 30-min test-retest at maximal lactate steady state (MLSS) intensity using a tethered-swimming apparatus that analyzes swimming patterns by the direct measurement of swimming force. Additionally, it was determined the swimming force and duration of CON, BOB, CLI, and DIV at physiologically different exercise-intensities. The swimming force at MLSS (n = 64) was 38 ± 7 gf.Kg-1, while the blood lactate concentration was 4.2 ± 1.6 mmol.L-1. In the test-retest (N = 23), swimming force (36.6 ± 7 gf.Kg-1 vs. 36.4 ± 7 gf.Kg-1) and blood lactate concentration (4.7 ± 1.7 mmol.L-1 vs. 4.2 ± 1.7 mmol.l-1) were similar, but only the swimming force was highly correlated (0.90 and 0.31). Although it was not statistically different, the swimming force for CON tends to be slightly lower than CLI and slightly higher than BOB independently of exercise-intensity. The CON pattern predominates (∼52.8 ± 18%) at intensities below and of MLSS but BOB was the swimming pattern more often observed above MLSS-intensity (52.6 ± 18%). The present study used a tethered swimming apparatus to investigate the reliability of forced swim tests for exercise testing in rats and better understand the swimming patterns when determining the MLSS, but the results can be extended to any study that rely on forced swim for exercise testing and training. The result suggests that, at least at intensities of physiological stability, the exercise work accomplished by rats is reproducible in forced swim, but the blood lactate concentration seems to be affected by other factors, such as the apnea and stress caused by the possibility of drowning, besides the exercise-intensity.

RESUMEN

AIM: Exercise is one of the most important components in frailty prevention and treatment. Therefore, we systematically reviewed the effect of resistance training (RT) alone or combined with multimodal exercise intervention on muscle hypertrophy, maximal strength, power output, functional performance, and falls incidence in physically frail elderly. METHODS: MEDLINE, Cochrane CENTRAL, PEDro, and SPORTDiscus databases were searched from 2005 to 2017. Studies must have mentioned the effects of RT (i.e., included or not in multimodal training) on at least one of the following parameters: muscle mass, muscle strength, muscle power, functional capacity, and risk of falls in frail elderly. RESULTS: The initial search identified 371 studies and 16 were used for qualitative analysis for describing the effect of strength training performed alone or in a multimodal exercise intervention. We observed that RT alone or in a multimodal training may induce increases of 6.6-37% in maximal strength; 3.4-7.5% in muscle mass, 8.2% in muscle power, 4.7-58.1% in functional capacity and risk of falls, although some studies did not show enhancements. CONCLUSION: Frequency of 1-6 sessions per week, training volume of 1-3 sets of 6-15 repetitions and intensity of 30-70%1-RM promoted significant enhancements on muscle strength, muscle power, and functional outcomes. Therefore, in agreement with previous studies, we suggest that supervised and controlled RT represents an effective intervention in frailty treatment.

Asunto(s)

RESUMEN

OBJECTIVE: The purpose of this review was to identify doses of exercise therapy associated with greater treatment effect sizes in individuals with common musculoskeletal disorders of the foot and ankle, namely, achilles tendinopathy, ankle sprains and plantar heel pain. METHODS: AMED, EMBASE and MEDLINE were searched from 2005 to August 2017 for randomized controlled trials related to exercise for these three diagnoses. The Physiotherapy Evidence Database scale was used for methodological quality assessment. Exercise dosing variables and outcome measures related to pain and function were extracted from the studies, and standardized mean differences were calculated for the exercise groups. RESULTS: Fourteen studies met the final inclusion. A majority of the studies showed large effects and two small trends were identified. Patients with plantar heel pain may benefit more from a daily home exercise program than two supervised visits per week (SMD=3.82), but this recommendation is based on weak evidence. In achilles tendinopathy, a relationship was also seen when sets and repetitions of eccentric exercise were performed as tolerated (SMD=1.08 for function, -1.29 for pain). CONCLUSIONS: Session duration, frequency, total number of visits, and overall length of care may all be dosing variables with limited value for determining effective exercise prescription. However, the limited number of studies prevents any definitive conclusions. Further investigation is warranted to improve our understanding of the influence exercise dosing has on treatment effect sizes. Future randomized controlled trials comparing specific exercise dose variables should be conducted to clarify the impact of these variables.

Asunto(s)

RESUMEN

In 1993, Uwe Tegtbur proposed a useful physiological protocol named the lactate minimum test (LMT). This test consists of three distinct phases. Firstly, subjects must perform high intensity efforts to induce hyperlactatemia (phase 1). Subsequently, 8 min of recovery are allowed for transposition of lactate from myocytes (for instance) to the bloodstream (phase 2). Right after the recovery, subjects are submitted to an incremental test until exhaustion (phase 3). The blood lactate concentration is expected to fall during the first stages of the incremental test and as the intensity increases in subsequent stages, to rise again forming a "U" shaped blood lactate kinetic. The minimum point of this curve, named the lactate minimum intensity (LMI), provides an estimation of the intensity that represents the balance between the appearance and clearance of arterial blood lactate, known as the maximal lactate steady state intensity (iMLSS). Furthermore, in addition to the iMLSS estimation, studies have also determined anaerobic parameters (e.g., peak, mean, and minimum force/power) during phase 1 and also the maximum oxygen consumption in phase 3; therefore, the LMT is considered a robust physiological protocol. Although, encouraging reports have been published in both human and animal models, there are still some controversies regarding three main factors: (1) the influence of methodological aspects on the LMT parameters; (2) LMT effectiveness for monitoring training effects; and (3) the LMI as a valid iMLSS estimator. Therefore, the aim of this review is to provide a balanced discussion between scientific evidence of the aforementioned issues, and insights for future investigations are suggested. In summary, further analyses is necessary to determine whether these factors are worthy, since the LMT is relevant in several contexts of health sciences.

RESUMEN

The purpose of the study was to compare elbow flexion peak torque (PT) and fatigue index (FI) during isokinetic concentric contractions in men and women with different training levels. Sixty-eight young men and women were divided into four groups: resistance trained men (RTM), non-resistance trained men (NRTM), resistance trained women (RTW) and non- resistance trained women (NRTW). Participants performed two tests on an isokinetic dynamometer, one to evaluate PT and one to evaluate FI. Significant interactions were found for sex and resistance training status with both PT and FI. In general, resistance-trained subjects had higher PT, and women showed lower PT than men. PT values were 67.12 ± 9.93 N·m for RTM, 49.9 ± 8.5 N·m for NRTM, 41.84 ± 7.52 N·m for RTW, and 26.05 ± 3.34 N·m for NRTW. Separate analysis revealed that RTM had higher PT than all other groups. However, FI was higher for NRTM than for RTM and NRTW and no difference was found between RTM and NRTW. FI was 37.86 ± 10.89 % for RTW, 45.74 ± 13.17 % for NTRW, 45.89 ± 8.24 % for RTM, and 51.92 ± 4.5 % for NRTM. Women produce lower PT, and have a higher fatigue tolerance than men of similar training status. Considering that women showed to be more resistant to fatigue than men, women can manipulate training variables differently from men, such as, including more repetitions at the same relative load or using higher relative loads at the same number of repetitions.

RESUMEN

Abstract: Introduction and objective: Maximum heart rate (MHR) is essential to establish the effort, intensity and strategies for physical activity. For this, there are more than 40 formulas; among the best known are 220-Age and Tanaka. The objective of this research is to determine the validity and effectiveness of the equations for MHR. Material and methods: Observational, descriptive and transversal study with a sample of 300 participants (181 women and 119 men) with a mean age of 26 ± 10 years. For the development of this research, we used anthropometry, vital signs, Borg scale and questionnaire for cardiovascular risk factors and a stress test and compare the data with 25 equations of MHR. Results: Maximum heart rate by stress test of the 300 participants was 179.6 ± 15 beats per minute; regarding 25 equations, was observed an overestimation up to 19 beats per minute. Only the formulas of Morris and Graettinger scored less than 4 beats per minute apart to stress test. Conclusions: No one is recommended equations evaluated for their significant difference in the stress test; especially 220-edad, Hossack y Bruce, Cooper and Lester whose difference mean were above 14 beats per minute (p = 0.000). The equation of Morris (p = 0.380) no were found significant differences and were the most successful to estimate the MHR for a minimum difference compared to a stress test.

Resumen: Introducción y objetivo: La frecuencia cardiaca máxima (FCM) es un parámetro esencial para esTablecer el esfuerzo, intensidad y estrategias de la actividad física. Para ello, existen más de 40 fórmulas; entre las más conocidas son 220-edad y Tanaka. El objetivo de la presente investigación es determinar la validez y efectividad de las ecuaciones para la FCM. Material y métodos: Estudio observacional, descriptivo y transversal con 300 participantes (181 mujeres y 119 hombres), de edad promedio de 26 ± 10 años. Para el desarrollo de esta investigación, se obtuvo antropometría, signos vitales, escala de Borg, cuestionario para factores de riesgo cardiovascular y realización de prueba de esfuerzo para comparar datos con 25 ecuaciones de FCM. Resultados: La FCM por prueba de esfuerzo en los 300 participantes fue de 179.6 ± 15 latidos por minuto; en cuanto a las 25 ecuaciones, se observó una sobreestimación hasta en 19 latidos por minuto y sólo las fórmulas de Morris y Graettinger obtuvieron menos de cuatro latidos por minuto de diferencia a la prueba de esfuerzo. Conclusiones: No se recomienda alguna de las ecuaciones evaluadas por su diferencia significativa respecto a la prueba de esfuerzo; especialmente 220-edad, Hossack y Bruce, Cooper y Lester cuya diferencia de media estuvo por encima de 14 latidos por minutos (p = 0.000). Para la ecuación de Morris (p = 0.380) no se encontraron diferencias significativas y fue la más acertada para estimar la FCM comparada con una prueba de esfuerzo.