Gutiérrez-Vargas, R, Martín-Rodríguez, S, Sánchez-Ureña, B, Rodríguez-Montero, A, Salas-Cabrera, J, Gutiérrez-Vargas, JC, Simunic, B, and Rojas-Valverde, D. Biochemical and muscle mechanical postmarathon changes in hot and humid conditions. J Strength Cond Res XX(X): 000-000, 2018-The aim of this study was to compare biochemical changes and mechanical changes in the lower-limb muscles before and after a marathon race in hot and humid conditions. Eighteen healthy runners participated in a marathon at between 28 and 34° C and 81% humidity in Costa Rica. Serum magnesium (Mg), creatine phosphokinase (CPK), lactate dehydrogenase, and hematocrit (HCT) were measured before and after the marathon. Tensiomyography measurements from the rectus femoris (RF) and vastus medialis, muscle displacement (Dm), contraction time (Tc), and velocities of contraction to 10 and 90% of Dm (V10 and V90) were obtained before and after the marathon. Postrace measurements showed a 544% increase in CPK (t(17): -6.925, p < 0.01), a 16% increase in HCT (t(17): -7.466, p < 0.01), a 29% decrease in Mg (t(17): 3.91, p = 0.001), a 2% decrease in body mass (t(17): 4.162, p = 0.001), a 4% increase in Tc of the RF (t(17): -2.588, p = 0.019), and a 12% increase in Dm of the RF (t(17): -2.131, p < 0.048) compared with prerace measurements. No significant biochemical or mechanical differences were found between runners in terms of their finish times. These findings showed that completing a marathon in hot and humid conditions induced a significant reduction in lower-limb muscle stiffness, body mass, and Mg, and increased neuromuscular fatigue, CPK, and HCT, because of muscle damage and dehydration. Knowledge of the effects of heat and humidity may be of value for coaches and sports medicine practitioners in developing effective hydration and recovery protocols for marathon runners in these special conditions.

Soccer is a very popular sport, which has been widely investigated. However, little is known about the effects of congested fixture periods on muscle mechanical responses since access to elite teams during competitive periods is highly restricted. Thus, the goal of this study was to describe the effects of a short-congested fixture period on the neuromechanical parameters related to fatigue and stiffness of elite young soccer players. Nineteen young elite male soccer players (age 17.13 6 0.51 years, body mass 69.00 6 1.22 kg, and height 174.09 6 0.84 cm) participated in the study. The players took part in a preparatory tournament for the FIFA Ò U-17 World Cup, composed of a total of six matches in 1 week. Pre-and post-tensiomyographic changes were assessed by means of the normalized response speed (V rn) and other tensiomyographic markers related to muscle fatigue (i.e. maximum radial muscle displacement (Dm) and velocities of contraction at 10% and 90% (V 10 and V 90) of both legs in two muscles (biceps femoris and rectus femoris). The players presented a possible to likely impairment in Dm, V 10 , and V 90 of both legs and muscles, with the exception of the nondominant biceps femoris. V rn did not vary in any condition, although it presented a slight tendency to decrease. The data demonstrated impairments in the tensiomyographic markers in both legs and muscles, with the exception of the nondominant biceps femoris. A short-congested fixture period in young soccer players leads to a decrease in muscle stiffness due to cumulative fatigue and lack of muscle recovery, this despite the efforts made by the medical staff to counteract the fatigue caused by the games. The use of tensiomyographic markers could be advantageous for rapidly monitoring neuromechanical muscle impairments throughout competitive soccer periods.

La termografía infrarroja como herramienta efectiva para detectar áreas músculares dañadas después de correr una maratónIntroducción. La termografía infrarroja (TI) es un equipo de imagen que capta las radiaciones de calor emitidas por los cuerpos y las recoge en valores de temperatura. En el ámbito deportivo se utiliza para identificar daños en estructuras músculo-esqueléticas a partir de la variación de la temperatura corporal en zonas anatómicas afectadas.Objetivo. Valorar la efectividad de la TI como herramienta para detectar músculos dañados después de correr una maratón.Materiales y métodos. Se evaluaron 17 corredores antes y después de correr una maratón (42.196 km) utilizando un equipo termográfíco.Resultados. Se encontraron diferencias estadísticamente significativas entre la temperatura previa y posterior a correr una maratón. Se presentó una diferencia entre la medición previa y posterior >1°C en el vasto lateral, vasto medial, recto femoral y aductor de la pierna dominante, lo que, basados en parámetros clínicos, representa un daño en estos músculos. Los aumentos de temperatura se mostraron de manera heterogénea entre las zonas anatómicas.Conclusiones. La TI es una herramienta efectiva para detectar zonas musculares dañadas en corredores después de participar en una maratón.Palabras clave: Termografía; Músculos; Carrera; Lesiones (DeCS). | Abstract |Introduction: Infrared thermography (IT) is an imaging technique that detects heat radiation emitted by an object and collects it to convert it into temperature values. In sports, it is used to identify damage to musculoskeletal structures based on the variation of body temperature in affected anatomical areas.Objective: To assess the effectiveness of IT as a tool to detect damaged muscles after running a marathon. Materials and methods:17 runners were assessed before and after running a marathon (42.196 km) using thermographic equipment.Results: Statistically significant temperature differences were found before and after running a marathon. There was a difference between previous and posterior measurement >1°C in the vastus lateralis, vastus medialis, rectus femoris and adductor of the dominant leg, which, based on clinical parameters, indicates damage in these muscles. Increases in temperature were heterogeneous among anatomical areas. Conclusions:IT is an effective tool for detecting damaged muscle areas in runners after participating in a marathon.Keywords: Thermography; Muscles, Running, Injuries (MeSH).

This study aimed to assess anthropometric, physiological, and fitness variables related to health in 158 participants of a swimming program (89 men and 69 women), distributed in three age groups (18-29 years, 30-39 years, 40-48 years). The following protocols were used: 1) bioimpedance analysis to determine the body weight (BW), body mass index (BMI), and body fat percentage (BFP); 2) a measuring tape to measure waist circumference (WC); 3) an automatic sphygmomanometer to obtain systolic (SBP) and diastolic (DBP) blood pressure; 4) a Sit and Reach test was used to evaluate flexibility and the push-up test to evaluate muscular endurance. The results showed that BFP and (BMI) were the variables in which the highest number of people presented unhealthy values, according to international parameters. Significant differences (p<0.05) were found in SBP, DBP, WC, BFP, BMI, and muscle endurance according to sex and age. Significant correlations were found between physiological responses, physical fitness, and body composition. In conclusion, age and sex influence the results of the variables. Results were found that represent metabolic and cardiorespiratory risk factors.