Effects of continuous and intermittent endurance exercise in autonomic balance, rating perceived exertion and blood lactate levels in healthy subjects

Purpose The aim of this study was to determinate the changes in the Autonomic Balance, Rating Perceived Exertion (RPE) and blood lactate after continuous versus intermittent exercise protocols. Methods En el estudio participaron 7 varones activos y sanos (33 ± 5,1 años). Cada sujeto realizó 2 protocolos de ejercicios: a) un ejercicio continuo al 110% del umbral del lactato (CONT); el protocolo CONT consistió en una carrera continua, siendo la distancia cubierta en metros igual a la distancia de la sesión intermitente, y b) un ejercicio intermitente al 100% de la velocidad pico en cinta (INTT). El protocolo consistió en 30 min de carrera de 15 segundos, intercalados con 15 segundos de descanso pasivo. El balance autónomo se evaluó mediante el ratio LF/HF antes de comenzar los ejercicios, inmediatamente después de finalizar los mismos, y a las 24 h de su finalización; la RPE se evaluó cada 5 min en cada protocolo de ejercicios, y el lactato en sangre se midió inmediatamente tras ambos protocolos. El nivel alfa se estableció en p ≤ 0,05. Seven active and healthy male (33 ± 5.1 years) participated in the study. Each subject performed two exercise protocols: (i) a continuous exercise at 110% of the lactate threshold (CONT). The CONT protocol consisted in continuous running, and the distance covered was the same in meters as it was in the intermittent session, and (ii) an intermittent exercise at 100% of the Peak Treadmill Velocity (INTT). The protocol consisted of 30 min of 15 s running, interspersed with 15 s of passive rest. Autonomic balance was assessed through the LF/HF ratio, before beginning the exercises, immediately finishing the exercises and 24 h post-exercise; RPE was evaluated every 5 min in each exercise protocol; and blood lactate was measured immediately after both protocols. Alpha level was set at P ≤ .05. Results Autonomic balance did not show significant differences between protocols (P = .60). RPE during INTT exercise was significantly higher than CONT exercise (P = .01). Blood lactate levels after exercise did not show significant differences (P = .68). Heart rate variability parameters in the time domain (mean RR and pNN50) show no statistical differences between both protocols pre and 24 h post exercise (P = .24 and P = .61, respectively)

Efecte de l’entrenament de resistència continu i intermitent sobre el balanç autònom, la valoració de l’esforç percebut i els nivells de lactat a la sang en subjectes sans

Objectiu La finalitat d’aquest estudi fou determinar els canvis del balanç autònom, la valoració de l’esforç percebut (VEP) i el lactat sanguini, després d’un protocol d’exercici aeròbic continu i un d’intermitent. Mètodes Participaren a l’estudi 7 homes actius i sans (33 ± 5,1 anys). Cada subjecte féu 2 protocols d’exercicis: a) un entrenament continu al 110% del llindar del lactat (CONT); el protocol CONT consistí en una cursa contínua, essent la distància recorreguda en metres igual a la distància de la sessió intermitent, i b) un entrenament intermitent al 100% de la velocitat pic en cinta (INTT). El protocol consistí en 30 min de cursa de 15 s, intercalats amb 15 s de descans passiu. El balanç autònom s’avaluà mitjançant la ràtio LF/HF abans de començar els exercicis, immediatament després de finalitzar-los, i 24 h després d’haver-los finalitzat; l’VEP s’avaluà cada 5 min en cada protocol d’exercicis, i el lactat a la sang es mesurà immediatament després d’ambdós protocols. El nivell alfa s’establí en p ≤ 0,05. Resultats El balanç autònom no mostrà diferències significatives entre ambdós protocols (p = 0,60). L’VEP durant l’exercici INTT fou considerablement superior a l’exercici CONT (p = 0,01). Els nivells de lactat a la sang no reflectiren diferències significatives (p = 0,68). Els paràmetres de variabilitat de la freqüència cardíaca en el domini del temps (mitjana RR i pNN50) no reflectiren diferències estadístiques entre ambdós protocols, amb mesuraments previs i a les 24 h de l’exercici (p = 0,24 i p = 0,61, respectivament). Conclusions Les dades suggereixen que l’entrenament intermitent es percep més intens que el continu, tot i que ambdós protocols reflectiren càrregues internes similars quant a balanç autònom i nivells de lactat a la sang

Effects of Exercise Training under Hyperbaric Oxygen on Oxidative Stress Markers and Endurance Performance in Young Soccer Players: A Pilot Study

The aim of the present study was to determine the effects of three weeks of hyperbaric oxygen (HBO2) training on oxidative stress markers and endurance performance in young soccer players. Participants (18.6±1.6 years) were randomized into hyperbaric-hyperoxic (HH) training (n=6) and normobaric normoxic (NN) training (n=6) groups. Immediately before and after the 5th, 10th, and 15th training sessions, plasma oxidative stress markers (lipid hydroperoxides and uric acid), plasma antioxidant capacity (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid [TROLOX]), arterial blood gases, acid-base balance, bases excess (BE), and blood lactate analyses were performed. Before and after intervention, maximal oxygen uptake (VO2max) and peak power output (PPO) were determined. Neither HH nor NN experienced significant changes on oxidative stress markers or antioxidant capacity during intervention. VO2max and PPO were improved (moderate effect size) after HH training. The results suggest that HBO2 endurance training does not increase oxidative stress markers and improves endurance performance in young soccer players. Our findings warrant future investigation to corroborate that HBO2 endurance training could be a potential training approach for highly competitive young soccer players

Mechanical determinants of sprinting and change of direction in elite female field hockey players

Profile determination in field hockey is critical to determining athletes’ physical strengths and weaknesses, and is key in planning, programming, and monitoring training. This study pursued two primary objectives: (i) to provide descriptive data on sprinting, deceleration, and change of direction (COD) abilities and (ii) to elucidate the mechanical variables that influence sprint and COD performance in elite female field hockey players. Using radar and time-gate technology, we assessed performance and mechanical data from 30 m sprinting, deceleration, and COD tests for 26 elite female hockey players. A machine learning approach identified mechanical variables related to sprint and COD performance. Our findings offer a framework for athlete categorization and the design of performance-enhancing training strategies at the international level. Two pivotal mechanical variables—relative maximum horizontal force (F0) and maximum velocity (Vmax)—predominantly influence the times across all tested distances. However, the force–velocity profile (FVP) and horizontal deceleration do not influence the variance in the COD test outcomes. These insights can guide the design, adjustment, and monitoring of training programs, assisting coaches in decision making to optimize performance and mitigate injury risks for female hockey players

ISOKINETIC STRENGTH IN FEMALE SOCCER PLAYERS BY PLAYER POSITION

This study aimed to establish reference values and compare isokinetic performance in female soccer players according to player position. Eighty-seven female soccer players from the Chilean first-division soccer clubs were evaluated in isokinetic strength. The player position was grouped as goalkeeper (GK), central defender (CD), lateral defender (LD), midfielder (MF), and forward (FW). Concentric knee extension and flexion muscle strength measurements were conducted using a standardized test protocol with an angular velocity of 60º/sec. There were no differences in peak torque of knee extension and flexion between player positions in both the dominant leg (DL) and the nondominant leg (NDL). The H:Q ratio shows significant differences (p=0.0379) in the dominant leg between CD vs. MF (GK: 63.1±11.1; CD: 55.6±4.6; LD: 62.5±9.6; MF: 64.8±12.0; FW: 61.1±10.9). Our results can be used for practitioners working with female professional soccer players to assess and monitor strength according to player position to improve performance. Future studies should confirm whether these values can be used as risk factors, complementing other functional metrics (e.g., eccentric force) and different angular velocities

CORRELATION BETWEEN JUMP HEIGHT AND BIOMECHANICAL VARIABLES IN CHILEAN ATHLETES OF TEAM SPORTS

I In elite team sports technical skills and explosiveness are essential to get the optimum performance, being the vertical jump one of the most important motor skills in competition, usually assessed by countermovement jump (CMJ). The main aim of our study is to determine the correlation between jump height and kinetic and kinematic variables using force platforms, and secondly to describe CMJ values of elite Chilean team sports athletes. The results obtained in our study showed a positive correlation between jump height and concentric mean power, concentric peak velocity, concentric peak power and total concentric impulse. These results are fundamental for an optimal analysis of athletes jumping tests, based on data from the specific study population and the use of those variables that are most related to their performance

Training at moderate altitude improves submaximal but not maximal performance-related parameters in elite rowers

Maximal oxygen consumption (V̇O2max), physiological thresholds, and hemoglobin mass are strong predictors of endurance performance. High values of V̇O2max, maximal aerobic power (MAP), and power output at anaerobic thresholds are key variables in elite rowers. Endurance athletes often use altitude training as a strategy to improve performance. However, no clear evidence exists that training at natural altitude enhances sea-level performance in elite rowers. This study aimed to evaluate the effect of altitude training on rowing-performance parameters at sea level. The study was conducted on eleven rowers (Six females, five males) from the Chilean National Team during a 3-week moderate altitude training (∼2,900 m. a.s.l.) under the live high-train high (LHTH) model. It included a rowing ergometer maximal incremental test and blood analysis (pre and post-altitude). Gas exchange analysis was performed to measure V̇O2max, ventilatory thresholds (VTs) and rowing economy/efficiency (ECR/GE%). LHTL training improves performance-related variables at sea level (V̇Emax: 3.3% (95% CI, 1.2–5.5); hemoglobin concentration ([Hb]): 4.3% (95% CI, 1.7–6.9); hematocrit (%): 4.5% (95% CI, 0.9–8.2); RBC (red blood cells) count: 5.3% (95% CI, 2.3–8.2); power at VT2: 6.9% (95% CI, 1.7–12.1), V̇EVT2: 6.4% (95% CI, 0.4–12.4); power at VT1: 7.3% (95% CI, 1.3–13.3), V̇EVT1: 8.7% (95% CI, 1.6–15.8)) and economy/efficiency-related variables (ECRVT2: 5.3% (95% CI, −0.6 to −10.0); GE(%): 5.8% (95% CI, 0.8–10.7)). The LHTH training decreased breathing economy at MAP (−2.8% (95% CI, 0.1–5.6)), pVT2 (−9.3% (95% CI, −5.9 to −12.7)), and pVT1 (−9.3% (95% CI, −4.1 to −14.4)). Non-significant changes were found for V̇O2max and MAP. This study describes the effects of a 3-week moderate altitude (LHTH training) on performance and economy/efficiency-related variables in elite rowers, suggesting that it is an excellent option to induce positive adaptations related to endurance performance

PHYSICAL AND BIOMECHANICAL ASPECTS THAT CAN INFLUENCE THE PREFERENCE FOR THE UCHIMATA TECHNIQUE IN JUDO: A CASE STUDY

The aim of this study was to compare the handgrip strength, flexibility level (sit and reach test), kumikata and biomechanical aspects of the uchimata technique of two national level judokas, one who favors to use the uchimata (tokui-waza), and one who selects another judo technique in combat. We recorded the highest value of three attempts for handgrip strength (handgrip test), and flexibility (sit and reach); we recorded the highest value of three attempts for strength (handgrip test) and flexibility (sit and reach test); we analyzed the uchimata phases (kuzushi, tsukuri, kake and zanshi) in 3D using Vicon® system. We found that non-traditional kumikata during combat (grips with both hands on the same side), greater level of flexibility (45 vs. 36 cm), greater leg opening distance (113 vs. 66 cm) and greater displacement speed of the center of mass performing the technique (75 vs. 49 cm/s) may be indicators for the choice of uchimata technique as tokui-waza

INCIDENCES OF STIFFNESS ON SQUAT JUMP VARIABLES

The purpose of this study was to relation level the stiffness of the patellar tendon and three portions of the Achilles tendon; inferior, middle, and superior location with performance variables in the squat jump. The sample was composed of 25 belonging to Chilean elite male handball players. It assesses stiffness tendinous patellar and Achilles tendon using to MyotonPro® device. During the squat jump assessment, two force platforms Pasco and ForceDecks® software for analysis. The main results were RFD 0-50 ms (r=0.611), RFDN 0-50 ms (r=0.550), RFD 0-100 ms (r=0.615), and RFDN 0-100 ms (r=0.624) presented a relationship with patellar stiffness, while that Achilles tendon was down relation with peak power in squat jump (r=472). This information can be useful for training judo athletes. From the results, it can be concluded that the stiffness of the patellar tendon and the Achilles tendon determine some mechanical variables of the SJ, mainly in relation to the RFD