Purpose: Recent studies have shown that soccer players’ responses are similar on natural grass (NG) and artificial turf (AT), but they did not control the mechanical properties of these surfaces. This work aimed to analyze the influence of the game surface on amateur soccer players’ physical and physiological responses using a soccer simulation protocol. Methods: A total of 16 amateur players performed 3 bouts of the soccer simulation protocol on AT, and, on another day, 3 bouts on NG. The mechanical properties of both surfaces were recorded. The order of surfaces was randomly established for each participant. Physiological responses of players were assessed before and after the 6-repeated-sprints test existing at the midpoint of each bout. Fatigue (% best; % diff) and general variables (total time; best time, mean time; maximum speed) for both the repeated sprint test (RST) and the agility tests (nonlinear actions at maximum speed) incorporated into the soccer simulation protocol were also analyzed. Results: The 2 surfaces displayed different mechanical properties. Physical responses were found similar for both surfaces (P > .05) before and after the RST. There were no surface differences in sprint times or fatigue variables for the RST (P > .05). The agility test was faster on AT than on NG in bout 1 (average speed [+1.17 km/h;P = .037]; agility test cut time [−0.31 s; P = .027] and best time [−0.52 s; P = .042]). Conclusions: The differences in the mechanical properties of the 2 surfaces are not sufficient to cause differences in the physiological and physical responses of soccer players, although they may affect turns and cuts.
Jorge López-Fernández, Javier Sánchez-Sánchez, Jorge García-Unanue, José Luis Felipe, Enrique Colino and Leonor Gallardo
Luis Suarez-Arrones, Javier Núñez, Eduardo Sáez de Villareal, Javier Gálvez, Gabriel Suarez-Sanchez and Diego Munguía-Izquierdo
To describe the repeated-high-intensity activity and internal training load of rugby sevens players during international matches and to compare the differences between the 1st and 2nd halves.
Twelve international-level male rugby sevens players were monitored during international competitive matches (n = 30 match files) using global positioning system technology and heart-rate monitoring.
The relative total distance covered by the players throughout the match was 112.1 ± 8.4 m/min. As a percentage of total distance, 35.0% (39.2 ± 9.0 m/min) was covered at medium speed and 17.1% (19.2 ± 6.8 m/min) at high speed. A substantial decrease in the distance covered at >14.0 km/h and >18.0 km/h, the number of accelerations of >2.78 m/s and >4.0 m/s, repeated-sprint sequences interspersed with ≤60 s rest, and repeated-acceleration sequences interspersed with ≤30 s or ≤60 s rest was observed in the 2nd half compared with the 1st half. A substantial increase in the mean heart rate (HR), HRmax, percentage of time at >80% HRmax and at >90% HRmax, and Edwards training load was observed in the 2nd half compared with the 1st half.
This study provides evidence of a pronounced reduction in high-intensity and repeated-highintensity activities and increases in internal training load in rugby sevens players during the 2nd half of international matches.
Pedro L. Valenzuela, Guillermo Sánchez-Martínez, Elaia Torrontegi, Javier Vázquez-Carrión, Manuela González, Zigor Montalvo and Grégoire P. Millet
Purpose: Repeated-sprint training (RS) is commonly conducted in normoxia, but its completion with localized (blood-flow restriction [BFR]) or systemic hypoxia has been proven effective for performance enhancement. Yet, few studies have applied these types of RS sessions in racket sports. The authors aimed to determine the acute responses to these types of training in elite badminton players. Methods: Eight male elite badminton players participated in this randomized crossover study. They performed 3 on-court RS sessions, each consisting of 3 sets of 10 repetitions of 10-s badminton-specific movements in normoxia (RSN), systemic normobaric hypoxia (RSH, FiO2 = 14%), or with BFR (RS-BFR, 40% arterial occlusion pressure). Performance, perceptual (ie, rating of perceived exertion), and physiological (ie, pulse saturation, muscle oxygenation, blood lactate, creatine kinase, heart-rate variability) responses were measured after each set and up to 48 h postsession. Results: RS-BFR induced a greater performance impairment (lower distance and accelerations) and a higher local perceived exertion in the legs than RSN and RSH (P < .05), whereas greater overall fatigue was reported with RSH (P < .05). RSH induced a lower saturation (P < .001), but no differences were observed in muscle oxygenation between conditions. No differences in creatine kinase or heart-rate variability were observed at any time point (from baseline up to 48 h after the session). Conclusions: RS-BFR—and, to a lower extent, RSH—resulted in impaired performance and a higher perceived strain than RSN. However, these 2 hypoxic methods do not seem to induce a long-lasting (post 24–48 h) physiological stress in elite badminton players.
Sonsoles Hernández-Sánchez, Pedro L. Valenzuela, Javier S. Morales, Juan J. Carrero, Alejandro Lucia and Jonatan R. Ruiz
Context: Exercise improves the commonly impaired physical fitness and cardiovascular health of transplant recipients. However, concerns remain about the safety of strenuous physical exercise in this population. Purpose: To describe the physiological effects of ultraendurance exercise in a renal transplant recipient. Methods: After a 25-week training program, a 31-year-old male with stage 3 chronic kidney disease who had undergone 2 kidney transplants participated in a 62-km (5600 m of positive altitude change) trail-running race. Blood and urine analyses were performed at baseline (24 h before the race), 4 days after the race, and at different time points up to 16 weeks postexercise. Results: The participant completed the race in 12 hours 18 minutes. No noticeable side effects were recorded during the whole study period, including the prerace training program. No major urine or blood alterations were observed after ultraendurance exercise, with glomerular filtration rate remaining steady during the study period. Conclusions: Ultraendurance exercise induced no adverse physiological effects in a well-trained young renal transplant recipient.
Pedro L. Valenzuela, Carlos Amo, Guillermo Sánchez-Martínez, Elaia Torrontegi, Javier Vázquez-Carrión, Zigor Montalvo, Alejandro Lucia and Pedro de la Villa
Purpose: To determine if transcranial direct-current stimulation (tDCS) could be effective for the enhancement of swimming performance or mood state in elite athletes. Methods : Eight male elite triathletes (age = 20  y, maximal oxygen uptake = 71  mL·kg−1·min−1) participated in this crossover, counterbalanced, sham-controlled, double-blind study. Participants received either actual (20 min of anodal stimulation of the motor cortex at 2 mA) or sham tDCS and performed an 800-m swimming test in which rating of perceived exertion and blood lactate response were measured. Mood state (Brunel Mood Scale) was assessed before and after each tDCS session and after the swimming test. Heart-rate variability and central nervous system readiness were assessed before and after each tDCS session. The chances of finding differences between conditions were determined using magnitude-based inferences. Results : A significant and very likely higher Brunel Mood Scale–determined vigor self-perception was found with actual tDCS after the stimulation session (−0.1 [1.2] and 2.0 [2.3] for sham and actual tDCS, respectively; P = .018, effect size = 1.14) and after exercise (−4.1 [2.9] and −0.9 [3.6] for sham and actual tDCS, respectively; P = .022, effect size = 0.98). However, likely trivial and nonsignificant (P > .05) differences were found between conditions in performance (599  s and 596  s, respectively). Unclear and nonsignificant differences were observed between conditions for the rest of the study end points. Conclusions : tDCS elicited a marked increase in vigor self-perception that was maintained after exercise but failed to improve swimming performance in elite triathletes.