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  • Author: Pedro L. Valenzuela x
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Pedro L. Valenzuela, Guillermo Sánchez-Martínez, Elaia Torrontegi, Zigor Montalvo, Alejandro Lucia and Pedro de la Villa

Purpose: Enhanced external counterpulsation (EECP) is a recovery strategy whose use has increased in recent years owing to the benefits observed in the clinical setting in some cardiovascular diseases (ie, improvement of cardiovascular function). However, its claimed effectiveness for the enhancement of exercise recovery has not been analyzed in athletes. The aim of this study was to determine the effectiveness of EECP on short-term recovery after a fatiguing exercise bout. Methods: Twelve elite junior triathletes (16 [2] y) participated in this crossover counterbalanced study. After a high-intensity interval training session (6 bouts of 3-min duration at maximal intensity interspersed with 3-min rest periods), participants were assigned to recover during 30 min with EECP (80 mm Hg) or sham (0 mm Hg). Measures of recovery included performance (jump height and mean power during an 8-min time trial), metabolic (blood lactate concentration at several time points), autonomic (heart-rate variability at several time points), and subjective (rating of perceived exertion [RPE] and readiness to compete) outcomes. Results: There were no differences between EECP and sham in mean RPE or power output during the high-intensity interval training session, which elicited a significant performance impairment, vagal withdrawal, and increased blood lactate and RPE in both EECP and sham conditions (all P < .05). No significant differences were found in performance, metabolic, or subjective outcomes between conditions at any time point. A significantly lower high-frequency power (P < .05, effect size = 1.06), a marker of parasympathetic activity, was observed with EECP at the end of the recovery phase. Conclusion: EECP did not enhance short-term recovery after a high-intensity interval training session in healthy, highly trained individuals.

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Pedro L. Valenzuela, Javier S. Morales, Carl Foster, Alejandro Lucia and Pedro de la Villa

Purpose: To analyze the relationship between functional threshold power (FTP) and the lactate threshold (LT). Methods: A total of 20 male cyclists performed an incremental test in which LT was determined. At least 48 h later, they performed a 20-min time trial, and 95% of the mean power output was defined as FTP. Participants were divided into recreational (peak power output < 4.5 W·kg−1; n = 11) or trained cyclists (peak power output > 4.5 W·kg−1; n = 9) according to their fitness status. Results: The FTP (240 [35] W) was overall not significantly different (effect size = 0.20; limits of agreement = −2.4% [11.5%]) from the LT (246 [24] W), and both markers were strongly correlated (r = .95; P < .0001). Accounting for the participants’ fitness status, no significant differences were found between FTP and LT (effect size = 0.22; limits of agreement =2.1% [7.8%]) in trained cyclists, but FTP was significantly lower than the LT (P = .0004, effect size = 0.81; limits of agreement =−6.5% [8.3%]) in recreational cyclists. A significant relationship was found between relative peak power output and the bias between FTP and the LT markers (r = .77; P < .0001). Conclusions: FTP is a valid field test-based marker for the assessment of endurance fitness. However, caution should be taken when using FTP interchangeably with LT, as the bias between markers seems to depend on the athlete’s fitness status. Whereas FTP provides a good estimate of LT in trained cyclists, in recreational cyclists, it may underestimate LT.

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Pedro L. Valenzuela, Javier S. Morales, Adrián Castillo-García and Alejandro Lucia

Purpose: To determine the acute effects of ketone supplementation on exercise performance (primary outcome) and physiological and perceptual responses to exercise (secondary outcomes). Methods: A systematic search was conducted in PubMed, Web of Science, and SPORTDiscus (since inception to July 21, 2019) to find randomized controlled trials assessing the effects of acute ketone supplementation compared with a drink containing no ketones (ie, control intervention). The standardized mean difference (Hedges g) between interventions and 95% confidence interval (CI) were computed using a random-effects model. Results: Thirteen studies met all inclusion criteria. No significant differences were observed between interventions for overall exercise performance (Hedges g = −0.05; 95% CI, −0.30 to 0.20; P = .68). Subanalyses revealed no differences between interventions when analyzing endurance time-trial performance (g = −0.04; 95% CI, −0.35 to 0.28; P = .82) or when assessing the separate effects of supplements containing ketone esters (g = −0.07; 95% CI, −0.38 to 0.24; P = .66) or salts (g = −0.02; 95% CI, −0.45 to 0.41; P = .93). All studies reported increases in plasma ketone concentration after acute ketone supplementation, but no consistent effects were reported on the metabolic (plasma lactate and glucose levels), respiratory (respiratory exchange ratio, oxygen uptake, and ventilatory rate), cardiovascular (heart rate), or perceptual responses to exercise (rating of perceived exertion). Conclusions: The present findings suggest that ketone supplementation exerts no clear influence on exercise performance (from sprints to events lasting up to ∼50 min) or metabolic, respiratory, cardiovascular, or perceptual responses to exercise. More research is needed to elucidate if this strategy could provide ergogenic effects on other exercise types (eg, ultraendurance exercise).

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Jaime Gil-Cabrera, Pedro L. Valenzuela, Lidia B. Alejo, Eduardo Talavera, Almudena Montalvo-Pérez, Alejandro Lucia and David Barranco-Gil

Purpose: To compare the effectiveness of optimum power load training (OPT, training with an individualized load and repetitions that maximize power output) and traditional resistance training (TRT, same number of repetitions and relative load for all individuals) in professional cyclists. Methods: Participants (19 [1] y, peak oxygen uptake 75.5 [6] mL/kg/min) were randomly assigned to 8 weeks (2 sessions per week) of TRT (n = 11) or OPT (n = 9), during which they maintained their usual cycle training schedule. Training loads were continuously registered, and measures of muscle strength/power (1-repetition maximum and maximum mean propulsive power on the squat, hip thrust, and lunge exercises), body composition (assessed by dual-energy X-ray absorptiometry), and endurance performance (assessed on both an incremental test and an 8-min time trial) were collected before and at the end of the intervention. Results: OPT resulted in a lower average intensity (percentage of 1-repetition maximum) during resistance training sessions for all exercises (P < .01), but no differences were found for overall training loads during resistance or cycling sessions (P > .05). Both programs led to significant improvements in all strength/power-related parameters, muscle mass (with no changes in total body mass but a decreased fat mass), and time-trial performance (all Ps < .05). A trend toward increased power output at the respiratory compensation point was also found (P = .056 and .066 for TRT and OPT, respectively). No between-groups differences were noted for any outcome (P > .05). Conclusion: The addition of either TRT or OPT to an endurance training regimen of elite cyclists results in similar improvements of body composition, muscle strength/power, and endurance performance.

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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.

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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.

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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 [2] y, maximal oxygen uptake = 71 [4] 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 [38] s and 596 [39] 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.

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David Barranco-Gil, Jaime Gil-Cabrera, Pedro L. Valenzuela, Lidia B. Alejo, Almudena Montalvo-Pérez, Eduardo Talavera, Susana Moral-González and Alejandro Lucia

Purpose: The functional threshold power (FTP), which demarcates the transition from steady state to non-steady-state oxidative metabolism, is usually determined with a 20-minute cycling time trial that follows a standard ∼45-minute warm-up. This study aimed to determine if the standard warm-up inherent to FTP determination is actually necessary and how its modification or removal affects the relationship between FTP and the respiratory compensation point (RCP). Methods: A total of 15 male cyclists (age 35 [9] y, maximum oxygen uptake 66.4 [6.8] mL·kg−1·min−1) participated in this randomized, crossover study. Participants performed a ramp test for determination of RCP and maximum oxygen uptake. During subsequent visits, they performed a 20-minute time trial preceded by the “standard” warm-up that is typically performed before an FTP test (S-WU), a 10-minute warm-up at the power output (PO) corresponding to 60% of maximum oxygen uptake (60%-WU), or no warm-up (No-WU). FTP was computed as 95% of the mean PO attained during the time trial. Results: Although the FTP was correlated with the RCP independently of the warm-up (r = .89, .93, and .86 for No-WU, 60%-WU, and S-WU, respectively; all Ps < .001), the PO at RCP was higher than the FTP in all cases (bias ± 95% limits of agreement = 57 [24], 60 [23], and 57 [32] W for No-WU, 60%-WU, and S-WU, respectively; all Ps < .001 and effect size > 1.70). Conclusions: The FTP is highly correlated with the RCP but corresponds to a significantly lower PO, being these results independent of the warm-up performed (or even with no warm-up).

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David Barranco-Gil, Lidia B. Alejo, Pedro L. Valenzuela, Jaime Gil-Cabrera, Almudena Montalvo-Pérez, Eduardo Talavera, Susana Moral-González, Vicente J. Clemente-Suárez and Alejandro Lucia

Purpose: To analyze the effects of different warm-up protocols on endurance-cycling performance from an integrative perspective (by assessing perceptual, neuromuscular, physiological, and metabolic variables). Methods: Following a randomized crossover design, 15 male cyclists (35 [9] y; peak oxygen uptake [VO2peak] 66.4 [6.8] mL·kg−1·min−1) performed a 20-minute cycling time trial (TT) preceded by no warm-up, a standard warm-up (10 min at 60% of VO2peak), or a warm-up that was intended to induce potentiation postactivation (PAP warm-up; 5 min at 60% of VO2peak followed by three 10-s all-out sprints). Study outcomes were jumping ability and heart-rate variability (both assessed at baseline and before the TT), TT performance (mean power output), and perceptual (rating of perceived exertion) and physiological (oxygen uptake, muscle oxygenation, heart-rate variability, blood lactate, and thigh skin temperature) responses during and after the TT. Results: Both standard and PAP warm-up (9.7% [4.7%] and 12.9% [6.5%], respectively, P < .001), but not no warm-up (−0.9% [4.8%], P = .074), increased jumping ability and decreased heart-rate variability (−7.9% [14.2%], P = .027; −20.3% [24.7%], P = .006; and −1.7% [10.5%], P = .366). Participants started the TT (minutes 0–3) at a higher power output and oxygen uptake after PAP warm-up compared with the other 2 protocols (P < .05), but no between-conditions differences were found overall for the remainder of outcomes (P > .05). Conclusions: Compared with no warm-up, warming up enhanced jumping performance and sympathetic modulation before the TT, and the inclusion of brief sprints resulted in a higher initial power output during the TT. However, no warm-up benefits were found for overall TT performance or for perceptual or physiological responses during the TT.