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Estudio de las respuestas metabólicas y mecánicas ante ejercicios empleados en el entrenamiento de fuerza a intensidad de umbral láctico

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Sandro Silva
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This study examined the effect of caffeine supplementation (CAFF) in a Wingate test (WT), and the behaviour of blood lactate concentrations (BLa) and neuromuscular fatigue (NMF), measured as reduced countermovement jump (CMJ) performance, in response to the WT. In a double-blind crossover study, 16 participants attended the laboratory twice, separated by a 72-hour window. In the sessions, participants first ingested 6 mg·kg-1 of either CAFF or placebo (PLAC), and then performed a WT. BLa was measured before (L-pre), and 0.5 min (L-post-0.5) and 3.5 min (L-post-3.5) after conducting the WT. The CMJ test was conducted before (CMJ pre), after (CMJ post), and 3 min after completing (CMJ post-3) the WT. The results indicated that CAFF enhanced peak power (Wpeak: + 3.22%; p = 0.040), time taken to reach Wpeak (T_Wpeak: -18.76%; p = 0.001) and mean power (Wmean: + 2.7%; p = 0.020). A higher BLa was recorded for CAFF at L-post-0.5 (+ 13.29%; p = 0.009) and L-post-3.5 (+ 10.51%; p = 0.044) compared to PLAC. CAFF improved peak power (PP; + 3.44%; p = 0.003) and mean power (MP; + 4.78%; p = 0.006) at CMJ pre, compared to PLAC, whereas PP and MP were significantly diminished at CMJ post and CMJ post-3 compared to pre (p < 0.001 for all comparisons) under both the CAFF and PLAC conditions. PP and MP were increased at post-3 compared to post (p < 0.001 for all comparisons) for both conditions. In conclusion, CAFF increased WT performance and BLa without affecting NMF measured by CMJ. Thus, CAFF may allow athletes to train with higher workloads and enhance the supercompensation effects after an adequate recovery period.
Raúl Domínguez
added 4 research items
The present study was to compare and correlate two methods for determination of AnT, through the behavior of blood lactate and an indirect test as critical velocity. A progressive testing of 6 x 1000 m in running track was performed in order to determine the AnTV and three tests with the distances of 1500 m, 3000 m, and 5000 m were performed in order to determine the VCrit. For the determination of AnTV, the behavior of blood lactate concentrations was used through two identification methods, IAT and DMAX. Bland-Altman's visual analysis was used to verify agreement and Pearson's test was used to identify the correlation. It was possible to identify positive correlations between the invasive and non-invasive methods used in the study, and the same was identified in the Bland-Altman's visual analysis. The study found that the anaerobic threshold velocities in the methods that used blood lactate with the indirect methods (Vcrit) are concordant among them, so the presented methods are safe for the training prescription considering the running speed in the anaerobic threshold (AnT) in runners moderately trained.
Purpose: To identify the anaerobic threshold through the lactate threshold determined by Dmax and rating of perceived exertion (RPE) threshold by Dmax and to evaluate the agreement and correlation between lactate threshold determined by Dmax and RPE threshold by Dmax during an incremental test performed on the treadmill in long-distance runners. Methods: A total of 16 long-distance runners volunteered to participate in the study. Participants performed 2 treadmill incremental tests for the collection of blood lactate concentrations and RPE separated by a 48-hour interval. The incremental test started at 8 km·h-1, increasing by 1.2 km·h-1 every third minute until exhaustion. During each stage of the incremental test, there were pauses of 30 seconds for the collection of blood lactate concentration and RPE. Results: No significant difference was found between methods lactate threshold determined by Dmax and RPE threshold by Dmax methods (P = .664). In addition, a strong correlation (r = .91) and agreement through Bland-Altman plot analysis were found. Conclusions: The study demonstrated that it is possible to predict anaerobic threshold from the OMNI-walk/run scale curve through a single incremental test on the treadmill. However, further studies are needed to evaluate the reproducibility and objectivity of the OMNI-walk/run scale for anaerobic threshold determination.
Aims: To determine lactate threshold (LT) by three different methods (visual inspection, algorithmic adjustment, and Dmax) during an incremental protocol performed in the leg press 45° and to evaluate correlation and agreement among these different methods. Methods: Twenty male long-distance runners participated in this study. Firstly, participants performed the dynamic force tests in one-repetition maximum (1RM). In the next session, completed an incremental protocol consisted of progressive stages of 1 min or 20 repetitions with increments of 10, 20, 25, 30, 35, and 40% 1RM. From 40% 1RM, increments corresponding to 10% 1RM were performed until a load in which the participants could not complete the 20 repetitions. A rest interval of 2 min was observed between each stage for blood collection and adjustment of the workloads for the next stage. Results: Our results showed no significant difference in relative load (% 1RM), good correlations, and high intraclass correlation coefficients (ICC) between algorithmic adjustment and Dmax (p = 0.680, r = 0.92; ICC = 0.959), algorithmic adjustment and visual inspection (p = 0.266, r = 0.91; ICC = 0.948), and Dmax and visual inspection (p = 1.000, r = 0.88; ICC = 0.940). In addition, the Bland-Altman plot and linear regression showed agreement between algorithmic adjustment and Dmax (r² = 0.855), algorithmic adjustment and visual inspection (r² = 0.834), and Dmax and visual inspection (r² = 0.781). Conclusion: The good correlation and high agreement among three methods suggest their applicability to determine LT during an incremental protocol performed in the leg press 45°. However, the best agreement found between mathematical methods suggests better accuracy.
Sandro Silva
added 2 research items
This study investigated whether naproxen has an ergogenic effect on neuromuscular performance. A randomized, double-blind, placebo-controlled, crossover trial was conducted on 11 resistance-trained men who performed one strength-training session after taking 500 mg of naproxen and another session after taking a placebo. Participants performed three sets of the horizontal bench press with a load of 90% of repetition maximum (RM) to concentric failure. Outcome variables included number of repetitions, workload, fatigue index (FI), and delayed onset muscle soreness (DOMS). Results showed a statistically insignificant reduction in the number of repetitions for placebo when compared to naproxen, amounting to a relative difference of 44.89%. DOMS was lower in the naproxen group, but differences between conditions were not statistically significant. A statistically significant treatment effect was found for workload, favoring naproxen treatment. A statistically significant difference was found for FI between the second and third sets compared to the first set, with results favoring naproxen. We concluded that naproxen helps enhance neuromuscular outcomes in an acute high-intensity strength training bout.
Introduction:Tennis is characterized by a large number of competitions and little recovery time between them. Thus, tennis players and coaching staff have become interested in the role that nutrition can play in maximizing sports performance. The scientific literature does not have recent narrative and/or systematic reviews about to nutrition in tennis. The aim of this study is to map, describe and discuss the state of the science of nutrition and dietetic practices for tennis players from a theoretical and contextual point of view, to enable focused future systematic reviews. Material and methods: A narrative review through the Dialnet, Elsevier, Medline, Pubmed and Web of Science databases, through a search strategy based on keywords separated by Boolean connectors. A series of inclusion / exclusion criteria were applied to select those investigations that responded to the aim of the work. Results: Nutritional recommendations on carbohydrate intake depend on the training load, 5-7 g/kg/day g/kg/day for normal training and 7-10 g/kg/day for competitive periods or high training load. The recommended protein intake is 1.8 g/kg/day and 1 g/kg/day of lipids. The supplements that can optimize tennis performance are caffeine, sodium bicarbonate, creatine and -alanine. Beetroot juice can be a possible aid to consider in dietetic-nutritional planning in tennis players. Conclusions: Performance and health of tennis player can be optimized, as well as adequate periodization of nutrients and supplements, meeting to the physiological demands of tennis.
Raúl Domínguez
added a research item
Objective: Identify the anaerobic threshold (AnT) through blood lactate concentrations (LTDmax) and rating of perceived exertion (RPE) by the Dmax method (RPETDmax), and to evaluate the correlation between these methods. Methods: Sixteen male long-distance runners participated in the study. Participants performed a gradual incremental test in leg press 45° exercise collecting blood lactate concentrations and perceived exertion. A student's T-test was performed to compare the intensity of exercise in which the LTDmax and RPETDmax were found, and a Pearson test was applied to verify the correlation and intraclass correlation coefficient (ICC). Results: Did not significant difference between the LTDmax and RPETDmax (p<0.05). In addition, a strong correlation (r=0.73) and high ICC (0.822) were observed between them. Conclusions: For the sample studied it was possible to determine the AnT through the kinetics of RPE.
Raúl Domínguez
added 9 research items
This study was designed to identify the blood lactate threshold (LT2) for the half squat (HS) and to examine cardiorespiratory and metabolic variables during a HS test performed at a work intensity corresponding to the LT2. Twenty-four healthy men completed 3 test sessions. In the first, their one-repetition maxi-mum (1RM) was determined for the HS. In the second session, a resistance HS incremental-load test was performed to determine LT2. Finally, in the third session, subjects performed a constant-load HS exercise at the load corresponding to the LT2 (21 sets of 15 repetitions with 1 min of rest between sets). In this last test, blood samples were collected for lactate determination before the test and 30 s after the end of set (S) 3, S6, S9, S12, S15, S18 and S21. During the test, heart rate (HR) was telemetrically monitored and oxygen consumption (VO2), carbon diox-ide production (VCO2), minute ventilation (VE), respiratory exchange ratio (RER), ventilatory equivalent for O2 (VE·VO2-1) and ventilatory equivalent for CO2 (VE·VCO2-1) were monitored using a breath-by-breath respiratory gas analyzer. The mean LT2 for the participants was 24.8 ± 4.8% 1RM. Blood lactate concentrations showed no significant differences between sets 3 and 21 of exercise (p = 1.000). HR failed to vary between S6 and S21 (p > 1.000). The respiratory variables VO2, VCO2, and VE·VCO2-1 stabilized from S3 to the end of the constant-load HS test (p = 0.471, p = 0.136, p = 1.000), while VE and VE·VO2-1 stabilized from S6 to S21. RER did not vary signifi-cantly across exercise sets (p = 0.103). The LT2 was readily identified in the incremental HS test. Cardiorespiratory and metabolic variables remained stable during this resistance exer-cise conducted at an exercise intensity corresponding to the LT2. These responses need to be confirmed for other resistance exercises and adaptations in these responses after a training program also need to be addressed.
Purpose: This study was designed to identify the lactate threshold (LT) and first ventilatory threshold (VT1) in a graded resistance half-squat test and determine whether both thresholds are produced at the same workload. A further goal was to compare the visual inspection and algorithm adjustment methods of detecting both thresholds during graded resistance exercise. Methods: Twenty-four young men completed 2 test sessions 48 h apart; 1) the one-repetition maximum (1RM) was determined, 2) an incremental-load test was performed to locate LT and VT1. VT1 was calculated in three different ways based on pulmonary ventilation, the ventilatory equivalent of oxygen or the end-tidal oxygen pressure (as VT1-VE, VT1-VE·VO2-1, or VT1-PetO2 respectively). Results: LT and VT1 were located at the same intensity of exercise during the incremental load test. Using the algorithm method, the LT and VT1-VE were estimated at 24.8±4.8% 1RM (50.6±10.5 kg) and 23.7±4.8% 1RM (48.4±10.0 kg), respectively; the difference between the two values being non-significant (P=0.127). In addition, positive correlation was observed between the two thresholds (r=0.761; P<0.001; intraclass correlation coefficient (ICC) (0.864). The visual inspection and algorithm adjustment methods provided similar LT and VT1 values (r>0.796; ICC>0.885). Conclusions: The LT and VT1 were readily located during the incremental load half-squat test at similar workloads using both the visual inspection and algorithm adjustment methods. Both thresholds served to define two physiological stages (I, II) corresponding to the zones described for endurance exercise. Thus, both LT and VT1 could be used to prescribe the same intensity of resistance half-squat exercise.
Purpose This study was designed to identify the lactate threshold (LT) and first ventilatory threshold (VT1) in a graded resistance half-squat test and determine whether both thresholds are produced at the same workload. A further goal was to compare the visual inspection and algorithm adjustment methods of detecting both thresholds during graded resistance exercise. Methods Twenty-four young men completed two test sessions 48 h apart; (i) the one-repetition maximum (1RM) was determined, (ii) an incremental load test was performed to locate LT and VT1. VT1 was calculated in three different ways based on pulmonary ventilation, the ventilatory equivalent of oxygen or the end-tidal oxygen pressure (as VT1-VE, VT1-VE·inline image or VT1-PetO2, respectively). Results LT and VT1 were located at the same intensity of exercise during the incremental load test. Using the algorithm method, the LT and VT1-VE were estimated at 24·8 ± 4·8% 1RM (50·6 ± 10·5 kg) and 23·7 ± 4·8% 1RM (48·4 ± 10·0 kg), respectively; the difference between the two values being non-significant (P = 0·127). In addition, positive correlation was observed between the two thresholds (r = 0·761; P<0·001; intraclass correlation coefficient (ICC) (0·864). The visual inspection and algorithm adjustment methods provided similar LT and VT1 values (r > 0·796; ICC > 0·885). Conclusions The LT and VT1 were readily located during the incremental load half-squat test at similar workloads using both the visual inspection and algorithm adjustment methods. Both thresholds served to define two physiological stages (I, II) corresponding to the zones described for endurance exercise. Thus, both LT and VT1 could be used to prescribe the same intensity of resistance half-squat exercise.