Anaerobic Contributions Are Influenced by Active Muscle Mass and The Applied Methodology in Well-Controlled Muscle Group

International Journal of Exercise Science 15(7): 599-615, 2022. The anaerobic metabolism determination is complex and the applied methodologies present limitations. Thus, the purpose of this study was to investigate the effects of different calculations (MAOD vs. AOD) on the anaerobic contribution using the dynamic knee extension. Twenty-four male were recruited [Mean (SD); age 27 (1) years, body mass 90 (3) kg, height 181 (2) cm]. This study was divided into two independent experiments (EXP1: ­one-legged; EXP2: two-legged). In both experiments, it was performed a graded exercise test to determine maximal power (MP-GXT); 2-4 submaximal efforts (VO2-intensity relationship); and an exhaustive effort. The theoretical energy demand for the exhaustive effort (TEDex) was constructed from the submaximal efforts. Therefore, MAOD was assumed as the difference between the TEDex and the accumulated VO2 (AVO2). In contrast, the energy demand for AOD was calculated as the product between VO2 at the end of exercise and time to exhaustion (TEDaod). Thus, AOD was assumed as the difference between TEDaod and AVO2. Bayesian paired t-test was used to compare the differences between the applied methods. Also, correlations between the anaerobic indices and performance were verified. In EXP1, AOD was higher than MAOD [1855 (741) vs. 434 (245); BF10 = 2925; ES = 2.5]. In contrast, in EXP2, MAOD was higher than AOD [2832 (959) vs. 1636 (549); BF10 = 3.33; ES = 1.4]. Also, AOD was correlated to performance (r = .59; BF10 = 4.38). We concluded that MAOD and AOD are a distinct phenomenon and must be utilized according to the exercise model

Correlation between running anaerobic sprint test and anaerobic work capacity in soccer players

Running anaerobic sprint test (RAST) is theoretically an anaerobic measurement. Similarly, anaerobic work capacity (AWC), also evaluates anaerobic performance. However, their relationships as scientifically validated anaerobic tests are still controversial. This study evaluates associations between AWC and maximum velocity (Vmax), mean velocity (Vm) velocity, peak (PP), mean (PMab), absolute (PPab), and relative (PPre) power, fatigue index (IF), and peak lactatemia concentration ([la-]p). Nine sub-17 category soccer players from Ponta Grossa, PR, Brazil were submitted to six 35m efforts separated by 10s intervals to determine PPab, PMab, PPre, PMre, and IF (RAST). After three, five, and seven minutes blood samples were collected to determine [la-]p. Later, exhaustive tests were performed on a treadmill at 100%, 110%, and 120% VO2peak (previously determined). Points obtained in relation to velocity versus 1/tlim were linearly adjusted so that the linear coefficient corresponded to AWC. Possible associations between AWC and the RAST parameters were evaluated by the Pearson correlation test (P\u3c0.05). No significant correlations were seen between AWC and any of the powers, IF, and [la-]p. However, AWC significantly correlated with Vmax (r=0.79) and Vmed (r=0.83). We can therefore conclude that AWC did not correlate with traditional anaerobic parameters determined by RAST, but could predict Vmax and Vmed provided from this test

Determination Of Vo2-intensity Relationship And Maod In Tethered Swimming

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)This study aimed to test the reproducibility of the maximal accumulated oxygen deficit (MAOD) values and VO2-intensity relationship parameters as measured during tethered swimming. 9 swimmers performed an incremental test to determine the maximal aerobic force (MAF), 6 submaximal efforts to develop VO2-intensity relationship, and an exhaustive effort to determine MAOD. The tests were performed twice. The reproducibility of the measurements was tested using intraclass correlation (ICC), typical error (TE) and coefficient of variation (CV). High levels of reproducibility were observed for MAF (TE = 2.6 N; CV = 4.3 %; ICC = 0.98) and VO2-intensity relationship parameters, as intercept (TE = 0.01 L.min(-1); CV = 11.4 %; ICC = 0.97), slope (TE = 0.002 L.min(-1). N-1; CV = 3.1 %; ICC = 0.97) and coefficient of determination (TE = 0.02; CV = 1.8 %; ICC = 0.47). The MAOD values measured during the test (2.9 +/- 1.1 L and 45.3 +/- 14.0 mL. Kg(-1)) and retests (2.9 +/- 1.1 L and 45.2 +/- 12.6 mL. Kg(-1)) were highly correlated (absolute values: ICC = 0.93; relative to body mass values: ICC = 0.89) and presented low values of TE (0.3 L and 4.3 mL. Kg(-1)) and CV (9.5 % for absolute and 9.6 % for relative to body mass values). Thus, we demonstrated the potential use of tethered swimming to assess anaerobic capacity in an aquatic environment.379687693Fundacao de Amparo a pesquisa do Estado de Sao Paulo [2011/05357-9, 2011/16195-0]Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Two different approaches to dry-land training do not improve the water performance of swimmers

International Journal of Exercise Science 16(6): 770-790, 2023. Literature diverges about the performance improvement after dry-land training. Thus, the objective of the present study was to compare the effect of two models of dry-land training. Twenty-nine swimmers were divided into three groups, combined strength and power training (PTG), only strength training (STG), and a control group (CG). Measurements were taken for six weeks, before dry-land exposure (M1), after four weeks of specific training with exposure to dry-land training by two groups (M2), and after two weeks of taper without exposure to dry-land training (M3). Strength in specific exercises, jumping tests, and 50, 100, and 200m freestyle performance were evaluated on M1 and M3, while hematological and strength parameters in tethered swimming were measured in M1, M2, and M3. PTG showed time-effect improvement for 200, 100, and 50m performance (

Glycogen Kinetics of Wistar Rats: Different Exercise Intensities and Tissue Analyzed Influence

International Journal of Exercise Science 15(2): 289-299, 2022. The aim of this study is to verify the influence of the intensity on muscle and hepatic glycogen depletion and recovery kinetics of Wistar rats, submitted to three acute training sessions with equalized loads. 81 male Wistar rats performed an incremental test to determine maximal running speed (MRS) and divided into 4 groups: baseline group (Control; n = 9); low intensity training session (GZ1; n = 24; 48 minutes at 50% of MRS); moderate intensity group (GZ2; n = 24; 32 minutes at 75% of MRS) and high intensity group (GZ3; n = 24; 5x5 minutes and 20 seconds at 90% of MRS). Immediately after the sessions and after 6, 12 and 24 hours, 6 animals from each subgroup were euthanized for glycogen quantification in soleus and EDL muscles and liver. A Two-Way ANOVA and the Fisher\u27s Post-hoc test was used (p \u3c 0.05). Glycogen supercompensation occurred between 6 and 12 hours after exercise in muscle tissue and 24 after exercise in the liver. The muscle and hepatic glycogen depletion and recovery kinetics are not modulated by exercise intensity since the load was equalized, but effects were distinct in different tissues. Hepatic glycogenolysis and muscle glycogen synthesis processes seem to run in parallel

Running aerobic sprint test values compared under different footwear and surface conditions

Running aerobic sprint test (RAST) consists of six 35m maximum sprint efforts with 10s intervals to determine peak (PP), mean (PM), absolute (Pab), and relative (Pre) power and fatigue index (IF). This study compares PPab, PMab, PPre, PMre, IF and peak lactate concentration ([la-]P) under different conditions. Nine category sub-17 football players performed two RAST tests separated by 48h. The first was with trainers on cement (T+Ci) and the second with football boots on grass (C+Gr). Blood samples were taken after the tests to determine [la-]P. PPab, PMab, PPre, PMre, IF, and [la-]P values in both situations. The values were compared by the Student t test for independent samples and possible associations verified by the Pearson correlation test (p\u3c0.05). All parameters were found to be significant different. Significant correlations were observed in PMab (r=0.82), PPre (r=0.63), PMre (r=0.90) and [la-]P (r=0.72), but not between PPabs and IF. We concluded that potentials under C+Gr conditions were inferior to T+Ci, with C+Gr demanding more from the glycolytic pathway

A prototype for dynamic knee extension: construction, force characterization and electromyographic responses

BACKGROUND: In the dynamic knee extension (DKE), a metal bar is positioned parallel to the bicycle frame, replacing the pedal and allowing consecutive extensions instead of a pedaling movement. In this exercise model, the knee joint returns to its initial position passively, allowing studies about the role of anterior thigh muscles during locomotion or balance. However, the DKE ergometer is not commercially available. AIM: To describe the construction, responses, and applicability of a prototype ergometer for DKE. METHOD: In the first experiment, six participants underwent a progressive effort to volitional exhaustion. The electromyography signals of the Vastus Lateralis and Biceps Femoris were monitored. In the second experiment, the twitch interpolation technique was used to test the fatigue status of seven participants after a high-intensity exercise. RESULTS: The force signal has three phases: I: knee extension moment; II: crank draws the metal rod back; III: rapid compression of the load cell by the leg. In addition, Vastus Lateralis activation was higher than Biceps Femorisin all stages (p<0.02). The TI was sensitive to assess the peripheral characteristics of the high-intensity effort. CONCLUSION: The construction of a DKE ergometer is plausible, increasing the possibilities of research into motor behavior

Proposal of a Conditioning Activity Model on Sprint Swimming Performance

This study aimed to propose a conditioning activity (CA) model to stimulate improvement on neuromuscular responses, mechanical parameters and for the 50-m freestyle swimming. Thirteen male swimmers (19 ± 3 years and performances of 77% in relation to World Championship records) performed four CA protocols followed by a maximum performance in the 50-m freestyle. In the first protocol (P1) swimmers performed a standard warm-up (∼15 min); in the second protocol (P2) lunges (3 × 85% of the one-repetition maximum); in the third (P3) pull-ups (3 maximum repetitions) and box jumps 40 cm high and 60 cm deep (1 × 5 with 10% of the corporal weight); and in the fourth protocol (P4) a combination of exercises from the second and third protocols. CA protocols had no effect on the standard warm-up. However, P2 performance (27.01 ± 1.25 s) was similar to P1 (27.01 ± 1.18 s) and presented higher positive effects in mechanical parameters for the swim start performance in comparison to other protocols, contributing to improvements in the 50-m freestyle. In addition, turnaround time also had a negative effect, mainly in P3 (3.12 ± 0.28 s), signaling the improvement of this variable in all protocols (P1: 3.30 ± 0.38 s; P2: 3.17 ± 0.30 s; P4: 3.17 ± 0.34 s). P2 (after: 80 ± 11%; before: 82.7 ± 9.9%) and P3 (after: 82.7 ± 9.9%; before: 85.1 ± 9.7%) presented a possible positive effect on the percentage of voluntary activation in relation to P1 (after: 79.3 ± 10.7%; before: 76.3 ± 12%). In conclusion, the proposed conditioning activity protocols were not efficient for performance improvement in the 50-m freestyle compared to the standard model and seem to specifically influence each phase of the event

As adaptações na capacidade aeróbia não são transferidas para a capacidade de sprints repetitivos

No presente estudo, objetivou-se testar se a melhora da capacidade aeróbia, observada após oito semanas de treinamento, é transferida para a capacidade de sprints repetitivos (CSR). Dez corredores (18 ± 1 ano; estatura de 170,1 ± 8,0 cm; massa corporal de 66,4 ± 6,6 kg) participaram do estudo. A capacidade aeróbia foi considerada como a intensidade correspondente à concentração de 4 mM de lactato (OBLA), determinada durante teste incremental, realizado em pista de atletismo. A capacidade de sprints repetitivos foi avaliada por meio de seis sprints de 35 m, separados por dez segundos de intervalo passivo. Todos os testes foram aplicados antes e após oito semanas de treinamento polarizado. Os efeitos do treinamento foram evidenciados por meio do teste t de Student para amostras dependentes, e as possíveis relações entre as alterações percentuais do OBLA e a CSR foram verificadas pelo teste de correlação de Pearson. Para todas as análises o nível de significância foi de p < 0,05. Após o treinamento, todos os participantes apresentaram aumento significativo da intensidade de OBLA (antes 15,4 ± 0,9 km·h-1; após 17,2 ± 1,6 km·h-1; p = 0,01). Na avaliação da CSR, constatou-se que a velocidade máxima, a velocidade média e o índice de fadiga não foram modificados com o treinamento (p > 0,61). Nenhuma correlação foi observada entre as alterações percentuais da intensidade de OBLA e as alterações das variáveis relacionadas à capacidade de sprints repetitivos (r < – 0,26; p > 0,47). Assim, esses resultados demonstram que a melhora da capacidade aeróbia não é transferida para a CSR, avaliada por meio de seis esforços, separados por dez segundos de intervalo passivo

can a rapid local cooling intervention help young soccer players?

The effects of a cooling strategy following repeated high-intensity running (RHIR) on soccer kicking performance in a hot environment (>30ºC) were investigated in youth soccer players. Fifteen academy under-17 players participated. In Experiment 1, players completed an all-out RHIR protocol (10×30 m, with 30s intervals). In Experiment 2 (cross-over design), participants performed this running protocol under two conditions: (1) following RHIR 5 minutes of cooling where ice packs were applied to the quadriceps/hamstrings, (2) a control condition involving passive resting. Perceptual measures [ratings of perceived exertion (RPE), pain and recovery], thigh temperature and kick-derived video three-dimensional kinematics (lower limb) and performance (ball speed and two-dimensional placement indices) were collected at baseline, post-exercise and intervention. In Experiment 1, RHIR led to small- to-large impairments (p < 0.03;d = −0.42–-1.83) across perceptual, kinematic and performance measures. In experiment 2, RPE (p < 0.01; Kendall’s W = 0.30) and mean radial error (p = 0.057; η2 = 0.234) increased only post-control. Significant small declines in ball speed were also observed post-control (p < 0.05; d = 0.35). Post-intervention foot centre-of-mass velocity was moderately faster in the cooling compared to control condition (p = 0.04; d = 0.60). In youth soccer players, a short cooling period was beneficial in counteracting declines in kicking performance, in particular ball placement, following intense running activity in the heat.9E1A-F9DD-3EB8 | Filipe Manuel ClementeN/