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  • Author: Ronaldo Kobal x
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Irineu Loturco, Lucas A. Pereira, Ciro Winckler, Weverton L. Santos, Ronaldo Kobal and Michael McGuigan

Purpose: To examine the relationships between different loading intensities and movement velocities in the bench-press exercise (BP) in Paralympic powerlifters. Methods: A total of 17 national Paralympic powerlifters performed maximum dynamic strength tests to determine their BP 1-repetition maximum (1RM) in a Smith-machine device. A linear position transducer was used to measure movement velocity over a comprehensive range of loads. Linear-regression analysis was performed to establish the relationships between the different bar velocities and the distinct percentages of 1RM. Results: Overall, the correlations between bar velocities and %1RM were strong over the entire range of loads (R 2 .80–.91), but the precision of the predictive equations (expressed as mean differences [%] between actual and predicted 1RM values) were higher at heavier loading intensities (∼20% for loads ≤70% 1RM and ∼5% for loads ≥70% 1RM). In addition, it seems that these very strong athletes (eg, 1RM relative in the BP = 2.22 [0.36] kg·kg−1, for male participants) perform BP 1RM assessments at lower velocities than those previously reported in the literature. Conclusions: The load–velocity relationship was strong and consistent in Paralympic powerlifters, especially at higher loads (≥70% 1RM). Therefore, Paralympic coaches can use the predictive equations and the reference values provided here to determine and monitor the BP loading intensity in national Paralympic powerlifters.

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Irineu Loturco, Timothy Suchomel, Chris Bishop, Ronaldo Kobal, Lucas A. Pereira and Michael McGuigan

Purpose: To compare the associations between optimum power loads and 1-repetition-maximum (1RM) values (assessed in half-squat and jump-squat exercises) and multiple performance measures in elite athletes. Methods: Sixty-one elite athletes (15 Olympians) from 4 different sports (track and field [sprinters and jumpers], rugby sevens, bobsled, and soccer) performed squat and countermovement jumps, half-squat exercise (to assess 1RM), half-squat and jump-squat exercises (to assess bar-power output), and sprint tests (60 m for sprinters and jumpers and 40 m for the other athletes). Pearson product–moment correlation test was used to determine relationships between 1RM and bar-power outputs with vertical jumps and sprint times in both exercises. Results: Overall, both measurements were moderately to near perfectly related to speed performance (r values varying from −.35 to −.69 for correlations between 1RM and sprint times, and from −.36 to −.91 for correlations between bar-power outputs and sprint times; P < .05). However, on average, the magnitude of these correlations was stronger for power-related variables, and only the bar-power outputs were significantly related to vertical jump height. Conclusions: The bar-power outputs were more strongly associated with sprint-speed and power performance than the 1RM measures. Therefore, coaches and researchers can use the bar-power approach for athlete testing and monitoring. Due to the strong correlations presented, it is possible to infer that meaningful variations in bar-power production may also represent substantial changes in actual sport performance.

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Irineu Loturco, Timothy Suchomel, Chris Bishop, Ronaldo Kobal, Lucas A. Pereira and Michael R. McGuigan

Purpose: To identify the bar velocities that optimize power output in the barbell hip thrust exercise. Methods: A total of 40 athletes from 2 sports disciplines (30 track-and-field sprinters and jumpers and 10 rugby union players) participated in this study. Maximum bar-power outputs and their respective bar velocities were assessed in the barbell hip thrust exercise. Athletes were divided, using a median split analysis, into 2 groups according to their bar-power outputs in the barbell hip thrust exercise (“higher” and “lower” power groups). The magnitude-based inferences method was used to analyze the differences between groups in the power and velocity outcomes. To assess the precision of the bar velocities for determining the maximum power values, the coefficient of variation (CV%) was also calculated. Results: Athletes achieved the maximum power outputs at a mean velocity, mean propulsive velocity, and peak velocity of 0.92 (0.04) m·s−1 (CV: 4.1%), 1.02 (0.05) m·s−1 (CV: 4.4%), and 1.72 (0.14) m·s−1 (CV: 8.4%), respectively. No meaningful differences were observed in the optimum bar velocities between higher and lower power groups. Conclusions: Independent of the athletes’ power output and bar-velocity variable, the optimum power loads frequently occur at very close bar velocities.

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Lucas Pereira, Ciro Winckler, Cesar C. Cal Abad, Ronaldo Kobal, Katia Kitamura, Amaury Veríssimo, Fabio Y. Nakamura and Irineu Loturco

This study compared the physical performance of Paralympic sprinters with visual impairments (PSVI) and their guides in jump and sprint tests. Ten PSVI and guides executed squat jumps (SJ), countermovement jumps (CMJ), horizontal quintuple right/left-leg jumps (QR/QL), decuple jumps (DEC), and 50-m-sprint tests. The guides were superior to the PSVI in SJ (35.9 ± 6.3 vs 45.6 ± 3.2 cm), CMJ (38.5 ± 6.2 vs 46.7 ± 4.0 cm), QR (9.2 ± 1.9 vs 12.7 ± 1.0 m), QL (9.4 ± 1.9 vs 13.1 ± 0.8 m), DEC (21.0 ± 3.3 vs. 27.2 ± 1.7 m), and 50-m sprints (8.4 ± 0.4 vs 7.6 ± 0.5 m/s). The average differences between the PSVI and guides in the sprint tests was 10%, range 1–24%. Therefore, substantial differences in sprinting speed (in favor of the guides) between the peers were observed. Coaches should develop strategies to train the guides to improve their muscle-power performance.

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Irineu Loturco, Lucas A. Pereira, Cesar C. Cal Abad, Saulo Gil, Katia Kitamura, Ronaldo Kobal and Fábio Y. Nakamura

Purpose:

To determine whether athletes from different sport disciplines present similar mean propulsive velocity (MPV) in the half-squat (HS) during submaximal and maximal tests, enabling prediction of 1-repetition maximum (1-RM) from MPV at any given submaximal load.

Methods:

Sixty-four male athletes, comprising American football, rugby, and soccer players; sprinters and jumpers; and combat-sport strikers attended 2 testing sessions separated by 2–4 wk. On the first visit, a standardized 1-RM test was performed. On the second, athletes performed HSs on Smith-machine equipment, using relative percentages of 1-RM to determine the respective MPV of submaximal and maximal loads. Linear regression established the relationship between MPV and percentage of 1-RM.

Results:

A very strong linear relationship (R 2 ≈ .96) was observed between the MPV and the percentages of HS 1-RM, resulting in the following equation: %HS 1-RM = −105.05 × MPV + 131.75. The MPV at HS 1-RM was ~0.3 m/s.

Conclusion:

This equation can be used to predict HS 1-RM on a Smith machine with a high degree of accuracy.

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Lucas A. Pereira, Rodrigo Ramirez-Campillo, Saul Martín-Rodríguez, Ronaldo Kobal, César C.C. Abad, Ademir F.S. Arruda, Aristide Guerriero and Irineu Loturco

Purpose: To examine the variations in the velocity of contraction (V c) assessed using tensiomyography, vertical jumping ability, and sprinting speed induced by 4 different exercise protocols (ie, strength, sprint, plyometric, and technical training sessions) in 14 male national-team rugby players (age 21.8 [2.6] y, weight 83.6 [8.5] kg, and height 177.4 [6.7] cm). Methods: Physical tests were conducted immediately before and after 4 distinct workouts in the following order: tensiomyography in the rectus femoris and biceps femoris muscles, squat and countermovement jumps, and 30-m sprint velocity. To analyze the differences in the assessed variables before and after each training session, the differences based on magnitudes were calculated. Results: After strength and plyometric workouts, the players presented possible to almost certain impairments in sprint and jump performance and in the V c of the rectus femoris (effect sizes 0.26–0.64). After the sprint-training session, possible to very likely decreases were observed in the squat jump, 30-m sprint, and V c of the biceps femoris (effect sizes 0.21–0.44). By contrast, after the technical training, athletes demonstrated a possible increase in the squat jump and V c in both muscles examined (effect sizes 0.13–0.20). Conclusions: The main finding of this research is that, for the vast majority of results, the direction of changes observed in V c were the same as those observed in performance assessments. This suggests that V c might be used as a sensitive marker of acute variations in speed and power performance of elite team-sport athletes.