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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. [ABSTRACT FROM AUTHOR]

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 (R² ≈ .96) was observed between the MPV and the percentages of HS 1-RM, resulting in the following equation: %HS 1-RM = -105.05 x 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. [ABSTRACT FROM AUTHOR]

The aims of this study were to describe the session rating of perceived exertion (sRPE), total quality recovery (TQR), and variations in countermovement jump (CMJ) height throughout nine weeks of a competitive period in young female basketball players. In total, 10 young female basketball players (17.2 ± 0.4 years; 71.8 ± 15.0 kg; 177.2 ± 9.5 cm) participated in this study. The sRPE and TQR were assessed in each training session, whereas the CMJ height was assessed prior to the first weekly training session. The magnitude-based inferences method was used to compare the sRPE, TQR, and CMJ height across the nine weeks of training. The training loads accumulated in weeks 1, 2, and 3 were likely to almost certainly be higher than in the following weeks (ES varying from 0.67 to 2.55). The CMJ height in week 1 was very likely to be lower than in weeks 2, 5, 7, and 8 (ES varying from 0.24 to 0.34), while the CMJ height of the 9th week was likely to almost certainly be higher than all previous weeks of training (ES varying from 0.70 to 1.10). Accordingly, it was observed that when higher training loads were accumulated, both CMJ and TQR presented lower values than those presented during periods with lower internal training loads. These results highlight the importance of using a comprehensive and multivariate approach to effectively monitor the physical performance of young athletes. [ABSTRACT FROM AUTHOR]

To describe the heart rate variability ( HRV) of high-level sprinters in both the supine and standing positions, the HRV of 7 male (24 ± 6 years; 80 ± 8 kg and 182 ± 7 cm) and 11 female (27 ± 5 years; 61 ± 4 kg; 167 ± 5 cm) high-level Brazilian sprinters was measured in the standing and supine body positions in both the time and frequency domains. The heart rate ( HR) and the time ( SDNN, RMSSD) and frequency ( LF; HF and LF: HF) domains of the HRV were assessed. Natural log-transformations (ln) of all HRV indices were log-transformed prior to analysis to reduce bias arising from non-uniformity of error. The Cohen's effect size and magnitude-based inference ( MBI) were obtained for comparisons. The results suggest higher cardiac autonomic stress in the standing position than in the supine for both genders. With the exception of the ln SDNN that showed possibly MBI in female athletes, all other HRV indices presented a likely or almost certainly MBI. Male athletes demonstrated a higher ln SDNN in the supine body position ( very likely MBI) and a higher HR in the standing position ( very likely MBI) than females. In conclusion, elite sprinters (independent of the gender) present lower HRV in the standing position than in the supine position, but males present a more notable change in cardiac autonomic stress than female athletes. [ABSTRACT FROM AUTHOR]

This study aimed at testing whether there are mean propulsive velocities (MPVs) capable of maximising the mean propulsive power (MPP) during the execution of bench press (BP), bench throw (BT), half squat (HS) and jump squat (JS). Additionally, we assessed the differences in MPP/MPV between ballistic and traditional exercises. Seventeen male rugby sevens players performed MPP tests in BP, BT, HS and JS and maximum isometric force (MIF) tests in HS and BP. The JS presented higher MPP (977.4 ± 156.2 W) than the HS (897.9 ± 157.7 W) (P < 0.05); the BP (743.4 ± 100.1 W) presented higher MPP than the BT (697.8 ± 70.4 W) (P < 0.05). Ballistic exercises presented higher optimum MPV (JS = 1.02 ± 0.07 m·s−1; BT = 1.67 ± 0.15 m·s−1) than traditional exercises (HS = 0.93 ± 0.08 m·s−1; BP = 1.40 ± 0.13 m·s−1) (P < 0.05). The optimum MPP in the JS, BT, HS and BP occurred at 28.2 ± 5.79, 23.3 ± 4.24, 32.4 ± 9.46 and 27.7 ± 5.33% of the MIF, respectively. The coefficient of variation (CV) of MPV at optimum MPP ranged from 7.4% to 9.7%, while the CV of %MIF ranged from 18.2% to 29.2%. The MPV is a more precise indicator of the optimum loads than the percentages of MIF due to its low inter-subject variability as expressed by CV. Therefore, MPV can be used to determine the optimum power load in the four investigated exercises. [ABSTRACT FROM PUBLISHER]

Copyright of ConScientiae Saúde is the property of Nove de Julho University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of ConScientiae Saúde is the property of Nove de Julho University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Tensiomyography (TMG) has been used as a simple and non-invasive tool to assess the mechanical properties of skeletal muscles. The TMG-derived velocity of contraction (Vc), which can be calculated from the ratio between maximal radial displacement and the sum of contraction time and delay time, has been proposed for evaluating athletes. However, its sensitivity to training effects and possible relation with changes in soccer players' neuromuscular performance have not yet been addressed. To test this possibility, twenty-two male Brazilian elite soccer players were assessed using TMG-derived Vc, unloaded squat jump, countermovement jump and drop jump at 45 cm, loaded jump squat and linear (20 m) and change of direction (COD) sprint tests, prior to and after an 8-week period, between two consecutive official tournaments, during which the concurrency between endurance and strength-power training commonly impairs neuromuscular capacities. Magnitude-based inference was used to detect meaningful training effects. From pre- to post-tests, it was observed likely to almost certainly improvements in all modes of jumping tests. In addition, we could verify decrements in the 20-m and COD sprint performances, which were rated as very likely and almost certainly, respectively. Finally, both rectus femoris and biceps femoris muscles presented a likely reduction in Vc. Therefore, chronic decreases in sprinting speed are possibly accompanied by a reduced TMG-derived Vc. From a practical standpoint, the TMG-derived Vc can be used to monitor negative specific-soccer training effects related to potential impairments in maximum speed. [ABSTRACT FROM AUTHOR]

Background: The purpose of this study was to analyze the effects of four weeks of training cessation (TC) on specific endurance performance, resting and postexercise heart rate variability (HRV) and neuromuscular capacities of high-level endurance runners., Methods: Eighteen endurance runners, 8 men and 10 women (25.5±7.5 years; 166.9±7.6 cm; 54.2±6.9 kg), took part in this study. The 3000 m time trial performance, resting HRV, 5'-5' test, squat and countermovement jumps (SJ and CMJ, respectively) and mean propulsive power in the jump squat exercise relative to body mass (MPP JS REL) were performed pre and immediately following the 4-week TC. The inference based on magnitudes were used to analyze the differences between pre and post values., Results: The time in the 3000 m time-trial was almost certainly higher after TC. A very likely decrease was noticed in the resting HRV Index after the TC period. The differences in all variables analyzed during the 5'-5' test were rated as unclear. No differences were observed in SJ and CMJ comparing the pre and post moments of TC, while the MPP JS REL was very likely improved after the TC period., Conclusions: The resting HRV accompanied the reductions in the specific endurance performance while the 5'-5' test variables did not. The lack of training stimulus led to improvement in the MPP JS REL, possibly due to the withdrawal of specific endurance training, which strongly concurs with neuromuscular performance.

Background: The aim of this study was to compare performance in the Yo-Yo IR1, 20-meter sprint, COD test, loaded and unloaded lower-limb muscle power tests (squat jump [SJ], countermovement jump [CMJ] and jump squat [JS] tests), as well as resting and exercise heart rate variability parameters in high-level senior professional and under-20 (U-20) futsal players., Methods: All the players (18 senior and 15 U-20 male players) performed the Yo-Yo Intermittent Recovery Test level 1 (Yo-Yo IR1), 20-m sprint, COD test, loaded and unloaded lower-limb power tests (SJ, CMJ and JS tests), as well as resting and post-exercise log-transformed root-mean-square difference of successive normal RR intervals (lnRMSSD) recording. The t-test for independent samples and magnitude-based inference were used to compare the groups., Results: Seniors were likely to very likely superior than U-20 in the Yo-Yo IR1 (1506.7±287.1 and 1264.0±397.9 m, P<0.05), and resting (3.43±0.32 and 3.21±0.37 ms) and post-exercise lnRMSSD (2.95±0.39 and 2.48±0.59 ms, P<0.05). Conversely, U-20 players performed very likely to almost certainly better than seniors in the relative mean propulsive power (10.39±1.60 and 9.05±1.57 W/kg, P<0.05), 20-m sprint time (2.92±0.10 and 3.05±0.10 s, P<0.05) and COD (5.50±0.15 and 5.71±0.22 s, P<0.05)., Conclusions: Findings from this cross-sectional study indicate that long-term exposure to futsal may lead to improvement in the aerobic fitness and cardiac autonomic regulation, while impairing the muscle power and speed performance of players. Future longitudinal studies are necessary to confirm the occurrence of such concurrent training adaptations.

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 (R2 ≈ .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.