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Copyright of Revista Brasileira de Prescrição e Fisiologia do Exercício is the property of Instituto Brasileiro de Pesquisa e Ensino em Fisiologia do Exercicio 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.)

Background: The hyperbolic torque-duration curve depicts critical torque (CT) and W prime (W′), with the curve's asymptote representing CT as the boundary between heavy- and severe-intensity domains. W′, the curvature constant, indicates cumulative work beyond CT. This study investigated age-related reductions in W′, CT, and gait speed, and whether W′ and CT predict gait speed independently of muscle torque. Methods: three groups (adults, middle-aged, older) totaling 131 women were studied. W′ and CT were determined using 60 maximal isometric voluntary contractions of knee extensors. The fast gait speed was calculated in walking tests at 10 m, 400 m, and six minutes (6 MWT). Results: gait speed decreased (p < 0.05) with age, as did W′ and CT. Both W′ and CT correlated positively with gait speed at different distances (10 m, 400 m, 6 MWT). Adjusted for maximum muscle torque, only W′ maintained a positive association (p < 0.05) with all gait speed tests (10 m: β = 0.201, SE = 0.086; 400 m: β = 0.262, SE = 0.085; 6 MWT: β = 0.187, SE = 0.086). Conclusions: aging led to declines in W′, CT, and gait speed. W′, not CT, remained a significant predictor of gait speed, indicating its importance for older women's mobility. [ABSTRACT FROM AUTHOR]

Problem statement: Center-of-mass (CoM) analysis of takeoff speeds in jumps preceded by run-ups (such as volleyball spike jumps), using a force platform, requires prior information on CoM speed at touchdown. This, however, can only be evaluated through kinematic methods (KIN). To this end, KINs must be evaluated for accuracy and concurrent validity. An example is a double integration of force (DIF) method for jumps in which the initial CoM speed is zero in countermovement jumps with and without arm swing. Aim: To evaluate the reliability and accuracy of three methods for calculating takeoff velocity and their concurrent validity during vertical jumps. Material and methods: Fifteen female volleyball players performed 10 vertical countermovement jumps (CMJ), and 10 countermovement jumps with arm swing (CMJa). Two methods were used to measure CoM takeoff velocity: (1) numerical DIF and (2) full-body 3D model (KIN). The latter was implemented using two minimalist marker setups between the right anterior and posterior iliac spines (RASI) and (RPSI), respectively. Results: KIN and DIF were more reliable in all jumps (ICC: 0.93-0.96) than minimalistic methods (ICC: 0.87-0.93). The standard error of measurement was lower in KIN and DIF (SEM mean= 1.9) than in minimalistic methods (SEM mean= 3.1). KIN was valid regarding DIF in CMJ, with bias equal to zero, no proportional bias (p=0.514), and narrow limits of agreement (LoA) (0.1 m/s). KIN was also valid in CMJa (bias = 0.01 m/s), with no proportional bias (p=0.244), LoA =0.21 m/s. The minimalist RPSI method was valid only in CMJ (bias= -0.12m/s), with no proportional bias (p=0.27), LoA=0.31 m/s. The RASI method showed a bias difference compared to DIF (p=0.001) and was not valid with either jump types. A large displacement of the pelvis may lead to increased errors using a single marker. Conclusions: All procedures were reliable and accurate, but minimalist marker setups decreased the values. The KIN method using a Plug-in-Gait model was valid in both jumps. Minimalist marker setups with a single marker at RPSI may be applied only in CMJ. Minimalist marker setups with a single marker may also lead to controversial results depending on the pelvis's jump type and marker position. These possibilities should be considered to calculate takeoff and touchdown velocities during volleyball spike jumps. [ABSTRACT FROM AUTHOR]

Copyright of Revista Brasileira de Prescrição e Fisiologia do Exercício is the property of Instituto Brasileiro de Pesquisa e Ensino em Fisiologia do Exercicio 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 Journal of Physical Education (24482455) is the property of Universidade Estadual de Maringa 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.)

The current investigation aimed to find the difference between right and left lower limb strength of quadriceps and hamstring muscles and describe young futsal players' explosive strength and anaerobic power. The study comprised 12 university male U-20 futsal players (74.5 ± 9.7 kg;173.2 ± 7.2 cm; 18.7 ± 1.2 yrs.). Isometric strength was measured using an isometric dynamometer, lower limb explosive strength was assessed through the Countermovement Jump and anaerobic power was estimated with the Wingate test. Initially, results were displayed through descriptive statistics. Magnitude-based inference with respective Confidence Intervals (CI=90%) and effect size were used to compare inter-lower limb strength. No substantial differences were found between right and left lower limb, to knee extension and flexion. Team's explosive strength and anaerobic power were 36.7 ± 7 cm and 998.3 ± 125.9 W, respectively. These findings suggest that young futsal players' performance may be less affected due to inter-lower limb asymmetries. [ABSTRACT FROM AUTHOR]