No description available.

Abstract available in the Medicine and Sciences in Sports and Exercise.

Eight male collegiate weightlifters (age: 21.2 ± 0.9 years; height: 177.6 ± 2.3 cm; and body mass: 85.1 ± 3.3 kg) participated in this study to compare isometric to dynamic force-time dependent variables. Subjects performed the isometric and dynamic mid-thigh clean pulls at 30–120% of their one repetition maximum (1RM) power clean (118.4 ± 5.5 kg) on a 61 X 121.9–cm AMTI forceplate. Variables such as peak force (PF) and peak rate of force development (PRFD) were calculated and were compared between isometric and dynamic conditions. The relationships between force-time dependent variables and vertical jump performances also were examined. The data indicate that the isometric PF had no significant correlations with the dynamic PF against light loads. On the one hand, there was a general trend toward stronger relationships between the isometric and dynamic PF as the external load increased for dynamic muscle actions. On the other hand, the isometric and dynamic PRFD had no significant correlations regardless of the external load used for dynamic testing. In addition, the isometric PF and dynamic PRFD were shown to be strongly correlated with vertical jump performances, whereas the isometric PRFD and dynamic PF had no significant correlations with vertical jump performances. In conclusion, it appears that the isometric and dynamic measures of force-time curve characteristics represent relatively specific qualities, especially when dynamic testing involves small external loads. Additionally, the results suggest that athletes who possess greater isometric maximum strength and dynamic explosive strength tend to be able to jump higher. Eight male collegiate weightlifters (age: 21.2 ± 0.9 years; height: 177.6 ± 2.3 cm; and body mass: 85.1 ± 3.3 kg) participated in this study to compare isometric to dynamic force-time dependent variables. Subjects performed the isometric and dynamic mid-thigh clean pulls at 30–120% of their one repetition maximum (1RM) power clean (118.4 ± 5.5 kg) on a 61 X 121.9–cm AMTI forceplate. Variables such as peak force (PF) and peak rate of force development (PRFD) were calculated and were compared between isometric and dynamic conditions. The relationships between force-time dependent variables and vertical jump performances also were examined. The data indicate that the isometric PF had no significant correlations with the dynamic PF against light loads. On the one hand, there was a general trend toward stronger relationships between the isometric and dynamic PF as the external load increased for dynamic muscle actions. On the other hand, the isometric and dynamic PRFD had no significant correlations regardless of the external load used for dynamic testing. In addition, the isometric PF and dynamic PRFD were shown to be strongly correlated with vertical jump performances, whereas the isometric PRFD and dynamic PF had no significant correlations with vertical jump performances. In conclusion, it appears that the isometric and dynamic measures of force-time curve characteristics represent relatively specific qualities, especially when dynamic testing involves small external loads. Additionally, the results suggest that athletes who possess greater isometric maximum strength and dynamic explosive strength tend to be able to jump higher.

Athlete Training Should Proceed From Thorough and Systematic Periodized Plans for the Implementation of Training Loads. The Time-course of Training Should Include Periods of High Loads Punctuated by Reduced Loads and Rest. As There Are a Wide Variety of Means and Methods Used for the Implementation of Loads, There Are Numerous Means and Methods for Enhancing Recovery and Adaptation (Ra). Ra From Athlete Training Are Poorly Understood and in Need of a Model or Framework to Advance Our Ability to Systematically Complement Training With Appropriate Modalities.

Abstract available in the Journal of Strength and Conditioning Research.

No description available.

No description available.

No description available.

Algometers are devices that can be used to identify the pressure and/or force eliciting a pressure-pain threshold. It has been noted in pressure-pain threshold studies that the rate at which manual force is applied should be consistent to provide the greatest reliability. This study tested the reliability and construct validity of an algometer (1000-Hz sampling rate) by manually applying pressure on a force plate (500-Hz sampling rate): 10 sets of 5 applications to 80 N and 1 set of 5 applications to each force level: 20, 30, 40, 50, 60, 70, 80, 90, 100, and 110 N. The investigator had previously become familiar with and practiced with the algometer. The handheld algometer had a 1-cm2 round rubber application surface, and the maximum force reading was compared with maximum force readings by the force plate using SEM and t-tests. Force-time curves were analyzed for average slope representing rate of force application. Average Pearson (r) correlations between the maximum force reading of the algometer and force plate were excellent in both trials to 80 N (r = 0.990) and the incremental trials (r = 0.999). The application of force was reasonably constant, with slopes averaging 6.8 ± 0.932 N·s−1. The SEE was 0.323 N. In conclusion, with previous familiarization and practice, an investigator may have high reliability in the rate of force application. The device itself was also highly correlated with readings from a force plate and, therefore, may be considered valid.

Tumbling take-offs on floor exercise apparatuses of varying stiffness properties may contribute to apparatus behaviors that lead to increased injury exposure. The purpose of this pilot study was to compare the kinematics, kinetics, and timing performance characteristics of a springfloor and a spring-floor with an added Air FloorTM. Five male international gymnasts performed a forward handspring to forward somersault and a round off, flic flac, backward somersault on a standard spring-floor and a spring-floor with an Air FloorTM. Performances were measured via high-speed video kinematics (lower extremity joint angles and positions), electromyography of eight lower extremity muscles, mean peak forces on the feet, and timing. Comparisons of spring-floor types, lower extremity joint angles, lower extremity muscle activations, foot forces, and selected durations were determined. The spring floor with Air FloorTM resulted in longer take-off contact durations than spring-floor alone. Dynamic knee angles may indicate an unexpected and potentially injurious motion of the triceps surae musculotendinous structures. This pilot and hypothesis generating study has suggested future research examining dynamic knee position and angle changes, the role of spring-floor vibration and stiffness in take-offs, and take-off muscle activation alignment with the stiffness of the spring-floor. Pragmatically, there appears to be a convergence of evidence indicating that a slower frequency response of the spring floor may assist tumbling performance and reduce stress and strain in the lower extremity.