Background and Aims: The accurate mechanisms of ankle instability cannot be assessed in the absence of reliable knowledge about ground reaction force (GRF) variables. The purpose of this study was to evaluate the test-retest reliability of GRF variables during forward and lateral jump-landing in volleyball players with functional ankle instability (FAI). Methods: Eighteen professional volle...

background and objectives: it has been shown that a bout of jumping exercise with weighted vests increases the subsequent countermovement jump height. however, it is not clear whether the improvement in jump height is due to the enhancement of joint power or due to other mechanisms such as neural adaptations. methods: to investigate this dichotomy, we tested the acute neuromechanical changes fo...

Whole-body cryotherapy (WBC) has been used as a recovery strategy following different sports activities. Thus, the aim of the study reported here was to examine the effect of WBC on vertical jump recovery following a high-intensity exercise (HIE) bout. Twelve trained men (mean ± standard deviation age = 23.9±5.9 years) were randomly exposed to two different conditions separated by 7 days: 1) WB...

Patellar tendinopathy is prevalent among athletes, and most likely associated with a high jumping load. If methods for estimating jump frequency were available, this could potentially assist in understanding and preventing this condition. The objective of this study was to explore the possibility of using peak vertical acceleration (PVA) or peak resultant acceleration (PRA) measured by an accel...

The goal of this paper is to investigate jump conditions for unsteady small perturbations at impermeable interfaces, slip or bonded, plane or not, between fluids and structures in the presence of initial flow and prestress. Based on conservative equations obtained from a mixed Eulerian-Lagrangian description, interface conditions are first derived in an elegant and straightforward manner thanks...

the purpose of this study was to profiled the body composition, anthropometric and physical fitness qualities of iranian national adolescent volleyball players, and quantified relationships between these characteristics. the sample of this study was 40 national adolescent volleyball players (age: 17.9±0.3). body composition factors: (weight, bmi, whr, body fat percentage, muscle mass) and anthr...

There is a substantial evidence that plyometric training significantly increases muscular strength and vertical jump. Due to the vigorous nature of this type of training, however, there is a risk of incurring musculoskeletal injuries. Therefore, conducting plyometric exercise programs in an aquatic environment might lead to significant improvements in vertical jump with possibly a lower risk of...

A discrete group G has periodic cohomology over R if there is an element α ∈ Ext RG (R,R) of positive degree and an integer n ≥ 0 such that the cup product map by α induces an isomorphism of Ext RG (R,−) and Ext i+|α| RG (R,−) for i ≥ n. Adem and Smith [1] showed if R = Z, then this condition is equivalent to the existence of a finite dimensional free-G-CW-complex homotopy equivalent to a spher...