Can kinematic and kinetic differences between planned and unplanned volleyball block jump-landings be associated with injury risk factors?

How reliable are lower limb biomechanical evaluations during volleyball-specific jump-landing tasks?

BACKGROUND

Biomechanical evaluations of sport-specific jump-landing tasks may provide a more ecologically valid interpretation compared to generic jump-landing tasks. For accurate interpretation of longitudinal research, it is essential to understand the reliability of biomechanical parameters of sport-specific jump-landing tasks.

RESEARCH QUESTION

How reliable are hip, knee and ankle joint angles and moment curves during two volleyball-specific jump-landing tasks and is this comparable with the reliability of a generic jump-landing task?

METHODS

Three-dimensional (3D) biomechanical analyses of 27 male volleyball players were performed in two sessions separated by one week. Test-retest reliability was analyzed by calculating integrated as well as 1D intraclass correlation coefficient (ICC) and integrated standard error of measurement (SEM) for hip, knee and ankle angles and moments during a spike and block jump (volleyball-specific tasks), and during a drop vertical jump (generic task).

RESULTS

Reliability of joint angles of volleyball-specific and generic jump-landing tasks are similar with excellent-to-good integrated ICC for hip, knee and ankle flexion/extension (ICC= 0.61-0.89) and hip and knee abduction/adduction (ICC=0.61-0.78) but fair-to-poor ICC for ankle abduction/adduction (ICC=0.28-0.52) and hip, knee and ankle internal/external rotation (ICC=0.29-0.53). Reliability of hip, knee and ankle joint moments was good-to excellent (ICC= 0.62-0.86) except for hip flexion moment during spike jump and drop vertical jump (ICC=0.43-0.47) and knee flexion moment during both volleyball-specific tasks (ICC=0.56-0.57). For all tasks, curve analysis revealed poorer reliability at start and end of the landing phase than during the midpart.

SIGNIFICANCE

Our data suggests that kinematic evaluations of volleyball-specific jump-landing tasks are reliable to use in screening programs, especially in the sagittal plane. Notably, reliability is poorer at the beginning and end of the landing phase, requiring careful interpretation. In conclusion, the results of this study indicate the potential for integration of sport-specific jump-landing tasks in screening programs, which will be more ecologically valid.

A Time-Motion Analysis of the Cross-Over Step Block Technique in Volleyball: Non-Linear and Asymmetric Performances

Blocking performance in volleyball is strongly affected by the time in which the action is executed. This study analyzes the time-motion variables in terms of the player’s role and movement direction (right or left), in different phases of the displacement and jump actions in the cross-over step block technique. A kinematic analysis was conducted with 10 senior male volleyball players. Two series of five repetitions were each recorded and classified in terms of middle-blockers (block in the center and sides of the net) and wing-players (only block in the sides). The results showed that the middle-blockers were significantly slower than the wing-players in the first (0.75 ± 0.24 vs. 0.66 ± 0.19 sec; p = 0.020; ES = −0.37 ± 0.30) and fourth phases (0.33 ± 0.8 vs. 0.29 ± 0.8 sec; p = 0.001; ES = −0.44 ± 0.31), and in the total time for blocking (3.15 ± 0.6 vs. 3 ± 0.58 sec; p = 0.003; ES = −0.23 ± 0.31). Overall, players were significantly faster when moving to the right side, showing performance asymmetries. The fastest phases were also performed just before the jump. These findings provide specific knowledge about the cross-over step block technique in its different phases and displacement direction. This information can be used to improve the movement time in the first defensive action in volleyball.