Rugby union is a dynamic running game requiring players to regularly perform change of direction maneuvers to avoid player opposition. The change of direction/cutting task is characterized by rapid deceleration onto the plant leg (PL) then reacceleration by the push-off leg (POL) into the new direction. Identification of the kinematic characteristics of cutting tasks and their relationship to playing ability may offer practical guidelines for coaches and strength and conditioning staff to design effective agility drills and provide player feedback to improve technique. Therefore, the purpose of this study was to investigate the kinematic and temporal characteristics of cutting tasks and their relationship to performance in rugby union players. Semiprofessional rugby union players from the All-Ireland League were placed in a Starters (N = 13) or Nonstarters (N = 10) group based on whether they were routinely selected in the starting team or were reserve 'bench' players. Each participant was fitted with reflective markers and performed 10 cutting trials (5 left, 5 right) of a single 45° cutting task to collect relevant kinematic data. The directions of the cutting trials were classified as a dominant or nondominant cut based on the participant's dominant leg. All trials were then analyzed to determine the timings, angular displacements, and velocities during key events of the PL and POL in the cutting task. The total time to complete the cutting task was not statistically significant between groups; however, Starters demonstrated significantly shorter contact time of the PL during dominant cuts and initiated knee extension of the POL faster than Nonstarters in dominant and nondominant cuts. This preliminary study demonstrates that components of the cutting task differed between groups and may provide an insight for strength and conditioning professionals to assess change of direction technique.
"The ability to change direction is essential for successful performance within multidirectional sports, providing athletes with a mechanism to evade opponents and gain positional advantage during competition (Baker & Newton, 2008; Barnes et al., 2007; Bradshaw, Young, Russell, & Burge, 2011; Green, Blake, & Caulfield, 2011). Several studies have shown significant differences in total change of direction (COD) running time between genders and starters and non-starters (Brughelli, Cronin, Levin, & Chaouachi, 2008; Nimphius, McGuigan, & Newton, 2010), attributing the difference in performance to lower body strength discrepancies (Baker & Newton, 2008; Young, James, & Montgomery, 2002). "
[Show abstract][Hide abstract] ABSTRACT: Abstract Understanding the magnitude of forces and lower body kinematics that occur during a change of direction (COD) task can provide information about the biomechanical demands required to improve performance. To compare the magnitude of force, impulse, lower body kinematics and post-COD stride velocity produced between athletes of different strength levels during a COD task, 12 stronger (8 males, 4 females) and 12 weaker (4 males, 8 females) recreational team sport athletes were recruited. Strength levels were determined by relative peak isometric force of the dominant and non-dominant leg. All athletes performed 10 pre-planned 45° changes of direction (5 left, 5 right) while three-dimensional motion and ground reaction force (GRF) data were collected. Differences in all variables for the dominant leg were examined using a one-way analysis of variance (ANOVA) with a level of significance set at p ≤0.05. The stronger group displayed significantly faster post-COD stride velocity and greater vertical and horizontal braking forces, vertical propulsive force, vertical braking impulse, horizontal propulsive impulse, angle of peak braking force application, hip abduction and knee flexion angle compared to the weaker group. The results suggest that individuals with greater relative lower body strength produced higher magnitude plant foot kinetics and modified lower body positioning while producing faster COD performances. Future investigations should determine if strength training to enable athletes to increase plant foot kinetics while maintaining or adopting a lower body position results in a concomitant increases in post-COD stride velocity.
"It is a complex, contact sport, comprising of bouts of walking, jogging and running, interspersed with sprinting and static exertions (Cahill, Lamb, Worsfold, & Headey, 2013). Changes in direction and center of gravity, incorporating rapid reaction to other players' movements and events are required during play (Green, Blake, & Caulfield, 2011), and must be performed accurately with high velocity to execute game demands at a high level. The maturation of elite junior players to successful senior players is dependent upon the effective development of numerous physical, technical, tactical and psychological attributes required to complete game-related tasks. "
[Show abstract][Hide abstract] ABSTRACT: Objectives
To evaluate performance on selected reach directions of the Start Excursion Balance Test (SEBT) in an elite underage rugby union population, and determine if differences exist between the forward and back position units. This information may have implications for the application of this test in player injury prevention and management.
Gymnasium at an elite junior rugby union screening camp.
102 healthy male elite rugby union players (age = 17.9 ± 1.1 years, height = 1.83 ± 0.07 m, body mass = 90.5 ± 11.3 kg).
Main Outcome Measures
Participants were assessed on the Anterior (A), Posterior-medial (PM), and Posterior-lateral (PL) reach directions of the SEBT.
Normative data for SEBT performance in the A, PM and PL reach directions were established for an elite junior rugby union population. No significant differences in dynamic postural stability were observed between the forward and back position units.
This study provides normative SEBT data on an elite junior rugby union population, which enables clinicians to compare player dynamic postural stability and has implications for use in the prevention and management of player injuries.
Physical Therapy in Sport 01/2013; 15(4). DOI:10.1016/j.ptsp.2013.11.005 · 1.37 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The aim of this study was to compare biomechanical and perceptual-cognitive variables between genders during an offensive and defensive agility protocol. Twelve male and female (n=24) recreational team sport athletes participated in this study, each performing 12 offensive and defensive agility trials (six left, six right) changing direction in response to movements of a human stimulus. Three-dimensional motion, ground reaction force (GRF) and impulse data was recorded across plant phase for dominant leg change of direction (COD) movements, while timing gates and high-speed video captured decision time, total running time and post COD stride velocity. Subjects also performed a unilateral isometric squat to determine lower-body strength, and limb dominance. Group (gender) by condition (2x2) MANOVA's with follow up ANOVA's were conducted to examine differences between groups (p ≤ 0.05). Male athletes demonstrated significantly greater lower body strength, vertical braking force and impulse application, knee and spine flexion, hip abduction, a faster decision time and post COD stride velocity during both agility conditions compared to females. Differences between offensive and defensive movements appear to be attributed to differences in decision time between genders. This study demonstrates that biomechanical and perceptual-cognitive differences exist between genders and within offensive and defensive agility movements.
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