Physical Qualities Predict Change-of-Direction Speed but Not Defensive Agility in Australian Rules Football

Abstract

The purpose of this study was to determine the relationships between selected physical qualities, change-of-direction (COD) speed, and defensive agility performance in Australian Rules football players. Twenty-four male community-level players were assessed on sprint acceleration (10-m time), maximum strength (3 repetition-maximum half squat), leg power (countermovement jump), reactive strength (drop jump), and a single COD speed test and a defensive agility test. Change-of-direction speed was correlated with reactive strength (r = -0.645, p = 0.001) and sprint acceleration (r = 0.510, p = 0.011). Multiple regression indicated that the combined physical qualities explained 56.7% of the variance associated with COD speed (adjusted R = 0.567, p ≤ 0.05). Participants were median split into faster and slower COD speed groups, and these were compared by independent t-tests. The faster group was significantly better (p ≤ 0.05) on the sprint acceleration and reactive strength tests (large effect size). The correlations between physical qualities and agility were trivial to small (r = -0.101 to 0.123, p > 0.05) and collectively explained only 14.2% of the variance associated with agility performance (adjusted R = -0.142, p > 0.05). When faster and slower agility groups were compared, there were trivial to moderate differences (p > 0.05) in all physical qualities. It was concluded that reactive strength and sprint acceleration are important for COD speed, but the physical qualities assessed are not associated with defensive agility performance. For agility tasks similar to those in this study, sprint and resistance training should not be emphasized, and training other factors, such as the development of sport-specific technique and cognitive skill, is recommended.

Do stiffness and asymmetries predict change of direction performance?

“…Whilst previous investigations had reported significant correlations (R = -0.44 --0.65) between reactive strength index and CODS performance (Delaney et al, 2015;Young et al, 2002;Young et al, 2015), the current study did not observe this relationship to be significant. Although reactive strength index and leg stiffness may be closely linked, that these terms are not synonymous and should not be used interchangeably.…”

“…Young, James, and Montgomery (2002) Young, Miller, and Talpey (2015) (R = -0.65; P = 0.001) and by Delaney et al (2015) in both dominant (R = -0.44; P < 0.05) and non-dominant limbs (R = -0.45; P < 0.05). Reactive strength is a quality which may be closely linked to stiffness; a stiffer leg-spring should facilitate a more rapid release of elastic energy under circumstances were minimal joint or centre of mass displacement is desired, such as during a drop jump or change of direction (Bret, Rahmani, Dufour, Messonnier, & Lacour, 2002).…”

Relationships between Change of Direction, Sprint, Jump, and Squat Power Performance

“…For this reason, the association between countermovement jump (CMJ) and drop jump (DJ) and COD was extensively studied without producing a clear consensus [6], while relationships with strength or power assessed through closed-kinetic chain exercises have been less examined [2]. While a group of studies show statistical relationships between COD and CMJ [4,6,10,14] and DJ performance [1,6,15], in contrast, others studies have shown lower relationships with no statistical associations with CMJ [8,13] and DJ [4,13,16]. In addition to this, it seems obvious that relative strength/power may be essential for COD performance [17].…”

A Step towards a Field Based Agility Test in Team Sports

“…Agility tasks such as a 1v1 dual [4] allow for greater expression of movement skills in comparison to pre-planned COD tests such as the Y step or 505 (180° COD). Differences in movement patterns and perceptual demands of COD compared to agility tests explain the low shared variance between COD and agility tests [25]. Our findings show the Y step shares 33% of common variance with attacking agility and 5% with defensive agility performance.…”

“…The simulated tackle was detected as a touch on the attacking player and did not involve direct body contact. Objectives and scoring system were explained to participants during the information ses- tests were used to assess the difference between high performing and lower performing agility groups, determined by median splitting the sampled participant's agility score in accordance with previous grouping methods [24,25]. High performers were determined as players with attacking agility ≥ 33%, defensive agility ≥ 67% and composite agility score ≥ 50%, with scores below this forming the lower performing agility group.…”