Impact of sport specific and generic visual stimulus on a reactive agility test while carrying a rugby ball
Meir, RA, Holding, R, Hetherington, J & Rolfe, M 2013, 'Impact of sport specific and generic visual stimulus on a reactive agility test while carrying a rugby ball', Journal of Australian Strength and Conditioning, vol. 21, sup. 1, pp. 45-49.
One of the essential physical skills attributed to a successful rugby league player is agility (5). Verstegen and Marcello (15) have suggested that agility is a quality that supports the ability to react to a stimulus, start quickly and efficiently, move in the correct direction, and be ready to change direction or stop quickly to make a play in a fast, smooth, efficient, and repeatable manner. Sheppard and Young (12) suggest that a more comprehensive definition of agility should include the physical demands (strength and conditioning), cognitive processes (motor learning) and technical skills (biomechanics) involved in these types of movements. They also propose that agility be defined as: a rapid whole body movement with change of velocity or direction in response to a stimulus. Sheppard and Young (12) identify two broad types of agility. These are: i) reactive agility, that includes physical and cognitive component that requires the athlete to react to some form of visual and or aural stimulus, and ii) change-of-direction speed (CODS), where the athlete negotiates a pre-planned movement requiring them to accelerate and decelerate while also changing direction. Reactive agility (RA) is the term used to distinguish between the traditional definition of agility and a more contemporary definition. With respect to rugby league some researchers have already attempted to develop a RA test specific to this sport (4, 5, 11). However, each of these differs slightly in some way with no gold standard method yet accepted within the literature. Further, one variable that is often neglected is the carrying of a ball. This may have an effect on such factors as acceleration, speed and agility performance due to arm movement restriction, resulting in less balance and reduced ground contact force (10). Previously, studies have been conducted in order to see if there is a quantifiable difference between 30 metre linear sprint times while in possession of a rugby ball and without (6, 17). In both these studies a slightly different research methodology was used but both still reported significantly slower times (P < 0.05) between linear speed running with a ball and without. Importantly, these studies did not consider the effect of a two-handed ball carry on COD speed and RA times. Findings that suggest linear speed is slowed by the two-handed ball carry cannot be assumed to crossover to change-of-direction speed, as previous literature has shown the weak relationship between linear speed and COD performance (3). Another consideration when testing RA is the athlete’s ability to locate a target in a cluttered scene (visual search) or when looking for something when they are not sure where it is (14, 19). Clearly the ability to detect a visual stimulus early might be considered an important factor in superior sporting performance. Numerous studies have been completed in order to compare the differences between high level and low level performers in relation to their visual search qualities. Afonso et al. (2) studied visual search qualities of high-skilled and skilled volleyball players and found that the high-skilled players made a larger number of fixations of shorter duration to several locations in comparison to the skilled playing group. Similar results have been observed in cricket (7) and soccer (9). ‘Advance cue utilisation’ refers to a player’s ability to make accurate predictions based on information arising from an opponent’s posture and bodily orientation (18). The ability to anticipate an opponent’s actions based upon partial or advance sources of information is essential because of the time constraints placed on the performer, particularly in fast ball sports (1). One can assume that advance cue utilisation is crucial for rugby league since being able to anticipate an attacker’s movements, based on subtle body postural alterations, gives a defender a much greater chance of successfully getting into position to execute an effective tackle. In light of the above it appears that a closer examination of the impact of ball carriage and type of visual stimulus (i.e. sport specific or generic) on RAT performance is warranted. The aim of this research was to establish if a RA test, using two different forms of visual stimulus while running either without or with a rugby ball (two-handed carry) would negatively impacted upon RAT time (i.e. increased time over a given distance). A secondary aim was is to establish if a modified RAT specific to rugby league offensive play is a reliable test that could be used in this sport.