Journal of Australian Strength and Conditioning Volume 23 | Issue 1 | February 2015 10 Can the 505 change-of-direction speed test be used to monitor leg function following ankle sprains in team sport athletes? J. Aust. Strength Cond. 23(1)10-16. 2015 © ASCA. Original Scientific Research Study CAN THE 505 CHANGE-OF-DIRECTION SPEED TEST BE USED TO MONITOR LEG FUNCTION FOLLOWING ANKLE SPRAINS IN TEAM SPORT ATHLETES? Robert G. Lockie 1 , Samuel J. Callaghan 1 , Matthew D. Jeffriess 1 1 Exercise and Sport Science Department, School of Environmental and Life Sciences, University of Newcastle, Ourimbah, Australia. ABSTRACT Team sport coaches must use tests that can detect functional differences between injured and non-injured legs to monitor athlete recovery. The 505 change-of-direction speed test could be used, as it features sport-specific movements, and isolates cutting off each leg. This study analysed whether the 505, and unilateral vertical (UVJ), standing broad (USBJ), and lateral jump (ULJ) tests, could detect between-leg differences in subjects with a history of ankle sprains. 10 team sport athletes (8 males, 2 females; age = ~23 years; height = ~1.76 m; body mass = ~79 kilograms), with a history of ankle injury in one leg, were recruited. 10 physically matched apparently healthy subjects (8 males, 2 females) were recruited as the comparison control group. Paired samples t-tests (p < 0.05) were used to compare between-leg test performances; effect sizes (ES) were also calculated. Smallest worthwhile change (SWC: 0.20 x standard deviation) calculated smallest worthwhile performance decrement (SWPD; mean ± SWC) from the non-injured leg in the injured group, or the better-performing leg in the healthy group for each test. The UVJ differentiated (p = 0.033; ES = 0.95) between the previously injured and non-injured legs; the USBJ and ULJ did not. The 2% 505 difference when cutting from the injured and non-injured legs was significant (p = 0.007; ES = 0.36). For the UVJ (injured = 33.90 cm; SWPD = 37.98 cm) and 505 (injured = 2.487 s; SWPD = 2.467 s), the injured leg mean was worse than the SWPD, indicating practical value. There were no between-leg differences for the apparently healthy group. Strength and conditioning coaches can use the UVJ and 505 to monitor leg function in their athletes. Key Words - Agility, cutting, unilateral vertical jump, injury monitoring, rehabilitation. INTRODUCTION The ability to change direction while running or sprinting is a fundamental component of most team sports (36). In sports such as soccer (1), basketball (35), and Australian football (7), the ability to change direction can be a defining factor in performance success or failure. Sacco et al. (34) stated that these sport-specific evasive movements, or cuts as they can be termed, involve deceleration about the stance leg, before a reacceleration in a new direction. A high level of force is exerted against the ground during a cut. Indeed, Spiteri et al. (37) found that stronger recreational team sport athletes can produce greater levels of vertical braking, and propulsive force during stance, when compared to weaker athletes. This force production aids in more effective deceleration during the initial stages of the cut, followed by a more efficient reacceleration. An effective cut will also require the stance leg to be suitably positioned, as well as correct sequencing of joint and body movements prior to, and following, the cut (17). If there is any point within the kinetic chain of the legs that is weak or restricted, this can limit the sequencing of appropriate movements (6), particularly during a cut. Ankle sprains are one of the most regular traumas experienced by team sport athletes that can affect this kinetic chain (4, 12, 13), and can lead to compensatory and inefficient movement patterns in an athlete. For example, an athlete with an unstable ankle may compensate by increasing vertical force production during stance in an attempt to decrease eversion forces (8). This will reduce the athlete’s ability to cut through horizontal and lateral planes of movement. Therefore, it is important for team sport and strength and conditioning coaches to be able to monitor their athletes appropriately during rehabilitation from an ankle sprain. In the initial stages of a joint injury, basic range of motion and weight bearing exercises are completed (21). Eventually, however, the athlete needs to be able to complete sport-specific functional tests that can demonstrate that a leg has returned to its normal function following injury. There are a number of factors that must be considered when assessing an athlete’s ability to return to play. This includes ensuring the athlete has the requisite strength and mobility, no compensatory or dysfunctional movements, can make sport-specific movements, and has no pain (16). Limb symmetry has been recommended as a guide for return to sport (16, 39), even though there is no consensus on an acceptable level of symmetry (39). A 10% between-leg disparity in strength and power has been suggested as an indicator of leg dysfunction (38, 39), although this requires further investigation. Nonetheless, assessments that can isolate the relative function of unilateral leg performance are common for injury recovery monitoring. Some field test examples include dynamic stability assessments such as hop-and-holds (31), and more maximal power tests such as unilateral jumps (20). Unilateral jump performance has been used as a functional assessment because they relate to team sport-specific performance (29), and can measure leg strength and power deficits between the legs (18, 20). However, a jump test only provides a singular performance measure of leg