Validation of loaded Change of Direction tests using Robotic Resistance Technology
MetadataVis full innførsel
Change of direction (CoD) is a fundamental part of field and team sports. It consist of an initial acceleration and deceleration into the a turn with a subsequent re-acceleration in another direction. A myriad of tests has been established in order to measure and analyze CoD, however, most of them is quantified by using time as their main outcome measure. Time tells us who was faster, however, it gives us little to no insight into what mechanics, techniques, phases is used by the “better” athlete. Robotic resistance device has been used in other sports such as sprinting and swimming, where it has been possible to quantify the performance in terms of time, velocity, acceleration, force and power. In order for this kind of depth analysis within CoD there needs to be a method to do so, and if there is to be a new method introduced, it needs to meet a validation criteria to prove itself. To date, three dimensional motion capture is the best option, however, there is issues with cost and the fact that there has to be access to a lab. Therefore, the aim of this to was to 1) develop a new protocols for the m505 test (180 degree turn) under loaded conditions using robotic resistance and 2) determine criterion related validity of continuous velocity measurement of an athlete performing m505 test with a robotic resistance device (ROBvel), and compare it to established methods used for measuring center of mass (COMvel and COMPelvis-vel) in three-dimensional motion capture systems. Eight males and three females were recruited to the study. They were all playing at a moderate to elite level in their respective field based ball sport. The subjects were tested in the lab at the Norwegian School of Sports Sciences. A familiarization session with the test took place >48h before testing day. The testing itself took place over one day. The subjects were dotted up with reflective markers and attached via a belt to the robotic resistance device. They were then asked to perform m505 tests, two on each leg, with all three different loads, 3, 6 and 9kg. The main outcome variable was velocity at the given time interval for the test. The ROBvel data was synchronized to the three dimensional motion capture data (CARvel, COMpelvis-vel, COMvel) and compared using cross correlation analysis which showed strong correlations between the robotic resistance device compared to three dimensional motion capture ROB to CAR (r=.99), ROB and COMpelvis (r=.96) and ROB and COM (r=.94). An unpaired t-test was used to determine the differences between the methods, and it showed that there was no significant difference for all three loads. Bland Altman figures show little to no bias between ROB compared to kinematic data. When looking at the results, it is possible to say that this method met the validation criteria for quantitative testing, and therefore it is a valid method to test and analyze CoD performance in field based sports for both males and females. The use of robotic resistance device can give coaches a more portable and cost effective way to train, test and analyze their athletes, in addition, it can give them valuable insight into what their athletes need to work on.
Masteroppgave - Norges idrettshøgskole, 2021