"Change of direction deficit" measurement in Division I American football players
Australian Strength and Conditioning Association
Faculty of Health, Engineering and Science
School of Exercise and Health Sciences/Centre for Exercise and Sports Science Research
Change of direction (COD) ability is an important physical fitness capacity required in conjunction with cognitiveperceptual ability to perform effective and efficient agility manoeuvres in many sports. Although, the physical capacity to change direction is often measured by strength and conditioning professionals, the ability of these common COD tests (presented as time to complete a running task) to truly measure one’s ability to decelerate and subsequently reaccelerate in a new direction is often tangled within one’s ability to perform straight line running. This has been demonstrated with large to very large correlations found between COD tests and straight-line sprint speed in various studies. The reason for continuing to use these common COD tests, such as the T-test, 505 and proagility is often due to existing data to compare athlete performances and ease of data collection. Some researchers have used the velocity of the centre of mass as a true measure of COD ability. Although assessing COD ability by measuring athlete COM out of a COD step provides a direct measure of COD ability, the scope for strength and conditioning professionals to be able to use this type of assessment is small due to time and equipment constraints. A proposed method, termed “change of direction deficit”, to assess COD ability was calculated to assess if this measure could better isolate COD ability independent of one’s straight-line sprint ability.