The impact of flexibility on athletic performance is a contentious issue because it seems like every fitness trainee, coach, trainer, therapist, and researcher has a different opinion on the subject. Flexibility's effect on how well one performs in any particular activity depends entirely upon the type of activity, and high levels of flexibility are not always a guarantee of good performance (Sands, 2011).
However, it is obvious even to the most casual observer that flexibility is necessary for success in sports like gymnastics, in which athletes display large ranges of motion with power, speed, and control in ways that would nearly cripple the average gymgoer should they dare attempt such movements. In other sports, like rugby, only a relatively normal level of flexibility is required, and its development is secondary to the improvement of different motor abilities like strength and agility.
Watch several sports for just a short time, and it quickly becomes abundantly clear that the demand for flexibility is specific to each activity. Therefore it should be developed in a way that is specific to each activity (McNeal & Sands, 2006). Keep in mind that flexibility specificity is not limited to the range of motion (or amount of flexibility) required in each sport - the type of flexibility is specific too.
If we go back to the examples mentioned above, dynamic active flexibility is the primary type needed in rugby. In contrast, gymnastics requires dynamic active, static active, and static passive. But even then, the hierarchy in which the athlete should focus on these three types of flexibility will depend upon the specific gymnastics discipline in which they participate.
There is also a need to specify precisely what is meant by the word "performance." For example, does it mean the ability to lift more weight, move at faster speeds, or place the body in a demanding position? It is a difficult question to answer, which is why researchers still cannot provide one after decades of studies. Like injury, performance is multifactorial. Researchers are typically limited to examining relationships between flexibility and intermediate measurable performance factors like speed and strength, a process based on the assumption that these are related to sports performance.
Thus, we can only answer the question in the title of this blog post by asking two further questions: 1) What type of flexibility? And 2) What kind of performance? Only then can we start to properly develop an understanding of the relationship between flexibility and performance.
Sands, W. A. (2011) Flexibility. In: Strength and Conditioning: Biological Principles and Practical Applications. Cardinale, M., Newton, R., & Nosaka, K. (eds.). Hoboken, NJ: Wiley.
McNeal, J. R. & Sands, W. A. (2006) Stretching for Performance Enhancement. Current Sports Medicine Reports vol. 5, pp. 141-146.