The acute effects of various types of stretching (static, dynamic, ballistic, and no stretch) of the iliopsoas on 40-yard sprint times in non-athletes

The purpose of this study was to determine the effect of static, ballistic, dynamic, and no stretching immediately prior to a 40-yard sprint in college students. There were 35 healthy subjects (22 male and 13 female) between the ages of 24 and 37 (Mean = 26.46 yrs, SD = 2.99 yrs) who participated. The experiment consisted of running 4, 40-yard sprint trials immediately following 1 of 4 different stretching protocols. Prior to each 40-yard sprint trial, a 5-minute warm up was performed at 3.5 mph on a treadmill. Each subject received each of the four techniques in a randomized order and ran a baseline sprint prior to each stretching protocol. In each protocol, subjects received one of four stretching techniques: ballistic, dynamic, static, no stretch and immediately ran a timed 40-yard sprint post stretch. The trials were completed within a 2 week time period allowing 48–72 hours between each trial. In the no stretch condition, subjects improved significantly from pre to post sprint times (p<0.0005). There were no statistically significant differences in pre and post stretch condition times among the static (p=0.804), ballistic (p=0.217), and dynamic (p=0.022) stretching conditions. These results could be due to the benefits of a dynamic warm up and also the negative impact of mechanical and neural effects of stretching. Sprint performance may show greatest improvement without stretching and through the use of a dynamic warm up.