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ABSTRACT. Unick, J., H.S. Kieffer, W. Cheesman, and A. Feeney. The acute effects of static and ballistic stretching on vertical jump performance in trained women. J. Strength Cond. Res. 19(1):206-212. 2005.-Traditionally stretching has been included as part of a warm-up that precedes athletic participation. However, there is mixed evidence as to whether stretching actually enhances or hinders athletic performance. Therefore, the purpose of this study was to examine the acute effects of static (SS) and ballistic stretching (BS) on vertical jump (VJ) performance and to investigate whether power was altered at 15 and 30 minutes after stretching. Sixteen actively trained women performed a series of vertical jumps (countermovement and drop jumps) after an initial nonstretching (NS) session and after participating in BS and SS sessions that were conducted in a balanced and randomized order. The results indicated that there was no significant difference (p < 0.05) in VJ scores as a result of static or ballistic stretching, elapsed time, or initial flexibility scores. This suggests that stretching prior to competition may not negatively affect the performance of trained women.
KEY WORDS, flexibility, muscle tendon unit, power
INTRODUCTION
Flexibility is an important component to many athletic movements that should not be over-looked. Adequate flexibility requires that muscles and joints perform through a functional range of motion, which may lead to a decreased risk of injury (1, 13). Recently, there has been much debate as to whether stretching should be included as part of a proper warm-up preceding practice and competition or whether it is more beneficial to stretch during the cool-down phase of a workout (15, 16, 30). According to the Holcomb (13) and the American College of Sports Medicine (ACSM) (1), stretching before or after competition are both acceptable practices. Moreover, the National Strength and Conditioning Association (NSCA) guidelines (13) state that stretching before competition will improve performance and functional abilities. Despite inconclusive evidence from recent studies, stretching prior to practice or competition is still commonly recommended (27).
Some of the factors that can influence flexibility are the frequency, duration, and intensity of stretching. Even within these areas of flexibility prescription, there is much debate about how a stretching routine should be performed. The NSCA (13) believes that the ideal amount of time to...