The effects of two stretching protocols on the reactive strength index in female soccer and rugby players

The purpose of this study was to investigate the effects of 2 stretching protocols on stretch-shortening cycle performance in female Division I soccer players and female club rugby players. Fifteen soccer and rugby players (20.1 ± 5.9 years, 170.5 ± 14.2 cm, 70.4 ± 22.3 kg) participated in 3 test sessions with different treatments. The first treatment involved a warm-up of 10 minutes of exercise on a cycle ergometer (warm-up only WO]), the second was this warm-up followed by static stretching (SS), and the third was this warm-up followed by dynamic stretching (DS). The treatments were administered randomly to negate an order effect. Each treatment was immediately followed by a reactive strength index (RSI) test requiring the athletes to drop off a box (45 cm in height) on to a force plate and upon landing immediately jump into the air while minimizing contact time (CT, milliseconds) and maximizing flight time (FT, milliseconds). The RSI was FT: CT. Repeated measures analysis of variance indicated that a significant treatment effect existed for RSI (F = 7.95, 2; p = 0.002) and FT (F = 7.43, 2; p = 0.003) but no significant effect for CT (F = 1.53, 2; p = 0.235). The RSI and FT were significantly greater in DS compared with that in SS and WO. Dynamic stretching is the preferred warm-up before an athletic event involving considerable jumping.