Acute Effects Of Short-Term Static, Active Isolated, And Dynamic Stretching Protocols On Explosive Power and Hamstring Flexibility in Active Males

Stretching is commonly used in warm-up routines, yet evidence regarding its acute effects on flexibility and explosive performance remains mixed, particularly when considering technique, duration, and tempo. This study compared the immediate and short-term effects of static stretching (SS), active isolated stretching (AIS), and dynamic stretching (DS) protocols with different tempos and durations on hamstring flexibility and countermovement jump (CMJ) performance in active males. Thirty healthy, physically active men (22–25 years; body mass index (BMI) < 30 kg·m⁻²), each with at least two years of resistance-training experience, completed a randomized cross-over design involving six stretching conditions: SS (30-s passive stretch), AIS (30-s total active contractions), and four DS variations combining tempo (100 or 150 beats/min) and duration (30 or 75s): DS100/30, DS150/30, DS100/75, and DS150/75. Hamstring flexibility was assessed using the Passive Straight-Leg Raise test, and CMJ height and power were measured using a Swift Performance Speed Mat. Measurements were obtained before stretching and immediately, 5 minutes, and 10 minutes afterward. Repeated-measures ANOVA and paired t-tests were used (p < .05). All stretching protocols significantly improved flexibility (p < .05), with the greatest improvements following DS150/30 and AIS. CMJ height and power increased at all post-stretch time points for DS150/30, AIS, and DS100/30 (p < .05), whereas longer DS durations (75 s) did not enhance performance. Short-duration, high-tempo dynamic stretching (150 bpm, 30 s) produced the most effective acute improvements in flexibility and explosive power. These findings emphasize the importance of stretch duration and tempo when designing warm-up routines.