Bacurau, RFP, Monteiro, GA, Ugrinowitsch C, Tricoli, V, Cabral, LF, Aoki, MS. Acute effect of a ballistic and a static stretching exercise bout on flexibility and maximal strength. J Strength Cond Res 23 (1): 304-308, 2009-Different stretching techniques have been used during warm-up routines. However, these routines may decrease force production. The purpose of this study was to compare the acute effect of a ballistic and a static stretching protocol on lower-limb maximal strength. Fourteen physically active women (169.3±8.2 cm; 64.9±5.9 kg; 23.1±3.6 years) performed three experimental sessions: a control session (estimation of 45 leg press one-repetition maximum [1RM]), a ballistic session (20 minutes of ballistic stretch and 45 leg press 1RM), and a static session (20 minutes of static stretch and 45 leg press 1RM). Maximal strength decreased after static stretching (213.2±36.1 to 184.6±28.9 kg), but it was unaffected by ballistic stretching (208.4±34.8 kg). In addition, static stretching exercises produce a greater acute improvement in flexibility compared with ballistic stretching exercises. Consequently, static stretching may not be recommended before athletic events or physical activities that require high levels of force. On the other hand, ballistic stretching could be more appropriate because it seems less likely to decrease maximal strength.