A substantially hollow practice bat is disclosed, and is useable by baseball players and other athletes in training and/or rehabilitation sessions to develop stronger and more precise swinging habits. A user typically stands in a pool of water approximately chest-deep. He or she swings the device in an approximation of a proper swing for the sport. The device includes holes that tend to minimize turbulence that a standard bat would generate, yet provides both resistance and good haptic feedback to the user. These features develop or redevelop strength and consistency in the user's swing. Analogous training benefits are obtained for many activities, such as batting, golfing, and tennis.