INTRODUCTION

Strong abdominal muscles are essential for postural stability, balance and the prevention of lower back pain (Halpern et al., 1979). There are a vast number of devices on the current market, such as the "Ab-Trainer", that claim to provide the user with sufficient and efficient progress with respect to strengthening the abdominal muscles. The "Ab-Trainer" is a device used to assist in the performance of an abdominal "crunch" from the supine position. The user's head is supported by the device as it assists in raising the shoulders and upper back off of the floor. A therapeutic device used to strengthen the abdominal muscles is the "Swiss Ball." The "Swiss-ball" supported "crunch" is performed while lying supine over top the ball so that only the lower spine is supported. Is the therapeutic device a more effective method for strengthening the abdominal muscles than performing conventional abdominal "crunches" using a trendy "Ab-Trainer?"

The purpose of this investigation is to provide a biomechanical comparison between the "Ab-trainer" assisted "crunch" and the "crunch" performed upon the therapeutic device known as the "Swiss Ball." Our analysis will determine which exercise is more effective in strengthening and conditioning the abdominal muscles. The group is interested in this topic because the abdominal muscles serve as a core muscle group and as such they play a crucial role in injury prevention and the overall success with athletic performance and exercise.