Does controlling force and orientation when using real time ultrasound imaging improve reliability of measuring transverse abdominis in experienced and novice clinicians?

The thickness and activation of patient's transverse abdominis (TrA) will be measured using real time ultrasound imaging (RTUI) and the reliability of these measures examined. This will be measured using a device that controls for the force and orientation of the probe (force probe device). The force probe device measures the force, inclination and roll of the US probe and displays these values on a laptop screen. The examiner can then increase/decrease the force applied through the probe to maintain a consistent amount of pressure. Images are later collected from video files at time points in which the force, inclination and roll match. Data collection will be conducted by both an experienced and an inexperienced examiner. The experienced examiner is a physiotherapist with 23 years clinical experience, a level 2 postgraduate RTUI certificate, 6 years experience in measurement using musculoskeletal RTUI (last 5 measuring TrA and LM). The inexperienced examiner is a fourth year physiotherapy student with 6 hours of training and hands on practice in using RTUI to measure TrA using the force probe device with the experienced examiner and another student who previously completed his honours project using the same equipment. 2-3 sessions of free practice are also planned. Participants will be taught to contract their TrA prior to data collection. Participants will be required to remove their shirt and may be required to lower their pants to expose the top of the pelvis for TrA. Participants will lie on their back with their hips and knees bent to measure TrA. An adhesive tape marker will be used to mark where the ultrasound probe will sit. Videos will be collected using RTUI in movie mode for later analysis. Two videos will be taken of each muscle using the force probe device: a video with the muscle at rest for approximately 20 seconds and a video in which the participant contracts the muscle twice will be captured. The participant will then have the same videos captured again to determine reliability of measurement.