Investigating the accuracy of manual muscle testing to distinguish false from true statements, using different levels of blinding

This study is not testing the effectiveness of an intervention, but the accuracy of an assessment tool. Manual Muscle Testing is an assessment tool used by an estimated 10 million practitioners worldwide. In this study the anterior deltoid muscle will be tested to see if it can withstand a given force (into extension) applied by a healthcare practitioner. During one MMT, the patient's arm will be held at 90 degrees of anterior flexion for a period not exceeding 5 seconds. Each patient will undergo no more than 30 MMTs in total over the course of about 30 minutes (i.e. 1x 5-sec MMT per minute). It is expected that one data collection session will take no more than 30 minutes. Data collection will take place over two (2) years: September 2009 to August 2011 - or when our sample size has been acheived, whichever comes first. It has been previously reported that a patient will not be able to resist the downward force after speaking an incongruent statement, and can easily resist the force after speaking a congruent statement. In that study, as in this one, a congruent statement is defined as one which the patient believes is true, and an incongruent statement is one that the patients believes is false. In this study, the patient will be asked to speak statements which are true and statements which are false. In all cases, the patient will know whether the statement is true or false. However in some cases, the practitioner will be unaware if the statement spoken by the patient is true. (That is, the practitioner will be blind in some cases.) Also, in some cases, the patient will be aware that the practitioner knows that verity of the statement, and in some cases, the patient will not know if the practitioner knows the verity of the statement. (That is, in some cases, the patient will be blind to the practitioner’s blindness.)