Subjects will then begin the exercise trial. Testing will be randomized so that subjects will perform protocols of either; a non-exercising control, concentric exercise or isometric exercise testing using all possible treatment sequences. Stratification for random sampling will be done using a block randomization scheme. For concentric testing, subjects will perform 5 sets of 20 reps at 30% MVC. When undergoing isometric exercise, subjects will perform 5 sets of sustained muscle contraction using the same duration of time it took to complete one set of 20 reps (as determined in pilot studies prior to initiation of this study). There will be a one-minute rest period between sets. Concentric testing will utilize a dumbbell with elbow flexion exercise. Isometric testing will be performed using a hand-grip dynamometer. Each exercise will be performed with the dominant arm/hand. Following exercise, subjects will also rate their perceived exertion and perceived muscle pain using the Borg Scale and Cook Scale, respectively. These are widely accepted and validated measures of perceived exertion and muscle pain. The control condition will consist of quiet rest for the same duration as the exercise conditions. At the end of the session, subjects will fill out two questionnaires: the State-Trait Anxiety Inventory and Situational Catastrophizing Scale. The validated questionnaires chosen to be completed at intake and post-testing will help to identify any confounding emotional or behavioral traits that may influence pain threshold and ratings.