The objective of this study is to compare to different methods of measuring the size of calf muscles: magnetic resonance (MRI) and ultrasound imaging. Participant will undergo a MRI scan (about 1 hour) and an ultrasound imaging session (about 1 hour). Images obtained from patients with Achilles tendon rupture will also be used to determine the feasibility of quantifying damage to the soleus muscle.

After you accept participating demographic questions will be asked. You will also be asked standard MRI safety/screening questions. These questions are used to determine that it is safe for you to participate in MRI research. You will be asked to leave metal objects and personal belongings and to remove any articles of clothing with metal before entering the MRI room. Please ask the experimenter if you are unsure about any items. If it is safe, an MRI will be performed on your leg. Additionally, several images will be taken from your leg using ultrasound. The ultrasound and MRI sessions can be performed the same day or in different days depending on your preference. Depending on scheduling constraints at the MRI facility, you may be scheduled for the ultrasound session first.

You will receive $25 after completing the MRI and $25 after completing the ultrasound imaging sessions.