This study is designed to evaluate the feasibility, wearability and participant satisfaction of novel outcome assessment tools in DMD patients which are performed in the home environment.

This is a low interventional feasibility study to evaluate the use of:

1. An FDA 510(k) cleared Class II wearable medical device designed to collect medical grade, clinical quality biometric, physiological and other electronic clinician outcome assessments data in a clinical trial setting, and;
2. The Duchenne Video Assessment (DVA) tool to evaluate the quality of movement in patients with Duchenne Muscular Dystrophy (DMD)

This study will provide data on suitability of these tools in future clinical trials.

Inclusion Criteria:

For DMD patients:

1. Parent/guardian or participant is able to give informed consent and/or assent as required by local regulations, and all are willing and able to comply with the protocol.
2. Participant is assigned male sex at birth and is age 4 to <13 years at time of consent.
3. Participant has a confirmed diagnosis of DMD based on genetic testing and/or clinical records consistent with the diagnosis.
4. Participant has been on a stable glucocorticoid dose for 3 months prior to participation.
5. Participant is ambulatory as defined by the ability to walk down a hallway at home without assistance or support.

For healthy age-matched controls:

1. Parent/guardian or participant is able to give informed consent and/or assent as required by local regulations, and all are willing and able to comply with the protocol.
2. Participant is assigned male sex at birth and age 4 to <13 years at time of consent.

Exclusion Criteria:

For DMD Patients:

1. Participant is/was enrolled in any interventional study for DMD in the past 3 months or has ever been enrolled in a gene therapy study.
2. Participant is on any approved therapy for DMD except for glucocorticoids.
3. Participant is currently or was previously treated with exon-skipping antisense oligonucleotides such as eteplirsen, golodirsen, casimersen, and viltolarsen.
4. Participant has any prior or ongoing medical condition, medical history, or physical finding that could affect the participant's ability to perform the study assessments.
5. Participant has had major surgery within 3 months prior to recruitment or planned orthopedic surgery for any time during this study which would interfere with the ability to perform assessments.
6. Participant has a history of allergic response to silicones or adhesives.
7. Participant has an active implanted device (e.g., pacemaker). Implanted devices relying on an electrical power source to function are considered active devices.

For healthy age-matched controls:

1. Participant has a known musculoskeletal disease or had a musculoskeletal injury in the past 3 months.
2. Participant has other illness that precludes functional testing.
3. Participant is enrolled in any interventional study.
4. Participant has or has had any prior or ongoing medical condition, medical history, or physical finding that could affect the participant's ability to perform the study assessments.
5. Participant has had major surgery within 3 months prior to recruitment or planned orthopedic surgery for any time during this study which would interfere with the ability to perform study assessments.
6. Participant has a history of allergic response to silicones or adhesives.
7. Participant has an active implanted device (e.g., pacemaker). Implanted devices relying on an electrical power source to function are considered active devices.

Approximately twenty ambulatory males aged 4 to <13 years with DMD will be recruited. Of these, approximately 10 participants will be considered Early Ambulatory and 10 will be considered Late Ambulatory. Early ambulatory is defined as able to get off the floor without assistance or use of furniture.

Approximately twenty healthy, age-matched controls will be recruited.