People with hypermobile Ehlers-Danlos Syndrome/Hypermobility Spectrum Disorder (hEDS/HSD) often have pain, coordination problems, and low tolerance to activity and exercise. There is a publicly available on-line, independent Pilates program designed specifically for this population. This research project proposes to measure pain, function, and common symptoms in individuals before and after 8 weeks of using this on-line Pilates module, and will follow up 6 months later, and compare to an 8-week wait-list control group.

The intervention is provided through an on-line Pilates module commercially available at https://jeanniedibon.com/strengthen-your-hypermobile-core/. "Strengthen Your Hypermobile Core" has 5 modules. Subjects will be asked to complete the modules in order, as the modules build upon one another. However, subjects may repeat any modules at any time, with the goal of completing all 5 modules within the 8 week period. This allows subjects the flexibility to customize their participation by using the modules they feel are most helpful. Users who typically access this Pilates course have this same flexibility so, while it adds variability to the intervention, it better reflects how the program is actually used.

Subjects will be asked to do their Pilates practice while watching the videos (not from memory) to ensure that they are performing techniques optimally. Each module lasts 25 minutes, but includes some resting activities so modules are not vigorous or fatiguing for most people. Nonetheless, subjects will be instructed to omit activities that they feel they cannot do safely. Subjects can pause a session to add more rest breaks, if needed, or stop and complete a session later. Subjects will commit to doing 3 Pilates modules per week, for a total of 75-90 minutes/week (depending on the exact length of the modules they do).

Subjects will complete questionnaires before starting the on-line Pilates modules. Completing these questionnaires on SurveyMonkey is likely to take 30-45 minutes.

The study initially aimed to include a total of 100 participants, but more than 800 signed up within the first 2 weeks, and another 200 over the following months. The design was therefore modified to have the first 300 participants start the Pilates immediately, and the remaining participants begin after an 8-week waiting period. In addition to adding a control group, the wait-list prevented us from having to turn people away from free access to the exercise program, and from our being overwhelmed by too many participants. Because subjects were not randomly assigned and the intervention could not be directly monitored, the study is a pragmatic clinical trial.

Inclusion Criteria:

• i. Have some form of Hypermobility Spectrum Disorders or hypermobile Ehlers-Danlos syndrome (HSD/hEDS) diagnosed by any health care provider; this would include individuals diagnosed with Joint Hypermobility Syndrome using the pre-2017 diagnostic criteria.

ii. Able to read the English language and understand spoken English. iii. Willing to try to do Pilates using the 25 minute on-line training videos at least 3 times per week, unless they experience some adverse event or illness that prevents them from safely participating.

Exclusion Criteria:

• i. Medical restrictions (such as recent and healing surgery, fractures, comorbidities such as severe rheumatoid arthritis or neurological conditions, etc.) that prevent them from safely doing gentle exercise lying down on the floor, sitting, and standing.

ii. Inability to safely stand (with or without using upper extremity for balance) for 10 consecutive minutes.

iii. Recent injuries or changes in status that are not stable. This will be defined as "A significant change in your wellness due to recent injury or new symptoms in the past month that result in your wellness during the past month being very different from the past 5 months. Flare episodes that are typical for you will not prevent you from participating at this time." iv. Significantly changed treatment approach or medication within the past 3 months or be expecting to change their treatment program (including medication changes) during the study. This would make it difficult for us to know if changes are due to the Pilates class or the change in their treatment program. However, we understand that their health status may change such that they need to change their health care routine for physical and mental health.

v. Currently receiving regular rehabilitation such as physical therapy, or having received physical therapy (PT) or a similar movement-based therapy (such as such as Pilates, Feldenkrais, Tai Chi, qigung, yoga) in the past 3 months. Individuals who continue to do exercises from any of these sources are not excluded, as these individuals should be stable on their current routine.

vi. Currently doing more than 30 minutes/week of Pilates exercise.

Hope to share data.

Masking is not practical for an exercise intervention.