How does LEAP work?

Study Timeline

Your involvement in the study will last for two years. There will be a total of 5 study visits which will happen every 6 months.

Each LEAP visit will involve the completion of questionnaires and blood sampling. In addition, you may undergo bone and muscle tests as well as accelerometry to look at your physical activity at enrollment, month 6, month 12, and month 24 visits.

Measuring Bone Strength: using pQCT/HR-pQCT

LEAP Study TimelineTwo modern machines will be used in the LEAP study to gather information on your child’s bone development. The first one is the pQCT or peripheral quantitative computed tomography scanner which measures the bone mineral density (BMD) of certain body parts such as your arms and legs.

It gives doctors and researchers an idea of how strong your bones are. It is completely painless and each scan takes no longer than 5 minutes to complete. For the LEAP study, both of your legs will be scanned in the pQCT machine.

Similar to pQCT, the second type of machine we are using is the HR-pQCT or high-resolution peripheral quantitative computed tomography scanner. It can scan your bones with greater detail and gives us a 3-dimensional look into the bone’s microstructure so we can assess your overall bone strength.


Measuring Muscle Strength: using a Leonardo plate



Subjects in the LEAP study will be asked to jump on a Leonardo Force Plate to measure their muscle strength. It is a simple platform that measures the amount of force exerted onto it when a person jumps. For the LEAP study, you will be asked to perform two-legged as well as one-legged jumps. The Leonardo plate takes the information from the jumps and transforms it into reproducible numerical measures and curves; this information can then be used to see changes over time in a single patient or to describe the muscle changes in a group of children with active arthritis.



Measuring Physical Activity: Accelerometry

A big component of the LEAP study is learning about children’s level of physical activity and how it is affected by their arthritis. To do this, we are using a device called an accelerometer (or step counter) to measure body movement and activity.  The accelerometer is a small unit, smaller than a cell phone, that attaches onto a belt or waistband.  Subjects will be asked to wear the accelerometer on their waist for seven days at various time points in the study. This will give us very accurate information of the amount of moderate or vigorous activity in your day, as well as the number of steps you take.