iWalk Hands Free Crutch

The purpose of this study is to compare the hands free crutch (HFC) to standard axillary crutches (SACs) with and without a walking boot, using outcomes related to walking stability, balance confidence, patient preference, device comfort, and any reported pain while using the devices.

Healthy, able-bodied individuals will wear a walking boot to simulate a below knee injury or post-surgery condition during participation. They will maintain a non-weight bearing status while completing the 4 research conditions in randomized order: 1) BOOT, 2) HFC + BOOT, 3) SAC + BOOT, or 4) NONE.

Participants will complete 5 total sessions, with 4 biomechanics data collection sessions corresponding to the 4 conditions. At the first visit, participants will complete pre-consent screening and consent paperwork. Then they will be randomized to the 4 conditions above, and anthropometric (body height, weight/mass, leg length, shoe length and width) and demographic data will be collected. Participants will accommodate overnight to each of the 4 study conditions before testing. If participants are randomized to the NONE condition first, they will have the option of completing testing in that condition (no Boot) at the initial visit. The primary dependent measure is whole body angular momentum, an objective measure of walking stability.

Data will be collected using over 50 small reflective markers placed on the participants and the assistive devices, a computerized motion capture system and force plates embedded in the floor. The force plates capture ground reaction forces which will be used to calculate joint moments for interpretation of angular momentum data. The motion capture system will be used to evaluate joint and segment kinematics and temporal-spatial data to characterize the gait pattern in each condition and calculate angular momentum.

The second purpose of this research study is to determine the effect of crutch use on participant reported balance confidence and device preference. A validated balance confidence questionnaire and participant satisfaction, comfort and preference will be used to compare between conditions. A numerical pain rating scale (0-10) will be used to assess for any reported pain in all of the conditions.

The third purpose of this research is to determine the effect of crutch (HFC and SACs) and boot (with and without) use on walking stability as measured by whole body and segmental angular momentum during gait. Two additional conditions are added to address this purpose (HFC NO BOOT and SAC NO BOOT), resulting in a total of 6 research conditions:

• BOOT, 2) HFC + BOOT, 3) SAC + BOOT 4) NONE, 5) HFC NO BOOT, 6) SAC NO BOOT The HFC NO BOOT condition will be evaluated at the end of the HFC + BOOT session, and the SAC NO BOOT condition will be evaluated at the end of the SAC + BOOT session to stay within the fiscal and logistical constraints of the project. Previously described methods will be used.

Ultimately, this study could assist physical therapists and other providers in the clinical prescription and application of such devices.

Inclusion criteria

• Male or Female
• Ages: 18 - 45
• Height between 5'2" and 6'6"
• Foot size that corresponds to available walking boots
• Healthy individuals without current complaint of lower extremity pain, spine pain, open wounds or active infection
• Full active pain free range of motion of the bilateral upper and lower extremities and spine
• Able to hop without pain
• Able to perform a full squat without pain
• Able to walk up and down a flight of stairs at normal walking speed without using the hand rail
• Able to stand on one leg for at least 30 seconds
• Able to read and write in English and provide written informed consent

Exclusion criteria

• Weight greater than 270 lbs
• BMI greater than 35
• Maximum thigh circumference at top of the leg greater than 28"
• Prior medical or neuromusculoskeletal disorders that have limited their participation in work or exercise in the last 6 months
• Prior lower extremity injury proximal to the ankle requiring surgery or limiting function for greater than 6 weeks
• Prior back pain that recurs or has limited activities for greater than 6 weeks
• Diagnosed moderate or severe brain injury
• Diagnosis of a physical or psychological condition that would preclude testing (e.g. cardiac condition, clotting disorder, pulmonary condition)
• Uncorrected visual or hearing impairment(s)
• Require use of an assistive device
• Pregnancy - Per participant self-report. Due to the expected small number of pregnant individuals, and resulting inability to account for its effect on resulting outcomes, participants will be withdrawn from the study