This is a prospective observational study looking at gait-cadence in older adults who are scheduled to have major abdominal surgery at the University of Chicago. The objective of the study is to evaluate whether gait-cadence, as measured from a patient's mobile device at-home, can provide an accurate assessment of a patient's functional status prior to major abdominal surgery and identify patients at risk of poor functional outcomes.

Over 100,000 older adults undergo elective major abdominal surgeries in the US each year and many experience loss of mobility after surgery that requires post-acute care. Risk of mobility loss is greater for older adults unable to engage in moderate-intensity physical activity before surgery. Additionally, recovery trajectories to baseline mobility remains poorly understood for older adults and may impact readmission. Functional status assessment before surgery can identify interventions to help older adults improve walking capacity and improve recovery trajectories after surgery. However, almost no patients receive objective functional status tests before surgery due to logistical and practical barriers. Remote assessments performed independently by the patient using wearable technology, such as smartphones, may provide a solution. Smartphone accelerometers combined with open-source software can directly measure a patient's gait-cadence, or the number of steps taken per minute. This observational cohort of older adults undergoing major abdominal surgery will use a novel smartphone application to obtain remotely collected gait-cadence from usual and fast paced walks prior to their in-clinic visit. Investigators will then compare the at-home to the in-clinic usual and fast paced walks and measure their recovery trajectory after surgery through weekly at-home walks. Overall mobility will be assessed using ActiGraph accelerometers worn for a 7-day time period before and after surgery. The investigator's hypothesis is that gait-cadence measured during usual and fast pace walks at-home will 1) provide an accurate and easy to use functional assessment 2) identify patients at-risk of mobility loss and 3) determine walking recovery trajectories for older adults after surgery. Results from this study will provide important knowledge on mobility trajectories of older adults after major abdominal surgery and develop a novel approach to identify high-risk older adults. Further, this platform may be leveraged to deliver mobility interventions before surgery to improve patient outcomes after surgery.

Inclusion Criteria:

• Patients > or = 60 years of age and scheduled for surgery.
• Access to a safe walking space roughly 30 ft in length. Safe walking spaces include a long hallway in the home, common use hallway in an apartment building or outside public area.
• Able to walk independently with or without an assistive device (e.g. cane or walker)

Exclusion Criteria:

• Inability to walk independently
• Surgery scheduled less than 7-days after APMC appointment
• Patients scheduled for orthopedic surgery
• Patients scheduled for neurological surgery
• Patients scheduled for cardiac surgery
• Non-English speaking.

Patients who are 60 years or older who have surgery scheduled at University of Chicago that can walk independently with or without an assistive device.