Cardiometabolic Disease (CMD) is the silent killer within the spinal cord injury/disease (SCI/D) population. Many SCI/D patients' initial CMD presentation is with a heart attack, stroke, or sudden cardiac death, highlighting the need for interventions to reduce CMD risk. CMD contributes to 46% of deaths, with 30-50% of the SCI/D population living with undiagnosed CMD. Treating CMD risk is more challenging in the SCI/D population due to prolonged inactivity, inability to exercise, and excessive caloric intake to expenditure ratio. Identifying accessible and inclusive strategies to combat CMD risk in the SCI/D population is a compelling and urgent health priority.

Blood flow restriction (BFR) exercise involves applying inflatable cuffs to the proximal end of an individual's limbs. Changes to the amount of blood flowing into and out of the limb lead to a low oxygen environment within the limb, shifting the way the muscles can produce the energy required to function, increasing the benefits of low- and moderate-intensity exercise. Coupling BFR with Functional electrical stimulation cycling (FES-cycling), a commonly used rehabilitation tool within the SCI population, could improve FES-cycling's short- and long-term benefits without reducing the accessibility and inclusiveness of long-term exercise prescription. Although preliminary BFR research in the SCI/D has identified positive muscular improvements, whether FES-cycling coupled with BFR can be safely prescribed or feasibly implemented long-term within the SCI/D population is unknown.

The proposed project aims to determine the safety and feasibility of FES-cycling coupled with BFR for 20 minutes of moderate-intensity exercise among adults with chronic spinal cord injury/disease (SCI/D). The research team aims to implement pre-test, eight exercise sessions, and post-test across 6-weeks. Criteria for success include no adverse or severe adverse events not alleviated by ceasing exercise (safety), a 1 to 8 ratio of participants screened to participants eligible (recruitment success), and participants successfully completing all exercise sessions (participant retention).

Background Spinal cord injury/disease (SCI/D) is a highly debilitating condition that results in motor, sensory, autonomic, and autoimmune impairments, which dramatically alters the individual's mobility, life, and health. Following injury, the individual's health is compromised by their primary impairment and secondary health conditions. Cardiometabolic Disease (CMD) refers to a collection of interrelated conditions (e.g., insulin resistance, chronic inflammation, and obesity) that increase the risk of cardiovascular and metabolic disease. CMD disease contributes to 46% of deaths within the SCI/D population. Currently, limited rehabilitation strategies exist that can effectively combat CMD risk factors among individuals living with an SCI/D. Therefore, identifying accessible, inclusive, and safe rehabilitation strategies to combat CMD risk among individuals living with an SCI/D is a compelling and urgent health priority.

Study Aim and Rationale The proposed project aims to investigate the safety and feasibility of functional electrical stimulation cycling (FES-Cycling) coupled with blood flow restriction (BFR). Preliminary studies examining BFR exercise within SCI/D individuals have reported positive findings. However, the pioneering BFR exercise research has not prescribed moderate-intensity aerobic exercise that mirrors the SCI/D weekly exercise guidelines. Therefore, whether BFR can be tolerated safely and practically in the SCI/D population is unknown.

Methods The proposed pilot study will utilize a convergent mixed methods approach and implement a pretest-post test quasi-experimental design. Six adults (18-75yrs) with chronic (>1yr) SCI/D will be recruited to participate in two testing sessions (pre/post), four FES-Cycling exercise sessions, and four FES-cycling coupled with BFR sessions across six weeks. Measures of safety, participant recruitment, and retention will be collected. A criterion of success will be developed for each measure. Descriptive statistics will be calculated and compared to the prior-defined success criterion. Deductive and inductive content analysis will assess participant feedback regarding exercise modality and protocol implementation.

Anticipated Results The research team expects to accomplish the success criteria for all measurement categories based on the existing evidence across the domains of FES-cycling and BFR exercise within SCI/D. Analysis of participant feedback will direct future protocol development and BFR prescription parameters.

Conclusions The proposed project is the first step towards developing a low-cost, highly accessible exercise accessory that could potentially maximize the physiological yield of aerobic and resistance exercise, increasing the potential protective abilities of exercise against CMD risk.

Inclusion Criteria:

• Adult (≥ 18 to ≤ 75yrs)
• Male or female
• Chronic Injury (>1yr)
• Diagnosis of SCI at levels between C5 to T10 (AIS A-D) with traumatic or non-traumatic etiology.
• ≥3 Cardiometabolic risk parameters

Exclusion Criteria:

• A prior or current history of venous thromboembolism
• Pressure injury of the pelvis, mid to upper thigh region, or foot
• Managing a lower limb fracture
• Any history of embolic stroke
• Myocardial infarction
• Current untreated hypertension
• Language, psychiatric, cognitive, or communicative disability (e.g., traumatic brain injury) that compromises the participant's autonomy to voluntarily join the study, follow its instructions and/or operate the device.
• Current alcohol or street drug use disorder.
• Current use of an anticoagulant medication.
• Frequent episodes of autonomic dysreflexia unresponsive to therapy (e.g., 3-5 times a week).
• Unresolved deep vein thromboembolism (VTE) in the past six months.
• Severe spasticity preventing the necessary range of motion for cycling.
• Active implantable medical device (e.g., pacemaker, ITB pump).
• Inability to provide informed consent.
• Severe active concurrent medical conditions (e.g., skin or respiratory infections, lung, pressure sores).
• Unstable spine or unhealed limbs or pelvic fractures.
• Active heterotopic ossification interfering with the lower extremity range of motion.

Summary data of the primary variables