Spinal cord injury (SCI)-related paraplegia is a complex neurological condition characterized by motor impairment, increased spasticity, and significant functional limitations in daily activities. Spasticity is one of the most common secondary complications after upper motor neuron lesions and can negatively affect rehabilitation outcomes, gait ability, and functional independence.

This randomized controlled study aims to investigate the effects of Functional Electrical Stimulation (FES) applied to the quadriceps muscle in individuals with paraplegia. Participants will be randomly assigned to either a control group receiving conventional neurorehabilitation or an intervention group receiving additional FES treatment.

The primary outcomes include changes in spasticity level, quadriceps muscle strength, and functional mobility. Spasticity will be assessed using the Modified Ashworth Scale (MAS), muscle strength will be evaluated with Manual Muscle Testing (MMT), and functional mobility will be measured using the Spinal Cord Independence Measure (SCIM), Timed Up and Go Test (TUG), and 6-Minute Walk Test (6MWT).

The intervention period will last 8 weeks, with standardized rehabilitation programs applied to both groups. The FES group will additionally receive quadriceps stimulation with specific neuromuscular electrical stimulation parameters.

The findings of this study are expected to provide evidence regarding the effectiveness of FES as an adjunct to conventional rehabilitation in improving motor function and functional independence in individuals with paraplegia.

Spinal cord injury (SCI) is a major cause of long-term disability worldwide, often resulting in paraplegia when the thoracic, lumbar, or sacral spinal segments are affected. Individuals with paraplegia commonly experience significant impairments in voluntary motor control, muscle weakness, spasticity, and reduced functional mobility, all of which contribute to decreased independence in activities of daily living.

Spasticity, defined as a velocity-dependent increase in muscle tone due to hyperexcitability of the stretch reflex, is one of the most frequent complications following upper motor neuron lesions. Although spasticity may occasionally contribute to functional stability, excessive spasticity often interferes with voluntary movement, gait training, and rehabilitation outcomes (Pandyan et al., 2005).

Functional Electrical Stimulation (FES) is a neurorehabilitation technique that delivers electrical impulses to peripheral nerves to evoke functional muscle contractions. It facilitates neuromuscular re-education, enhances motor unit recruitment, and may promote neuroplasticity in the central nervous system. Previous studies have demonstrated that FES can improve muscle strength, walking ability, and functional independence in individuals with neurological impairments (Sheffler & Chae, 2007; Kesar et al., 2010; Hesse et al., 2003).

This study is designed as a prospective, single-center, parallel-group, randomized controlled trial conducted in accordance with CONSORT 2010 guidelines. A total of 60 participants with paraplegia secondary to spinal cord injury will be enrolled and randomly allocated into two groups:

Control Group: Standard neurorehabilitation program only Intervention Group: Standard neurorehabilitation program + FES applied to the quadriceps femoris muscle The rehabilitation program will be conducted 3 days per week for 8 weeks and will include stretching exercises, strengthening exercises, balance training, and transfer training. In the intervention group, FES will be applied 5 days per week for 8 weeks with the following parameters: 35 Hz frequency, 300 µs pulse duration, and 10 seconds on / 20 seconds off cycle.

Outcome assessments will be performed at baseline (week 0) and after intervention (week 8). Spasticity will be evaluated using the Modified Ashworth Scale (MAS), which is widely used in clinical practice for assessing muscle tone in neurological conditions. Quadriceps muscle strength will be measured using Manual Muscle Testing (MMT) based on the Medical Research Council (MRC) scale. Functional mobility and independence will be assessed using SCIM, TUG, and 6MWT.

SCIM is a validated scale specifically developed for individuals with spinal cord injury and assesses self-care, respiration and sphincter management, and mobility domains. TUG test provides an objective measure of functional mobility and fall risk, while 6MWT evaluates functional exercise capacity and endurance.

The primary hypothesis of this study is that FES combined with conventional rehabilitation will significantly reduce spasticity, improve quadriceps muscle strength, and enhance functional mobility compared to conventional rehabilitation alone.

The results of this study are expected to contribute to the evidence base regarding the clinical effectiveness of FES in neurorehabilitation and may support its integration into standard rehabilitation protocols for individuals with paraplegia.

Inclusion Criteria:

• Participants will be included in the study if they meet all of the following criteria:
• Aged between 18 and 65 years
• Diagnosed with spinal cord injury resulting in paraplegia (traumatic or non-traumatic etiology)
• Classified as ASIA Impairment Scale C or D
• Medically stable condition
• Presence of lower extremity spasticity (Modified Ashworth Scale ≥ 1)
• Ability to understand and follow simple instructions
• Willingness to participate and provide informed consent

Exclusion Criteria:

• Participants will be excluded if they present any of the following conditions:
• Presence of cardiac pacemaker or implanted electrical device
• Severe cognitive impairment or communication difficulties preventing participation
• Active infection or systemic inflammatory condition
• Severe lower extremity contractures or deformities limiting movement
• Dermatological conditions or open wounds preventing FES application
• History of severe autonomic dysreflexia triggered by electrical stimulation
• Uncontrolled medical conditions that may interfere with participation or safety

The fully anonymized individual participant data (IPD) obtained in this study will be shared with appropriate researchers upon reasonable request following the publication of primary results. Data sharing will be carried out in accordance with institutional ethics committee regulations and applicable data protection laws.

Outcome assessors will be blinded to group allocation to reduce assessment bias. Participants and care providers will not be blinded due to the nature of the intervention (FES application).