Table 1 Study outcome measures

Aim 1 Primary outcome: to examine the efficacy of RGT dose

 Walking Index for Spinal Cord Injury -II (WISCI-II)

Our primary outcome, the WISCI-II defines the physical limitation for gait secondary to impairment at the person level and indicates the ability of a person to walk after SCI [12]. Intrarater and interrater reliability are excellent at 1.0 and 0.98 respectively [13].

Aim 1 Secondary outcomes

 Gait speed via 10-Meter Walk Test (10MWT)

Gait speed (m/s) is correlated with mobility in the community, capacity to perform activities of daily living, risk of falls, re-hospitalization, and risk of cognitive decline [14]. A change of > 0.06 m/s is considered to exceed minimally clinically important difference (MCID) [15] and test–retest reliability is excellent (ICC = 0.97) [16].

 Spinal Cord Independence Measure (SCIM)

The SCIM assesses self-care management, respiration and sphincter management, and functional mobility after a SCI. With excellent interrater reliability (r= 0.90) [17], the SCIM is reported to be more sensitive to functional changes than the FIM [18].

 Numerical Pain Rating Scale (NPRS)

A 0–10 Point Numerical Pain Rating Scale (NRS) is recommended as the outcome measure for pain intensity after SCI [19] during acute and subacute phases.

 Fatigue Severity Scale (FSS)

The Fatigue Severity Scale (FSS) [20] measures the effects of fatigue on function. The FSS has acceptable reliability with regard to internal consistency, test–retest reliability, and validity in persons with SCI [21].

 Penn Spasm Frequency Scale (PSFS)

The PSFS assesses a person’s perception of spasticity frequency and severity following a SCI [22] and demonstrates excellent internal consistency (ICC = 0.90) [23].

 Patient Health Questionnaire—9 (PHQ-9)

The PHQ-9 assesses the presence and intensity of depressive symptoms. For SCI, the PHQ-9 demonstrates excellent internal consistency (Cronbach’s alpha = 0.87) [24].

 Life Satisfaction Questionnaire (LiSAT-9)

The LISAT is a nine-item quality of life questionnaire suitable for SCI populations containing a single item assessing overall life satisfaction, along with eight additional domain-specific items [25].

 Physical activity

Actigraph GT9x (Actigraph LLC, Pensacola, FL, USA) is reported to accurately measure steps in people with incomplete SCI during rehabilitation [26]. At each assessment period, the participant will also be given an Actigraph device to wear for the following 7 days.

Aim 2 Outcomes: To determine the neuroplastic effect of dosing RGT

 Transcranial magnetic stimulation (TMS)

TMS will be utilized to capture motor thresholds and MEP amplitudes from the TA, RF, and FDI muscles and be used to index corticospinal excitability. A lower motor threshold and greater MEP amplitude suggest an increased excitability. We will compute the slopes of the recruitment curves constructed for TA and RF. A flatter slope of the recruitment curve suggests a less efficient corticospinal recruitment pattern [27].

Aim 3 Outcomes: To evaluate the feasibility of delivering RGT across inpatient to outpatient rehabilitation settings

 Safety, tolerability, and feasibility

Safety, tolerability, and feasibility of RGT treatment will be measured across inpatient and outpatient practice settings. Metrics include safety (rate of adverse events), tolerability (visual analog scale of tolerability, heart rate, perceived exertion, number of steps), and feasibility (treatment completion rate).