Factors influencing thigh muscle volume change with cycling exercises in acute spinal cord injury - a secondary analysis of a randomized controlled trial.

Objective: To conduct a per-protocol analysis on thigh muscle volume outcomes from the Spinal Cord Injury and Physical Activity (SCIPA) Switch-On Trial.Design: Secondary analysis from an assessor-blind randomized, controlled trial.Setting: Four acute/sub-acute hospitals in Australia and New Zealand.Participants: 24 adults (1 female) within four weeks of motor complete or incomplete spinal cord injury (SCI)Intervention: Functional electrical stimulation-assisted cycling (FESC) or passive cycling (PC) 4x/week for 12 weeks.Outcome Measures: Whole thigh and muscle group volumes calculated from manually segmented MR images.Results: 19/24 participants completed ≥ twelve weeks of the intervention. Five participants experienced hypertrophy (4 FESC; 1 PC) and eight attenuation of atrophy (<20% volume loss) (3 FESC; 5 PC) in thigh muscle volume. Six participants were non-responders, exhibiting atrophy >20% (3 FESC; 3 PC). Mean (SD) change for FESC was -2.3% (25.3%) and PC was -14.0% (12.3%). After controlling for baseline muscle volumes, a strong significant correlation was found between mean weekly exercise frequency and quadriceps and hamstring volumes (r=6.25, P=0.006), regardless of mode. Average watts was highly correlated to quadriceps volumes only (r=5.92, P=0.01), while total number of sessions was strongly correlated with hamstring volumes only (r=5.91, P=0.01).Conclusion: This per-protocol analysis of FESC and PC early after SCI reports a partial response in 42% and a beneficial response in 25% of patients who completed 12 weeks intervention, regardless of mode. Strong correlations show a dose-response according to exercise frequency. Characteristics of non-responders are discussed to inform clinical decision-making.

Early exercise after spinal cord injury ('Switch-On'): study protocol for a randomised controlled trial.

BACKGROUND: Spinal cord injury (SCI) leads to a profound muscular atrophy, bone loss and bone fragility. While there is evidence that exercising paralysed muscles may lead to reversal of muscle atrophy in the chronic period after SCI, there is little evidence that exercise can prevent muscle changes early after injury. Moreover, whether exercise can prevent bone loss and microarchitectural decay is not clear. METHODS/DESIGN: A multi-centre, parallel group, assessor-blinded randomised controlled trial will be conducted. Fifty participants with acute spinal cord injury will be recruited from four SCI units in Australia and New Zealand. Participants will be stratified by site and AIS status and randomised to an experimental or control group. Experimental participants will receive a 12-week programme of functional electrical stimulation (FES)-assisted cycling. Control participants will receive a 12-week programme of passive cycling. The primary outcome is muscle cross-sectional area of the thigh and calf measured using magnetic resonance images (MRI) of the leg. Secondary outcomes include serum biomarkers of SCI osteoporosis (sclerostin, P1NP and ß-CTX), markers of immune function (IL-6, IL-10, FGF2, INF-γ, TNF-α), neurological function, body composition, depression and quality of life. Leg MRIs will be measured by a single blinded assessor based in Melbourne. Serum samples will be analysed in a central laboratory. All other characteristics will be measured at baseline and 12 weeks by blinded and trained assessors at each site. The first participant was randomised on 27 November 2012. DISCUSSION: The results of this trial will determine the relative effectiveness of a 12-week programme of FES-assisted cycling versus passive cycling in preventing muscle atrophy and maintaining skeletal integrity after spinal cord injury. TRIAL REGISTRATION: ACTRN12611001079932 (18 October 2011).