The effects of reactive balance training on cardiorespiratory fitness and muscle strength: a pilot randomized controlled trial

BackgroundReactive balance training (RBT) may improve multiple components of physical fitness, including aerobic capacity and muscle strength. However, there have been no studies examining its effects on these factors in people with stroke. ObjectivesThe objectives of this pilot study were to determine the feasibility of a non-inferiority randomized controlled trial, comparing aerobic and strength training (AST) and RBT, considering sample size (primary objective), rates of accrual and withdrawal, intervention adherence, missing data, preliminary effects, and harms (secondary objectives). MethodsPeople who were at least six months post-stroke and could stand independently for >30 seconds were recruited. Peak oxygen consumption [Formula] was measured by cardiopulmonary exercise test. Peak isokinetic torques for knee extension and flexion were measured by dynamometer. ResultsTwenty-three participants (6 women) were randomized into AST and RBT groups. Four-hundred participants per group were estimated to be required for the main trial considering [Formula] and peak isokinetic torque as primary outcomes. Rates of accrual and withdrawal were 2 participants for every quarter and 30%, respectively. On average, AST participants attended 29.6/36 sessions (range: 18-36) and RBT participants attended 23.5/36 sessions (range: 1-35). Data were missing for [Formula] (n=2) and ABC scale (n=1) as participants declined testing. [Formula] and peak knee extension torque of more-affected legs improved post-intervention in both groups. Ten adverse events related to study interventions resolved without medical attention. ConclusionProgressing to a definitive single-site trial is not feasible given the large required sample size, low accrual, and high withdrawal rates. Trial registrationNCT04042961