Validation of an adjustment equation for the burst superimposition technique in subjects post-stroke

Introduction: Deficits in voluntary force generation may be due to incomplete activation or decreased maximum force-generating ability (MFGA) of the targeted muscle. The validity of techniques used to measure MFGA in individuals post-stroke has not been assessed. The objective of this study was to determine the reliability of the MFGA predicted using an adjusted burst superimposition method within a post-stroke population. Methods: Differences in paretic-side plantar flexor muscle MFGA between 2 trials was calculated using the standard and adjusted burst superimposition technique for 17 individuals post-stroke (15 men, 58.7 ± 10 years of age, ≥6 months post-stroke) to assess reliability of the techniques. Results: The adjusted measurement was shown to be more reliable (P = 0.03), especially when volitional effort differed by >40 N. Conclusions: Reliable measurement of the MFGA in individuals who have sustained a stroke is of clinical importance. These results suggest that the adjusted burst superimposition method may be useful when performing multiple measurements of muscle performance.