Potential Factors Influencing Heart Rates During Locomotor Training Poststroke and Their Associations With Locomotor Outcomes

BACKGROUND AND PURPOSE: Previous studies suggest targeting higher heart rates (HRs) during locomotor training improves locomotor outcomes (ie, walking speed and distances) in individuals poststroke. However, those who walk slower or are prescribed β-adrenergic antagonists (β-blockers) may not achieve targeted HRs. The purpose of this study was to evaluate the contributions of these patient-related variables on the ability to achieve targeted HRs during graded exercise testing (GXT) or locomotor training, and their effects on locomotor outcomes. METHODS: This secondary analysis of a randomized trial enrolled 90 individuals >6 months poststroke assigned to either high-intensity training targeting >70% HR reserve (HRR) or low-intensity training (<40% HRR). Associations between baseline walking speeds and distances or β-blocker use versus HRRs during GXTs and training were identified. Subsequent analysis focused on whether training HRs or ratings of perceived exertion (RPEs) were related to changes in walking speeds/distances. RESULTS: Achieving higher HRRs during GXTs was related to faster peak treadmill speeds (r = 0.60, P < 0.01) and β-blockers use (r = -0.23, P < 0.05). However, training HRRs were unrelated to initial locomotor outcomes, with depressed HRRs in those using β-blockers. Only 40% of participants averaged >70% HRRs during high-intensity training. Regression analysis suggested training HRRs were related to walking speeds/distances only in those without β-blockers, while RPEs were correlated regardless of β-blocker use. Analysis of changes in walking speeds/distances indicates no differences in those able or unable to achieve targeted HRRs. DISCUSSION AND CONCLUSION: Achieving targeted HRRs was not a primary determinant of locomotor outcomes, although attempts to achieve higher intensities and use of RPEs may be helpful.