Tamaya Van Criekinge, PT
@TamayaVC
Recovery of gait after stroke is considered one of the most important therapy goals for both patients and therapists, to assure independency and the ability to ambulate in the community. However, over 20% of stroke survivors do not reach independent walking, which necessitates the implementation of more intensive gait rehabilitation strategies. As Hornby et al. correctly state, rehabilitation staff are often too reserved, as they are scared of potential adverse effects, such as cardiovascular events and abnormal kinematic movements strategies.
In this study, Hornby and colleagues questioned if the benefits after high-intensity training in motor recovery outweigh the possible adverse events. In total, 97 chronic stroke patients were randomized in three groups: 1) High-intensity in high variable contexts (speed-dependent and skill-dependent multiple direction treadmill training, overground training and stair climbing at 70-80% of the heart rate reserve); 2) High-intensity with minimal variability (forward stepping treadmill and overground training at 70-80% of heart rate reserve); and 3) Low-intensity in high variable contexts (similar variable contexts as group one, yet performing exercises at 30-40% of heart rate reserve). Primary walking outcomes assessed were self-selected and fasted speed, single-limb stance and step-length asymmetry at self-selected and fasted speed, and six-minute walking test at fasted speed.
After two months of one-hour training sessions, statistically and clinically significant differences were observed between high- versus low-intensity training groups for all walking measures. On all primary walking outcomes, 57% to 80% of participants in the high-intensity group exceeded minimally clinically important differences, while only 9.3% to 31% in the low-intensity group met this threshold. These important benefits for high-intensity training coincided with no significant differences in adverse event rates between groups (p=0.73). However, no clear conclusion could be formulated concerning the contributions of task variability and level of difficulty.
Results of the study of Hornby and colleagues are extremely promising, as they suggest that rehabilitation staff should dare to increase exercise intensity to improve walking function without worrying about reinforcing abnormal locomotor strategies or a higher risk of cardiovascular events. However, future research is still necessary to determine if high-intensity training is also feasible and safe early after stroke. As the majority of neuroplastic changes occur early on during rehabilitation, these patients might benefit even more from this treatment strategy.
Thanks for your comments and enthusiasm regarding this protocol. Our preliminary, feasibility cohort study (Holleran NNR 2014) evaluated this intervention in both subacute (n=12) and chronic (n=10) stroke, revealing substantial gains in all locomotor outcomes. A subsequent randomized trial delineated the potential efficacy of this intervention as compared to conventional interventions. (n=32), although that study did not assess the specific training variables that may contribute to improved outcomes. Dr. Van Criekinge is correct that more work detailing the comparative efficacy of this strategies in patients with subacute stroke is needed in an effort to facilitate adoption of these or similar strategies in the clinical setting.