Background: The majority of stroke survivors regain walking ability. However, the ability to adapt gait patterns to meet environmental demands remains impaired in a majority of people in the chronic phase after stroke. This impaired gait adaptability has a profound impact on activities of daily living and quality of life. Treatment targeting gait adaptability is therefore critical for safe and independent community ambulation in people with stroke. Augmented or virtual reality in rehabilitation programs can be used to train gait adaptability in a controlled situation. A few studies have evaluated gait adaptability training in people with stroke. Although results were promising, these studies did not include an adaptability-related outcome measure, or were limited to uncontrolled or small-scaled pilot studies. Moreover, it is unknown if beneficial training effects can be fostered for 1 year after completion of a training program. We evaluate the short-term effects of a 5-week gait adaptability training in an adequately powered, waiting-list controlled clinical trial [ref naar clin trial nummer]. In the current study, we focus on the retention of potentially beneficial effects of this 5 week gait adaptability training program. We will evaluate if short-term effects of gait adaptability training can be retained through single training sessions to boost performance, or by an home exercise program. We hypothesize that booster sessions and home-based exercise will both yield better retention of training effects at 1 year follow-up as compared to the control arm without an experimental intervention.

Objective: The primary objective of this study is to test the hypothesis that retention of training-induced gains in gait adaptability can be fostered by providing booster sessions or by prescribing home-based training.

Study design: Explorative randomized study, comparing the effect of 3 1-hr booster training sessions against home-based exercise against no intervention on gait adaptability performance 1 year after completion of a 5-week gait adaptability training program.

Study population: Stroke patients in the chronic phase after stroke, who completed the 5-week gait adaptability training using the C-Mill and agreed to continue in this follow-up study. We expect this to be 50-75 participants.

Inclusion Criteria:

• > 6 months after first unilateral supratentorial stroke (chronic phase)
• Able to walk at least 10 minutes independently
• Initial involvement of the lower extremity after stroke.
• Having completed (minimal 8/10 training sessions) the 5 week gait adaptability training program using the C-Mill

Exclusion Criteria:

• Any other neurological or musculoskeletal disease affecting gait or balance (e.g. Parkinson's disease, knee osteoarthritis)
• Contractures or spasticity requiring other treatment (e.g. botulinum toxin treatment) within the duration of the training period.
• Severe cognitive or visuo-spatial impairments limiting comprehension of instructions or correct perception of the environments