Restoration of walking capacity, as reflected by walking speed and walking distance, is a primary goal after stroke. Peak aerobic capacity (peak oxygen consumption [V̇O2peak]) is suggested to be correlated with walking capacity after stroke. Although the strength of this correlation is unclear, physical therapy programs often target walking capacity by means of aerobic training.

Purpose
The purpose of this systematic review was to summarize the available evidence on the correlation between V̇O2peak and walking capacity.

Data Sources
The databases MEDLINE, CINAHL, EMBASE, Cochrane Library, and SPORTDiscus were searched up to May 2014.

Study Selection
Cross-sectional studies reporting correlation coefficients between V̇O2peak and walking capacity in stroke were included, along with longitudinal studies reporting these correlation coefficients at baseline.

Data Extraction
The methodological quality of the studies was assessed using a checklist of 27 items for observational research. Information on study design, stroke severity and recovery, and assessments and outcome of V̇O2peak and walking capacity, as well as the reported correlation coefficients, were extracted.

Data Synthesis
Thirteen studies involving 454 participants were included. Meta-analyses showed combined correlation coefficients (rɱ) for V̇O2peak and walking speed and for V̇O2peak and walking distance of .42 (95% credibility interval=.31, .54) and .52 (95% credibility interval=.42, .62), respectively.

Limitations
The studies included in the present review had small sample sizes and low methodological quality. Clinical and methodological diversity challenged the comparability of the included studies, despite statistical homogeneity. Relevant data of 3 studies could not be retrieved.

Conclusions
The strength of the correlation of V̇O2peak with walking speed was low and moderate for V̇O2peak and walking distance, respectively, indicating that other factors, besides V̇O2peak, determine walking capacity after stroke.