The purpose of this study is to find out the effectiveness of high intensity exercise (HIE) early after stroke, this study is hoping to recruit 36 participants in total and will be analysing pre- and post- outcomes of patients in a high intensity exercise intervention, as compared to a lower intensity exercise programme. Participants will be randomly assigned to either the high or low intensity exercise programme, and receiving the assigned intervention for 2 weeks. Both groups in the study will be subjected to same post-stroke functional and locomotion training as part of their physiotherapy intervention, but at different intensities. This ranges from body weight supported training, to treadmill training, to robotics walking and functional training (including overground walking/ stepping and cardiorespiratory fitness training), as per conventional post-stroke rehabilitation. The high intensity experimental group will undergo high-intensity exercise (HIE) training defined by 60-84% (heart rate reserve), or RPE (rate of perceived exertion) Borg 14-16, while the low intensity control group will undergo lower intensity training defined by HRR 59% and below, or RPE Borg 13 and below. Measurements will be taken from assessments at pre- and post- interventions will be analysed and compared between the two groups to find out which intervention programme is more effective for patients early after stroke. These assessments include functional outcomes such as walking speed, chair rise test and also a neurobiological measure looking at levels of cortical activation called the functional near infrared spectroscopy (fNIRS) which is measured via a non-invasive cap that you wear on. The participants will be expected to don on the fNIRS device for a total of 15-30 minutes, and an average of 3 sets of 30-seconds measurements during their walking assessment will be taken.