Balance impairment increases the risk of falling and is associated with a fear of falling and immobility. Balance impairment can ultimately affect the morbidity of cardiovascular disease, cognitive impairment, and mortality, especially in an older population. Among the multiple types of exercise, balance training is the most effective in preventing falls. This study aims to investigate white matter plasticity in healthy elderly population, based on stepwise balance training. Healthy elderly participants will undergo four weeks of balance training. The investigators will analyze longitudinal changes in the microstructural integrity of the white matter tracts pre- and post-training.

Balance is an essential element of daily living. Balance impairment increases the risk of falling and is associated with a fear of falling and immobility. Balance impairment can ultimately affect the morbidity of cardiovascular disease, cognitive impairment, and mortality, especially in an older population. Among the multiple types of exercise, balance training is the most effective in preventing falls. Specific structures of the brain are highly associated with balance, and the integration of functions from these structures maintains balance function.

Training-induced behavioral changes accompany white matter plasticity. White matter plasticity by practicing expert skills has been of particular interest because characteristic changes in white matter are expected to occur through repetitive and intensive motor skill training. Training-induced white matter plasticity regarding balance is less understood in the healthy adult population. Previous neuroimaging studies have focused on elucidating the cross-sectional associations between balance function and disease-specific characteristics in various clinical populations, such as patients with stroke, traumatic brain injury, Parkinson's disease, and other neurodegenerative diseases.

Developing neuroimaging biomarkers is essential to provide individualized training or rehabilitation intervention and to evaluate its efficacy. Diffusion tensor imaging is a sensitive neuroimaging tool to detect myelin change quantitatively in human white matter in vivo. DTI is used to measure water molecules' diffusion anisotropy, called fractional anisotropy (FA).

This study will explore white matter plasticity in a healthy elderly population which practices stepwise balance training for 4 weeks. The investigators adopt a longitudinal design to contrast the neuroplastic changes in white matter tracts linked to balance function. The investigators hypothesize that balance training would change the microstructural integrity of white matter tracts associated with balance improvement.

Inclusion Criteria:

• Mini-mental state examination ≥ 26
• Independent outdoor ambulator

Exclusion Criteria:

• Men/women with any metal implants in their body
• A prior history of psychopathology or a neurological disorders
• A prior history of osteoporosis, advanced osteoarthritis (K-L grade >=3), surgical history of hip or knee arthroplasty
• If any structural abnormalities are detected on their scan