6-months of flexibility and strengthening exercise

The single-task gait performance measured by the time taken to complete 3-meter timed-up-and-go (TUG) test

The dual-task gait performance measured by the time taken to complete 3-meter timed-up-and-go test with serial subtraction

The composite lower limb strength measured by the time taken to complete 5 repetitions of sitting to standing

The Non-Motor Symptoms Scale is a 30-item rater-based scale to assess a wide range of non-motor symptoms in patients with Parkinson's disease (PD). The NMSS measures the severity and frequency of non-motor symptoms across nine dimensions. The NMSS total score ranges form 0 to 360, with a higher score indicates worse PD non-motor symptoms.

Spatial, gait phase, spatiotemporal and asymmetric walking variables such as gait speed, cadence, stride length, arm swing angle and velocity, and trunk movement angle and velocity will be measured by Mobility Lab system.

The ABC score will be used to measure the participants' perceived level of balance confidence in 16 indoor and outdoor activities. Each activity is rated from 0-100 (0 indicates no confidence and 100 indicates full confidence, total score=1600). The total score is converted into percentage score ranging from 0 to 100%, with a higher ABC score indicating a higher level of balance confidence.

It is a health-related quality-of-life outcome measure that contains 39 self-reported items on eight domains, i.e.: mobility [#1-10], activities of daily living [#11-16], emotional well-being [#17-22], stigma [#23-26], social support [#27-29], cognition [#30-33], communication [#34-36], and body discomfort [#37-39]. The PDQ-39 has been translated into Chinese and validated for local use. Each item is scored on 5-point Likert-type scales ranging from 0 (never), 1 (occasionally), 2 (sometimes), and 3 (often) to 4 (always) based on their perception on the item over the past month. The PDQ-39 total score is 156 and the PDQ-39 summary index is created by summing all eight of the PDQ-39 domains and standardizing the score on a scale of 0-100%. A lower PDQ-39 summary index score reflects a better health-related quality-of-life.

The Pittsburgh Sleep Quality Index is an effective instrument used to measure the quality and patterns of sleep in adults. It differentiates "poor" from "good" sleep quality by measuring seven areas (components): subjective sleep quality, sleep latency, sleep duration, habitual sleep efficiency, sleep disturbances, use of sleeping medications, and daytime dysfunction over the last month. A total score of "5" or greater is indicative of poor sleep quality.

The risk of falling of each group will be determined by the ratio of non-fallers to fallers at treatment completion and 6-month follow-up. A lower risk ratio indicates a lower risk of falling.

The fall rate (times of fall per year per person) of each group at treatment completion and 6-month follow-up will be calculated with the following formula:

Number of fall events X12 / (Number of months spent to assemble fall data X number of subjects)

A lower fall rate indicates a better effect on fall reduction.

The risk of injurious falling of each group at treatment completion and 6-month follow-up will be determined by the ratio of injurious non-fallers to injurious fallers. A lower injurious risk ratio indicates a lower risk of injurious falling.

The injurious fall rate (times of injurious fall per year per person) of each group at treatment completion and 6-month follow-up will be calculated with the following formula:

Number of injurious fall events X12 / (Number of months spent to collect injurious fall data X number of subjects)

A lower injurious fall rate indicates a better effect on injurious fall reduction.