Test reliability of the Brief-BESTest in people with chronic obstructive pulmonary disease

All participants will be asked to attend two assessment sessions (in addition to their routine assessment for pulmonary rehabilitation program). - On the first assessment day, participant will be assessed by spirometry, the six-minute walk test (6MWT) and Brief-BESTest (by assessor 1). The duration of this assessment will last for 30-45 minutes. - On the second assessment day, participant will be assessed by 6WMT (if necessary) and two Brief-BESTests which will be performed by two different assessors (by assessor 1 and assessor 2). The two assessors will perform an independent balance assessment with 15 minutes rest between tests (i.e. the participant will be assessed by two different assessors on the second assessment day with 15 minutes rest in between). The testing sequence of the assessors will be randomly assigned. All assessors are experienced therapists who are specifically trained in administering the Brief-BESTest. This assessment section will last for about 30-45minutes. There will be a maximum of 7 days apart between the two assessment sessions. Outcome Measures Exercise capacity will be measured by the six-minute walk test (6MWT). Two 6MWTs will be performed and the distance walked from the better 6MWT will be used for analysis. Fear of Falling: This will be measured by the Fall Efficacy Scale International (FES-I). The FES-I is a self-reported questionnaire providing information on level of concern about falls for a range of activities of daily living. Balance performance: This will be measured by the brief version of the Balance Evaluation Systems Test (BESTest). The brief-BESTest is a comprehensive balance assessment tool which designed to assess six different aspects contributing to postural control in standing and walking. The test will take about 5-8 minutes to complete. Components of the test: 1. hip lateral strength - asking participant to lift the leg sideway while keeping the trunk vertical for at least 10 seconds. Both sides will be tested. 2. functional reach test - asking the participant to reach forward as much as possible without lifting the heels. The maximum forward reaching distance will be measured. 3. single leg standing - asking participant to stand on one leg for as long as possible (a max of 20 seconds), both sides will be tested 4. compensatory lateral stepping correction - leaning into the hands of the assessor laterally, The assessor will release hands suddenly to assess compensatory skill of the participant. 5. standing on a foam with eyes closed - testing the ability of the participant to stand on a foam (AIREX balance pad) with eyes closed for a max of 30 seconds 6. timed up and go test - timing the time requires to complete the test. Each item is scored on a 3 points scale (0 representing severe impairment and 3 representing no balance impairment) with a total score of 24 points. With items include both a right and left component, the side will score less will be included in the final score. equipment require for the Brief-BESTest - stop watch - AIREX balance pad - a chair and a walk track for timed up and go - a tape measure or ruler for functional reach test Lung Function: Spirometry will be measured at baseline using standard techniques. Lung function data will be used to define disease severity.