Participants in the intervention group will engage in a dual-task training program, in which resistance training will be incorporated with cognitive tasks (2 sessions per week for 10 weeks consecutively). The training sessions will take place in an academic institution under the guidance and supervision from the members of research team.

Subjects in the control group will perform the resistance exercises only (2 sessions per week for 10 weeks consecutively) without receiving any cognitive training. The training sessions will take place in an academic institution under the guidance and supervision from the members of our research team.

Participants in the intervention group will engage in a dual-task training program, in which resistance training will be incorporated with cognitive tasks.

- Resistance training: Participants will be instructed to perform the following exercises with proper form: (1) squat to chair, (2) seated unilateral hip flexion, (3) seated unilateral knee extension, (4) standing unilateral knee flexion and (5) bilateral calf raise. The lower limb exercises will be followed by four upper limb exercises: (6) seated elbow flexion, (7) twisting a towel, (8) seated horizontal opening of arms and elbow, (9) seated diagonal opening of arm and elbow.

- Cognitive task: Subjects will be asked to perform a verbal fluency task or mental arithmetic tasks simultaneously with the resistance training exercises.

The primary outcomes will be feasibility and acceptability of the dual task training program. Feasibility will be evaluated through recruitment and compliance rates of the program. Recruitment rate will be defined as the total number of participants recruited out of the total number of participants screened. Treatment compliance will be defined as the proportion of scheduled sessions attended in each group. Acceptability will be assessed by a six-question post-program questionnaire based on the barriers to engaging in physical activity. Questions relating to perceived importance and satisfaction with the program, any discomfort felt during training, difficulty of the exercises, appropriateness of duration and usefulness on daily activity will be asked to rate from a 5-point Likert scale from 'Strongly disagree' to 'Strongly agree', and be collected at the end of the intervention.

Measured by the Tilburg frailty indicator (TFI).

• There are 15 items in total, with a score of 0 or 1 on each item. The total score ranges from 0 to 15 points. A higher score mean a worse outcome (Higher frailty level).
• A total score of >/=5 has a validity of 0.86 to determine the frailty status of the community-dwelling older Chinese population (Dong et al., 2017).

Measured by Fried Frailty Phenotype (FFP).

• It consists of 5 components in assessing the severity of frailty, including weight loss, weakness, exhaustion, slowness and low physical activity, with a score of 0 or 1 for each component.
• The total score ranges from 0 to 5 points. A higher score mean a worse outcome. The frailty status is categorized into robust (0), pre-frail (1-2), and frail (3-5).

Measured by Short Physical Performance Battery (SPPB).

• The SPPB is an assessment tool for participants' physical function and can be used to show the physical frailty.
• It includes 3 components: standing balance, 4-m gait speed, and five-repetition sit-to-stand motion. Each component has a score of 0-4. The total score ranges from 0 to 12 points. A higher score mean a worse outcome.
• A total score of <9 is regarded as frail.

Measured by Hong Kong version Montreal Cognitive Assessment (HK-MoCA).

• The score ranges from 0 to 30 points. A higher score indicates better cognitive function.
• A score of 25 or below may indicate the presence of mild cognitive impairment.