Intervention
instruction-practice, visual or verbal instructions, cognitive and exercise tasks, visual or auditory cues/instructions
ADVERSE EFFECTS, SHOP
The SCET was developed as an arm of a larger project focused on combined training for older adults. The overarching goal of SCET was to improve cognitive function. Participants were instructed to concurrently perform cognitive and exercise tasks, with greater emphasis on cognitive components. It was led by qualified occupational therapists who served as in-person instructors. Throughout the SCET intervention, participants had the opportunity to receive feedback from the in-person instructor. The program consisted of 90–120 min, once a week, for 12 weeks in a group-based setting.Each session was divided into two parts: instruction-practice and training sessions. The instruction-practice session began with a warm-up (10 min), followed by exercise activities (15–20 min). Subsequently, cognitive components were introduced and integrated (20–25 min). The primary aim of this session was to familiarize participants with the simultaneous performance of cognitive and exercise tasks. Following a 10-minute break, the training session commenced. Initially, dual task training was performed for 20–25 min, followed by a short 5-min break, and then another 20–25 min of dual task training. The session concluded with a 5-minute cool-down stretching routine. The primary aim of this session was to make participants implement dual tasks they had learned during the instruction-practice session and actively engaged in dual task training. The time structure of the SCET intervention is illustrated in Fig. 
Time structure of the SCET interventionEach SCET session encompassed cognitive and physical components.The cognitive components consisted of attention, processing speed, memory, calculation, and language. Each session incorporated one or more of these cognitive components. Attention activities involved tasks such as responding to visual or auditory cues/instructions as well as identifying or differentiating colors, shapes, amounts, or sizes of pictures. Processing speed activities required participants to answer questions or follow visual or verbal instructions within a limited time period. Memory activities involved repeating a series of digits or words after seeing or hearing them, performing a series of visual or verbal instructions after seeing or hearing them, and remembering visual images, shapes, or colors. Calculation tasks included answering arithmetic questions presented on the screen or determining the total amount of items taken from the simulated shop or a shopping list. Language tasks encompassed naming fruits, animals, places, or objects in specific environments, as well as constructing logical stories based on a series of given pictures.The physical components of the program consisted of stretching, aerobic exercise, muscle-strengthening exercise, and balance exercise. Participants were encouraged to exercise at moderate intensity, targeting 50–70% of their maximum heart rate. The warm-up and cool-down included upper and lower limb stretching. Aerobic activities involved walking, marching on the spot, and tapping the floor with toes or heels. Balance activities included standing with a narrow base, cross-stepping, and kicking a ball. Muscle-strengthening exercises involved carrying objects and performing upper limb workouts with weighted bottles (filled with water) (e.g., bicep curls, overhead triceps press), as well as lower limb workouts with or without elastic bands (e.g., squats, lunges).During the SCET, attention, processing speed, memory, calculation, and language tasks were performed simultaneously with aerobic, muscle-strengthening, and balance exercises. Stretching exercises were integrated into the warm-up and cool-down portions of the session and were not paired with specific cognitive components. The pairings of cognitive and exercise tasks varied throughout the intervention, with cognitive and physical demands progressively increasing over trials. For instance, the number of words to be recalled or the resistance of the elastic bands used in exercises increased throughout the program. The adaptation of cognitive task difficulty was based on participants’ performance in the previous session. In cases where the cognitive component’s difficulty level was augmented, the difficulty level of the corresponding physical component remained constant. This approach was adopted to prevent potential adverse effects on participants’ performance, ensuring they were not overwhelmed by the task requirements. However, given the group-based training, the adjusted difficulty level of cognitive tasks may not have been perfectly tailored to each participant’s individual capabilities.