Participants will undergo four weekly supervised VR-based training sessions, each lasting approximately 35 minutes, over four weeks. Each session includes:

1. VR Warm-Up: Activities adapted from NVIDIA VR Fun House on SteamVR, involving repetitive movements through mini-games like throwing objects, archery, and sword handling.
2. Aerobic and Balance Exercises: Walking in place within a virtual natural environment, incorporating stretching steps and one-leg balance tasks.
3. Lower-Body Training: VR-based exercises such as Balloon Game for hip flexibility (popping balloons with foot movements), Cave Game for squatting motions, and sit-to-stand activities.
4. Upper-Body Training: VR exercises involving racket-based ball hitting and reaching activities at varied distances.

In this condition, instead of motivational stimuli, participants received neutral information regarding the activity (e.g., "This exercise is good for your legs ").

Participants will engage in four individual training sessions, supervised by a trainer, scheduled once per week for a total duration of four weeks. Each session will last approximately 35 minutes and include: 5 minutes of warm-up and stretching, 10 minutes of aerobic and balance exercises (walking in place, heel raises, knee lifts, leg curls), 10 minutes of lower-body exercises (squats), and 10 minutes of upper-body exercises (shoulder abduction 180°, shoulder flexion 180°, shoulder external rotation 90°, bending 35°, trunk extensions 80°).

Participants received motivational messages from a real coach designed to enhance the three psychological needs outlined in Self-Determination Theory: competence, autonomy, and relatedness.

Participants will engage in four individual training sessions, supervised by a trainer, scheduled once per week for a total duration of four weeks. Each session will last approximately 35 minutes and include: 5 minutes of warm-up and stretching, 10 minutes of aerobic and balance exercises (walking in place, heel raises, knee lifts, leg curls), 10 minutes of lower-body exercises (squats), and 10 minutes of upper-body exercises (shoulder abduction 180°, shoulder flexion 180°, shoulder external rotation 90°, bending 35°, trunk extensions 80°). In this condition, instead of motivational stimuli, participants received neutral information regarding the activity (e.g., "This exercise is good for your legs ").

Mental health was assessed using the 12-Item Short Form Survey (SF-12), which comprises 12 items. Raw scores are transformed into T-scores, with higher scores indicating better mental health.

Hearth rate variability was measure through the smartwatch EMPATICA EmbracePlus.

Galvanic conductance was measure through the smartwatch EMPATICA EmbracePlus.

The Godin-Shephard Leisure-Time Physical Activity Questionnaire. The GSLTPAQ comprises three items, each representing a different intensity of exercise: strenuous (e.g., running), moderate (e.g., fast walking), and mild (e.g., yoga). Participants report the number of times per week they engage in 20 minutes of strenuous, moderate, and mild exercise during their free time. To calculate the Leisure Score Index (LSI), the weekly duration of each activity type is multiplied by its respective Metabolic Equivalent Task (MET) value: 3 for mild, 5 for moderate, and 9 for strenuous. Larger values indicate higher levels of engagement in physical activity.

The Psychological Need Satisfaction in Exercise Scale (PNSE) was used to assess SDT basic psychological needs. The PNSE consists of 18 items, rated on a 6-point Likert scale (from 1 ="false" to 6 = "true"). Larger values indicate higher satisfaction of basic psychological needs.

The Behavioural Regulations in Exercise Questionnaire (BREQ-3) was use to assess motivation for physical activity as poised by the Self-Determination Theory. It consists of 18 items rated on a five-point Likert scale, ranging from 0 ("not true for me") to 4 ("very true for me").

Physical health was assessed using the 12-Item Short Form Survey (SF-12), which comprises 12 items. Raw scores are transformed into T-scores, with higher scores indicating better physical health.

Mental health was assessed using the 12-Item Short Form Survey (SF-12), which comprises 12 items. Raw scores are transformed into T-scores, with higher scores indicating better mental health.

Hearth rate variability was measure through the smartwatch EMPATICA EmbracePlus.

Galvanic conductance was measure through the smartwatch EMPATICA EmbracePlus.

The Godin-Shephard Leisure-Time Physical Activity Questionnaire. The GSLTPAQ comprises three items, each representing a different intensity of exercise: strenuous (e.g., running), moderate (e.g., fast walking), and mild (e.g., yoga). Participants report the number of times per week they engage in 20 minutes of strenuous, moderate, and mild exercise during their free time. To calculate the Leisure Score Index (LSI), the weekly duration of each activity type is multiplied by its respective Metabolic Equivalent Task (MET) value: 3 for mild, 5 for moderate, and 9 for strenuous. Larger values indicate higher levels of engagement in physical activity.

The Psychological Need Satisfaction in Exercise Scale (PNSE) was used to assess SDT basic psychological needs. The PNSE consists of 18 items, rated on a 6-point Likert scale (from 1 ="false" to 6 = "true"). Larger values indicate higher satisfaction of basic psychological needs.

The Behavioural Regulations in Exercise Questionnaire (BREQ-3) was use to assess motivation for physical activity as poised by the Self-Determination Theory. It consists of 18 items rated on a five-point Likert scale, ranging from 0 ("not true for me") to 4 ("very true for me").

Physical health was assessed using the 12-Item Short Form Survey (SF-12), which comprises 12 items. Raw scores are transformed into T-scores, with higher scores indicating better physical health.

Mental health was assessed using the 12-Item Short Form Survey (SF-12), which comprises 12 items. Raw scores are transformed into T-scores, with higher scores indicating better mental health.

Hearth rate variability was measure through the smartwatch EMPATICA EmbracePlus.

Galvanic conductance was measure through the smartwatch EMPATICA EmbracePlus.

The Godin-Shephard Leisure-Time Physical Activity Questionnaire. The GSLTPAQ comprises three items, each representing a different intensity of exercise: strenuous (e.g., running), moderate (e.g., fast walking), and mild (e.g., yoga). Participants report the number of times per week they engage in 20 minutes of strenuous, moderate, and mild exercise during their free time. To calculate the Leisure Score Index (LSI), the weekly duration of each activity type is multiplied by its respective Metabolic Equivalent Task (MET) value: 3 for mild, 5 for moderate, and 9 for strenuous. Larger values indicate higher levels of engagement in physical activity.

The Psychological Need Satisfaction in Exercise Scale (PNSE) was used to assess SDT basic psychological needs. The PNSE consists of 18 items, rated on a 6-point Likert scale (from 1 ="false" to 6 = "true"). Larger values indicate higher satisfaction of basic psychological needs.

The Behavioural Regulations in Exercise Questionnaire (BREQ-3) was use to assess motivation for physical activity as poised by the Self-Determination Theory. It consists of 18 items rated on a five-point Likert scale, ranging from 0 ("not true for me") to 4 ("very true for me").

Physical health was assessed using the 12-Item Short Form Survey (SF-12), which comprises 12 items. Raw scores are transformed into T-scores, with higher scores indicating better physical health.

Mental health was assessed using the 12-Item Short Form Survey (SF-12), which comprises 12 items. Raw scores are transformed into T-scores, with higher scores indicating better mental health.

Galvanic conductance was measure through the smartwatch EMPATICA EmbracePlus.

Hearth rate variability was measure through the smartwatch EMPATICA EmbracePlus.

The Self-Efficacy for Exercise Scale (SEE) is a self-report questionnaire composed of nine items for the assessment of self-efficacy for exercise, specifically designed for older adults. Each item is rated on an 11-point scale (from 0 = "Not confident" to 10 = "Very confident"). Scores ranges from a minimum of 0 to a maximum of 90. Larger values reflects higher degree of confidence that an elder has in engaging in exercise in the presence of specific barriers.

Virtual Reality Symptoms Questionnaire. This self-report questionnaire comprises 13 items divided into two dimensions: physical symptoms (8 items) and eye-related symptoms (5 items). Each item is rated on a 7-point Likert scale (ranging from 0 = "none" to 6 = "severe"). Scores for physical symptoms range from 0 to 48. Higher scores indicate greater discomfort.

Virtual Reality Symptoms Questionnaire. This self-report questionnaire comprises 13 items divided into two dimensions: physical symptoms (8 items) and eye-related symptoms (5 items). Each item is rated on a 7-point Likert scale (ranging from 0 = "none" to 6 = "severe"). Scores for eye-related symptoms range from 0 to 40. Higher scores indicate greater discomfort.

The Subjective Vitality/Depletion Scale was use to assess well-being. This self-report questionnaire is composed of six items rated on a 7-point Likert scale (from 1 = "Not at all true" to 7 = "Very true"). Higher scores are indicative of higher well-being.

The Self-Efficacy for Exercise Scale (SEE) is a self-report questionnaire composed of nine items for the assessment of self-efficacy for exercise, specifically designed for older adults. Each item is rated on an 11-point scale (from 0 = "Not confident" to 10 = "Very confident"). Scores ranges from a minimum of 0 to a maximum of 90. Larger values reflects higher degree of confidence that an elder has in engaging in exercise in the presence of specific barriers.

Virtual Reality Symptoms Questionnaire. This self-report questionnaire comprises 13 items divided into two dimensions: physical symptoms (8 items) and eye-related symptoms (5 items). Each item is rated on a 7-point Likert scale (ranging from 0 = "none" to 6 = "severe"). Scores for physical symptoms range from 0 to 48. Higher scores indicate greater discomfort.

Virtual Reality Symptoms Questionnaire. This self-report questionnaire comprises 13 items divided into two dimensions: physical symptoms (8 items) and eye-related symptoms (5 items). Each item is rated on a 7-point Likert scale (ranging from 0 = "none" to 6 = "severe"). Scores for eye-related symptoms range from 0 to 40. Higher scores indicate greater discomfort.

The Subjective Vitality/Depletion Scale was use to assess well-being. This self-report questionnaire is composed of six items rated on a 7-point Likert scale (from 1 = "Not at all true" to 7 = "Very true"). Higher scores are indicative of higher well-being.

The Self-Efficacy for Exercise Scale (SEE) is a self-report questionnaire composed of nine items for the assessment of self-efficacy for exercise, specifically designed for older adults. Each item is rated on an 11-point scale (from 0 = "Not confident" to 10 = "Very confident"). Scores ranges from a minimum of 0 to a maximum of 90. Larger values reflects higher degree of confidence that an elder has in engaging in exercise in the presence of specific barriers.

Virtual Reality Symptoms Questionnaire. This self-report questionnaire comprises 13 items divided into two dimensions: physical symptoms (8 items) and eye-related symptoms (5 items). Each item is rated on a 7-point Likert scale (ranging from 0 = "none" to 6 = "severe"). Scores for physical symptoms range from 0 to 48. Higher scores indicate greater discomfort.

Virtual Reality Symptoms Questionnaire. This self-report questionnaire comprises 13 items divided into two dimensions: physical symptoms (8 items) and eye-related symptoms (5 items). Each item is rated on a 7-point Likert scale (ranging from 0 = "none" to 6 = "severe"). Scores for eye-related symptoms range from 0 to 40. Higher scores indicate greater discomfort.

The Subjective Vitality/Depletion Scale was use to assess well-being. This self-report questionnaire is composed of six items rated on a 7-point Likert scale (from 1 = "Not at all true" to 7 = "Very true"). Higher scores are indicative of higher well-being.

The Self-Efficacy for Exercise Scale (SEE) is a self-report questionnaire composed of nine items for the assessment of self-efficacy for exercise, specifically designed for older adults. Each item is rated on an 11-point scale (from 0 = "Not confident" to 10 = "Very confident"). Scores ranges from a minimum of 0 to a maximum of 90. Larger values reflects higher degree of confidence that an elder has in engaging in exercise in the presence of specific barriers.

Virtual Reality Symptoms Questionnaire. This self-report questionnaire comprises 13 items divided into two dimensions: physical symptoms (8 items) and eye-related symptoms (5 items). Each item is rated on a 7-point Likert scale (ranging from 0 = "none" to 6 = "severe"). Scores for physical symptoms range from 0 to 48. Higher scores indicate greater discomfort.

Virtual Reality Symptoms Questionnaire. This self-report questionnaire comprises 13 items divided into two dimensions: physical symptoms (8 items) and eye-related symptoms (5 items). Each item is rated on a 7-point Likert scale (ranging from 0 = "none" to 6 = "severe"). Scores for eye-related symptoms range from 0 to 40. Higher scores indicate greater discomfort.