PregFit Adventure: Strengthening Mothers-to-Be

1. Design.

This will be a randomized clinical trial (RCT) with two groups, an experimental or intervention group and a control group. 2. Population, criteria, sample, calculation.

The study population will be low-risk pregnant women.

Inclusion criteria:

• Pregnant women at low obstetric risk and with no musculoskeletal or health problems affecting their physical condition, ability to exercise or participate in the exergame activities.
• Read the information sheet and sign the informed consent form to agree to take part in the study.
• >18 years of age
• Spanish comprehension and communication skills
• Able to perform physical activity related to the use of the device for at least 30 minutes, 2-3 times a week, for at least 8 weeks

Exclusion criteria:

• Failure to meet any of the inclusion criteria
• Giving birth during the procedure and at least 8 weeks of device use have not elapsed.

Assignment: All women receiving maternal education from all participating health centers will be randomized to ensure that there is no sample contamination and their relevance to the intervention or control group will be established according to randomization.

Sample size calculation: It was estimated that the number of participants should be at least 15% for this pilot study of what would be a future intervention project. Using self-perceived physical fitness as the dependent variable, and in validation studies having had samples of around 160 women (Romero-Gallardo et al., 2020), at least 24 women will be needed in the single intervention group for this pilot study. Similarly, at least 24 women in the control group are needed for comparison. It is estimated that 20% of women may drop out of the intervention before the minimum 8 weeks, thus establishing a sample size of at least 30 women to recruit. Using similar studies (Tuan et al., 2024) as a reference, we will try to reach the ideal sample size of 42 healthy pregnant women who complete the intervention and at least 42 for the control group who receive routine pregnancy follow-up EpS and antenatal classes. 3. Description of the intervention.

• Intervention Group: The program consists of using the device, a minimum of 30 minutes per session two to three times per week and not exceeding ≥3 hours, for at least 8 weeks up to a maximum of 3 months or until the onset of discomfort disabling physical activity, with the minimum time for intervention being at least 8 weeks. Exercise based on exergames will be performed including at least 10 minutes of warm-up and 10 minutes of cool-down, and under the supervision of a licensed health professional.

The training program will focus on strength and functional movements. It requires a Nintendo Switch console, a Ring-Con (a Pilates ring that the user holds or ring holder), wireless Joy-Con controllers (the right Joy-Con, connected to the Ring-Con; and the left Joy-Con, attached to the strap around the player's thigh) and a screen. In adventure mode, women will move through the game by performing physical activities such as jogging or doing squats. To minimize risk, knee-assist mode will be used, which makes the game more accessible. Activating knee assist mode provides support when women perform exercises that require walking, kneeling or squatting, making these activities easier for pregnant women, increasing the fitness benefits of the game. In battle mode women will perform aerobic activities, strength training and yoga exercises that involve the whole body to advance in the game. Women will receive in-game coin rewards, character customization and level progression based on exercise volume, which encourages improvement of their skills. As an example, with the assisted knee mode, women will have to squeeze and stretch the titular ring working muscles such as the trapezius, triceps, pectoralis major and minor and abdominal muscles. In addition, to go about defeating the monsters they will have to do shoulder abduction and adduction exercises, internal and external rotation of the shoulders and flexion of the elbow as shown in the images of the orientation trailer, provided to women and available in this memory.

@Control Group: Low-risk pregnant women who have normal pregnancy follow-up with Health Education received in childbirth preparation classes and maternal education received in routine pregnancy care by primary and specialized care midwives.

Masking: Unique (Results Evaluator).

Description of masking: Due to the design of the study and the nature of the interventions, it is impossible to mask staff and participants at the care centers. The evaluators, who measure the outcomes, and the interpreter, who analyzes the data, will be masked in this study.

Place: It will take place in a health center, which is part of the ecosystem of the Andalusian Health Service.