The global rise in the prevalence of physical inactivity is major public health concern. Lifestyle-related activities, such as stairs walking, has important public health implications and may represent an alternative approach for those who have difficulty adhering to conventional exercise programs. This two-armed, parallel-group, randomized controlled trial (RCT) aims to assess and compare the effects between the descending stair walking (DSW) and ascending stair walking (ASW) on cardiometabolic health markers, cardiopulmonary capacity, body composition and muscular strength.

This RCT will recruit 16 obese inactive and sedentary females will be randomized using permuted block randomization into two arms: intervention arm, DSW and active comparator arm: ASW in a 1:1 allocation ratio. The participants in the DSW and ASW arms will undergo twice a week stair walking intervention session for 8 weeks. The exercise volume will be gradually increased over 8 weeks by increasing the number of repetitions by two every week for both arms. Borg's scale of perceived exertion (RPE) and visual analogue scale (VAS) will be used to assess subjective intensity of stair walking and pain intensity immediately after each repetition. Assessments will be carried out through two time points, pre-intervention assessment (T0) and immediately after completion of the intervention at 8 weeks (T1). During each assessment, the primary outcome to be assessed includes the cardiometabolic health markers and cardiopulmonary capacity, while the secondary outcomes to be assessed are the body composition and muscular strength. Whereas during the intervention, continuous heart rate and gas consumption will be monitored at week 1 (W1), week 4 (W4) and week 8 (W8) to monitor the intensity of the exercise.

1.2 Research Objectives

1.2.1 General Objective (i) The study compares the impact of the 8-week descending stair walking (DSW) and ascending stair walking (ASW) on cardiometabolic health in obese, untrained women.

1.2.2 Specific Objective

To compare the effect of DSW & ASW on:

(i) cardiometabolic health (fasting plasma glucose, lipid profile, renal profile, cardiorespiratory fitness, resting blood pressure, resting energy expenditure, resting heart rate) (ii) body composition (fat mass, lean body mass, waist circumference, hip circumference, thigh circumference) (iii) muscular fitness & functional capacity (back and leg strength & 6-min walking test)

1.3 Research Design This randomized controlled trial (RCT) is a single-centre, two-armed, parallel-group.

1.4 Research Location This RCT is expected to run for 1 year in the Wellness Hub Timur Laut, Klinik Kesihatan Jalan Angsana Pulau Pinang. Wellness Hub Timur Laut is located in the primary healthcare facility of the Ministry of Health and receives approximately 1,000 clients annually for health screening.

1.5 Sampling Method The sampling method used in this study for recruitment of participants is by purposive sampling. Overweight & obese clients of Wellness Hub Jalan Angsana, Klinik Kesihatan Jalan Angsana Pulau Pinang

1.6 Sample Size Calculation The sample size is estimated based on an effect size of 1.91, an α-level of 0.05, and a power (1-β) of 0.08. A priori sample size analysis (G∗Power 3.1; Düsseldorf, Germany) indicated that 6 participants/ group were necessary. Considering a possible dropout rate of 50%, a sample size of 12 participants/ group is anticipated making it a total of 24 participants.

1.7 Data Collection Procedure Permission to conduct the study in Wellness Hub Timur Laut (WHTL), Pulau Pinang, will be sought. Clients will be recruited from WHLA after agreeing to participate in the study.

1.7.1 Data Collection Technique The researcher will interview and assess participants face-to-face at baseline and 8th weeks and the end of the intervention. Participants will be randomly assigned to the stair-walking intervention. At baseline, a background information questionnaire will be used to obtain respondents' sociodemographic characteristics, occupation, health problems and health-related fitness as part of wellness hub health screening. Body composition, metabolic risk factors and selected physical fitness will be assessed before and after the 8th week of intervention.

1.7.2 Daily Energy Balance Monitoring A logbook will be provided for all participants to record daily calorie intake and physical activity. Two weekdays and one-weekend food logs will be retrieved from the logbook, and the total weekly calorie intake and macronutrients will be calculated using Nutritionist Pro software.

1.7.3 Stair Walking Intervention All participants must complete progressive exercise training using stairs in WHLA over 8 weeks, twice a week. The participants in the DSW arm will ride an elevator from level 1 to level 6, eliminating the concentric impact of walking upstairs. Whereas for the ASW arm, participants will ride an elevator from level 6 to level 1 to eliminate the eccentric impact of walking downstairs. The number of stairs from the first to the sixth floor was 120 (five floors, 24 stairs per floor), and the height of each stair was 18 cm. The walking tempo is approximately 1s per step, thus to descend or ascend 120 stairs, it takes about 2 min 30 sec including steps at the landing. The exercise volume will be gradually increased over 8 weeks by increasing the number of repetitions by two repetitions weekly for both arms (first week, 2 repetitions/ session; 8th week, 16 repetitions/ session; 1 repetition,120 stairs).

This protocol assumes that symptoms of muscle damage, such as delayed-onset muscle soreness (DOMS) and prolonged decreases in muscle function, would be minimal after any sessions. It took approximately 5 min to perform one repetition, including the time used for waiting for and riding on an elevator, and the time taken to perform 16 repetitions was approximately 80 min. Lower limb stretching exercises will be included in the workout's general warming-up and cooling-down phases. Over the 16 sessions, each participant will walk up or down 720 floors, thus 17,424 stairs.

Inclusion Criteria:

• Women
• age 18-50-year-old
• BMI 25.0 - 39.9 kg/m2,
• body fat percentage > 30%
• no lower limb orthopaedic injuries
• sedentary lifestyle (regular exercise <1 h per week).

Exclusion Criteria:

• smokers
• taking supplements or medication known to affect REE (such as oral contraceptives),
• severe medical conditions affecting their physical or mental health
• individuals with implanted medical device
• suffer from alcohol or drug abuse and
• trying to conceive/ pregnant or breastfeeding

Female