Individualized Cadence Thresholds for Moderate-to-Vigorous Intensity in Obese Taiwanese Young Adults

This study aims to determine the step cadence thresholds for moderate-to-vigorous physical activity (MVPA) in obese young adults. It examines the relationship between body composition and step cadence required to achieve moderate-intensity physical activity (MPA, 3 METs), MPAyoung (4.8 METs), and vigorous physical activity (VPA, 6 METs).

Background: This study examined the relationship between body composition and Moderate-to-Vigorous Physical Activity (MVPA) cadence in obese individuals and establish cadence thresholds for moderate-intensity physical activity (MPA) (3 metabolic equivalents \[METs\]), MPAyoung (4.8 METs), and vigorous physical activity (VPA) (6 METs).

Methods: This study recruited 48 obese young adults who did not regularly engage in exercise. Exclusion criteria included a history of smoking, hypertension, diabetes, cardiovascular or respiratory diseases, neuromuscular or musculoskeletal disorders, or any condition deemed unsuitable for exercise by a physician. The study protocol was approved by the Fu Jen University Institutional Review Board for Human Research (Approval Number: C105137). All participants were fully informed about the study procedures and provided written informed consent prior to participation.

Anthropometrics and Body Composition Measurements Participants arrived at the lab fasted for a minimum of 3 hours, abstained from exercise for 12 hours, avoided caffeine for 6 hours, and refrained from alcohol consumption for 12 hours. Data collection for each subject occurred during the morning hours, as close as possible to awakening from sleep (i.e., from 7:00 AM to 10:00 AM). Height was measured using a digital stadiometer accuracy nearest to ± 0.1 cm (Kongho-Super View, Kong Ho Instruments Co., Ltd., New Taipei, Taiwan). Body composition was assessed using bioelectrical impedance analysis (BIA) with the InBody 720 device (Biospace Co., Ltd., Seoul, South Korea). Skin resistance was measured through an eight-point tactile-electrode system at different frequencies (1 kHz, 5 kHz, 50 kHz, 250 kHz, 500 kHz, 1 MHz). Lean body mass and fat mass were determined from the impedance values using the manufacturer's regression equations, based on the principle that different tissues have varying water content and, consequently, different electrical conductivity 30. The components used in further analysis included weight, body mass index (BMI), body fat mass (BFM), body fat percentage (FAT), visceral fat area (VFA), and skeletal muscle mass (SMM).

Incremental Submaximal Exercise Testing Protocol Participants were instructed to refrain from vigorous exercise, smoking, and the consumption of caffeine-containing foods and beverages for 24 hours prior to the experiment. During the test, each participant was equipped with a gas analyzer (MetaMax 3B, Cortex, Leipzig, Germany) and a heart rate monitor (Polar H10, Electro Oy, Kempele, Finland). The protocol began with a 10-minute seated rest period to measure resting oxygen consumption. Subsequently, participants completed an incremental submaximal treadmill walking test consisting of five stages, with speeds set at 3.2, 4.0, 4.8, 5.6, and 6.4 km/h. Each stage lasted 5 minutes, and participants were instructed to maintain a natural walking pattern throughout the test. Oxygen consumption was continuously recorded during the exercise phases using the gas analyzer, while the total step count for each stage was captured using a video camera.

Eligibility Criteria:
Inclusion Criteria:

* Adults aged 19-21 years
* BMI classified as obese (≥27 kg/m²)
* Able to walk on a treadmill without assistance

Exclusion Criteria:

* Presence of metabolic, cardiovascular, or musculoskeletal disorders
* History of bariatric surgery
* Current participation in structured exercise program