Background: Insufficient physical activity due to social distancing and suppressed outdoor activities increases vulnerability to diseases like cardiovascular diseases, sarcopenia, and severe COVID-19. While bodyweight exercises, such as squats, effectively boost physical activity, incorrect postures risk abnormal muscle activation joint strain, leading to ineffective sessions or even injuries. Avoiding incorrect postures is challenging for novices without expert guidance. Existing solutions for remote coaching and computer-assisted posture correction often prove costly or inefficient. Objective: This study aimed to use deep neural networks to develop a personal workout assistant that offers feedback on squat postures using only mobile devices—smartphones and tablets. Deep learning mimicked experts’ visual assessments of proper exercise postures. The effectiveness of the mobile app was evaluated by comparing it with exercise videos, a popular at-home workout choice. Methods: Twenty participants were recruited without squat exercise experience and divided into an experimental group (EXP) with 10 individuals aged 21.90 (SD 2.18) years and a mean BMI of 20.75 (SD 2.11) and a control group (CTL) with 10 individuals aged 22.60 (SD 1.95) years and a mean BMI of 18.72 (SD 1.23) using randomized controlled trials. A data set with over 20,000 squat videos annotated by experts was created and a deep learning model was trained using pose estimation and video classification to analyze the workout postures. Subsequently, a mobile workout assistant app, Home Alone Exercise, was developed, and a 2-week interventional study, in which the EXP used the app while the CTL only followed workout videos, showed how the app helps people improve squat exercise. Results: The EXP significantly improved their squat postures evaluated by the app after 2 weeks (Pre: 0.20 vs Mid: 4.20 vs Post: 8.00, P=.001), whereas the CTL (without the app) showed no significant change in squat posture (Pre: 0.70 vs Mid: 1.30 vs Post: 3.80, P=.13). Significant differences were observed in the left (Pre: 75.06 vs Mid: 76.24 vs Post: 63.13, P=.02) and right (Pre: 71.99 vs Mid: 76.68 vs Post: 62.82, P=.03) knee joint angles in the EXP before and after exercise, with no significant effect found for the CTL in the left (Pre: 73.27 vs Mid: 74.05 vs Post: 70.70, P=.68) and right (Pre: 70.82 vs Mid: 74.02 vs Post: 70.23, P=.61) knee joint angles. Conclusions: EXP participants trained with the app experienced faster improvement and learned more nuanced details of the squat exercise. The proposed mobile app, offering cost-effective self-discovery feedback, effectively taught users about squat exercises without expensive in-person trainer sessions. Trial Registration: Clinical Research Information Service KCT0008178 (retrospectively registered); https://cris.nih.go.kr/cris/search/detailSearch.do/24006

Objective: This study addresses declining physical fitness among Korean firefighters due to a low exercise participation rate caused by the absence of exercise instructors. The research explores Virtual Mate (VM), a Kinect-based mixed reality device, as a potential solution, but its capacity to replace training instructors in enhancing physical fitness remains uncertain. Methods: Twenty Korean male firefighters were divided into two groups: the exercise group received an 8-week intervention using VM, while the control group maintained regular physical activity. Cardiopulmonary function and muscle function were measured. Results: After 8 weeks, the exercise group demonstrated a significant improvement in VO_2peak. Furthermore, there were notable enhancements in the strength and endurance of most knee, shoulder, and trunk flexors and extensors. Conclusions: Integrating VM into an exercise program can effectively improve cardiorespiratory and muscular function in Korean firefighters.

Objective: The Candidate Physical Capability Test (CPAT) has been used in many countries to assess the fitness levels of firefighters, but it requires a special facility with a space of at least 900 square m² and expensive equipment. Because it can be difficult to have both money and space at smaller gas stations, we have developed the Korean Firefighter Performance Battery (KFPB). Methods: To verify the validity and reliability of the developed KFPB, this study consists of three parts, a validation test, reliability test, and evaluation criterion. Results: As a result of the analysis, the KFPB met all of the criteria as a valid evaluation. Furthermore, the KFPB seems to compensate for the shortcomings of CPAT. Conclusions: In locations where the CPAT is difficult to administer, the KFPB is expected to be used as a firefighting job–related physical fitness evaluation.

OBJECTIVES This study aims to compare and analyze the effects of different exercise instruction methods, with high-intensity aerobic exercise using smartphone-based applications versus in-person trainers, on the aerobic capacity and exercise-related psychological indicators (achievement, satisfaction, and immersion) of university students, thereby verifying their actual effectiveness.METHODS This study randomly assigned 27 male college students to an application-based exercise group (AEG, n=9), a trainer-led face-to-face exercise group (HEG, n=9), and a control group (CG, n=9). Both exercise groups engaged in aerobic exercise three times per week for 30 minutes each session, at an intensity of 70–85% of maximum heart rate, for a period of 8 weeks. Measurement indicators included body composition, exercise stress testing, and the Cooper 1.5-mile run test to measure VO2max. Furthermore, a survey was conducted to assess exercise achievement, satisfaction, and exercise persistence. The statistical analysis employed a variety of methods, including paired t-tests, independent t-tests, one-way analysis of variance (ANOVA), and 2×3 repeated measures ANOVA.RESULTS First, no significant differences in body composition were observed between groups. Second, a significant interaction effect between group and time was observed for VO2max in the HEG group (p = 0.022). Third, the survey results showed that the HEG group achieved significantly higher scores than the AEG group in the items “perceived improvement in physical ability,” “improved confidence and mental state,” and “adherence to exercise plans.” However, the AEG group also demonstrated high scores, with an average of above 3.68 in exercise achievement, satisfaction, and participation.CONCLUSIONS Application-based exercise yielded relatively high scores in exercise achievement, satisfaction, and immersion despite limited improvements in aerobic capacity, suggesting a partial disconnect between psychological indicators and aerobic fitness. In light of the persistent escalation in obesity rates, the utilization of exercise applications emerges as a prospective strategy to improve physical activity levels.

Ji-Been Kim, Min-Geon Je, Chae-Been Kim, Jung-Jun Park, Hyun-Joo Kang, Wook Song, Chung-Gun Lee, Yeon-Soon Ahn, Han-Joon Lee, Dong-Il Seo. KJSM 2024;42:23-30. https://doi.org/10.5763/kjsm.2024.42.1.23

PURPOSE: Pooled reference data for Korean adults are limited, and Western norms may not be applicable because of ethnic differences. This study aimed to describe sex- and age-specific distributions of knee isokinetic peak torque normalized to body weight in healthy Korean adults.METHODS: Following PRISMA guidelines, PubMed, Web of Science, Google Scholar, RISS, and KISS were searched for articles published between 1990 and 2023 using combinations of the terms “isokinetic,” “muscle strength,” “muscle function,” and “Korean.” Studies were eligible if they assessed knee isokinetic strength in healthy Korean adults using Cybex or HUMAC NORM. Weighted means and 95% confidence intervals (CI) for peak torque at 60˚/s (% body weight [BW]) were calculated based on sample size.RESULTS: Thirteen studies (n=426; 245 men, 181 women) were included. In men, left knee extensor peak torque decreased from 267.5 %BW (95% CI 260.7–274.3) in those aged 20–29 years to 143.3 %BW (130.6–155.9) in those aged >60 years. In women, left knee extensor peak torque declined from 227.3 %BW (211.6–242.9) in adults aged 20–29 years to 86.7 %BW (78.7–94.6) in those aged >60 years. Flexor strength showed similar age-related declines, and men consistently exhibited higher peak torque than women.CONCLUSIONS: This study provides the first combined descriptive estimates for knee isokinetic strength in Korean adults. These values may serve as preliminary reference information for clinical assessment and exercise prescription. Results should be interpreted with caution owing to limited sample sizes in some subgroups. Large, standardized, population-based studies are needed to refine these reference standards.