The purpose of this study was to evaluate the effects of a 12-week non-contact exercise intervention on body composition and health-related physical fitness in adults.
One hundred adults were initially enrolled; however, ninety-seven participants (men: n = 41, women: n = 56) completed the study. The non-contact exercise was performed for 12 weeks using a smart tracker (Charge 4, Fitbit, USA) and mobile phone applications. The non-contact exercise program included resistance, aerobic, and flexibility exercises.
The results showed that percent body fat (
Our findings suggest that 12 weeks of non-contact exercise improves body composition and health-related physical fitness. Wearable technologies encourage individuals to modify their lifestyles by increasing physical activity and achieving the goal of maintaining health conditions among adults.
As the coronavirus disease 2019 (COVID-19) pandemic continues to develop in almost all regions of the world, the government has implemented various protective measures in response, including the closure of schools and universities, restrictions on travel and sporting events, and bans on social gatherings [
Digital healthcare technology has been developing rapidly in recent years, with various health-promoting equipment being developed. Owing to advances in industrial technology, wearable technology can provide new opportunities to motivate individuals to improve their PA levels, including mobile phone applications, smartwatches, wristbands, and other wearable devices [
One hundred adults (aged:33.97 ± 11.20 years) were initially enrolled; however, ninety-seven participants (men: n = 41, women: n = 56) completed the study. Three participants dropped out of the study because of personal reasons. All study procedures were approved by the Institutional Review Board of Konkuk University and conducted in accordance with the principles of the Declaration of Helsinki. Written informed consent was obtained from all the participants. Participants’ characteristics are presented in
Non-contact exercise was performed for 12 weeks using a smart tracker (Charge 4, Fitbit, USA) and mobile phone applications. Individual exercise intervention management was performed using an AI-Fit web page (Korea Institute of Industrial Technology, KITECH), which can be used by linking the Fitbit APP. The AI-Fit web page sets participants’ exercise intensity through body composition, health-related physical fitness measurement data, and questionnaire, and based on this, presents a customized exercise program. In addition, the non-contact exercise intervention was conducted more efficiently through the manager checking the user data through the AI-Fit web page. Feedback was provided in real-time through a messenger service (Kakao Talk) linked to the AI-Fit web page. The non-contact exercise program included resistance, aerobic, and flexibility exercises.
Resistance exercise was performed two days per week and for 60 min per day. The resistance exercise consisted of 10 min of dynamic stretching, 40 min of the main exercise, and 10 min of static stretching. Resistance exercises comprised push-ups, side banding, arm curls, lunges, squats, donkey kicks, leg raises, burpee test, bridging, and planking. The training intensity was set at three sets of 10-15 repetitions (beginner:10 reps, intermediate:12 reps, advanced:15 reps) at a perceived exertion value of 7 or 8 on the OMNI-Resistance Exercise Scale of perceived exertion (0: extremely easy to 10: extremely hard).
Aerobic exercise was performed five days per week for 50 min per day. The aerobic exercise consisted of 10 min of dynamic stretching, 30 min of the main exercise, and 10 min of static stretching. Resistance exercises included walking, jogging, running, and cycling. The training intensity was set at a maximum heart rate (HRmax) of 60-85% (beginner: 60%, intermediate: 60-70%, advanced: 70-85%).
Flexibility exercise was performed five days per week for 10 minutes per day. The flexibility exercise comprised stretching the inside of the legs, stretching the front of the legs, stretching behind the legs, stretching the hips, stretching the sides, stretching the stomach, stretching the lower arm, stretching in front of the chest/shoulder, stretching the back and shoulders, and stretching the neck. The training intensity was set to a minimum of 30 seconds for each movement. The details of the non-contact exercise program are presented in
Body composition was measured using bioelectrical impedance analysis (BIA) with InBody 770 (Inbody, Seoul, Korea). Before measuring body composition, fasting was performed for 8 h and metallic materials were removed. Body composition, including weight, body mass index (BMI), fat mass, percent body fat, fat-free mass, and skeletal muscle mass was analyzed.
Health-related physical fitness tests included isometric muscle strength (handgrip strength; T.K.K. 5001, TAKEI, Tokyo, Japan), muscular endurance (sit-ups), flexibility (sit- and-reach; T.K.K. 5403, Flexion-D, Tokyo, Japan), and cardiorespiratory fitness (maximal oxygen uptake: VO2max; Aero bike 75XLIII, Konami, Tokyo, Japan).
The power test was performed using G*Power 3.1.9.2 (Franz Faul, University of Kiel, Kiel, Germany) at an effect size of 0.35, a significance level of 0.05 (α=0.05), and a power of 0.8 for all statistical tests. G*Power showed that 81 participants had sufficient power for this study. Statistical analyses were performed using the SPSS software version 26 (IBM Corp., Armonk, NY, USA). The mean and standard deviation were calculated. The normality of the distribution of all dependent variables was verified using the Shapiro-Wilk test. One-way repeated measures ANOVA was used to determine changes among the three periods (pre-test, middle-test, and post-test) by dependent variables. The effect size was computed as partial eta squared values (ηp2; small: ≥.01, medium: ≥.06, large: ≥.14). The statistical significance level was set at 0.05.
The present study examined the effects of non-contact exercise intervention for 12 weeks on body composition and health-related physical fitness in adults. The findings of this study revealed that the non-contact exercise intervention reduced percent body fat and increased fat-free mass, skeletal muscle mass, hand grip strength, sit-and-reach, sit-ups, and VO2max.
In recent years, studies on the effects of mobile health on body composition have drawn attention [
Since health-related physical fitness is associated with the prevalence and mortality of diseases, it is essential to manage health-related physical fitness by increasing PA [
The present study revealed that 12 weeks of non-contact exercise intervention improves body composition and health-related physical fitness among adults. Wearable technologies encourage individuals to improve their lifestyles by increasing PA and achieve the goal of maintaining health in this population.
This research was supported by the Culture, Sports, and Tourism R&D Program through the Korea Creative Content Agency grant funded by the Ministry of Culture, Sports, and Tourism in 2020 (Project Name: Development of customized smart fitness service to support the personal life span; project number: SR202006002; contribution rate:100%).
Physical characteristics of participants.
Variables | Total (n = 97) | Men (n = 41) | Women (n = 56) |
---|---|---|---|
Age (yrs) | 33.97 ± 11.20 | 30.17 ± 9.51 | 37.75 ± 11.60 |
Height (cm) | 166.88 ± 8.61 | 174.26 ± 4.59 | 161.49 ± 6.61 |
Weight (kg) | 67.80 ± 12.36 | 75.52 ± 10.60 | 62.15 ± 10.39 |
BMI (Kg/m2) | 24.28 ± 3.72 | 24.83 ± 3.03 | 23.88 ± 4.14 |
Values are expressed as mean ± SD. BMI: body mass index.
Non-contact exercise intervention program.
Frequency | Intensity | Exercise time (min) | Exercise types | ||
---|---|---|---|---|---|
Resistance exercise | 2 days / week | OMNI scale 7-8 | Beginner: 10 reps | Stretching: 10 min | dynamic stretching |
Intermediate: 12 reps | Main exercise (3 sets): 40 min | push-ups, side-banding, arm curls, lunges, squats, donkey kick, leg raises, burpee test, bridging, planking | |||
Advanced: 15 reps | Stretching: 10 min | static stretching | |||
Aerobic exercise | 5 days / week | HRmax 60~85% | Beginner: 60% | Stretching: 10 min | dynamic stretching |
Intermediate: 60-70% | Main exercise: 30 min | walking, jogging, running, bicycle | |||
Advanced: 70-85% | Stretching: 10 min | static stretching | |||
Flexibility exercise | 5 days / week | Minimum of 30 seconds for each movement | Main exercise: 10 min | stretching inside the legs, stretching front of the legs, stretching behind the legs, hip stretching, stretching the sides, stretching the stomach, back stretch, stretching the lower arm, stretching in front of the chest/shoulder, stretching on the back and shoulders, stretching the neck |
HRmax: maximum heart rate.
Changes in body composition among the pre-test, middle-test, and post-test.
Variables | Pre-test | Middle-test | Post-test | prob> |
ES(ηp2) | |
---|---|---|---|---|---|---|
Weight (kg) | 67.80 ± 12.36 | 67.90 ± 12.49 | 67.89 ± 12.48 | .306 | .737 | .003 |
BMI (kg/m2) | 24.28 ± 3.72 | 24.43 ± 3.82 | 24.29 ± 3.67 | 1.211 | .285 | .012 |
Fat mass (kg) | 18.63 ± 7.64 | 18.49 ± 7.54 | 18.35 ± 7.55 | 3.243 | .051 | .033 |
Percent body fat (%) | 27.46 ± 9.24 | 27.13 ± 8.92 | 26.93 ± 8.97 | 4.993 | .016 * | .049 |
Fat-free mass (kg) | 49.17 ± 10.56 | 49.41 ± 10.71 | 49.91 ± 10.81 | 4.690 | .024 * | .047 |
Skeletal muscle mass (kg) | 27.31 ± 6.46 | 27.46 ± 6.57 | 27.53 ± 6.56 | 5.623 | .004 ** | .055 |
Values are expressed as mean ± SD. ES: effect size, BMI: body mass index. Significant difference among the groups: *
Changes in health-related physical fitness among the pre-test, middle-test, and post-test.
Variables | Pre-test | Middle-test | Post-test | prob> |
ES(ηp2) | |
---|---|---|---|---|---|---|
Hand grip strength (kg) | 31.03 ± 9.71 | 31.86 ± 9.45 | 32.91 ± 9.91 | 12.167 | .000 *** | .112 |
Sit-and-reach (cm) | 9.24 ± 10.64 | 9.80 ± 10.13 | 11.21 ± 10.09 | 20.497 | .000 *** | .176 |
Sit-ups (n) | 24.01 ± 11.47 | 25.81 ± 11.53 | 28.34 ± 12.43 | 42.107 | .000 *** | .305 |
VO2max (mL/kg/min) | 30.96 ± 7.90 | 32.16 ± 8.11 | 32.31 ± 7.86 | 4.311 | .037 * | .043 |
Values are expressed as mean ± SD. ES: effect size, VO2max: maximal oxygen uptake. Significant difference among the groups: *