Research on physical activity and health is actively being conducted. In the Korea National Health and Nutrition Examination Survey (KNHANES), the Global Physical Activity Questionnaire (GPAQ) was newly introduced in 2014. The purpose of this study was to investigate the levels of physical activity and related factors in Koreans who were assessed through the GPAQ by dividing the physical activity by occupation, leisure, and transport domain. This study used data from the KNHANES (2014-2016), the study population of which included 17,357 participants aged 12 to 80 years. We compared the differences in physical activity by sociodemographic factors, health-related factors, and psychological health-related factors. Moreover, we also compared the mean metabolic equivalent of task and daily sitting time according to physical activity domain by sex and age group. Finally, we investigated the sociodemographic factors, health-related factors, and psychological health-related factors that significantly affect the average physical activity per week. The various factors were found to differ in the frequency of physical activity levels. In addition, there was a difference in the amount of physical activity per occupation, leisure, and transport domain in each age group. Finally, age, sex, high-density lipoprotein cholesterol levels, arthritis, allergic rhinitis and sinusitis, sleeping time, and perceived health status significantly affected physical activity. The levels of physical activity significantly differed by sociodemographic factors, health-related factors, and psychological health-related factors. There was also a difference in the physical activity levels according to the age and sex per each domain of physical activity.

Purpose: The study aimed to assess the average time to return to play following surgery for chronic lateral ankle instability in athletes.
Methods: A literature search was conducted (1976 to 2019) by two independent reviewers using the Medline, Embase, and Cochrane library databases. Articles were retrieved by an electronic search using individual keywords (“lateral ankle instability,” “surgery,” “operation,” “return to sport,” “return to play”) and their combinations. Studies that met the inclusion criteria were assessed for pertinent data.
Results: Six randomized controlled trials were included in this analysis. The mean follow-up period was 44.8 months (range, 31.8-58.1 months) in 219 patients (male, 126; female, 113). The mean age was 23.2 years (range, 18.2-28.2 years). Different criteria for returning to sports were used in each paper. In the papers included in this study, different methods and definitions were used for the postoperative recovery method for lateral ankle instability injury. The average time until return to play was 16.53 weeks.
Conclusion: There are limitations to the application of different surgical techniques and data from different athletes for chronic lateral ankle instability. However, these results suggest that sports physicians evaluate the surgical outcome and may be utilized as reference data for informing the athletes about their time until return.

Purpose: This study aimed to investigate the effect of hospital-based intensive rehabilitation program after ankle ligament operation.
Methods: A total of 35 patients were included in this randomized controlled trial. Fifty-minute sessions of hospital-based rehabilitation were performed three times weekly for 12 weeks in the intervention group. Home-based exercise was conducted in the control group. Outcomes were evaluated at baseline, 12 weeks, and 16 weeks. The primary outcome was measured using the Foot and Ankle Outcome Score (FAOS). Secondary outcomes included the American Orthopedic Foot and Ankle Society (AOFAS) score, ankle strength measured using an isokinetic device, fall index measured using a Tetrax posturography device, and the Berg Balance Scale.
Results: Significant improvements in FAOS, AOFAS, ankle strength, and fall index were found in the intervention group after performing the hospital-based rehabilitation (all p<0.05) and these improvements were sustained at T2 (all p<0.05). Between-group comparisons demonstrated significantly greater improvements in FAOS, AOFAS, ankle strength, and fall index in the intervention group than those in the control group at both T1 (all p<0.05), and T2 (all p<0.05).
Conclusion: The rehabilitation program in this study improved postoperative pain, sports function, quality of life, and strength and balance of the ankle significantly better than home-based self-care. Therefore, we recommend hospital-based systematic rehabilitation programs after surgical treatment for chronic ankle instability.

Purpose: The main purpose of this study was to compare the relationships between physical activity (measured using an accelerometer vs. self-reported) and cardiovascular disease risk factors. Differences in accelerometry physical activity between 10-minute bouts and total bouts were also compared.
Methods: Data originated from the Korea National Health and Nutrition Examination Survey. Logistic regression was used to predict cardiovascular disease risk from physical activity levels.
Results: Self-reported physical activity could not significantly predict the odds of having cardiovascular risk. However, the insufficiently active group classified according to the total-bout physical activity had significantly greater odds of having hypertension or prehypertension (odds ratio [OR], 1.35; 95% confidence interval [95% CI], 1.00-1.82), diabetes mellitus (OR, 1.77; 95% CI, 1.01-3.19), and dyslipidemia (OR, 1.65; 95% CI, 1.17-2.36) than the highly active group. Regarding the 10-minute bout physical activity, the inactive group had significantly greater odds of having only hypertension or prehypertension (OR, 1.67; 95% CI, 1.02-2.76) than the highly active group.
Conclusion: Total-bout physical activity measured using an accelerometer could significantly predict the cardiovascular disease risk compared to 10-minute bout physical activity. However, self-reported physical activity could not significantly predict the cardiovascular disease risk.

Purpose: The purpose of this study was to investigate the muscle activities of the brachioradialis and extensor carpi radialis longus according to the type of backhand stroke in badminton.
Methods: To measure the muscle activities, we used electromyography (EMG) equipment to measure EMG values by performing maximal voluntary contraction (MVC) of the forearm muscles, which depends on the type of backhand stroke. With these values, the %maximum voluntary isometric contraction values were obtained. The data were calculated using SPSS ver. 21.0 and one-way repeated measures analysis of variance with a post-hoc least significant difference test.
Results: In this study, the backhand clear achieved higher maximum muscle activity values than those by the backhand push, under clear, and drive in the brachioradialis. The backhand smash achieved higher maximum muscle activity values than those by the backhand push in the extensor carpi radialis longus.
Conclusion: The backhand clear is associated with a higher injury rate than those associated with the backhand push, under clear, and drive. The backhand smash is associated with a higher rate of the occurrence of tennis elbow than that associated with the backhand push. To prevent injuries, it is considered that the forearm's strength, stretching before and after exercise, and sufficient time to rest are important.

Purpose: The first aim of this study was to retrospectively survey sports injuries among 608 athletes participating in 26 sport events. The second aim was to compare the characteristics of sports injuries depending on the occurrences during the high school and university periods.
Methods: The data were collected based on the daily injury report form proposed by the International Olympic Committee from March to June 2019.
Results: Four hundred and thirty-nine athletes (313 men) of 608 participated athletes experienced a total of 747 sports injuries, indicating 0.7 injuries per 1,000 athlete exposures (AEs). The incidence rate during the university period was 6.1 injuries/1,000 AEs, which was approximately two-fold higher than that during the high school period (2.8 injuries/1,000 AEs). The reported frequency of injuries was the highest among long distance athletics (n=60, 8.0%), and in each subgroup as well.
Conclusion: Many more injuries were incurred during practice wherein injuries in long-distance athletics were the most common than in competition athletics; handball injuries and taekwondo injuries were the most common during high school and university, respectively. The most contact injuries occurred in taekwondo and most noncontact injuries occurred in gymnastics during high school and in badminton during university. The most commonly affected body parts were the knee, shoulder, and ankle. Severe injuries were the most frequent in long distance athletics, and emergent situations were the most common in taekwondo.

Intermetatarsal coalition (IC) is very rare; although few cases have been reported in foreign orthopedic journals, these have not originated in our country. We report the case of a 20-year-old man who complained of pain in the left forefoot only during long distance running (3 km). On examination, his foot shape, skin appearance, and gait were normal, with no plantar keratosis; however, the radiograph revealed coalition between the fourth and fifth metatarsals. Surgical excision was performed. In the histopathologic study, fibrous coalition was confirmed. This paper reports an uncommon case involving surgical excision of IC in the military service, involving active sport activity.