Purpose The study examined the effects of a 12-week high intensity circuit training (HICT) on abdominal fat, physical fitness, blood lipids, and insulin resistance in middle-aged obese women. Methods Thirty obese women, aged 32-48 yrs, were recruited and randomly assigned to either HICT group (TR; n = 15) or control group (CON; n = 15). Subjects in the TR group participated in HICT of which resistance exercise and aerobic exercise were performed with a duration of 40 min/session and 3 sessions/wk for 12 weeks, whereas subjects in the CON group were asked to maintain their normal life patterns. Dependent variables included abdominal fat area, body composition, physical fitness, blood lipids profiles, and insulin resistance index. Analysis of variance with repeated measures with Bonferroni corrections was used to compare the outcomes between two groups. Results Main findings of the present study were as follows: 1) compared to the CON group, the TR group had significant reductions in overall (i.e., body mass index and percent body fat) and abdominal obesity (i.e., waist circumference, total abdominal fat area, visceral fat area, subcutaneous fat area, and visceral fat area-subcutaneous fat area ratio), 2) compared to the CON group, the TR group had significant improvements in health-related physical fitness (i.e., muscular strength, muscular endurance, muscle power, flexibility, balance, and cardiorespiratory endurance), and 3) compared to the CON group, the TR group had significant improvements in fasting lipids, glucose, insulin, and insulin resistance. Conclusions The current findings of the study suggested that HICT would be an effective exercise intervention to improve metabolic complications associated with obesity and poor physical fitness in obese middle-aged women.
PURPOSE This study investigated the effects of moderate-intensity continuous exercise (MICE) and high-intensity interval exercise (HIIE), performed postprandially, on blood glucose, blood pressure, and blood lactate levels in men aged 40–50 with prediabetes and prehypertension. METHODS Twelve men with prediabetes and prehypertension were selected. After consuming a liquid meal, the participants participated in three trials: MICE, HIIE, and a non-exercise condition, with a one-week washout period between each trial. The trials were conducted in a counter-balanced manner to ensure equal energy expenditure across conditions. The intensity of the MICE trial was set at 70% of the heart rate reserve (HRR), whereas the HIIE trial alternated between 50% and 90% of HRR for 30 minutes. Blood glucose, blood pressure, and blood lactate levels were measured at various time points during each trial, and a two-way repeated-measures ANOVA was used for analysis. RESULTS 1) In the MICE trial, significant reductions were observed in blood glucose (at 15 and 30 minutes during exercise), systolic blood pressure (SBP) (at 50 minutes post-exercise), and diastolic blood pressure (DBP) (at 20, 40, 50, and 60 minutes post-exercise). 2) In the HIIE trial, significant reductions in blood glucose (at 15 and 30 minutes during exercise), SBP (at 40 minutes post-exercise), and DBP (at 40 minutes post-exercise) were observed. Blood lactate levels significantly increased. 3) When comparing the two exercise trials, blood glucose in the HIIE trials showed a recovery trend post-exercise, and blood lactate levels increased to a greater extent. CONCLUSIONS These findings suggest that both MICE and HIIE effectively lower blood glucose during exercise, but HIIE causes a more rapid post-exercise increase in blood glucose compared to MICE. In addition, MICE results in a smaller rise in blood lactate. Therefore, MICE is recommended for improving prediabetes and prehypertension. Future research should compare these effects in healthy individuals and examine long-term adaptations to repeated exercise.
Purpose The purpose of this study was to evaluate the moderate to vigorous physical activity(MVPA) and sedentary time measured by accelerometer. Furthermore, the level of physical activity and adherence rate of physical activity guideline(PAG) were compared with the self-reported questionnaire. Methods The MVPA, sedentary time, and adherence rate of PAG according to age and sex were examined to people who agreed to wear accelerometers among the participants of the 2014-2015 Korea National Health and Nutrition Examination Survey. To compare the relationship between accelerometer and self-reported questionnaire, Chi-squared test and Spearman correlation analysis were performed. Results The MVPA of the accelerometer-total(AT) was 40.6 minutes/day for men and 31.1 minutes/day for women. Sedentary time was 502.9 minutes/day for men and 498.9 minutes/day for women. The MVPA of accelerometer-bout(AB) estimates was 16.4 minutes/day for men and 14.2 minutes for women. On the other hand, the MVPA of the self-report was 95.8 minutes for men and 64.3 minutes for women, and the sedentary time was 471.2 minutes for men and 455.2 minutes for women. The adherence rate of PAG was 55.6% of the self-report, 56.1% of the AT, and 21.4% of the AB. The correlation between self-report and accelerometer was statistically significant(p < 0.01), but showed a weak correlation coefficient(rho=0.112-0.351). There was no association between AB and self-report(p < 0.01). The sensitivity and specificity of the self-report were 71.3% and 48.6%, respectively. The positive and negative predictive values of the self-report were 27.5% and 86.1%, respectively. Conclusions As a result of this study, self-reported physical activity level by questionnaire had more MVPA and less sedentary time than the accelerometer-determined physical activity. In addition, the adherence rate of the PAG differed from accelerometer and self-report. The difference was significantly increased when comparing AB with the self-report. Therefore, great care must be taken when interpreting accelerometer and self-report questionnaire. Further research will be needed on specific methods that can be used by complementing the two measurement tools.
Purpose The purpose of the study was to determine difference of body composition, bone mineral density and health-related fitness by physical activity level in young women. Methods A total of 90 women aged 19-29 years participated in this study. The subjects were divided into three groups (low, middle, and high level) according to the physical activity level estimated by bone-specific physical activity questionnaire(BPAQ). Body height and weight were measured. Body composition parameters including four sites of bone mineral density(BMD) were estimated by DXA (Hologic, QDR-4500, USA). Health-related fitness tests was assessed using sit & reach, grip strength, sit-ups, and VO2max. Statistical analysis was performed using SAS version 9.4. All data were presented in terms of means and standard deviations. One-way ANOVA was applied to determine difference of dependent variables by physical activity level. Duncan's multiple range test was used as a post-hoc test. The statistical significance level was set at p < .05. Results There were significant differences on body weight(F = 4.867, p = .01), body mass index(F = 5.053, p = .008) and fat-free mass(F = 8.364, p = .0001) among the three groups. Significant differences were found on whole body BMD(F = 16.730, p = .0001), lumbar BMD(F = 11.480, p = .0001), femur BMD(F = 42.182, p = .0001) and forearm BMD(F = 5.560, p = .005) among the three groups. There were also significant differences on sit and reach(F = 11.433, p = .0001), sit-ups(F = 17.972, p = .0001), VO2max(F = 3.106, p = .05) and duration of GXT(F = 7.479, p = .001). Conclusions There were differences on body composition, bone mineral density and health-related physical fitness by physical activity levels. Nevertheless, the questionnaire used in this study was not able to judge participation in various exercise types including aerobic exercise or resistance exercise. Therefore, in the future study, longitudinal study considering various types of physical activity and dietary intake will be needed.
[Purpose] The purpose of this study was to examine the change of muscle damage markers after maximal eccentric exercise and to verify the difference of recovery according to ACTN3 gene polymorphism. [Methods] Fifty healthy males participated in this study. Subjects performed 25 times/1 set (total 2 set) maximal eccentric contractions of the elbow flexor muscles on a modified preacher curl machine with a between-sets rest time of 5 min. Maximal isometric contraction (MIC) was measured 6 times (pre, post, after 24 h, 48 h, 72 h and 96 h). Muscle soreness (SOR) was measured 5 times (pre, after 24 h, 48 h, 72 h and 96 h). Blood samples were collected 5 times (pre, after 24 h, 48 h, 72 h and 96 h). ACTN3 gene polymorphisms were identified using polymerase chain reaction (PCR). Data were analyzed using a 2-way repeated measure ANOVA and post hoc Bonferroni test. [Results] Analysis of ACTN3 gene polymorphism revealed the following distribution: 22% RR (n=11), 50% RX (n=25), and 28% XX (n=14). Individuals were classified into the RR homozygote group (n=11) and the X-allele group (n=39). MIC showed a significant difference between groups and interaction (p<.05). The groups differed significantly in MIC at 48 h, 72 h, and 96 h after exercise and the X-allele group decreased more than the RR homozygote group. The groups differed significantly in muscle soreness and interaction (p<.05). SOR in the X-allele group was significantly higher than in the RR homozygote group at 24 h after exercise. Although blood CK activity was lower in the RR homozygote group than in the X-allele group, but there was no significant difference between the groups (p>.05). [Conclusion] The RR homozygote group showed lower muscle strength reduction rate, muscle soreness and blood CK activity than the X-allele group. This indicates that RR individuals have a lower risk of exercise-induced muscle damage than those with an X-allele.
