Sukho Lee

Associations between Physical Activity and Obesity Defined by Waist-To-Height Ratio and Body Mass Index in the Korean Population

Objective This study investigated the associations between physical activity and the prevalence of obesity determined by waist-to-height ratio (WHtR) and body mass index (BMI). Methods This is the first study to our knowledge on physical activity and obesity using a nationally representative sample of South Korean population from The Korea National Health and Nutrition Examination Survey. We categorized individuals into either non-obese or obese defined by WHtR and BMI. Levels of moderate-to-vigorous physical activity were classified as ‘Inactive’, ‘Active’, and ‘Very active’ groups based on the World Health Organization physical activity guidelines. Multivariable logistic regression was used to examine the associations between physical activity and the prevalence of obesity. Results Physical activity was significantly associated with a lower prevalence of obesity using both WHtR and BMI. Compared to inactive men, odds ratios (ORs) (95% confidence intervals [CIs]) for obesity by WHtR ≥0.50 were 0.69 (0.53–0.89) in active men and 0.76 (0.63–0.91) in very active men (p for trend = 0.007). The ORs (95% CIs) for obesity by BMI ≥25 kg/m2 were 0.78 (0.59–1.03) in active men and 0.82 (0.67–0.99) in very active men (p for trend = 0.060). The ORs (95% CIs) for obesity by BMI ≥30 kg/m2 were 0.40 (0.15–0.98) in active men and 0.90 (0.52–1.56) in very active men (p for trend = 0.978). Compared to inactive women, the ORs (95% CIs) for obesity by WHtR ≥0.50 were 0.94 (0.75–1.18) in active women and 0.84 (0.71–0.998) in very active women (p for trend = 0.046). However, no significant associations were found between physical activity and obesity by BMI in women. Conclusions We found more significant associations between physical activity and obesity defined by WHtR than BMI. However, intervention studies are warranted to investigate and compare causal associations between physical activity and different obesity measures in various populations.

Red Ginseng as an Ergogenic Aid: A Systematic Review of Clinical Trials

[Purpose] This systematic review was performed to summarize clinical trials assessing the effect of Red Ginseng (RG) supplementation on exercise performance and fatigue recovery. [Methods] Two English databases (PUBMED, MEDLINE) and two Korean databases (KISS, RISS) were used as systematic searching engines. We included only articles written in the English and Korean languages. Clinical trials, which evaluated exercise performance and recovery variables with RG supplementation, were included in this review. The methodological quality of all studies was assessed using the Cochrane Risk of Bias tool. Analysis was conducted with Comprehensive Meta-Analysis Version 3. [Results] In total, 135 potentially relevant studies were identified, and 14 studies were included. Overall, the aerobic capacity (VO2max, heart rate, time to exhaustion, shuttle run, and anaerobic threshold) exhibited no improvement with RG supplementation. In anaerobic capacity (peak power, mean power, and 30 m dash run), no significant improvements with RG supplementation was described in most of the studies. The antioxidant function predominantly measured by levels of superoxide dismutase (SOD) and malondialdehyde (MDA) showed mixed results. Red Ginseng’s effects on fatigue recovery were evaluated using lactate as a main outcome. Two studies observed significant effects while other 5 studies showed no significant effects. [Conclusion] The clinical effects of RG have been assessed in various conditions. Although the number of studies presented in this review is small and results of studies are mixed, it is hypothesized that this review article may provide useful guideline to design and conduct future studies investigating efficacy of RG supplementation on exercise performance and fatigue recovery in human trials.

Interaction of resistance training, electroacupuncture and Huang Qi supplementation on skeletal muscle function and GLUT4 protein concentration in rats

Objective To determine the effects and potential synergy of resistance training (RT), Huang Qi (HQ) herbal supplementation, and electroacupuncture (EA) on skeletal muscle mass, contractile properties, and components of the insulin signalling pathway in healthy Sprague Dawley rats. Methods Female Sprague Dawley rats were randomly assigned to one of five groups (n=8 each): control (CON), RT only, RT with EA (RT-EA), RT with HQ (RT-HQ), and RT combined with both EA and HQ (RT-EA-HQ). RT was performed using ladder climbing every other day for 8 weeks. Sparse-wave EA was applied for 15 min/day, 3 times/week for 8 weeks. HQ supplementation was provided via oral gavage daily for 8 weeks. Results RT significantly increased the muscle mass of the flexor hallucis longus (FHL) compared to CON. The isometric twitch and tetanic tension of the FHL in the RT-EA, RT-HQ, and RT-EA-HQ groups were significantly higher compared to CON and RT groups. RT-EA treatment (with or without HQ) significantly increased GLUT4 protein concentration but had no impact on Akt-2. Conclusions EA appears to be an effective treatment modality for increasing muscle mass and function when combined with RT. RT-EA may also be an effective method for improving glucose tolerance as a result of increases in GLUT4 protein concentration.

A cellular mechanism of muscle memory facilitates mitochondrial remodelling following resistance training

Referring to the muscle memory theory, previously trained muscles acquire strength and volume much faster than naive muscles. Using extreme experimental models such as synergist ablation or steroid administration, previous studies have demonstrated that the number of nuclei increases when a muscle becomes enlarged, which serves as a cellular muscle memory mechanism for the muscle. In the present study, we found that, when rats were subjected to physiologically relevant resistance training, the number of myonuclei increased and was retained during a long‐term detraining period. The acquired myonuclei were related to a greater degree of muscle hypertrophic and mitochondrial biogenesis processes following subsequent hypertrophic conditions. Our data suggest a cellular mechanism supporting the notion that exposing young muscles to resistance training would help to restore age‐related muscle loss coupled with mitochondrial dysfunction in later life.

Sport-based physical activity intervention on body weight in children and adolescents: a meta-analysis

ABSTRACT Controversial results reported in past research pertaining to the effectiveness of sport-based physical activity interventions on weight loss. The purpose of this study was to assess the impact of sport-based physical activity intervention on body weight in children and adolescents using a meta-analysis. Academic Search Complete, Education Source, ERIC, Medline, ProQuest, PsycINFO and SportDiscus databases were searched from January 2000 to April 2015. Eighteen studies met following inclusion criteria: sport-based intervention studies; subjects aged 6–18 years; reported body weight; published in peer-reviewed journals written in English. The mean intervention duration was 17.72 weeks. The overall effect size (ES) was 0.52 (Cohen’s d (ES) = 0.52, 95% CI = 0.08, 0.95, P = 0.021), using a random effects model. Moderator analyses results showed that the Q statistic for the sport type (individual sport or team sport, Qbetween (Qb) = 14.52, df = 1, P = 0.001) and diet control (Qbetween (Qb) = 8.85, df = 1, P = 0.001), explained the heterogeneity of ESs. Our study showed that there was a moderate overall effect of sport-based physical activity intervention on body weight reduction. The team sport type (ES = 1.05, 95% CI = 0.44, 1.66) and diet control group (ES = 0.84, 95% CI = 0.26, 1.41) appeared to be more effective in reducing body weight.

Acute effects of Kinesio taping on muscle function and self-perceived fatigue level in healthy adults

Abstract This study investigated the acute effects of Kinesio taping (KT) on muscular power, strength, endurance, and self-perceived fatigue level. This is a randomized, partial double-blind, crossover trial. Eighteen healthy adults (7 males [23.86 ± 1.68 years] and 11 females [24.82 ± 3.71 years]) were enrolled in this study. All subjects underwent three different trials which included no tap (NT), placebo tap (PT), and KT. Idividuals were assessed for peak and mean power, muscular strength and endurance, and self-perceived fatigue after each condition. The results revealed no significant differences in all variables (p > 0.05) except muscular endurance (F = 5.775, p = 0.007). Muscular endurance in the NT (58.28 ± 12.18 reps/min) condition was significantly higher than that in the KT (52.83 ± 11.76 reps/min) condition. These results suggest that KT on rectus femoris and the patella of the lower limb does not improve muscular function and self-perceived fatigue level. KT is unlikely to enhance exercise performance capacity in healthy adults.

Effect of previous strength training episode and retraining on facilitation of skeletal muscle hypertrophy and contractile properties after long-term detraining in rats

In the present study, we investigated the effects of previous strength training and retraining following long-term cessation of exercise on muscle mass and contractile properties. Female Sprague-Dawley rats (n=24) aged eight weeks were randomly assigned one of the four groups: control (CON), detraining (DT), training (TR), and retraining (RT). The training regimen consisted of climbing ladder 5×3 sets, once every third day for eight weeks with weight attached to the tail. The weight carried during each training session was initially 50% of body weight and progressively increased by 10% per session. The rats in DT were detained for 20 weeks followed by eight weeks strength training. The rats in the both TR and RT groups underwent eight weeks training. DT was age matched new training group while RT was retraining group after 20 weeks of detraining. Soleus, gastrocnemius, tibialis anterior, and flexor hallucis longus (FHL) muscles were harvested in order to measure the weight, and in situ contractile properties of FHL were measured including specific twitch tension (Spt) and specific tetanic tension (Spo). TR showed significant increase in muscle mass compared to CON (P<0.05). DT and RT showed significant increase in muscle mass when compared to all other groups (P<0.05). There was no statistical difference in Spt and Spo among the groups. The present study showed that previous strength training facilitates retraining-induced muscle hypertrophy following long-term cessation of exercise.

Physical Activity and Sedentary Behavior Are Independently Associated with Weight in Korean Adolescents.

Background This study examines the relationship between physical activity (PA), sedentary behavior (SB) and body weight in Korean adolescents. Methods: This study used a nationally representative sample of 72,368 South Korean adolescents, aged 13 to 18 years. The study sample was categorized according to BMI as follows: underweight, body mass index (BMI) <18.5; normal weight, 18.5 ≤ BMI < 23.0; overweight, 23.0 ≤ BMI < 25.0; and obese, 25.0 ≤ BMI. An analysis was then performed to determine if meeting the recommended guidelines for PA frequency (5 times/week ≤) and amount of SB (<2 hours/day) was associated with weight category. Results: The percentage of normal weight adolescents was 54.3% while the percentages of underweight, overweight, and obese adolescents were 27.4%, 10.2%, and 8.1%, respectively. Significantly fewer underweight and obese adolescents met PA guidelines compared to normal weight adolescents. In addition, underweight, overweight, and obese adolescents had significantly higher SB scores. Conclusion: The present study indicates that in Korean adolescents, physical activity and sedentary behavior are independently associated with weight status. Overweight, obese and underweight Korean adolescents should all be independently monitored for management of health-related behaviors.

Jumping Exercise Restores Stretching-Induced Power Loss in Healthy Adults

Th e purpose of this study was to examine the acute eff ects of jumping exercise (JE) immediately aft er diff erent stretching protocols on fl exibility and power in healthy adults. Th is study was conducted with a balanced crossover design. Th irteen healthy males (25.4±3.46 years old) voluntarily participated in this study. All participants randomly completed four trials, including three diff erent stretching protocols; 1) static stretching (SS), 2) dynamic stretching (DS), 3) proprioceptive neuromuscular facilitation stretching (PNFS), and 4) a non-stretching control (NS) followed by the JE with seven-day intervals between tests. JE was composed of three sets of fi ve tuck jumps. Flexibility was determined by the ability to perform a straight leg raise (SLR) and power by vertical jump performance (VJP). Both SLR and VJP were measured at four time points; 1) baseline, 2) post-jogging, 3) post-stretching, and 4) post-JE; 4 × 4 repeated measures analysis of variances were applied. Th ere were signifi cant interaction eff ects on SLR (F=8.935, p<.001) and VJP (F=3.965, p=.009). Th e SLR score increased in all stretching protocols except the NS protocol post-stretching and postJE. Aft er stretching, the VJP score decreased in the NS (-2.6%), SS (-3.6%), and PNFS (-4.4%) protocols but maintained a positive score for the DS (1.8%) protocol. However, the VJP score recovered to the previous value in the SS (3.2%) and PNFS (6.5%) protocols aft er the jumping exercise. Th e present study suggests that jumping exercise immediately aft er SS and PNFS protocols could be an effi cient program for restoring stretching-induced power loss in healthy adults.