Cardiometabolic risk factors among children who are affected by overweight, obesity and severe obesity

Background

The increasing severity of obesity is expected to lead to more serious health effects. However, there is limited information on the prevalence and clinical characteristics of cardiometabolic risk factors in severely children affected by obesity in Malaysia. This baseline study aimed to investigate the prevalence of these factors and their association with obesity status among young children.

Methods

In this study, a cross-sectional design was employed using the baseline data obtained from the My Body Is Fit and Fabulous at school (MyBFF@school) intervention program involving obese school children. Obesity status was defined using the body mass index (BMI) z-score from the World Health Organization (WHO) growth chart. Cardiometabolic risk factors presented in this study included fasting plasma glucose (FPG), triglycerides (TGs), total cholesterol, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), blood pressure, acanthosis nigricans, insulin resistance (IR), and MetS. MetS was defined using the International Diabetes Federation (IDF) 2007 criteria. Descriptive data were presented accordingly. The association between cardiometabolic risk factors, such as obesity status, and acanthosis nigricans with MetS was measured using multivariate logistic regression, which was adjusted for gender, ethnicity, and strata.

Results

Out of 924 children, 38.4% (n = 355) were overweight, 43.6% (n = 403) were obese, and 18% (n = 166) were severely obese. The overall mean age was 9.9 ± 0.8 years. The prevalence of hypertension, high FPG, hypertriglyceridemia, low HDL-C, and the presence of acanthosis nigricans among severely children affected by obesity was 1.8%, 5.4%, 10.2%, 42.8%, and 83.7%, respectively. The prevalence of children affected by obesity who were at risk of MetS in <10-year-old and MetS >10-year-old was observed to be similar at 4.8%. Severely children affected by obesity had higher odds of high FPG [odds ratio (OR) = 3.27; 95% confdence interval (CI) 1.12, 9.55], hypertriglyceridemia (OR = 3.50; 95%CI 1.61, 7.64), low HDL-C (OR = 2.65; 95%CI 1.77, 3.98), acanthosis nigricans (OR = 13.49; 95%CI 8.26, 22.04), IR (OR = 14.35; 95%CI 8.84, 23.30), and MetS (OR = 14.03; 95%CI 3.97, 49.54) compared to overweight and children affected by obesity. The BMI z-score, waist circumference (WC), and percentage body fat showed a significant correlation with triglycerides, HDL-C, the TG: HDL-C ratio, and the homeostatic model assessment for IR (HOMA-IR) index.

Conclusions

Severely children affected by obesity exhibit a higher prevalence of and are more likely to develop cardiometabolic risk factors compared to overweight and children affected by obesity. This group of children should be monitored closely and screened periodically for obesity-related health problems to institute early and comprehensive intervention.

Prevalence and clinical characteristics of metabolically healthy obese versus metabolically unhealthy obese school children

INTRODUCTION

Children with obesity in the absence of traditional cardiometabolic risk factors (CRF) have been described as metabolically healthy obese (MHO). Children with MHO phenotype has a favorable metabolic profile with normal glucose metabolism, lipids, and blood pressure compared to children with metabolically unhealthy obese (MUO) phenotype. This study aimed to compare several parameters related to obesity between these two groups and to examine the predictors associated with the MHO phenotype.

METHODS

This study included a cross-sectional baseline data of 193 children with obesity (BMI z-score > +2 SD) aged 8-16 years enrolled in MyBFF@school program, a school-based intervention study conducted between January and December 2014. Metabolic status was defined based on the 2018 consensus-based criteria with MHO children had no CRF (HDL-cholesterol > 1.03 mmol/L, triglycerides ≤ 1.7 mmol/L, systolic and diastolic blood pressure ≤ 90^th percentile, and fasting plasma glucose ≤ 5.6 mmol/L). Those that did not meet one or more of the above criteria were classified as children with MUO phenotype.

RESULTS

The prevalence of MHO was 30.1% (95% CI 23.7 - 37.1) among schoolchildren with obesity and more common in younger and prepubertal children. Compared to MUO, children with MHO phenotype had significantly lower BMI, lower waist circumference, lower uric acid, higher adiponectin, and higher apolipoprotein A-1 levels (p < 0.01). Multivariate logistic regression showed that adiponectin (OR: 1.33, 95% CI 1.05 - 1.68) and apolipoprotein A-1 (OR: 1.02, 95% CI 1.01 - 1.03) were independent predictors for MHO phenotype in this population.

CONCLUSIONS

MHO phenotype was more common in younger and prepubertal children with obesity. Higher serum levels of adiponectin and apolipoprotein A-1 increased the possibility of schoolchildren with obesity to be classified into MHO phenotype.

TG: HDL-C Ratio as Insulin Resistance Marker for Metabolic Syndrome in Children With Obesity

Insulin resistance (IR) is an important variable in the diagnosis of metabolic syndrome (MetS). Currently, IR is not part of the existing pediatric definition of MetS, instead elevated fasting blood glucose (FBG) is measured as an indicator of hyperglycemia. Arguably, many obese children with severe IR are still able to regulate their FBG well. Hence, this study aimed to assess the utility of triglyceride-to-high-density lipoprotein cholesterol (TG : HDL-C) ratio as an IR marker in the modeling of pediatric MetS among children with obesity using structural equation modeling (SEM). A total of 524 blood samples from children with obesity (age 10-16 years old) were analyzed for FBG, lipids, insulin, leptin, and adiponectin. Both exploratory (EFA) and confirmatory factor analysis (CFA) were used to examine TG : HDL-C ratio as an IR marker in pediatric MetS. EFA shows that TG: HDL-C ratio (standardized factor loading = 0.904) groups together with homeostasis model assessment-estimated insulin resistance (HOMA-IR) (standardized factor loading = 0.664), indicating a strong correlation to the IR factor. Replacing FBG with TG: HDL-C ratio improved the modeling of MetS structure in children with obesity. Our MetS model of TG: HDL-C ratio as IR component shows comparable model fitness indices (goodness of fit, Akaike's information criterion, and Bayesian information criterion) with leptin:adiponectin ratio (platinum standard for adiposity:IR marker) model. The least model fit was seen when using FBG as an IR surrogate. TG : HDL-C ratio performed better as IR surrogate in MetS structures (standardized factor loading = 0.39) compared to FBG (standardized factor loading = 0.27). TG: HDL-C ratio may be considered as an IR component in pediatric MetS.

Orthoses versus gait retraining: Immediate response in improving physical performance measures in healthy and medial knee osteoarthritic adults

The conservative techniques of treating knee osteoarthritis (kOA) include wearing orthoses such as knee braces and laterally wedged insoles and applying gait modification techniques such as toe-in gait and toe-out gait. This study aimed at assessing the immediate effects of these techniques in improving physical function of healthy and kOA participants. Five Osteoarthritis Research Society International (OARSI) recommended performance-based tests were randomly applied to measure physical function: (1) 30-second chair stand test (30CST), (2) 40-m (4 × 10) fast-paced walk test (40FPW), (3) stair climb test (SCT), (4) timed up and go test (TUGT) and (5) 6-minute walk test (6MWT) during a single-visit on 20 healthy and 20 kOA patients (age: 59.5 ± 7.33 and 61.5 ± 8.63 years, BMI: 69.95 ± 9.86 and 70.45 ± 8.80 kg/m²). The interventions included natural gait, toe-out gait, toe-in gait, laterally wedged insoles and knee brace. Analysis was performed through repeated-measures ANOVA and independent sample t-test. 30CST and TUGT showed no significant differences for the five test conditions (p > 0.05). Toe-out showed profound effects via pairwise comparison in impairing the physical function while knee brace improved it during 40FPW, SCT and 6MWT. In general, all the tested conservative techniques except laterally wedged insoles had immediate effects on physical performance measures in both healthy and medial knee osteoarthritis participants. The valgus knee brace improved the parameters the most, while toe-out gait impaired them the most. Future studies can develop strategies for improving gait retraining methods on the basis of issues identified by this study.

Contribution of the arm segment rotations towards the horizontal ball and racket head velocities during forehand long shot and drop shot services in table tennis

Service is assumed important in table tennis because an effective service may allow the serving player to control over the game; hence, the aim of this study was to determine the contribution of arm segment rotations towards ball impact during forehand service. Sixteen shake-hand grip collegiate table tennis athletes had participated in the study. It was revealed that by increasing the radial deviation angular velocity will increase the ball and racket velocities during drop shot service. Furthermore, it was revealed that increasing the wrist palmar flexion and radial deviation will enhance the racket velocity at impact during long shot service. However, it was recommended to the players not to concern on racket speed and arm segment rotations during contact phase as it could not accelerate the ball at impact during long shot service. Although it was the same forehand service, different length of flight ball lead to different contributions of arm segment rotations towards ball impact. The present findings highlight several better postures to increase racket and ball speed at impact during forehand long shot and drop shot services among advanced and intermediate players. Other ranked players may find this study useful as a fundamental understanding on kinematics serving arm.

Dietary Practices and Meal Patterns among Overweight and Obese School Children in Malaysia: Baseline Data from a School-Based Intervention Study

This study aimed to determine dietary practices and meal patterns among Malaysian overweight and obese school children at baseline. This study was part of a school-based obesity intervention study, My Body is Fit and Fabulous at School (MyBFF@school). It involved 1045 primary and 1041 secondary overweight and obese school children from a randomly selected 23 out of 1196 primary and 15 out of 416 secondary government schools in central Peninsular Malaysia. The results showed a significantly higher of adequate intake (4-8 servings/day) of cereals and grains among primary (54.7%) than secondary school children (48.2%). About 28.2% of primary and 32.6% of secondary school children had consumed adequate fruit (2 servings/day), while a very low percentage of both primary (5.0%) and secondary (3.6%) school children consumed adequate vegetables (3 servings/day). As for the meal patterns, school children in both primary and secondary were not taking breakfast regularly (mean±SD for primary: 3.16 ± 2.61 days/week vs secondary: 2.97 ± 2.52 days/week). There was also a significantly higher mean frequency of primary school children brought plain water to school than the secondary school children. In conclusion, urgent actions to address improper dietary practices and meal patterns of overweight and obese school children in Malaysia are warranted.

Combined effects of knee brace, laterally wedged insoles, and toe-out gait on knee adduction moment and fall risk in moderate medial knee osteoarthritis patients

BACKGROUND:

Knee osteoarthritis is a major contributor to the global burden of disease. There is a need of reducing knee joint load and to improve balance and physical function among knee osteoarthritis patients.

OBJECTIVES:

To test the hypothesis that toe-out gait will reduce second peak knee adduction moment further and increase fall risk when combined with knee brace and laterally wedged insole in knee osteoarthritis patients.

STUDY DESIGN:

Single visit study with repeated measures.

METHODS:

First and second peak knee adduction moments, fall risk and comfort level. First and second peak knee adduction moments were determined from three-dimensional gait analysis, completed under six randomized conditions: (1) natural, (2) knee brace, (3) knee brace + toe-out gait, (4) laterally wedged insole, (5) laterally wedged insole + toe-out gait, and (6) knee brace + laterally wedged insole + toe-out gait. Fall risk was assessed by Biodex Balance System using three randomized stability settings: (1) static, (2) moderate dynamic setting (FR12), and (3) high dynamic setting (FR8).

RESULTS:

The reduction in first peak knee adduction moment and second peak knee adduction moment was greatest (7.16% and 25.55%, respectively) when toe-out gait combine with knee brace and laterally wedged insole. Significant increase in fall risk was observed with knee brace + laterally wedged insole + toe-out gait (42.85%) at FR12. Similar significant balance reductions were found at FR8 condition for knee brace + toe-out gait (35.71%), laterally wedged insole + toe-out gait (28.57%), and knee brace + laterally wedged insole + toe-out gait (50%) as compared to natural. However, knee brace decreased fall risk at FR12 by 28.57%.

CONCLUSION:

There is a synergistic effect of toe-out when combined with knee brace and laterally wedged insole concurrently in second peak knee adduction moment reduction but with a greater degree of fall risk. Simultaneous use of conservative treatments also decreases comfort level.

CLINICAL RELEVANCE

Patients with mild and moderate knee osteoarthritis are usually prescribed conservative treatment techniques. This study will provide an insight whether or not a combination of these techniques have a synergistic effect in reducing knee joint load.

TG : HDL-C Ratio Is a Good Marker to Identify Children Affected by Obesity with Increased Cardiometabolic Risk and Insulin Resistance

Metabolic syndrome (MetS) is an important predictor of cardiovascular diseases in adulthood. This study aims to examine the clinical utility of triglyceride to high-density lipoprotein ratio (TG : HDL-C) in identifying cardiometabolic risk and insulin resistance (IR) among children with obesity, in comparison with MetS as defined by the International Diabetes Federation (IDF). Data of 232 children with obesity aged 10-16 years were obtained from our study, MyBFF@school study, conducted between January and December 2014. Children were divided into tertiles of TG : HDL-C ratio. The minimum value of the highest tertile was 1.11. Thus, elevated TG : HDL-C ratio was defined as TG : HDL-C ≥1.11. Children with MetS were categorized based on the definition established by the IDF. Out of 232 children, 23 (9.9%) had MetS, out of which 5.6% were boys. Almost twofold of boys and girls had elevated TG : HDL-C ratio compared to MetS: 13.8% vs. 5.6% and 13.8% vs. 4.3%, respectively. Children with elevated TG : HDL-C ratio had lower fasting glucose compared to children with MetS (boys = 5.15 ± 0.4 vs. 6.34 ± 2.85 mmol/l, p=0.02; girls = 5.17 ± 0.28 vs. 6.8 ± 4.3 mmol/l, p=0.03). Additionally, boys with elevated TG : HDL-C ratio had a higher HDL-C level compared to those with MetS (1.08 ± 0.18 vs. 0.96 ± 0.1 mmol/l, p=0.03). There was no significant difference across other MetS-associated risk factors. Overall, TG : HDL-C ratio demonstrated higher sensitivity (42.7% vs. 12.9%) but lower specificity (74.8% vs. 93.2%) than MetS in identifying IR, either in HOMA-IR ≥2.6 for prepubertal children or HOMA-IR ≥4 for pubertal children. TG : HDL-C ratio in children with obesity is thus as useful as the diagnosis of MetS. It should be considered an additional component to MetS, especially as a surrogate marker for IR.

Effects of different foot progression angles and platform settings on postural stability and fall risk in healthy and medial knee osteoarthritic adults

This study aims to investigate the effects of varying toe angles at different platform settings on Overall Stability Index of postural stability and fall risk using Biodex Balance System in healthy participants and medial knee osteoarthritis patients. Biodex Balance System was employed to measure postural stability and fall risk at different foot progression angles (ranging from -20° to 40°, with 10° increments) on 20 healthy (control group) and 20 knee osteoarthritis patients (osteoarthritis group) randomly (age: 59.50 ± 7.33 years and 61.50 ± 8.63 years; body mass: 69.95 ± 9.86 kg and 70.45 ± 8.80 kg). Platform settings used were (1) static, (2) postural stability dynamic level 8 (PS8), (3) fall risk levels 12 to 8 (FR12) and (4) fall risk levels 8 to 2 (FR8). Data from the tests were analysed using three-way mixed repeated measures analysis of variance. The participant group, platform settings and toe angles all had a significant main effect on balance ( p ≤ 0.02). Platform settings had a significant interaction effect with participant group F(3, 144) = 6.97, p < 0.01 and toe angles F(21, 798) = 2.83, p < 0.01. Non-significant interactions were found for group × toe angles, F(7, 266) = 0.89, p = 0.50, and for group × toe angles × settings, F(21, 798) = 1.07, p = 0.36. The medial knee osteoarthritis group has a poorer postural stability and increased fall risk as compared to the healthy group. Changing platform settings has a more pronounced effect on balance in knee osteoarthritis group than in healthy participants. Changing toe angles produced similar effects in both the participant groups, with decreased stability and increased fall risk at extreme toe-in and toe-out angles.

Pre-participation evaluation of Malaysian university athletes – the importance of cardiovascular screening

Background: Sudden cardiac arrest and death (SCA/D) remains the leading cause of mortality among athletes. Contemporary standards of identifying normal physiological cardiac adaptations and remodeling from regular athletic training based on certain ECG morphology have been clearly defined by the ‘Seattle Criteria’ in 2012, with an updated ‘International Consensus’ in 2017. In heterogenous Asia, regional SCA/D preponderance data is still lacking. This study aims to report on the detection of potentially dangerous cardiovascular conditions in Malaysian university athletes via pre-participation evaluation.Methods: 176 Malaysian athletes competing in the 18th ASEAN University Games 2016 were requested to attend a centralised pre-participation evaluation (PPE) prior to the games. The PPE included history, physical examination and a resting ECG. Participating sports and the corresponding number of athletes were athletics (40), basketball (26), football (24), silat (16), rugby (14), badminton (14), table tennis (12), shooting (12), fencing (10) and petanque (8).Results: 113 athletes (64.2%) attended and completed the PPE. The highest percentages of athletes screened were from shooting, fencing and petanque (100% respectively), whilst the lowest were from the basketball team (23.1%).  Three abnormal ECGs were identified: a multiple premature ventricular contractions, an atrial tachyarrhythmia and a ventricular pre-excitation. These three athletes were referred for subsequent investigations of which two were allowed to return to play. The latter athlete was diagnosed with Wolff-Parkinson-White syndrome and was advised against competing until definitive management was instituted.  Conclusion: Only a fair number of Malaysian university athletes completed the medical screening, and hence are possibly unaware of the importance of PPE. Despite our small sample size, we picked up three cases requiring further investigation and interventional studies. No screening program provides absolute protection against death. Thus, more evidence-based research and constant update in best practice guidelines are vital to foster safe sports participation and ultimately reduce incidence of SCA/D in the athletic population. Athletes need to be aware and give full cooperation for PPE to ensure timely detection of high risk cardiovascular conditions especially those related to sudden death in sports.

Triglyceride to HDL-C Ratio is Associated with Insulin Resistance in Overweight and Obese Children

The purpose of this study was to investigate the usefulness of triglyceride to hdl-c ratio (TG:HDL-C) as an insulin resistance (IR) marker for overweight and obese children. A total of 271 blood samples of obese and overweight children aged 9-16 years were analysed for fasting glucose, lipids and insulin. Children were divided into IR and non-insulin resistance, using homeostasis model assessment (HOMA). The children were then stratified by tertiles of TG: HDL-C ratio. The strength between TG:HDL-C ratio and other parameters of IR were quantified using Pearson correlation coefficient (r). Odds ratio was estimated using multiple logistic regression adjusted for age, gender, pubertal stages and IR potential risk factors. Children with IR had significantly higher TG:HDL-C ratio (2.48) (p = 0.01). TG:HDL-C ratio was significantly correlated with HOMA-IR (r = 0.104, p < 0.005) and waist circumference (r = 0.134, p < 0.001). Increasing tertiles of TG:HDL-C ratio showed significant increase in mean insulin level (p = 0.03), HOMA-IR (p = 0.04) and significantly higher number of children with acanthosis nigricans and metabolic syndrome. The odds of having IR was about 2.5 times higher (OR = 2.47; 95% CI 1.23, 4.95; p = 0.01) for those in the highest tertiles of TG:HDL-C ratio. Hence, TG:HDL-C may be a useful tool to identify high risk individuals.

In vivo and in vitro evaluation of the effects of Urtica dioica and swimming activity on diabetic factors and pancreatic beta cells

BACKGROUND

Urtica dioica (UD) has been identified as a traditional herbal medicine. This study aimed to investigate the effect of UD extract and swimming activity on diabetic parameters through in vivo and in vitro experiments.

METHODS

Adult WKY male rats were randomly distributed in nine groups: intact control, diabetic control, diabetic + 625 mg/kg, 1.25 g/kg UD, diabetic + 100 mg/kg Metformin, diabetic + swimming, diabetic + swimming 625 mg/kg, 1.25 g/kg UD, and diabetic +100 mg/kg Metformin + swimming. The hearts of the animals were punctured, and blood samples were collected for biochemical analysis. The entire pancreas was exposed for histologic examination. The effect of UD on insulin secretion by RIN-5F cells in 6.25 or 12.5 mM glucose dose was examined. Glucose uptake by cultured L6 myotubes was determined.

RESULTS

The serum glucose concentration decreased, the insulin resistance and insulin sensitivity significantly increased in treated groups. These changes were more pronounced in the group that received UD extract and swimming training. Regeneration and less beta cell damage of Langerhans islets were observed in the treated groups. UD treatment increased insulin secretion in the RIN-5F cells and glucose uptake in the L6 myotubes cells.

CONCLUSIONS

Swimming exercises accompanied by consuming UD aqueous extracts effectively improved diabetic parameters, repaired pancreatic tissues in streptozotocin-induced diabetics in vivo, and increased glucose uptake or insulin in UD-treated cells in vitro.

Cognitive Appraisals and Lived Experiences During Injury Rehabilitation: A Narrative Account Within Personal and Situational Backdrop

Background:

The article highlights an athlete’s cognitive appraisals form the onset to return to play. The narrative provides how an athlete constructs a sense of self within personal and situational factors and describes the subjective experiences during rehabilitation

Objectives:

The study examined the cognitive appraisal and psychological response within the backdrop of personal and situational factors in an injured athlete.

Patients and Methods:

The study is contextualized within the injury rehabilitation experiences of a cycling national athlete aged about 18 years old who was presented with the complaint of right shoulder pain, following a right shoulder dislocation. The 22 page narrative account provided by the athlete offered a holistic and integrated account of his experiences from the onset to return to play. A six step narrative analysis was analyzed by two qualified psychologists and two medical practitioners.

Results:

The themes are extracted to understand what was important to the participant. The cognitive appraisal and lived experiences are discussed within three dominant themes: 1) Injury and consequences in sporting life. 2) Childhood experiences, emotions, social support. 3) Trusting relationship, behavioral outcome and hopeful future. The study indicates the influence of personal and situational factors in cognitive appraisals leading to emotional and behavioral responses during rehabilitation.

Conclusions:

The study demonstrates how individual experiences become a dynamic core of psychological response during injury rehabilitation. The study highlights the cognitive appraisals and, emotional upheaval to provide an understanding of how personal and situational factors affect the psychological responses of an injured athlete. Findings suggest the need to develop a holistic approach as an effective strategy in injury rehabilitation.

Balance and risk of fall in individuals with bilateral mild and moderate knee osteoarthritis

Balance is essential for mobility and performing activities of daily living. People with knee osteoarthritis display impairment in knee joint proprioception. Thus, the aim of this study was to evaluate balance and risk of fall in individuals with bilateral mild and moderate knee osteoarthritis. Sixty subjects aged between 50 and 70 years volunteered in this study. They were categorized into three groups which were healthy (n = 20), mild (n = 20) and moderate (n = 20) bilateral knee osteoarthritis groups. Dynamic and static balance and risk of fall were assessed using Biodex Stability System. In addition, Timed Up and Go test was used as a clinical test for balance. Results of this study illustrated that there were significant differences in balance (dynamic and static) and risk of fall between three groups. In addition, the main (most significant) difference was found to be between healthy group and moderate group. Furthermore, on clinical scoring of balance, the “Timed Up and Go” test, all three groups showed significant difference. In conclusion, bilateral knee osteoarthritis impaired the balance and increased the risk of fall, particularly in people with moderate knee osteoarthritis.

Effects of the 11+ and Harmoknee Warm-up Programs on Physical Performance Measures in Professional Soccer Players

The purpose of this study was to examine the effects of the 11+ and HarmoKnee warm-up programs on performance measures in professional soccer players. Thirty-six male professional soccer players (age: 18.9 ± 1.4 years) were divided into 3 groups, the 11+, HarmoKnee and control group (n = 12 per group). The experimental groups performed the programs 3 times per week for 2 months (24 sessions), whereas the control group only performed their regular soccer training. The performance tests carried out were: 10m speed tests with and without a ball, 20m single sprint, vertical jump, Wall-Volley and Illinois agility tests. The 11+ group demonstrated significant increases from pre-to-post time points in the vertical jump (3.7%), Wall- Volley (5.4%) and Illinois agility tests (1.7%), while the HarmoKnee group showed a significant increase in Wall-Volley test, with a 5.2% increase. The repeated measures analysis revealed differences between the groups (large effect size) in the 11+ and HarmoKnee groups, compared to the control group, in 10m speed tests with and without a ball, 20m single sprint and Illinois agility tests (p < 0.05). Thus 8-weeks performing the 11+ warm-up program can enhance jump height, agility and soccer skill while the HarmoKnee program generally only improves soccer skill in young professional male soccer players. Key PointsThe 11+ improves performance by means of Illinois agility, vertical jump and Wall-Volley tests whereas HarmoKnee improves Wall-Volley test. Incorporating 11+ as a part of the warm-up program by the young teams would be beneficial in agility, leg power and soccer skill respectively.Further modification of both programs may be required to fully realize the players' speed performance potential.Data from this research can be helpful for soccer trainers in choosing programs to enhance performances in young male professional soccer players.

Badminton injuries in youth competitive players

AIM

The aim of the study was to examine sports injury pattern and establish cost of injuries in relation to training of 58 competitive badminton players in a Malaysian National Sports School.

METHODS

This one-year prospective observational study recruited all the 13-16 year old students after obtaining informed consent from their appointed guardian. All participants were requested to report any injuries, which were pain or disabilities that occur within the study period (September 1, 2008 to August 31, 2009) either during training or competition. Injured students were to seek treatment from the researcher(s) who made weekly visits and they were then followed up accordingly until they return to full training. Details and progress of the injuries were documented during each visit.

RESULTS

Sixty-three injuries were recorded. Soft tissue sprains/strains were the commonest injury (64%). About one third of the injuries occurred in the lower limb especially the knees and was followed by back injuries; 38% of the injuries did not require training modification, half of these injuries resumed training within one week. Upon full training, half of them were still symptomatic. Injury risk was 57%; injury rate was 0.9 injuries/ player/1000 training hours.

CONCLUSION

Badminton injuries mostly involved the lower limb and almost all overuse injuries occurred in the lower limb. However, badminton injuries as a whole were predominantly sprains and strains, and not overuse in nature as widely believed.

The effects of comprehensive warm-up programs on proprioception, static and dynamic balance on male soccer players

PURPOSE

The study investigated the effects of FIFA 11+ and HarmoKnee, both being popular warm-up programs, on proprioception, and on the static and dynamic balance of professional male soccer players.

METHODS

Under 21 year-old soccer players (n = 36) were divided randomly into 11+, HarmoKnee and control groups. The programs were performed for 2 months (24 sessions). Proprioception was measured bilaterally at 30°, 45° and 60° knee flexion using the Biodex Isokinetic Dynamometer. Static and dynamic balances were evaluated using the stork stand test and Star Excursion Balance Test (SEBT), respectively.

RESULTS

The proprioception error of dominant leg significantly decreased from pre- to post-test by 2.8% and 1.7% in the 11+ group at 45° and 60° knee flexion, compared to 3% and 2.1% in the HarmoKnee group. The largest joint positioning error was in the non-dominant leg at 30° knee flexion (mean error value = 5.047), (p<0.05). The static balance with the eyes opened increased in the 11+ by 10.9% and in the HarmoKnee by 6.1% (p<0.05). The static balance with eyes closed significantly increased in the 11+ by 12.4% and in the HarmoKnee by 17.6%. The results indicated that static balance was significantly higher in eyes opened compared to eyes closed (p = 0.000). Significant improvements in SEBT in the 11+ (12.4%) and HarmoKnee (17.6%) groups were also found.

CONCLUSION

Both the 11+ and HarmoKnee programs were proven to be useful warm-up protocols in improving proprioception at 45° and 60° knee flexion as well as static and dynamic balance in professional male soccer players. Data from this research may be helpful in encouraging coaches or trainers to implement the two warm-up programs in their soccer teams.

The effects of injury preventive warm-up programs on knee strength ratio in young male professional soccer players

PURPOSE

We aimed to investigate the effect of FIFA 11+ (11+) and HarmoKnee injury preventive warm-up programs on conventional strength ratio (CSR), dynamic control ratio (DCR) and fast/slow speed ratio (FSR) in young male professional soccer players. These ratios are related to the risk of injury to the knee in soccer players.

METHODS

Thirty-six players were divided into 3 groups; FIFA 11+, HarmoKnee and control (n = 12 per group). These exercises were performed 3 times per week for 2 months (24 sessions). The CSR, DCR and FSR were measured before and after the intervention.

RESULTS

After training, the CSR and DCR of knee muscles in both groups were found to be lower than the published normal values (0.61, 0.72, and 0.78 during 60°.s(-1), 180°.s(-1) and 300°.s(-1), respectively). The CSR (60°.s(-1)) increased by 8% and FSR in the quadriceps of the non-dominant leg by 8% in the 11+. Meanwhile, the DCR in the dominant and non-dominant legs were reduced by 40% and 30% respectively in the 11+. The CSR (60°.s(-1)) in the non-dominant leg showed significant differences between the 11+, HarmoKnee and control groups (p = 0.02). As for the DCR analysis between groups, there were significant differences in the non-dominant leg between both programs with the control group (p = 0.04). For FSR no significant changes were found between groups.

CONCLUSIONS

It can be concluded that the 11+ improved CSR and FSR, but the HarmoKnee program did not demonstrate improvement. We suggest adding more training elements to the HarmoKnee program that aimed to enhance hamstring strength (CSR, DCR and FSR). Professional soccer players have higher predisposition of getting knee injuries because hamstring to quadriceps ratio were found to be lower than the average values. It seems that the 11+ have potentials to improve CSR and FSR as well as prevent knee injuries in soccer players.

Muscle strength and damage following two modes of variable resistance training

Nautilus Machine (NM) and Elastic Resistance (ER) have gained considerable popularity among athletes and recreational lifters seeking to increase muscle strength. However, there is controversy concerning the use of ER for increasing muscle hypertrophy and strength among healthy-trained individuals. The aim of the study was to compare the effect of repeated near maximal contractions by ER/NM on indicators of muscle damage including: maximal strength decrement (MVIC), rate of muscle soreness (DOMS), concentration of plasma creatine kinase (CK) and increased high muscle signal on T2 weighted images using magnetic resonance imaging (MRI). Nine healthy male subjects completed two modalities of exercise (5 sets × 10RM ER/NM) in a counterbalance cross-over study design with three weeks "wash-out" period between experiments. The MVIC was measured and DOMS rated and recorded for 4 consecutive days while blood samples were collected on day 1, 3, 5 and 7. Prior to and forty eight hours after completion of each mode of exercise, subjects underwent MRI scanning. The average of applied forces demonstrated significantly higher value for NM compared with ER (362 ± 34.2 N vs 266.73 ± 44.6 N respectively) throughout the 5 sets of dynamic exercise (all p < 0.05). However, the indicators of muscle damage (T2 relaxation time, DOMS, MVIC and serum CK) exhibited a very similar response across both modes of training. Plasma CK increased significantly following both modes of training with the peak value on Day 3 (p < 0.05). The time course of muscle soreness reached a significant level after both modes of exercise and showed a peak value on the 2(nd) day (p < 0.05). The T2 relaxation time demonstrated a statistically significant increase following ER and NM compared with the pre-test value (p < 0.05). The similarity of these responses following both the ER and NM exercise training session suggests that both modes of training provide a similar training stress; despite a considerably lower external force generation during ER. The importance of these findings is underlined by the fact that exercise-induced muscle damage has been shown to be the underlying mechanism of further muscle hypertrophy. Key pointsExercise induced muscle soreness increased levels of plasma CK, increased MRI T2 signal and prolonged strength loss indicate the moderate to intense nature of the training protocol.The similarity of these responses following both the Elastic Resistance and Nautilus Machine exercise training session suggests that both modes of training provide a similar training stress; despite a considerably lower external force generation during ER.The data in the present study suggest elastic training is a viable mode of resistance exercise that can provide a training stimulus greater than that employed in rehabilitation settings.

Prevention of tooth hypersensitivity caused by the hydrodynamic action of zinc phosphate and composite resin luting cements (SEM) study

This study was done to determine the role of cement liner as a reducing factor to the fluid movement in order to prevent tooth hypersensitivity according to the hydrodynamic theory during cementation of crowns. A total of fourty freshly extracted intact lower molar were selected for this study. After conventional tooth preparation the teeth were sub-divided into four equal groups to identify the role of cement liner in preventing the penetration of used cement into the dentinal tubules. Scanning electron microscopic study proved the efficiency of glass ionomer liner on preventing cement penetration into the dentinal tubules.

An energy dispersive X-ray micro-analysis (EDX) interfacial study on a high copper amalgam/polycarboxylate cement combination

The interface between a polycarboxylate cement and a high copper amalgam core containing (21%) tin by weight was analyzed by EDX. It was found that, the tin concentration at the interface was very low (1.26%). On the other hand, a higher copper concentration was demonstrated (6.39%). Mean while a correlation was established between the tin concentration of the amalgam core and the shear bond strength with polycarboxylate cement. Moreover, it could be assumed that, the tin concentration rather than the copper concentration of the amalgam cores has the substantial effect on the shear bond strength between amalgam cores and polycarboxylate cement.