Effects of Short-term Repeated Sprint Exercise Training and Moderate Intensity Continuous Exercise Training on Vascular Function in Healthy Young Adults / 대한스포츠의학회지

Purpose@#Moderate-intensity continuous training (MICT) improves exercise capacity with vascular benefits, but time constraints hinder consistent adherence. High-intensity interval training (HIIT) has emerged as a time-efficient alternative, with repeated sprint training (RST) being the shortest format. We hypothesized that RST would be as effective as MICT in improving vascular function and exercise capacity in young adults. @*Methods@#Twenty-three adults (mean age, 26.2±3.8 years) were randomly assigned to either RST or MICT. RST involved 20 sets of 4-second cycling sprints followed by 30-second active recovery, totaling 11 minutes. MICT consisted of 30-minute cycling at 50% to 60% of heart rate reserve. Vascular function evaluated via brachial artery flow-mediated dilation. Exercise capacity (maximum oxygen uptake, total exercise load test time) and anaerobic capacity (maximum power, anaerobic threshold) were measured using maximum exercise tests. These variables were measured befre and after a 6-week training. @*Results@#Both groups showed comparable improvements in flow-mediated dilation (p＜ 0.05). Maximum oxygen intake slightly improved, while total exercise time significantly increased for both (p＜ 0.05). Anaerobic threshold unchanged, while maximum power improved (p＜ 0.05). @*Conclusion@#These findings underscore that RST is a time-efficient exercise strategy, which improves vascular function and exercise capacity as effectively as MICT in young adults.

Effects of Isometric Handgrip Exercise on Carotid Arterial Function and Cardiovascular Vasoreactivity Response to Sympathetic Stress in Young Adults / 대한스포츠의학회지

Purpose@#Isometric handgrip exercise (IHE) has a favorable cardiovascular effect and improves hemodynamic responses. Whether IHE attenuates stress-related hemodynamic reactivity assessed during a sympathetic challenge remains unexplored. We tested the hypothesis that an acute bout of IHE would improve carotid arterial function and attenuate cardiovascular vasoreactivity response to sympathetic stress in healthy adults. @*Methods@#In a randomized cross-over design, sixteen healthy adults (aged 21.8±3.1 years) were enrolled. Participants completed two testing sessions, separated by 1 week. Trials were either a control trial or performed IHE for two sets of 2 minutes at 30% of maximal voluntary contraction for each hand. The participant’s hand was immersed in an ice water bath (4 ℃ ) up to the wrist for 2 minutes. Carotid artery diameter, β-stiffness index, and compliance using ultrasound machine and brachial blood pressure (BP), heart rate (HR) were measured as indices of vasoreactivity at baseline, during, and recovery from cold pressor testing (CPT). @*Results@#The BP, HR, carotid artery diameter, and β-stiffness index increased similarly during CPT in both trials (p＜ 0.001), without any interaction effect. Compared with the IHE trial, arterial compliance decreased in the control groups at 120 seconds during recovery with a significant interaction effect (p=0.02). @*Conclusion@#These findings suggest that an acute IHE did not attenuate BP, HR, carotid artery diameter and β-stiffness index vasoreactivity, but improved carotid artery compliance to sympathetic activation in healthy young adults.

Acute Effects of Virtual Reality Exergame on Vascular Function in Children and Adolescents with Congenital Heart Disease: A Single-Arm Trial / 대한스포츠의학회지

Purpose@#Regular aerobic exercise improves exercise capacity and quality of life in children with congenital heart disease (CHD), but it remains unclear whether aerobic exercise would improve vascular function in children with CHD. We tested the hypothesis that acute bout of virtual reality (VR) exergame would improve vascular function in children with CHD. @*Methods@#In a single-arm study, eight children (age, 9±1 years; five males) with CHD participated in VR exergame (30 minutes at 40% of heart rate reserve) using a stationary cycle ergometer with a head mount display. Endothelial function and arterial stiffness as surrogate markers of vascular function were assessed via reactive hyperemia index (RHI) and augmentation index (AIx) using peripheral arterial tonometry at baseline and 30 minutes after VR exergame. @*Results@#Compared to baseline, VR exergame improved in RHI (1.08 [0.96–1.30] to 1.16 [1.09–1.36], p＜ 0.05) and natural log transformed RHI (0.07 [−0.04–0.26] to 0.15 [0.09–0.31], p＜ 0.05). However, no significant changes were observed for decrease AIx (−1.00 [−9.00–9.50] to −7.00 [−14.00–8.75], p=0.547) and AIx@75 (−6.50 [9.75–3.50] to −4.50 [−13.00–4.50], p=0.735) (all index values are reported as median [interquartile range]). @*Conclusion@#These findings suggest that a single bout of VR exergame has the potential to improve vascular endothelial function in children with CHD.

The Effect of Intermittent Resistance Activity for Interrupting Prolonged Sitting on Vascular Function and Postprandial Metabolism after a High-fat Meal / 대한스포츠의학회지

Purpose@#Numerous studies have reported the effects of interrupting prolonged sitting with aerobic exercise on vascular and postprandial function, but the effects of resistance exercise for interrupting prolonged sitting remain unclear. We tested the hypothesis that intermittent resistance activity breaks would attenuate prolonged sittinginduced vascular and postprandial metabolic dysfunction. @*Methods@#Fourteen healthy adults (age, 24±2 years; body mass index, 22.0±2.4 kg/m2 ) completed two trials in a randomized cross-over design. During a 4-hour sitting after a high-fat meal, the participants underwent either resistance activity (RA) with 10 repetitions of five exercises every hour or uninterrupted sitting as a control trial (SIT). Plasma glucose, triglycerides, and brachial artery blood pressure, along with blood flow and shear rate in the superficial femoral artery and carotid artery were measured at baseline and every hour during the 4-hour sitting period. Brachial artery flow-mediated dilation (FMD) was measured at baseline, 2 hours, and 4 hours after the start of the sitting. @*Results@#Plasma glucose and triglycerides increased after a high-fat meal in both RA and SIT groups without a significant interaction effect. In addition, while SIT group decreased brachial artery FMD (7.2%±2.0% to 6.5%±2.7% to 5.1%±2.6%), RA did not attenuate a decrease in FMD (7.6%±3.4% to 7.3%±3.1% to 6.7%±2.7%, interaction p=0.581). @*Conclusion@#Our findings indicate that interrupting prolonged sitting with intermittent RA did not attenuate the negative effects of sitting on vascular function and postprandial metabolism in young healthy adults.

The Emerging Role of Exercise and Optimal Exercise Prescription for Improving the Symptoms of Long COVID / 대한스포츠의학회지

Long COVID has emerged as a global medical challenge, characterized by persistent symptoms such as fatigue, dyspnea, and exercise intolerance following a coronavirus disease 19 (COVID-19) infection. The protracted nature of these symptoms necessitates the development of effective therapeutic approaches to alleviate the burden on individuals’ well-being and the healthcare system at large. While current pharmacological interventions offer limited efficacy, the exploration of alternative strategies becomes imperative. Exercise training has demonstrated promise in ameliorating long COVID symptoms, yet consensus regarding the optimal exercise modalities remains elusive. In light of this, the present review aims to elucidate the impact of exercise on long COVID symptoms and shed light on exercise prescriptions that have exhibited proven efficacy in the treatment and management of this syndrome.

Effects of Ischemic Preconditioning on Lower Limb Isokinetic Muscle Function and Blood Lactate Concentration in College Baseball Players / 대한스포츠의학회지

Purpose@#The purpose of this study was to determine whether ischemic preconditioning (IPC) improves lower limb isokinetic muscle function and blood lactate concentration. @*Methods@#In a randomized, crossover study, 10 men, college baseball players, performed knee extension and flexion using an isokinetic dynamometer, preceded by either IPC of the right lower limb (3 repetitions of 2 minutes occlusion and 5 minutes reperfusion at 180 mm Hg) or a control intervention (at 20 mm Hg). Blood lactate concentration was examined from rest to recovery after exercise. @*Results@#We found IPC possibly increased peak force and average power, but there is no significant difference.Also, blood lactate concentration was certainly lower at 3 minutes of recovery after IPC (p＜ 0.05) but there is no interaction effect. @*Conclusion@#As a result, IPC does not have any positive effects on isokinetic muscle function and blood lactate concentration of college baseball players.

Association between Physical Activity and Chronotropic Incompetence in Patients with Complex Congenital Heart Disease / 대한스포츠의학회지

Purpose@#Although chronotropic incompetence (CI) is common in patients with complex congenital heart disease (CHD) and is associated with adverse cardiovascular outcomes, few data are available regarding modifiable predictors of CI in this escalating patient population. We tested the hypothesis that higher levels of physical activity (PA) are associated with a lower prevalence of CI in patients with complex CHD and evaluated the receiver operating characteristic curve to identify the PA level that best predicted CI. @*Methods@#We evaluated 111 adolescents with complex CHD. CI was defined as the failure to achieve 80% of the chronotropic response index during peak cardiopulmonary exercise test. Self-reported habitual activity was obtained using a global PA questionnaire. @*Results@#CI was identified in 45 of the 111 cases (40.5%). After adjusting for potential confounding variables, the high PA group demonstrated a lower odds ratio for having CI (odds ratios, 0.25; 95% confidence interval, 0.06‒0.99) compared with the low PA group. The most accurate cut-point for PA to predict the prevalence of CI was 15 metabolic equivalents (METs)-hours/week (areas under the curve, 0.71; 95% confidence interval, 0.61‒0.81; sensitivity, 71%; specificity, 69%). @*Conclusion@#Our findings demonstrate that higher levels of PA are associated with a lower prevalence of CI, independent of potential confounders, and that 15 METs-hours/week of PA provides a cut-point for accurately predicting the presence of CI in adolescents with complex CHD.

Acute Effects of Postexercise Cigarette Smoking on Central Hemodynamics and Endothelial Function in Young Men / 대한스포츠의학회지

Purpose@#Recovery from exercise is a vulnerable phase that has been linked to increased susceptibility to sudden cardiovascular events. Cigarette smoking increases the risk of cardiovascular mortality and morbidity. We tested the hypothesis that postexercise cigarette smoking would attenuate hemodynamics and vascular function during recovery from exercise in young men. @*Methods@#Thirteen habitual smokers (age, 22±3 years; body mass index, 25.1±3.6 kg/m 2 ) participated in (1) cigarette smoking (0.6 mg nicotine) and (2) sham smoking (SHAM) immediately postexercise (30 minutes on a treadmill;40% to 60% of heart rate [HR] reserve) in a randomized order. Assessments were hemodynamics (HR, rate-pressure product [RPP], brachial and central artery blood pressures) and vascular function (arterial stiffness via carotid-femoral pulse wave velocity [PWV]; conduit vessel function via brachial artery flow-mediated dilation [FMD]). All variables were assessed at baseline, 10 minutes, and 30 minutes postexercise, except for FMD (baseline and 30 minutes postexercise). @*Results@#Compared with the SHAM trial, cigarette smoking increased HR, RPP, and brachial and central blood pressures postexercise (interaction, p＜ 0.05). PWV reduced and FMD increased postexercise in the SHAM trial, while cigarette smoking attenuated exercise-induced improvements (interaction, p＜ 0.05). @*Conclusion@#Cigarette smoking attenuated hemodynamic recovery and an improvement in arterial stiffness and conduit vessel function in young habitual smokers, thereby providing evidence for the negative effects of cigarette smoking during recovery from exercise.

A Comparison of Physical Activity and Exercise Capacity in Adults with Congenital Heart Disease and Healthy Controls / 대한스포츠의학회지

Purpose@#Advancements in surgical and nonsurgical care for congenital heart disease (CHD) have enabled an increase in survival into adulthood of these children with CHD, thereby contributing to the growth of the aging population, it is important to evaluate these functional outcome measures in adults with CHD. Therefore, this study aimed to compare the subjective and objective assessments of physical activity (PA) and exercise capacity (EC) in adults with CHD and age-matched, healthy controls. @*Methods@#Forty-six adults with CHD (male, 26; age, 20.6±1.3 years) and forty-six healthy controls (male, 24; age, 21.2±1.6 years) underwent an assessment of subjective and objective PA levels using the Global Physical Activity Questionnaire and the accelerometer device (GENEActiv) worn on the wrist for seven consecutive days, respectively.EC was directly measured by peak oxygen uptake (peak VO2 ) during a graded exercise test. @*Results@#Subjectively and objectively measured of moderate to vigorous PA in adults with CHD were lower than those with healthy controls (p=0.008, p=0.004), while the majority of adults with CHD have achieved the recommended levels of PA (150 min/wk). In addition, peak VO2 was lower in adults with CHD than in healthy controls (30.8±8 mL/kg/min vs. 46.7±10 mL/kg/min, p＜ 0.001). @*Conclusion@#Although the majority of adults with CHD meet the recommended levels of PA, their overall PA levels and EC are still lower than those of age-matched, healthy adults without CHD.

Comparison of Effects of Acute Tabata-Styled and Moderate Intensity Continuous Exercise on Vascular Function in Healthy Young Men / 대한스포츠의학회지

Purpose@#Regular moderate-intensity aerobic exercise confers immense vascular benefits, yet the lack of time remains the most common barrier to a regular exercise routine. A Tabata exercise is a type of high-intensity interval training exercise that is time efficient and has recently been demonstrated to improve cardiorespiratory fitness and metabolic profiles, but its benefits on vascular function still remain unclear. We tested the hypothesis that the Tabata-styled exercise would be as effective as moderate-intensity continuous exercise (MICE) in improving vascular function in young healthy adults. @*Methods@#Using a randomized, cross-over design, fourteen healthy men (age, 23.8±2.3 years; body mass index, 23.7±2.2 kg/m2 ) performed two acute exercise trials, separated at least by 72 hours: a modified Tabata-styled exercise (eight sets of 20-second exercise at 120% of maximal power output using a bike and 10-second rest, total 4 minutes) or a MICE for 30 minutes at a heart rate reserve of 40%–60%. Vascular function was assessed via brachial artery flow-mediated dilation and arterial stiffness (pulse wave velocity and augmentation index) at baseline and again at 60 minutes and 120 minutes after exercise. @*Results@#Compared with MICE, a Tabata-styled exercise increased heart rate at 60 minutes (p＜ 0.05). Both exercises improved vascular function to a similar extent, as evidenced by an increase in flow-mediated dilation and a reduction in arterial stiffness at 60 minutes and 120 minutes (p＜ 0.05). @*Conclusion@#These findings demonstrate that the Tabata-styled exercise is a time-efficient exercise strategy that is as effective as MICE in enhancing vascular function in healthy young men.

Effects of Isometric Handgrip Exercise versus Aerobic Exercise on Arterial Stiffness and Brachial Artery Flow-Mediated Dilation in Older Hypertensive Patients / 대한스포츠의학회지

PURPOSE: Isometric handgrip exercise (IHE) is an easy and accessible form of exercise that has beneficial effects on blood pressure (BP). However, it remains unclear whether IHE is similar benefits on arterial stiffness and endothelial function compared with aerobic exercise (AE) in elderly hypertensive patients. The aim of this study was to compare the effects of IHE versus AE on arterial stiffness and endothelial function in elderly hypertensive patients.METHODS: We conducted a randomized controlled trial with a three-arm design. Fifty-four elderly hypertensive patients (15 men; mean age, 69±6 years; systolic blood pressure, 131.2±14.7; diastolic blood pressure, 80.2±7.9 mm Hg) were randomized to IHE training (n=18), AE training (n=21), or non-exercise control group (n=21) for 12 weeks. Bilateral IHE training was performed four times of 2 minutes at 30% of maximal voluntary contraction with three times per week. AE training was performed brisk walking for 30 minutes at moderate intensity with three times per week. Carotid-femoral pulse wave velocity (PWV), augmentation index heart rate corrected (AIx@75 bpm) and brachial artery flow-mediated vasodilation (FMD) as indices of arterial stiffness and endothelial function were measured at baseline and after the intervention.RESULTS: Following 12-week intervention, resting BP was significantly decreased in both IHE (p=0.001) and AE groups (p=0.002). AIx@75 bpm and FMD were unchanged in the all groups. However, PWV was significantly decreased in both IHE and AE groups (IHE, 10.9±2.3 to 9.9±2.1 m/s [p<0.001]; AE, 10.5±2.0 to 9.4±1.6 m/s [p=0.001]), without any change in the control group.CONCLUSION: These findings suggest that both IHE and AE trainings were comparable effect in improving arterial stiffness in elderly hypertensive patients.

Effect of Remote Ischemic Preconditioning on Maximal Exercise Tolerance in Young Adults / 대한스포츠의학회지

PURPOSE: Remote ischemic preconditioning (RIPC), induced by repeated bouts of ischemia followed by reperfusion of the arm or leg is a noninvasive strategy to protect a target organ against oxidative stress and injury caused by ischemia and reperfusion. Interestingly, recent evidence suggests that RIPC may also improve exercise performance by increasing maximal oxygen consumption, but such finding remain equivocal. As such, the purpose of the study was to examine the effect of RIPC on exercise performance in healthy individuals. METHODS: In a randomized cross-over design, 17 healthy male participants (age, 23±3 years) were exposed to either a sham control (six cycles of 5 minutes bilateral thigh cuff occlusion at 20 mm Hg) or RIPC (six cycles of 5 minutes bilateral thigh cuff occlusion at 180 mm Hg) an hour before a maximal exercise test. We measured maximal oxygen consumption, power output, heat rate, blood pressure, and blood lactate as exercise performance parameters during a maximal exercise test performed on an upright bicycle. RESULTS: Compared with the sham control, RIPC improved maximal oxygen consumption (7.4%, p=0.025) and maximal power output (11.5%, p=0.010), whereas other exercise performance parameters remained unchanged with RIPC (p>0.05). CONCLUSION: Taken together, the improvements in maximal oxygen consumption and maximal power output induced by RIPC may suggest that RIPC should be considered as a method for improving exercise performance.

Effect of an Exergaming on Postprandial Endothelial Dysfunction Following a High Fat Meal in Individuals with Spinal Cord Injury / 대한스포츠의학회지

Endothelial dysfunction induced with a high-fat meal may be attenuated with an exercise in abled bodies individuals. Exergaming may be an exercise type applicable for disabled bodied individuals. We tested the hypothesis that an acute bout of exergaming following a high-fat meal would decrease postprandial lipemia, and endothelial dysfunction among individuals with spinal cord injury. Forty participants (age, 41±8 years; 24 males) were randomly assigned to either an exergaming group (n=20) or control group with seated rest (n=20) following a high-fat meal. Hemodynamic and blood parameters and flow-mediated vasodilation (FMD) as an index of endothelial function were measured at baseline and 4 hours after a high-fat meal. In half an hour following a high-fat meal, the exergaming group performed 50 minutes of moderate intensity active video games (Nintendo Wii Sports: boxing, tennis). Levels of blood triglycerides increased in both group (p<0.05) following high-fat meal. FMD significantly decreased in the control group (10.4%±4.9% to 7.9%±4.4%) but significantly increased in the exergaming group (10.9%±5.3% to 12.3%±5.3%), with a significant interaction (p=0.004). These results show that a high-fat meal causes endothelial dysfunction in persons with spinal cord injury, but endothelial dysfunction following a high-fat meal was attenuated by an acute bout of exergaming regardless of postprandial lipemia. Therefore, exergaming for individuals with spinal cord injury may have a cardioprotective effect from postprandial endothelial dysfunction induced with an exposure of a high-fat meal.

Association of Occupational Stress and Cardiorespiratory Fitness with Cardiovascular Disease Risk Factors in Office Workers / 대한스포츠의학회지

Occupational stress is associated with increased risk of cardiovascular disease (CVD), while cardiorespiratory fitness (CRF) is associated with decreased risk of CVD. We tested the hypothesis that high occupational stress would be associated with increased cardiovascular risk profiles, but CRF may attenuate this association. We conducted a cross-sectional analysis in 70 healthy office workers (male, 28; female, 42; mean age, 38±8 years). Occupational stress was assessed using a validated self-reported questionnaire. Total CVD risk score (sum of z-standardized residuals) was calculated by blood pressure, body mass index, lipid profiles and glucose. CRF was estimated by predicted equation during maximal treadmill exercise test. The results showed that an interpersonal conflict as an index of occupational stress was positively correlated with cardiovascular risk score (r=0.43, p0.05). Furthermore, Participants with high stress but high CRF had lower cardiovascular risk score than those with high stress but low CRF (p<0.05). In conclusion, occupational stress is associated with an increased CVD risk, but CRF attenuated this association in office worker with increased occupational stress.

Comparison of Physical Activity and Health-related Quality of Life in Adolescents with and without Congenital Heart Disease: A Propensity Matched Comparison / 대한스포츠의학회지

Physical activity and health-related quality of life (HRQOL) are associated with overall health outcomes in adolescents with congenital heart disease (CHD). The purpose of this study was to compare the levels of physical activity and HRQOL in adolescents with CHD and healthy controls. In addition, we compared these variables using a propensity score matching to reduce the confounding effects. Participants were divided into three groups with simple CHD (n=55), complex CHD (n=173), and healthy controls (n=181). Self-reported physical activity levels (metabolic equivalent of task [MET]-hr/wk) were obtained using the Global Physical Activity Questionnaire. HRQOL was evaluated using the Pediatric Quality of Life Inventory questionnaire. Total scores of HRQOL in adolescents with complex CHD were significantly lower than those with simple CHD (p=0.022) and healthy controls (p<0.001), respectively; however, there was no significant difference in total scores of HRQOL between adolescents with simple CHD and healthy controls. Levels of physical activity in adolescents with complex CHD were significantly lower than those with simple CHD (p=0.001) and healthy controls (p<0.001). After propensity matched analysis (44 pairs), the results were consistent with the above results. In conclusion, HRQOL scores and physical activity levels are significantly lower in adolescents with complex CHD, but not in adolescents with simple CHD, than in healthy adolescents.

Acute Resistance Exercise Attenuates the Cardiovascular Reactivity to Cold Pressor Test in Healthy Adults / 대한스포츠의학회지

Increased cardiovascular reactivity to sympathetic challenge is associated with increased risk of hypertension and cardiovascular disease. Acute aerobic exercise blunts stress related cardiovascular reactivity, but whether acute resistance exercise attenuates cardiovascular reactivity is unknown. We tested the hypothesis that acute resistance exercise will attenuate hemodynamic reactivity to a cold pressor test in healthy adults. Using a randomized cross-over trial, 20 healthy adults (9 males, 11 females; age, 26±5 years; body mass index, 23.85±3.19 kg/m2) completed two testing sessions, separated by 1 week. Sessions consisted of either a control condition or an acute resistance exercise prior to cold pressor testing (two sets, eight exercises, 40%-60% of 1 repetition maximum for upper and lower extremity). Blood pressure and heart rate measured at baseline, 30 seconds, and 120 seconds during a 3-minute cold pressor test (ice water, 4℃), and 30 seconds and 120 seconds post-cold pressor testing, respectively. During the cold pressor test, there were significant increases in blood pressures and heart rate (p<0.05) in both groups. However, acute resistance exercise attenuated increases in systolic blood pressure, but not heart rate, compared with the control (all p<0.05 for interact effects). These findings show that the cold pressor test significantly increases blood pressures and heart rate in healthy adults, but an acute bout of resistance exercise attenuated the hemodynamic response to the cold pressor test. Therefore, resistance exercise may have a favorable effect on cardiovascular reactivity to sympathetic activation in healthy adults.

The Effects of Acute Resistance Exercise on Ischemia-Reperfusion Injury-Induced Macro and Microvascular Dysfunction in Healthy Young Adults / 대한스포츠의학회지

Ischemia reperfusion injury (IRI) leads to a temporary decrease in macrovascular function, but whether IRI causes microvascular dysfunction is not known. Resistance exercise involves muscular contractions that can make downstream tissues ischemic and may ischemic preconditioning the vasculature against endothelial IRI. We tested the hypothesis that an acute resistance exercise prior to IRI would prevent or attenuate IRI induced macro- and microvascular dysfunction in healthy young adults. Nineteen healthy young subjects (age 22+/-2 years) were randomly assigned to either a resistance exercise group (n=10) as a model to produce ischemic preconditioning or a control group (n=9). The resistance exercise was performed eight types of systemic resistance exercise. Ischemia was induced by inflating a cuff placed around the upper arm to 200 mm Hg for 20 minutes. carotid-femoral pulse wave velocity (cfPWV) as index of macrovascular function and reactive hyperemia index (RHI) using by fingertip arterial tonometry as index of microvascular function were measured at baselines and 15 and 30 minutes after ischemia reperfusion injury. cfPWV was increased in control group but decreased in resistance exercise group following IRI. There was a significant interaction effect between resistance exercise group and control group for cfPWV (p=0.022). The RHI was unaffected following IRI and also unchanged by a resistance exercise. These findings show that ischemia reperfusion caused macrovascular dysfunction but not microvascular dysfunction. However, this macrovascular dysfunction following IRI was not shown in the resistance exercise group. Thus, an acute bout of resistance exercise prior to ischemia may prevent against ischemia reperfusion injury induced macrovascular dysfunction.

Effects of Acute Resistance Exercise on Arterial Stiffness in Young Men

BACKGROUND AND OBJECTIVES: Increased central arterial stiffness is an emerging risk factor for cardiovascular disease. Acute aerobic exercise reduces arterial stiffness, while acute resistance exercise may increase arterial stiffness, but this is not a universal finding. We tested whether an acute resistance exercise program was associated with an increase in arterial stiffness in healthy young men. SUBJECTS AND METHODS: Thirteen healthy subjects were studied under parallel experimental conditions on 2 separate days. The order of experiments was randomized between resistance exercise (8 resistance exercises at 60% of 1 repeated maximal) and sham control (seated rest in the exercise room). Carotid-femoral pulse wave velocity (PWV) and aortic augmentation index as indices of aortic stiffness were measured using applanation tonometry. Measurements were made at baseline before treatments, 20 minutes, and 40 minutes after treatments (resistance exercise and sham control). RESULTS: There was no difference in resting heart rate or in arterial stiffness between the two experimental conditions at baseline. At 20 minutes after resistance exercise, heart rate, carotid-femoral PWV and augmentation index@75(%) were significantly increased in the resistance exercise group compared with the sham control (p<0.05). Brachial blood pressure, central blood pressure and pulse pressure were not significantly increased after resistance exercise. CONCLUSION: An acute resistance exercise program can increase arterial stiffness in young healthy men. Further studies are needed to clarify the effects of long-term resistance training on arterial stiffness.

Effects of the Proprioceptive Exercises on Isokinetic Strength and Postural Control

OBJECTIVE: To investigate the effects of lower extremity proprioceptive training on postural control and strength of the knee and ankle muscles. METHOD: Twenty-two healthy subjects (age 27+/-4 yrs) were randomly assigned to a training (TRN, n=11) or a control (CTL, n=11) group. TRN group participated in the dominant leg proprioceptive training that was performed on a balance board and mini-trampoline without strength training for 6 weeks. All subjects were evaluated for leg muscle strength and postural sway using the isokinetic device and force platform before and after the training. Assessed parameters were 1) concentric and eccentric strength of knee flexor/ extensor and concentric strength of ankle plantar flexor/dorsiflexor and invertor/evertor 2) the standard deviation of the postural sway with eyes open or closed. RESULTS: Statistically significant improvements in both medial-lateral and anterior-posterior parameters of postural sway with eyes closed were observed after training in TRN group (p < 0.05) compared to CTL group. But no significant changes in any isokinetic strength parameters were observed after training in TRN group. CONCLUSION: The proprioceptive exercises that we used could improve one-leg balance without significant strength gain after 6 weeks training.

Effects of Cardiac Rehabilitation in Patients with Myocardial Infarction

BACKGROUND: Since the 1980s, early ambulation and cardiac rehabilitation have been emphasized in clincal practice after myocardial infarction. This is based on the belief that cardiac rehabilitation can reduce cardiovascular mortality, improve functional capacity and reduce the risk of further coronary events. In this study, we investigate the effect of aerobic exercise-based cardiac rehabilitation on functiona capacity and cardiopulmonary response in patiets with myocardial infarction. METHODS: 19 patients were divided into two group(9 patients for training group and 10 patients for control group) at 4-6 weeks after acute myocardial infarction. Training group performed aerobic exercise for 8 weeks(3 sessions per week, mean 53mins per session) at 40-60% of heart rate(HR) reserve, while control group did not. Before and after 8 weeks, all patients performed symptom-limited exercise test using modified Bruce protocol. Also, breath by breath respiratory gas analysis was carried out throughout exercise test. RESULTS: For body composition, body weight(-2.7%, p<0.001), body mass index(-2.5%, p<0.001) and %body fat(-2.6%, p<0.05) were decrease significantly in training group after 8 week cardiac rehabilitation. Resting HR(-13%, p<0.05) was reduced significantly in training group, but no significant change occured in resting blood pressure between the two groups. Maximal oxygen uptake(18%, p<0.01) and anaerobic threshold(21%, p<0.05) were increased significantly in training group after 8 week cardiac rehabilitation as compared with the control group. There was no significant change in maximal O(2)pulse between the two groups. Submaximal rate-pressure product(-17%, p<0.05) and submaximal rate of perceived exertion (-2.6, p<0.001) were decreased significantly in training group after 8 week cardiac rehabilitation as compared with the control group. CONCLUSIONS: Our findings indicate that cardiac rehabilitation results in the significant improvement of functional capacity and cardiopulmonary response in patients with myocardial infarction. Cardiac rehabilitation for patients with myocardial infarction can contribute early return and readaptation to normal life, because myocardial oxygen consumption(or rate-pressure product) is decreased at the same exercise level after exercise training.