• Journal of Nutrition and Health
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• v.32 no.8
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• pp.870-876
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• 1999

The relationship between exercise intensity, oxidative stress and antioxidant status has been studied in sixteen trained male athletes aged 20-25years. Subjects performed 30-40minutes of treadmill running at 65% of VO2 max(high intensity exercise). Blood samples were taken before and immediately after two exercise bouts for measurement of blood antioxidants, indices of lipid peroxidation and susceptibility of crythrocyte to peroxidation. Plasma concentrations of cholesterol(7.3%), vitamin C(7.5%) and uric acid(2.1%) were elevated a little after exercise at 65% of VO2 max(13.7%)were significantly high than before exercise(p<0.05). However, these exercise-induced changes could be partly due to significant decreases in plasma volume which occurred after both exercise bouts(p<0.05). Plasma volume decreased 5.85$\pm$2.06% and 11.25$\pm$2.87% with exercise at 65% and 85% of VO2 max, respectively. The erythrocyte susceptibility to peroxidation after exercise at 65% of VO2 max was unchanged compared with the value before exercise, whereas after exercise at 85% of VO2 max, it was significantly higher than after exercise at 65% and 85% of VO2 max as well as before exercise(p<0.05). A significant increase at 85% of VO2 max, it was significantly high than after exercise at 85% of VO2 max (29.10$\pm$4.76ug/g Hb)when compared with the level before exercise (24.61$\pm$3.45ug/g Hb)(p<0.05). The results suggest that exercise-induced changes in plasma levels of lipid peroxide and antioxidant need to be evaluated, taking the shift in plasma volume into consideration. Also, exercise at high intensity corresponding to 85% of VO2 max alters the erythrocyte antioxidant status in relation to exercise-induced of oxidative stress.

• Korean Journal of Applied Biomechanics
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• v.25 no.3
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• pp.283-291
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• 2015

Objective : The purpose of this study was to determine the differences in the head and tibial acceleration signal magnitudes, and their powers and shock attenuations between flat-footed and normal-footed running. Methods : Ten flat-footed and ten normal-footed subjects ran barefoot on a treadmill with a force plate at 3.22m/s averaged from their preferred running speed using heel-toe running pattern while the head and tibial acceleration in the vertical axis data was collected. The accelerometers were sampled at 2000 Hz and voltage was set at 100 mv, respectively. The peak magnitudes of the head and tibial acceleration signals in time domain were calculated. The power spectral density(PSD) of each signal in the frequency domain was also calculated. In addition to that, shock attenuation was calculated by a transfer function of the head PSD relative to the tibia PSD. A one-way analysis of variance was used to determine the difference in time and frequency domain acceleration variables between the flat-footed and normal-footed groups running. Results : Peaks of the head and tibial acceleration signals were significantly greater during flat-footed group running than normal-footed group running(p<.05). PSDs of the tibial acceleration signal in the lower and higher frequency range were significantly greater during flat-footed running(p<.05), but PSDs of the head acceleration signal were not statistically different between the two groups. Flat-footed group running resulted in significantly greater shock attenuation for the higher frequency ranges compared with normal-footed group running(p<.05). Conclusion : The difference in impact shock magnitude and frequency content between flat-footed and normal-footed group during running suggested that the body had different ability to control impact shock from acceleration. It might be conjectured that flat-footed running was more vulnerable to potential injury than normal-footed running from an impact shock point of view.

• Journal of Life Science
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• v.18 no.9
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• pp.1263-1270
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• 2008

The purpose of this study is to investigate the effect of exercise mode and anti-hypertensive drug responding status on the cardiovascular response and perceived exertion in acute coronary syndrome (ACS) patients. Seventy-five patients who participated in six-week exercise rehabilitation therapy performed a treadmill running and a cycle ergometer exercise at intensities of 60%HRR and 85%HRR respectively. Systolic and diastolic blood pressure, mean arterial blood pressure (MAP), rate pressure production (RPP), and ratings of perceived exertion (RPE) were measured. The results of cardiovascular response by the different exercise modes with moderate and intensive intensity of anti-hypertensive drug responder and nonresponder ACS patients were following: First cycle ergometer exercise induced significantly higher SBP, DBP, MAP, RPP and MAP than treadmill running exercise at the intensities of 60%HRR and 85%HRR in both anti-hypertensive responder and nonresponder ACS patients (p<0.05). Secondly anti-hypertensive nonresponder ACS patients had significantly higher DBP and MAP that anti-hypertensive responder ACS patients at all the exercise modes (p<0.05). Finally there was no difference of RPP between anti-hypertensive responder and nomresponder ACS patients, although anti-hypertensive nonresponder ACS patients showed higher blood pressure and RPP than anti-hypertensive responder ACS patients. In conclusion, cycle ergometer induced increased cardiovascular response at same intensities of treadmill running exercise and anti-hypertensive nonresponder ACS patients had even more increased cardiovascular response than anti-hypertensive responder ACS patients with no difference in perceived exertion during exercise. These results suggested that cycle ergometer exercise should be greatly careful with the risk of higher blood pressure, especially for those who are patients with hypertensive blood pressure.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.21 no.5
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• pp.15-27
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• 2022

An omnidirectional VR treadmill is a highly-immersive walking simulator that allows identical body movements, such as walking, running, and sitting. However, the operation difficulty of an omnidirectional VR treadmill may cause data reliability problems. Therefore, this study aims to verify the effectiveness of a VR treadmill by comparing the ability to orient in the real and virtual worlds spatially. For this purpose, a rotating and searching path experiment was conducted with participants. This experiment showed that there was no statistically significant difference in the ability of the participants to orient in the real and virtual worlds spatially. In addition, the omnidirectional VR treadmill requires an adaptation time for the users due to the difficulty in the treadmill operation. However, there was no significant difference in the difficulty felt by the participants according to the adaptation time. Hence, these findings supported the possibility of collecting realistic walking data without safety concerns through an omnidirectional VR treadmill. Furthermore, this treadmill could be used in future research to solve problems directly related to pedestrian safety, such as the interaction between vehicles and pedestrians.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.11
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• pp.5849-5855
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• 2012

Objective: The purpose of this study was to determine pretreatment effects of moderate-term endurance training before the various dosages (10 and $20{_{mg.kg}}^{-1}$) of DOX on a heat shock protein ($HSP_{70kda}$) and cardiotoxicity in heart tissue. Methods: Forty-eight male rats were randomly assigned to nontraining (NT) and training (T) groups and three subgroups; $DOX{_{10mg.kg}}^{-1}$ and $DOX{_{20mg.kg}}^{-1}$ and saline treatment. The training program included treadmill running between 25-39 min/day and 15-17 m/min, 5 days/wk for 3 wk. Result: DOX administration, in particularly with $20{_{mg.kg}}^{-1}$, caused up-regulation of oxidants and cardiac damage (MDA, CK, CPK-MB and CK/CPK-MB) and down-regulation of cardioprotection ($HSP_{70}$, SOD) markers, as compared to NT+saline group. Pretreatment effect of treadmill running endurance exercise in the presence of DOX with $10{_{mg.kg}}^{-1}$ caused a significant increase in $HSP_{70}$, SOD and a significant decrease in MDA and insignificant decrease in CK, CPK-MB and CK/CPK-MB, in comparison $T+DOX_{10}$ with $NT+DOX_{10}$ group. However, there was no significant difference between $T+DOX{_{10mg.kg}}^{-1}$ and $T+DOX{_{20mg.kg}}^{-1}$ in the aforesaid markers. Conclusion: Dox-induced cardiotoxicity is related to oxidative stress. Our study suggests that pretreatment with endurance exercise may be considered as a potentially useful strategy to improve myocardial tolerance against single dose DOX-induced oxidative damage.

• The KIPS Transactions:PartD
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• v.18D no.2
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• pp.143-148
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• 2011

In this paper developed a wearable activity device and algorithm which can be converted into the real-time activity and monitoring by acquiring sensor row data to be occurred when a person is walking by using a tri-axial accelerometer. Test was proceeded at various step speeds such as slow walking, walking, fast walking, slow running, running and fast running, etc. for 36 minutes in accordance with the test protocol after wearing a metabolic test system(K4B2), Actical and the device developed in this study at the treadmill with 59 participants of subjects as its target. To measure the activity of human body, a regression equation estimating the Energy Expenditure(EE) was drawn by using data output from the accelerometer and information on subjects. As a result of experiment, the recognition rate of algorithm being proposed was shown the activity conversion algorithm was enhanced by 1.61% better than the performance of Actical.

• Journal of Biomedical Engineering Research
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• v.32 no.2
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• pp.79-84
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• 2011

The purpose of this study was to investigate the relevance of the prediction equations derived from the relationship between metabolic energy expenditure and kinetic energy, for different speeds of walking and running over the treadmill. Seven male subjects participated in this study. A tri-axial accelerometer was attached on between the left and right posterior superior iliac spines. Kinetic energy was calculated by the integration of acceleration data and compared with the metabolic energy measured by a gas analyzer. Correlation coefficients were determined to find a relationship between the kinetic energy and the metabolic energy expenditure. Also, the difference between measured and predicted values was used to find the relevance for individual and group equations. Results showed a relatively good correlation between the measured metabolic energy and the calculated kinetic energy. In addition, a dramatic increase in kinetic energy was observed at the transition speed of walking and running (6 km/h). There was no difference in how to predict the kinetic energy expenditure for individual and group even though people have different physical characteristics. This study would be useful to predict metabolic energy expenditures by the regression analysis with acceleration data.

• Korean Journal of Applied Biomechanics
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• v.29 no.3
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• pp.145-155
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• 2019

Objective: The purpose of this study was to compare the physical characteristics (bone mineral density, joint muscle strength) and running biomechanics between older adults and young adult runners to understand the changes of running strategy by aging. Method: Bone mineral density (Dual Energy X-ray Absorptiometry, USA) of lower lower extremity and muscle strength (Cybex Humac Norm [DEXA], CSMI, USA) were measured to identify the physical characteristics of 10 elderly (age: $67.70{\pm}3.30yrs$, height: $1.68{\pm}0.04m$, mass: $67.70{\pm}3.80kg$) and 10 young adults (age: $21.20{\pm}0.42yrs$, height: $1.73{\pm}0.06m$, mass: $72.11{\pm}4.15kg$). Running data was collected by using an instrumented treadmill (Bertec, USA) and 7 infrared cameras (Oqus 300, Qualisys, Sweden). Two-way repeated ANOVA analysis was used to analyze results at a significant level of .05 with Bonferroni post hoc analysis. Results: Compared to the young adult group, the elderly group showed statistically significant difference in physical characteristics and in running characteristics. Elderly runners showed lower BMD and muscle strength compared with young runners (p<.05). In the running parameters, elderly runners tend to show shorter contact time and stride length compared with young runners (p<.05). In the joint angles, elderly runners showed smaller range of ankle motion compared with young runners (p<.05). Finally, elderly runners showed lower level of joint moment, joint power, and GRF compared with young runners in each running speed (p<.05). Conclusion: The running behavior of the elderly performed periodic running was similar to many variables of young adults. However, there were noticeable differences found in the ankle joints and most kinetic variables compared with young adult runners. This discrepancy may propose that elderly runners should consider appropriate running distance and intensity in the program.

• Korean Journal of Applied Biomechanics
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• v.29 no.4
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• pp.247-254
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• 2019

Objective: The goal of this study was to determine the center of pressure (CoP) complexity pattern in approximate entropy technique between genders at different conditions of running speed. Background: It is conducted to evaluate the complexity pattern of CoP in the increment of running speed to have insights to injury prediction, stability, and auxiliary aids for the foot. Method: Twenty men (age=22.3±1.5 yrs.; height=176.4±5.4 cm; body weight=73.9±8.2 kg) and Twenty women (age=20.8±1.2 yrs.; height=162.8±5.2 cm; body weight=55.0±6.3 kg) with heel strike pattern were recruited for the study. While they were running at 2.22, 3.33, 4.44 m/s speed on a treadmill (instrumented dual belt treadmills, USA) with a force plate, CoP data were collected for the 10 strides. The complexity pattern of the CoP was analyzed using the ApEn technique. Results: The ApEn of the medial-lateral and antero-posterior CoP in the increment of running speed showed significantly difference within genders (p<.05), but there were not statistically significant between genders at all conditions of running speed. Conclusion: Based on the results of this study, CoP complexity pattern in the increment of running speed was limited to be characterized between genders as an indicator to judge the potential injury and stability. Application: In future studies, it is needed to investigate the cause of change for complexity of CoP at various running speed related to this study.

• Korean Journal of Applied Biomechanics
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• v.30 no.2
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• pp.145-154
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• 2020

Objective: The purpose of this study was to determine the relationship between impact and shear peak force, and tibia-accelerometer variables during running. Method: Twenty-five male heel strike runners (mean age: 23.5±3.6 yrs, mean height: 176.3±3.3 m/s, mean mass: 71.8±9.7 kg) were recruited in this study. The peak impact and anteroposterior shear forces during treadmill running (Bertec, USA) were collected, and impact shock variables were computed by using a triaxial accelerometer (Noraxon, USA). One-way ANOVA was used to test the influence of the running speed on the parameters. Pearson's partial correlation was used to investigate the relationship between the peak impact and shear force, and accelerometer variables. Results: The running speed affected the peak impact and posterior shear force, time, slope, and peak vertical and resultant tibial acceleration, slope at heel contact. Significant correlations were noticed between the peak impact force and peak vertical and resultant tibia acceleration, and between peak impact average slope and peak vertical and resultant tibia acceleration average slope, and between posterior peak (FyP) and peak vertical tibia acceleration, and between posterior peak instantaneous slop and peak vertical tibial acceleration during running at 3 m/s. However, it was observed that correlations between peak impact average slope and peak vertical tibia acceleration average slope, between posterior peak time and peak vertical and resultant tibia acceleration time, between posterior peak instantaneous slope and peak vertical tibial acceleration instantaneous slope during running at 4 m/s. Conclusion: Careful analysis is required when investigating the linear relationship between the impact and shear force, and tibia accelerometer components during relatively fast running speed.