• Design & Manufacturing
• /
• v.11 no.2
• /
• pp.29-36
• /
• 2017

In this study, the non-contact type bicycle generator system considering the recharge is developed to use the eco-friendly energy source when the bicycle is operating. The following three main factors are considered in this study. One of factors is that the intensity of the rotating magnet is in the range of 2,700~4,300 [Gause]. The next factor is that the separation distance of rotating magnet and bicycle rim is in the range of 1.5-3.0 mm. The last factor is that the pedaling speed is in the range of 55 RPM [Wheel speed 5.6Km]~150 RPM [Wheel speed 15.25Km] consirering with the 5 staged gear transmission. The obtained results are as followed. (1) The generator output voltage gradually increases from 3V to 10V with the pedaling speed increases, at the separation distance is less than 2.5 mm and the operating voltage of the LED lamp is generated at a pedaling speed of 60 RPM or more. (2) The output current of the generator increases from 20mA to 40mA with the pedaling speed increases, at a separation distance is less than 2.0 mm and the operating current of the LED lamp is generated at a pedaling speed of 60 RPM or more. (3) When the separation distance was 3.0 mm, the output voltage and current are significantly lower than those of the bicycle LED lamp is generated. (4) The charging time is expected to be 12.24 ~ 17.65 hours when the magnitude of the magnet is 3,400[Gauss] at a pedaling speed of 55 RPM or more. (5) As a result of this study, it is thought that the non-contact type bicycle generator system considering the recharge can replace the conventional friction power generation system.

• Physical Therapy Korea
• /
• v.29 no.4
• /
• pp.262-268
• /
• 2022

Background: Virtual reality (VR) programs based on motion capture camera are the most convenient and cost-effective approaches for remote rehabilitation. Assessment of physical function is critical for providing optimal VR rehabilitation training; however, direct muscle strength measurement using camera-based kinematic data is impracticable. Therefore, it is necessary to develop a method to indirectly estimate the muscle strength of users from the value obtained using a motion capture camera. Objects: The purpose of this study was to determine whether the pedaling speed converted using the VR engine from the captured foot position data in the VR environment can be used as an indirect way to evaluate knee muscle strength, and to investigate the validity and reliability of a camera-based VR program. Methods: Thirty healthy adults were included in this study. Each subject performed a 15-second maximum pedaling test in the VR and built-in speedometer modes. In the VR speedometer mode, a motion capture camera was used to detect the position of the ankle joints and automatically calculate the pedaling speed. An isokinetic dynamometer was used to assess the isometric and isokinetic peak torques of knee flexion and extension. Results: The pedaling speeds in VR and built-in speedometer modes revealed a significantly high positive correlation (r = 0.922). In addition, the intra-rater reliability of the pedaling speed in the VR speedometer mode was good (ICC [intraclass correlation coefficient] = 0.685). The results of the Pearson correlation analysis revealed a significant moderate positive correlation between the pedaling speed of the VR speedometer and the peak torque of knee isokinetic flexion (r = 0.639) and extension (r = 0.598). Conclusion: This study suggests the potential benefits of measuring the maximum pedaling speed using 3D depth camera in a VR environment as an indirect assessment of muscle strength. However, technological improvements must be followed to obtain more accurate estimation of muscle strength from the VR cycling test.

• Korean Journal of Applied Biomechanics
• /
• v.18 no.4
• /
• pp.171-177
• /
• 2008

This work intends to investigate the effects of pedaling directions on the muscle actions during the bicycle's uphill propulsion. A test rig was developed that consists of a bicyle with a special planetary geartrain, a height-adjustable treadmill, a rear-wheel support and a magnetic brake. A three-dimensional motion analysis was performed for measuring kinematic characteristics of the forward backward pedaling and the electromygraphy(EMG) measurements were simultaneously performed for estimating the muscle actions of the leg. In this work, four muscles are considered including Gastrocnemius muscle(GM), Vastus lateralis(VL), Tibialis anterior(TA) and Soleus(SOL) while the uphill slope is varied from $0^{\circ}$ to $6^{\circ}$. Raw EMG signals were first processed through the root-mean-square(RMS) averaging and then ensemble curves were derived by averaging the EMG RMS envelopes over 50 consecutive cycles. Results show that both the kinemactic characteristics and the muscle actions are significantly affected by the pedaling direction. The crank speed of the forward pedaling is higher but the difference in speed is reduced as the slope is increased. The ensemble curves of the :ac signals clearly exhibit some differences in their patterns, peak values and the corresponding locations with respect to the crank angle. The peak values of most EMG signals are higher for the forward pedaling regardless of the slope magnitude. However, the averages of the EMG signals are not observed to have a similar relationship with the pedaling direction, which seems to be affected by several factors such as less experience of the participants' backward pedaling. inappropriate bicycle design for the backward pedaling. These limitations will be further considered in future work.

• The Journal of Korean Physical Therapy
• /
• v.23 no.1
• /
• pp.7-11
• /
• 2011

Purpose: Driving is essential to maintain independent living status in modern times. Many patients want to know when they can drive again, but it's only possible if they have the ability to control lower extremity muscles. In this study, we compared the effects of velocity on onset time of lower extremity muscles during driving tasks. Methods: Twelve participants (5 male, 7 female) were enrolled. EMGs were used to test the onset time of lower extremity muscles; tibialis anterior, soleus, rectus femoris. To analyze the data, we used two way ANOVA. Results: According to brake pedaling velocity, there was a significant difference in brake response time (p<0.05). Further, when comparing the lower extremity muscles, there was a significant difference in onset time (p<0.05). The order of muscle recruitment was tibialis anterior, rectus femoris, and soleus for achieving maximal velocity, but the order was rectus femoris, tibialis anterior, soleus for achieving submaximal velocity. Conclusion: Brake pedaling velocity has significant effects on onset time of muscle contractions in the lower extremities. We suggested that a future study needs more subjects and more detailed research such as evaluat-ions of visuo-motor coordination and fine motor dexterity.

• Journal of Fisheries and Marine Sciences Education
• /
• v.29 no.2
• /
• pp.537-543
• /
• 2017

The purpose of this research is to investigate the effects of different shoe-cleat position on pedalling performance. Four male elite triathletes(age: $22.00{\times}2.16years$, height: $175.12{\pm}8.06cm$, weight: $71.20{\pm}7.89kg$, body fat: $16.62{\pm}3.56%$) and three female elite triathletes(age: $20.00{\pm}1years$, height: $158.40{\pm}2.42cm$, weight: $51.30{\pm}3.89kg$, body fat: $19.26{\pm}2.28%$) participated in 10km time trial and 30sec time trial pedaling tests with the individual time trials based on different shoe-cleat position(cleat front: CF, cleat back: CB). The subjects performed one trial with each type of shoe-cleat position. Maximal power output and average speed were not significantly different during 30s time trial in CF compared with CB. Average power, RPM, and HR were not significantly different during 10k time trial in CF compared with CB. Split time in 1km, 5km, 9km were significantly reduced during 10k time trial in CB compared with CF. We conclude that there was performance advantage in CB using shoe-cleat back position in comparison with CF using shoe-cleat front position.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2002.05a
• /
• pp.604-609
• /
• 2002

In development of an advanced bicycle simulator, the investigation of the interactions between bicycle and rider during cycling is paramount important because bicycle is a two-wheeled human-powered vehicle. Tn this work, the tilt stability. among various interactions, of bicycling is investigated experimentally, In the experiments, the tilt angles of the bicycle, riders body and head are measured, as the riding p;1th and the speed are varied. Subjects are asked to ride along four typical paths on rigid flat ground : the straight, C-curved, S-curved and circle paths. The results from extensive experiments with different subjects can be summarized as : 1) The tilt angles of bicycle and rider are almost out of phase during pedaling along the straight path. 2) The bicycle tilt angle is nearly proportional to the square of bicycle speed for the straight and curved paths, and to the curvature for the curved paths. The head tilt angle is the biggest and the body tilt angle is the smallest for the straight path, but the tendency is reversed for the C-curved path. During the curve maneuvering, the rider's head tends to tilt by less than 40% of the bicycle tilt angle.

• Journal of Biomedical Engineering Research
• /
• v.3 no.1
• /
• pp.23-30
• /
• 1982

The regimen of physical activity of the patient with coronary artery disease requires that he should not overshoot the prescribed heart rate based on his age, health and fuctional status of the heart during his exercise. The step input of work load, however, involves a great danger of overshooting. The purpose of this study was to desigil a system that makes it passible for a subject to check the overshooting. This system shows on tile H.R-meter, the amplified and filtered heart-rate signal of the subject received by the photosensor on his earlobe, puts it in the lead coinpensational circuit where it is conpared with the reference input signal(=the presfribed heart rate). The output of the lead compensational circuit works the aull meter. By means of this null meter, the subject knows whether he is overshooting the prescribed heart rate or not. He can continue the natl meter needle at the'Zero'position through the control of the speed of pedaling of the bicycle ergometer, An experimental test, made on eight men and four women in healthy condition, showed that 91. 7% of them vlaintained the stable heart rate and that the overshooting of the desired heart rate did not exceed $\pm$2BPM. According to the result of this experiment, since the heart rate feedback controller makes it possible for the subject to take the prescribed exercise based not on the work load but on the heart rate which incidentally is inexpensive, it can be made use of as the instrument for the regimen of pflysical activity by the patient with coronary artery disease.

• Journal of the Korean Society for Precision Engineering
• /
• v.24 no.10
• /
• pp.137-145
• /
• 2007

The purpose of this study is developing a virtual bicycle system for improving the ability of postural balance control for adults in various age groups. The system consists of an exercise bicycle that allows tilt in accordance with the postural balance of the subject in the system, a visual display that shows virtual road, and a visual feedback system. The rider of the system tries to maintain balance on the bicycle with a visual feedback of a virtual road while the pedaling speed, the heading direction, and various weight distribution information are updated to the subject as visual feedbacks in the display. A series of experiments were performed with various subjects to find the factors related to postural balance control in the system. The related parameters obtained were weight shift, magnitude of the deviation from the center of the virtual road, and variables related to the movement of the center of pressure. The results found that the ability to control postural balance in the system improved with the presentation of visual feedback information of the distribution of weight. It was also found that the general performance of the subject on balance in the system improved after ten days long training. The results show that the newly developed system can be used for the diagnosis of postural balance as well as for the stimulation of various senses such as vision and somatic sense in the field of rehabilitation training.

• PNF and Movement
• /
• v.20 no.2
• /
• pp.179-187
• /
• 2022

Purpose: The purpose of this study was to determine the asymmetrical difference between the use of leg muscles on the surgical and non-surgical sides during initial lower extremity ergometer exercise after unilateral knee arthroplasty. Methods: Twelve elderly patients diagnosed with degenerative arthritis of the knee and who underwent unilateral arthroplasty were included in this study. The leg length of each subject was taken into account when setting the application distance of the lower extremity ergometer. The same pedal resistance, strength, and speed were used for all the subjects. The total angle of use of the ergometer (360°) was analyzed by dividing it into an extension section and a flexion section. Using a surface electromyography system, the activities of the muscles of the surgical and non-surgical sides were converted into maximal voluntary isometric contraction (MVIC) and analyzed using the paired t-test. Results: When the activities of the muscles on the surgical and non-surgical sides were compared, it was found that the rectus femoris and biceps femoris had significant differences in the flexion and extension sections (p < .05), and that the tibialis anterior significantly differed in the flexion section (p < .05). There was no significant difference in the extension section of the tibialis anterior muscle, or in the flexion and extension sections of the gastrocnemius (p >.05). Conclusion: The results of this study confirm that the rectus femoris, tibialis anterior, biceps femoris, and gastrocnemius on the surgical side act in an opposite manner to those on the non-surgical side during pedaling in the same section.