• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.57 no.9
• /
• pp.1669-1673
• /
• 2008

A new cycle ergometer using a Magneto-Rheological (MR) rotary brake system has been developed for rehabilitation of hemiplegia patients to reduce uneven pedaling characteristics. For this purpose, a control method to adjust the resistance of the MR rotary brake in real time based on the magnitude of the muscular force exerted by the subject has been devised so that the mechanical resistance to the pedaling can be minimized when the affected leg was engaged for pedaling. A series of experiments were carried out with and without the engagement of this real-time control mode of MR rotary brake at different pedaling rate to find out the effect of the real-time control mode. The characteristics of the pedaling for these specific conditions were analyzed based on the variations in angular velocities of the pedal unit. The results showed that the variations in the angular velocities were decreased by 42.9% with the control mode. The asymmetry of pedaling between dominant and non-dominant leg was 19.63% in non-control mode and 1.97% in the control mode. The characteristics of electromyography(EMG) in the lower limbs were also measured. The observation showed that Integrated EMG(IEMG) reduced with the control mode. Therefore, the new bicycle system using MR brake with the real time control of mechanical resistance was found to be effective in recovering the normal pedaling pattern by reducing unbalanced pedaling characteristics caused by disparity of muscular strength between affected and unaffected leg.

• Journal of the Korea Safety Management & Science
• /
• v.12 no.4
• /
• pp.81-86
• /
• 2010

Despite the importance of cycling postures during cycling performances, there has been a very little research investigating cycling postures and pedaling rate for particularly concerning domestic cyclists. The aim of this study was to analyze correlations and effects between cycling postures and pedaling rate in track cycling. Twelve male racing cyclists (six racing and university cyclists) participated in this research. For this study, seven infrared cameras (Qualisys ProReflex MCU-240s) were used for collecting data and these were processed via QTM (Qualisys Tracker Manager) software. It appeared that pedaling rate had correlations with regard to a shoulder angle (R=-.601) and displacement between shoulder joints(R= -.637), but a knee (R=-.601) and ankle angle (R=.667). Moreover, two multiple regression equations of pedaling rate for cycling postures were significant and R2 of the first order equation y (pedaling rate) = 0.039x (knee angle) - 1.068 was less than the second order equation y = 0.006x2 - 1.287x + 69.674. In conclusion, cycling postures affected the pedaling rate. Further study should be researched on postures in relation to air resistance in a wind tunnel.

• Korean Journal of Applied Biomechanics
• /
• v.26 no.1
• /
• pp.11-20
• /
• 2016

Objective: This study aimed to compare biomechanical data between elite and beginner cyclists during cycle pedaling by performing a comparative analysis and to provide quantitative data for both pedaling performance enhancement and injury prevention. Methods: The subjects of this study included 5 elite cyclists (age: $18{\pm}0years$, body mass: $64.8{\pm}9.52kg$, height: $173.0{\pm}4.80cm$) and 5 amateur cyclists (age: $20{\pm}0years$, mass: $66.6{\pm}2.36kg$, height: $175.6{\pm}1.95cm$). The subjects pedaled on a stationary bicycle mounted on rollers of the same gear (front: 50 T and rear: 17 T = 2.94) and cadence of 90. The saddle height was adjusted to fit the body of each subject, and all the subjects wore shoes with cleats. In order to obtain kinematic data, 4 cameras (GR-HD1KR, JVC, Japan) were installed and set at 60 frames/sec. An electromyography (EMG) system (Telemyo 2400T, Noraxon, USA) was used to measure muscle activation. Eight sets of data from both the left and right lower extremities were obtained from 4 muscles (vastus medialis oblique [VMO], vastus lateralis oblique [VLO], and semitendinosus [Semitend], and lateral gastrocnemius [Gastro]) bilaterally by using a sampling frequency of 1,500 Hz. Five sets of events ($0^{\circ}$, $90^{\circ}$, $180^{\circ}$, $270^{\circ}$, and $360^{\circ}$) and 4 phases (P1, P2, P3, and P4) were set up for the data analysis. Imaging data were analyzed for kinematic factors by using the Kwon3D XP computer software (Visol, Korea). MyoResearch XP Master Edition (Noraxon) was used for filtering and processing EMG signals. Results: The angular velocity at $360^{\circ}$ from the feet was higher in the amateur cyclists, but accelerations at $90^{\circ}$ and $180^{\circ}$ were higher in the elite cyclists. The amateur cyclists had greater joint angles at $270^{\circ}$ from the ankle and wider knee joint distance at $0^{\circ}$, $180^{\circ}$, and $360^{\circ}$ than the elite cyclists. The EMG measurements showed significant differences between P2 and P4 from both the right VLO and Semitend. Conclusion: This study showed that lower body movements appeared to be different according to the level of cycle pedaling experience. This finding may be used to improve pedaling performance and prevent injuries among cyclists.

• Korean Journal of Applied Biomechanics
• /
• v.22 no.3
• /
• pp.357-363
• /
• 2012

The purpose of this study was to investigate the effects of different saddle heights on lower-limb joint angle and muscle activity. Six elite cyclists(age: $32.2{\pm}5.2years$, height: $171.0{\pm}3.5cm$, weight: $79.7{\pm}5.6kg$, cycle career: $13{\pm}6.2years$) participated in three min. submaximal(90 rpm) pedaling tests with the same load and cadence based on saddle heights where subject's saddle height was determined by his knee flexion angle when the pedal crank was at the 6 o'clock position. Joint angles(hip, knee, ankle joints) and the activity of lower limb muscles(biceps femoris(BF), vastus lateralis(VL), tibialis anterior(TA) and gastrocnemius medial(GM)) were compared by measuring 3D motion and electromyography(EMG) data. Results showed that there were significant differences in minimum hip & knee joint angle and range of motion of hip and knee joint between saddle heights. Onset timing and integrated EMG of only BF among 4 muscles were significantly different between saddle heights. Especially there was a negative relationship between minimum hip joint angle and onset timing of BF in most subject, which means that onset timing of BF became fast as the degree of bending of the hip joint became larger by saddle height. Optimal pedaling will be possible through increased amount of muscle activation due to the appropriate burst onset timing by proper pedaling posture with adjusted saddle height.

• Korean Journal of Applied Biomechanics
• /
• v.24 no.4
• /
• pp.417-423
• /
• 2014

The purpose of this study was to compare two saddle height determination methods by the effectiveness of pedal reaction force. Ten male subjects (age: $24.0{\pm}2.4years$, height: $175.1{\pm}5.4cm$, weight: $69.3{\pm}11.1kg$, inseam: $77.8{\pm}4.5cm$) participated in three minutes, 60 rpm cycle pedaling tests with the same load and cadence. Subject's saddle height was determined by $25^{\circ}$ knee flexion angle (K25) when the pedal crank was at the 6 o'clock position (knee angle method) and 97% (T97), 100% (T100), 103% (T103) of trochanter height (trochanteric method). The RF (resultant force), EF (effective force), and IE (index of effectiveness) were compared by measuring 3D motion and 3-axis pedal reaction force data during 4 pedaling phases (phase1: $330^{\circ}-30^{\circ}$, phase2: $30^{\circ}-150^{\circ}$, phase3: $150^{\circ}-210$, phase4: $210^{\circ}-330^{\circ}$). Results showed that there were significant differences in EF at phase1 between T97 and K25, in EF at phase4 between T100 and T103, in IE at total phase between T97 and K25, between T100 and T103, in IE at phase1 & phase2 between T97 and K25. There was higher IE in the K25 than any other saddle heights, which means that K25 was better pedaling effectiveness than the trochanteric method. Therefore it was suggested the saddle height as 103.7% of trochanter height that converted from K25.

• Korean Journal of Applied Biomechanics
• /
• v.26 no.3
• /
• pp.303-308
• /
• 2016

Objective: This study evaluated the vertical and horizontal forces in the frontal plane acting on a pedal due to the vertical alignment of the lower limbs. Method: Seven male subjects (age: $25.3{\pm} 0.8years$, height: $175.4{\pm}4.7cm$, weight: $74.7{\pm}14.2kg$, foot size: $262.9{\pm}7.6mm$) participated in two 2-minute cycle pedaling tests, with the same load and cadence (60 revolutions per minute) across all subjects. The subject's saddle height was determined by the height when the knee was at $25^{\circ}$ flexion when the pedal crank was at the 6 o'clock position (knee angle method). The horizontal force acting on the pedal, vertical force acting on the pedal in the frontal plane, ratio of the two forces, and knee range of motion in the frontal plane were calculated for four pedaling phases (phase 1: $330{\sim}30^{\circ}$, phase 2: $30{\sim}150^{\circ}$, phase 3: $150{\sim}210^{\circ}$, phase 4: $210{\sim}330^{\circ}$) and the complete pedaling cycle. Results: The range of motion of the knee in the frontal plane was decreased, and the ratio of vertical force to horizontal force and overall pedal force in the complete cycle were increased after vertical alignment. Conclusion: The ratio of vertical force to horizontal force in the frontal plane may be used as an injury prevention index of the lower limb.

• Journal of Digital Convergence
• /
• v.17 no.6
• /
• pp.389-399
• /
• 2019

The purpose of this study was to investigate the effects of muscle asymmetry of knee joint among elite cyclists on anaerobic pedaling power related capacity. In another word, based on isokinetic strength of Non-Dominant, ND and Dominant, D, side, high, moderate and low ratio of ND to D were classified as High Symmetry Group, Moderate Symmetry Group and Asymmetry Group, respectively. Analysis of muscle asymmetry of extensor's ND and D side might not lead to any difference between the three groups. Based on muscle strength analysis of the flexor's ND and D, there was statistical difference between the groups in ND flexor and in the muscle balance index of the flexor muscle. This result also leads to significant difference in pedaling power functionality, but this effects might not lead to any negative pedaling power. Therefore, among even cyclists who may show almost the same recruitment pattern of ND and D side during pedaling stroke muscle asymmetry could exist but this phenomena might not negatively contribute to the pedaling capacity.

• Korean Journal of Applied Biomechanics
• /
• v.26 no.2
• /
• pp.237-242
• /
• 2016

Objective: The purpose of this study was to compare the joint movements and muscle activities of novices according to pedal type (flat, clip, and cleat pedal). Method: Nine novice male subjects (age: $24.4{\pm}1.9years$, height: $1.77{\pm}0.05m$, weight: $72.4{\pm}7.6kg$, shoe size: $267.20{\pm}7.50mm$) participated in 3-minute, 60-rpm cycle pedaling tests with the same load and cadence. Each of the subject's saddle height was determined by the $155^{\circ}$ knee flexion angle when the pedal crank was at the 6 o'clock position ($25^{\circ}$ knee angle method). The muscle activities of the vastus lateralis, tibialis anterior, biceps femoris, and gastrocnemius medialis were compared by using electromyography during 4 pedaling phases (phase 1: $330{\sim}30^{\circ}$, phase 2: $30{\sim}150^{\circ}$, phase 3: $150{\sim}210^{\circ}$, and phase 4: $210{\sim}330^{\circ}$). Results: The knee joint movement (range of motion) and maximum dorsiflexion angle of the ankle joint with the flat pedal were larger than those of the clip and cleat pedals. The maximum plantarflexion timing with the flat and clip pedals was faster than that of the flat pedal. Electromyography revealed that the vastus lateralis muscle activity with the flat pedal was greater than that with the clip and cleat pedals. Conclusion: With the clip and cleat pedals, the joint movements were limited but the muscle activities were more effective than that with the flat pedal. The novice cannot benefit from the clip and cleat pedals regardless of their pull-up pedaling advantage. Therefore, the novice should perform the skilled pulling-up pedaling exercise in order to benefit from the clip and cleat pedals in terms of pedaling performance.

• Journal of rehabilitation welfare engineering & assistive technology
• /
• v.9 no.4
• /
• pp.331-337
• /
• 2015

This research was to develop the cycling system of lower limbs for rehabilitation during cycle exercise in supine position. Also we analyzed the muscular activity of lower-limbs at various exercise conditions according to exercise mode, load, velocity. 42 healthy subjects(ages 20-60 years) were participated. We measured the muscular activities of right lower limb muscle in rectus femoris, biceps femoris, tibialis anterior, medial gastrocnemius, soleus. Results, medial gastrocnemius shows high value on load 10 stage than load 1 and 5 stage. And all muscular activity except medial gastrocnemius was decreased as increase of velocity. We have found that there is a difference of lower limbs activity depending on exercise mode and method. This study could be applied to reference data to develop cycle system of lower limbs for rehabilitation.

• The Journal of Korean Physical Therapy
• /
• v.33 no.6
• /
• pp.292-296
• /
• 2021

Purpose: The purpose of this study was to investigate the exercise effect of two types of training with a recumbent cycle ergometer on ankle muscle strength (dorsiflexor strength, DFS; dorsiflexor strength/weight, DFS/kg; plantar flexor strength, PFS; and plantar flexor strength/weight, PFS/kg) in healthy male subjects. Methods: Twenty-three healthy males (27.91±8.66 yr) were randomly allocated into two groups (high-intensity interval training (HIIT), and aerobic exercise training (AET) after the first measurement. The subjects were trained for 24 sessions (40 min/rep, three times/week) and ankle strength was measured for a second time. Two-way mixed model analysis of variance (ANOVA) was used to identify significant differences between changes in ankle muscle strength between before and after training (within factors) in the HIIT and AET groups (between factors). The statistical significance level was set at α=0.05. Results: In both HIIT and AET groups, all variables of ankle muscle strength were significantly increased after training compared to before training (p=0.001). However, there were no differences in all variables of ankle strength between the HIIT and AET group (p>0.05). Conclusion: Both types (HIIT and AET) of recumbent cycle exercise training could be effective training methods to increase ankle muscle strength in healthy individuals, and the HIIT type with high intensity and low frequency pedaling could be recommended more to strengthen ankle muscles.