Synchronized Oxygen Delivery and Its Optimization Method: A Bench Study

Lee, Gil Jun,Cha, Seung Keun,Oh, Seung Kwon,Shin, Choongsoo S.,Lee, Tae Soo Korean Society for Precision Engineering 2013 International Journal of Precision Engineering and Vol.14 No.4

Long-term oxygen therapy (LTOT) has been widely used to treat patients with chronic obstructive pulmonary disease. The traditional oxygen delivery methods used for LTOT are continuous flow oxygen (CFO) and demand oxygen delivery (DOD). CFO wastes a considerable amount of oxygen, whereas DOD often makes patients feel uncomfortable because it abruptly supplies a large amount of oxygen at the onset of inhalation. Hence, we developed an algorithm for predicting the onset of inhalation, which allowed oxygen to be supplied smoothly before inhalation. Moreover, we minimized the discomfort index (DI) to offer more comfortable oxygen delivery. By integrating the prediction algorithm and the minimization of DI, the previous synchronized demand oxygen delivery (SDOD) method was modified. We constructed a bench model to validate the modified SDOD. The results showed that the proposed algorithm accurately predicted the onset of inhalation. The difference in the real-time measured and predicted values for the beginning of inhalation was less than 0.10 s. Using the proposed minimization technique, the DI was decreased by 50% under 20 breaths per minute when compared with the DI calculated from a previous study. In conclusion, the modified SDOD could supply oxygen more comfortably while synchronizing with patient breathing patterns.

Valgus Plus Internal Rotation Moments Increase Anterior Cruciate Ligament Strain More Than Either Alone

SHIN, CHOONGSOO S.,CHAUDHARI, AJIT M.,ANDRIACCHI, THOMAS P. The American College of Sports Medicine 2011 Medicine and science in sports and exercise Vol.43 No.8

PURPOSE:: To test the influence of combined knee valgus and internal tibial rotation moment on anterior cruciate ligament (ACL) strain during single-leg landing. We tested the following hypotheses: the combination of the valgus and internal rotation moments observed during single-leg landing produces a higher ACL strain than either moment applied individually, the combined rotational moments at the physiological levels observed could theoretically increase strain in the ACL high enough to rupture the ACL, and the location of the peak contact force was at the posterior-lateral side for combined loading. METHODS:: The study was conducted by applying in vivo human loading data to a validated simulation model of the three-dimensional dynamic knee joint to predict ACL strains. RESULTS:: The peak ACL strain increased nonlinearly when either applied valgus moment or internal rotation moment was increased in the model. When the two rotational moments were applied individually, neither caused ACL strain >0.077. However, when applied in combination, the two rotational moments had a much larger effect, and the predicted peak ACL strain increased up to 0.105. During landing, the peak contact force occurred at the posterior-lateral side of the tibial cartilage in the model when the combined maximum valgus moment and tibial internal rotation moments were applied. CONCLUSIONS:: Combined knee valgus and internal rotation moments increases ACL strain more than either alone. The combination of a valgus and internal rotational moment at magnitudes that occurs in vivo during landing can cause ACL strains that may be high enough to cause ACL rupture. This predicted high ACL strain and the contact force location suggest that combined valgus and internal tibial rotational moments during single-leg landing are relevant to ACL injuries.

In vivo tibiofemoral cartilage‐to‐cartilage contact area of females with medial osteoarthritis under acute loading using MRI

Shin, Choongsoo S.,Souza, Richard B.,Kumar, Deepak,Link, Thomas M.,Wyman, Bradley T.,Majumdar, Sharmila Wiley Subscription Services, Inc., A Wiley Company 2011 Journal of magnetic resonance imaging Vol.34 No.6

<P><B>Abstract</B></P><P><B>Purpose:</B></P><P>To investigate the effect of acute loading on in vivo tibiofemoral contact area changes in both compartments, and to determine whether in vivo tibiofemoral contact area differs between subjects with medial knee osteoarthritis (OA) and healthy controls.</P><P><B>Materials and Methods:</B></P><P>Ten subjects with medial knee OA (KL3) and 11 control subjects (KL0) were tested. Coronal three‐dimensional spoiled gradient‐recalled (3D‐SPGR) and T<SUB>2</SUB>‐weighted fast spin‐echo FSE magnetic resonance imaging (MRI) of the knee were acquired under both unloaded and loaded conditions. Tibiofemoral cartilage contact areas were measured using image‐based 3D models.</P><P><B>Results:</B></P><P>Tibiofemoral contact areas in both compartments significantly increased under loading (<I>P</I> < 0.001) and the increased contact area in the medial compartment was significantly larger than in the lateral compartment (<I>P</I> < 0.05). Medial compartment contact area was significantly larger in KL3 subjects than KL0 subjects, both at unloaded and loaded conditions (<I>P</I> < 0.05). Contact areas measured from 3D‐SPGR and T<SUB>2</SUB>‐weighted FSE images were strongly correlated (<I>r</I> = 0.904).</P><P><B>Conclusion:</B></P><P>Females with medial OA increased tibiofemoral contact area in the medial compartment compared to healthy subjects under both unloaded and loaded conditions. The contact area data presented in this study may provide a quantitative reference for further cartilage contact biomechanics such as contact stress analysis and cartilage biomechanical function difference between osteoarthritic and healthy knees. J. Magn. Reson. Imaging 2011;. © 2011 Wiley Periodicals, Inc.</P>

전방십자인대 부상환자와 재건환자에 나타나는 경대퇴 관절운동과 슬개대퇴 관절운동의 상관성 비교

신충수(Choongsoo Shin),데이나 카펜터(R. D. Carpenter),샤밀라 마줌다(S. Majumdar),벤마(B. Ma) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.4

Comparison of Lower Extremity Kinematics and Kinetics during Downhill and Valley-shape Combined Slope Walking

Jeong, Jiyoung,Shin, Choongsoo S. Korean Society of Sport Biomechanics 2016 한국운동역학회지 Vol.26 No.2

Objective: The purpose of this study was to determine the knee and ankle joint kinematics and kinetics by comparing downhill walking with valley-shape combined slope walking. Method: Eighteen healthy men participated in this study. A three-dimensional motion capture system equipped with eight infrared cameras and a synchronized force plate, which was embedded in the sloped walkway, was used. Obtained kinematic and kinetic parameters were compared using paired two-tailed Student's t-tests at a significance level of 0.05. Results: The knee flexion angle after the mid-stance phase, the mean peak knee flexion angle in the early swing phase, and the ankle mean peak dorsiflexion angle were greater during downhill walking compared with valley-shape combined slope walking (p < 0.001). Both the mean peak vertical ground reaction force (GRF) in the early stance phase and late stance phase during downhill walking were smaller than those values during valley-shape combined slope walking. (p = 0.007 and p < 0.001, respectively). The mean peak anterior GRF, appearing right after toe-off during downhill walking, was also smaller than that of valley-shape combined slope walking (p = 0.002). The mean peak knee extension moment and ankle plantar flexion moment in late stance phase during downhill walking were significantly smaller than those of valley-shape combined slope walking (p = 0.002 and p = 0.015, respectively). Conclusion: These results suggest that gait strategy was modified during valley-shape combined slope walking when compared with continuous downhill walking in order to gain the propulsion for lifting the body up the incline for foot clearance.

Comparison of Lower Extremity Kinematics and Kinetics during Downhill and Valley-shape Combined Slope Walking

( Jiyoung Jeong ),( Choongsoo S. Shin ) 한국운동역학회 2016 한국운동역학회지 Vol.26 No.2

Objective: The purpose of this study was to determine the knee and ankle joint kinematics and kinetics bycomparing downhill walking with valley-shape combined slope walking.Method: Eighteen healthy men participated in this study. A three-dimensional motion capture systemequipped with eight infrared cameras and a synchronized force plate, which was embedded in the slopedwalkway, was used. Obtained kinematic and kinetic parameters were compared using paired two-tailedStudent``s t-tests at a significance level of 0.05.Results: The knee flexion angle after the mid-stance phase, the mean peak knee flexion angle in the earlyswing phase, and the ankle mean peak dorsiflexion angle were greater during downhill walking comparedwith valley-shape combined slope walking (p < 0.001). Both the mean peak vertical ground reaction force(GRF) in the early stance phase and late stance phase during downhill walking were smaller than thosevalues during valley-shape combined slope walking. (p = 0.007 and p < 0.001, respectively). The mean peakanterior GRF, appearing right after toe-off during downhill walking, was also smaller than that of valleyshapecombined slope walking (p = 0.002). The mean peak knee extension moment and ankle plantar flexionmoment in late stance phase during downhill walking were significantly smaller than those of valleyshapecombined slope walking (p = 0.002 and p = 0.015, respectively).Conclusion: These results suggest that gait strategy was modified during valley-shape combined slopewalking when compared with continuous downhill walking in order to gain the propulsion for lifting thebody up the incline for foot clearance.

The effect of landing technique on lower extremity joint kinematics and kinetics during single leg landing

( Jiyoung Jeong ),( Choongsoo S. Shin ) 한국체육학회 2016 국제스포츠과학 학술대회 Vol.2016 No.1

Purpose: The purpose of this study was to examine the effect of two different landing techniques (forefoot and rearfoot) on lower extremity joint kinematics and /kinetics during single leg landing. Method: Five males (age: 25.6±1.5 yrs, height: 174.6±3.4 cm, mass: 70.4±4.3 kg) were recruited. All participants performed single leg landing by stepping off a 30-cm platform in two different landing techniques; forefoot and rearfoot contact landing. Three dimensional hip, knee, and ankle joint kinematics and kinetics were calculated using motion capture system equipped with six infrared cameras sampled at 400Hz. Obtained kinematic and kinetic parameters were compared using a paired two-tailed Student’s t test at a significance level of 0.05. Result: At initial contact, there were significant differences in the ankle plantar(+)/dorsi(-) flexion angle (forefoot: 10.7±2.0°, rearfoot: -21.2±8.5°, p<0.001), the ankle inversion(+)/eversion(-) angle (forefoot: 2.3±1.5°, rearfoot: -0.1±1.1°, p=0.017), and the hip external(+)/internal(-) rotation angle (forefoot: 9.8±3.1°, rearfoot: -1.1±3.7°, p=0.001). The peak knee extension moment (forefoot: 0.222±0.021 Nm/(BW*Ht), rearfoot: 0.260±0.042 Nm/(BW*Ht), p<0.001), the peak knee valgus moment (forefoot: 0.078±0.005 Nm/(BW*Ht), rearfoot: 0.090±0.021 Nm/(BW*Ht), p<0.001), and the peak tibial internal rotation moment (forefoot: 0.012±0.004 Nm/(BW*Ht), rearfoot: 0.009±0.002 Nm/(BW*Ht), p<0.001) were significantly greater during rearfoot landing when compared to forefoot landing. The peak ankle plantarflexion moment was significantly smaller during rearfoot landing (forefoot: 0.239±0.058 Nm/(BW*Ht), rearfoot: 0.139±0.030 Nm/(BW*Ht), p<0.001), but the peak ankle varus moment was greater than forefoot landing (forefoot: 0.025±0.011 Nm/(BW*Ht), rearfoot: 0.041±0.013 Nm/(BW*Ht), p<0.001). Conclusion: The present study showed significant differences in 3D hip, knee, and ankle joint kinematics and kinetics between forefoot and rearfoot landing. The combination of the knee valgus and internal tibial rotation moment increase the risk of anterior cruciate ligament injury. Also, many ankle sprains occur during the combined movement of inversion and plantarflexion. Therefore, the results of this study suggest that altering landing technique may bring the lower extremity injury risks.

The Effect of Foot Landing Type on Lower-extremity Kinematics, Kinetics, and Energy Absorption during Single-leg Landing

Jeong, Jiyoung,Shin, Choongsoo S. Korean Society of Sport Biomechanics 2017 한국운동역학회지 Vol.27 No.3

Objective: The aim of this study was to examine the effect of foot landing type (forefoot vs. rearfoot landing) on kinematics, kinetics, and energy absorption of hip, knee, and ankle joints. Method: Twenty-five healthy men performed single-leg landings with two different foot landing types: forefoot and rearfoot landing. A motion-capture system equipped with eight infrared cameras and a synchronized force plate embedded in the floor was used. Three-dimensional kinematic and kinetic parameters were compared using paired two-tailed Student's t-tests at a significance level of .05. Results: On initial contact, a greater knee flexion angle was shown during rearfoot landing (p < .001), but the lower knee flexion angle was found at peak vertical ground reaction force (GRF) (p < .001). On initial contact, ankles showed plantarflexion, inversion, and external rotation during forefoot landing, while dorsiflexion, eversion, and internal rotation were shown during rearfoot landing (p < .001, all). At peak vertical GRF, the knee extension moment and ankle plantarflexion moment were lower in rearfoot landing than in forefoot landing (p = .003 and p < .001, respectively). From initial contact to peak vertical GRF, the negative work of the hip, knee, and ankle joint was significantly reduced during rearfoot landing (p < .001, all). The contribution to the total work of the ankle joint was the greatest during forefoot landing, whereas the contribution to the total work of the hip joint was the greatest during rearfoot landing. Conclusion: These results suggest that the energy absorption strategy was changed during rearfoot landing compared with forefoot landing according to lower-extremity joint kinematics and kinetics.

Effect of ankle flexion angle at initial contact on the contribution of lower extremity muscles to reduce landing impact

Jinkyu Lee,Choongsoo S. Shin 대한기계학회 2019 대한기계학회 춘추학술대회 Vol.2019 No.4

The Effect of Foot Landing Type on Lower-extremity Kinematics, Kinetics, and Energy Absorption during Single-leg Landing

( Jiyoung Jeong ),( Choongsoo S. Shin ) 한국운동역학회 2017 한국운동역학회지 Vol.27 No.3

Objective: The aim of this study was to examine the effect of foot landing type (forefoot vs. rearfoot landing) on kinematics, kinetics, and energy absorption of hip, knee, and ankle joints. Method: Twenty-five healthy men performed single-leg landings with two different foot landing types: forefoot and rearfoot landing. A motion-capture system equipped with eight infrared cameras and a synchronized force plate embedded in the floor was used. Three-dimensional kinematic and kinetic parameters were compared using paired two-tailed Student`s t-tests at a significance level of .05. Results: On initial contact, a greater knee flexion angle was shown during rearfoot landing (p < .001), but the lower knee flexion angle was found at peak vertical ground reaction force (GRF) (p < .001). On initial contact, ankles showed plantarflexion, inversion, and external rotation during forefoot landing, while dorsiflexion, eversion, and internal rotation were shown during rearfoot landing (p < .001, all). At peak vertical GRF, the knee extension moment and ankle plantarflexion moment were lower in rearfoot landing than in forefoot landing (p = .003 and p < .001, respectively). From initial contact to peak vertical GRF, the negative work of the hip, knee, and ankle joint was significantly reduced during rearfoot landing (p < .001, all). The contribution to the total work of the ankle joint was the greatest during forefoot landing, whereas the contribution to the total work of the hip joint was the greatest during rearfoot landing. Conclusion: These results suggest that the energy absorption strategy was changed during rearfoot landing compared with forefoot landing according to lower-extremity joint kinematics and kinetics.