Joint Flexion Angle Research Articles

Development of a Traumatic Anterior Cruciate Ligament and Meniscal Rupture Model With a Pilot In Vivo Study

The current study describes the development of a small animal, closed-joint model of traumatic anterior cruciate ligament (ACL) and meniscal rupture. This model can be used in future studies to investigate the roles of these acute damages on the long-term health of an injured knee joint. Forty-two Flemish Giant rabbits received an insult to the left tibiofemoral joint ex vivo in order to document optimal energy and joint orientation needed to generate ACL and meniscal rupture, without gross fracture of bone. Impact energies ranged from 10 J to 22 J, and joint flexion angle ranged from 60 deg to 90 deg. Three in vivo animals were impacted at 13 J with the knee flexed at 90 deg, as this was determined to be the optimal load and joint orientation for ACL and meniscal ruptures, and sacrificed at 12 weeks. Impact data from the ex vivo group revealed that 13 J of dropped-mass energy, generating approximately 1100 N of load on the knee, would cause ACL and meniscal ruptures, without gross bone fracture. Acute damage to the lateral and medial menisci was documented in numerous ex vivo specimens, with isolated lateral meniscal tears being more frequent than isolated medial tears in other cases. The in vivo animals showed no signs of ill health or other physical complications. At 12 week post-trauma these animals displayed marked degeneration of the traumatized joint including synovitis, cartilage erosion, and the formation of peripheral osteophytes. Histological microcracks at the calcified cartilage-subchondral bone interface were also evident in histological sections of these animals. A closed-joint model of traumatic ACL and meniscal rupture was produced, without gross bone fracture, and a pilot, in vivo study showed progressive joint degeneration without any other noticeable physical impairments of the animals over 12 weeks. This closed-joint, traumatic injury model may be useful in future experimental studies of joint disease and various intervention strategies.

Posture and muscular behaviour in emergency braking: An experimental approach

In the field of numerical crash simulations in road safety research, there is a need to accurately define the initial conditions of a frontal impact for the car occupant. In particular, human models used to simulate such impacts barely take into account muscular contracting effects. This study aims to quantify drivers’ behaviour in terms of posture and muscular activity just before a frontal impact. Experiments on volunteers were performed in order to define these conditions, both on a driving simulator and on a real moving car. Brake pedal loads, lower limbs kinematics and muscle activation were recorded. Coupling instantaneous data from both experimental protocols (simulator versus Real car), a standard emergency braking configuration could be defined as (1) joint flexion angles of 96°, 56° and 13° for the right hip, knee and ankle respectively; (2) a maximum brake pedal load of 780 N; (3) a muscular activation of 55% for the anterior thigh, 26% for the posterior thigh, 18% for the anterior leg and 43% for the posterior leg. The first application of this research is the implementation of muscle tone in human models designed to evaluate new safety systems.

Hindlimb response to tactile stimulation of the pastern and coronet

Lightweight tactile stimulators attached to the hind pasterns increase the height of the hind hoof flight arc but details of the induced changes in swing phase kinematics and kinetics have not been investigated. Stimulators on the hind pasterns are associated with increased hindlimb joint flexions and increased positive work performed by the hip and tarsal musculature. Nine nonlame horses trotted 4 times with and without 55 g tactile stimulators loosely attached around the hind pasterns. Height of the flight arc and peak flexion angles of the hindlimb joints were measured and net positive and negative work performed across each joint during the swing phase were calculated using inverse dynamics analysis and compared across paired conditions. Speed and stride duration did not change but stimulators were associated with a reduction in hind stance duration. The flight arc was higher with stimulators due to increased flexions of the stifle, tarsal, metatarsophalangeal and distal interphalangeal joints. Positive work increased in the tarsal musculature, but not in the hip musculature, and negative work increased across the stifle, metatarsophalangeal and distal interphalangeal joints. The effects of tactile stimulation of the hind pasterns on joint motion and muscle activation may be used in physiotherapy and rehabilitation to restore or increase flexion of the hindlimb joints with the exception of the hip joint. The ability to stimulate concentric activity of the tarsal musculature may have therapeutic applications in conditions such as toe dragging.

경사로 오르기 동안 슬관절 굴곡각도와 족저압의 특성 비교

This study was to investigate the knee joint flexion angle and the foot pressure during climbing with different slope. The 24 healthy subjects were participated. And foot pressure was investigated using Parotec system. The knee joint flexion angle were filmed to using a video camera on each slope(). And knee joint angle was investigated by Dartfish. The data were analyzed ANOVAs. In conclusion, there was significantly different that knee joint flexion angle related on each slope angle. In foot pressure, there was significantly different in lateral heel area(1 cell), medial midfoot area(9 cell), medial forefoot area(15, 16 cell) of left foot, and in lateral heel area(3 cell) of right foot. There was significantly different of foot pressure in lateral and medial heel when knee joint flexion angle is between and . There was change of gait cycle according to walking slop angle increasing, and the initial contact phase was shorter, the foot pressure in lateral heel was lower.

Motion Analysis of Thumb in Cellular Phone Use

The thumb motion of 10 normal subjects during cellular phone use was measured using a reflective marker detection system to compare the maximum, minimum and range of flexion angles of the interphalangeal (IP), metacarpophalangeal (MP) and carpometacarpal (CM) joints. Two micro-reflective markers 3 mm in diameter were each placed on the dorsal surface of the distal phalanx, basal phalanx and metacarpal bone of the thumb. Three markers were placed on the dorsal hand in order to define the dorsal hand plane. Each subject pushed the 12 keys of a folding cellular phone with an 85-mm-long and 40-mm-wide keypad, sequentially from ‘1’ to ‘#’, and the pushing motion was recorded by six infrared video cameras for 12 seconds, using the VICON 612 system. The mean maximum flexion angle of the MP joint was significantly (p< .05) larger than the CM joint, and the mean minimum flexion angle of the CM joint was significantly (p< .01) smaller than the IP and MP joints. The mean range of motion of the IP joint was significantly (p< .05) larger than the MP and the CM joints. In a comparison of different key-pushing motions, only the CM joint was significantly (p< .05) larger in its range of motion. In conclusion, thumb motion on pushing the keys of the cellular phone was produced mainly by the MP and the CM joints. In addition, the ability to reach keys in different areas of the cellular phone keypad is regulated by changing the flexion angle of the CM joint.

Dynamic Tenodesis of the Finger Extensors to Improve Hand Function after Brachial Plexus Injury

The term "plexic hand" refers to hand and wrist involvement in traumatic brachial plexus injuries and to remaining deficits after nerve surgery has been performed. From January 2000 to March 2008, reconstructive surgery (dynamic tenodesis) was performed on seven patients with C5, 6, 7, and 8 nerve root lesions of the brachial plexus to restore wrist and finger extension. This procedure has been used in seven patients (one female). Two patients with a lesion of the brachial plexus sustained a fracture of the affected limb. Preliminary nerve repair operations were required in four cases. One hundred percent (seven) of the patients had improved function following dynamic tenodesis. The extension angle of the wrist joint on grip was 19° on average. The flexion angle of the wrist joint needed to produce MP joint extension was 24.3° on average. A new dynamic extensor tenodesis technique is proposed. The extensor digitorum communis tendons are looped through dorsal carpal retinaculum ligament and sutured to themselves. Our results demonstrate that the extensor dynamic tenodesis procedure is an effective and simple means of restoring grip function for patients with C5, 6, 7, and 8 nerve root lesions.

Wearable Sensing Glove With Embedded Hetero-Core Fiber-Optic Nerves for Unconstrained Hand Motion Capture

In this paper, we present a wearable sensing glove with embedded hetero-core fiber-optic nerve sensors that detect finger flexion to achieve unconstrained hand motion monitoring. The hetero-core fiber sensor is suited to the wearable sensing glove because it is capable of optical intensity-based measurements with excellent stability and repeatability using single-mode transmission fibers and is unaffected by temperature fluctuations. The hetero-core sensor elements are located on the back of the hand so that they are not affected by random wrinkles in the glove at the joints. As a result, the hetero-core flexion sensor after calibration is capable of detecting the joint angles of the fingers regardless of differences in hand size, and the hetero-core sensing technique enables the sensing glove to be constructed with a minimum number of sensor points. The optical loss performance of the hetero-core sensors reveals monotonic characteristics with respect to the flexion angle of joints. The optical loss is 1.35 dB for a flexion angle of approximately 97.2deg with accuracy of 0.89deg in the detected flexion angle. Real-time hand motion capture was demonstrated by means of the proposed sensing glove without restricting natural human behavior.

Evaluation of Torque of the Shank Rotating Muscles and the Range of Active Internal and External Rotation of the Knee Joint in Patients Awaiting ACL Reconstruction

Evaluation of Torque of the Shank Rotating Muscles and the Range of Active Internal and External Rotation of the Knee Joint in Patients Awaiting ACL ReconstructionPurpose. The aim of the study was threefold: to determine the active rotation range of a healthy and post-traumatic knee joint; to evaluate the torque of muscles responsible for internal and external rotation of a healthy and post-traumatic knee joint; and to determine differences between a healthy knee joint and knee joint with the ruptured anterior cruciate ligament (ACL). Differences between active axial rotation and muscular strength of rotators in the healthy and post-traumatic knee joints of 40 hospitalized patients were examined. Basic procedures. The static torque evaluation of the shank rotating muscles included 40 patients of the Endoscopic Surgery Clinic in Żory, with the ruptured ACL of the right knee, qualified for surgery (ACL reconstruction). On the basis of a medical interview, the ACL ruptures were found to have occurred during football games. Main findings. ACL damage leads to an increased rotation range, with a subsequent decrease of the rotators' strength and increased joint instability. The patients examined showed a substantial level of thigh quadriceps atrophy - a typical symptom associated with an ACL rupture. Our findings indicate that the internal and external rotators in intact knees were stronger than the rotators in post-traumatic knees (p < 0.05). Conclusions. The analysis of the torque of the shank rotating muscles at two knee joint flexion angles was an attempt to proceed with a laboratory diagnosis of the condition of the motor system in 40 patients following severe trauma (such as the ACL rupture of the right knee) prior to surgical intervention, and, in a longer perspective, after treatment completion. The results obtained will supposedly be useful as indicators for future rehabilitation pathways, and of the condition of the motor system following treatment completion.

Intra-articular morphine versus bupivacaine for knee motion among patients with osteoarthritis: randomized double-blind clinical trial.

Osteoarthritis causes pain and disability in a high percentage of elderly people. The aim of the present study was to assess the efficacy of intra-articular morphine and bupivacaine on the joint flexion and extension angles of patients with knee osteoarthritis. A randomized double-blind study was performed at a pain clinic of Universidade Federal de São Paulo. Thirty-nine patients with pain for more than three months, of intensity greater than three on a numerical scale (zero to 10), were included. G1 patients received 1 mg (1 ml) of morphine diluted in 9 ml of saline, intra-articularly, and G2 patients received 25 mg (10 ml) of 0.25% bupivacaine without epinephrine. Pain was assessed on a numerical scale and knee flexion and extension angles were measured after administration of the drugs at rest and during movement. The total amount of analgesic supplementation using 500 mg doses of paracetamol was also determined. No significant difference in pain intensity was observed between G1 and G2. Significant decreases in pain at rest and during movement and significant increases in mean flexion and extension angles were observed in both groups, with no significant difference between the two groups. The mean total amount of paracetamol used over a seven-day period was 3578 mg in G1 and 5333 mg in G2 (P = 0.2355; Mann-Whitney test). The analgesic effects of 1 mg of morphine and 25 mg of 0.25% bupivacaine were similar among patients with osteoarthritis of the knee.

The roll-glide value as a motion parameter of biological curved joints exemplified by the human knee joint

By means of the so-called roll-gliding number lambda complex motion patterns between the moving parts of biological joints can easily be described as to being composed either of a more rolling motion with only minor wear or of a more gliding motion with a higher amount of wear at the joint surfaces. Thus the roll-gliding number, the magnitude of which depends on the angle of joint flexion, offers also an indirect approach to evaluate dynamic disorders of the function of such joints. As an example a description is given of the numerical calculation of the roll-gliding number for the medial and the lateral half of the human knee joint a various angles of joint flexion.

Influence of elbow flexion angle on mobilization of the proximal radio-ulnar joint: A motion analysis using cadaver specimens

The purpose of this study was to determine the most effective elbow joint flexion angle for mobilization of the proximal radio-ulnar joint. Five fresh-frozen cadaveric elbows were used to measure displacement of the radial head in the antero-medial and postero-lateral directions by traction force of 2 kgf and 4 kgf, respectively. Simulation of the gliding of the proximal radio-ulnar joint was performed at four elbow flexion angles (0°, 30°, 60°, 90°). Data obtained from those flexion angles were compared using one-way repeated measures analysis of variance. Radial head displacement at 60° and 90° during antero-medial gliding were significantly greater than those at 0° and 30° ( p < 0.05) There were no significant differences in radial head displacement among four elbow flexion angles during postero-lateral gliding at 2 kgf and 4 kgf. Our findings suggest that proximal radio-ulnar joint mobilization in the antero-medial direction can be performed effectively at 60° and 90° elbow flexion.

축구 인스텝 킥의 하지관절 움직임과 해부학적 각운동 분석

본 연구는 축구 인스텝 킥에서 지지 다리의 후족각과 차는 다리의 해부학적 회전 운동의 자료들을 분석해서 다음과 같은 결론을 얻었다. 발목 관절에서의 외반각은 지지발의 접지 이전에 최대 피크에 도달했으며, 저측 굴곡은 그룹 간 최대 피크의 타이밍에서 약간의 차이가 나타났다. 지지발의 접지 시 후족의 굴곡각은 그룹 간 통계적으로 유의한 차이가 났으며, 지지발의 접지 시 하퇴의 운동은 그룹 간 유의한 차이가 없었다. 접지 이전에 이미 하퇴를 후방으로 많이 기울였으며, 임팩트 순간 하퇴의 좌우 기울기는 22도였다. 차는 다리 고관절의 굴곡/신전은 지지발의 접지 시 최대 피크에 이르렀으며, 이 순간 고관절의 최대 신전각은 30도 이상으로 나타났다. 차는 다리 무릎 관절의 굴곡각은 접지와 임팩트의 사이에 최대로 굽혔으며, 족관절의 최대 저측 굴곡각과 최대 외번각은 그룹 간 유의한 차이는 나지 않은 반면, 최대 외측 회전각은 유의한 차이가 났다. This study analyzed the rear foot angle of the supporting leg and the anatomical rotation angle of the kicking angle in soccer instep kick and drew conclusions as follows. When the supporting leg was landing on the ground, the valgus angle of the ankle joint reached the maximum peak, and plantar flexion was slightly different in the timing of the maximum peak between the two groups. The flexion angle of the rear foot was statistically significantly different between the two groups, and the movement of the crus on the landing of the supporting foot did not show a statistically significant difference between the groups. The crus leaned backward most before the impact, and the side to side gradient of the crus on impact was <TEX>$22^{\circ}$</TEX>. The flexion/extension of the hip joint of the kicking leg reached the maximum peak when the supporting foot was landing on the ground, and at the moment, the maximum extension angle of the hip joint was over <TEX>$30^{\circ}$</TEX>. The flexion angle of the knee joint of the kicking leg was largest after landing. While the maximum plantar flexion angle and maximum valgus angle of the ankle joint were not significantly different between the two groups, the maximum external rotation angle was significantly different.

Neuromuscular and biomechanical landing performance subsequent to ipsilateral semitendinosus and gracilis autograft anterior cruciate ligament reconstruction

The hamstrings musculature is a vital component of an intricate dynamic knee joint restraint mechanism. However, there is evidence based on research studies suggesting potential deficits to this complex mechanism due to donor site morbidity resulting from harvest of the ipsilateral semitendinosus and gracilis autograft (ISGA) for anterior cruciate ligament reconstruction (ACLR). The purpose of this retrospective research study was to investigate the effects of ISGA ACLR on neuromuscular and biomechanical performance during a single-leg vertical drop landing (VDL), a functional task and associated mechanism of anterior cruciate ligament disruption during physical activity. Fourteen physically active participants 22.5 +/- 4.1 years of age and 21.4 +/- 10.7 months post ISGA ACLR underwent bilateral neuromuscular, biomechanical and isokinetic strength and endurance evaluations matched to 14 control participants by sex, age, height and mass. Kinetic and kinematic data was obtained with 3-D motion analyses utilizing inverse dynamics while performing single-leg VDLs from a height of 30 cm. Integrated surface electromyography (SEMG) assessments of the quadriceps, hamstrings and gastrocnemius musculature were also conducted. Additionally, knee joint flexion strength (60 degrees s(-1)) and endurance (240 degrees s(-1)) measurements were tested via isokinetic dynamometry. No significant differences existed in hip and net summated extensor moments within or between groups. The ISGA ACLR participants recorded significantly decreased peak vertical ground reaction force (VGRF) landing upon the involved lower extremity compared to uninvolved (P = 0.028) and matched (P < 0.0001) controls. Participants having undergone ISGA ACLR also displayed greater peak hip joint flexion angles landing upon the involved lower extremity compared to uninvolved (P = 0.020) and matched (P = 0.026) controls at initial ground contact. The ISGA ACLR group furthermore exhibited increased peak hip joint flexion angles landing upon the involved lower extremity compared to uninvolved (P = 0.019) and matched (P = 0.007) controls at peak VGRF. Moreover, ISGA ALCR participants demonstrated greater peak knee (P = 0.005) and ankle (P = 0.017) joint flexion angles when landing upon the involved lower extremity compared to the matched control at peak VGRF. The ISGA ACLR group produced significantly greater reactive muscle activation of the vastus medialis (P = 0.013), vastus lateralis (P = 0.008) and medial hamstrings (P = 0.024) in the involved lower extremity compared to the matched control. The ISGA ACLR participants also exhibited greater preparatory (P = 0.033) and reactive (P = 0.022) co-contraction muscle activity of the quadriceps and hamstrings landing upon the involved lower extremity compared to the matched control. In addition, the ISGA ACLR group produced significantly less preparatory (P = 0.005) and reactive (P = 0.010) muscle activation of the gastrocnemius in the involved lower extremity compared to the uninvolved control. No significant differences were present in hamstrings muscular strength and endurance. Harvest of the ISGA for purposes of ACLR does not appear to result in significant neuromuscular, biomechanical or strength and endurance deficiencies due to donor site morbidity. However, it is evident that this specific population exhibits unique neuromuscular and biomechanical adaptations aimed to stabilize the knee previously subjected to ACL trauma and safeguard the ISGA ACLR joint. Co-contraction of quadriceps and hamstrings as well as inhibition of gastrocnemius muscle activation may serve to moderate excessive loads exposed to the intra-articular ISGA during single-leg VDLs. Furthermore, greater muscle activation of the hamstrings in conjunction with increased peak hip, knee and ankle joint flexion angles may assist in enhancing acceptance of VGRF transferred through the kinetic chain following single-leg VDLs.

In vivo changes in the human patellar tendon moment arm length with different modes and intensities of muscle contraction

The purpose of this study was to examine the effect of different muscle contraction modes and intensities on patellar tendon moment arm length ( d PT ) . Five men performed isokinetic concentric, eccentric and passive knee extensions at an angular velocity of 60 deg/s and six men performed gradually increasing to maximum effort isometric muscle contractions at 90 ∘ and 20 ∘ of knee flexion. During the tests, lateral X-ray fluoroscopy imaging was used to scan the knee joint. The d PT differences between the passive state and the isokinetic concentric and extension were quantified at 15 ∘ intervals of knee joint flexion angle. Furthermore, the changes of the d PT as a function of the isometric muscle contraction intensities were determined during the isometric knee extension at 90 ∘ and 20 ∘ of knee joint flexion. Muscle contraction-induced changes in knee joint flexion angle during the isometric muscle contraction were also taken into account for the d PT measurements. During the two isometric knee extensions, d PT increased from rest to maximum voluntary muscle contraction (MVC) by 14–15%. However, when changes in knee joint flexion angle induced by the muscle contraction were taken into account, d PT during MVC increased by 6–26% compared with rest. Moreover, d PT increased during concentric and eccentric knee extension by 3–15%, depending on knee flexion angle, compared with passive knee extension. These findings have important implications for estimating musculoskeletal loads using modelling under static and dynamic conditions.

Effect of tibial tubercle elevation on biomechanics of the entire knee joint under muscle loads

Anterior elevation of the tibial tubercle, known as Maquet procedure, is performed to reduce excessive patellofemoral contact stresses in knee joints with patellofemoral osteoarthritis and anterior pain. Previous investigations, however, have entirely focused on the likely effect of tibial tubercle elevation procedure on biomechanics of contact at the patellofemoral joint with no attention what-so-ever to associated alterations in biomechanics of the tibiofemoral joint. Using a validated 3D nonlinear finite element model of the entire knee joint, the effect of 1.25 cm and 2.5 cm tubercle elevations on the entire knee joint biomechanics was investigated under constant quadriceps load of 411 N alone or combined with hamstrings co-activation of 205.5 N under joint angles of 0-90 degrees. Results confirm the effectiveness of this procedure in reducing patellofemoral contact forces, especially at smaller flexion angles. Maximum contact stress substantially decreased at full extension but increased at 90 degrees. Substantial effects of tuberosity elevation on tibial kinematics, cruciate ligament forces, tibiofemoral contact forces and extensor lever arm were found. The posterior cruciate ligament and tibiofemoral contact forces at larger flexion angles considerably increased whereas the anterior cruciate ligament and tibiofemoral contact forces at near full extension angles decreased. Overall, the extent of changes depended on the magnitude of anterior elevation, joint flexion angle and loading considered. Biomechanics of the tibiofemoral joint were significantly influenced by tibial tubercle elevation. Current results advocate the need for an integral view of the entire knee joint in management of various joint disorders rather than a view in which each component is considered and treated in isolation with no due attention to perturbations caused and associated consequences.

KINEMATIC TRAJECTORIES WHILE WALKING WITHIN THE LOKOMAT ROBOTIC GAIT-ORTHOSIS

Purpose/Hypothesis: To compare the kinematic patterns of subjects walking in the Lokomat robotic gait-orthosis with those demonstrated during treadmill walking, and to quantify the amount of relative movement inside the device. The field of neurorehabilitation has been adopting robotic devices to help deliver mass-practice therapy to individuals with various types of neurological disorders (Hidler et al, 2005 for review). The Lokomat (Hocoma AG, Volketswil Switzerland) is the most widely adopted robotic system used for gait training. Previous studies have quantified changes in muscle activation pattern when subjects walk in the Lokomat to those on a treadmill (Hidler and Wall, 2005). No studies to date have tracked the kinematic patterns of the legs inside the Lokomat. Number of Subjects: 6 healthy subjects (4 male, 2 female) participated in the study. Materials/Methods: A Codamotion (Charnwood Dynamics, UK) motion analysis system was used to track the kinematic patterns of the subject's pelvis and legs, and the robotic limbs of the Lokomat. Marker clusters were placed on each limb segment and tracked at 100 Hz. Subjects walked on the treadmill with and without the Lokomat at four randomly selected walking speeds (2.0, 2.4, 2.8, 3.2 km/hr). For all trials, subject and Lokomat marker positions and ground reaction forces were recorded for 30-second step sequences. A number of kinematic metrics were compared between the two modalities using a one sample t-test (alpha = 0.05), including ankle, knee, and hip range of motion, maximum and minimum joint flexion and extension angles, and the point in the gait cycle each occurred. The relative knee and hip movement between the subject's and Lokomat's joint centers in both the frontal and sagittal planes were quantified. Results: While some subjects experienced slight differences in kinematic patterns, there were no significant differences in any of the metrics computed for all subjects across walking modalities. Despite there being no differences in sagittal joint angular patterns, the side to side motion of the hip in the medial-lateral plane was significantly less in the Lokomat than on the treadmill, sometimes restricted by as much as 75%. The relative movement of subjects' legs inside the Lokomat was substantial, where the variability in the knee joint center in the sagittal plane was approximately 1 cm while deviations exceeded 2 cm for the hip joint. Conclusions: With proper setup, the Lokomat gait patterns mimic those utilized during treadmill ambulation. Differences in the amount of medial-lateral hip motion can be attributed to the reduced degrees of freedom the Lokomat places on the subject. Clinical Relevance: The finding that there is significant movement of the subject's legs inside the Lokomat is important clinically, as a variable step pattern has been shown to be a more effective gait training strategy than one which forces the same kinematic pattern across successive steps (Cai et al., 2005).

Angle between the patellar ligament and tibial plateau in dogs with partial rupture of the cranial cruciate ligament

To measure the angles between the patellar ligament and the tibial plateau and between the patellar ligament and the common tangent at the tibiofemoral contact point (TFCP) in stifle joints of dogs with partial rupture of the cranial cruciate ligament (CrCL) for comparison with data obtained for stifle joints in dogs with intact CrCLs. 60 stifle joints of 54 dogs with surgically confirmed partial CrCL rupture. Mediolateral radiographic views of the stifle joints were obtained, and the angles between the patellar ligament and the conventionally defined tibial plateau (angle gamma) and between the patellar ligament and the common tangent to the TFCP (angle alpha) were measured at incidental stifle joint flexion (angle beta) by 2 independent observers. Data underwent linear regression analysis and were compared with findings in joints of dogs without degenerative joint disease. In stifle joints of dogs with a partial rupture of the CrCL, angles gamma and alpha were 5 degrees and 2 degrees larger than each corresponding angle in healthy canine joints. At 100 degrees of flexion, the patellar ligament was perpendicular to the conventionally defined tibial plateau. At 110 degrees of flexion, the patellar ligament was perpendicular to the common tangent at the TFCP. In dogs, stifle joints with partially ruptured CrCLs have marginally larger angles between the patellar ligament and the tibial plateau, compared with joints with intact CrCLs; at equivalent angles of flexion, comparatively greater shear force affects the CrCLs in stifle joints with partial CrCL ruptures.

Knee Joint Angle at the Time of Adjustment to Submaximal Jumping in Healthy Men

We examined the correlation between jump distance and the maximum flexion angle of the knee joint during jumping to evaluate whether healthy men adjust to jump distance by changing the angle of the knee joint. Fourteen subjects jumped 3 times with their eyes closed to each of what they thought was 25%, 50%, and 75% of their maximum jump distance, a total of 9 jumps for both the vertical and standing broad jump. We measured the knee joint flexion angle at the time of the motion and examined the correlation between jump distance and knee joint flexion angle. The results show a relationship between jump distance and knee joint flexion angle for both the vertical and standing broad jump. We determined that jump distance is controlled by knee joint flexion angle in healthy men. Thus, a factor of jump control was clarified in this study.

A robot‐assisted study of intrinsic muscle regulation on proximal interphalangeal joint stiffness by varying metacarpophalangeal joint position

The tightness of intrinsic hand muscles is a common cause of finger joint stiffness. The purposes of this study were to develop a robot-assisted methodology to obtain torque-angle data of a finger joint, and to investigate the regulation of the intrinsic muscles on finger joint stiffness. Our robot system features the integration of a low payload robot arm, a controller, and a force/torque transducer. The system provided highly reproducible torque-angle curves. Torque-angle data of the proximal interphalangeal joint with the metacarpophalangeal joint at 0 and 60 degrees were obtained from eight asymptomatic hands. The torque-angle curve shifted with the position of the metacarpophalangeal joint. As the metacarpophalangeal joint flexion angle changed from 60 to 0 degrees, the equilibrium of the proximal interphalangeal joint increased more than 20 degrees, and joint stiffness increased more than 50%. The dependence of the stiffness of the proximal interphalangeal joint on metacarpophalangeal joint position supports the regulatory role of the intrinsic muscles on finger joint mechanics. This regulatory mechanics is likely amplified in hands with intrinsic muscle tightness, justifying the commonly used Bunnell Intrinsic Tightness Test.

인라인 스케이트(Inline Skate) 힐 브레이크(Heel-Brake) 정지에 관한 운동학적 분석

This study has a purpose on contributing to apprehend safe and right way to stop to the inline skate beginners and to the instructors who teaches line skating on the basis for the result of the kinematical analysis on Heel brake stop movement of the inline skate, focusing on the displacement on COG, angle displacement of ankle joint, angle displacement of knee joint, angle displacement of hip joint, using a 3D image method by DLT. To achieve this goal, we analysed the kinematical factor of the 3 well-trained inline skating instructors and obtained the following results. 1. During the movement of heel-brake stop, when strong power was given to a stable and balanced stop and the lower limbs, if the physical centroid is lowered the stability increases, and if it is placed high from the base surface, as the stability decreases compared to the case of low physical centroid, we should make a stop by placing a physical centroid in the base surface and lowering the hight of physical centroid. 2. To make a stable and balanced stop and to provide a strong power to the lower limbs, it is advisable to make a stop by decreasing an angle displacement of ankle joint during a "down" movement. In case of the left ankle joint, in all events and phases the dorsiflexion angle showed a decrease. Nevertheless, in the case of the right ankle joint, the dorsiflexion angle shows an increase after a slight decrease. The dorsiflexion angle displacement of ankle joint can be diminished because of the brake pad of the rear axis frame of the right side inline skate by raising a toe, but cannot be more decreased if certain degree of an angle is made by a brake pad touching a ground surface. To provide a power to a brake pad, it is recommended to place a power by lowering a posture making the dorsiflexion angle of the left ankle joint relatively smaller than that of the right ankle. 3. To make a stable and balanced stop and to add a power to a brake pad, the power must be given to the lower limbs in lowering the hight of physical centroid. For this, it is recommended to make a down movement by decreasing the flexion angle of a knee joint and it is necessary to make a down movement by a regular decrease of the angle displacement of knee joint rather than a swift down movement in every event and phase. 4. The right angle displacement of hip joint is made by lowering vertically the hight of physical centroid as leaning slightly forward. If too narrow angle displacement of hip joint is made by leaning forward too much, the balance is lost during the stop by placing the center in front. To make a stable and balance stop and to place a strong power to the lower limbs, it is recommendable to make a narrow angle by lower the hip joint angle. However, excessive leaning of the upper body to make the angle too narrow, can cause an instable stop and loss of physical centroid. After this study, it is considered to assist the kinematical understanding during the heel brake stop movement of the inline skate, and, to present basic data in learning a method of stable and balanced stop for the inline skating beginners or for the inline skate instructors in the present situation of the complete absence of the study in inline skating.