• Korean Journal of Applied Biomechanics
• /
• v.22 no.3
• /
• pp.315-324
• /
• 2012

The purpose of current study was to investigate the effects of the heights on the lower extremities, torso and neck segments for energy dissipation during single-leg drop landing from different heights. Twenty eight young healthy male subjects(age: $23.21{\pm}1.66yr$, height: $176.03{\pm}4.22cm$, weight: $68.93{\pm}5.36kg$) were participated in this study. The subjects performed the single-leg drop landing from the various height(30, 45 & 60 cm). Force plates and motion-capture system were used to capture ground reaction force and kinematics data, respectively. The results were as follows. First, the ROM at the ankle, knee, hip and trunk was increased with the increased heights but the ROM at the neck was increased in the 60cm. Second, the angular velocity, moment and eccentric work at the ankle, knee, hip, trunk, and neck was increased with the increased heights. Third, the contribution to total work at the knee joint was not significantly different, while the ankle joint rate was decreased and hip and neck rate was increased in the 60cm, and trunk rate was increased with the increased heights. Lastly, the increase in landing height was able to augment the level of energy dissipation not only at the lower extremities but also at the trunk and neck. The findings showed that drop landing affect trunk and neck with lower extremity joints. Therefore, we need to consider that trunk and neck strengthening including stability should be added to reduce sports injury during prevention training.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
• /
• v.5 no.1
• /
• pp.39-51
• /
• 1999

Background and Purpose. Objective measurements of hamstring muscle length are needed to quantify baseline limitations and to document the effectiveness of therapeutic interventions. Several indirect clinical tests for measuring hamstring muscle length are available, but influence of their test procedure is not well documented. The purpose of this study were 1) to describe hamstring muscle length as reflected by use of six tests(active straight leg raising(ASLR), passive straight leg raising(PSLR), passive straight leg raising with the lower back flat(PSLRB), active knee extension(AKE), passive knee extension(PKE), hip joint angle(HJA). 2) to examine the correlation among the tests. Subjects, Sixty subjects(30 men. 30 women) ranging in age from 18 to 25 years(mean 20.2 years) and with no limitation hamstring flexibility and no neurological and orthopedical problems. Methods. All subjects performed six tests. A inclinometer was used to determine the end point of range of motion. HJA was measured using an inclinometer placed over the sacrum. PSLRB were tested PSLR with the low back flat and the opposite thigh slightly flexed and support on pillows. Results, A mean ASLR value of 85.9 degrees, PSLR value of 99.9 degrees, PSLRB value of 109.8 degrees, AKE value of 77.2 degrees PKE value of 83.1 degrees and HJA value of 73.0 degrees were obtained for all subjects. A dependent t-test showed significant difference between the angles of ASLR and PSLR(p<0.001). There was a significant difference between the angles of PSLR and PSLRB(p<0.001). There was a significant difference between the angles of AKE and PKE(p<0.001). The highest correlation was between PSLR and PSLRB(r=0.915, p<0.001). All SLR tests were significants related(p<0.001), as well as AKE and PKE(p<0.001). The lowest correlation was between PKE and HJA(r=0.171. p>0.05). Conclusion and Discussion. The results indicated that the hip flexion angles for ASLR, PSLR and PSLRB were a difference, and the knee extension angles for AKE and PKE were a difference.

• Korean Journal of Applied Biomechanics
• /
• v.18 no.1
• /
• pp.203-212
• /
• 2008

The purpose of this study is to propose appropriate model for 3 staged Didimsae movement to Jajinmori rhythm and to provide information for ideal foot step movements. For the locational change of body center, the height of body center is lowered at the moment of forward step and during forward intersection of the feet, forward direction linear motion is converted to vertical motion to maintain stability. Speed change of body center reduces flow of body on step forward moment and controls rapid forward movement for stabled movement and position when preventing fast forward horizontal direction movement of centroid speed while knee joint and foot joint are vertically risen for heel bone contacts the ground. For angle changes of joints, in order to prevent hyperextension of lower leg, hip joint is extended and knee joint is curved to secure stability of movement for smooth curves and extension. When centroid of foot joint is moved from top of the feet to whole foot sole and when left foot makes dorsal curve, stabled movement is accomplished.

• Korean Journal of Applied Biomechanics
• /
• v.26 no.1
• /
• pp.71-82
• /
• 2016

Objective: The purpose of this study was to investigate kinematic comparisons of Tsukahara vault in gymnastics between a top-level athlete and sublevel collegiate athletes in order to obtain information on key biomechanical points for successful Tsukahara vaults. Methods: An Olympic gold medalist (height, 160 cm; weight, 52 kg; age, 25 years) and five sublevel collegiate gymnasts (height, $168.2{\pm}3.4cm$; weight, $59.6{\pm}3.1kg$; age, $23.2{\pm}1.6years$) participated in this study. They repeatedly performed Tsukahara vaults including one somersault. Fourteen motion-capturing cameras were used to collect the trajectories of 26 body markers during Tsukahara vaults. Event time, displacement and velocity of the center of mass, joint angles, the distance between the two hands on the horse, and averaged horizontal and vertical impact forces were calculated and compared. Results: The top-level athlete showed a larger range of motion (ROM) of the hip and knee joints compared to sublevel collegiate athletes during board contact. During horse contact, the top-level athlete had a narrow distance between the two hands with extended elbows and shoulders in order to produce a strong blocking force from the horse with a shorter contact time. At the moment of horse take-off, reactive hip extension of the top-level athlete enhanced propulsive take-off velocity and hip posture during post-flight phase. Conclusion: Even though a high velocity of the center of mass is important, the posture and interactive action during horse contact is crucial to post-flight performance and the advanced performance of Tsukahara vaults.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
• /
• v.15 no.2
• /
• pp.63-68
• /
• 2009

Purpose : The purpose of this study was to investigate the effect of tensor fasciae latae length on the rotation of pelvis during one leg stance. Methods : 41 healthy adults participated in this study. The movement of the pelvis and trunk was measured using 3-dimensional motion analyzer, during one leg stance. The movement of the pelvis and trunk was collected lateral shift, rotation, side bending, and flexion-extension. Tensor fasciae latae length of subjects was measured in sidelying positon with neutral position of hip joint and flexion $90^{\circ}$ of knee. Also, the range of motion of hip exteral and interal rotaion were measured in prone position wih lexion $90^{\circ}$ of knee. The subjects were separated 2 groups that more pelvic rotation group(n=15) and less pelvic rotation group(n=15) according to the degree of pelvic rotation. Results : The more pelvic rotation group was showed significantly higher in the ROM of hip external rotation than less pelvic rotation group(p<0.05). The difference of tensor fasciae latae length not showed significant difference between groups. During one leg stance, The movement of the shifting and flexion-extension of trunk and pelvis were not showed significant difference. But the side bending and the rotation of pelvis and trunk showed significant difference between groups. Conclusion : The difference of tensor fasciae latae length not showed significantly in more pelvic rotation group and less pelvic rotation group. But, this study suggests that the pelvis instability brings the instability of the trunk during one leg stance.

• Journal of the Korean Society of Physical Medicine
• /
• v.13 no.4
• /
• pp.85-94
• /
• 2018

PURPOSE: This study was conducted to determine the effects of therapeutic exercise on range of motion (ROM), the manual muscle test (MMT), functional movement screen (FMS) and radiological evaluation in a youth football player with football-specific anterior pelvic tilt (APT). METHODS: The subject of this case report was a 12-year-old youth football player, who presented with football-specific APT. Therapeutic exercise consisted of hamstring stretch, prone hip extension, abdominal crunch, bridging with isometric hip abduction, plank exercise with posterior tilt and posterior pelvic tilting exercise using a swiss-ball for 40 min/day, twice a week for 8-weeks. ROM, MMT, FMS (deep squat, hurdle step, inline lunge, shoulder mobility, active straight-leg raise, rotary stability and trunk stability push-up) and radiographs (lumbar lordotic and sacral horizontal angle) were analyzed before and after week 8 of therapeutic exercise. RESULTS: The ROM, MMT, and FMS increased and the lumbar lordotic angle and sacral horizontal angle improved after 8-weeks of therapeutic exercise. CONCLUSION: The results of this case report suggest that therapeutic exercise improves ROM, MMT and radiography associated parameters in youth football players with football-specific APT. These findings have clinical implications for therapeutic exercise in youth football players with football-specific APT.

• Journal of the Korean Society of Physical Medicine
• /
• v.16 no.4
• /
• pp.1-11
• /
• 2021

PURPOSE: Lumbosacral orthosis (LSO) is often used to help manage low back pain because it is economical and effective. This study examined the effects of flexible and semirigid LSOs on the lower-limb joint angles in walking in patients with chronic low back pain. METHODS: The effects of the lumbosacral orthosis during gait on the sagittal, frontal, horizontal planes and the change in lower limb angle were examined in fourteen chronic low back pain patients who walked without wearing a LSO, wearing a flexible LSO, and wearing a semirigid LSO in random order for three-dimensional motion analysis. RESULTS: The flexion of the hip and knee joints decreased more significantly during walking with an LSO than without one. The genu valgum angles were reduced in the stance phase more during walking with an LSO than without one. The external rotation of the knee joints in the stance phase increased more during walking with an LSO than without one. CONCLUSION: The angles of the lower-limb joints of patients with chronic low back pain are affected by walking with an LSO, and the effects increased as the LSO stiffened.

• PNF and Movement
• /
• v.20 no.1
• /
• pp.19-29
• /
• 2022

Purpose: The purpose of this study was to analyze the gait patterns of adults with intellectual disability and healthy adults based on collected kinematic data on the lower extremities and to investigate the gait patterns of intellectually disabled people by comparing the differences between the two groups. Methods: The participants were divided into in one group of healthy adults (n = 9) and one group with mild intellectual disabilities (n = 9). 3D motion analysis (Myomotion) was used to collect kinematic data from each group while the participants walked 3 times over 10 m. As a statistical method, each group's kinematic data during walking was analyzed and compared using an independent sample t-test. Results: Comparing the kinematic data of the lower extremities during walking between the group with mild intellectual disability and the healthy group, there were significant differences between the two groups in the hip and ankle joints in the stance and swing phases. Conclusion: The analysis suggests that people with intellectual disabilities have kinematic differences compared with healthy people. Based on the results of this study, it is necessary to conduct further research on rehabilitation programs for joint stabilization, exercise for increasing joint range of motion, muscle strengthening exercise, and proprioception training for people with intellectual disabilities with insufficient physical function.

• The Journal of Korean Physical Therapy
• /
• v.25 no.6
• /
• pp.399-404
• /
• 2013

Purpose: To investigate the effects of initiation side on gait symmetry in the chronic stroke patients. Methods: Twenty one patients with independent gait after stroke were divided into the paretic-leg gait initiation group (PLI) and the nonparetic-leg gait initiation group (NPLI). The symmetry ratio (SR) was calculated from of the spatiotemoral and kinematic parameter which measured by 3D motion analysis. Results: In the spatiotemporal variables, SR-step length and SR-velocity was significantly different between groups (p<0.05). In the kinematic variables, SR-TOAA and SR-SwPAA of the hip joint was significantly different between groups (p<0.05). Conclusion: We suggest that the initiating leg may influence on the gait symmetry of stroke patient These results will be a helpful reference in hemiplegic gait training or intervention.

• Korean Journal of Applied Biomechanics
• /
• v.16 no.2
• /
• pp.153-163
• /
• 2006

The purpose of this research was to analyze kinematic variables that appear during the instep shooting motion of female high school soccer players according to the angle of approach to find effective shooting motions. For this experiment, 5 female high school soccer players from the K city were participated in this study as the subject group, and as a through comparison and analysis of the resulting numbers of the variables, we came to the following conclusions. 1) Stride length and stride length/lower extremity length increased as the angle of approach increased. 2) As for C.O.G movement displacement, it was highest at an approach angle of $90^{\circ}$ during Right Foot Contact, at $135^{\circ}$ during Left Foot Contact, at $0^{\circ}$ during Rigth Toe Top, at $45^{\circ}$ during Impact, and at $0^{\circ}$ during Follow through. 3) The time required for each phase was longest at APP and shortest at BSP. The time required increased a little as the angle of approach increased, and the total time required also increased as the angle of approach increased. 4) The angle of the ankle joint was largest at an approach angle of $45^{\circ}$ for all events except Right Foot Contact. 5) The angle of the knee joint was largest at an approach angle of $135^{\circ}$ during Right Foot Contact, at $0^{\circ}$ during Left Foot Contact, at $45^{\circ}$ during Right Toe Top, at $135^{\circ}$ during Impact, and at $90^{\circ}$ during Follow through. 6) The angle of the hip joint was largest at an approach angle of $90^{\circ}$ during Right Foot Contact, at$0^{\circ}$ during Left Foot Contact, at $0^{\circ}$ during Right Toe Top, at $90^{\circ}$ during Impact, and at $0^{\circ}$ during Follow through.