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Maintaining balance while performing “Hakdariseogi” in Taekwondo, which involves standing on one leg, is a critical aspect of the Poomsae competition. The purpose of this study was to investigate the effect of proprioceptive training and lower-limb muscular strength training on the balance of Taekwondo Poomsae athletes over a 6-week period. Thirty Taekwondo Poomsae athletes were randomly assigned to three groups, namely, a proprioception training group, a lower-limb muscular strength training group, and a control group. Biomechanics data were collected using eight infrared cameras (Qualysis, Sweden) at 200 Hz and a force plate (Kistler, Switzerland) at 2,000 Hz while the participants performed “Hakdariseogi” before and after the 6-week intervention. Balance and stability variables were calculated using customized MATLAB R2014b software (Mathworks, Inc., USA). The medio-lateral (M/L) center of pressure (CoP) range, M/L CoP mean velocity, antero-posterior (A/P) CoP range, A/P CoP mean velocity, and the vertical ground reaction torque after the training were reduced at P1 in the PG groups (p < 0.05). A decrease in the A/P CoP range, A/P CoP mean velocity, and vertical ground reaction torque after the training were observed at P2 in the PG and SG groups (p < 0.05). The PG exhibited a smaller A/P CoP range and A/P CoP mean velocity, in comparison to CG (p < 0.05). The A/P CoP position at P1 was negatively correlated with the vertical ground reaction torque, A/P CoP range, and A/P CoP mean velocity at P2(r = -0.438, r = -0.626, r = -0.638). Based on the above results, this study determined that both proprioception training and lower-extremity muscle strength training resulted in an improvement of athletic performance. It was also desirable to move the CoP position through conscious effort forward at P2 in order to maintain the crane stance without sway.

Footwear needs to properly protect the lower extremities including the foot, by absorbing excessive impact during movement. The trajectory of the center of pressure during walking indicates that th...

Objective: The purpose of this study was to investigate kinematic differences in back pike somersault in platform diving according to skill level and to apply the findings to improve performance. Method: Korean divers participating in this study were divided into a skilled group (age: 21.6±4.16 y, height: 1.68±0.03 m, weight: 62.0±3.94 kg, career: 12.6±5.13 y) and a less-skilled group (age: 20.6±2.7 y, height: 1.72±0.05 m, weight: 64.8±6.76 kg, career: 12.2±2.49 y) and an independent t-test was performed to analyze differences between groups at the moment of takeoff. Results: The two groups showed significant differences in displacement and velocity of center of mass (COM), takeoff angle, hip joint angle, knee joint angular velocity, and hip joint angular velocity at the takeoff (p

Objective: To investigate rotation movement of segment for performing each position and its effect on knee/hip angulation, COM inclination, and edging angle changes. Method: Twelve Alpine skiers (age: 25.8±4.8 years, height: 173.8±5.9 cm, weight: 71.4±7.4 kg, length of career: 9.9±4.6 years) participated in this study. Each skier was asked to perform counter-rotation, neutral, and rotation positions. Results: Shank and thigh were less rotated in the counter-rotation position than in other positions, whereas the trunk and pelvis were more counter-rotated (p

[Purpose] The purpose of this study was to examine the effect of modified Pilates exercise on cardiopulmonary function in chronic stroke patients. [Subjects and Methods] Twenty participants (age, 62.7 ± 7.3 years; height, 163.3 ± 8.5 cm; weight, 68.8 ± 10.3 kg) were recruited for this study, and randomly allocated to the modified Pilates exercise group (n=10) or the control group (n=10). Graded submaximal treadmill exercise test was used to examine the status of patients’ cardiopulmonary function, based on maximal oxygen intake, at the end of a patient’s exercise tolerance limit. [Results] The resting heart rates, maximal oxygen intake, and maximal oxygen intake per kilogram were significantly different after 8 weeks of modified Pilates exercise. In addition, these variables were also significantly different between the Pilates and control groups after 8 weeks. [Conclusion] This study has demonstrated that 8 weeks of modified Pilates exercise program can have a positive influence on patients with chronic stroke, potentially by enhancing the cardiopulmonary function, which may have positive implications for increasing their functional ability.

Objective: Gymnastics on rings needs a high level of muscle strength with balance ability for controlling the body. A study on a new balance training program is necessary for elite gymnasts. Therefore, the purpose of this study was to investigate the effects of an 8-week pilates core-muscle training on balance ability and asymmetry index of the L-sit on the rings in male elite gymnasts. Method: Ten elite gymnasts (age: 20.6±0.7 years, height: 169.9±4.9 cm, weight: 65.4±5.6 kg, career duration: 20.6±0.7 years), who are students at K-university, participated in this study. Results: First, the range of the COM tended to decrease in the anterior-posterior direction. Second, the left hip joint angle and knee extension and ankle dorsiflexion angles significantly increased after the pilates training. Third, the ROM also increased. Fourth, the symmetry value increased in the hip angle, while the symmetry index in all joints of the ROM decreased. As a result, the pilates core-muscle training influenced the static balance ability during the L-sit on the rings. Conclusion: Accordingly, the pilates core-muscle training is suitable in enhancing the basic balance ability in gymnastics on rings.

[Purpose] This study aimed to examine the effects of an 8-week modified Pilates program on the variability of inter-joint coordination in the elderly during walking. [Subjects and Methods] Twenty elderly participants with no recent history of orthopedic abnormalities (age, 67.9 ± 2.7 years; height, 163.7 ± 8.9 cm; weight, 67.1 ± 11.6 kg) were recruited for this study and randomly allocated to a modified Pilates exercise group or a control group. Three-dimensional motion analysis was performed on both groups to evaluate the effects of the Pilates exercise. [Results] There was no significant difference in the joint variability of the ankle, knee, and hip joints between the groups, both before training and after training. However, there was a significant increase in the hip-knee deviation phase value in the exercise group after the program was completed, and this increase was also significant when compared with that in the control group. [Conclusion] This study has demonstrated that an 8-week modified Pilates exercise program can have a positive impact on the gait of elderly participants, potentially by enhancing neuromuscular adjustment, which may have positive implications for reducing their fall risk.

The centre of pressure (COP) is an instantaneous point location of the ground reaction force. COP trajectory can provide useful information to characterize movement patterns or detect changes in fo...

Maintaining balance while performing “Hakdariseogi” in Taekwondo, which involves standing on one leg, is a critical aspect of the Poomsae competition. The purpose of this study was to investigate the effect of proprioceptive training and lower-limb muscular strength training on the balance of Taekwondo Poomsae athletes over a 6-week period. Thirty Taekwondo Poomsae athletes were randomly assigned to three groups, namely, a proprioception training group, a lower-limb muscular strength training group, and a control group. Biomechanics data were collected using eight infrared cameras (Qualysis, Sweden) at 200 Hz and a force plate (Kistler, Switzerland) at 2,000 Hz while the participants performed “Hakdariseogi” before and after the 6-week intervention. Balance and stability variables were calculated using customized MATLAB R2014b software (Mathworks, Inc., USA). The medio-lateral (M/L) center of pressure (CoP) range, M/L CoP mean velocity, antero-posterior (A/P) CoP range, A/P CoP mean velocity, and the vertical ground reaction torque after the training were reduced at P1 in the PG groups (p < 0.05). A decrease in the A/P CoP range, A/P CoP mean velocity, and vertical ground reaction torque after the training were observed at P2 in the PG and SG groups (p < 0.05). The PG exhibited a smaller A/P CoP range and A/P CoP mean velocity, in comparison to CG (p < 0.05). The A/P CoP position at P1 was negatively correlated with the vertical ground reaction torque, A/P CoP range, and A/P CoP mean velocity at P2(r = -0.438, r = -0.626, r = -0.638). Based on the above results, this study determined that both proprioception training and lower-extremity muscle strength training resulted in an improvement of athletic performance. It was also desirable to move the CoP position through conscious effort forward at P2 in order to maintain the crane stance without sway.

Background The rapid and repetitive badminton lunges would produce strenuous impact loading on the lower extremities of players and these loading are thought to be the contributing factors of chronic knee injuries. This study examined the impact loading characteristics in various groups of badminton athletes performing extreme lunges. Methods Fifty-two participants classified into male skilled, female skilled, male unskilled, and female unskilled groups performed badminton lunge with their maximum-effort. Shoe-ground kinematics, ground reaction forces, and knee moments were measured by using synchronised force platform and motion analysis system. A 2 (gender) x 2 (skill-level) factorial ANOVA was performed to determine the effects of different gender and different playing levels, as well as the interaction of two factors on all variables. Results Male athletes had faster approaching speed (male 3.87 and female 1.08 m/s), longer maximum lunge distance (male 1.47 and female 1.16 m), larger maximum (male 215.7 and female 121.65 BW/s) and mean loading rate (male 178.43 and female 81.77 BW/s) and larger peak knee flexion moment (male 0.75 and female 0.69) compared with female athletes (P < 0.001). Unskilled athletes exhibited smaller footstrike angle (skilled 45.78 and unskilled 32.35°), longer contact time (skilled 0.69 and unskilled 0.75 s), larger peak horizontal GRF (skilled 1.61 and unskilled 2.40 BW), smaller mean loading rate (skilled 150.15 and unskilled 110.05 BW/s) and larger peak knee flexion moment (P < .05; skilled 0.69 and unskilled 0.75 Nm/BW) than the skilled athletes. In addition, the interaction indicated greater peak GRF impact in female unskilled athletes compared with female skilled athletes (P < 0.001; female skilled 2.01 and female unskilled 2.95 BW), while there was no difference between male participants (P > 0.05; male skilled 2.19 and male unskilled 2.49 BW). Conclusions These data suggested that male athletes and/or unskilled athletes experience greater impact loading rates and peak knee flexion moment during lunge compared with female and skilled athletes, respectively. This may expose them to higher risk of overuse injuries. Furthermore, female unskilled athletes seemed to be more vulnerable to lower extremity injuries.

This study investigated whether an increase in the forefoot bending stiffness of a badminton shoe would positively affect agility, comfort and biomechanical variables during badminton-specific movements. Three shoe conditions with identical shoe upper and sole designs with different bending stiffness (Flexible, Regular and Stiff) were used. Elite male badminton players completed an agility test on a standard badminton court involving consecutive lunges in six directions, a comfort test performed by a pair of participants conducting a game-like practice trial and a biomechanics test involving a random assignment of consecutive right forward lunges. No significant differences were found in agility time and biomechanical variables among the three shoes. The players wearing the shoe with a flexible forefoot outsole demonstrated a decreased perception of comfort in the forefoot cushion compared to regular and stiffer conditions during the comfort test (p 0.05). The results suggested that the modification of forefoot bending stiffness would influence individual perception of comfort but would not influence performance and lower extremity kinematics during the tested badminton-specific tasks. It was concluded that an optimisation of forefoot structure and materials in badminton shoes should consider the individual's perception to maximise footwear comfort in performance.

[Purpose] The purpose of this study was to examine the fall-prevention effect of 12 weeks of aquatic training for the elderly using variables representative of the relationship between the trailing foot and an obstacle. [Subjects] Ten healthy elderly participants, who lived in C city, (age: 77.15±5.21 yrs, height: 149.87±3.54 cm, body mass: 57.44 ±6.74, and BMI: 25.58±2.98 kg/m(2)), participated in this study. [Methods] To determine the effect of 12 weeks' aquatic training, 3-D motion analysis with 7 infrared cameras and one force plate, was performed. [Results] TC, HC, MVHC, and CV significantly increased after intervention. For the all gait stability parameters, statistically significant training effects were found. [Conclusion] In conclusion, 12 weeks' aquatic exercise can help the elderly become more stable when crossing a height obstacle, which is the most frequent cause of falls by the elderly.

The purpose of this study was to investigate the training and detraining effects of a 8-week water exercise on lower extremities coordination during obstacle gait in the female elderly. Eight elderly participants (age: 76.58±4.97 yrs, height: 148.88±7.19 cm, body mass: 56.62±6.82 kg, and leg length: 82.36±2.98 cm), who stayed at the Seoul K welfare center, were recruited for this study. All participants had no history of orthopedic abnormality within the past 1 year and completed the aquatic exercise program which lasted for 8 weeks. To identify the training and detraining effect of 8 weeks of water exercise, a 3-D motion analysis with 7 infrared cameras and one force plate sampling frequency set at 100 Hz and 1,000 Hz, respectively, was performed. A two-way ANOVA was performed to find training and detraining effects among diferent obstacle heights. In this study significant level was set at .05. Significant training effects of LTS (lead foot thigh and shank) coordination in all obstacle height were found (p

【The purpose of this study was to investigate the effect of combined exercise on injury risk factors of lower extremity during landing. Ten sports talented athletes participated in this study. Sports talented athletes participated in a combined exercise (sports talented exercise, coordination) for 16 weeks. A three-dimensional motion analysis was performed using eight infrared cameras (sampling rate of 100 Hz), one force plate, and electromyography system (sampling rate of 1000 Hz) during landing. Kinetic, and kinematics analysis including average impulsive force, angle of lower extremity, vertical stiffness, onset of muscle activation were calculated by Matlab2009a software. Paired t-test was performed at alpha=.05. The average impulsive force in landing phase was not statistically significant (t=-.748, p=.474). The hip joint angle was more decreased in post test compared to pre test (E1: t=2.682, p=.025, E2: t=5.609, p=.000, E3: t=2.538, p=.032). The knee joint (E1: t=-.343, p=.739, E2: t=1.319, p=.220, E3: t=.589, p=.570) and ankle joint (E1: t=.081, p=.937, E2: t=.784, p=.453, E3: t=.392, p=.704) angle were tended to decrease after combined exercise. The vertical stiffness was tended to decrease after combined exercise (t=1.972, p=.080). Onset of quadriceps femoris (t=.698, p=.503) and medial gastocnemius (t=1.858, p=.096) were tended to be faster than biceps femoris (t=-.333, p=.747) after combined exercise. Although thses findings were not statistically significant except on a hip joint angle, risk factors of lower extremity such as joint angle, vertical stiffness and onset of quadriceps femoris, medial gastrocnemius were positively changed after the combined exercise but an additional training for improved onset of biceps femoris would be required in the future.】

This study investigated foot pressure patterns between experienced skiers and intermediate skiers during alpine skiing. Five experienced skiers and five intermediate skiers participated in this study. Foot pressure measurement system was used to measure vertical ground reaction force (vGRF) and contact area under the six plantar regions. Each participant was asked to perform basic parallel turns and carved turns on a 18o groomed slope. Each right turn was divided into the initiation phase, the steering phase 1 and 2. For the initiation phase of the basic parallel turns, significantly greater contact area was found on the LRF and RRF of the intermediate skiers (p

Basketball is a sport which places a considerable amount of stress on the lower extremities of players. Players perform an average of 70 jumps per game and may experience impact up to nine times bo...

The aim of this study was to investigate badminton smash and drop motion depends on player's level. To perform this study, ten male badminton players were participated: five skilled players (SG, age: 21.6±1.1 yrs, height: 181.4±6.8 cm, body mass: 72.4±5.7 kg, career: 11.2±1.1 yrs) and five less-skilled players (LSG, age: 21.2±1.1 yrs, height: 180.2±5.6 cm, body mass: 73.6±6.7 kg, career: 10.6±0.9 yrs). Three-dimensional motion analysis with 7 infrared cameras was performed with a sampling frequency as 200 Hz. Player's swing motion was divided into four events: starting motion (E1), backswing (E2), impact (E3), following (E4). For all upper joints, LSG showed greater angle differences between drop and smash motions than that of SG at E3 (p

The purpose of this study was to provide a fundamental information for enhancing 110m hurdlers' perfor- mance through conducting comparative biomechanical analysis between Skilled Group(SG) and Less- Skilled Group(LSG) those who are not in the first section of 110m hurdles. To persue the purpose of this study, total of 10 hurdlers participated. Then they were divided into two groups; SG: five hurdlers who have won awards with 14-second range at 2010 national track and field event, and LSG: five hudlers who did not win any awards with 15-second range. Three-dimensional motion analysis with 12 infrared cameras(Oqus 300, Qualisys) and 1 force plate(Type 9286AA, Kistler) was performed. From this study following conclu- sions were obtained. 1) For the overall runtime, SG revealed faster elapsed time than that of LSG. 2) At E4, LSG showed greater trunk angle than that of SG. 3) At E3 LSG revealed higher angular velocities than that of SG. 4) No significant differences was found for AP GRF between groups but LSG showed greater VGRF than that of SG. Keyword : 110m Hurdle, Hurdling, Kinetic and Kinematic

The purpose of this study was to investigate the balance differences between skilled players and less-skilled players during Hakdariseogi motion of Keumgang Poomsae in Taekwondo. To achieve the study goal, total of 10 Taekwondo athletes; 5 skilled players(S, body mass: 67.0±5.7 kg, height: 174.0±4.8 cm, age: 20.0±2.0 yrs) and 5 less-skilled players (LS, body mass: 73.0±4.9 kg, height: 176.4±6.1 cm, age: 20.8±1.3 yrs) participated in this study, A three-dimensional motion analysis with 8 infrared cameras and one force plate whose sampling frequency as 30 Hz and 300 Hz, respectively, were performed, Participants` motion were divided into three phases which were preparation phase (P1), performing phase (P2) and maintaining phase (P3). The range and velocities of COP, the range and RMS of ground reaction torque and displacement between COM and center of BOS of each phase were computed. In this study, at P1 and P3 which were double and single stance, respectively, the range and M-L velocities of COP revealed significantly higher in LS compared with those of S(p

The purpose of this study was to provide scientific information to track and field coaches and athletes through the analyses of the biomechanics characteristics of the top 4 sprinters in the men`s 100 m final in the IAAF World Championships Daegu 2011. Twelve video cameras (Sony, Japan) were used to capture the mid portion of the race (40 m - 70 m) with a sampling frequency of 60Hz. Biomechanical variables including the right ankle, knee and hip angles, the trunk angle, and the velocity of center of mass (COM) in the running direction, were calculated with the Kwon 3D program (Visol, Korea). Correlation coefficients between the COM velocity and each variables were calculated using Matlab 2008a (MathWorks, USA) at an alpha level of 0.05. The findings indicated that Yohan Blake (JAM) showed greater range of motion at the ankle and hip. Walter Dix(USA) showed greater knee and trunk movement, and Kim Collins (SKN) showed more dorsi-flexed and extended trunk angles during the race. Finally, Christophe Lemaitre (FRA) showed more plantar-flexed ankle with a less trunk motion, throughout the analyzed race.

The purpose of this study was to analyze the kinematic characteristics of the finalists in the women`s 100 m event to provide important information to coaches and athletes. Three different biomechanics techniques were applied for analyzing sprinter motion: LAVEG, a panning technique, and 12 video cameras for 3 dimensional analysis of the 40 m - 70 m portion of the race. Carmelita Jeter(USA) performed the maximum speed of 10.54 m/s at the distance of 58.2 m. There was a tendency to show a better performance time with a high number of steps (p

The purpose of this study was to investigate the kinematic characteristics of the and hurdle clearances during the final of the 100-m hurdles event at the IAAF World Championships, Daegu 2011. To this end, the hurdling motions of the top 4 ranked female hurdlers in the competition were analyzed. A total of 12 cameras were used to record their motions, with a sampling frequency of 120 Hz. The cameras were calibrated using control objects that covered all of the lanes ( lanes). After analyzing all the data, we arrived at the following results. For the take-off phase, a negative relationship between the take-off time (CT) and athlete`s rank was found. In addition, the average distances from the hurdle to take-off (L1) were shown to be 2.23 m and 2.17 m for the and hurdles, respectively. For the distance from the hurdle to landing (L2), Pearson ( rank) and Carruthers( rank) showed inconsistent patterns whereas Harper ( rank) and Porter ( rank) showed consistent patterns. All althetes revealed similar 3 steps patterns between hurdles, which consisted of a shorter step, longer step and shorter step.

The purpose of this study was to evaluate the kinematic characteristics of and hurdle clearances during the final of the 110-m hurdles at the IAAF World Championships, Daegu 2011. To this end, the hurdling motions of the top 4 ranked male hurdlers in the competition were analyzed. A total of 12 cameras were used to record their motions, with a sampling frequency of 120 Hz. The cameras were calibrated using control objects that covered all of the lanes (1st~8th lanes). After analyzing all the data, we arrived at the following results. In the take-off phase, all athletes revealed similar take-off times (CT), and similar distances from the take-off to hurdleto (L1) and hurdle to landing (L2). In particular, Turner, ranked , had an inconsistent L2 and may need further training to correct it. In the flight phase, Richardson, ranked , showed the longest flight distance, whereas Xiang, who was ranked , showed the highest CG height from the hurdle. For the step patterns, to increase the pitch frequency, Richardson and Xiang used shorter 3-step lengths than Turner and Oliver.

Human body is hard to be in perfect balance during walking. Most of time the trunk is supported by one leg and the center of mass(COM) falls to the contralateral side. Thus, dynamic variables such as the velocity of the COM should be considered when gait stability is evaluated. The purpose of this study was to investigate whether the extrapolated center of mass(XCom) which utilized the COM position and its velocity, is appropriate to evaluate gait stability. Ten healthy adults participated in this study and performed 3 different types of gaits(normal(NG), hands on waists(HWG), and hands on shoulders(HSG)) onto 4 different types of obstacle(obstacle height: 0%, 30%, 40% and 50% of leg length). Medio-lateral Com-CoP and XCom-CoP inclination angle were calculated during support phase. For all condition, greater M-L XCoM-CoP inclination angles were found(p

The purpose of this study is to investigate the effect of a 12-week aquatic exercise on obstacle gait in older women. Originally, 20 healthy female elderly participated this study but 12 of them completed the program. All participants were trained in the aquatic exercise program by an authorized trainer. They had come to the authors' lab three times during training period(0, 6, 12 weeks) and performed obstacle gait with three different height(0, 30, and 50% of leg length). After performed 3-Dimensional motion analysis following results were found. (1) For the CV, MVHC, TC, HC, statistically significances were shown in obstacle height. Although significant training effects were not shown, all variables showed typical patterns and it was considered as efficient motion to overcome the height obstacles. (2) The anterior-posterior and vertical GRF of support leg during support phase were revealed in height effect but in training one. However, differences between Peak 1 and Peak 2 in vertical GRF increased as training period increased. (3) Knee and hip resultant joint moments were affected by training but ankle resultant moments remained unchanged.

Background Tibial stress fracture (TSF) is a common injury in basketball players. This condition has been associated with high tibial shock and impact loading, which can be affected by running speed, footwear condition, and footstrike pattern. However, these relationships were established in runners but not in basketball players, with very little research done on impact loading and speed. Hence, this study compared tibial shock, impact loading, and foot strike pattern in basketball players running at different speeds with different shoe cushioning properties/performances. Methods Eighteen male collegiate basketball players performed straight running trials with different shoe cushioning (regular-, better-, and best-cushioning) and running speed conditions (3.0 m/s vs. 6.0 m/s) on a flat instrumented runway. Tri-axial accelerometer, force plate and motion capture system were used to determine tibial accelerations, vertical ground reaction forces and footstrike patterns in each condition, respectively. Comfort perception was indicated on a 150 mm Visual Analogue Scale. A 2 (speed) × 3 (footwear) repeated measures ANOVA was used to examine the main effects of shoe cushioning and running speeds. Results Greater tibial shock (P < 0.001; η2 = 0.80) and impact loading (P < 0.001; η2 = 0.73–0.87) were experienced at faster running speeds. Interestingly, shoes with regular-cushioning or best-cushioning resulted in greater tibial shock (P = 0.03; η2 = 0.39) and impact loading (P = 0.03; η2 = 0.38–0.68) than shoes with better-cushioning. Basketball players continued using a rearfoot strike during running, regardless of running speed and footwear cushioning conditions (P > 0.14; η2 = 0.13). Discussion There may be an optimal band of shoe cushioning for better protection against TSF. These findings may provide insights to formulate rehabilitation protocols for basketball players who are recovering from TSF.

S. H. YOON, The Effect of Stair Depth on Ground Reaction Force Parameters - Asymmetric and Variability Indices -. Korean Journal of Sport Biomechanics, Vo l. 18, No. 1, pp. 169-178, 2008. The goals of this study were to provide data of 3 dimensional ground reaction force(GRF) parameters during stair ascent and descent on three different stair runs and to investigate variability and asymmetry index of them. 10 healthy adults participated in this study and performed 7 different typ es of gait with 10 trials each. After data analysis, following results were found. Firstly, stair run did not affect on the pattern of GRF parameters, coefficient of variation and asymmetry index. Secondly, a significant differen t GRF pattern was found between level walking and stair walking. Especially, ascending stair walking has only large Fz1 and small Fz3 while level walking and descending stair walking have a "M" shape connected by Fz1, Fz2 and Fz3. Thirdly, only vertical GRF parameters of stair walking revealed acceptable coefficient of variation and asymmetry index. KEYWORDS : STAIR RUN, ASCENDING, DESCENDING, VARIABILITY, ASYMM ETRY INDEX, WALKING

[Purpose] The purpose of this study was to investigate the effects of an 8-week program of Pilates exercise on gait in chronic hemiplegia patients and to determine whether or not it can be used for rehabilitation in postsrtoke patients. [Subjects and Methods] Twenty individuals with unilateral chronic hemiparetic stroke (age, 66.1 ± 4.4 yrs; height, 162.3 ± 8.3 cm; weight, 67.4 ± 12.3 kg) participated in this study and were randomly allocated equally to either a Pilates exercise group or a control group. To identify the effects of Pilates exercise, a 3-D motion analysis with 8 infrared cameras was performed. [Results] For the gait parameters, improvements were found in the Pilates exercise group for all variables, and statistical significance was observed for stride length, gait velocity, knee range of motion and hip range of motion. For the asymmetry indexes, insignificant improvements were found for all variables in the Pilates exercise group. [Conclusion] In conclusion, an 8-week program of Pilates exercise had a positive influence on improving the gait ability of poststroke patients, and the intervention could be applied to poststroke patients with various levels of physical disability by adjusting the intensity of training.

The gait instability in the elderly has been associated with age-related deterioration in physical strength and reducing the potential for elderly falls requires regular exercise. In 2005, National Center for Injury Prevention and Control(NCIPC) reported that most elderly falls occur during activities in daily living(ADL). To better reveal biomechanic mechanisms underlying age-related degeneration in gait stability, and to enhance the assessment of falls risk, an accurate quantification of a person`s balance maintenance during locomotion is needed. Instantaneous orientation of the line connecting COP and COM can characterize whole body position with respect to the supporting foot during gait and the angle between this line and the vertical line passing through the COP known as a good assessment to detect the elderly gait instability. Therefore the purpose of this study was to investigate a 6-month walking exercise effects in reducing elderly fall risk factors by using COP-COM inclination angles. Twenty-two community-dwelling elderly participated this study. The participants performed a walking exercise(3 times/week, 1 hour/visit) for 6 months. Laboratory kinematics during walking was assessed at months 0, 3 and 6. Significant increased in gait velocity was found among periods(p

S. H. YOON, Biomechanical Analysis of the Elderly Gait with Wal king Assistive Devices. Korean Journal of Sport Biomechanics, Vol. 17, No. 2, pp. 1-9, 2007. Walking is not only an essential component of the human mobility, but also is a good exercise. Inability to walk freely can reduce an individual’s quality of life and independence substantially. Being a relatively low impact activ ity, walking is particularly good for the elderly and research has shown that regular walking in the elderly reduces the chance of fall-related injuries and mental diseases as well. In spite of the documented benefits of regula r walking, it is still difficult to walk without the aid of assistive devices for the frail elderly who have lower extremity problems. Assistive walking devices (AWD), such as crutches, canes, hiking-poles, T-Poles and walke rs, are often prescribed to the elderly to make their walking be safe and efficient. Many researchers have demo nstrated the effects of AWDs such as reducing lower extremity loading, improved dynamic/gait stability, yet, no study has been done for gait pattern when the elderly gait with AWDs. Therefore, the purpose of this study was to examine whether T-Poles, one of the AWDs, change the elderly gait pattern. Eight community-dwelling female elderly participated in this study. Laboratory kinematics during walking with T-Poles(PW) and with out T-Poles(NPW) was assessed. PW showed significant increase in step width, stride length, gait velocit y and decrease in swing time. No significances were found in lower body joint angles but meaningful trend and pattern were found. Maybe the reason was due to the participants. Our participants were healthy enough so that the effect of T-Poles was minimum. PW also showed typical gait phases which are no single support phase during a gait cycle. It indicates that walking with T-Poles may guarantee safe and confident walking to the frail e lderly. KEYWORDS : T-POLES, GAIT, ELDERLY, LOWER BODY, ELDERLY FALLS

Human dynamic models have been used to estimate joint kinetics during various activities. Kinetics estimation is in demand in sports and clinical applications where data on external forces, such as the ground reaction force (GRF), are not available. The purpose of this study was to estimate the GRF during gait by utilizing distance- and velocity-dependent force models between the foot and ground in an inverse-dynamics-based optimization. Ten males were tested as they walked at four different speeds on a force plate-embedded treadmill system. The full-GRF model whose foot-ground reaction elements were dynamically adjusted according to vertical displacement and anterior-posterior speed between the foot and ground was implemented in a full-body skeletal model. The model estimated the vertical and shear forces of the GRF from body kinematics. The shear-GRF model with dynamically adjustable shear reaction elements according to the input vertical force was also implemented in the foot of a full-body skeletal model. Shear forces of the GRF were estimated from body kinematics, vertical GRF, and center of pressure. The estimated full GRF had the lowest root mean square (RMS) errors at the slow walking speed (1.0m/s) with 4.2, 1.3, and 5.7% BW for anterior-posterior, medial-lateral, and vertical forces, respectively. The estimated shear forces were not significantly different between the full-GRF and shear-GRF models, but the RMS errors of the estimated knee joint kinetics were significantly lower for the shear-GRF model. Providing COP and vertical GRF with sensors, such as an insole-type pressure mat, can help estimate shear forces of the GRF and increase accuracy for estimation of joint kinetics.

[Purpose] The purpose of this study was to investigate the effect of 8 weeks aquatic exercise on the gait stability of the elderly using dynamic factors: center of mass (COM), velocity of center of mass (COMV), and center of pressure (COP). [Subjects] Eleven elderly participants (age: 77.18 ± 4.96 yrs, height: 149.48 ± 3.61 cm, body mass: 56.94 ± 6.62 kg, and leg length: 82.36 ± 2.98 cm), participated in this study. [Methods] To identify the 8-week aquatic training effect, 3-D motion analysis with 7 infrared cameras and one force plate, was performed. [Results] For the COM-COP inclination angles, significantly decreased medial inclination angles were shown in both the posterior and anterior swing phases. For the COMV-COP inclination angles, decreased medial inclination angles were shown in both the posterior and anterior swing phases, but significant difference was found only in the posterior phase. [Conclusion] The results suggest that 8 weeks aquatic exercise is effective at improving the gait stability of the elderly. Further studies should extend the training period to gain statistically significant results for the effect of aquatic exercise in the anterior-posterior direction.

Stroke is the leading cause of long term adult disability in United States and impaired walking function is a common neurological deficit following stroke. Even after extensive inpatient and outpatient therapy only 60% of stroke survivors are able to walk independently. Furthermore, many continue to

The use of digital camcorders in biomechanical analyses can introduce errors due to inter-camera time offsets. The faster the motion being recorded the greater the error. A sequential synchronization method was developed in this study to achieve sub-field camera synchronization for multiple camcorders through numerical optimization. A recreational golfer performed ten drives while being recorded with four digital camcorders (60-Hz sampling rate). Video signals were sampled at 10,000 Hz to determine the actual inter-camera time offsets. The optimized inter-camera time offsets were computed based on three markers placed on the shaft, each separated by 200 mm. The inter-camera time offset error was computed as the difference between the optimized and actual inter-camera time offsets. The inter-camera time offset error reduced on average from 0.518 to 0.019 fields (1 field = 16.7 ms) or less due to sequential optimization. The optimized global reconstruction errors were less than 19% of the unadjusted values. It was concluded that the ability to synchronize multiple (two or more) cameras using a sequential sub-field optimization strategy promises to extend the use of relatively inexpensive digital camcorders to motions considered too fast for the low field rates of such cameras. The sequential approach presented provides a balance between computation time and reconstruction accuracy.