The purpose of this research was to analyze the effects of the increase of the femoral anteversion angle on the unbalanced quadriceps femoris muscle causing the increase of the valgus force on the knee joints and patellofemoral pain syndrome by comparing with the group that shows the smaller femoral anteversion angle. The method for the research was to compare the femoral muscle's activity while the subjects were maintaining the knee joint flexed isometrically for 10 seconds. The evaluation tool for femoral muscle's activity was QEMG-4 (model LXM 3204). The results were as followings. Firstly, in case of the experimental group, the muscle strength of the vastus lateralis muscle was strong while the rectus femoris and vastus medialis were weak. In these facts, we can see the statistically meaningful difference in vastus medialis muscle activity. Secondly, in the muscle activity analysis for vastus lateralis and medialis of the two groups, we could see the vastus lateralis muscle was strong in anteversion wider for experimental group while the vastus medialis muscle contracted far more stronger in anteversion smaller for control group. From these results, we can see the significant differences in muscle recruitment between the two groups. Above results show that if the anteversion becomes wider, vastus medialis muscle will become seriously weaker, on the other hand, vastus lateralis act stronger.
This study examined the ability of human subjects to match a force in their quadriceps muscle during fatigue. Twenty subjects (mean age: 23.4 yrs, mean height: 167.8 cm, mean weight, 62.6 kg) were enrolled in the experiment. In the force-matching task, the quadriceps muscle generated 50% of the MVIC (maximum voluntary isometric contraction) torque under visual control and then without visual feedback. After inducing fatigue in the quadriceps muscle, the subjects were required to match 50% of the MVIC torque without visual feedback. The perceived magnitude of the force and force-matching errors were measured. 50% of the MVIC torque was perceived from 39.96 Nm in the pre-fatigue condition to 44.95 Nm in the post-fatigue condition. 50% of the MVIC torque-matching errors increased significantly from .55% in the pre-fatigue condition to 9.6% in the post-fatigue condition (p<.001). in addition, there were significantly more force-matching errors in women than in men (p<.01). In conclusion muscle fatigue can interfere with a subject's ability to match a force. This suggests that muscle fatigue may contributes to the sensitization of the proprioception.
Falling is a serious problem associated with aging. Unintentional injury, which most often results from falling, is one of the leading causes of death in elderly people. The purpose of this study is to investigate the risk factors of falls and to compare characteristics of people who fall with that of non-fallers among the rural community-dwelling elderly of Korea. A sample of 201 people, living in the community, aged 60 years and over was taken from the members of a center for seniors located in Jecheon city. The mean age of the participants was 70.5 years of age. The participants are comprised of 151 women and 50 men. Eighty four of the 201 participants (41.8%) fell during the previous year. Twenty two of the fallers (26.2%) fell down more than two times. It was found that fallers had poorer eyesight, multiple chronic diseases and a more difficult time walking than non-fallers. In the logistic regression analysis of falls, only the difficulty of walking one kilometer (OR=2.4) and chronic diseases (OR=2.5) have shown an increased risk of falls. The risk of recurrent falls is, in addition, influenced by the difficulty of walking one kilometer. The result of our study shows that the impairment of mobility was the strongest risk factor of recurrent falling.
The purpose of the present study was to examine gaze effects on spatial and kinematic characteristics during a pointing task. Subjects were asked to watch and point to an aimed target (2 mm in diameter) displayed on a vertically mounted board. Four gaze conditions were developed as combinations of "seeing-aiming" in terms of the eye movements: Focal-Focal (F-F), Focal-Fixing (F-X), Fixing-Focal (X-F), and Fixing-Fixing (X-X). Both the home target and an aimed target were presented for 1 second and then were disappeared in F-F and X-F. In X-F and X-X, only an aimed target disappeared after 1 second. Subjects were asked to point (with index finger tip) to an aimed target accurately as soon as the aimed target was removed. A significant main effect of gaze was found (p<.01) for normalized movement time. Peripheral retina targets had significantly larger absolute error compared to central retina targets on the x (medio-lateral) and z (superior-inferior) axes (p<.01). A significant undershooting to peripheral retina targets on the x axis was found (p<.01). F-F and X-F had larger peak velocities compared to F-X and X-X (p<.01). F-F and X-F were characterized by more time spent in the deceleration phase compared to F-X and X-X (p<.01). The present study demonstrates that central vision utilizes a form of on-line visual processing to reach to an object, and thus increases spatial accuracy. However, peripheral vision utilizes a relatively off-line visual processing with a dependency on proprioceptive information.
This study was to investigate the influence of cooling on muscle force and viscoelastic properties of tendon structures in themedial gastrocnemius (MG) muscle. The subject was instructed to gradually increase force (10% MVC step) from a relaxed state to MVC within 3 s. At this time, it was measured by an ultrasonographic probe was attached and that an electrode was attached to monitor EMG. The F values at 50 100% of MVC were significantly greater under the cold condition than under the non-cold condition (p<.05). The values at 80~100% of MVC were significantly higher under the cold condition than under the non-cold condition (p<.05). The elongation under the non-cold condition had a tendency to be greater than that under the cold condition. The results suggest that cooling results in an increase in the stiffness of tendon structures with a reduction of muscle force and elongation.
The purpose of this study was to determine the effects of slump sitting postures on the masticatory, neck, shoulder, and trunk muscles associated with work-related musculoskeletal disorders (WRMD). Eleven healthy adults (age, 23.3±2.7 yrs; height, 174.0±4.1 ㎝; weight, 61.4±6.6 ㎏) participated in this study. The participants were free of injury history and neurologic deficits in the masticatory, neck muscles and upper extremities at the time of participation. The subjects were asked to perform erect and slump sitting postures under the guidance of physical therapists. The surface electromyography (EMG) was recorded from the anterior temporalis, masseter, upper trapezius, serratus anterior, middle trapezius, L3 paraspinal, external abdominal oblique, gluteus maximus muscles of 11 adults as they performed visual terminal display work, which are known as the weakened and tightened muscles owing to WRMD. The recorded signals were averaged and normalized to the mean amplitude of the EMG signal obtained during submaximal reference voluntary contractions. The results of study were as follows: The masseter, upper trapezius, serratus anterior, middle trapezius, L3 paraspinal, external abdominal oblique muscles significantly differed in the slump sitting posture (p<.05). The muscle activities of the serratus anterior, middle trapezius muscle, and external abdominal oblique were significantly lower and that of the masseter, upper trapezius, L3 paraspinal muscles were significantly higher. Further research is needed to assess the motor control problems and the function of the deep muscles in posture stability of patients with WRMD.
The purpose of this study was to compare the static balance of standing position between adolescent idiopathic scoliosis (AIS) and a normal group that were aged-matched. There were forty subjects included in this study. Twenty-seven healthy subjects (age, 13.9±1.2 yrs; height, 161.9±7.5 ㎝; weight, 52.2±7.7 ㎏) and thirteen AIS subjects (age, 14.2±2.2 yrs; height, 161.5±8.7 ㎝; weight, 48.1±8.1 ㎏) were participated in the study. The thirteen subjects in the AIS group had a major Cobb angle between 20.1° and 49°. Each group was tested with the Balance Performance Monitor (BPM). The parameters for static balance were sway area, sway path, max velocity, mean balance, anterior-posterior angle, and left-right angle of each group with their eyes opened and again with their eyes closed. Both sides of the forward reach test and the lateral reach test were also performed on each group. Results from the BPM tested showed significantly increases in all parameters of static balance with those patients with AIS under the conditions where eyes were opened and closed. In the right and left forward reach test, there was no significant difference between normal and AIS groups. However, in the lateral reach test with right and left direction, there were significant differences between normal and AIS groups. For the normal subjects, there were significant differences in the parameters with sway path and anterior-posterior sway angle between the eyes opened and closed. However, there were no significant differences in the all parameters between eyes opened and closed for the AIS subjects. These results suggest that, balance programs could be used in the rehabilitation setting for intervention of AIS and evaluation of AIS. Further study is needed to measure many patients with AIS and other functional balance scales for clinical application.
This study examined the effects of the abdominal drawing-in (ADI) maneuver using a pressure biofeedback on muscle recruitment pattern of erector spinae and hip extensors and anterior pelvic tilt during hip extension in the prone position. Fourteen able-bodied volunteers, who had no medical history of lower extremity or lumbar spine disease, were recruited for this study. The muscle onset time of erector spinae, gluteus maximus, and medial hamstring and angle of anterior pelvic tilt during hip extension in prone position were measured in two conditions: ADI maneuver condition and non-ADI maneuver condition. Muscle onset time was measured using a surface electromyography (EMG). Kinematic data for angle of anterior pelvic tilt were measured using a motion analysis system. The muscle onset time and angle of anterior pelvic tilt were compared using a paired t-test. The study showed that in ADI maneuver during hip extension in prone position, the muscle onset time for the erector spinae was delayed significantly by a mean of 43.20 ms (SD 43.12), and the onset time for the gluteus maximus preceded significantly by a mean of -4.83 ms (SD 14.10) compared to non-ADI maneuver condition (p<.05). The angle of anterior pelvic tilt was significantly lower in the ADI maneuver condition by a mean of 7.03 degrees (SD 2.59) compared to non-ADI maneuver condition (15.01 degrees) (p<.05). The findings of this study indicated that prone hip extension with the ADI maneuver was an effective method to recruit the gluteus maximus earlier than erector spinae and to decrease anterior pelvic tilting.
The purpose of this study was to determine whether a relationship existed between foot type and the location of plantar callus in healthy subjects. Twenty-five healthy subjects with plantar callus were recruited for this study. Foot deformities were classified according to the operational definitions as 1) a compensated forefoot varus, 2) an uncompensated forefoot varus or forefoot valgus, or 3) a compensated rearfoot varus. The location of plantar callus was divided into two regions. Fourteen of the 19 feet with compensated forefoot varus and six of the 9 feet showed plantar callus at the second, third or fourth metatarsal head. Five of the 6 feet with uncompensated forefoot varus and twenty of the 16 feet with forefoot valgus showed plantar callus at the first or fifth metatarsal head. A significant relationship was found between foot type and location of callus (p<.01). The results support the hypothesis that certain foot types are associated with characteristic patterns of pressure distribution and callus formation. We believe diabetic patients with insensitive feet and with the types of foot deformity should be fit with foot orthoses and footwears that accommodate their respective deformity in a position as near to the subtalar joint as possible with the goal of preventing plantar ulceration.
This study examined the effects of socket flexion angle in trans-tibial prosthesis on stump/socket interface pressure. Ten trans-tibial amputees voluntarily participated in this study. F-socket system was used to measure static and dynamic pressure in stump/socket interface. The pressure was measured at anterior area (proximal, middle, and distal) and posterior area (proximal, middle, and distal) in different socket flexion angles (5°, 0°, and 10°). Paired t-test was used to compare pressure differences in conventional socket flexion angle of 5° with pressures in socket flexion angles of 0° and 10° (α=.05). Mean pressure during standing in socket flexion angle of 10° decreased significantly in anterior middle area (19.7%), posterior proximal area (10.4%), and posterior distal area (16.3%) compared with socket flexion angle of 5°. Mean pressure during stance phase in socket flexion angle of 0° increased significantly in anterior proximal area (19.3%) and decreased significantly in anterior distal area (19.7%) compared with socket flexion angle of 5°. Mean pressure during stance phase in socket flexion angle of 10° decreased significantly in anterior proximal area (19.6%) and increased significantly in anterior distal area (8.2%) compared with socket flexion angle of 5°. Peak pressure during gait in socket flexion angle of 0° increased significantly in anterior proximal area (23.0%) compared with socket flexion angle of 5° and peak pressure during gait in socket flexion angle of 10° decreased significantly in anterior proximal area (22.7%) compared with socket flexion angle of 5°. Mean pressure over 80% of peak pressure (MP80+) during gait in socket flexion angle of 0° increased significantly in anterior proximal area (23.9%) and decreased significantly in anterior distal area (22.5%) compared with socket flexion angle of 5°. MP80+ during gait in socket flexion angle of 10° decreased significantly in anterior distal area (34.1%) compared with socket flexion angle of 5°. Asymmetrical pressure change patterns in socket flexion angle of 0° and 10° were revealed in anterior proximal and distal region compared with socket flexion angle of 5°. To provide comfortable and safe socket for trans-tibial amputee, socket flexion angle must be considered.
The purpose of the current experiment was to describe interlimb coordination when swing limb conditions are being manipulated by constraining step length or by adding a 5 or 10 pound weight to the swing limb distally. Subjects were asked to begin walking with the right limb to land on the primary target (normal step length) that is 10 cm in diameter. However, if, during movement, the light was illuminated, then the subject had to step on one of the secondary targets (long and short step length). These three step length conditions were repeated while wearing a 5 pound ankle weight and then when wearing a 10 pound ankle weight. Ground reaction force (GRF) data indicated that there were changes in the forces and slopes of the swing and stance Fx GRFs. Long stepping subjects had to increase the propulsive force required to increase step length. Consequently, swing and stance toe-off greatly increased in the long step length condition. Short step length subjects had to adequately adjust step length, which decreased the speed of gait initiation. Loading the swing limb decreased the force and slope of the swing limb. Swing and stance toe-off was longest for the long step length condition, but there was a small difference of temporal events between no weight and weight condition. It appears that subjects modulated GRFs and temporal events differently to achieve the peak acceleration force of the swing and stance limb in response to different tasks. The findings from the current study provide preliminary data, which can be used to further investigate how we modulate forces during voluntary movement from a quiet stance. This information may be important if we are to use this or a similar task to evaluate gait patterns of the elderly and patient populations.
The purpose of this study was to compare the quality of life (QOL) between breast cancer patients with lymphedema and without using the SF-36 (Korean version). Fifty-three consecutive, unselected patients who underwent treatment for breast cancer patients with lymphedema and 37 patients without lymphedema from August 4, 2004 to October 13, 2005 were interviewed and asked to complete the SF-36. These data were used to test the hypothesis that breast cancer patients with lymphedema experience impaired quality of life relative to their control group. The lymphedema group scored poorer than the control group on six of the eight subscales as well as the physical component summary scale of the SF-36 (p<.05). Only bodily pain didn't show statistical difference (p>.05). Breast cancer patients with lymphedema appear to experience problems in multiple quality of life domains compared with without lymphedema group. These findings demonstrate the need for interventions to improve the quality of life in breast cancer patients with lymphedema.