• Physical Therapy Rehabilitation Science
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• v.9 no.1
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• pp.36-42
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• 2020

Objective: Many caregivers often carry infants using baby carriers until they are approximately 36 months old. The purpose of this study was to compare the muscular activity of the trunk and lower leg muscles during trunk flexion-extension movements in correspondence to various wearing methods of a baby carrier blanket. Design: Cross-sectional study. Methods: Sixteen healthy adult women were to wear baby carrier blankets in five different ways in terms of direction and height, followed by flexion-extension of the trunk. Erector spinae (ES), rectus abdominis, rectus femoris (RF), biceps femoris (BF) muscle activities and triaxial acceleration of trunk were investigated. Results: The front-wearing method of the baby carrier blanket increased the muscular activity of the ES muscle, and wearing the baby carrier blanket at waist height in the same direction was significantly higher than wearing it at pelvic height (p<0.05). As the angle of flexion increased during trunk flexion-extension, the muscle activity of the ES, BF, and the RF increased. There was a greater increase in muscle activity of the ES and the BF during extension compared to flexion (p<0.05). Conclusions: If it is difficult to wear a baby carrier blanket due to lumbar pain, it is recommended to lower the wearing height of the baby carrier to the pelvic level so that the external load can be transferred to the lower extremity. In addition, it appears to be necessary to hold the baby and distribute the load onto the waist through proper body control when performing flexion-extension movements of the trunk. More objective and scientific research that includes various daily tasks and evaluation methods are needed.

• Korean Journal of Applied Biomechanics
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• v.17 no.3
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• pp.133-145
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• 2007

The purpose of this paper was to compare of difference between energy walking and normal walking. Subjects were selected 8 male undergraduates. The kinematic variables of a pelvis and a thorax were analysed at the take off and contact with 3d cinematography. In addition to the variables, the phase plot angle was calculated in order to definite characteristics in the phase space. The pelvic angle and angular velocity showed significant differences in the flexion/extension between two walking patterns. The pelvic angle and angular velocity were increasing when walking speed was increasing and magnitude of the variables of energy walking was larger than corresponding values for normal walking. On the other hand, the thoracic angle demonstrated significant differences in the flexion/extension and rotation between two walking patterns. The angles of energy walking were smaller in the flexion/extension and were larger in the rotation than the angle of normal walking. The kinematic characteristics of energy walking were also showed clearly significant differences in the range of motion and the relative angle of the trunk. The angle of phase plot only showed demonstrated a significant difference in the rotation at contact between the two walking patterns.

• Physical Therapy Korea
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• v.10 no.1
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• pp.63-76
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• 2003

This research was performed to compare spinal segment motion angle between low back pain (LBP) group and painless group during trunk flexion-extension and to investigate the effect of transversus abdominis strengthening exercise on spinal segment motion angle in LBP group. Nine subjects with LBP and ten subjects without LBP participated. Transversus abdominis strengthening exercise was performed in LBP group for three weeks, and spinal segment motion angles were compared before and after the exercise performance. Spinal segment motion angles were measured both in sitting and standing position. Results were as followed: 1) Subjects' average age was 24.79 years, height was 167.84 cm, and weight was 59.95 kg. 2) Spinal segment motion angle of T10/l1 was significantly higher in LBP group compared with painless group (p<.05) in sitting position during trunk flexion-extension. 3) In sitting position, whereas entire lumbar segment motion angles were lower in LBP group compared with painless group (p<.05), angle of L4/5 was higher in LBP group compared with painless group (p<.05). 4) There was no significant difference in thoracic segment motion angle in standing position. 5) After three weeks of transversus abdominis strengthening exercise, thoracic segment motion angle increased both in sitting and standing position (p<.05). 6) In painless group, there was no significant difference in entire spinal segment motion angles in sitting and standing position (p>.05). When spinal segment motion angles were compared between sitting and standing position, there were slight differences. In sitting position, there was no difference in spinal segment motion angle between LBP group and painless group while hip joint motion angle and sacral inclination angle of LBP group was lower than those of painless group (p<.05). In standing position, lumbar segment motion angle was significantly lower in LBP group than that of painless group. Transversus abdominis strengthening exercise influenced thoracic segment motion angle more significantly than lumbar segment motion angle.

• PNF and Movement
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• v.13 no.2
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• pp.81-88
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• 2015

Purpose: The purpose of this study was to analyze the effect of normal timing according to angular motion in PNF patterns on electromyography (EMG) activity in rectus abdominis, internal oblique abdominal muscle, external oblique abdominal muscle, and erector spinae. Methods: Ten healthy adults volunteered to participate in this study. The participants were required to complete following two PNF extremity patterns; upper extremity extension- adduction-internal rotation pattern with $180^{\circ}$, $90^{\circ}$, $30^{\circ}$ and lower extremity flexion- adduction-external rotation pattern with $0^{\circ}$, $60^{\circ}$, $90^{\circ}$. A paired t-test was used to determine the influence of the two PNF patterns on muscle activity in each muscle. Descriptive statistics were used to determine the ratio of local muscle activity to global muscle activity. Results: In terms of their effect on applied normal timing, the upper and lower extremity pattern significantly affected the rectus abdominis, internal oblique, external oblique, and erector spinae (p < .05). The upper extremity pattern (at an extension angle of $30^{\circ}$) and the lower extremity pattern ((at a flexion angle of $90^{\circ}$) influenced the rectus abdominis, internal oblique, external oblique, and erector spinae (p < .05). Conclusion: The effect of the upper and lower extremity patterns on applied normal timing was significant in that these patterns increased trunk muscle activation. The upper extremity pattern (at an extension angle of $30^{\circ}$) and the lower extremity pattern (at a flexion angle of $90^{\circ}$) increased trunk muscle activation. Normal timing is required to increase trunk muscle strength and extremity movement.

• Korean Journal of Applied Biomechanics
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• v.22 no.1
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• pp.83-94
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• 2012

The purpose of this study was to analyse the effect of posture correction & stabilization according to horse rider's(n=10) skill levels of novice(0wk), mid-skill(12wk) & skill(24wk) in walk & trot. First, Mean posture of 3 times experiments; Anterior & posterior leaning posture of trunk showed rather unstable according to progress of the stages of TD1, TO, TD2 phase, and also shoulder & elbow angle, which effects to the distance from bit to rein, showed unstable riding posture. There was close relationship between shoulder and elbow Angle in walk and hip, knee & ankle angle in trot. Second, Posture correction & stabilization according to riding skill levels; Anterior & posterior leaning posture of trunk did not show significant difference statistically but showed approaching tendency to trunk's vertical line and showed significant difference(p<.05) according to improvement of skill levels in walk & trot horse riding. Hip angle showed significant difference according to progress of the stages of TD1, TO, TD2 phase(p<.05) and showed tendency maintaining the larger thigh flexion according to improvement of skill levels in walk & trot. Knee angle showed more stable posture by maintaining the larger flexion between thigh and shank according to improvement of skill levels in walk & trot(p<.05). Ankle angle also showed tendency maintaining the larger plantar flexion of foot according to improvement of skill levels in walk & trot. When considering the above, regular horse riding program could be useful in posture correction & stabilization according to improvement of skill levels of novice(0wk), mid-skill(12wk) & skill(24wk) in walk & trot.

• Physical Therapy Korea
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• v.14 no.1
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• pp.21-27
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• 2007

The purpose of this study was to evaluate isometric trunk extension strength in hemiplegic patients, and to compare that with normal subjects to find a correlation between trunk extension strength and the functional independent degree in hemiplegic patients. Fifteen hemiplegic male patients (mean age $55.2{\pm}10.2$ years) and twenty-five healthy male subjects (mean age $54.6{\pm}10.3$ years) completed isometric trunk extension. Strength was measured at 0, 12, 24, 36, 48, 60, and 72 degrees of trunk flexion. The functional independent degree was assessed by Functional Independence Measure (FIM). Mean isometric trunk extension strength was 91.2 ft-lbs, 120.7 ft-lbs, 142.3 ft-lbs, 156.4 ft-lbs, 173.5 ft-lbs, 184.1 ft-lbs, and 195.3 ft-lbs in the hemiplegic patients group, and 135.6 ft-lbs, 175.6 ft-lbs, 204.4 ft-lbs, 221.9 ft-lbs, 231.2 ft-lbs, 246.8 ft-lbs, and 259.7 ft-lbs in the normal subjects group. The values of isometric trunk extension strength had a descending linear correlation pattern from trunk flexion angle to extension angle. Trunk extension strength in hemiplegic patients was significantly lower than that of normal subjects (p<.05) but did not correlate with the FIM total score (p>.05). Therefore, the isometric trunk extension strength in hemiplegic patients was lower than that of normal subjects and did not correlate with the functional independent degree.

• Korean Journal of Applied Biomechanics
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• v.17 no.2
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• pp.61-73
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• 2007

The purpose of this study was to investigate the influence of the muscular endurance on the kinematic factors during a prolonged run. Subjects, 12 males, who were divided into three groups(lower group, general group, and in higher group) after measuring the lower limb's muscular endurance previously. They were asked toe run on the treadmill at 7.4km/h of speed. To analyze the kinematics parameters of the trunk during running, the ProReflex MCU Camera(Qualisys, Sweden) were used. All parameters were sampled from 5 minute, 40 minute, and 60 minute moments during running. An ANOVA with Repeated Measure was used to test the statistic significance between and within groups for all parameters determined with SPSS 11.0. Significance was defined as p<.05. The conclusions were as follows; There was significantly difference within(lapse of running time) groups in the take-off and minimum knee angle event of swing phase of the trunk flexion and extension. In conclusion, the muscular endurance affected on movement of the trunk during a prolonged run. In addition, it showed that there was significant difference in the energy consumption by lapse of running time. Therefore, it seems to be relationships between the muscular endurance and running efficiency.

• Physical Therapy Korea
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• v.24 no.4
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• pp.1-10
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• 2017

Background: Flexion-relaxation phenomenon (FRP) was a term which refers to a sudden onset of myoelectric silence in the erector spinae muscles of the back during standing full forward flexion. Hamstring muscle length may be related to specific pelvic and trunk movements. Many studies have been done on the FRP of the erector spinae muscles. However, no studies have yet investigated the influence of hamstring muscle flexibility on the FRP of the hamstring muscle and lumbopelvic kinematics during forward bending. Objects: The purpose of this study was to examine the flexion-relaxation ratio (FRR) of the hamstring muscles and lumbopelvic kinematics and compare them during forward bending in subjects with different hamstring muscle flexibility. Methods: The subjects of two different groups were recruited using the active knee extension test. Group 1-consisted of 13 subjects who had a popliteal angle under $30^{\circ}$; Group 2-consisted of 13 subjects who had a popliteal angel above $50^{\circ}$. The kinematic parameters during the trunk bending task were recorded using a motion analysis system and the FRRs of the hamstring muscles were calculated. Differences between the groups were identified with an independent t-test. Results: The subjects with greater hamstring length had significantly less lumbar spine flexion movement and more pelvic flexion movement. The subjects with greater pelvic flexion movement had a higher rate of flexion relaxation during full trunk bending (p<.05). Conclusion: The results of this study suggest that differences in hamstring muscle flexibility might cause changes in people's hamstring muscle activity and lumbopelvic kinematics.

• Korean Journal of Applied Biomechanics
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• v.15 no.4
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• pp.13-24
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• 2005

The purpose of this study was to compare kinematic data between experts and novices, and identify difference kinematic parameters changing direction to kick in penalty kick of soccer play. Novice subjects were 5 high school students Who has never been experienced a soccer player, and expert subjects were 5 competitive high school soccer players. The 3-d angle was calculated by Euler's Angle by inertial axis and local axis with three-dimensional cinematography. Kinematic parameters in this study consisted of angles of knee joints, hip joints, lower trunk and upper trunk when the support foot was contacted on ground and kicking foot impacted the ball. The difference of angle of knee joints in the flexion/extension was insignificantly showed below $4{\sim}9^{\circ}$ in groups and directions of ball at the time of support and impact. But the difference of angle of hip joint was significant in groups and directions of ball at the time of support and impact. Specially the right hip joint of experts were more flexed about $12^{\circ}$($43.99{\pm}6.17^{\circ}$ at left side, $31.87{\pm}4.49^{\circ}$ at right side), less abducted about $10^{\circ}$ ($-31.27{\pm}4.49^{\circ}$ at left side, $-41.97{\pm}6.67^{\circ}$ at right side) at impact when they kicked a ball to the left side of goalpost. The difference of amplitude angle in the trunk was significantly shown at upper trunk not lower trunk. The upper trunk was external rotated about $30^{\circ}$ (novice' angle was $-16.3{\pm}17.08^{\circ}$, expert's angle was $-43.73{\pm}12.79^{\circ}$) at impact. Therefore the significant difference of kinematic characteristics could be found at the right hip joint and the upper trunk at penalty kick depending on the direction of kicking.

• Journal of the Korean Society of Physical Medicine
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• v.5 no.3
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• pp.405-412
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• 2010

Purpose : The purpose of this study was to assess the effects of the trunk muscle activity on bridging exercise according to the knee joint angle. Methods : Twenty-five healthy adults volunteered to participate in this study. Subjects were required to complete following four bridging exercises; knee joint flexion $120^{\circ}$, $90^{\circ}$, $60^{\circ}$, $45^{\circ}$. Surface electromyography from selected trunk muscles was normalized to maximum voluntary isometric contraction. Muscle activity was measured by QEMG-4 system(LXM 3204, Laxtha Korea). A repeated measures of one-way ANOVA with post-hoc Bonferroni's correction was used to determine the influence of bridging exercise on muscle activity for each muscle and descriptive statistics was used to determine local/global muscle ratio. Results : The internal oblique of bridging exercises $120^{\circ}$, $90^{\circ}$ showed significantly(p<.05). The erctor spinae of all bridging exercises showed significant excepted between $60^{\circ}$ and $45^{\circ}$(p<.05). Median of internal oblique/rectus abdominis ratio of $120^{\circ}$ was 4.41, $90^{\circ}$ was 3.94, $60^{\circ}$ was 3.58, $45^{\circ}$ was 3.39. Median of internal oblique/external oblique ratio of $120^{\circ}$ was 2.66, $90^{\circ}$ was 2.43, $60^{\circ}$ was 2.87, $45^{\circ}$ was 2.64. Conclusion : Angular motion decreasing with knee joint flexion made erector spinae activation increase. on the other hand, as decreasing abdomen muscle activation, the more performing motor learning is required for abdomen muscle strength and co-contraction for the trunk stabilization.