• Journal of The Korean Society of Integrative Medicine
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• v.7 no.1
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• pp.81-88
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• 2019

Purpose : The purpose of this study was to examine if there is any correlation between pelvic tilt angle and trunk motion and trunk extensor during trunk forward flexion and to measure trunk motion, onset time of trunk motion, and onset time of trunk extensor activation. Methods : The subjects of this study were 42 healthy adults. The subjects had no back pain due to neurological disease and no experience of back surgery. After pelvic tilt angle was measured, each trunk forward flexion was performed three times. Trunk motion and onset time of trunk motion were measured using Myomotion. Four sensors were used, with one located at the upper thoracic (below $C_7$), the lower thoracic ($T_{12}-L_1$), the sacrum ($S_1$), and at the center of the anterior femur. Onset time of trunk extensors (spinalis, longissimus, gluteus medius, gluteus maximus, biceps femoris, and gastrocnemius) activation was measured using a wireless surface EMG. The EMG amplitude was normalized by using the reference voluntary contraction (RVC). The statistical significance of the results were evaluated using Pearson's correlation test. Results : The correlation between pelvic tilt angle and lumbar motion, onset time of pelvis motion, and onset time of gluteus medius activation was statistically significant in a positive direction (p<.05). The correlation between pelvic tilt angle with pelvis motion, onset time of lumbar motion, and onset time of longissimus activation showed a statistically significant negative correlation (p<.05). Conclusion : The study results provide a significant contribution to our understanding of the lumbar load at the initial stage of trunk flexion. Therefore, it may be possible to provide basic data for evaluation and treatment, such as orthodontic treatment for alignment of the spine and back pain. In addition, it is necessary to focus on normal exercise pattern reeducation as well as pelvic correction during exercise in daily life or in industrial fields.

• Physical Therapy Korea
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• v.13 no.2
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• pp.61-69
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• 2006

The purpose of this study was to compare the electromyography (EMG) activities of the lumbar extensor muscles during motion of trunk flexion-extension and compare range of motion (ROM) with a 3-dimensional motion analysis system of the lumbar region between subjects with chronic low back pain (CLBP) and healthy subjects during the trunk flexion-extension, trunk rotation and trunk lateral flexion cycle. Thirty CLBP subjects and thirty healthy subjects were included. We measured the root mean square (RMS) value of the lumbar extensor muscles from resting, standing, lumbar flexion and return position. The RMS ratio was normalized from maximal EMG activity of the lumbar extensor muscles during trunk motion. The results of this study showed that the RMS ratio of the lumbar extensor was significantly higher in CLBP subjects than healthy subjects during all of trunk motion (p<.05). The ratio of the highest RMS value during flexion and extension was higher in CLBP subjects than in healthy subjects (p<.05). The ROM of the lumbar region was significantly lower in CLBP subjects than healthy subjects during trunk flexion-extension, trunk rotation and lateral flexion cycle. The relationship between the RMS ratio for full lumbar flexion and the ROM of lumbar flexion was not correlated significantly. CLBP subjects have both decreased ROM of the lumbar region and higher muscle activities of the lumbar extensor muscle than healthy subjects.

• The Journal of Korean Physical Therapy
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• v.27 no.2
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• pp.89-95
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• 2015

Purpose: The purpose of this study is to determine the effects of visual information on movement time and each angular velocity of trunk and lower extremity joints while healthy adults are in sitting and squat motion. Methods: Participants consisted of 20 healthy male and female adults; movement time and each angular velocity of trunk, pelvis, hip, knee and ankle of sitting and squat motion according to common vision, visual task and visual block were analyzed using a three dimensional motion analysis system. Results: Each angular velocity of the trunk, pelvis, hip, knee and ankle in phase 2 of the sitting showed significant difference according to the types of visual information (p<0.05). Movement time and each angular velocity of pelvis and hip in phase 2 of squat motion showed significant difference according to the types of visual information (p<0.05). According to the common vision, each angular velocity of knee and ankle in phase 1 was significantly fast in sitting (p<0.05). According to the common vision, each angular velocity of trunk, pelvis, hip, knee, and ankle in phase 2 was significantly fast in sitting (p<0.05). Conclusion: Visual information affects the angular velocity of the motion in a simple action such as sitting, and that in more complicated squat motion affects both the angular velocity and the movement time. In addition, according to the common vision, visual task and visual block, as angular velocities of all joints were faster in sitting than squat motion.

• Journal of Korean Physical Therapy Science
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• v.6 no.1
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• pp.923-929
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• 1999

The purpose of this study was to identify that the effect of the Lumbar extensor strengthening exercise on the trunk range of motion(Lumbar extensor strengthening exercise group = 15, Control group = 15). To find out the improvement of trunk range of motion, each group was examined with Modified Modified Sch ber(MMS) measurement before and after the treatments. The result are as followed. 1. After the training period, the trunk range of motion were increased in both groups. 2. After the training period, both groups revealed no sinigificant difference on the trunk range of motion.

• Korean Journal of Applied Biomechanics
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• v.19 no.1
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• pp.27-36
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• 2009

The purpose of this study was to identify effects of restricted trunk motion on the performances of the maximum vertical jump. Ten healthy males performed normal countermovement jump(NJ) and control type of countermovement jump(CJ), in which subjects were required to restrict trunk motion as much as possible. The results showed 10% decreases of jumping height in CJ compared with NJ, which is primarily due to vertical velocity at take off. NJ with trunk motion produced significantly higher GRF than RJ, especially at the early part of propulsive phase, which resulted from increased moments on hip joint. And these were considered the main factors of performance enhancement in NJ. There were no significant differences in the mechanical outputs on knee and ankle joint between NJ and RJ. With trunk motion restricted, knee joint alternatively played a main role for propulsion, which is contrary on the normal jump that hip joint was highest contributor. And restricted trunk motion resulted in the changes of coordination pattern, knee-hip extension timing compared with normal proximal-distal sequence. In conclusion these results suggest that trunk motion is effective strategy for increasing performance of vertical jumping.

• Physical Therapy Korea
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• v.26 no.4
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• pp.53-62
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• 2019

Background: Shoulder function is achieved by the coordinated movements of the scapula, humerus, and thoracic spine, and shoulder disorders can be associated with altered scapular kinematics. The trunk plays an important role as the kinematic chain during arm elevation. Objects: The purpose of this study was to determine the effects of thoracic hyperkyphosis on scapular orientation and trunk motion. Methods: Thirty-one subjects (15 in the ideal thorax group and 16 in the thoracic hyperkyphosis group) performed right-arm abduction and adduction movements in an unconstrained plane. The scapular orientation and trunk motion were recorded using a motion analysis system. Results: Those subjects with thoracic hyperkyphosis displayed greater scapular posterior tilting at a $120^{\circ}$ shoulder elevation, greater scapular internal rotation throughout the arm raising phase, and greater trunk axial rotation at the upper ranges of the shoulder elevation, compared to those subjects with an ideal thorax (p<.05). Conclusion: Thoracic hyperkyphosis can cause scapular instability, greater trunk rotation and greater scapular posterior tilting, and may contribute to preventing the achievement of a full range of humeral abductions in an unconstrained plane.

• Korean Journal of Applied Biomechanics
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• v.17 no.4
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• pp.89-98
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• 2007

The purpose of this study was to evaluate the trunk motion and knee joint moment during deep stand to sit and sit to stand according to the trunk weight increase. These experimental subjects were 9 males, who had no skeletal muscular disease. They were performed a SATS(stand to sit), STS(sit to stand) according to the trunk weight increase. Trunk weight increase were classified into 4 bearing trunk weight of 0%, 8%, 16%, 24% of the subject' weight. 1-way(4) RM ANOVA is applied to get the difference of trunk displacement movements and knee joint moments according to he trunk weight increase. significant level of each experiment is set as $\alpha$=.05. 1. Significant difference was classified into 3 bearing trunk weight of 0%, 16%, 24% in maximum forward backward displacement of trunk COM(center of mass). Significant difference was classified into 4 bearing trunk weight of 0%, 8%, 16%, 24% in maximum upward downward displacement of trunk COM during the SATS, STS. 2. Significant difference was classified into 4 bearing trunk weight of 0%, 8%, 16%, 24% in maximum extension knee joint moment. Significant difference was classified into 2 bearing trunk weight of 0%, 16% in maximum internal rotation knee joint moment during the SATS, STS. Therefore we expect that biomechanical model of this study will used to study for mechanical characteristics of obese people.

• Journal of Korean Institute of Industrial Engineers
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• v.25 no.3
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• pp.393-403
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• 1999

In this research, a reach posture prediction based on a two-segment trunk model was made. Recently, reach posture prediction models have used inverse kinematics to provide a single posture that a person naturally takes, with a single segment trunk model that had some shortcomings. A two-segment trunk model was first developed with two links; pelvis link and lumbar-thoracic link. The former refers to the link from the hip joint to L5/S1 joint while the latter does the link from L5/S1 to the shoulder joint. Second, a reach prediction model was developed using the two-segment trunk model. As a result, more reliable equations for two-segment trunk motion were obtained, and the lean direction which refers to the movement direction of the trunk was not found to have a significant effect on the two-segment trunk motion. The results also showed that the hip joint is more preferred over L5/S1 to serve as a reference point for trunk models and the reach prediction model being developed predicted the real posture accurately.

• Journal of International Academy of Physical Therapy Research
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• v.11 no.4
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• pp.2229-2236
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• 2020

Background: Few comparative studies have been conducted on strengthening the anterior and posterior muscles of the trunk via lumbar stabilization exercises. Objectives: To compare the effects of forward leaning exercise and supine bridging exercise in stability exercise. Design: Randomized controlled clinical trial (single blind). Methods: Thirty subjects with spondylolisthesis were participated in this study. Fifteen subjects performed the bridging exercises and fifteen subjects performed the forward leaning exercises. Each exercise was held for ten seconds per repetition, and four repetitions were considered one sub-session. A total of four sub-sessions were performed in one full exercise session. The full exercise session required thirty minutes, including rest time. Trunk strength and range of motion and Oswestry disability index were measured. Results: Two weeks later, trunk flexion strength and trunk extension range of motion were significantly increased in the forward leaning exercise group than in the supine bridging group, trunk extension strength were significantly increased in the supine bridging exercise group than in the forward leaning group. After two weeks, the pain score was significantly lower in the forward leaning exercise group than in the supine bridging group. Conclusion: This study has shown that stabilization exercises are effective in increasing range of motion and strength in spondylolisthesis subjects. It was especially confirmed that the method of strengthening the anterior muscles of the trunk is more effective than the standard stabilization exercise method.

• Korean Journal of Applied Biomechanics
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• v.23 no.4
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• pp.307-318
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• 2013

The purpose of this study was to analyze the kinematic variables of glide kip motion on the uneven bars through a two-dimensional cinematography. Three expert female gymnastics players were involved in the data gathering process. The followings were concluded according to the results. The arm, trunk and leg segments were fully extended throughout the kip movement. The whole body center of gravity showed the biggest changes during 66 to 87% of the kip motion. During the kip phase, the horizontal displacement of the leg was greater than the vertical displacement the leg. Glide kip motion should be done in orders of upward movement of leg, forward movement of leg, upward movement of trunk and forward movement of trunk segment. It was found that trunk segment and hip joint movements showed bigger changes than those of leg segment and shoulder joint in the glide kip motion. The largest angular velocity of hip joint was shown in the middle of the kip Phase. In conclusion, effective kip movement could be resulted when the trunk was displaced posterior-upward direction with fast hip joint extension after the leg segment was elevated upward and thrusted forward in advance.