Itsuo Shiina

Trunk Muscle Activity During Lumbar Stabilization Exercises on Both a Stable and Unstable Surface

STUDY DESIGN Controlled laboratory study. OBJECTIVES To clarify whether differences in surface stability influence trunk muscle activity. BACKGROUND Lumbar stabilization exercises on unstable surfaces are performed widely. One perceived advantage in performing stabilization exercises on unstable surfaces is the potential for increased muscular demand. However, there is little evidence in the literature to help establish whether this assumption is correct. METHODS Nine healthy male subjects performed lumbar stabilization exercises. Pairs of intramuscular fine-wire or surface electrodes were used to record the electromyographic signal amplitude of the rectus abdominis, the external obliques, the transversus abdominis, the erector spinae, and lumbar multifidus. Five exercises were performed on the floor and on an unstable surface: elbow-toe, hand-knee, curl-up, side bridge, and back bridge. The EMG data were normalized as the percentage of the maximum voluntary contraction, and data between doing each exercise on the stable versus unstable surface were compared using a Wilcoxon signed-rank test. RESULTS With the elbow-toe exercise, the activity level for all muscles was enhanced when performed on the unstable surface. When performing the hand-knee and side bridge exercises, activity level of the more global muscles was enhanced when performed on an unstable surface. Performing the curl-up exercise on an unstable surface, increased the activity of the external obliques but reduced transversus abdominis activation. CONCLUSION This study indicates that lumbar stabilization exercises on an unstable surface enhanced the activities of trunk muscles, except for the back bridge exercise.

Electromyographic Analysis of Transversus Abdominis and Lumbar Multifidus Using Wire Electrodes During Lumbar Stabilization Exercises

STUDY DESIGN Experimental laboratory study. OBJECTIVES To measure trunk muscle activity using wire electrodes during lumbar stabilization exercises and to examine if more effective exercises to activate the deep trunk muscles (local muscles) exist. BACKGROUND Lumbar stabilization exercises are performed to improve motor control of trunk muscles. However, the magnitude of activation of local muscles during lumbar stabilization exercises is not clear. METHODS Nine healthy men with no history of lumbar spine disorders participated in the study. Fine-wire electrodes were inserted into the transversus abdominis (TrA) and lumbar multifidus, bilaterally. In addition, surface electrodes were attached to the rectus abdominis, external obliques, and erector spinae, bilaterally. Electromyographic signal amplitude was measured during the following exercises: elbow-toe, hand-knee, back bridge, side bridge, and curl-up. Two-way analyses of variance were used to compare muscle activity level among exercises and between sides for each muscle. RESULTS The exercise showing the greatest activity level for the TrA was elbow-toe exercise with contralateral arm and leg lift. In addition, for the TrA, a significant side-to-side difference in activation level was demonstrated for 7 of the 11 exercises that were performed. The activity level of the multifidus was greatest during the back bridge exercises. The curl-up exercise generated the highest activity level for the rectus abdominis and the back bridge, with single-leg lift exercises generating the highest erector spinae activity. CONCLUSIONS The exercises investigated in this study resulted in a wide range of effort level for all 5 muscles monitored. Many of the exercises also resulted in an asymmetrical (right versus left side) activation level for a muscle, including the TrA.

Femoral nerve palsy caused by a huge iliopectineal synovitis extending to the iliac fossa in a rheumatoid arthritis case.

We report on a 54-year-old woman with rheumatoid arthritis who had severe femoral nerve palsy affected by a distended synovium in the hip joint. Surgical exploration demonstrated a perforation of the iliopectineal bursa connecting with the hip joint. The patient fully recovered from femoral nerve palsy after surgery. It was considered that synovitis of the hip joint had developed following huge iliopectineal bursitis.

COMPARISON OF THE ACTIVITIES OF THE DEEP TRUNK MUSCLES MEASURED USING INTRAMUSCULAR AND SURFACE ELECTROMYOGRAPHY

Surface electromyography (EMG) has been used to estimate deep trunk muscle activity. However, it remains unknown whether surface EMG provides an accurate estimation of this activity. The purposes of this study were to compare surface and intramuscular EMG activity measurements and investigate the efficacy of surface EMG measurement for the transversus abdominis (TrA) and the multifidus (MF) muscles. Eight healthy men participated in the study. TrA and MF activities were simultaneously measured by both intramuscular and surface EMG during isometric trunk exercises. Spearman correlation coefficients for the relationship between the two activity measurements for the right TrA, left TrA, right MF, and left MF were 0.55, 0.36, 0.67, and 0.79, respectively. For the TrA, Bland–Altman plots revealed that mean differences between measurements obtained by intramuscular EMG and surface EMG were not close to zero, with a systematic bias toward higher surface EMG values. In conclusion, surface and intramuscular EMG ac...

Trunk muscle activity while lifting objects of unexpected weight

OBJECTIVE To determine trunk muscle activity when lifting an object of greater weight than expected, which may contribute to the development of low back pain. DESIGN Electromyographic evaluation of trunk muscle activity. SETTING University of Tsukuba, Spine laboratory. PARTICIPANTS Eleven healthy men with a mean age of 24 (SD 2) years. INTERVENTIONS Trunk muscle activity was measured when subjects lifted an object with their right arm in immediate response to a light stimulus. Surface and wire electrodes were used to measure the activity of the rectus abdominis, external oblique and erector spinae muscles, and the transversus abdominis and lumbar multifidus muscles, respectively. The lifting tests were performed in three different settings: lifting an expected 1-kg object, lifting an unexpected 4-kg object (erroneously expected to weigh 1 kg), and lifting an expected 4-kg object. MAIN OUTCOME MEASURES The muscle activity induced when subjects lifted objects of different weights was compared by calculating the root mean square (RMS) of muscle activity at rest and % maximum voluntary contraction. RESULTS When the subjects were aware of the weight of the object to be lifted, the activity of the external oblique, transversus abdominis, erector spinae and lumbar multifidus muscles increased immediately after lifting. When the subjects were not aware of the weight of the object to be lifted, the increase in muscle activity was delayed (P<0.05). CONCLUSIONS Trunk muscles may not be able to function appropriately when individuals lift an object that is much heavier than expected.

Abdominal Muscle Activity During a Standing Long Jump

STUDY DESIGN Experimental laboratory study. OBJECTIVES To measure the activation patterns (onset and magnitude) of the abdominal muscles during a standing long jump using wire and surface electromyography. BACKGROUND Activation patterns of the abdominal muscles, especially the deep muscles such as the transversus abdominis (TrA), have yet to be examined during full-body movements such as jumping. METHODS Thirteen healthy men participated. Wire electrodes were inserted into the TrA with the guidance of ultrasonography, and surface electrodes were attached to the skin overlying the rectus abdominis (RA) and external oblique (EO). Electromyographic signals and video images were recorded while each subject performed a standing long jump. The jump task was divided into 3 phases: preparation, push-off, and float. For each muscle, activation onset relative to the onset of the RA and normalized muscle activation levels (percent maximum voluntary contraction) were analyzed during each phase. Comparisons between muscles and phases were assessed using 2-way analyses of variance. RESULTS The onset times of the TrA and EO relative to the onset of the RA were -0.13 ? 0.17 seconds and -0.02 ? 0.07 seconds, respectively. Onset of TrA activation was earlier than that of the EO. The activation levels of all 3 muscles were significantly greater during the push-off phase than during the preparation and float phases. CONCLUSION Consistent with previously published trunk-perturbation studies in healthy persons, the TrA was activated prior to the RA and EO. Additionally, the highest muscle activation levels were observed during the push-off phase.

Treatment for Lateral Flexion Fracture Dislocation of the Cervical Spine:Report of Two Cases

The injury mechanism of traumatic cervical spine injury varies, and Allen et al. divide cervical spine injuries into 6 types based on the direction of external force at the time of injury. In this report, we present 2 cases as Lateral Flexion Stage 2. A 51-year-old male (Case 1) was injured in a traffic accident. His conscious level was JCS III-200, and he was found to have a Frankel Grade of B. X-ray revealed a C5/6 fracture dislocation injury of Lateral Flexion Stage 2. We were unable to obtain good reduction. We planned to perform posterior fusion using a cervical spine pedicle screw but could not perform the procedure due to the patient’s poor general condition. A 32-year-old male (Case 2) was injured as a result of being hit by a steel sheet. He had Frankel Grade D paralysis. X-ray revealed a C5/6 fracture dislocation injury of Lateral Flexion Stage 2. We did not perform manual reduction. We performed posterior fixation, anterior decompression and anterior fixation. Bone union was confirmed, and the patient was able to return to work. In cases of this type of fracture dislocation of the cervical spine, the supporting structures of the spinal column circumferentially rupture and induce high instability. Since closed reduction is sometimes difficult and involves risk, strong internal fixation might be recommended.