Biomedical subjects

Toru Fukubayashi

Publications and source records attributed to Toru Fukubayashi.

9 recordsLinked to original sources

PubMed2007

Gender differences in knee kinematics and muscle activity during single limb drop landing.

The likelihood of sustaining an ACL injury in a noncontact situation is two to eight times greater for females than for males. However, the mechanism and risk factors of ACL injury are still unknown. We compared knee kinematics as well as electromyographic activity during landing between male and female athletes. Eighteen male athletes and nineteen female athletes participated in the experiment. The angular displacements of flexion/extension, valgus/varus, and internal/external tibial rotation, as well as the translational displacements of anterior/posterior tibial translation during single limb drop landing were calculated. Simultaneous electromyographical activity of the rectus femoris (RF) and hamstrings (Ham) was taken. During landing, internal tibial rotation of the females was significantly larger than that of the males, while differences were not observed in flexion, varus, valgus, and anterior tibial translation. Hamstrings/quadriceps ratio (HQR) for the 50 ms time period before foot contact was greater in males than in females. The mechanism of noncontact ACL injury during a single limb drop landing would be internal tibial rotation combined with valgus rotation of the knee. Increased internal tibial rotation combined with greater quadriceps activity and a low HQR could be one reason female athletes have a higher incidence of noncontact ACL injuries.

Adult↗

PubMed2006

Knee-flexion torque and morphology of the semitendinosus after ACL reconstruction.

PURPOSE: The present study aimed to clarify the relationship between deficits in knee-flexion torque and morphological changes in the semitendinosus muscle-tendon complex after harvesting the semitendinosus tendon for anterior cruciate ligament (ACL) reconstruction. METHODS: Isometric knee-flexion torque at 45 and 90 degrees of knee flexion was measured in limbs of 23 patients (22 +/- 4 yr) who underwent unilateral ACL reconstruction (12-43 months postoperation) using ipsilateral semitendinosus tendon. Magnetic resonance imaging scans were used to calculate the muscle volume and the muscle length of the semitendinosus and to confirm the presence of the regenerated semitendinosus tendon. RESULTS: The percentage of the knee-flexion torque of the ACL-reconstructed limb compared with that of the contralateral limb was lower at 90 degrees than at 45 degrees . The regeneration of the semitendinosus tendon-like structure was confirmed in 21 of the 23 patients. However, muscle volume and muscle length of the semitendinosus in the ACL-reconstructed limb were significantly smaller compared with in the contralateral limb. CONCLUSION: Deficits in knee-flexion torque at deep knee flexion were associated with the atrophy and shortening of the semitendinosus after harvesting the semitendinosus tendon for ACL reconstruction.

Adult↗

PubMed2005

Decrease of knee flexion torque in patients with ACL reconstruction: combined analysis of the architecture and function of the knee flexor muscles.

A decrease of deep knee flexion torque after anterior cruciate ligament (ACL) reconstruction, using a semitendinosus (and gracilis) tendon, has been reported. However, the cause of this weakness remains controversial. Architectural and functional differences in the knee flexor muscles influence this weakness. the fiber length of the semitendinosus, gracilis, semimembranosus, and biceps femoris were directly measured in six human cadavers. The flexion torque and EMG of the hamstrings were measured in both limbs of 16 patients (23+/-5 years) after ACL reconstruction (12-43 months post-operation), using ipsilateral semitendinosus tendon. Magnetic resonance imagings were taken, over both the thighs of those patients, to measure muscle volume and to confirm a state of semitendinosus tendon regeneration. The position of the musculotendinous junction of the semitendinosus was also analyzed. The fiber length of the semitendinosus and gracilis were three to four times longer than that of the semimembranosus and biceps femoris. The difference of flexion torque between the normal and ACL reconstructed limbs significantly increased as the knee flexion angle increased. The EMG value for the semimembranosus and biceps femoris of both limbs as well as the semitendinosus of the ACL reconstructed limbs, significantly reduced as the knee flexion angle was increased. The volume of the semitendinosus in the reconstructed limb was significantly smaller than in normal limbs. The regeneration of the semitendinosus tendon was confirmed in all subjects, and the musculotendinous junction position of the reconstructed limb in almost all subjects was found in further image from the knee joint space than that for the normal limb. The decrease of deep knee flexion torque, after ACL reconstruction, could be due to the atrophy and shortening of the semitendinosus after its tendon has been harvested, as well as the lack of compensation from the semimembranosus and biceps femoris, due to the architectural differences between the semitendinosus and the semimembranosus and biceps femoris.

Achilles Tendon↗

PubMed2003

Effect of harvesting the hamstrings tendon for anterior cruciate ligament reconstruction on the morphology and movement of the hamstrings muscle: a novel MRI technique.

This study evaluated intramuscular movement of hamstrings muscle after reconstruction of the ACL with a hamstrings tendon graft. The movement of the muscles during knee flexion was measured using a novel MRI technique called the "tagging snapshot" technique, which labels multiple tagging bands within the musculature. Eleven patients who underwent ACL reconstruction using autogenous semitendinosus and gracilis tendons were studied. The difference in the maximum active knee flexion angle between the ACL-reconstructed and the intact knee was calculated as knee flexion lag. Knee flexion strength was measured in 8 of the 11 patients. The semitendinosus muscle of the ACL-reconstructed knee exhibited three different morphological patterns; group I, similar shape to the intact knee with distal tendonlike structures; group II, smaller proximally than the intact knee with distal tendonlike structures; and group III, considerably smaller proximally than the intact knee without distal tendonlike structures. Each group was associated with a different knee flexion lag and different knee flexion strength. Our results indicated that the effect of hamstrings tendon harvest on knee function is not uniform.

Adult↗

PubMed2003

Gamma loop dysfunction in quadriceps on the contralateral side in patients with ruptured ACL.

PURPOSE: The aim of our study was to test for any neurophysiological abnormality in the gamma loop in the quadriceps femoris muscle on the uninjured side of patients with unilateral rupture of the anterior cruciate ligament (ACL). METHODS: Maximal voluntary contraction of knee extension and integrated electromyography (I-EMG) of the vastus medialis, vastus lateralis, and rectus femoris were measured in the uninjured limb of 13 patients with unilateral ACL rupture and 10 normal subjects, before and after 20-min vibration stimulation applied to the infrapatellar tendon. RESULTS: The mean percentage changes of maximal voluntary contraction and I-EMG in quadriceps femoris of the uninjured side of patients with ACL rupture were significantly different from those of the control group. Maximal voluntary contraction and I-EMG after prolonged vibration stimulation did not decrease as much as those of the control group even though the same protocol of vibration stimulation was applied. CONCLUSION: The abnormal response to prolonged vibration stimulation could represent abnormal gamma loop in the quadriceps femoris muscle of the uninjured side in patients with ACL rupture since the normal response of maximal voluntary contraction and I-EMG to prolonged vibration stimulation could not be evoked without normal function of the gamma loop.

Adolescent↗

PubMed2003

Acupuncture and responses of immunologic and endocrine markers during competition.

INTRODUCTION: Acupuncture is used to modulate the physical well-being of athletes in Asian countries. However, there is little information on the immediate effects of acupuncture treatment on physiological or psychological responses to exercise. PURPOSE: The purpose of this study was to examine the effect of acupuncture treatment on the physical well-being of elite female soccer players during a competition period. METHODS: Subjects were divided into two groups: those who received acupuncture treatment (18.1 +/- 2.3 yr [+/-SD], N = 9) and a control group (17.7 +/- 2.8 yr, N = 12). In the treatment group, acupuncture stimulus was applied at LI 4 (Goukoku), ST 36 (Ashi-sanri) for 20 min, and ST 6 (Kyosya), LU 6 (Ko-sai) points for 15 min 4 h after the game every night during the competition period. The measured parameters included salivary secretory immunoglobulin A (SIgA) level, cortisol level in saliva, subjective rating of physical well-being, and profile of mood states (POMS). RESULTS: The following were the main results: 1). Exercise-induced decrease of salivary SIgA and increase of salivary cortisol were inhibited by acupuncture. 2). Acupuncture improved subjective rating of muscle tension and fatigue. 3). The POMS score was modulated by acupuncture. CONCLUSION: These results support the effectiveness of acupuncture for physical and mental well-being of athletes.

Acupuncture Therapy↗

PubMed2003

Effects of lidocaine into knee on QF strength and EMG in patients with ACL lesion.

PURPOSE: In our previous study, we found that injection of lidocaine into intact knees reduced the maximal voluntary contraction (MVC) and integrated electromyogram (I-EMG) of the quadriceps femoris (QF). This study was designed to investigate changes in the MVC and I-EMG of the QF in response to lidocaine, in patients with anterior cruciate ligament (ACL) lesion, to evaluate alpha-motoneuron activity innervating the QF. METHODS: The MVC of knee extension and I-EMG of the vastus medialis (VM), vastus lateralis (VL), and rectus femoris (RF) muscles were measured in eight patients with ruptured ACL, before and after lidocaine injection into the knee. RESULTS: There were no significant differences between preinjection and postinjection values of MVC (preinjection: 167 +/- 49 N.m; postinjection: 164 +/- 55 N.m) and I-EMG (preinjection: VL: 0.11 +/- 0.06, VM: 0.13 +/- 0.10, RF: 0.09 +/- 0.04) (postinjection: VL: 0.12 +/- 0.07, VM: 0.13 +/- 0.10, RF: 0.09 +/- 0.05). CONCLUSION: Our results indicated that hindrance of afferent feedback from the knee in patients with ACL rupture did not significantly change alpha-motoneuron activity. Lidocaine injection into the knee joint of the subjects in this study only attenuated afferent feedback from mechanoreceptors in the knee joint cavity, but not in the ACL, as afferent feedback from ACL was already lost due to ACL rupture. This indicated that attenuation of afferent feedback from mechanoreceptors in the knee joint cavity other than the ACL did not significantly decrease the activity of alpha-motoneurons innervating the QF during MVC exertion. Therefore, our findings provide evidence that afferent feedback from the ACL has a major influence on the MVC exertion of the QF.

Adolescent↗

PubMed2002

Magnetic resonance imaging of Osgood-Schlatter disease: the course of the disease.

OBJECTIVE: The purpose of this study was to clarify the nature of Osgood-Schlatter disease (OSD) using MR images. DESIGN: Thirty boys (40 knees) with OSD diagnosed by clinical symptoms and signs were investigated with MRI. Longitudinal evaluation was undertaken in 22 patients and the mean follow-up was 1.5+/-0.9 years. MR examinations were performed at least every 6 months in most cases. When a patient's symptoms changed, MRI was repeated and in cases where the initial MR examination showed an early or progressive stage of OSD, MRI was undertaken every month where possible. All MR examinations were performed in the sagittal plane with a 0.2 T imager. RESULTS: MR images were classified into five stages as follows: normal, early, progressive, terminal and healing. The stage of 11 knees (28%) did not change during the course of the study and 21 knees (53%) showed a change of at least one stage. Eight knees (20%) did not have follow-up MR studies. The initial MR examination was normal in nine knees. Eight knees were at the early stage at presentation. MR images showed edema-like changes around the tibial tuberosity. Ten knees were classified as in the progressive stage at the initial presentation and six knees were classified in this group during progression on follow-up MRI. MR images showed partial avulsion of the secondary ossification center, which was seen to be being pulled proximally. Eleven knees were at the terminal stage on presentation, where the avulsed parts of the secondary ossification center had become completely separated. Two knees were classified as in the healing stage at presentation and 19 knees progressed to the healing stage from the normal, early and progressive stages. The MR images showed the separated part that did not create the ossicle had recovered by osseous healing. On the other hand, radiographs of the early stage appeared almost normal, and in the progressive stage could not show the avulsed parts. CONCLUSIONS: We clarified the progress of OSD with MRI. The process of OSD started from the apophyseal stage and a tear appeared in the secondary ossification center, widening to an opened shell-like shape. This damage progressed to an ossicle in some cases. In short, the ossicle was formed from an avulsed portion. It was very difficult to show the course of OSD with radiography. MR images were especially useful for revealing early and progressive lesions of OSD.

Adolescent↗

PubMed2002

Possible mechanism of quadriceps femoris weakness in patients with ruptured anterior cruciate ligament.

PURPOSE: The purpose of this study was to test the hypothesis that loss of afferent feedback due to rupture of anterior cruciate ligament (ACL) is the cause of quadriceps femoris (QF) weakness through gamma loop. Two experiments were designed to prove our hypothesis. METHODS: In experiment 1, the maximal voluntary contraction (MVC) of knee extension and integrated electromyogram (I-EMG) of vastus medialis (VM), vastus lateralis (VL), and rectus femoris (RF) were measured in 13 patients with ruptured ACL and 7 healthy volunteers before and after injection of anesthetic agent into the knee. In experiment 2, MVC of knee extension and I-EMG of the VM, VL, and RF were measured in 13 patients with ruptured ACL, 7 knee-anesthetized healthy subjects, and 12 normal subjects, before and after 20-min vibration stimulation applied to the infrapatellar tendon. RESULTS: The results of experiment 1 revealed that injection of anesthetic agent into the knee capsule resulted in significant decrease of MVC and I-EMGs. In experiment 2, the mean percentage change of MVC in the control group was significantly lower than that in the other two groups. There was no significant difference between knee-anesthetized group and patients with ruptured ACL. The mean percentage change of I-EMG showed a pattern similar to that of MVC. CONCLUSION: Our results suggest that loss of feedback from mechanoreceptors in ACL is the underlying mechanism of weakness of QF in patients with ACL lesion. This conclusion is based on chronic suppression of recruitment of high-threshold motor units during voluntary contraction because ACL lesion leads to chronic reduction in Ia-feedback to muscles around the knee due to a lack of feedback from ACL to gamma motor neurons.

Adolescent↗