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小西 優氏(第2期生)の研究論文が、European Society of Sports Traumatology Knee Surgery and Arthroscopy のオフィシャルジャーナルである Knee Surgery, Sports Traumatology, Arthroscopy 他に原著論文として掲載されました

スポーツチャレンジ研究助成第2期生 小西優氏(防衛大学所属)が取り組まれた助成対象研究3編が、European Society of Sports Traumatology Knee Surgery and Arthroscopyのオフィシャルジャーナルである Knee Surgery, Sports Traumatology, Arthroscopy 他に原著論文として掲載されました。


Relationship between quadriceps femoris muscle volume and muscle torque after anterior cruciate ligament rupture
Konishi Y, Oda T, Tsukazaki S, Kinugasa R, Hirose N, Fukubayashi T.
Knee Surg Sports Traumatol Arthrosc. 2011 Apr;
19(4):641-5. Epub 2010 Nov 24.
Relationship between quadriceps femoris muscle volume and muscle torque at least 18 months after anterior cruciate ligament reconstruction
Konishi Y, Oda T, Tsukazaki S, Kinugasa R, Fukubayashi T.
Scand J Med Sci Sports. 2011 May 23.
doi: 10.1111/j.1600-0838.2011.01332.x.
Relationship between muscle volume and muscle torque of the hamstrings after anterior cruciate ligament lesion
Konishi Y, Kinugasa R, Oda T, Tsukazaki S, Fukubayashi T.
Knee Surg Sports Traumatol Arthrosc.
2012 Jan 19.

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Relationship between quadriceps femoris muscle volume and muscle torque after anterior cruciate ligament rupture

Yu Konishi • Toshiaki Oda • Satoshi Tsukazaki •Ryuta Kinugasa • Norikazu Hirose •Toru Fukubayashi
Received: 23 March 2010 / Accepted: 4 November 2010 / Published online: 24 November 2010
Abstract

Purpose The purpose of this study was to obtain evidence to support the hypothesis that motor unit recruitment is reduced in the quadriceps femoris (QF) of patients with ACL rupture.
Methods We compared muscle torque per unit volume in the QF from injured and uninjured sides to normal subjects.
If high-threshold motor unit recruitment is reduced in patients with ACL rupture, this reduction will theoretically lead to a reduction in muscle torque per unit volume compared to the control group. The subjects included 22 patients with ACL rupture and 22 subjects with no history of knee injury. To identify the muscle torque per unit volume, the isokinetic peak torque was divided by QF volume which was obtained by MRI.
Results Tests revealed that the mean muscle torque per unit volume of the uninjured and injured sides was significantly lower than those of the control group.
Conclusion This study demonstrated that the values of the muscle torque per unit volume of both injured and uninjured sides of patients with ACL rupture were significantly lower than those of the control group, thereby providing indirect evidence of the hindrance of motor unit recruitment in these patients. The results of the present study also indicate that there may be bilateral QF weakness in patients with ACL rupture. Since persistent QF weakness is a significant barrier to effective rehabilitation in patients with ACL injuries, a better understanding of the underlying mechanisms will allow clinicians and scientists to develop more effective therapeutic strategies for patient rehabilitation.

Relationship between quadriceps femoris muscle volume and muscle torque at least 18 months after anterior cruciate ligament reconstruction

Y. Konishi1, T. Oda2,3, S. Tsukazaki4, R. Kinugasa5, T. Fukubayashi6 1Department of Physical Education, National Defence Academy, Kanagawa, Japan, 2Health and Life Sciences, Hyogo University of Teacher Education, Hyogo, Japan, 3Living Matter Simulation Research Team, RIKEN, Saitama, Japan, 4Department of Orthopedic Surgery, Japan Self Defense Force Yokosuka Hospital, Kanagawa, Japan, 5Department of Human Sciences, Kanagawa University Yokohama, Kanagawa, Japan, 6Department of Sports Science, Waseda University, Saitama, Japan Corresponding author: Yu Konishi, PhD, Department of Physical education, National Defence Academy, 1-10-20 Hashirimizu, Yokosuka City, Kanagawa 239-8686, Japan. E-mail: yu_57@yahoo.co.jp
Accepted for publication 11 April 2011
Abstract

The purpose of this study was to evaluate motor unit recruitment in the quadriceps femoris (QF) after anterior cruciate ligament (ACL) rupture and repair. Subjects included 24 patients at 18 months after ACL reconstruction and 22 control subjects with no history of knee injury. A series of cross-sectional magnetic resonance images were obtained to compare the QF of patients’ injured side with that of their uninjured sides and that of uninjured control subjects. Muscle torque per muscle volume was calculated as isokinetic peak torque divided by QF muscle volume (cm3).
The mean muscle torque per unit volume of the injured side of patients was not significantly different from that of the uninjured side or control subjects (one-way ANOVA) Results of the present study were contrary to the results of a previous study that evaluated patients at 12 months after ACL reconstruction.
The present study found that highthresholdmotor unit recruitment was restored at 18 months after ACL reconstruction. Thus, clinicians must develop techniques that increase the recruitment of highthreshold motor units in the QF from the period immediately after the injury until approximately 18 months after ACL reconstruction.

Relationship between muscle volume and muscle torque of the hamstrings after anterior cruciate ligament lesion

Yu Konishi • Ryuta Kinugasa • Toshiaki Oda •Satoshi Tsukazaki • Toru Fukubayashi
Received: 27 April 2011 / Accepted: 10 January 20120
Abstract

Purpose This study was conducted to identify factors other than morphological muscle strength factors that affect injured and uninjured sides of knee flexors with anterior cruciate ligament (ACL) lesions.
Methods The study population consisted of 22 patients with ACL lesions. Their hamstring muscle volume was measured on MRI, and muscle torque per muscle volume was calculated as the peak torque of knee flexion divided by hamstring muscle volume.
Results The mean muscle torque per unit volume of hamstrings in patients with ACL rupture was 0.09 ±0.02 Nm/cm3 at 60°/s and 0.08 ± 0.01 Nm/cm3 at 180°/s on the injured side, and 0.11 ± 0.02 Nm/cm3 at 60°/s and 0.08 ± 0.01 Nm/cm3 at 180°/s on the uninjured side. The mean muscle torque per unit volume of hamstrings in control subjects was 0.11 ± 0.02 Nm/cm3 at 60°/s and 0.08 ± 0.03 Nm/cm3 at 180°/s. One-factor ANOVA analysis found no significant differences between the three groups at either flexion velocity.
Conclusions Neurological dysfunction does not appear to exist in knee flexor muscles after ACL injury, unlike the quadriceps. Since the mechanism of muscle weakness will differ depending on the muscle, it is important for clinicians to take this discrepancy into consideration.
Level of evidence II.

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