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  • Author: Yukio Urabe x
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Yukio Urabe, Mitsuo Ochi and Kiyoshi Onari

Objective:

To investigate changes in muscle strength in the lower extremity after ACL reconstruction.

Design:

Prospective case series.

Dependent Variables:

Isokinetic muscle strength measured in 6 movements (hip extension/flexion, hip adduction/abduction, knee extension/flexion) and circumference of the thigh/calf.

Setting:

Clinic and home.

Patients:

44 (24 men, 20 women) between the ages of 16 and 47 years with an ACL rupture. All underwent reconstruction via a semitendinosus autograft.

Main Outcome Measures:

The peak torque for each joint movement was recorded. Repeated-measures ANOVA and power analysis were conducted to detect significant interaction effects.

Results:

The decline of muscle strength after ACL reconstruction remained not only in the knee extensors and flexors but also in the hip adductors.

Conclusion:

Rehabilitation programs that address the behavioral patterns and physiological characteristics of an ACL injury will benefit the athlete’s whole body and lead to a full recovery.

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Junpei Sasadai, Yukio Urabe, Noriaki Maeda, Hiroshi Shinohara and Eri Fujii

Context:

Posterior ankle impingement syndrome is a common disorder in soccer players and ballet dancers. In soccer players, it is caused by the repetitive stress of ankle plantar flexion due to instep kicking. Protective ankle dorsiflexion taping is recommended with the belief that it prevents posterior ankle impingement. However, the relationship between ankle taping and ball-kicking performance remains unclear.

Objective:

To demonstrate the relationship between the restrictions of ankle taping and performance of an instep kick in soccer.

Design:

Laboratory-based repeated-measures.

Setting:

University laboratory.

Participants:

11 male university soccer players.

Intervention:

The subjects’ ankle plantar flexion was limited by taping. Four angles of planter flexion (0°, 15°, 30°, and without taping) were formed by gradation limitation. The subjects performed maximal instep kicks at each angle.

Main Outcome Measures:

The movements of the kicking legs and the ball were captured using 3 high-speed cameras at 200 Hz. The direct linear-transformation method was used to obtain 3-dimensional coordinates using a digitizing system. Passive ankle plantar-flexion angle, maximal plantar-flexion angle at ball impact, ball velocity, and foot velocity were measured. The data were compared among 4 conditions using repeated-measures ANOVA, and the correlations between ball velocity and foot velocity and between ball velocity and toe velocity were calculated.

Results:

Ankle dorsiflexion taping could gradually limit both passive plantar flexion and plantar flexion at the impact. Furthermore, limitation of 0° and 15° reduced the ball velocity generated by instep kicks.

Conclusion:

Plantar-flexion-limiting taping at 30° has a potential to prevent posterior ankle impingement without decreasing the ball velocity generated by soccer instep kicks.

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Hiromune Obayashi, Yukio Urabe, Yuki Yamanaka and Ryo Okuma

Design:

Randomized controlled study.

Setting:

Laboratory.

Participants:

26 healthy swimmers randomly assigned to an exercise (n = 13; Ex) or control group (n = 13; Cont).

Intervention:

The Ex group performed respiratory-muscle exercises for 10 min thrice a week for 4 wk.

Context:

Respiratory-muscle exercises are used not only in the rehabilitation of patients with respiratory disease but also in endurance training for athletes. Respiration involves the back and abdominal muscles. These muscles are 1 of the elements responsible for posture control, which is integral to injury prevention and physical performance. However, the effects of respiratory-muscle exercise on posture remain unclear.

Objective:

To examine the potential of respiratory-muscle exercise for improving posture.

Main Outcome Measures:

Spinal curvature, pulmonary function, and trunk-muscle strength were measured for both the groups at baseline and after 4 wk. The data were compared between the Ex and Cont groups with Mann–Whitney U test and preintervention and postintervention within groups with a Wilcoxon signed rank-sum test.

Results and Conclusion:

The spinal curvature was significantly different in the Ex group, indicating a decrease in the thoracic (−13.1%, P < .01) and lumbar (−17.7%, P < .05) angles. The Ex group presented with lower thoracic (−8.6%) and lumbar (−20.9%) angles at postexercise than the Cont group (P < .05). With respect to trunk-muscle strength, only trunk-flexion strength significantly increased from pretest to posttest in the Ex group (P < .05). For pulmonary function, forced vital capacity and forced expiratory volume in 1.0 s were significantly increased after 4 wk in the Ex group (P < .05). The results suggest that respiratory-muscle exercise straightened the spine, leading to good posture control, possibly because of contraction of abdominal muscles.

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Yukio Takihara, Yukio Urabe, Gaston Ariel Nishiwaki, Kosuke Tanaka and Koji Miyashita

Context:

Back-muscle fatigue and lumbar curvature are related to low back pain, but the relation between them is unknown.

Objective:

To clarify whether lumbar curvature changes with back-muscle fatigue.

Design:

Prospective pseudorandomized.

Setting:

Laboratory.

Participants:

13 healthy men without low back pain.

Intervention:

To induce back-muscle fatigue, subjects performed a repetitive prone back-extension exercise from 45° to 0° until exhaustion and then rested 10 min. They performed this exercise 3 times.

Main Outcome Measures:

Before the trial and after each exercise, lumbar curvature was measured with a Spinal Mouse.

Results:

After back-muscle fatigue, lumbar curvature decreased significantly (P < .01). This decrease occurred at L4–S1, which was defined as the lower spine. On the contrary, curvature of the upper lumbar spine, at Th12–L4, did not decrease.

Conclusion:

Lumbar curvature, especially the lower portion, decreased with back-muscle fatigue induced by prone back-extension exercise.

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Noriaki Maeda, Yukio Urabe, Junpei Sasadai, Akira Miyamoto, Masahito Murakami and Junichi Kato

Context:

Whole-body-vibration (WBV) stimulus equipment has been used as a new training method for health promotion. Its use in the clinic has expanded to the field of sports and rehabilitation for disabled patients. WBV training is rapidly gaining popularity in health and fitness centers as an alternative method for improving muscle performance. Acute positive effects of WBV have been shown on lower-extremity muscle power and vertical-jump ability; however, there have not been any studies focusing on the long-term effects of WBV for trunk muscle and dynamic balance.

Objective:

To investigate the effects of an 8-wk program of WBV in combination with trunk-muscle training on muscle performance in healthy, untrained adults.

Design:

Laboratory-based, repeated-measures study.

Setting:

University laboratory.

Participants:

20 healthy university men.

Intervention:

Participants were randomly assigned to a WBV or non-WBV group. The WBV group performed a trunk-muscle-training program in combination with WBV; the non-WBV group performed the same muscle-training program without WBV for 8 wk.

Main Outcome Measures:

In the pre- and posttraining period, the participants were evaluated using the Functional Movement Screen (FMS), Y Balance Test (Y-test) (anterior, posteromedial, and posterolateral reach), trunk-muscle isometric strength (flexor, extensor, and flexor:extensor ratio), squat jump, and countermovement jump.

Results:

The WBV group had greater improvement than the non-WBV group in both trunk-flexor muscle strength (P = .02) and the Y-test (anterior reach) (P = .004) between pre- and posttraining.

Conclusion:

Adding WBV to a trunk-muscle-strengthening program may improve trunk-flexor isometric strength and anterior reach during the Y-test more than training without WBV. The WBV protocol used in this study had no significant impact on FMS scores, squat jumping, countermovement jumping, trunk-extensor isometric strength, or trunk flexor:extensor ratio.