著者

Osamu Yanagisawa Tomoki Oshikawa Naoto Matsunaga Gen Adachi Koji Kaneoka

出版者

Japanese Society for Magnetic Resonance in Medicine

雑誌

Magnetic Resonance in Medical Sciences (ISSN:13473182)

巻号頁・発行日

pp.mp.2020-0052, (Released:2020-09-01)

参考文献数

20

被引用文献数

3

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Purpose: We aimed to evaluate the acute physiological effects of high-load deadlift exercise on the lumbar intervertebral discs using MR diffusion-weighted imaging (DWI).Methods: Fifteen volunteers (11 men and 4 women; 23.2 ± 3.3 years) without lumbar intervertebral disc degeneration performed deadlift exercise (70% of 1 repetition maximum, 6 repetitions, 5 sets, 90 s rest between sets) using a Smith machine. Sagittal MR diffusion-weighted images of the lumbar intervertebral discs were obtained using a 1.5-Tesla MR system with a spine coil before and immediately after the exercise. We calculated apparent diffusion coefficient (ADC; an index of water movement) of the nucleus pulposus from diffusion weighted images at all lumbar intervertebral discs (L1/2 through L5/S1).Results: All lumbar intervertebral discs showed significantly decreased ADC values immediately after deadlift exercise (L1/2, −2.8%; L2/3, −2.1%; L3/4, −2.8%; L4/5, −4.9%; L5/S1, −6.2%; P < 0.01). In addition, the rate of ADC decrease of the L5/S1 disc was significantly greater than those of the L1/2 (P = 0.017), L2/3 (P < 0.01), and L3/4 (P = 0.02) discs.Conclusion: The movement of water molecules within the lumbar intervertebral discs is suppressed by high-load deadlift exercise, which would be attributed to mechanical stress on the lumbar intervertebral discs during deadlift exercise. In particular, the L5/S1 disc is subjected to greater mechanical stress than the other lumbar intervertebral discs.

著者

Osamu Yanagisawa Hidenori Taniguchi

出版者

The Society of Physical Therapy Science

雑誌

Journal of Physical Therapy Science (ISSN:09155287)

巻号頁・発行日

vol.32, no.9, pp.578-583, 2020 (Released:2020-09-01)

参考文献数

23

被引用文献数

7

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[Purpose] To evaluate the relationship between stride length during a pitch and maximal ball velocity and define the determinants of stride length in collegiate baseball pitchers. [Participants and Methods] Eighteen collegiate baseball pitchers participated in this study. Using a standard tape measure, the distance between each participant’s legs was measured after maximal abduction of both hip joints in a standing position. The pitchers threw fastballs on an indoor pitching mound at an official pitching distance. The throwing motion was recorded with four high-speed video cameras (240 Hz), while the ball velocity was measured using a radar gun. The stride length at foot contact was calculated at the maximal ball velocity using a three-dimensional motion analysis system. [Results] The maximal ball velocity (mean 129.8 km/h) had a significant positive correlation with the absolute stride length during a pitch (r=0.55), but no correlation with the relative stride length (% body height, % lower extremity length, and % maximal open legs’ width). Stride length during a pitch did not significantly correlate with the pitcher’s body height, lower extremity length, and maximal open legs’ width. [Conclusion] A longer stride length contributes to a higher ball velocity in collegiate baseball pitchers.

著者

Osamu Yanagisawa Genki Futatsubashi Hidenori Taniguchi

出版者

The Society of Physical Therapy Science

雑誌

Journal of Physical Therapy Science (ISSN:09155287)

巻号頁・発行日

vol.30, no.1, pp.58-62, 2018 (Released:2018-01-27)

参考文献数

16

被引用文献数

7

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[Purpose] To evaluate the side-to-side difference in dynamic unilateral balance ability and to determine the correlation of the balance ability with pitching performance in collegiate baseball pitchers. [Subjects and Methods] Twenty-five Japanese collegiate baseball pitchers participated in this study. Dynamic balance ability during a unilateral stance was bilaterally evaluated using the star excursion balance test (SEBT). The pitchers threw 20 fastballs at an official pitching distance; the maximal ball velocity and pitching accuracy (the number of strike/20 pitches × 100) were assessed. Side-to-side difference in scores of SEBT was assessed using a paired t-test. Correlations between SEBT scores and pitching performance were evaluated for both legs using a Pearson’s correlation analysis. [Results] The pivot side showed significantly higher score of the SEBT in the anteromedial direction than the stride side. On the other hand, the SEBT scores in the pivot and stride legs did not have significant correlations with maximal ball velocity and pitching accuracy. [Conclusion] These findings suggest that marked side-to-side difference does not exist in the dynamic unilateral balance ability of collegiate baseball pitchers and that the dynamic unilateral balance ability of each leg is not directly related to maximal ball velocity and pitching accuracy.