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

Gen Adachi Tomoki Oshikawa Hiroshi Akuzawa Koji Kaneoka

出版者

The University of Tokushima Faculty of Medicine

雑誌

The Journal of Medical Investigation (ISSN:13431420)

巻号頁・発行日

vol.67, no.3.4, pp.274-279, 2020 (Released:2020-11-05)

参考文献数

32

被引用文献数

2

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The purpose of this study was to clarify the influence of different postures on the activity of the shoulder girdle and lower back muscles while using a smartphone. Sixteen healthy male participants maintained two postures while using a smartphone : a good posture in which the tragus and acromion were closer to the vertical line passing through the greater trochanter, and a poor posture in which the tragus and acromion were farther from the vertical line passing through the greater trochanter. The target muscles were the rhomboid major (Rhom), upper trapezius, middle trapezius, lower trapezius (LT), lumbar erector spinae (LES), and lumbar multifidus (LMF). The activities of the Rhom and LT were significantly lower with poor posture than those with good posture. The activities of LES and LMF were significantly higher with poor posture than those with good posture. The results of this study indicated that poor posture was associated with hypoactivity of the shoulder girdle muscles and hyperactivity of the lower back muscles when compared with good posture. Poor posture for prolonged periods while using a smartphone would lead to malfunction of the shoulder girdle muscles and musculofascial lower back pain. J. Med. Invest. 67 : 274-279, August, 2020