三つ這い位時体幹筋活動の筋電図学的分析

• Published in: 理学療法学 Vol. 30; no. 7; pp. 407 - 414
• Main Authors: 赤羽 秀徳, 望月 圭一, 髙橋 雅人, 尾﨑 心正, 田中 太郎
• Format: Journal Article
• Language: Japanese
• Published: 日本理学療法士学会 20.12.2003; Japanese Society of Physical Therapy
• Subjects: 三つ這い位; 体幹筋活動; 徒手筋力検査
• ISSN: 0289-3770; 2189-602X
• DOI: 10.15063/rigaku.kj00001019845

The main purposes of this study were to examine trunk muscle activities using EMG while raising the hand in all fours, and to compare the results with those of the grade 5 (normal) manual muscle testing (MMT5). This study also aimed at investigating whether each abdominal muscle works as prime or assistant mover in the MMT5. The surface EMG of the seven right trunk muscles were measured in nine healthy male subjects. Both of the external oblique (EO) and the internal oblique (IO) were activated against applied rotational movements of the trunk while raising the hand in all fours. The paraspinae muscle around T9 was more activated than L5/S1 on the raised hand side, and the L5/S1 were more activated than the T9 on the non-raised side. The ratio of activities of the rectus abdominis (RA) in this position to in MMT5 was lower compared with those of EO and IO. The ranges of the ratio were 0.2 to 0.6 in the case of the paraspinae muscle. It was suggested that the raising the hand in all fours could facilitate an appropriate muscle activity pattern for stabilization of the lumbar spine without increasing RA activities. Moreover, these results suggested that, as muscle endurance training requires about 15 to 40 per cent of the maximum voluntary contraction, the raising the hand in all fours could be effective in endurance training for back muscles, such as for the persons whose maximum voluntary contraction was weak, but equal to MMT5. The percentage of EO activities was too high so that there might be a lack of reliability in terms of measurement of MMT5 of the oblique. 本研究の主目的は，三つ這い位時の体幹筋活動部位を検討し，さらに三つ這い位時の体幹筋活動量を徒手筋力検査「Normal」（以下：MMT「N」）の筋活動量と比較・検討することである。副目的は，腹筋群のMMT試行時の，各筋の主動作筋としての活動と，補助筋として活動を検討することである。対象者は，健常男子9名とし，被験筋は，体幹右側の7筋とした。上肢挙上側の違いによる活動筋群の変化をみると，腹筋群では，腹斜筋群がほぼ三つ這い位時に体幹に加わる回旋負荷に抗する活動となっていた。一方背筋群では，胸腰移行部付近を境に，頭側では挙上側で，尾側では非挙上側で，より優位に筋活動がみられた。さらに，MMT「N」試行時に対する三つ這い位時の筋活動電位の比は，腹筋群では特に腹直筋の筋活動が，外腹斜筋，内服斜筋と比較し低かった。三つ這い位は，腹直筋を強調しないで腰部の安定性を高める運動となり得ることが示された。しかし，MMT比に示された外腹斜筋活動はかなり高い値となっており，腹斜筋に対するMMT手技の信頼性に疑問が生じた。背筋群ではMMT比がおよそ20〜60%の範囲にあり，これは筋持久性運動に必要とされる最大随意収縮の15〜40%の範囲に近似したものであるため，筋力が低下しており，最大筋力がMMT「N」試行時と等しい症例などには，三つ這い位が背筋群の筋持久性向上のための運動として有効となり得ることが示唆された。