Published papers

This study investigated the relationship between push-in meter (PM) and ultrasound strain elastography (USE) for biceps brachii (BB) muscle hardness. BB hardness of 21 young men was assessed by PM and USE during rest and isometric contractions of six different intensities (15, 30, 45, 60, 75, 90% of maximal voluntary contraction: MVC) at 30°, 60° and 90° elbow flexion. Muscle hardness (E) was calculated from the force–displacement relationship in PM, and strain ratio (SR) between an acoustic coupler (elastic modulus: 22.6 kPa) and different regions of interest (ROIs) in BB was calculated and converted to Young’s modulus (YM) in USE. In resting muscle, E was 26.1 ± 6.4 kPa, and SR and YM for the whole BB was 0.88 ± 0.4 and 30.8 ± 12.8 kPa, respectively. A significant (p < 0.01) correlation was evident between E and logarithmical transformed SR (LTSR) for the ROI of whole BB (r = − 0.626), and E and converted YM (r = 0.615). E increased approximately ninefold from resting to 90% MVC, and E and LTSR (r = − 0.732 to − 0.880), and E and converted YM for the SR above 0.1 were correlated (r = 0.599–0.768, p < 0.01). These results suggest that muscle hardness values obtained by PM and USE are comparable.

押圧時の変位－力関係の波形から上腕二頭筋の筋硬度推定法を検討した。2層弾性モデルによる推定の信頼範囲を回帰直線の決定係数およびPieacewise Linear Regression法から計算した。その結果直線性が維持される範囲は個人の筋厚の25-30％と考えられた。この考え方によって、個人間の組織量を規格化した筋硬度値の比較が可能となる。

筋張力と筋硬度の関係を検証するため、筋の長さ-張力関係全体を網羅して両者の関係をみた。その結果、よく知られている逆U字型の筋の長さ-張力関係および、静止張力と活動張力の和で示されえる全張力の関係において、張力を硬さに置き換えた長さ-硬さ関係がほぼ同様に成り立つことが示された。

蛙摘出筋を用い、伸張・収縮等の条件における長軸方向の張力変化と筋腹への垂直押圧による反力の関係を検討した。伸張時の張力増加とともに、押し込み反力も増加を示し、張力と反力の関係は、直線的傾向を示した。また、収縮張力の大小に、押し込み反力も比例関係を示し、収縮張力と押し込み反力にも直線関係が見出せた。

Eccentric Exercise後の筋硬度変化について、HORIKWAらの押圧法によるmuscle hardness計測によって評価した。筋損傷後には肘屈筋の短縮に伴い、筋硬度が肘伸展位で有意に増加し、RANGの減少といったstiffness変化と関係が示された。また４日目以後のRelax位での硬度上昇から、Muscle Swellingの関与も示唆された。

「2040年に向けた高等教育のグランドデザイン」（中央教育審議会，2018）が答申され，今後の大学体育の進むべき方向性について検討を行った．現状の大学体育が扱う「人間形成」「健康教育」「スポーツ文化の理解と実践」の更なる課題に加え、「教学マネジメントの推進」「STEAM 教育に体育・スポーツ教育を加えた総合的な教育の構築」が今後の重視すべき視点と考えられる．

上腕二頭筋(BB)と上腕筋(BA)のせん断弾性率とその2つの合計(BB+BA)および尿中タイチンN末端フラグメント(UTF)、最大随意等尺性収縮（MVC）およびその他の間接マーカーの関係を調査した。その結果、BB および BAのせん断弾性率が、UTF、MVC、ROM よりも筋肉損傷に関するより正確な情報を提供する可能性が示された。

Background/Objectives: In this study, we aimed to examine the effect of creatine monohydrate (CrM) supplementation on recovery from eccentric exercise-induced muscle damage (EIMD) in diverse populations, including different sexes and age groups. EIMD decreases maximal voluntary contraction (MVC), restricts the range of motion (ROM), and increases muscle stiffness and delayed-onset muscle soreness, all of which negatively impact athletic performance. Therefore, developing effective recovery strategies is essential. Methods: A double-blind, randomized, placebo-controlled trial was conducted with 40 healthy male and female participants. After 33 days of supplementation with either CrM or placebo (crystalline cellulose), the participants performed eccentric exercises. Recovery indices, including MVC, muscle stiffness, subjective muscle extensive soreness, fatigue, and upper arm circumference, were measured at baseline, immediately after exercise, 48 h post-exercise, and 96 h post-exercise. Results: The creatine supplementation group (CRE) demonstrated a significantly quicker recovery of MVC than the placebo group (PLA). Furthermore, reductions in shear modulus and muscle fatigue were observed in the CRE group. Notably, females in the CRE group exhibited a significant suppression of post-exercise edema, suggesting a sex-specific response. Conclusions: These findings indicate that CrM supplementation may enhance recovery from EIMD, contributing to the maintenance of muscle function and the reduction of discomfort after exercise. CrM has the potential to serve as a practical nutritional strategy to promote recovery, not only for athletes, but also for a broader population.

A noninvasive, immediate, and convenient method for assessing muscle tissue status during exercise-induced muscle damage (EIMD) has not been established. This study was designed to assess and determine parameters suitable for measuring EIMD after eccentric exercise, using multi-frequency bioimpedance analysis (BIA). Thirty-five young male participants performed dumbbell exercises with their left arm, and their BIA parameters were measured at various time points up to 168 h post exercise using a multi-frequency BIA device. At all-time points, intra and extracellular water content was greater in the left arm than in the right arm, whereas the impedance, reactance, resistance, and phase angle were lower in the left arm than in the right arm. Established EIMD indices, such as maximal isometric voluntary contraction, were measured and used in correlational analyses. Only reactance was correlated with biomarkers, indicating muscle damage (r = − 0.56 to − 0.49). Furthermore, reactance was found to correlate well with indirect indicators of EIMD, suggesting that it may be a suitable marker for evaluating EIMD. However, the relationship with the limited evaluation indices employed in this study is constrained. Future studies should investigate the correlation between reactance and direct damage indicators, such as structural damage, observed in biopsies.

交代浴（CWT）が中程度の高度でのトレーニングによる脱水症状を軽減しパフォーマンスを向上させるという仮説を検証した。その結果、CWT グループの4,5日目の脱水症状を示す 細胞外水/体内総水分値が有意に低かった。しかしグループ間で 反応性強度指数に有意な差なかった。CWT はトレーニングキャンプの初期段階での脱水症状を軽減するが、パフォーマンスには影響しない可能性がある。

マッサージの圧力が筋肉硬さの軽減に関連するか検討した。10 分間の上腕と下腿をマッサージにより、せん断弾性率はPost,5分後に減少し、両方の筋の総マッサージ圧力とせん断弾性率の変化率の間に負の相関関係があった。

Despite the known beneficial effects of creatine in treating exercise-induced muscle damage (EIMD), its effectiveness remains unclear. This study investigates the recovery effect of creatine monohydrate (CrM) on EIMD. Twenty healthy men (21–36 years) were subjected to stratified, randomized, double-blind assignments. The creatine (CRE) and placebo (PLA) groups ingested creatine and crystalline cellulose, respectively, for 28 days. They subsequently performed dumbbell exercises while emphasizing eccentric contraction of the elbow flexors. The EIMD was evaluated before and after exercise. The range of motion was significantly higher in the CRE group than in the PLA group 24 h (h) post exercise. A similar difference was detected in maximum voluntary contraction at 0, 48, 96, and 168 h post exercise (p = 0.017–0.047). The upper arm circumference was significantly lower in the CRE group than in the PLA group at 48, 72, 96, and 168 h post exercise (p = 0.002–0.030). Similar variation was observed in the shear modulus of the biceps brachii muscle at 96 and 168 h post exercise (p = 0.003–0.021) and in muscle fatigue at 0 and 168 h post exercise (p = 0.012–0.032). These findings demonstrate CrM-mediated accelerated recovery from EIMD, suggesting that CrM is an effective supplement for EIMD recovery.

本稿では，21世紀型市民の育成として学士力の保証が求められている高等教育の現状を踏まえつつ，体育教育の目的の再確認，大学体育授業における目的と目標の整理，さらにその目標に準拠した評価の在り方について述べた．

クレアチン摂取群 (CRE)とプラセボ群(PLA) 群で運動誘発性筋損傷(EIMD)に対する回復効果を調査した。肘屈筋のEIMD誘発運動に対し、24 時間後の可動域、直後 0,48,96,168 時間後のMVCと上腕周囲径、96,168 時間後のせん断弾性率は CRE群が PLA群よりも有意に低かった。これらの発見は、クレアチンを介して EIMD からの回復が促進されることを示している。

大学体育実技の成績評価の観点と方法に関してアンケート調査を実施した．成績評価の観点は技術や技能，知識や理解，態度や意欲，出席の 4 つに分類できた。成績評価方法に関してコロナ禍に新たな対応を行ったのは54校であった．本研究は，近年における大学体育実技の成績評価方法の実態を明らかにし，また遠隔授業の導入による成績評価方法の新たな対応について情報を得た点で，大学教育改革を進める上での資料的価値が高いと考えられる．

Changes in biceps brachii muscle hardness assessed by a push-in meter (PM) and strain elastography (SE) were compared between eccentric (ECC) and concentric contractions (CON) of the elbow flexors to test the hypothesis that muscle hardness would increase greater after ECC. Ten men performed 5 sets of 10 ECC with their non-dominant arms and 5 sets of 10 CON with their dominant arms using a dumbbell corresponding to 50% of maximum voluntary isometric contraction (MVIC) force at 90º elbow flexion. Before and 1–4 days after the exercise, MVIC force, elbow joint angles, upper-arm circumference, and muscle soreness as muscle damage makers, and biceps brachii muscle hardness at maximally extended elbow joint by PM and SE were measured. Changes in these measures over time were compared between ECC and CON. All muscle damage markers showed greater changes after ECC than CON (p < 0.001). Muscle hardness assessed by PM and SE increased (p < 0.05) and peaked at 4 days post-ECC with 154.4 ± 90.0% (PM) and 156.2 ± 64.2% (SE) increases from the baseline, but did not change significantly after CON. The changes in muscle hardness post-ECC were correlated between PM and SE (r = 0.752, p < 0.001). A correlation (p < 0.001) between the normalized changes in resting elbow joint angle and changes in muscle hardness assessed by PM (r = − 0.772) or SE (r = − 0.745) was also found. These results supported the hypothesis and suggest that the increases in muscle hardness after ECC were associated with muscle damage (increased muscle stiffness), and PM and SE detected muscle hardness changes similarly.

This study aimed to investigate the relationship between the muscle shear modulus of the biceps brachii, urinary titin N-terminal fragment (UTF), and other damage markers after eccentric exer-cise. Seventeen healthy males performed five sets of ten eccentric exercises with dumbbells weighing 50% of the maximum voluntary contraction (MVC) at the elbow joint. Muscle shear modulus with range of interest set to only biceps brachii muscle measured by ultrasound shear wave elastography, UTF, MVC, range of motion (ROM), and soreness (SOR) were recorded before, immedi-ately after, and 1, 24, 48, 72, 96, and 168 h after eccentric exer-cise. Each marker changed in a time course pattern, as found in previous studies. The peak shear modulus showed a moderate negative correlation with peak MVC (r = –0.531, P < 0.05) and a strong positive correlation with peak UTF (r = 0.707, P < 0.01). Our study results revealed a significant relationship between muscle strength, shear modulus measured by ultrasound SWE, and titin measured by UTF, as a non-invasive damage marker after eccentric exercise to track changes in EIMD.

健康増進センター利用者の血液生化学検査結果に与える運動の影響を知るため対照実験を実施した。その結果運動による血液成分の差異が認められ、特に血清脂質の差から運動の成人病予防効果が示された。