Published papers

OBJECTIVES: This study aimed to clarify the kinematic, kinetic characteristics associated with lateral ankle sprain. DESIGN: A 16-month prospective cohort study. SETTING: Laboratory. PARTICIPANTS: A total of 179 college athletes. MAIN OUTCOME MEASURES: Joint kinematics, moment during single-leg landing tasks, and ankle laxity were measured. The attendance of each participating team, injury mechanism, existence of body contact, presence of orthosis, with or without medical diagnosis, and periods of absence were recorded. RESULTS: Twenty-nine participants incurred lateral ankle sprain during non-contact motion. The Cox regression analysis revealed that greater knee varus peak angle (hazard ratio: 1.16 [95% confidence interval: 1.10-1.22], p < 0.001) and greater pelvic internal rotation peak angle toward the support leg were associated with lateral ankle sprain (hazard ratio: 1.08 [95% confidence interval: 1.02-1.15], p = 0.009). The cut-off values for each predictive factor were -0.17° (area under the curve = 0.89, p < 0.001) and 6.63° (area under the curve = 0.74, p < 0.001), respectively. CONCLUSIONS: A greater knee varus peak angle and pelvic internal rotation peak angle after single-leg landing are predictive factors for lateral ankle sprain.

Long-distance running results in lowering of the foot medial longitudinal arch, but it is unknown whether the left and right arches decrease equally. This study aimed to determine whether foot arch asymmetry increases upon completion of a full marathon and to identify factors capable of explaining the degree of asymmetry of navicular height and navicular height displacement. The three-dimensional foot posture data of 74 collegiate runners were obtained using an optical foot scanner system before (PRE) and immediately after (POST) a full marathon. The navicular height and arch height ratio (normalised navicular height by foot length) of both feet significantly decreased from PRE to POST full marathon completion (44.3 ± 6.3 mm versus 40.8 ± 6.5 mm, 17.8 ± 2.5 versus 16.6 ± 2.7, respectively; p < 0.001, both). The asymmetry of the arch height ratio was significantly greater POST than PRE marathon. Multiple linear regression analysis indicated that the POST-race Asymmetry Index (AI) of navicular height was significantly predicted by the PRE-race AI of navicular height; navicular height displacement was predicted by PRE-race navicular height and the marathon time. Full marathon running induced increasing asymmetry and lowering of the medial longitudinal arch in runners.

Purpose To investigate the effects of full marathon running on intrinsic and extrinsic foot muscle damage and to determine the relationship with the height change of the longitudinal foot arch following full marathon completion. Methods Magnetic resonance imaging‐measured transverse relaxation time (T2) of the abductor hallucis (ABH), flexor digitorum brevis (FDB) and quadratus plantae (QP), flexor digitorum longus (FDL), tibialis posterior (TP), and flexor hallucis longus (FHL) from 22 collegiate runners were assessed before and 1, 3, and 8 days after full marathon running. The three‐dimensional foot posture of 10 of the 22 runners was further obtained using a foot scanner system before and 1, 3, and 8 days after the marathon. Results Marathon‐induced increases in T2 were observed in the QP, FDL, TP, and FHL 1 day after the marathon (+7.5%, +4.7%, +6.7%, and +5.9%, respectively), with the increased T2 of TP persisting until 3 days after the marathon (+4.6%). T2 changes of FDL and FHL from pre‐marathon to DAY 1 showed direct correlations with the corresponding change in the arch height ratio (r = 0.823, p = 0.003, and r = 0.658, p = 0.038). Conclusion The damage and recovery response from a full marathon differed among muscles; QP, FDL, TP, and FHL increased T2 after the marathon, whereas ABH and FDB did not. In addition, T2 changes in FDL and FHL and the arch height ratio change were correlated. Our results suggest that the extrinsic foot muscles could be more susceptible to damage than the intrinsic during marathon running.

© 2016 The Author(s). Measurements using an accelerometer reflect the impact applied to the trunk. Measurement of trunk acceleration has the possibility of reflecting the typical characteristics of trunk motion during cutting. However, analysis of trunk acceleration data during cutting manoeuvres has not been previously conducted. This study aimed to analyse trunk acceleration during cutting manoeuvres to examine any gender differences or a relationship with posture. All participants (eight male and eight female college soccer athletes) performed a shuttle run cutting task, and trunk accelerations (medio-lateral, vertical, and antero-posterior) were calculated. The peak acceleration (G) and total magnitude during the 200 ms after foot contact were measured, and the forward trunk inclination and femoral angle were calculated from the video images taken using a sagittal plane camera. Peak vertical acceleration (mean, s) was significantly greater among female athletes than among male athletes (-2.18, s = 0.84 G; -1.15, s = 0.45 G, respectively; p < 0.01). Medio-lateral and anteroposterior peak acceleration and the total magnitude in all directions were not significantly different between genders. Moderate negative correlations were found between vertical peak acceleration and trunk forward inclination and femoral inclination (r = -0.57, p < 0.05; r = -0.69, p < 0.01, respectively). The difference in vertical acceleration between genders has the possibility to reflect a stiff cutting movement among female athletes. The acceleration of the upper trunk may be an index for evaluating cutting movements.

The aim of the present study was to qualitatively analyze the implementation of rubric-based performance assessment within university practical physical education, highlighting its advantages and challenges. In higher education, the need for visible learning outcomes has drawn attention to rubrics as a tool for ensuring transparency and consistency in performance assessment. In particular, the grading of practical physical education has often been subject to individual teacher discretion, raising concerns over the lack of clarity in assessment criteria. On the other hand, rubrics are considered effective for ensuring the quality of learning outcomes by offering a multifaceted assessment of student performance and achievements. This study employed the CIPP model (Context, Input, Process, Product) as a theoretical framework to analyze the responses of both students and teachers to the introduction of rubrics in practical physical education classes. Semi-structured interviews with the authors and focus group interviews with students were conducted at one university, focusing on 3 different forms of practical physical education, and the data were analyzed using reflexive thematic analysis. The findings indicated that rubrics had a key advantage of clarifying grading criteria, enabling students to understand the course objectives better and offering them more opportunities to improve their learning outcomes through selfassessment. Additionally, rubrics served as an effective tool for teachers, allowing them to adjust their teaching in line with the evaluation criteria and provide structured feedback to students. On the other hand, challenges were identified, such as the abstract nature of some of the rubric criteria, which made them difficult for certain students to understand. In particular, assessment of skills such as followership and collaboration was considered complex. Furthermore, instructors reported that they had limited time to offer sufficient feedback during the course, leading to a lack of mutual understanding of the assessment criteria between teachers and students. The present study findings are significant in demonstrating that rubric-based performance assessment can promote active learning and enhance fairness and transparency in the grading process of practical physical education. Future challenges include the need to establish a more robust feedback system to ensure that both instructors and students fully understand and effectively utilize the rubric criteria. Additionally, it is important to create a flexible rubric framework that accommodates diverse learning styles and encourages creativity in student performance.

画像解析技術の進歩にともなって、骨格筋3特性のひとつ、質的特性に関する研究が盛んに行われている。超音波エラストグラフィを用いた当該研究領域では、原理原則の異なるいくつかのエラストグラフィ手法が用いられているものの、従来の体表面から押圧した評価法や関節運動をともなった測定法とは一線を画し、画像から生体軟部組織硬度の位置情報を取得できる点に最大の特徴がある。筋の硬さを個別に評価できる利点は、特定の筋のみに焦点を絞った経時変化の観察が可能になることを示しており、特異的なリカバリー手法を提供する起点となっている。本編では、超音波エラストグラフィを用いて評価される筋の質的特性の概略と、硬化した筋に対する戦略的なリカバリー方策(経口補水液と特殊シューズ)の知見に関して報告する。(著者抄録)

© Springer Japan 2015. In this chapter, we evaluate the functional characteristics of the hamstring muscles during sprinting. During near maximal sprinting speed, the respective hamstring muscles exhibited very different characteristics of electromyographic (EMG) activation within the sprinting gait cycle. The activation demand of the BFlh muscles is high before and after foot contact due to their function as hip extensors, while the ST muscle shows high activation primarily during the control of knee extension and hip flexion in the mid-swing phase. The mechanism underlying these activation characteristics may involve architectural differences between the hamstring muscles, which likely reflect each muscle’s function during sprinting. A complex neuromuscular coordination pattern of the hamstring muscles during sprinting is accomplished by the utilisation and activation of each muscle’s specific functional differences.

Inami, T, Nakagawa, K, Yonezu, T, Fukano, M, Higashihara, A, Iizuka, S, Abe, T, and Narita, T. Tracking of time-dependent changes in muscle hardness after a full marathon. J Strength Cond Res 33(12): 3431-3437, 2019-We sought to identify changes in individual muscle hardness after a full marathon and to track time-dependent changes using ultrasound strain elastography (SE). Twenty-one collegiate marathon runners were recruited. Muscle hardness (i.e., strain ratio, SR) was measured using SE for the rectus femoris (RF), vastus lateralis (VL), biceps femoris (BF) long head, tibialis anterior (TA), gastrocnemius medial (GM) head, and soleus (SOL) muscles at the following time points: pre (PRE), immediately post (POST), day-1 (D1), day-3 (D3), and day-8 (D8), after a full marathon. We found that the SR decreased after the full marathon (i.e., the muscle became harder), and that the lowest SR across all measured muscles was observed on D1. Although there was no difference in the magnitude of change in SR between the muscles of the thigh, that of the MG and SOL were significantly larger than that of the TA. Muscle hardness in the vastus lateralis, biceps femoris, and SOL recovered at D8 (i.e., nonsignificant difference from PRE), whereas recovery of rectus femoris and gastrocnemius medial hardness at D8 was not observed. Thus, the degree of change in muscle hardness does not occur uniformly within the lower extremity muscles. In particular, changes in muscle hardness of the TA after a full marathon are small compared with other muscles and time-dependent changes in each muscle vary during recovery. The features of muscle hardness identified in this study will be useful for coaches when mentoring runners on proper forms and for training advisers and therapists who seek to address deficiencies in running.

【はじめに，目的】　本研究ではフルマラソンを例に，身体衝撃を反映する体幹加速度を経時的に計測し，長時間のスポーツ活動における身体衝撃の変化を明らかにすることを目的とした。【方法】　健常成人男性4名を対象とした。フルマラソン走行時に体幹背面上部にGPS付き加速度センサを装着し，3軸加速度をスタートからゴールまで計測した。その内，カーブがなく平坦な7.5km，17.5km，27km，36km地点をGPSデータより特定し，各地点における100歩を解析対象とした。加速度データより1歩毎の最大合成加速度（G），および走行スピード（km/h）を算出した。地点間の加速度の差を，走行スピードを共変量とした共分散分析を用いて検討した。【倫理的配慮】　日本女子体育大学研究倫理委員会の承認を得た後，対象者から文章にて説明し同意を得て実施した。【結果】　地点毎の加速度は7.5km：4.2（0.6）G，17.5km：3.9（0.6）G，27km：3.7（0.5）G，36km：4.1（0.8）G［平均値（標準偏差）］であった。共分散分析の結果，地点間に有意な主効果が認められ（F（3,1573）=72.037，p＜0.001，偏η2=0.12），体幹加速度は7.5km地点にて17.5kmおよび27km地点より有意に大きく，36km地点にて他3地点より有意に大きかった（いずれもp＜0.001）。【考察】　身体衝撃の指標であるフルマラソン中の体幹加速度はレース中盤で低下した後，終板で再び増加した。この結果は，レース終板における疲労や動作変化に起因する衝撃緩衝能の低下を反映したと考えられる。