Papers - INAMI, Takayuki

Body composition of collegiate kendo players.

Yoshida, Y., Inami, T., Takase, T.

Journal of Sports Medicine and Physical Fitness Accepted for publication 2021

Research paper (scientific journal), Joint Work, Accepted

Increase in foot arch asymmetry after full marathon completion

Fukano M., Nakagawa K., Inami T., Higashihara A., Iizuka S., Narita T., Maemichi T., yoshimura A., Yamaguchi S., Iso S.

Journal of Sports Sciences (Journal of Sports Sciences)  39 ( 21 ) 2468 - 2474 2021

ISSN  02640414

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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.

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Changes in urinary titin N-terminal fragments as a biomarker of exercise-induced muscle damage in the repeated bout effect

Yamaguchi, S., Suzuki, K., Inami, T., Okada, J.

Journal of Science and Medicine in Sport (Elsevier)  Accepted for publication ( 6 ) 536 - 540 2020

Research paper (scientific journal), Joint Work, Accepted,  ISSN  14402440

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© 2019 Sports Medicine Australia Objectives: Muscle damage symptoms induced by unaccustomed eccentric contraction exercise can be reduced by repeating the experience several times. This phenomenon is termed the repeated bout effect. Although traditional biochemical markers require invasive blood sampling, biochemical measurements have recently been developed that can be non-invasively performed using urinary titin N-terminal fragment (UTF). However, it is unclear whether UTF can reflect the repeated bout effect. Therefore, the aim of the present study was to clarify whether UTF decreased with the repeated bout effect. Design: This study compared changes in muscle damage markers between bouts of exercise performed for the first and second time. Methods: Eight young men performed 30 eccentric exercises of the elbow flexor on the first day of the first week (Bout 1). A second bout of eccentric exercises, same as the first, was performed 2 weeks later, (Bout 2). The dependent variables were muscle soreness (SOR), maximal voluntary isometric contraction (MVIC), range of motion (ROM), creatine kinase (CK), and UTF. All dependent variables were analyzed using two-way analysis of variance. Results: No significant difference was observed in workload or peak torque between the first and second exercise bouts. SOR as well as CK and UTF were significantly lower and ROM and MVIC were significantly higher in Bout 2 in comparison to Bout 1. Conclusions: These results suggest that UTF sensitively reflects the repeated bout effect and exercise-induced muscle damage can be non-invasively measured.

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Changes in urinary titan N-terminal fragment concentration after concentric and eccentric exercise

Yamaguchim S., Suzuki, K., Inami, T., Kanda, K., Hanye, Z., Okada, J.

Journal of Sports Science and Medicine 19   121 - 129 2020

Research paper (scientific journal), Joint Work, Accepted

Changes in urinary titin N-terminal fragment concentration after concentric and eccentric exercise

Yamaguchi S., Suzuki K., Inami T., Kanda K., Hanye Z., Okada J.

Journal of Sports Science and Medicine (Journal of Sports Science and Medicine)  19 ( 1 ) 121 - 129 2020

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© Journal of Sports Science and Medicine (2020). We aimed to compare the urinary titin N-terminal fragment (UTF) concentration after concentric and eccentric exercise and to clarify the specific response of UTF to exercise-induced muscle damage (EIMD). Nine healthy young men performed 30 concentric elbow flexion exercises with maximum effort, rested for at least eight weeks, and performed eccentric exercises at the same workload using the same arm. Changes in the maximal voluntary isometric contraction (MVIC), muscle soreness (SOR), range of motion (ROM), serum creatine kinase (CK) activity, and UTF concentrations were recorded before and after for six consecutive days after exercise. There was no significant difference in workload during exercise between the two exercise types. However, serum CK activity increased after eccentric exercise (p < 0.05). Additionally, MVIC, SOR, ROM, and UTF concentration were significantly higher after eccentric exercise than after concentric exercise (p < 0.05). Although workload was the same, the UTF concentration greatly increased after eccentric exercise. Based on these results, we suggest that UTF can be a non-invasive and highly specific biomarker of EIMD.

Regional differences in hamstring muscle damage after a marathon

Higashihara A., Nakagawa K., Inami T., Fukano M., Iizuka S., Maemichi T., Hashizume S., Narita T., Hirose N.

PloS one (PloS one)  15 ( 6 )  2020

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Previous studies suggest that marathon running induces lower extremity muscle damage. This study aimed to examine inter- and intramuscular differences in hamstring muscle damage after a marathon using transverse relaxation time (T2)-weighted magnetic resonance images (MRI). 20 healthy collegiate marathon runners (15 males) were recruited for this study. T2-MRI was performed before (PRE) and at 1 (D1), 3 (D3), and 8 days (D8) after marathon, and the T2 values of each hamstring muscle at the distal, middle, and proximal sites were calculated. Results indicated that no significant intermuscular differences in T2 changes were observed and that, regardless of muscle, the T2 values of the distal and middle sites increased significantly at D1 and D3 and recovered at D8, although those values of the proximal site remained constant. T2 significantly increased at distal and middle sites of the biceps femoris long head on D1 (p = 0.030 and p = 0.004, respectively) and D3 (p = 0.007 and p = 0.041, respectively), distal biceps femoris short head on D1 (p = 0.036), distal semitendinosus on D1 (p = 0.047) and D3 (p = 0.010), middle semitendinosus on D1 (p = 0.005), and distal and middle sites of the semimembranosus on D1 (p = 0.008 and p = 0.040, respectively) and D3 (p = 0.002 and p = 0.018, respectively). These results suggest that the distal and middle sites of the hamstring muscles are more susceptible to damage induced by running a full marathon. Conditioning that focuses on the distal and middle sites of the hamstring muscles may be more useful in improving recovery strategies after prolonged running.

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Biceps brachii muscle hardness assessed by a push-in meter in comparison to ultrasound strain elastography

Murayama, M., Nosaka, K., Inami, T., Shima, N., Yoneda, T.

Scientific Reports (Scientific Reports)  Accepted for publication ( 1 )  2020

Research paper (scientific journal), Joint Work, Accepted

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© 2020, The Author(s). 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.

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Changes in the linear relationship between muscle contraction intensity and muscle hardness after rectus femoris muscle strain

Inami, T., Shimizu, T., Osuga, T., Narita, T., Hirose, N., Murayama, M.

Case Reports in Orthopedics (Hindawi)  7813217   4 2019.11

Research paper (scientific journal), Joint Work, Accepted

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Stretching combined with repetitive small length changes of the plantar flexors enhances their passive extensibility while not compromising strength

Ikeda, N., Inami, T., Kawakami, Y.

J. Sport Sci. Med. (Journal of Sports Science and Medicine)  18 ( 1 ) 58 - 64 2019

Research paper (scientific journal), Joint Work, Accepted

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© Journal of Sports Science and Medicine. Static stretching increases flexibility but can decrease muscle strength; therefore, a method that would avoid the latter has been longed for. In this study, a novel stretching modality was developed that provides repetitive small length changes to the plantar flexor muscles undergoing passive static stretching (minute oscillation stretching). We investigated the effects of minute oscillation stretching on muscle strength and flexibility and its continuance. Isometric plantar flexion strength and maximal ankle joint dorsiflexion angle (dorsiflexion range of motion) were measured in 10 healthy young men (22 ± 2 years) before (pre) and immediately after (post) 3 types of stretching: static stretching, minute oscillation stretching at 15 Hz, and no intervention (control). The dorsiflexion range of motion was also measured at 15, 30, and 60 min post-stretching. Elongation of the medial gastrocnemius and Achilles tendon was determined by ultrasonography. Plantar flexion strength significantly decreased by 4.3 ± 3.5% in static stretching but not in minute oscillation stretching. The dorsiflexion range of motion significantly increased both in static stretching (7.2 ± 8.1%) and minute oscillation stretching (11.2 ± 14.6%), which was accompanied by a significantly larger muscle elongation but not tendon elongation. Elevated dorsiflexion range of motion was maintained until 30 min after minute oscillation stretching, while levels returned to baseline (pre-intervention) 15 min after static stretching. All variables remained unchanged in the control condition. In conclusion, minute oscillation stretching improves extensibility of the muscle belly without decreasing strength. Furthermore, the augmented flexibility to a similar extent to static stretching is retained for 30 min in minute oscillation stretching and within 15 min in static stretching.

Changes in muscle hardness after a full marathon appear different even intramuscularly

Inami, T., Nakagawa, K., Fukano, M., Yonezu, T., Higashihara, A., Iizuka, S., Narita, T., Murayama, M.

J Sports Med Phys Fitness (Minerva Medica)  59 ( 6 ) 1094 - 1096 2019

Research paper (scientific journal), Joint Work, Accepted

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Effects of Self-myofascial Release Using a Foam Roller on Range of Motion and Morphological Changes in Muscle: A Crossover Study

Yoshimura, A., Inami, T., Schleip, R., Mineta, S., Shudo, K., Hirose, N.

J Strength Cond Res (Journal of Strength and Conditioning Research)  35 ( 9 ) 2444 - 2450 2019

Research paper (scientific journal), Joint Work, Accepted,  ISSN  10648011

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Self-myofascial release using a foam roller (FR) is effective in improving range of motion (ROM) in at least some conditions. However, its mechanism is still unclear. Therefore, this study investigated potential acute muscle morphological changes after the FR intervention and aimed to clarify the mechanism of increases in ROM by the FR intervention. We hypothesized that the FR intervention may increase ROM because of changes in fascicle length (FL) and aponeurosis displacement. This crossover study, involving 22 male university students (21.5 6 1.3 years, 170.6 6 4.0 cm, and 64.1 6 8.9 kg; mean 6 SD), compared the FR intervention targeting the gastrocnemius muscle with the control trial. The outcome measures were maximum passive ankle ROM, morphology of the gastrocnemius muscle (FL and aponeurosis displacement) during passive ankle plantar flexor movement, degree of pain during the FR intervention, and sensation of the triceps surae muscle. Although ROM of both dorsiflexion and plantar flexion increased significantly after the FR intervention (p, 0.01), no significant differences were found in FL and aponeurosis displacement before and after the FR intervention. The mean perception of pain during the FR intervention was rated as “slightly uncomfortable,” corresponding to a 2.3 6 2.4-cm on a 9.5-cm visual analog scale. We found that the FR intervention did not influence the morphology of muscle. It is necessary to investigate other factors related to ROM as the next step of this study.

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Changes in autonomic nervous system activity upon pool water entry in middle-aged and elderly men and women assessed by heart rate variability analysis

Nakagaki, A., Inami, T., Baba, R.

Medicine and Biology Accepted for publication 2019

Research paper (scientific journal), Joint Work, Accepted

Optimum displacement of muscle in relation to thickness for biceps brachii hardness measurement using a push-in meter

Murayama, M., Inami, T., Shima, N., Nosaka, K., Uchiyama, T., Yoneda, T.

Biomed. Physical. Eng. Express (Biomedical Physics and Engineering Express)  5 ( 1 ) 017001 2018

Research paper (scientific journal), Joint Work, Accepted

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© 2018 IOP Publishing Ltd. Objective: Muscle hardness measured by a push-in meter is calculated from a force-displacement curve (FDC) based on a two-layer spring model. Since a FDC is not linear, how to set a linear range in the FDC largely affects muscle hardness calculation. The present study investigated the linearity of the FDC to find the best portion relative to muscle thickness (MT) for muscle hardness measurement based on a two-layer spring model. Approach: Forty-seven men (age: 28 ±10 years, height: 176 ±7 cm, body mass: 73 ±11 kg) participated in the present study. Hardness of the biceps brachii muscle was measured at the mid-belly using a push-in meter. The FDC was obtained every 5% up to 50% of the MT, and linear regression equations of ten different portions within the FDC were calculated. The coefficient of determination (R 2 ) of each regression line was compared by ANOVA, and a piecewise linear regression analysis was performed by dividing the identified FDC into three linear segments. Results: One-way ANOVA showed a significant (p < 0.01) main effect in R 2 values of ten regression equations. Post-hoc analyses showed no significant differences in R 2 between 0%-15% MT and 0%-40% MT. While the linearity of the FDC was high between 0%-15% and 0%-40% MT, the highest R 2 value was found at 0%-25% and 0%-30% MT. According to the analysis of three linear segments in the FDC, the mean value of the point between the second and third segments was 28.5 ±4.3% MT. Significance: These results suggested that muscle hardness assessment using a push-in meter should be performed close to 30% MT depth for biceps brachii muscle.

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Unstable rocker shoes promote recovery from marathon-induced muscle damage in novice runners

Nakagawa, K., Inami, T., Yonezu, T., Kenmotsu, Y., Narita, T., Kawakami, Y., Kanosue, K.

Scand. J. Med. Sci. Sports (Scandinavian Journal of Medicine and Science in Sports)  28 ( 2 ) 621 - 629 2018

Research paper (scientific journal), Joint Work, Accepted,  ISSN  09057188

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© 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd We recently reported that wearing unstable rocker shoes (Masai Barefoot Technology: MBT) may enhance recovery from marathon race-induced fatigue. However, this earlier study only utilized a questionnaire. In this study, we evaluated MBT utilizing objective physiological measures of recovery from marathon-induced muscle damages. Twenty-five university student novice runners were divided into two groups. After running a full marathon, one group wore MBT shoes (MBT group), and the control group (CON) wore ordinary shoes daily for 1 week following the race. We measured maximal isometric joint torque, muscle hardness (real time tissue elastography of the strain ratio) in the lower limb muscles before, immediately after, and 1, 3, and 8 days following the marathon. We calculated the magnitude of recovery by observing the difference in each value between the first measurement and the latter measurements. Results showed that isometric torques in knee flexion recovered at the first day after the race in the MBT group while it did not recover even at the eighth day in the CON group. Muscle hardness in the gastrocnemius and vastus lateralis showed enhanced recovery in the MBT group in comparison with the CON group. Also for muscle hardness in the tibialis anterior and biceps femoris, the timing of recovery was delayed in the CON group. In conclusion, wearing MBT shoes enhanced recovery in lower leg and thigh muscles from muscle damage induced by marathon running.

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A case of fetal heart rate deceleration during maternity swimming

中垣明美, 稲見崇孝, 佐々木美果, 馬場礼三

日本臨床スポーツ医学会誌 26 ( 1 ) 144 - 148 2018

Research paper (scientific journal), Joint Work, Accepted

Tracking of time-dependent changes in muscle hardness after a full marathon

Inami, T., Nakagawa, K., Yonezu, T., Fukano, M., Higashihara, A., Iizuka, S., Abe, T., Narita, T.

J. Strength Cond. Res. (Journal of strength and conditioning research)  Accepted for publication ( 12 ) 3431 - 3437 2018

Research paper (scientific journal), Joint Work, Accepted

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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.

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Foot posture alteration and recovery following a full marathon run

Fukano, M., Inami, T., Nakagawa, K., Narita, T., Iso, S.

Eur. J. Sports Sci. (European Journal of Sport Science)  18 ( 10 ) 1338 - 1345 2018

Research paper (scientific journal), Joint Work, Accepted,  ISSN  17461391

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© 2018, © 2018 European College of Sport Science. Prolonged running results in lowering of the foot arch and a low arch is associated with subsequent chronic injuries. Foot posture alteration and recovery following a marathon run remain unknown. Therefore, the present study aimed to evaluate foot posture alteration following a full marathon run. The three-dimensional foot posture data of 11 collegiate runners were obtained using an optical foot scanner system before, and immediately, 1 day, 3 days, and 8 days after a full marathon. The navicular height and arch height ratio significantly decreased from before to immediately, 1 day, 3 days, and 8 days after the marathon (navicular height: before, 44.2 ± 5.0 mm; immediately after, 39.4 ± 5.5 mm; 1 day, 37.7 ± 6.2 mm; 3 days, 38.7 ± 5.5 mm; 8 days, 37.6 ± 5.7 mm; arch height ratio: before, 18.4 ± 1.9; immediately after, 16.5 ± 2.5; 1 day, 15.7 ± 2.5; 3 days, 16.2 ± 2.6; 8 days, 15.6 ± 2.2, P < 0.001, respectively). By contrast, the dorsal height significantly increased from before and immediately after to 1 day after the marathon, and then significantly decreased until 8 days after the marathon (P < 0.001). These results indicate that the recovery patterns of the dorsal and navicular heights following a marathon did not coincide; the dorsal height rose temporally at 1 day after and subsequently decreased, but the navicular height decreased throughout the 8-day period after the marathon. More than one week may be necessary for sufficient foot alignment recovery from marathon-induced changes. .

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The reliability, and discriminative ability of the identification of functional ankle instability questionnaire, Japanese version.

Mineta, S., Inami, T., Fukano, M., Hoshiba, T., Masuda, Y., Yoshimura, A., Kumai, T., Hirose, N.

Phys. Ther. Sport (Physical Therapy in Sport)  Accepted for publication   1 - 6 2018

Research paper (scientific journal), Accepted,  ISSN  1466853X

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© 2018 Elsevier Ltd Objective: To assess the discriminability as well as the reliability, and internal consistency of the Identification of Functional Ankle Instability questionnaire translated into Japanese (IdFAI-J). Design: Cross-sectional study. Setting: Collegiate athletic training/sports medicine clinic. Participants: Twenty bilingual and sixty-five collegiate athletes including participants with and without functional instability (FI). Main outcome measures: The sensitivity, specificity, test retest reliability, and internal consistency of IdFAI-J. Results: The optimal cutoff score between the FI and non-FI participants was >10, with an area under the curve of 0.92. We calculated high sensitivity (0.94) and specificity (0.77) at the cutoff point. For the test-retest reliability, the intraclass correlation coefficient value of the IdFAI-J was 0.96; the standard error of measurement and minimal detectable change value was 1.69 and 3.60, respectively. Cronbach's α was 0.87; there was no improvement when a particular item was deleted from the scale. Conclusions: The IdFAI-J has excellent discriminability, test-retest reliability, and internal consistency. Hence, the IdFAI-J significantly contribute to clinical practice and future research related to ankle instability in Japan.

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High lateral plantar pressure is related to an increased tibialis anterior/fibulalis longus activity ratio in patients with recurrent lateral ankle sprain

Mineta, S., Inami, T., Mariano, R., Hires, N.

Open Access J. Sports Med. 8   123 - 131 2017

Research paper (scientific journal), Joint Work, Accepted

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Anatomical cross-sectional area of the quadriceps femoris and sit-to-stand test score in middle-aged and elderly population: Development of a predictive equation

Saito, A., Ema, R., Inami, T., Maeo, S., Otsuka, S., Higuchi, M., Shibata, S., Kawakami, Y.

J. Physiol. Anthropol. 36   3 2017

Research paper (scientific journal), Joint Work, Accepted

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