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1.
Keitaro Kubo Daisuke Miyazaki Shigeharu Tanaka Shozo Shimoju Naoya Tsunoda 《Journal of sports sciences》2015,33(7):665-669
The purpose of this study was to investigate the relationship between Achilles tendon properties and foot strike patterns in long-distance runners. Forty-one highly trained male long-distance runners participated in this study. Elongation of the Achilles tendon and aponeurosis of the medial gastrocnemius muscle were measured using ultrasonography, while the participants performed ramp isometric plantar flexion up to the voluntary maximum. The relationship between the estimated muscle force and tendon elongation during the ascending phase was fit to a linear regression, the slope of which was defined as stiffness. In addition, the cross-sectional area of the Achilles tendon was measured using ultrasonography. Foot strike patterns (forefoot, midfoot and rearfoot) during running were determined at submaximal velocity (18 km · h?1) on a treadmill. The number of each foot strike runner was 12 for the forefoot (29.3%), 12 for the midfoot (29.3%) and 17 for the rearfoot (41.5%). No significant differences were observed in the variables measured for the Achilles tendon among the three groups. These results suggested that the foot strike pattern during running did not affect the morphological or mechanical properties of the Achilles tendon in long-distance runners. 相似文献
2.
Perception of affordances research in children with developmental disabilities has only examined well practiced skills. Ten toddlers with Down syndrome and 10 with typical development walked across a GAITRite mat, with and without an obstacle. We coded the toddlers' behaviors after 1 and 3 months of walking experience when they encountered the obstacle (avoid, crawl, error and walk successfully) and calculated gait parameters (step length, width, and velocity). Both groups actively explored their affordances. Despite similar decreases in step length and velocity when approaching the obstacle, toddlers with Down syndrome were more likely to select successful but conservative crawling strategies that minimized balance requirements and reduced risk of falling. Group differences were due to risk management rather than difficulty perceiving affordances. 相似文献
3.
The aim of the present study was to examine the effects of viscoelastic properties of human tendon structures during stretch?–?shortening cycle exercise. The elongation of tendon and aponeurosis of the medial gastrocnemius muscle of 26 participants was measured by ultrasonography while they performed ramp isometric plantar flexion up to the voluntary maximum, followed by a ramp relaxation. The relationship between estimated muscle force and tendon elongation during the ascending phase was fitted to a linear regression, the slope of which was defined as stiffness. The percentage of the area within the muscle force?–?tendon elongation loop relative to the area beneath the curve during the ascending phase was defined as hysteresis. In addition, maximal voluntary concentric contractions at 2.09 and 3.14 rad?·?s?1 with and without prior eccentric contractions were performed. The difference in the concentric torque at equivalent joint angles with and without prior eccentric contractions (i.e. pre-stretch augmentation) was negatively correlated with stiffness (P <?0.05) and hysteresis (P <?0.05). Furthermore, there was a higher correlation between the pre-stretch augmentation and the viscoelastic properties index – that is, the sum of normalized score values of stiffness and hysteresis (P <?0.01) – than with either stiffness or hysteresis alone. The results of this study suggest that performance during stretch?–?shortening cycle exercise is significantly affected by the viscoelastic properties of the tendon structures. 相似文献
4.
We investigated the effects of two types of nonweight-bearing exercise on changes in bone-specific alkaline phosphatase (BAP) and procollagen type 1 C-peptide (PIP). BAP is a specific marker of bone synthesis, whereas P1P reflects synthesis of type 1 collagen in other organs as well as bone. Eight participants performed static and dynamic unilateral knee extensions. BAP and PIP were measured before, and at 1, 2, 24, 48, and 72 hr after exercise. PIP increased at 24 hr after a static knee extension exercise, whereas BAP did not change during the experimental period. We found no changes in these markers after dynamic exercise. These results imply that type I collagen synthesis in tendons increases after static exercise. 相似文献
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The aim of the present study was to examine the effects of viscoelastic properties of human tendon structures during stretch - shortening cycle exercise. The elongation of tendon and aponeurosis of the medial gastrocnemius muscle of 26 participants was measured by ultrasonography while they performed ramp isometric plantar flexion up to the voluntary maximum, followed by a ramp relaxation. The relationship between estimated muscle force and tendon elongation during the ascending phase was fitted to a linear regression, the slope of which was defined as stiffness. The percentage of the area within the muscle force-tendon elongation loop relative to the area beneath the curve during the ascending phase was defined as hysteresis. In addition, maximal voluntary concentric contractions at 2.09 and 3.14 rad x s(-1) with and without prior eccentric contractions were performed. The difference in the concentric torque at equivalent joint angles with and without prior eccentric contractions (i.e. pre-stretch augmentation) was negatively correlated with stiffness (P < 0.05) and hysteresis (P < 0.05). Furthermore, there was a higher correlation between the pre-stretch augmentation and the viscoelastic properties index--that is, the sum of normalized score values of stiffness and hysteresis (P < 0.01)--than with either stiffness or hysteresis alone. The results of this study suggest that performance during stretch-shortening cycle exercise is significantly affected by the viscoelastic properties of the tendon structures. 相似文献
7.
Tomoya Takabayashi Mutsuaki Edama Masatoshi Nakamura Emi Nakamura Takuma Inai Masayoshi Kubo 《European Journal of Sport Science》2017,17(10):1289-1296
Females, as compared with males, have a higher proportion of injuries in the foot region. However, the reason for this gender difference regarding foot injuries remains unclear. This study aimed to investigate gender differences associated with rearfoot, midfoot, and forefoot kinematics during running. Twelve healthy males and 12 females ran on a treadmill. The running speed was set to speed which changes from walking to running. Three-dimensional kinematics of rearfoot, midfoot, and forefoot were collected and compared between males and females. Furthermore, spatiotemporal parameters (speed, cadence, and step length) were measured. In the rearfoot angle, females showed a significantly greater peak value of plantarflexion and range of motion in the sagittal plane as compared with males (effect size (ES)?=?1.55 and ES?=?1.12, respectively). In the midfoot angle, females showed a significantly greater peak value of dorsiflexion and range of motion in the sagittal plane as compared with males (ES?=?1.49 and ES?=?1.71, respectively). The forefoot peak angles and ranges of motion were not significantly different between the genders in all three planes. A previous study suggested that a gender-related difference in excessive motions of the lower extremities during running has been suggested as a contributing factor to running injuries. Therefore, the present investigation may provide insight into the reason for the high incidence of foot injuries in females. 相似文献
8.
Kubo K Ohgo K Takeishi R Yoshinaga K Tsunoda N Kanehisa H Fukunaga T 《Research quarterly for exercise and sport》2006,77(4):408-416
The purpose of this study was to investigate the effects of series elasticity on the torque-angle relationship of the knee extensors in vivo. Forty-two men volunteered to take part in the present study. The participants performed maximal voluntary isometric contractions at eight knee-joint angles (40, 50, 60, 70, 80, 90, 100, 110 degrees). The elongation of the tendon and aponeurosis of the vastus lateralis muscle was directly measured by ultrasonography, while the participants performed ramp isometric knee extensions to the voluntary maximum at 800 of knee angle. There was no significant difference in the torque value between 50 degrees and 100 degrees, although there was variation in the shape of the "torque-angle" relationship. The variability in the torque-angle curve was not affected by the activation level of agonist and antagonist muscles and the moment arm length. The ratio of torque at 1000 compared to that at 50 degrees was significantly (r(2) = 18-23 %) correlated to the maximal elongation and strain (to initial length) of the tendon structures. These results suggest that increased compliance of tendon structures of the knee extensors may contribute to variations in the torque-angle curves of the knee extensors. 相似文献
9.
In spring 2014, the Henry Madden Library at Fresno State implemented an outreach program for incoming international students consisted of a campus orientation presentation, library orientation and tours, information literacy workshops, and international peer-advisor training. Assessment as a result of the program has shown a high level of use of help services among international students, as well as moderately higher use of several services and resources amongst students who attended the library orientation. 相似文献
10.
Keitaro Kubo Daisuke Miyazaki Toshihiro Ikebukuro Hideaki Yata Masaji Okada Naoya Tsunoda 《Journal of sports sciences》2017,35(8):742-748
The aim of the present study was to investigate and compare muscle and tendon stiffness under active conditions in sprinters and untrained participants. In total, 14 sprinters and 24 untrained men participated in this study. Active muscle stiffness in the medial gastrocnemius muscle was calculated based on changes in estimated muscle force and fascicle length during fast stretching after submaximal isometric contractions. Tendon stiffness was determined during isometric plantar flexion using ultrasonography. No significant differences were observed in active muscle stiffness between sprinters and untrained men at any torque levels. Furthermore, no significant difference was noted in tendon stiffness between the two groups. These results suggest that muscle and tendon mechanical properties in the plantar flexors under active conditions are similar in sprinters and untrained participants. 相似文献