Japanese Journal of Athletic Training
Online ISSN : 2433-572X
Print ISSN : 2432-6623
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Showing 1-13 articles out of 13 articles from the selected issue
  • [in Japanese]
    2020 Volume 6 Issue 1 Pages 1
    Published: October 31, 2020
    Released: November 28, 2020
    JOURNALS FREE ACCESS
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  • Takashi FUKUDA
    2020 Volume 6 Issue 1 Pages 3-13
    Published: October 31, 2020
    Released: November 28, 2020
    JOURNALS FREE ACCESS

    A high head and neck injury rate has been one of the problems in American football since the birth of this sport in the late 18th century. The popularity of American football in the united states encouraged research projects to be secured a player. In fact, studies in American football contributed to the rule changes and helmet renovations.

    Originally a helmet became harder to prevent a catastrophic injury. However, a spinal cord injury increased by a spearing tackle in which a player made initial contact with the crown of the helmet as a weapon to an opponent player. The rule change to prohibit the tackle in 1976 resulted in more effective prevention of a serious head and neck injury. It is also clear that medical examination by using a x-ray or a computed tomography is preferred since the Torg ratio less than 0.8 increases the risk of cervical spine injuries.

    Now a concussion is widely recognized as a social problem. Many studies also have been conducted in the united states but for now there is a lack of effective evidence-based prevention. To be cleared, no helmet can prevent it. Additionally, it is not clear that correct tackling techniques and cervical muscle strength are effective to prevent it.

    More concussion studies in Japan are expected in the future because it remains doubtful that all results apply to Japanese athletes of different physiques and physical abilities to American counterparts.

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  • Keita SUZUKI, Satoshi NAGAI, Masahiro TAKEMURA
    2020 Volume 6 Issue 1 Pages 15-23
    Published: October 31, 2020
    Released: November 28, 2020
    JOURNALS FREE ACCESS

    Rugby football players frequently suffer head and neck injuries, and the prevention of these injuries is an important topic for everyone involved into rugby football. Reduction of these injuries can be effectively promoted by clarifying their etiologies and mechanisms. This study aimed to describe the preventive approaches for rugby-related head and neck injuries by reviewing previous studies from the point of view of both an epidemiological survey and video analysis of inciting events.

    After reviewing the epidemiological survey in rugby, we found it is required to increase the number of studies targeting female rugby players and research on neck injuries for youth players. Moreover, we noticed, from the video analysis of inciting events, professional and international players are often targeted. Given the differences in physical and tactical game characteristics at different competition levels, generalizing the professional and international players’ characteristics should be cautiously considered among players at other competition levels. Therefore, further studies are required to analyze the events leading to rugby-related head and neck injuries in various competition levels in Japan. Improvement of individual tackle skills has an effect on reduction in the tackle events that resulted in head and neck injuries. However, effective intervention has not yet been established, and medical staff should be familiar with individual tackle skills. Therefore, they should understand the technical characteristics that influence the occurrence of rugby-related head and neck injuries and collaborate with the coaching staff so that players can play safely and effectively.

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  • Sentaro KOSHIDA
    2020 Volume 6 Issue 1 Pages 25-32
    Published: October 31, 2020
    Released: November 28, 2020
    JOURNALS FREE ACCESS

    This review article’s objective was to report on the epidemiology of judo-related head and neck injuries, identify the risk factors and injury mechanism, explore the current prevention strategies, and address the direction of future research. Epidemiologic studies have reported that non-negligible numbers of severe head and neck injuries have been sustained from judo in Japanese school settings. However, the epidemiology of relatively minor injuries such as head concussions is still unknown. Judo-related head injuries often occur when young judo beginners are thrown backward with osoto-gari. In contrast, neck injuries more frequently occur when experienced judokas fall forward from the head in both offensive and defensive situations. Analysis of injury statistics suggests that coach education is the most effective strategy in decreasing judo-related head injuries. It has also proposed that breakfall skill improvement, neck strengthening, and rule/regulation changes may reduce the risk of head and neck injuries in judokas. However, the research evidence for these strategies preventing head and neck injuries remains limited. Future studies will need to investigate the epidemiology of judo-related head and neck injuries using a standardized format. The author also recommends developing effective breakfall coaching programs for better preventing the injuries from occurring in novice judokas.

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  • Chika NAKAJIMA, Masahiro YOSHIDA, Ryo ISHIKAWA, Yoichi KOMIYAMA, Keizo ...
    2020 Volume 6 Issue 1 Pages 33-41
    Published: October 31, 2020
    Released: November 28, 2020
    JOURNALS FREE ACCESS

    The purpose of this study was to investigate the effects of fatigue on side hop test results and ankle biomechanics for chronic ankle instability (CAI). We assessed 10 collegiate athletes with CAI. Side hop test was performed before and after a fatigue-inducing exercise. We measured 3-D ankle kinematics, kinetics, and surface electromyography during the side hop test. The side hop time was significantly greater after the fatigue exercise (8.55±0.74 seconds) than before (8.06±0.69 seconds). Fatigue decreased plantar flexion moment and tibialis anterior muscle activity as well as increased inversion moment and internal rotation angle.

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  • Ryo ISHIKAWA, Masahiro YOSHIDA, Chika NAKAJIMA, Keizo YAMAMOTO, Makoto ...
    2020 Volume 6 Issue 1 Pages 43-48
    Published: October 31, 2020
    Released: November 28, 2020
    JOURNALS FREE ACCESS

    The purpose of this study was to identify characteristic of COP sway and EMG during toe balance test (TBT) for athletes with chronic ankle instability(CAI). The study subjects included athletes with CAI and 12 healthy athletes. In all the subjects, the center of pressure (COP) and the ankle inversion/eversion and dorsal/planter flexion angles, and the electromyography (EMG) activities of the tibialis anterior (TA) and peroneus longus (PL), lateral gastrocnemius (LG), medial gastrocnemius (MG) were measured during the single-leg balance (SLB) and TBT. The COP pathlength during the TBT was greater than that during the SLB test (p < 0.05). The COP pathlength during the TBT was not significantly different between the healthy and CAI groups (p > 0.05). The EMG activities of the TA (p < 0.01) and MG (p < 0.01), PL (p < 0.05) were greater in the CAI group than in the healthy group. We suggest that the TBT is a more difficult test than the SLB test and that CAI controlled posture using muscle activities different from those in the healthy group.

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  • Yui SHIMADA, Shogo SASAKI
    2020 Volume 6 Issue 1 Pages 49-57
    Published: October 31, 2020
    Released: November 28, 2020
    JOURNALS FREE ACCESS

    We aimed to compare the modified Tuck Jump Assessment (TJA) and a tri-axial accelerometer for evaluation of the efficacy of a prevention program for anterior cruciate ligament injury. Twenty-two female high school basketball players participated and were divided into two groups: an intervention group (n=10) and control group (n=12). The intervention group underwent an injury prevention program for 17 weeks, whereas the control group maintained a regular training routine. Each participant conducted a tuck jump test in 10 seconds while wearing a tri-axial accelerometer on their upper back. The TJA score and vertical trunk acceleration during tuck jump landing were analyzed before and after the training period. The total TJA score did not change significantly in both the intervention and control groups. Vertical trunk acceleration decreased in the intervention group (pre-test: 8.2±1.6 G, post-test: 6.7±1.0 G, p<0.001), whereas it did not change in the control group (pre-test: 7.6±2.0 G, post-test: 7.5±1.7 G, p=0.842). This short-term longitudinal study suggests that injury prevention training for junior basketball players may change their landing mechanics during a tuck jump test. Furthermore, combining TJA and a wearable sensor such as an accelerometer device may be useful to evaluate training efficacy more objectively.

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  • Fumiaki ONISHI, Yuji IIDA, Ichiro WATANABE, Hiromu SATO, Norikazu HIRO ...
    2020 Volume 6 Issue 1 Pages 59-65
    Published: October 31, 2020
    Released: November 28, 2020
    JOURNALS FREE ACCESS

    Walking speed helps predict longevity. Several exercises, especially for elderly people, aim at improving walking ability; nevertheless, there are only a few reports of body-weight exercise programs. People who exercise utilize their body as load, and various factors may affect the results. Body composition is one of these factors that is easy to measure at home. The purpose of this study was to determine the effect of a body-weight exercise program on walking speed in the elderly and the contribution of physical characteristics. Twenty people aged >65 years were divided into two groups (control and exercise). In one subject, the post-intervention measurement could not be scheduled at the same measurement day as for the other subjects; therefore, his data were excluded. The exercise group participated in a 6-week training program composed of body-weight exercises focusing on the lower extremity in a 10.5-week experiment period. The maximum-walking speed (MWS) was compared before and after the intervention. Multi-regression analysis was performed to determine the relationship between % change in MWS and % change in factors such as age, body weight, percent-body fat (% BF), upper-body skeletal muscle index (UBSMI), lower-body skeletal muscle index (LBSMI), and broad jump (BJ). The results showed a significant decrease in MWS in the control group but no significant change was found in the exercise group. There was a significant relationship between % change in MWS and % change in %BF in the exercise group and between % change in MWS and % change in age, %BF, UBSMI, LBSMI, and BJ in the control group. These results suggest that the body-weight training program was effective at preventing reduction in MWS and that the changes in physical characteristics may affect the change in MWS in the elderly.

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  • Atsuya KOIDE, Yuri HOSOKAWA
    2020 Volume 6 Issue 1 Pages 67-73
    Published: October 31, 2020
    Released: November 28, 2020
    JOURNALS FREE ACCESS

    We aimed to report a case study of exertional heat stroke prevention strategies imple-mented by full-time athletic trainer in a Japanese high school. Exertional heat stroke prevention strategies included: (1) modifications in practice time, (2) activity modification guidelines based on environmental condition, (3) proper hydration, (4) optimizing available equipment and practice environment, and (5) education. These prevention strategies involved various stakeholders of school (e.g., administrator, school nurse, faculty, coach) for implementation. Future effort to quantify effects from these strategies are warranted to establish exertional heat stroke prevention program that can be applied in other schools.

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  • Shogo SASAKI, Shoichiro IMAMURA, Yusaku SUGANUMA, Yasuharu NAGANO
    2020 Volume 6 Issue 1 Pages 75-86
    Published: October 31, 2020
    Released: November 28, 2020
    JOURNALS FREE ACCESS

    This study presents a single-legged functional ability and subjective performance toward return-to-play (RTP) to soccer competitions after anterior cruciate ligament reconstruction. A male collegiate soccer player was assessed using the following battery of single-legged tests: single, triple, and crossover hop for distance; side hop, up-down, and figure-of-eight hop for speed; vertical single-limb hop for lower limb power; and vertical ground reaction force and center of mass pressure (COP) trajectory during forward and lateral drop landing tasks for dynamic balance. The limb symmetry index (LSI) was expressed as a ratio of the injured limb to the uninjured limb. Lower limb asymmetry appeared in single-legged hop for distance and speed tests in a prior stage of RTP. After returning to play at a low performance level, a functional deficit was shown in the single hop for distance, figure-of-eight hop for speed, and COP trajectory during lateral drop landing. In the improvement stage of subjective performance, the LSI of figure-of-eight hop was over 100 and a smooth change-of-direction maneuver with body inclination was observed in the figure-of-eight hop test. This practical study may contribute to successful return-to-play, not only in terms of safety and early return-to-play, but also performance enhancement.

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  • Nobuko SHIMIZU, Toshiharu YAMAMOTO, Masashi KASAHARA
    2020 Volume 6 Issue 1 Pages 87-94
    Published: October 31, 2020
    Released: November 28, 2020
    JOURNALS FREE ACCESS

    The aim of this study was to introduce the drafting and use of emergency action plans (EAPs) that we have been implementing in sports in order to carry out emergency response procedures, and to clarify the need for the involvement of athletic trainers (ATs) in the drafting, use, and promotion of EAPs in sports. In the preparation of a safer emergency system for sports, ATs who can carry out emergency response procedures play a primary role in creating EAPs. Using their past examples may offer benefits above simply drafting EAPs by also helping to raise awareness of the importance of the use and spread of EAPs.

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