Publications by authors named "Kei Akiyama"

Article Synopsis
  • - The study aimed to analyze the electromyography (EMG) activity of the biceps femoris (BF) muscle during the Nordic hamstring exercise (NHE) before and after a critical angle known as the break-point angle (BPA), using data collected through a smartphone app.
  • - Researchers set out to validate the hypothesis that BF EMG activity would peak at the BPA and then gradually decline, measuring activity through specific knee flexion angles during the exercise.
  • - Findings indicated there was no significant difference in EMG activity at BPA compared to peak activity, but BF EMG significantly decreased 20-25° after BPA, emphasizing the need for knee flexion exercises to maintain higher BF EMG at certain angles
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Article Synopsis
  • Sport specialization in young soccer players may increase the risk of overuse injuries, but this risk can vary based on the sport and cultural factors.
  • The study involved 841 male youth soccer players, showing that those who specialized early and trained extensively were more likely to report serious overuse injuries.
  • Results indicate that engaging in multiple sports before age 12 and high training volume during grades five and six are linked to a higher incidence of these injuries.
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Background: A recently developed smartphone application (Nordic Angle) allows the automatic calculation of the break-point angle (BPA) during Nordic hamstring exercise (NHE) without transferring the collected data to a computer. The BPA is the point at which the hamstrings are unable to withstand force. However, the validity of the BPA values obtained by this method has not been examined.

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Suhara, H, Nariai, M, Takagi, T, Akiyama, K, Nagashima, J, and Shiraki, H. Relationship of clubhead speed with explosive power and muscle strength of the hip and trunk joints of elite golfers. J Strength Cond Res 37(4): 859-865, 2023-In golf, the driving distance of the ball is affected by the clubhead speed (CHS) on impact.

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Context: This study aimed to examine the differences in electromyographic (EMG) activity of the biceps femoris long head (BFlh) and semitendinosus (ST) muscles, break-point angle (BPA), and the angle at peak BFlh EMG activity between bilateral and unilateral Nordic hamstring exercise (NHE) on a sloped platform.

Design: This study was designed as a case-control study.

Methods: Fourteen men participated in the study.

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The purpose of this study was to examine whether the NHE with an increased lower leg slope angle would enhance hamstring EMG activity in the final phase of the descend. The hamstring EMG activity was measured, the biceps femoris long head (BFlh) and the semitendinosus (ST). Fifteen male volunteers participated in this study.

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Choline is an important nutrient during pregnancy and lactation. Maternal choline deficiency in CD-1 mice lowers liver betaine levels in male offspring. By contrast, it increases elovl3 and vanin-1 mRNA levels in female offspring.

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Background: Evaluation of the effect of a pad on foot morphologies in patients with medial tibial stress syndrome (MTSS) requires more reliable and objective methods, rather than conventional subjective observations.

Objective: The objective of this study was to investigate the effect of pads on foot morphologies during quiet standing in athletes with MTSS.

Methods: We measured three-dimensional foot morphologies in 30 feet with MTSS and 40 healthy feet.

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Match demands in international men's lacrosse have yet to be explored. Therefore, this investigation quantified positional match demands of international men's lacrosse. This study quantified activity profiles of 50 lacrosse players [attack (AT): 11, midfield (MD): 22, defense (DF): 17] on Japan's national team, using a global positioning system (GPS), players' acceleration, and a heart rate (HR) apparatus to investigate their movement and physiological load.

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Background: This study was designed to quantify the relationship between the velocity at which lacrosse players can shoot a lacrosse ball (shot velocity) with a lacrosse stick and a variety of physical strength attributes.

Methods: Twenty lacrosse athletes were recruited to participate in the study. We measured shot velocity with a microwave, speed-measuring apparatus.

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This study aimed to investigate the in vivo kinematics of shear modulus of the lower leg muscles in patients with medial tibial stress syndrome (MTSS). The study population included 46 limbs with MTSS and 40 healthy limbs. The shear modulus of the medial head of the gastrocnemius, lateral head of the gastrocnemius, soleus, peroneus longus and tibialis anterior muscles were measured using shear wave ultrasound elastography.

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Background: The rearfoot motion during sports activities in patients with the medial tibial stress syndrome (MTSS) is unknown. This study aimed to investigate the difference in kinematics of the rearfoot in MTSS patients (eight male soccer players) and control participants (eight male soccer players) during a forward step.

Methods: Sixteen male soccer players, including eight players with MTSS, participated.

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The purpose of this study was to compare angular change and translational motion from the medial longitudinal arch (MLA) and lateral longitudinal arch (LLA) during running between medial tibial stress syndrome (MTSS) and non-MTSS subjects. A total of 10 subjects volunteered, comprising 5 subjects with MTSS and 5 subjects without injury (non-MTSS) as the control group. All subjects performed the test movement that simulated running.

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