Relationship between the ratio of increase in lean tissue to body weight gain and energy required to gain body weight in growing rats.

Although the energy stored in the lean tissue (LT) and adipose tissue (AT) is well known, the energy required to synthesise these tissues is obscure. Theoretically, the energy at the point at which ΔLT/Δ body weight (BW) reaches 100 % on a regression line, which indicates the relationship between ΔLT/ΔBW and the energy required for BW gain, is considered to be the energy expended to synthesise LT. Therefore, we investigated this relationship in rats.

Sex-Specific Differences in Peripheral Nerve Properties: A Comparative Analysis of Conduction Velocity and Cross-Sectional Area in Upper and Lower Limbs.

Peripheral nerve conduction velocity (NCV) and nerve cross-sectional area (nCSA) are crucial parameters in neurophysiological assessments, yet their sex-specific differences are not fully understood. This study investigated sex-based variations in NCV and nCSA between upper and lower limbs. Twenty participants (ten males and ten females) were recruited for this study.

Task-Dependent Mechanisms Underlying Prolonged Low-Frequency Force Depression.

Prolonged low-frequency force depression (PLFFD) is an intramuscular phenomenon involving the slow recovery of submaximal muscle strength following strenuous exercise. We hypothesize that the contribution of impaired excitation-contraction coupling processes to PLFFD is task dependent, and that they will be different between metabolically and mechanically demanding exercises. We also discuss evidence of the effectiveness of interventions to mitigate PLFFD.

Plyometric Exercise Transiently Enhances Twitch Torque but Fails to Enhance the Rate of Force Development Evaluated Using the Isometric Midthigh Pull.

The effects of jump exercises as a conditioning activity (CA) on the rate of force development (RFD) measured during the isometric midthigh pull (IMTP) have not been investigated. Therefore, we aimed to investigate the effect of the CA comprising three sets of five countermovement jumps on the RFD measured during the IMTP, and furthermore to investigate whether post-activity potentiation (PAP) would be involved in this mechanism. Thirteen healthy male university students (age: 19.

Magnetic Garments Promote Parasympathetic Dominance and Improve Sleep Quality in Male Long-Distance Runners Following a 30 km Run.

This study aimed to investigate the effects of high-intensity running on the autonomic nervous system and sleep quality of male long-distance runners and to examine the impact of wearing magnetic garments on these parameters. Fifteen highly trained male collegiate long-distance runners participated in a randomized, double-blind crossover study. Participants completed two 30 km runs (30k-RUN) during a 10-day training camp.

Evaluation of the Anatomical Cross-Sectional Area of Psoas Major Muscle Using an Ultrasound Imaging System Combined With an Inertial Measurement Unit: Improved Reliability in the US Using IMU-Based Positioning Techniques.

Recently, ultrasound (US) imaging has been used to estimate the cross-sectional area of skeletal muscle, but the reliability is uncertain. To improve the reliability of the US, we investigated skeletal muscle thickness measurement using an inertial measurement unit (IMU) to determine the direction of US beam incidence based on posture angle information. In addition, we examined whether the anatomical cross-sectional area (ACSA) of muscle can be estimated from the muscle thickness measured using the US with the IMU.

The Energy Required to Synthesize Lean and Adipose Tissue in Rats.

Although the energy stored in lean tissue (LT) and adipose tissue (AT) is well known, the energy required to synthesize these tissues is less clear. While elucidating the energy required for AT synthesis may not be so important, the elucidation of the energy required for LT synthesis is important for individuals who aim to increase their skeletal muscle. Theoretically the energy at the point at which ΔLT/Δbody weight (BW) reaches 100% on a regression curve, which indicates the relationship between ΔLT/ΔBW and the energy used to accumulate body tissue, is considered to be the energy expended to synthesize LT.

Fast and Stable Responses during Decision Making Require Strong Inhibitory Processes in Soccer Players.

Quick decision making is a vital factor for a successful pass in soccer games. Many previous studies of decision making in soccer focused on motor execution, but inhibitory processing has remained unclear. This study aimed to clarify the differences in motor execution and inhibitory among Japanese collegiate soccer players with different skill levels.

Quantification of Extramyocellular Lipids and Intramuscular Fat from Muscle Echo Intensity in Lower Limb Muscles: A Comparison of Four Ultrasound Devices against Magnetic Resonance Spectroscopy.

This study aimed to compare different ultrasound devices with magnetic resonance spectroscopy (MRS) to quantify muscle lipid content from echo intensity (EI). Four different ultrasound devices were used to measure muscle EI and subcutaneous fat thickness in four lower-limb muscles. Intramuscular fat (IMF), intramyocellular (IMCL) and extramyocellular lipids (EMCL) were measured using MRS.

Is the muscle-tendon architecture of non-athletic Kenyans different from that of Japanese and French males?

Background: In endurance running, elite Kenyan runners are characterized by longer thigh, shank, and Achilles tendon (AT) lengths combined with shorter fascicles and larger medial gastrocnemius (MG) pennation angles than elite Japanese runners. These muscle-tendon characteristics may contribute to the running performance of Kenyans. Furthermore, these specific lower-leg musculoskeletal architectures have been confirmed not only in elite Kenyan runners but also in non-athletic Kenyans since early childhood.

Glutathione depression alters cellular mechanisms of skeletal muscle fatigue in early stage of recovery and prolongs force depression in late stage of recovery.

The effects of reduced glutathione (GSH) on skeletal muscle fatigue were investigated. GSH was depressed by buthionine sulfoximine (BSO) (100 mg/kg body wt/day) treatment for 5 days, which decreased GSH content to ∼10%. Male Wistar rats were assigned to the control ( = 18) and BSO groups ( = 17).

Gaussian mixture modeling of acceleration-derived signal for monitoring external physical load of tennis player.

With the widespread use of wearable sensors, various methods to evaluate external physical loads using acceleration signals measured by inertial sensors in sporting activities have been proposed. Acceleration-derived external physical loads have been evaluated as a simple indicator, such as the mean or cumulative values of the target interval. However, such a conventional simplified indicator may not adequately represent the features of the external physical load in sporting activities involving various movement intensities.

Generalization of Psychosocial Skills to Life Skills in Collegiate Athletes.

This study investigated how needs-supportive and needs-thwarting coaching behaviors, basic need satisfaction (BNS), and basic need frustration (BNF) are positively or negatively related to collegiate athletes' generalization of psychosocial skills in competitive sports. Japanese collegiate athletes (N = 228, = 19.7 years) completed the measures to assess the study variables.

Quadriceps Function and Athletic Performance in Highly Trained Female Athletes.

Context: Quadriceps strength is considered a key contributor to performance in various athletic tasks. Yet, past research has reported conflicting results based on population, with little data available in highly trained female athletes.

Design: Cross-sectional.

An Experimental Feasibility Study Evaluating the Adequacy of a Sportswear-Type Wearable for Recording Exercise Intensity.

Sportswear-type wearables with integrated inertial sensors and electrocardiogram (ECG) electrodes have been commercially developed. We evaluated the feasibility of using a sportswear-type wearable with integrated inertial sensors and electrocardiogram (ECG) electrodes for evaluating exercise intensity within a controlled laboratory setting. Six male college athletes were asked to wear a sportswear-type wearable while performing a treadmill test that reached up to 20 km/h.

Muscle-tendon architecture in Kenyans and Japanese: Potential role of genetic endowment in the success of elite Kenyan endurance runners.

Aim: The specificity of muscle-tendon and foot architecture of elite Kenyan middle- and long-distance runners has been found to contribute to their superior running performance. To investigate the respective influence of genetic endowment and training on these characteristics, we compared leg and foot segmental lengths as well as muscle-tendon architecture of Kenyans and Japanese males (i) from infancy to adulthood and (ii) non-athletes versus elite runners.

Methods: The 676 participants were divided according to their nationality (Kenyans and Japanese), age (nine different age groups for non-athletes) and performance level in middle- and long-distance races (non-athlete, non-elite and elite adult runners).

Limb-Specific Features and Asymmetry of Nerve Conduction Velocity and Nerve Trunk Size in Human.

This study aimed to simultaneously examine the differences of human nerve conduction velocity (NCV) and nerve cross-sectional area (nCSA) between the upper and lower limbs and between different regions of the upper and lower limbs. Thirty healthy subjects volunteered for the study. NCV and nCSA of the ulnar and tibial nerves were measured with the dominant and non-dominant arms and the supporting and reacting legs using supramaximal electric stimulation and peripheral nerve ultrasonography at three regions for ulnar and tibial nerves, respectively.

Lower complexity of motor primitives ensures robust control of high-speed human locomotion.

Walking and running are mechanically and energetically different locomotion modes. For selecting one or another, speed is a parameter of paramount importance. Yet, both are likely controlled by similar low-dimensional neuronal networks that reflect in patterned muscle activations called muscle synergies.

Brain and muscle adaptation to high-fat diets and exercise: Metabolic transporters, enzymes and substrates in the rat cortex and muscle.

There is evidence suggesting that the effects of diet and physical activity on physical and mental well-being are the result of altered metabolic profiles. Though the central and peripheral systems work in tandem, the interactions between peripheral and central changes that lead to these altered states of well-being remains elusive. We measured changes in the metabolic profile of brain (cortex) and muscle (soleus and plantaris) tissue in rats following 5-weeks of treadmill exercise and/or a high-fat diet to evaluate peripheral and central interactions as well as identify any common adaptive mechanisms.

Acute effects of moderate-intensity cycling exercise on endothelial function in young healthy men: An investigation using the reactive hyperemia index.

Background: Endothelial cells play an important role in the prevention of cardiovascular disease.

Objective: In this study, we examined the effects of transient aerobic exercise on peripheral endothelial function.

Methods: Twenty-seven healthy male college students were selected as subjects and randomly divided into two groups: 13 in the control group and 14 in the exercise group.

Non-uniform distribution of passive muscle stiffness within hamstring.

Limited information is available on whether stiffness is different within and between the constituents of the hamstring, that is, the biceps femoris long head (BFlh), semitendinosus (ST), and semimembranosus (SM). Therefore, understanding of hamstring injuries and stretching effect on hamstring stiffness is difficult. The present study primarily aimed to identify whether passive muscle stiffness differs between the BFlh, ST, and SM and between the proximal, middle, and distal sites within each muscle.

COL5A1 rs12722 polymorphism is not associated with passive muscle stiffness and sports-related muscle injury in Japanese athletes.

Background: Poor joint flexibility has been repeatedly proposed as a risk factor for muscle injury. The C-to-T polymorphism (rs12722) in the 3'-untranslated region of the collagen type V α1 chain gene (COL5A1) is reportedly associated with joint flexibility. Flexibility of a normal joint is largely determined by passive muscle stiffness, which is influenced by intramuscular collagenous connective tissues including type V collagen.