Professional long distance runners achieve high efficiency at the cost of weak orbital stability.

Successful performance in long distance race requires both high efficiency and stability. Previous research has demonstrated the high running efficiency of trained runners, but no prior study quantitatively addressed their orbital stability. In this study, we evaluated the efficiency and orbital stability of 8 professional long-distance runners and compared them with those of 8 novices.

Effect of sprinting velocity on anterior cruciate ligament and knee load during sidestep cutting.

The purpose of the study was to investigate the effect of an increase in sprinting velocity on the anterior cruciate ligament (ACL) load, knee joint load, and activation of femoral muscles using the musculoskeletal modeling approach. Fourteen high school male athletes were recruited (age: 17.4 ± 0.

Complexity of Running and Its Relationship with Joint Kinematics during a Prolonged Run.

We investigated the effect of prolonged running on joint kinematics and its association with stride complexity between novice and elite runners. Ten elite marathoners and eleven healthy individuals took part in a 20 min submaximal prolonged running experiment at their preferred running speed (PRS). A three-dimensional motion capture system was utilized to capture and calculate the alpha exponent, stride-to-stride fluctuations (SSFs), and stride-to-stride variability (SSV) of spatiotemporal parameters and joint kinematics.

Analysis of the relationship between muscular strength and joint stiffness in children with Down syndrome during drop landing.

Background: Children with Down syndrome (DS) have critical biomechanical impairments such as increased ligamentous laxity, muscle hypotonia, and dysfunctional motor coordination, which makes performing everyday tasks challenging.

Objective: The purpose of the study was to explore the differences in the vertical joint stiffness, plantar force, and range of motion during drop landing for DS and age-matched typically developing children.

Methods: Six young male children with DS and age-matched seven healthy typically developing children (TD) assessed joint strength using an isokinetic dynamometer and performed five trials of single-leg drop jump using force platform and motion capture system.

Artificial neural network model effectively estimates muscle and fat mass using simple demographic and anthropometric measures.

Background & Aims: Lean muscle and fat mass in the human body are important indicators of the risk of cardiovascular and metabolic diseases. Techniques such as dual-energy X-ray absorptiometry (DXA) accurately measure body composition, but they are costly and not easily accessible. Multiple linear regression (MLR) models have been developed to estimate body composition using simple demographic and anthropometric measures instead of expensive techniques, but MLR models do not explore nonlinear interactions between inputs.

Analysis of the aging-induced changes in the motor ability structure using large population fitness test results.

Owing to confounding factors influencing the effect of aging, systematic analyses of age-related changes in motor ability are mostly limited to the use of animals whose diets and genetics can be controlled or the use of datasets of athletes who share similar lifestyles. However, we lack systematic methods for analyzing the effect of aging on the motor ability structure of the general public. We propose that principal component analysis (PCA) on fitness test results of a large sample may provide information on the aging-induced change in the motor ability structure of the general public.

Effect of Foot-Planting Strategy on Anterior Cruciate Ligament Loading in Women During a Direction Diversion Maneuver: A Musculoskeletal Modeling Approach.

Background: Although there is a higher prevalence of noncontact anterior cruciate ligament (ACL) injuries during a direction diversion maneuver (DDM), no previous studies have reported how foot-planting strategies affect ACL loading.

Purpose: To investigate the effect of foot-planting strategies on ACL loading in women during a DDM task using a musculoskeletal modeling approach.

Study Design: Descriptive laboratory study.

Aging induces a step-like change in the motor ability structure of athletes.

Many studies have investigated how aging decreases human strength and endurance. However, understanding the effect of aging on human motor ability requires more than knowledge of the separate temporal profile of individual motor function because the structure of human motor ability is multi-dimensional. We address the effect of aging on the multi-dimensional structure of human motor ability by investigating the performance records of athletes in track events across various age groups.

Effect of wearing a knee brace or sleeve on the knee joint and anterior cruciate ligament force during drop jumps: A clinical intervention study.

Background: Knee braces are considered to be extremely useful tools in reducing the shear force of knee joints for non-contact anterior cruciate ligament (ACL) injury prevention. However, the effectiveness of sports knee braces and sleeves remains to be identified. Therefore, the purpose of this study was to evaluate the effectiveness of wearing commercialized sports knee braces and sleeves on knee kinematics, kinetics, and ACL force during drop jumps using musculoskeletal modeling analysis.

Effect of prolonged racing on muscle activity and spatiotemporal variables: double-poling technique.

[Purpose] The purpose of this study was to examine the effect of a 40-minute race on muscle activity and spatiotemporal cycle variables at four-time points during a 12-km roller skiing test using the double-poling technique. [Subjects and Methods] Five elite cross-country (XC) skiers on the Korean National reserve team participated in the study. Part of a biathlon course that consisted of both flat land and slopes was selected, and three measurements were recorded after every 4-km lap.

Kicking modality during erratic-dynamic and static condition effects the muscular co-activation of attacker.

The purpose of the study was to investigate the effect of different kicking modality, i.e., erratic-dynamic target (EDT) versus static target (ST) on the performance of the roundhouse kick in two groups of taekwondo athletes of different skill level.

Potential of IMU Sensors in Performance Analysis of Professional Alpine Skiers.

In this paper, we present an analysis to identify a sensor location for an inertial measurement unit (IMU) on the body of a skier and propose the best location to capture turn motions for training. We also validate the manner in which the data from the IMU sensor on the proposed location can characterize ski turns and performance with a series of statistical analyses, including a comparison with data collected from foot pressure sensors. The goal of the study is to logically identify the ideal location on the skier's body to attach the IMU sensor and the best use of the data collected for the skier.