Whole-body linear momentum control in two-foot running jumps in male basketball players.

Running jumps that depart the ground from two feet require momenta redirection upward from initial momenta that are primarily horizontal. It is not known how each leg generates backward and upward impulses from ground reaction forces to satisfy this mechanical objective when jumping to maximize height. We examined whole-body linear momentum control strategies during these two-foot running jumps by uncovering the roles of each leg in impulse generation.

Make an impact: going full circle together.

Sport diversification provides opportunities for individuals to develop physical literacy, establish a growth mindset, become more agile in varied environments, and develop robust strategies to improve performance. One could say the same for biomechanists, who study the control and dynamics of human movements in the context of sport. Through the lens of sport, we have focused on the ongoing interaction between the nervous system, musculoskeletal system, and the environment by using integrated experimental and modelling approaches to study well-practiced, goal-directed tasks in controlled laboratory and realistic field settings.

Dance-Themed National Biomechanics Day Community Engagement to Inspire our Future STEAM Leaders.

Community engagement experiences through National Biomechanics Day (NBD) that focused on dance biomechanics have provided excellent Science, Technology, Engineering, Art, and Math (STEAM) learning opportunities. During these experiences, bidirectional learning has been enjoyed by the biomechanists hosting the events and the kindergarten through 12th grade student attendees. In this article, perspectives are shared about dance biomechanics and hosting dance-themed NBD events.

Roles of each leg in impulse generation in professional baseball pitchers: preliminary findings uncover the contribution of the back leg towards whole-body rotation.

This study examined the roles of each leg in generating linear and angular impulses during baseball pitching. Professional pitchers (n = 4) pitched from a force plate instrumented mound, and 6-11 successful fastball pitches were used for analyses. We compared linear and angular impulses across the back and front legs.

Frontal plane balance during pre-planned and late-cued 90 degree turns while walking.

This study evaluated frontal-plane dynamic balance control during 90° left turns while walking. Ten healthy young adults performed straight-line gait, pre-planned turns, and turns cued visually (late-cued turns). We quantified rotational balance control via the range of frontal-plane angular momentum (Hf) about the center of mass (COM), and the relative positioning of the COM and the feet using the horizontal distance from the COM to the lateral edge of the base of support (lateral distance) and the mediolateral margin of stability (MOS).

Scapular and humeral elevation coordination patterns used before vs. after Reverse Total Shoulder Arthroplasty.

The purpose of this study was to compare scapulohumeral coordination used before and after Reverse Total Shoulder Arthroplasty (RTSA) during the ascent phase of scapular plane arm elevation tasks performed with varied shoulder rotations (neutral, external rotation, and internal rotation). We expected that after RTSA, participants would decrease scapulothoracic upward rotation angular displacement and increase the scapulohumeral rhythm (SHR) vs. before RTSA.

Quantifying warfighter performance during a bounding rush (prone-sprinting-prone) maneuver.

A single sacrum mounted inertial measurement unit (IMU) was employed to analyze warfighter performance on a bounding rush (prone-sprinting-prone) task. Thirty-nine participants (23M/16F) performed a bounding rush task consisting of four bounding rush cycles. The sacrum mounted IMU recorded angular velocity and acceleration data were used to provide estimates of sacral velocity and position.

Single-Arm, Non-randomized, Time Series, Single-Subject Study of Fecal Microbiota Transplantation in Multiple Sclerosis.

Emerging evidence suggests intestinal microbiota as a central contributing factor to the pathogenesis of Relapsing-Remitting-Multiple-Sclerosis (RRMS). This novel RRMS study evaluated the impact of fecal-microbiota-transplantation (FMT) on a broad array of physiological/clinical outcomes using deep metagenome sequencing of fecal microbiome. FMT interventions were associated with increased abundances of putative beneficial stool bacteria and short-chain-fatty-acid metabolites, which were associated with increased/improved serum brain-derived-neurotrophic-factor levels and gait/walking metrics.

Patient-specificity of scapular orientation measurements using an acromion marker cluster with multiple calibration poses.

The purpose of this study was to understand how each calibration pose affects scapular orientations measured by an Acromion Marker Cluster during scapular plane arm elevation performed by patients who had been pre-operatively indicated for Reverse Total Shoulder Arthroplasty. Eight pre-operative Reverse Total Shoulder Arthroplasty patients participated in this study while optical motion capture measured kinematics, specifically scapulothoracic angles and angular displacements, vs. humerothoracic elevation.

Body-worn IMU array reveals effects of load on performance in an outdoor obstacle course.

This study introduces a new method to understand how added load affects human performance across a broad range of athletic tasks (ten obstacles) embedded in an outdoor obstacle course. The method employs an array of wearable inertial measurement units (IMUs) to wirelessly record the movements of major body segments to derive obstacle-specific metrics of performance. The effects of load are demonstrated on (N = 22) participants who each complete the obstacle course under four conditions including unloaded (twice) and with loads of 15% and 30% of their body weight (a total of 88 trials across the group of participants).

Estimating Stair Running Performance Using Inertial Sensors.

Stair running, both ascending and descending, is a challenging aerobic exercise that many athletes, recreational runners, and soldiers perform during training. Studying biomechanics of stair running over multiple steps has been limited by the practical challenges presented while using optical-based motion tracking systems. We propose using foot-mounted inertial measurement units (IMUs) as a solution as they enable unrestricted motion capture in any environment and without need for external references.

Quantifying performance on an outdoor agility drill using foot-mounted inertial measurement units.

Running agility is required for many sports and other physical tasks that demand rapid changes in body direction. Quantifying agility skill remains a challenge because measuring rapid changes of direction and quantifying agility skill from those measurements are difficult to do in ways that replicate real task/game play situations. The objectives of this study were to define and to measure agility performance for a (five-cone) agility drill used within a military obstacle course using data harvested from two foot-mounted inertial measurement units (IMUs).

Are the hamstrings from the drive leg or landing leg more active in baseball pitchers? An electromyographic study.

Background: Ulnar collateral ligament reconstruction (UCLR) has become a common procedure among baseball players of all levels. There are several graft choices in performing UCLR, one of which is a hamstring (gracilis or semitendinosus) autograft. It is unclear whether the hamstring muscle from a pitcher's drive leg (ipsilateral side of the UCLR) or landing leg (contralateral side of the UCLR) is more active during the pitching motion.

Method for Estimating Three-Dimensional Knee Rotations Using Two Inertial Measurement Units: Validation with a Coordinate Measurement Machine.

Three-dimensional rotations across the human knee serve as important markers of knee health and performance in multiple contexts including human mobility, worker safety and health, athletic performance, and warfighter performance. While knee rotations can be estimated using optical motion capture, that method is largely limited to the laboratory and small capture volumes. These limitations may be overcome by deploying wearable inertial measurement units (IMUs).

Lower extremity control during turns initiated with and without hip external rotation.

The pirouette turn is often initiated in neutral and externally rotated hip positions by dancers. This provides an opportunity to investigate how dancers satisfy the same mechanical objectives at the whole-body level when using different leg kinematics. The purpose of this study was to compare lower extremity control strategies during the turn initiation phase of pirouettes performed with and without hip external rotation.

Whole-Body Balance Regulation during the Turn Phase of Piqué and Pirouette Turns with Varied Rotational Demands.

Objective: To compare dancers' balance regulation at the whole-body level under increased rotational demands during the turn phase of turns with and without large center-of-mass (CM) translation (i.e., piqué vs pirouette turns).

Modification of Impulse Generation During Pirouette Turns With Increased Rotational Demands.

This study determined how dancers regulated angular and linear impulse during the initiation of pirouettes of increased rotation. Skilled dancers (n = 11) performed single and double pirouette turns with each foot supported by a force plate. Linear and angular impulses generated by each leg were quantified and compared between turn types using probability-based statistical methods.

Modification of impulse generation during piqué turns with increased rotational demands.

During initiation of a piqué turn, a dancer generates impulse to achieve the desired lateral translation and whole-body rotation. The goal of this study was to determine how individuals regulate impulse generation when initiating piqué turns with increased rotational demands. Skilled dancers (n=10) performed single (∼360°) and double (∼720°) piqué turns from a stationary position.

Regulation of reaction forces during the golf swing.

During the golf swing, the reaction forces applied at the feet control translation and rotation of the body-club system. In this study, we hypothesized that skilled players using a 6-iron would regulate shot distance by scaling the magnitude of the resultant horizontal reaction force applied to the each foot with minimal modifications in force direction. Skilled players (n = 12) hit golf balls using a 6-iron.