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Countermovement Jump Variables And Estimated Peak Power In Female Children With Dynamic Knee Valgus, Mahdis Dadfar, Mehrshad Alipour, Rahman Sheikhhoseini

ISBS Proceedings Archive

The purpose of the current study was to evaluate countermovement jump biomechanical variables and to estimate peak power using different approaches in female children with dynamic knee valgus. Twenty-six female children, aged 10-14, with dynamic knee valgus were recruited. A Kistler force plate was used to record the kinetic data during three CMJ trials. Less peak power (estimated using allometric method) and greater landing force during countermovement jump were significantly correlated with valgus angle in female children (P= 0.033, R= -0.419, and P= 0.0.43, R= 0.413, respectively). Estimated peak power results using Sayers and Harman methods were significantly different from …

Differences In Lower Leg Kinetic Of Soccer Instep Kicking Between Female And Male Players, Tsuyoshi Iitake, Maya Hioki, Hitoshi Takahashi, Hiroyuki Nunome

ISBS Proceedings Archive

We aimed to clarify the difference in lower leg segment kinetics of soccer instep kicking between female and male players. Instep kicking of seven female and seven male university soccer players were captured at 500Hz. There was no significant difference between female and male groups for peak forward lower leg angular velocity while female players exhibited significantly smaller angular impulse due to knee joint moment than that of male players. On the other hand, female players showed comparable angular impulse due to the interaction moment acting on the lower leg to that of male players. It can be considered that …

Differences Between Control And Suppressed Arm Sprint Running During The Maximum Velocity Phase, Sam Gleadhill, Ryu Nagahara

ISBS Proceedings Archive

The purpose of this study was to clarify sprint characteristic differences between control and suppressed arm sprint running during the maximum velocity phase. Baseball players (n=15) completed a 50 m control and suppressed arm trial, and ground reaction force was measured with force platforms. Sprint characteristics were calculated during the stride that maximum velocity was reached. Cohen’s d effect size with 95% confidence intervals and paired T-tests elucidated differences between trials. The maximum velocity decreased by 7.06% during the suppressed arm trial, compared to the control, probably caused by the suppressed arm condition. There were further decreases in propulsive (12.67%), …

Assessment Of Kinematic Cmj Data Using A Deep Learning Algorithm-Based Markerless Motion Capture System, Gerda Strutzenberger, Robert Kanko, Scott Selbie, Hermann Schwameder, Kevin Deluzio

ISBS Proceedings Archive

The purpose of this study was to compare the performance of a video-based markerless motion capture system to a conventional marker-based approach during a counter movement jump (CMJ). Twenty-three healthy participants performed CMJ while data was collected simultaneously via a marker-based (Oqus) and a 2D video-based motion capture system (Miqus, both: Qualisys). The video data was further processed to 3D-data using Theia3D (Theia Markerless Inc.). Excellent agreement between systems with ICCs >0.99 exists for jump height (mean average error of -0.27 cm) and sagittal ankle and knee plane angles (RMSD < 5°). The hip joint showed an average RMSD of 21° with a strong correlation of 0.80. As such the markerless system is capable of detecting jump height, sagittal ankle and knee joint angles and 3D joint positions of a CMJ to a high accuracy

The Rapid Stretch Stimulus Does Not Enhance Muscle Strength In Active Individuals Following A 4-Week Proprioceptive Neuromuscular Strengthening Protocol., Aditi P. Vyas, Sarah Breen

ISBS Proceedings Archive

Proprioceptive neuromuscular facilitation (PNF) a technique widely used as a training modality among physically active individuals. PNF in the upper limb is combined with the rapid stretch stimulus at the beginning of every repetition of resistive diagonal PNF. The stretch stimulus is applied at the palm of the hand & fingers in the opposite direction to activate receptors. The aim of the study was to evaluate the effects of stretch stimulus with PNF exercises over 4-weeks for improvements in muscle strength. Eight participants were recruited & randomly divided into the CG, n=4 with no stretch stimulus & EG, n=4 with …

Interlimb Asymmetries In Ground Reaction Force Time-Series During Bi-Lateral Countermovement Jumps, Nayun Ahn

ISBS Proceedings Archive

Principal component analysis (PCA) of waveforms can provide useful information about biomechanical patterns throughout a movement. The purposes of this study were to 1) use PCA to identify interlimb asymmetries in the ground reaction force (GRF) time-series data of the left and right leg during a bi-lateral countermovement jump (CMJ) and 2) determine if asymmetries in GRF time-series were associated with CMJ performance. Eight female collegiate soccer players performed three maximal effort CMJ. PCA extracted five principal components (PC) scores, eigenvalues, and eigenvectors from the GRF data. PC2 scores differed significantly between two legs, but only PC3 scores were positively …

Within-Subject Repeatability And Between-Subject Variability In Posture During Calibration Of An Inertial Measurement Unit System, Byron Donaldson, Helen Bayne, Neil E. Bezodis

ISBS Proceedings Archive

Inertial measurement units (IMUs) are a valuable tool for field based sports research, but within- and between-subject comparisons may be affected by variation in the 0° position established by a standing calibration position. This study assessed within-subject repeatability and between-subject variability in IMU sensor orientations during calibration. Calibration posture was reliable within-subjects given standardised instructions (typical error < 1.9°). Sensor angles relative to a global vertical axis had large between-subject ranges for upper spine (21–35°), lower spine (1–23°) and pelvis (11–35°), while lower limb segment angles had much lower variability (0-6°). Thus, a standing calibration posture is repeatable within participants given suitable instructions, however variability in standing posture may need to be accounted for before making between-subject comparisons, particularly with regard to spine and pelvis segments.

Handstand Balance Motor Control Mechanisms, Moira Pryhoda, Karl Newell, Gareth Irwin

ISBS Proceedings Archive

The goal of a handstand, a fundamental skill in gymnastics, is to maintain a balanced stance by controlling center of mass (COM) position. Successful handstands predominantly use wrist torque to control the COM in the anterior-posterior (AP) plane. The aim of this study was to determine the underlying motor control mechanisms necessary to maintain a strong handstand stance through analysis of joint angle and COM position variability. Full body 3D kinematic data were collected on three competitive level gymnasts during 30 s floor handstands. Variability of joint angles were consistently higher than the center of mass, demonstrating that joints self-organize …

Medio-Lateral Acceleration Of Female Athletes With An Acl Reconstruction In Comparison With A Healthy Population, Siân Atkinson, Holly A. Stock, Ezio Preatoni

ISBS Proceedings Archive

We assessed change of direction abilities in team sport female athletes. Ten participants returned to full activity from ACL reconstruction (ACLR) for longer than one year and 10 healthy controls (CON) were compared. Twelve maximal effort 45° cutting manoeuvres from the reconstructed side (ACLR) or a random selection of both sides (CON) were analysed for each individual using a motion capture system. CON showed greater medio-lateral centre of mass (COM) acceleration between 51 and 75 % of ground contact. CON reported increased ankle plantar flexor power from 94 to 98 % of foot contact, with also a higher peak. Although …

Continuous Changes In Leg Stiffness Using A Mass-Spring-Damper Model With An Actuator During The Step Phase Of The Triple Jump, Junki Yamamoto, Terumitsu Miyazaki, Sekiya Koike, Norihisa Fujii

ISBS Proceedings Archive

The purpose of this study was to examine a calculation method of the leg stiffness using the simplified leg model for evaluating the continuous changes in leg stiffness during the step phase of the triple jump. The leg stiffness is the ratio of the ground reaction forces to a displacement of the simplified leg length. We compared the difference in the leg stiffness between the previous method and the proposed method in this study. There was a non-linear and exponential relationship between the displacement of the simplified leg length and the elastic force. The peak value of leg stiffness calculated …

Lower Body Musculotendon Unit Function During Bounding, Hurdle Jumping And Running, Danielle Trowell, Aaron Fox, Natalie Saunders, Bill Vicenzino, Jason Bonacci

ISBS Proceedings Archive

To facilitate exercise prescription, this study compared the function of six lower limb musculotendon units during plyometric exercises with running. Fourteen distance runners performed overground running (3.89 m/s), bounding, and hurdle jumps. Computational simulations were used to compare musculotendon unit function, peak powers, and total work. Compared to running, the hurdle jumps had greater gluteus maximus peak power absorption (12.1%; SMD 0.65), and gluteus maximus (15.7%; SMD 0.51) and soleus (16.5%; SMD 0.92) total negative work. Hurdle jumps may be an appropriate exercise when higher eccentric loads of the gluteus maximus and soleus are required. Compared to running, bounding had …

Development And Evaluation Of A Deep Learning Based Markerless Motion Capture System, Laurie Needham

ISBS Proceedings Archive

This study presented a deep learning based markerless motion capture workflow and evaluated performance against marker-based motion capture during overground running. Multi-view high speed (200 Hz) image data were collected concurrently with marker-based motion capture (ground-truth data) permitting a direct comparison between methods. Lower limb kinematic data for six participants demonstrated high levels of agreement for lower limb joint angles with average RMSE ranging between 2.5° - 4.4° for hip sagittal and frontal plane motion, and 4.2° - 5.2° for knee and ankle motion. These differences generally fall within the known uncertainties of marker-based motion capture, suggesting that our markerless …

Lateral Edge Friction Variability In Indoor Sports Shoes, Timo Bagehorn, Lasse Jakobsen, Ion M. Sivebæk, Uwe G. Kersting, Filip Gertz Lysdal

ISBS Proceedings Archive

It has previously been speculated that the occurrence and severity of lateral ankle sprain injuries is linked to excessive shoe-surface friction. The purpose of this study was to assess the amount of lateral edge friction in indoor sports shoes, and evaluate the variation from the traditional forefoot traction test. Therefore, we modified the ISO:12387:2019 test for slip resistance and positioned the shoe on its lateral edge while simulating a sideways movement. All tests were conducted on an indoor surface. In general, we found that lateral edge friction on average was 22% lower than forefoot friction (p<0.0001). However, linear regression showed that the forefoot test could only explain 63% of the variation in edge friction, thereby suggesting that a lateral test is needed to adequately inform on lateral edge friction. Future research is planned to determine whether a noticeable change in friction coefficient is also a ‘valuable change’, hence potentially having clinical implications for injury prevention.

Rock Climbing Helmet Impact Performance Varies By Helmet Model Type, Blake Scicli, John E. Goff, Mark Begonia, Bethany Rowson

ISBS Proceedings Archive

The purpose of this study was to compare the impact performance of a sample of rock climbing helmets. Each helmet was impacted at three locations (front, side, and back) and three impact speeds (2 m/s, 3.85 m/s, and 5 m/s) using a custom pendulum impactor. Peak resultant linear and rotational accelerations were compared by impact speed. The results of this study show that acceleration varies by helmet model and impact location. Differences in acceleration by helmet model support the need for relative performance ratings of rock climbing helmets. These tests can be used as the basis of methods to compare …

Three Dimensional Kinematic Differences Between Male And Female Soccer Players, Danyon Loud, Paul Grimshaw, Richard Kelso

ISBS Proceedings Archive

This research describes a method of biomechanical analysis that allows for kinematic data to be captured in a game-like environment and key biomechanical differences between male and female soccer players to be identified. Male (n=3) players aged between 22 and 24 years and female players (n=3) aged between 19 and 23 years were recorded using a VICON motion capture system operating outdoors at an artificial grass venue. Biomechanical measurements of the lower limb such as inversion/eversion and flexion/extension of the ankle; the flexion/extension, varus/valgus and internal/external rotation of the knee; and the internal/external rotation and abduction/adduction of the hip, were …

Effects Of Ageing On Gait Complexity, Arezoo Amirpourabasi, Jia Yi Chow, Sarah Elizabeth Lamb, J.R. Lawrence Kwek, Genevieve Williams

ISBS Proceedings Archive

Ageing alters gait patterns that influences the control mechanism of human movement. The aim of this study was to identify the age-related differences in complexity of gait kinematics. Gait is a fundamental but complex action, and loss of complexity has been suggested with ageing. In this study multiscale entropy (MSE) analysis was used to investigate complexity in gait. Whole body kinematic data for 10 younger adults (21±1.84 years old) and 10 older adults (62.7±2.2 years old) running at 9 km/h on the treadmill for 2 minutes were analysed. Body centre of mass (CoM) were calculated. MSE of CoM position, and …

Effect Of Lower Extremities Position On Volleyball Attack Take-Off Height, Alejandro C. Martinez, Nicole A. Marquez, Chengtu Hsieh

ISBS Proceedings Archive

The purpose of this study was to investigate the influence of volleyball attack take-off technique on the centre of mass (CoM) take-off height. The kinematics of lower extremities at take-off was obtained via 3D motion analysis. Results showed that the group with greater normalised attack height (HA) had greater normalised CoM take-off height (p < 0.01) than the group with lower normalised attack height (LA). Additionally, the HA group had a greater inter-ankle distance at take-off (p < 0.05) than the LA group. There was no significant difference in CoM horizontal distance between the groups. The findings of this study indicate that the normalised CoM take-off height for a volleyball attack is neither influenced by the feet position at take-off nor by the horizontal CoM distance from take-off to ball impact.

Joint- And Load-Specific Asymmetries During Three Lower Extremity Resistance Training Exercises, Michael H. Haischer, Nayun Ahn, Hoon Kim, Emily Jacobson, Kristof Kipp

ISBS Proceedings Archive

The purpose of this study was characterize the consistency of limb symmetries at the knee and hip in the front squat, hexagonal barbell deadlift, and Romanian deadlift across three loads (40%, 60%, 80% of front squat one-repetition maximum). Eight female collegiate soccer players performed three repetitions at each aforementioned load and for each exercise while motion capture and ground reaction force data were recorded. Bilateral net joint moments were calculated and used to quantify joint-specific limb symmetry indices (LSI) for each exercise and loading condition. Correlation analyses revealed similarity in LSI at the knee and hip within all exercises and …

The Relationship Between Angular Momentum Of The Lower Trunk And Shoulder Joint Forces During An Overarm Throw, Kevin Moore, Suzanne Konz, Mark Timmons, Steven Leigh

ISBS Proceedings Archive

The proximal-to-distal force transfer of the kinetic chain in overarm throwing has well-established movements. The nature of the transfer of momentum from the lower trunk to the shoulder during an overarm throw remains to be determined. This study explored correlations between angular momentum about the superior-inferior axis of the lower trunk and compressive and anterior shear forces at the shoulder in experienced baseball players as they made maximum effort throws from the outfield. We found no association between the maximum lower trunk angular momentum during the arm cocking phase and shoulder joint anterior shear force at ball release (r …

Shot Performance And Cue Stick Kinematics Of Top Spin Shots In Cue Sports Players Of Various Playing Levels, Pui Wah Kong, Jing Wen Pan, John Komar, Chen Yang

ISBS Proceedings Archive

This study aimed to compare the shot performance and kinematics of the cue stick in top spin shots between less-skilled and skilled players. Twenty-five cue sports players were recruited and assigned to the less-skilled (n = 12) or skilled (n = 13) groups. Ten successful top spin trials were recorded for each participant. 2D video analysis was employed to evaluate shot performance which was represented by an error distance. A 3D motion capture system was used to obtain kinematic data of the cue stick during the cueing movement. The results showed that skilled players were more consistent in their performance …

Assessment Of A Markless Motion Tracking Method To Determine Body Position On The Bike, Rodrigo Bini, Gil Serrancolí, Paulo Roberto Pereira Santiago, Felipe Moura

ISBS Proceedings Archive

This study compared body position on the bicycle using manual and automatically determined body segments during stationary cycling. High speed video (120 fps) was obtained from 14 cyclists using their own bikes on a stationary cycle trainer in a single session. Torso, hip, knee and ankle angles were measured in two positions of the crank (3 o’clock and 6 o’clock-dynamically) to determine body position on the bike. Significant differences (3-12°, d=0.38-1.92) were observed for all joints between the manual and automated method for both crank positions (except for the ankle at the 6 o’clock). Overall, the automated method overestimated torso …

A Kinematic Comparison Of Conventional Inswing And Outswing Bowling In Cricket, Cody Lindsay, Wayne Spratford

ISBS Proceedings Archive

Swing bowling is an important facet of cricket, however, it has received little consideration from researchers. This study compared the bowling action and initial ball flight kinematics of inswing and outswing deliveries in 15 (male = 12, female = 3) pathway and high-performance medium and fast pace bowlers. Participants delivered the ball with their forearm, hand and the seam of the ball angled towards and away from the batter for inswing and outswing with an extended wrist flexing at ball release. Therefore, significant differences were found in forearm orientation (p < 0.001), hand orientation (p < 0.001), seam azimuth angle (p < 0.001) and swing angle (p < 0.001). By identifying similarities and differences of inswing and outswing, this study could benefit coaches to improve swing bowling performance in bowlers and provide a foundation for future research.

No Dataset Too Small! Animating 3d Motion Data To Enlarge 2d Video Databases, Marion Mundt, Henrike Oberlack, Corey Morris, Johannes Funken, Wolfgang Potthast, Jacqueline Alderson

ISBS Proceedings Archive

This study outlines a technique to leverage the wide availability of high resolution three-dimensional (3D) motion capture data for the purpose of synthesising two-dimensional (2D) video camera views, thereby increasing the availability of 2D video image databases for training machine learning models requiring large datasets. We register 3D marker trajectories to generic 3D body-shapes (hulls) and use a 2D pose estimation algorithm to predict joint centre and anatomical landmark keypoints in the synthesised 2D video views – a novel approach that addresses the limited data available in elite sport settings. We use 3D long jump data as an exemplar use …

Perspectives And Practices Of Accredited Tennis Coaches When Developing Stroke Technique, Nicholas Busuttil, Alexandra Hannah Roberts, Marcus Dunn, Kane Middleton

ISBS Proceedings Archive

The purpose of this study was to understand current international tennis coaching standards related to the development of specific grip positions in tennis and to explore tennis coaches’ opinions on using physically constraining training tools for effective skill development. Accredited tennis coaches (n = 237) from 33 countries completed an anonymous online survey about their perspectives on the importance of grip positions for effective stroke development, and opinions on using physically constraining training tools for skill development. In the early stages of a player’s technical development, training grip positions was ranked as the second most important aspect of foundational technique. …

Trunk Biomechanics Of Transtibial Amputees In Level And Sloped Gait Using Rigid, Hydraulic And Microprocessor Controlled Ankles, Thede Preiser, Cleveland Barnett, Hermann Schwameder, Gerda Strutzenberger

ISBS Proceedings Archive

Compensational gait mechanisms, as an increased mediolateral trunk lean, are associated with the development of lower back pain, which is common among individuals with transtibial amputation (TTA). Therefore, the aim of this study was to investigate if different prosthetic ankle devices influence mediolateral trunk angles during gait in TTA. Six TTA and six controls walked in the level and on a positive and negative 5° inclined instrumented ramp using a rigid (RIG), a hydraulic (HYD) and a microprocessor (MPC) ankle component (Chas A Blatchford and Sons, Basingstoke, UK). Prosthetic design did not significantly affect the mediolateral trunk lean in any …

Comparison Of Marker And Marker-Less Automated Motion Capture For Baseball Pitching Biomechanics, Glenn Fleisig, Jonathan S. Slowik, Derek Wassom, Jasper Bishop, Alek Z. Diffendaffer

ISBS Proceedings Archive

The purpose of this study was to measure baseball pitching kinematics with a marker-less motion capture system and compare the results against marker-based measurements. A sample of 114 pitches were captured at 240 Hz simultaneously with a 9-camera marker-less system and a 12-camera marker system. The pitches were thrown by nine baseball pitchers (age 17.0 ± 4.0 yrs). For each trial, the data were time-synchronized between the two systems using the instant of ball release. Coefficient of Multiple Correlations (CMC) were computed to assess the similarity of waveforms between the two systems. Paired t-tests were used to compare differences between …

Predicting Ground Reaction Forces From 2d Video: Bridging The Lab To Field Nexus, Molly Goldacre, Amar El-Sallam, Hannah Wyatt, William Johnson, Jian Liu, Ajmal Mian, Jacqueline Alderson

ISBS Proceedings Archive

The accurate measurement of ground reaction forces (GRFs) is confined to laboratory-based settings. This poses an ongoing problem for sports biomechanists working in the field given the necessity of this variable for input into the commonly employed inverse dynamics modelling approach. In addition, GRFs are also used by the wider sport science community for assessing player “workload” metrics. Non-invasive in-field estimation of GRFs could facilitate the development of an in-field tool which has the potential to revolutionise the side-line management of players from a number of perspectives. The aim of this study was to use a least squares estimator (LSE) …

Isbs 2021 Conference Proceedings Title And Foreward, Wayne Spratford, Celeste Coltman, Nick Brown, John Warmenhoven

ISBS Proceedings Archive

The ISBS is an international society totally dedicated to biomechanics in sports, whose primary purposes are:

• To provide a forum for the exchange of ideas for sports biomechanics researchers, coaches and teachers.
• To bridge the gap between researchers and practitioners.
• To gather and disseminate information and materials on biomechanics in sports.

The conference planned for Canberra, Australia did not go ahead in a face-to-face capacity due to COVID-19. The conference was instead delivered fully online. These proceedings are the accepted papers for the online conference.

Papers underwent a double blinded review process. Each paper in these proceedings has been reviewed …

Air-Spun Silk-Based Micro-/Nanofibers And Thin Films For Drug Delivery, Christopher R Gough, Xiao Hu

College of Science & Mathematics Departmental Research

Micro-/nanofibers have shown high promise as drug delivery vehicles due to their high porosity and surface-area-to-volume ratio. The current study utilizes air-spraying, a novel fiber fabrication technique, to create silk micro-/nanofibers without the need for a high voltage power source. Air-spraying was used to create silk fibrous mats embedded with several model drugs with high efficiency. In order to compare the effect of biomaterial geometry on the release of the model drugs, silk films were also created and characterized. Fourier-transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and a drug release study were …

The Bison, September 3, 2021

The Bison Newspapers

No abstract provided.