Wrist Posture Does Not Influence Finger Interdependence.
Authors: Chakrabhavi N, Skm V Abstract A task involving an instructed finger movement causes involuntary movements in the noninstructed fingers of the hand, also known as finger interdependence. It is associated with both mechanical and neural mechanisms. The current experiment investigated the effect of finger interdependence due to systematic changes of the wrist posture, close to neutral. Eight right-handed healthy human participants performed submaximal cyclic flexion and extension at the metacarpophalangeal joint at 0° neutral, 30° extension, and 30° flexion wrist postures, respectively. The experi...
Source: Journal of Applied Biomechanics - November 9, 2019 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Ankle and Midfoot Power During Single-Limb Heel Rise in Healthy Adults.
Authors: DiLiberto FE, Nawoczenski DA Abstract Although the midfoot is recognized to have an important role in the successful performance of a single-limb heel rise, healthy heel rise performance remains primarily characterized by ankle function. The purpose of this study was to examine the contribution of midfoot region power to single-limb heel rise in healthy adults. Participants (N = 12) performed 20 single-limb heel rises. An electromagnetic motion capture system and a force plate were used to record 3-segment foot motion and ground reaction forces. Inverse dynamic calculations were performed to obtain ankle a...
Source: Journal of Applied Biomechanics - November 9, 2019 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

The Effect of Holding an Object on Postural Stability and Suprapostural Task Performance.
This study assessed whether holding an object increased standing postural stability and improved the performance of a concurrent precision manual task. A total of 15 young adults performed a precision manual task with their dominant hand while holding or not holding an object in their nondominant hand. Postural stability was assessed using measures of postural sway and time to boundary. Suprapostural task performance was assessed as an error count. Holding did not influence postural sway or suprapostural task performance. Discrepancies among previous studies coupled with the present findings suggest that the effects of hol...
Source: Journal of Applied Biomechanics - October 30, 2019 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Statistical Parametric Mapping as a Measure of Differences Between Limbs: Applications to Clinical Populations.
This study demonstrated the ability of SPM to assess interlimb differences in lower-extremity movement during 2 example tasks: running and landing. Three-dimensional motion analysis was used to determine sagittal and frontal plane lower-extremity joint angles in (1) young and older individuals during running and (2) patients with anterior cruciate ligament reconstruction and uninjured control athletes during landing. Interlimb differences within each group were compared using SPM and paired t tests on peak discrete angles. No differences between limbs were found between young and older runners using SPM. Peak ank...
Source: Journal of Applied Biomechanics - October 21, 2019 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Autoregressive Modeling as Diagnostic Tool to Identify Postanterior Cruciate Ligament Reconstruction Limb Asymmetry.
This study implemented second-order autoregressive [AR(2)] modeling and its stationarity triangle to both quantitatively and visually delineate differences in dynamic stability from peak vGRF data in controls and post-anterior cruciate ligament reconstruction (ACLR) individuals during running. It was hypothesized that post-ACLR individuals would exhibit less dynamic stability than the controls, and that they would reside in a different location on the stationarity triangle, thus denoting differences in stability. The results presented supported the hypothesis that post-ACLR individuals exhibited significantly less dynamic ...
Source: Journal of Applied Biomechanics - October 21, 2019 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Accuracy and Reliability of Onset Detection Algorithms in Gait Initiation for Healthy Controls and Participants With Parkinson's Disease.
Authors: Chen A, Selvaraj S, Krishnan V, Asgari S Abstract Accurate and reliable detection of the onset of gait initiation is essential for the correct assessment of gait. Thus, this study was aimed at evaluation of the reliability and accuracy of 3 different center of pressure-based gait onset detection algorithms: A displacement baseline-based algorithm (method 1), a velocity baseline-based algorithm (method 2), and a velocity extrema-based algorithm (method 3). The center of pressure signal was obtained during 10 gait initiation trials from 16 healthy participants and 3 participants with Parkinson's disease. Int...
Source: Journal of Applied Biomechanics - October 21, 2019 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Chronic Ankle Instability Does Not Influence Tibiofemoral Contact Forces During Drop Landings Using a Musculoskeletal Model.
Authors: Li Y, Wang H, Simpson KJ Abstract The purpose of the study was to compare the tibiofemoral contact forces of participants with chronic ankle instability versus controls during landings using a computer-simulated musculoskeletal model. A total of 21 female participants with chronic ankle instability and 21 pair-matched controls performed a drop landing task on a tilted force plate. A 7-camera motion capture system and 2 force plates were used to test participants' lower-extremity biomechanics. A musculoskeletal model was used to calculate the tibiofemoral contact forces (femur on tibia). No significant betw...
Source: Journal of Applied Biomechanics - October 21, 2019 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

New Considerations for Wearable Technology Data: Changes in Running Biomechanics During a Marathon.
Authors: Clermont CA, Benson LC, Edwards WB, Hettinga BA, Ferber R Abstract The purpose of this study was to use wearable technology data to quantify alterations in subject-specific running patterns throughout a marathon race and to determine if runners could be clustered into subgroups based on similar trends in running gait alterations throughout the marathon. Using a wearable sensor, data were collected for cadence, braking, bounce, pelvic rotation, pelvic drop, and ground contact time for 27 runners. A composite index was calculated based on the "typical" data (4-14 km) for each runner and evalua...
Source: Journal of Applied Biomechanics - October 21, 2019 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

The Influence of Hip Structure on Functional Valgus Collapse During a Single-Leg Forward Landing in Females.
Authors: Hogg JA, Schmitz RJ, Shultz SJ Abstract Clinical femoral anteversion (Craig test) and hip range of motion (ROM) have been associated with valgus collapse, but their clinical usefulness in predicting biomechanics is unknown. Our purpose was to determine the individual and combined predictive power of femoral anteversion and passive hip ROM on 3-dimensional valgus collapse (hip internal rotation and adduction, knee rotation, and abduction) during a single-leg forward landing in females. Femoral anteversion and passive hip ROM were measured on 20 females (24.9 [4.1] y, 168.7 [8.0] cm, 63.8 [11.6]&nb...
Source: Journal of Applied Biomechanics - October 21, 2019 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

The Effect of Functional Knee Braces on Muscular Contributions to Joint Rotational Stiffness in Anterior Cruciate Ligament-Deficient and -Reconstructed Patients.
Authors: Derouin A, Potvin JR Abstract Functional knee braces are frequently prescribed by physicians to ameliorate the function of individuals with anterior cruciate ligament (ACL) injuries. These braces have been shown in the literature to potentially enhance knee stability by augmenting muscle activation patterns and the timing of muscle response to perturbations. However, very few techniques are available in the literature to quantify how those modifications in lower-limb muscle activity influence stability of the knee. The aim of the present study was to quantify the effect of an off-the-shelf functional knee ...
Source: Journal of Applied Biomechanics - September 23, 2019 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

The Receptive and Propulsive Behavior of Human Foot Joints During Running With Different Striking Strategies.
Authors: Deschamps K, Matricali G, Eerdekens M, Wuite S, Leardini A, Staes F Abstract Foot structure and kinematics have long been considered as risk factors for foot and lower-limb running injuries. The authors aimed at investigating foot joint kinetics to unravel their receptive and propulsive characteristics while running barefoot, both with rearfoot and with midfoot striking strategies. Power absorption and generation occurring at different joints of the foot in 6 asymptomatic adults were calculated using both a 3-segment and a 4-segment kinetic model. An inverse dynamic approach was used to quantify mechanical...
Source: Journal of Applied Biomechanics - September 23, 2019 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Effects of Eccentric Preloading on Concentric Vertical Jump Performance in Youth Athletes.
This study measured peak force (PF), peak rate of force development (PRFD), peak power (PP), concentric impulse, and eccentric impulse during static jump (SJ), countermovement jump (CMJ), and drop jump (DJ) in youth athletes to examine changes in vertical jump power with progressively greater eccentric preloading in relation to age, maturity, and muscle mass. Twenty-one males ranging from 6 to 16 years old performed the following vertical jumps in a random order: SJ, CMJ, and DJ from drop heights of 20, 30, and 40 cm (DJ20, DJ30, and DJ40, respectively). Measurements included PF, PRFD, PP, eccentric impulse, and conce...
Source: Journal of Applied Biomechanics - September 23, 2019 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Energetics of Walking With a Robotic Knee Exoskeleton.
Authors: MacLean MK, Ferris DP Abstract The authors tested 4 young healthy subjects walking with a powered knee exoskeleton to determine if it could reduce the metabolic cost of locomotion. Subjects walked with a backpack loaded and unloaded, on a treadmill with inclinations of 0° and 15°, and outdoors with varied natural terrain. Participants walked at a self-selected speed (average 1.0 m/s) for all conditions, except incline treadmill walking (average 0.5 m/s). The authors hypothesized that the knee exoskeleton would reduce the metabolic cost of walking uphill and with a load compared with walki...
Source: Journal of Applied Biomechanics - September 23, 2019 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Identification of Post-Concussion Dual-Task Gait Abnormalities Using Normative Reference Values.
We examined athletes with a concussion (n=54; mean age=20.3±1.1 years of age, 46% female, tested 2.9±1.5 days post-injury) and healthy controls tested during their preseason baseline examination (n=60; 18.9±0.7 years of age, 37% female). Participants completed an instrumented single/dual-task gait evaluation. Outcome variables included average walking speed, cadence, and step length. A significantly greater number of those with concussion walked with abnormal dual-task gait speed compared to the control group (56% vs. 30%; p= 0.008). After adjusting for potential confounding variables (age, concussion ...
Source: Journal of Applied Biomechanics - May 30, 2019 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Patients With Medial Knee Osteoarthritis Reduce Medial Knee Contact Forces by Altering Trunk Kinematics, Progression Speed, and Stepping Strategy During Stair Ascent and Descent: A Pilot Study.
This study assessed knee contact forces (KCF) and contact pressures during different stair negotiation strategies. Motion analysis was performed in five individuals with medial knee osteoarthritis (52.8±11.0 years) and eight healthy subjects (51.0±13.4 years) while ascending and descending a staircase. KCF and contact pressures were calculated using a multi-body knee model while performing step-over-step at controlled and self-selected speed, and step-by-step strategies. At controlled speed, individuals with osteoarthritis showed decreased peak KCF during stair ascent but not during stair descent. Osteoarthri...
Source: Journal of Applied Biomechanics - May 30, 2019 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Influence of Previous Iliotibial Band Syndrome on Coordination Patterns and Coordination Variability in Female Runners.
Authors: Foch E, Milner CE Abstract It is unknown if female runners that have sustained multiple iliotibial band syndrome occurrences run differently compared to runners that developed the injury once or controls. Therefore, the purpose of this study was to determine if differences existed in coordination patterns and coordination variability among female runners with recurrent iliotibial band syndrome, one iliotibial band syndrome occurrence, and controls. Overground running trials were collected for 36 female runners (n = 18 controls). Lower extremity coordination patterns were examined during running via a vecto...
Source: Journal of Applied Biomechanics - May 30, 2019 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Estimating the Maximum Isometric Force Generating Capacity of Wheelchair Racing Athletes for Simulation Purposes.
In this study, a sensitivity analysis was performed in OpenSim, whereby the maximum isometric force generating capacity of muscles was adjusted in 25% increments to literature defined values between scaling factors of 0.25x to 4.0x for two elite athletes, at three speeds representative of race conditions. Convergence of the solution was used to assess the results. Artificially weakening a model presented unrealistic values, and artificially strengthening a model excessively (4.0x) demonstrated physiologically invalid muscle force values. The ideal scaling factors were 1.5x and 1.75x for each of the athletes, respectively, ...
Source: Journal of Applied Biomechanics - May 30, 2019 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Does Decreasing Below-Knee Prosthesis Pylon Longitudinal Stiffness Increase Prosthetic Limb Collision and Push-Off Work During Gait?
This study observed the effects of different levels of pylon stiffness on individual limb work of unilateral below-knee prosthesis users walking at customary and fast speeds. Longitudinal stiffness reductions were associated with minimal increase in prosthetic limb collision and push-off work, but inconsistent changes in sound limb work. These small and variable changes in limb work did not suggest an improvement in mechanical economy due to reductions in stiffness. Fast walking generated greater overall center-of-mass work demands across stiffness conditions. Results indicate limb work asymmetry as the prosthetic limb exp...
Source: Journal of Applied Biomechanics - May 30, 2019 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Laboratory Performance Evaluation of Pristine and Used Headgear for Girls' Lacrosse.
Authors: Kelshaw PM, Gould TE, Jesunathadas M, Cortes N, Caswell A, Edwards ED, Caswell SV Abstract Girls' lacrosse participation and head injury rates have increased within the past decade. In response, optional headgear was implemented following the recently developed ASTM International (ASTM) lacrosse headgear performance standards. It remains unknown how lacrosse headgear responds to blunt impacts after use. Our purpose was to compare the peak linear acceleration (PLA) between girls' lacrosse headgear conditions (pristine and used) during blunt impacts. Pristine headgear (n=10) were tested in their original con...
Source: Journal of Applied Biomechanics - May 30, 2019 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Non-Linear Relation Between Upper Arm Volume and Maximal Effort Force Production.
The objective of the present study was to examine the relationship between maximal effort force production and anthropometric measures of upper arm volume. Thirty healthy young participants (15 women) performed five isokinetic concentric and eccentric maximal-effort elbow flexor/extensor contractions, on separate days. Measures of arm length, circumference, and skinfold/subcutaneous fat thickness were used to obtain a measure of arm volume, modeled as two separate right-angle frustra. Single variable regression analyses demonstrated significant (p
Source: Journal of Applied Biomechanics - May 30, 2019 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Running and Walking Foot Loading in Children Aged 4-10 Years.
Authors: Mesquita PR, Neri SGR, Lima RM, Manfio EF, de David AC Abstract While previous reports have provided normative plantar pressure data for walking in children, evaluation during running is lacking. Our study aimed to compare foot loading patterns during running and walking in children aged 4-10 years. Furthermore, the relationship between running baropodometric parameters and anthropometric measures was investigated. Foot loading of 120 volunteers was evaluated during running and walking using an Emed AT-4 pressure platform. Analyses were performed for 5 anatomical regions (rearfoot, midfoot, forefoot, hallu...
Source: Journal of Applied Biomechanics - April 30, 2019 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

The Effects of Data Padding Techniques on Continuous Relative Phase Analysis Using the Hilbert-Transform.
Authors: Ippersiel P, Preuss R, Robbins SM Abstract Continuous relative phase (CRP) analysis using the Hilbert-transform is prone to end-effects. The purpose was to investigate the impact of padding techniques (reflection, spline extrapolation, extraneous data, unpadded) on end-effects following Hilbert-transformed CRP calculations, using sinusoidal, non-sinusoidal, and kinematic data from a repeated sit-to-stand-to-sit task in adults with low-back pain (n=16, mean age=30 years). CRP angles were determined using a Hilbert-transform of sinusoidal and non-sinusoidal signals with set phase-shifts, and for the left thi...
Source: Journal of Applied Biomechanics - April 30, 2019 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

The Role of Sex and Physical Activity in Gait and Knee Extensor Function With Age.
Authors: Hafer JF, Miller MS, Kent JA, Boyer KA Abstract Older females experience higher rates of disability than males, potentially due to sex-specific differences in gait and muscle function. We evaluated the effects of age and physical activity (PA) on gait mechanics and knee extensor muscle function in males and females. Three groups of 20 individuals (each 10 females) participated: young (21-35 years), and highly and less active older (55-70 years) adults. Knee extensor strength and joint mechanics during preferred-speed gait were collected before and after 30 minutes of walking. Age by sex and PA by sex inter...
Source: Journal of Applied Biomechanics - April 30, 2019 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Dynamic Postural Control Is Influenced by Single-Leg Squat Speed and Depth Under Single-Task and Dual-Task Paradigms.
The objective of this study was to determine the relationships between squat parameters (speed and depth) and postural control under single-task and dual-task. Thirty healthy college students performed single-leg squats under single-task and dual-task with Stroop. Random intercepts general linear mixed models determined the effect of squat parameters on center of pressure parameters. For each 1 cm·s-1 increase in squat speed, sway range (medio-lateral: Beta = -0.03; antero-posterior: Beta = -0.05) and area (Beta = -0.25) decreased while sway speed (medio-lateral: Beta = 0.05; antero-posterior: Beta = 0.29; total: Be...
Source: Journal of Applied Biomechanics - April 30, 2019 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Characteristics of Contact Force and Muscle Activation During Choreographed Falls With Two Common Landing Techniques in Contemporary Dance.
This study investigated the contact forces and muscle activation during two choreographed fall techniques in contemporary dancers and how these were affected by the fall technique. Ten collegiate level dancers were instructed in two choreographed falls: a) an anteriorly-focused fall involving ankle plantar flexion, knee flexion, and hip flexion with dispersion of forces up the anterior surface of the shank (Technique 1); and (b) a laterally-focused fall involving inversion at the ankle with dispersion of forces up the lateral aspect of the shank (Technique 2). The knee and hip contact forces were 26.3% smaller (Technique 1...
Source: Journal of Applied Biomechanics - April 30, 2019 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Comparative Strength and Endurance Parameters of the Craniocervical and Cervicothoracic Extensors and Flexors in Females With and Without Idiopathic Neck Pain.
Authors: O Leary S, Hoogma C, Solberg ØM, Sundberg S, Pedler A, Van Wyk L Abstract Isometric strength and endurance performance of cervical flexor and extensor muscles were compared in women with (n = 30) and without (n = 30) idiopathic neck pain at the craniocervical and cervicothoracic axes. Strength and endurance time (time to task failure in seconds (s)) at 50% maximal voluntary contraction were recorded in 4 directions (craniocervical flexion/extension, cervicothoracic flexion/extension) and six strength and endurance ratios were calculated. Participants in both groups were matched for Body Mass Index. ...
Source: Journal of Applied Biomechanics - March 14, 2019 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

The Influence of Motion Control, Neutral and Cushioned Running Shoes on Lower Limb Kinematics.
Authors: Langley B, Cramp M, Morrison SC Abstract To-date there is a paucity of information about how different types of conventional running shoes influence lower limb kinematics. The aim of the study was to determine the influence of motion control, neutral and cushioned running shoes upon lower limb kinematics. Twenty-eight active males completed one test session running in standardised motion control, neutral and cushioned running shoes, on a treadmill at a self-selected pace (2.9 ± 0.6 m.s-1). Kinematic data were collected using a VICON motion analysis system with hip, knee and ankle joint angles calcul...
Source: Journal of Applied Biomechanics - March 14, 2019 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Differences in Maximum Voluntary Excitation Between Isometric and Dynamic Excitation are Age Dependent.
Authors: Baggen RJ, van Dieën JH, Verschueren SM, Van Roie E, Delecluse C Abstract In older populations, obtaining true maximum voluntary excitation appears more difficult than in young populations. The aims of this study were to determine whether differences between maximum voluntary excitation obtained from voluntary isometric contractions (MVIC) versus (sub-)maximum voluntary dynamic contractions (s-)MVDC) are age-dependent, and how normalizing EMG signals to corresponding maximum voluntary excitations affects variance between participants and the likelihood of normalized signals exceeding 100%. MVIC, s-MVD...
Source: Journal of Applied Biomechanics - March 14, 2019 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Anthropometric Changes During Pregnancy Provide Little Explanation of Dynamic Balance Changes.
Authors: Catena RD, Campbell N, Werner AL, Iverson KM Abstract We investigated the relationship between anthropometric changes and dynamic balance changes during pregnancy. Fifteen participants were recruited for testing, using a convenience sample, from 12 weeks gestation until childbirth. We measured body anthropometry with a tape measure and calipers. We conducted self-selected speed walking analysis using a motion capture system and measured balance deficits as increased motion of the body center of mass. While a relatively large total explained variance of preferred walking speed was achieved (R2 = 0.629, this...
Source: Journal of Applied Biomechanics - March 14, 2019 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Tests to Measure Core Stability in Laboratory and Field Settings: Reliability and Correlation Analyses.
Authors: Vera-Garcia FJ, López-Plaza D, Juan-Recio C, Barbado D Abstract Although core stability (CS) has been assessed through many different tests, the relationships among them are currently unknown. The main objective was to analyse the relationship between five representative tests used to assess CS in: i) laboratory settings: Sudden Loading Test (SLT) and Stable and Unstable Sitting Test (SUST); ii) field settings: Biering-Sorensen Test (BST), Three-Plane Core Strength Test (TPCT) and Double-leg Lowering Test (DLLT). The reliability of these tests was also examined. Thirty-three recreationally active ma...
Source: Journal of Applied Biomechanics - March 14, 2019 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Experimental Evaluation of Softball Protective Headgear for Defensive Play.
Authors: Strickland J, Bevill G Abstract The majority of head injuries sustained during softball play are due to defensive fielders being struck by a ball. The main objective of this study was to test the impact attenuation and facial protection capabilities of fielder's masks from softball impacts. Testing with an instrumented Hybrid III headform was conducted at two speeds and four impact locations for several protective conditions: six fielder's masks, one catcher's mask, and unprotected (no mask). The results showed that most fielder's masks reduced head accelerations, but not to the standard of catcher's masks...
Source: Journal of Applied Biomechanics - March 14, 2019 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Does a Perturbation Based Gait Intervention Enhance Gait Stability in Fall Prone Stroke Survivors? A Pilot Study.
Authors: Punt M, Bruijn SM, van de Port IG, de Rooij IJM, Wittink H, van Dieën JH Abstract A recent review indicated that perturbation based training (PBT) interventions are effective in reducing falls in older adults and patients with Parkinson's disease. It is unknown whether this type of intervention is effective in stroke survivors. We determined whether PBT can enhance gait stability in stroke survivors. Ten chronic stroke survivors who experienced falls in the past six months participated in the PBT. Participants performed 10 training sessions over a six-week period. The gait training protocol was progre...
Source: Journal of Applied Biomechanics - January 25, 2019 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Sprint Assessment Using Machine Learning and a Wearable Accelerometer.
This study aims to automate sprint assessment by estimating υ0 and τ using machine learning and accelerometer data. To this end, photocells recorded 10 m split times of 28 subjects for three 40 m sprints while wearing an accelerometer around the waist. Features extracted from the accelerometer data were used to train a classifier to identify the sprint start and regression models to estimate the sprint model parameters. Estimates of υ0, τ, and 30 m sprint time (t30) were compared between the proposed method and a photocell method using root mean square error (RMSE) and Bland-Altman analysis. The RMS...
Source: Journal of Applied Biomechanics - January 25, 2019 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Are Planar Simulation Models Affected by the Assumption of Coincident Joint Centres at the Hip and Shoulder?
Authors: Felton PJ, Yeadon MR, King MA Abstract Planar simulation models which assume coincident joint centres at the hip and shoulder are often used to investigate subject-specific maximal performances rather than 3D models due to the viability of determining subject-specific parameters. To investigate the effect of coincident joint centres on model accuracy, three variants of a 16-segment planar subject-specific angle-driven model were evaluated using an elite cricket fast bowling performance: (a) planar representation assuming coincident joint centres; (b) planar representation with non-coincident hip joint cent...
Source: Journal of Applied Biomechanics - January 25, 2019 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Complexity of Center of Pressure in Postural Control for Children With Autism Spectrum Disorders Was Partially Compromised.
Authors: Li Y, Mache MA, Todd TA Abstract The purpose of this study was to compare the complexity of postural control between children with autism spectrum disorder (ASD) and typical developing children during altered visual and somatosensory conditions using the multiscale entropy. Eleven children with ASD and 11 typical developing children were tested during quiet standing under four conditions: (1) eyes open and standing on a stable surface; (2) eyes open and standing on a compliant surface; (3) eyes closed and standing on a stable surface and (4) eyes closed and standing on a compliant surface. The COP data wer...
Source: Journal of Applied Biomechanics - January 25, 2019 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Activation-Dependent Changes in Soleus Length-Tension Behavior Augment Ankle Joint Quasi-Stiffness.
Authors: Clark WH, Franz JR Abstract The triceps surae muscle-tendon units are important in governing walking performance, acting to regulate mechanical behavior of the ankle through interaction between active muscle and passive elastic structures. Ankle joint quasi-stiffness (the slope of the relation between ankle moment and ankle rotation, kA), is a useful aggregate measure of this mechanical behavior. However, the role of muscle activation and length-tension behavior in augmenting kA remains unclear. Here, 10 subjects completed eccentric isokinetic contractions at rest and at two soleus activation levels (25% a...
Source: Journal of Applied Biomechanics - January 25, 2019 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Going Short: The Effects of Short Travel Key Switches on Typing Performance, Typing Force, Forearm Muscle Activity, and User Experience.
This study examined the effects of four micro-travel keyboards on forearm muscle activity, typing force, typing performance, and self-reported discomfort and difficulty. Twenty participants completed typing tasks on four commercially available devices with different key switch characteristics (dome, scissors, and butterfly) and key travels (0.55, 1.3, and 1.6 mm). The device with short travel (0.55 mm) and a dome type key switch mechanism was associated with higher muscle activities (6-8%,p
Source: Journal of Applied Biomechanics - January 25, 2019 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Letter to the Editor.
Authors: Tenan MS, Tweedell AJ, Haynes CA PMID: 30602330 [PubMed - as supplied by publisher] (Source: Journal of Applied Biomechanics)
Source: Journal of Applied Biomechanics - January 5, 2019 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Younger Total Knee Replacement Patients Do Not Demonstrate Gait Asymmetry for Heel Strike Transient or Knee Joint Moments that are Observed in Older Patients.
Authors: Street BD, Gage W Abstract Gait asymmetry is observed after total knee replacement (TKR), often leading to excessive forces at the contralateral limb. The number of TKR procedures has increased substantially over the past two decades, particularly among younger patients. Relatively little is known regarding these younger patients (
Source: Journal of Applied Biomechanics - December 13, 2018 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Postural Stability When Walking and Exposed to Mediolateral Oscillatory Motion: Effect of Oscillation Waveform.
This study investigated how the stability of walking people depends on the waveform of 1-Hz and 2-Hz mediolateral oscillations of the surface on which they walk. Walking on a treadmill, 20 subjects were perturbed by random oscillations of the treadmill with one-third octave bandwidths: different waveforms with the same r.m.s. acceleration and different waveforms with the same peak acceleration. Stability was measured subjectively and objectively by the velocity of the centre of pressure in the mediolateral direction. Subjective and objective measures of walking instability increased with increasing r.m.s. acceleration of o...
Source: Journal of Applied Biomechanics - December 13, 2018 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Kinematic Correlates of Kinetic Outcomes Associated With Running-Related Injury.
Authors: Napier C, MacLean CL, Maurer J, Taunton JE, Hunt MA Abstract High magnitudes and rates of loading have been implicated in the etiology of running-related injuries (RRI). Knowledge of kinematic variables that are predictive of kinetic outcomes could inform clinic-based gait retraining programs. Healthy novice female runners ran on a treadmill while 3D biomechanical data were collected. Kinetic outcomes consisted of vertical impact transient (VIT), average vertical loading rate (AVLR), instantaneous vertical loading rate (IVLR), and peak braking force (PBF). Kinematic outcomes included step length (SL); hip ...
Source: Journal of Applied Biomechanics - November 15, 2018 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

A PCA Approach to Quantifying Foot Clearance and Foot Clearance Variability.
Authors: Benson LC, Cobb SC, Hyngstrom AS, Keenan KG, Luo J, O'Connor KM Abstract Low foot clearance and high variability may be related to falls risk. Foot clearance is often defined as the local minimum in toe height during swing; however, not all strides have this local minimum. The primary purpose of this study was to identify a non-discrete measure of foot clearance during all strides, and compare discrete and non-discrete measures in ability to rank individuals on foot clearance and variability. Thirty-five participants (young adults (n=10), older fallers (n=10), older non-fallers (n=10), and stroke survivors...
Source: Journal of Applied Biomechanics - November 15, 2018 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Influence of Sacroiliac Bracing on Muscle Activation Strategies During Two Functional Tasks in Standing-Tolerant and Standing-Intolerant Individuals.
Authors: Edgar K, Appel A, Clay N, Engelsgjerd A, Hill L, Leeseberg E, Lyle A, Nelson-Wong E Abstract People who develop low back pain (LBP) during standing (standing-intolerant) are a sub-clinical group at risk for clinical LBP. Standing-intolerant individuals respond favorably to stabilization exercise, and may be similar to people with sacroiliac joint dysfunction (SIJD) that respond to stabilization approaches including sacroiliac joint (SIJ) bracing. The purpose was to characterize muscle activation and response to SIJ bracing in standing-tolerant and standing-intolerant individuals during forward flexion and ...
Source: Journal of Applied Biomechanics - November 15, 2018 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Three-Dimensional Kinematics and Power Output in Elite Para-Kayakers and Elite Able-Bodied Flat-Water Kayakers.
Authors: Bjerkefors A, Rosén JS, Tarassova O, Arndt A Abstract Trunk, pelvis and leg movement are important for performance in sprint kayaking. Para-kayaking is a new Paralympic sport in which athletes with trunk and/or leg impairment compete in three classification groups. The purpose of this study was to identify how physical impairments impact on performance by examining: differences in three-dimensional joint range of motion (RoM) between 10 (4 females, 6 males) elite able-bodied kayakers and 41 (13 females, 28 males) elite para-kayakersfrom the three classification groups, and which joint angles were co...
Source: Journal of Applied Biomechanics - October 10, 2018 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Comparing Anterior Cruciate Ligament Injury Risk Variables Between Unanticipated Cutting and Decelerating Tasks.
Authors: Peel SA, Schroeder LE, Sievert ZA, Weinhandl JT Abstract The purpose of this study was to examine the relationship between ACL injury risk factors in unanticipated cutting and decelerating. Three-dimensional kinematics and ground reaction forces were collected on eleven females (22±2yrs, 1.67±0.08m, 68.5±9.8kg) during two unanticipated tasks. Paired samples t-tests were performed to compare dependent variables between tasks. Spearman rank correlation coefficients were calculated to analyze the relationship between peak internal knee adduction moment and peak anterior tibial shear force...
Source: Journal of Applied Biomechanics - October 10, 2018 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Using a Support-Vector Machine Algorithm to Classify Lower Extremity EMG Signals During Running Shod/Unshod With Different Foot Strike Patterns.
In conclusion, based on EMG signals, the use a FFT to train a SVM was a better option to differentiate running forefoot/rearfoot than to use the DWT. Shod/barefoot running could not be differentiated. PMID: 30207195 [PubMed - as supplied by publisher] (Source: Journal of Applied Biomechanics)
Source: Journal of Applied Biomechanics - September 14, 2018 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Validating Virtual Time to Contact With Home Based Technology in Young and Older Adults.
This study aimed to validate VTC as measured by a depth sensor, and to determine if VTC from the depth sensor distinguishes between older adult fallers and non-fallers compared to a force platform. VTC was assessed in 10 young and 20 older adults by having participants lean in a circular direction followed by five balance tests: eyes open, dual task, eyes open foam, eyes closed, and eyes closed foam. Spearman's correlations and Bland-Altman plots were conducted to determine validity, and Receiver Operating Curves were constructed to discriminate between fallers and non-fallers. Significant correlations were found in the du...
Source: Journal of Applied Biomechanics - September 14, 2018 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Coordination Among Shank, Rearfoot, Midfoot and Forefoot Kinematic Movement During Gait in Individuals With Hallux Valgus.
Authors: Kawakami W, Takahashi M, Iwamoto Y, Shinakoda K Abstract An important step in the management of hallux valgus is the objective analysis of foot mechanics in dynamic conditions. However, the manner which hallux valgus affects the foot motion is poorly understood. Moreover, hallux valgus deformity may affect foot intersegmental coordination patterns. The purpose of this study was to investigate the relative motion and intersegmental foot coordination patterns, considering the midfoot, during gait in individuals with hallux valgus. Fifteen females with hallux valgus and 13 females without hallux valgus were r...
Source: Journal of Applied Biomechanics - September 14, 2018 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Skeletal Muscle Adaptations and Passive Muscle Stiffness in Cerebral Palsy: A Literature Review and Conceptual Model.
Authors: Tisha AL, Armstrong AA, Wagoner Johnson A, Lopez-Ortiz C Abstract This literature review focuses on the primary morphological and structural characteristics, and mechanical properties identified in muscles affected by spastic cerebral palsy (CP). CP is a non-progressive neurological disorder caused by brain damage and is commonly diagnosed at birth. Although the brain damage is not progressive, subsequent neuro-physiological developmental adaptations may initiate changes in muscle structure, function, and composition, causing abnormal muscle activity and coordination. The symptoms of CP vary among patients...
Source: Journal of Applied Biomechanics - September 14, 2018 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Generation of Linear Impulse During the Takeoff of the Long Jump.
This study investigates the effect of initial leg angle on horizontal jump performance. Eleven highly skilled male and female long jumpers (national and Olympic level) performed a series of horizontal jumps for distance. Within-jumper differences in initial leg angle, normalized horizontal and net vertical impulses, contact time, and average reaction force during the impact interval, post-impact interval, and in total were measured using highspeed video (240 or 300 Hz) and a force plate (1200 Hz). Pearson correlations, Winsorized correlations, and the HC4 method were used to determine significant correlations between varia...
Source: Journal of Applied Biomechanics - September 14, 2018 Category: Sports Medicine Tags: J Appl Biomech Source Type: research