Eight-Week Inspiratory Muscle Training Alters Electromyography Activity of the Ankle Muscles During Overhead and Single-Leg Squats: A Randomized Controlled Trial.
This study was conducted to evaluate the effects of 8-week inspiratory muscle training on activity in the ankle muscles of athletes with chronic low-back pain. A randomized controlled trial involving 45 men and women with chronic low-back pain was carried out. Electromyography activity in the tibialis anterior, peroneus longus, gastrocnemius medialis, and gastrocnemius lateralis muscles of the dominant leg was recorded. Secondary outcomes included biopsychosocial indices, such as pain, disability, anxiety and depression, fear-avoidance beliefs, and fear of (re)injury. Static and dynamic overhead squat tests showed that ins...
Source: Journal of Applied Biomechanics - October 15, 2020 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

A Comparison of Clinical Spinal Mobility Measures to Experimentally Derived Lumbar Spine Passive Stiffness.
Authors: Tennant LM, Nelson-Wong E, Kuest J, Lawrence G, Levesque K, Owens D, Prisby J, Spivey S, Albin SR, Jagger K, Barrett JM, Wong JD, Callaghan JP Abstract Spinal stiffness and mobility assessments vary between clinical and research settings, potentially hindering the understanding and treatment of low back pain. A total of 71 healthy participants were evaluated using 2 clinical assessments (posteroanterior spring and passive intervertebral motion) and 2 quantitative measures: lumped mechanical stiffness of the lumbar spine and local tissue stiffness (lumbar erector spinae and supraspinous ligament) measured v...
Source: Journal of Applied Biomechanics - October 15, 2020 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

The Efficacy of Simultaneously Training 2 Motion Targets During a Squat Using Auditory Feedback.
Authors: Hale RF, Dorgo S, Gonzalez RV, Hausselle J Abstract Auditory feedback is a simple, low-cost training solution that can be used in rehabilitation, motor learning, and performance development. The use has been limited to the instruction of a single kinematic or kinetic target. The goal of this study was to determine if auditory feedback could be used to simultaneously train 2 lower-extremity parameters to perform a bodyweight back squat. A total of 42 healthy, young, recreationally active males participated in a 4-week training program to improve squat biomechanics. The Trained group (n = 22) received 4 week...
Source: Journal of Applied Biomechanics - October 7, 2020 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Effect of Grade and Surface Type on Peak Tibial Acceleration in Trained Distance Runners.
Authors: Waite N, Goetschius J, Lauver JD Abstract Runners experience repeated impact forces during training, and the culmination of these forces can contribute to overuse injuries. The purpose of this study was to compare peak vertical tibial acceleration (TA) in trained distance runners on 3 surface types (grass, asphalt, and concrete) and 3 grades (incline, decline, and level). During visit 1, subjects completed a 1-mile time trial to determine their pace for all running trials: 80% (5%) of the average time trial velocity. During visit 2, subjects were outfitted with a skin-mounted accelerometer and performed 18...
Source: Journal of Applied Biomechanics - October 7, 2020 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Lessons Learned.
Authors: van Dieen J PMID: 32998107 [PubMed - as supplied by publisher] (Source: Journal of Applied Biomechanics)
Source: Journal of Applied Biomechanics - October 2, 2020 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Lumbar Intervertebral Kinematics During an Unstable Sitting Task and Its Association With Standing-Induced Low Back Pain.
This study used video fluoroscopy to assess lumbar spine intervertebral kinematics of people who do and do not develop standing-induced low back pain during a seated chair-tilting task. A total of 9 females and 8 males were categorized as pain developers (5 females and 3 males) or nonpain developers (4 females and 5 males) using a 2-hour standing exposure; pain developers reported transient low back pain and nonpain developers did not. Participants were imaged with sagittal plane fluoroscopy at 25 Hz while cyclically tilting their pelvises anteriorly and posteriorly on an unstable chair. Intervertebral angles, relativ...
Source: Journal of Applied Biomechanics - September 26, 2020 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Effect of Increased Lumbar Lordosis on Lumbar Multifidus and Longissimus Thoracis Activation During Quadruped Exercise in Patients With Chronic Low Back Pain: An EMG Study.
The objective was to investigate the electromyographic activity of the lumbar multifidus (MF) muscle and longissimus thoracis muscle, along with their activity ratio (MF longissimus thoracis ratio), during quadruped stabilization exercise performed with neutral posture and with increased lumbar lordosis in patients with chronic low back pain (CLBP). A total of 23 patients with CLBP (12 females and 11 males) were recruited based on inclusion and exclusion criterion. Each patient performed 4 exercises in random order, with surface electromyography electrodes and an electrogoniometer attached. A cross-sectional study design w...
Source: Journal of Applied Biomechanics - September 24, 2020 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Estimating Muscle Forces for Breast Cancer Survivors During Functional Tasks.
Authors: Lang AE, Kim SY, Milosavljevic S, Dickerson CR Abstract Breast cancer survivors have known scapular kinematic alterations that may be related to the development of secondary morbidities. A measure of muscle activation would help understand the mechanisms behind potential harmful kinematics. The purpose of this study was to define muscle force strategies in breast cancer survivors. Shoulder muscle forces during 6 functional tasks were predicted for 25 breast cancer survivors (divided by impingement pain) and 25 controls using a modified Shoulder Loading Analysis Module. Maximum forces for each muscle were c...
Source: Journal of Applied Biomechanics - September 24, 2020 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Effects of Student Interests on Engagement and Performance in Biomechanics.
This study investigates the effects of student interests on engagement and performance in 10th grade students enrolled in a summer program for students underrepresented in the science, technology, engineering, and mathematics fields. The authors assessed the effects of interest-tailored lectures on student engagement and performance in a 5-week program with bioengineering workshops, focusing on the delivery of biomechanics content. A total of 31 students received interest-tailored lectures (intervention) and 23 students received only generic lectures (control) in biomechanics. In addition, the authors assessed the effects ...
Source: Journal of Applied Biomechanics - September 24, 2020 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Lower-Extremity Motor Synergies in Individuals With and Without Chronic Ankle Instability.
Authors: Jagodinsky AE, Angles R, Wilburn C, Weimar WH Abstract Current theoretical models suggest that ankle sprain copers exhibit movement adaptations contributing to the avoidance of chronic ankle instability. However, few studies have examined adaptations at the level of biomechanical motor synergies. The purpose was to examine characteristics of the support moment synergy between individuals with chronic ankle instability, copers, and healthy individuals. A total of 48 individuals participated in the study. Lower-extremity kinetics and variability in the moment of force patterns were assessed during the stance...
Source: Journal of Applied Biomechanics - September 17, 2020 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Expanding Our Scope to Include Biomechanics Education and Outreach.
Authors: Bigelow K, Madigan ML PMID: 32919378 [PubMed - as supplied by publisher] (Source: Journal of Applied Biomechanics)
Source: Journal of Applied Biomechanics - September 15, 2020 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Examination of the Feasibility of a 2-Dimensional Portable Assessment of Knee Joint Stability: A Pilot Study.
In this study, the position of a knee marker was tracked in 2-dimensional planes to predict biomechanical variables associated with ACL injury risk. Three-dimensional kinematics and ground reaction forces were collected during bilateral, single-leg stop-jump tasks for 44 healthy male military personnel. Knee marker position data were extracted to construct 2-dimensional 95% prediction ellipses in each anatomical plane. Knee marker variables included: ellipse areas, major/minor axes lengths, orientation of ellipse axes, absolute ranges of knee position, and medial knee collapse. These variables were then used as predictor v...
Source: Journal of Applied Biomechanics - September 15, 2020 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Experiences of Undergraduates Publishing Biomechanics Research.
Authors: McErlain-Naylor SA Abstract The aim of this study was to investigate student experiences of publishing undergraduate research in biomechanics. A total of 29 former students with experience of publishing peer-reviewed undergraduate biomechanics research completed an online survey regarding their perceived benefits, level of involvement, and experiences in aspects of the research process. On average, students perceived their experiences to be "largely helpful" or greater in all aspects. Areas were identified corresponding to: the greatest perceived benefits (eg, understanding of the research p...
Source: Journal of Applied Biomechanics - September 15, 2020 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Comparison of Transverse Plane Tibial and Frontal Plane Rearfoot Motion and Movement Coordination Between Runners With Medial Tibial Stress Syndrome and Healthy Controls.
Authors: Langley B, Knight N, Morrison SC Abstract Medial tibial stress syndrome (MTSS) is a common running-related injury. Alterations in movement patterns and movement coordination patterns have been linked to the development of overuse injuries. The aim of this study was to compare transverse plane tibial and frontal plane rearfoot motion and the coordination of these movements between runners with MTSS and healthy controls. A total of 10 recreational runners with MTSS and 10 healthy controls ran at 11 km/h on a treadmill. A 3-camera motion analysis system operating at 200 Hz was used to calculate tibi...
Source: Journal of Applied Biomechanics - September 15, 2020 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Can Treadmill Slip-Perturbation Training Reduce Longer-Term Fall Risk Upon Overground Slip Exposure?
Authors: Lee A, Bhatt T, Liu X, Wang Y, Wang S, Pai YC Abstract The purpose was to examine and compare the longer-term generalization between 2 different practice dosages for a single-session treadmill slip-perturbation training when reexposed to an overground slip 6 months later. A total of 45 older adults were conveniently assigned to either 24 or 40 slip-like treadmill perturbation trials or a third control group. Overground slips were given immediately after initial training, and at 6 months after initial training in order to examine immediate and longer-term effects. The performance (center of mass stability a...
Source: Journal of Applied Biomechanics - August 28, 2020 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Effect of Vastus Medialis Loss on Rabbit Patellofemoral Joint Contact Pressure Distribution.
Authors: Han SW, Sawatsky A, Jinha A, Herzog W Abstract Vastus medialis (VM) weakness is thought to alter patellar tracking, thereby changing the loading of the patellofemoral joint (PFJ), resulting in patellofemoral pain. However, it is challenging to measure VM force and weakness in human studies, nor is it possible to measure the associated mechanical changes in the PFJ. To obtain fundamental insight into VM weakness and its effects on PFJ mechanics, the authors determined PFJ loading in the presence of experimentally simulated VM weakness. Skeletally mature New Zealand White rabbits were used (n = 6), and the v...
Source: Journal of Applied Biomechanics - August 28, 2020 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Development of a Full Flexion 3D Musculoskeletal Model of the Knee Considering Intersegmental Contact During High Knee Flexion Movements.
Authors: Kingston DC, Acker SM Abstract A musculoskeletal model of the right lower limb was developed to estimate 3D tibial contact forces in high knee flexion postures. This model determined the effect of intersegmental contact between thigh-calf and heel-gluteal structures on tibial contact forces. This model includes direct tracking and 3D orientation of intersegmental contact force, femoral translations from in vivo studies, wrapping of knee extensor musculature, and a novel optimization constraint for multielement muscle groups. Model verification consisted of calculating the error between estimated tibial com...
Source: Journal of Applied Biomechanics - August 28, 2020 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Could Relative Movement Between the Adductor Muscles and the Skin Invalidate Surface Electromyography Measurement?
Authors: Elsais WM, Preece SJ, Jones RK, Herrington L Abstract The superficial hip adductor muscles are situated in close proximity to each other. Therefore, relative movement between the overlying skin and the muscle belly could lead to a shift in the position of surface electromyography (EMG) electrodes and contamination of EMG signals with activity from neighboring muscles. The aim of this study was to explore whether hip movements or isometric contraction could lead to relative movement between the overlying skin and 3 adductor muscles: adductor magnus, adductor longus, and adductor gracilis. The authors also s...
Source: Journal of Applied Biomechanics - August 17, 2020 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Center of Pressure, Vertical Ground Reaction Forces, and Neuromuscular Responses of Special-Forces Soldiers to 43-km Load Carriage in the Field.
Authors: Scales J, O'Driscoll JM, Coleman D, Giannoglou D, Gkougkoulis I, Ntontis I, Zisopoulou C, Brown M Abstract The primary purpose of this study was to examine lateral deviations in center of pressure as a result of an extreme-duration load carriage task, with particular focus on heel contact. A total of 20 (n = 17 males and n = 3 females) soldiers from a special operation forces unit (body mass 80.72 [21.49] kg, stature 178.25 [8.75] cm, age 26 [9] y) underwent gait plantar pressure assessment and vertical jump testing before and after a 43-km load carriage event (duration 817.02 [32.66] m...
Source: Journal of Applied Biomechanics - August 17, 2020 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Vertical Jump Testing in Rugby League: A Rationale for Calculating Take-Off Momentum.
Authors: McMahon JJ, Lake JP, Ripley NJ, Comfort P Abstract The purpose of this study was to determine the usefulness of calculating jump take-off momentum in rugby league (RL) by exploring its relationship with sprint momentum, due to the latter being an important attribute of this sport. Twenty-five male RL players performed 3 maximal-effort countermovement jumps on a force platform and 3 maximal effort 20-m sprints (with split times recorded). Jump take-off momentum and sprint momentum (between 0 and 5, 5 and 10, and 10 and 20 m) were calculated (mass multiplied by velocity) and their relationship determine...
Source: Journal of Applied Biomechanics - August 17, 2020 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Movement Coordination During Humeral Elevation in Individuals With Newly Acquired Spinal Cord Injury.
Authors: Finley MA, Euiler E, Hiremath SV, Sarver J Abstract Humeral elevation is a critical motion for individuals who use a manual wheelchair given that, in a typical day, wheelchair users reach overhead 5 times more often than able-bodied controls. Kinematic analyses in individuals with chronic spinal cord injury (SCI) have focused on weight-bearing tasks rather than overhead reaching. This technical report presents shoulder movement coordination during overhead reaching in individuals with newly acquired SCI. Eight volunteers with acute SCI and 8 matched, uninjured controls participated. Three-dimensional kinem...
Source: Journal of Applied Biomechanics - August 17, 2020 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Effects of Increased Step-Width on Knee Biomechanics During Inclined and Declined Walking.
Authors: Sample DW, Thorsen TA, Weinhandl JT, Strohacker KA, Zhang S Abstract The purpose of this study was to investigate effects of preferred step width and increased step width modification on knee biomechanics of obese and healthy-weight participants during incline and decline walking. Seven healthy-weight participants and 6 participants who are obese (body mass index ≥ 30) performed 5 walking trials on level ground and a 10° inclined and declined instrumented ramp system at both preferred and wide step-widths. A 2 × 2 (step-width × group) mixed-model analysis of variance was used to examine ...
Source: Journal of Applied Biomechanics - August 13, 2020 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Tibial Acceleration Reliability and Minimal Detectable Difference During Overground and Treadmill Running.
Authors: Aubol KG, Hawkins JL, Milner CE Abstract Measurements of tibial acceleration during running must be reliable to ensure valid results and reduce errors. The purpose of this study was to determine the reliability and minimal detectable difference (MDD) of peak axial and peak resultant tibial acceleration during overground and treadmill running. The authors also compared reliability and MDDs when peak tibial accelerations were determined by averaging 5 or 10 trials. Tibial acceleration was measured during overground and treadmill running of 19 participants using a lightweight accelerometer mounted to the tibi...
Source: Journal of Applied Biomechanics - August 13, 2020 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Standardized Lab Shoes Do Not Decrease Loading Rate Variability in Recreational Runners.
Authors: Hunter JG, Smith AMB, Sciarratta LM, Suydam S, Shim JK, Miller RH Abstract Studies of running mechanics often use a standardized lab shoe, ostensibly to reduce variance between subjects; however, this may induce unnatural running mechanics. The purpose of this study was to compare the step rate, vertical average loading rate, and ground contact time when running in standardized lab shoes versus participants' normal running shoes. Ground reaction forces were measured while the participants ran overground in both shoe conditions at a self-selected speed. The Student's t-test revealed that the vertical averag...
Source: Journal of Applied Biomechanics - August 1, 2020 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Contact Pressures Between the Rearfoot and a Novel Offloading Insole: Results From a Finite Element Analysis Study.
Authors: Strayer ST, Moghaddam SRM, Gusenoff B, Gusenoff J, Beschorner KE Abstract Pressure offloading is critical to diabetic foot ulcer healing and prevention. A novel product has been proposed to achieve this offloading with an insole that can be easily modified for each user. This insole consists of pressurized bubbles that can be selectively perforated and depressurized to redistribute weight to the nonulcer region of the foot. However, the effect of the insole design parameters, for example, bubble height and stiffness, on offloading effectiveness is unknown. To this end, a 3-dimensional finite element model ...
Source: Journal of Applied Biomechanics - August 1, 2020 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Landing Biomechanics in Adolescent Athletes With and Without a History of Sports-Related Concussion.
Authors: Avedesian JM, Covassin T, Dufek JS Abstract Recent evidence suggests previously concussed athletes are at greater risk for lower-extremity (LE) injuries than are controls. However, little is known regarding the influence of sports-related concussion (SRC) on landing biomechanics that may provide a mechanistic rationale for LE injury risk. The purpose of this investigation was to examine LE drop-landing biomechanics in adolescent athletes with and without a previous SRC history. Participants included 10 adolescent athletes with an SRC history and 11 controls from multiple sports. Three-dimensional kinematic...
Source: Journal of Applied Biomechanics - August 1, 2020 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Automated Classification of Postural Control for Individuals With Parkinson's Disease Using a Machine Learning Approach: A Preliminary Study.
In conclusion, participants with PD exhibited impaired postural stability and their postural sway features could be identified by machine learning algorithms. PMID: 32736341 [PubMed - as supplied by publisher] (Source: Journal of Applied Biomechanics)
Source: Journal of Applied Biomechanics - August 1, 2020 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Effects of Metatarsal Work Boots on Gait During Level and Inclined Walking.
This study aimed to measure the effects of 4 safety work boots, steel toe, and steel toe with metatarsal protection in wader- and hiker-style boots, on level and inclined walking gait characteristics, during ascent and descent. A total of 10 participants completed this study. A motion capture system measured kinematics that allowed for the calculation of key gait parameters. Results indicated that gait parameters changed due to incline, similar to previous literature. Wader-style work boots reduced ankle range of motion when ascending an incline. Hip, knee, and ankle ranges of motion were also reduced during descent for th...
Source: Journal of Applied Biomechanics - July 28, 2020 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Lessons Learned.
Authors: Potvin J PMID: 32702662 [PubMed - as supplied by publisher] (Source: Journal of Applied Biomechanics)
Source: Journal of Applied Biomechanics - July 25, 2020 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Lessons Learned.
Authors: Gregor RJ PMID: 32659741 [PubMed - as supplied by publisher] (Source: Journal of Applied Biomechanics)
Source: Journal of Applied Biomechanics - July 15, 2020 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Quantifying Segmental Contributions to Center-of-Mass Motion During Dynamic Continuous Support Surface Perturbations Using Simplified Estimation Models.
This study aimed to quantify the contributions of body segments (ie, trunk, head, upper extremity, and lower extremity) to the control of center-of-mass (COM) movement during continuous, multidirectional, support surface perturbations. Three-dimensional, whole-body kinematics were captured while 10 participants experienced 5 minutes of perturbations. Anteroposterior, mediolateral, and vertical COM position and velocity were calculated using a full-body model and 7 models with reduced numbers of segments, which were compared with the full-body model. With removal of body segments, errors relative to the full-body ...
Source: Journal of Applied Biomechanics - July 15, 2020 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Muscular Coordination of Single-Leg Hop Landing in Uninjured and Anterior Cruciate Ligament-Reconstructed Individuals.
This study compared lower-limb muscle function, defined as the contributions of muscles to center-of-mass support and braking, during a single-leg hopping task in anterior cruciate ligament-reconstructed (ACLR) individuals and uninjured controls. In total, 65 ACLR individuals and 32 controls underwent a standardized anticipated single-leg forward hop. Kinematics and ground reaction force data were input into musculoskeletal models to calculate muscle forces and to quantify muscle function by decomposing the vertical (support) and fore-aft (braking) ground reaction force components into contributions by individual lower-lim...
Source: Journal of Applied Biomechanics - July 15, 2020 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Effects of Optimization Technique on Simulated Muscle Activations and Forces.
Authors: Roelker SA, Caruthers EJ, Hall RK, Pelz NC, Chaudhari AMW, Siston RA Abstract Two optimization techniques, static optimization (SO) and computed muscle control (CMC), are often used in OpenSim to estimate the muscle activations and forces responsible for movement. Although differences between SO and CMC muscle function have been reported, the accuracy of each technique and the combined effect of optimization and model choice on simulated muscle function is unclear. The purpose of this study was to quantitatively compare the SO and CMC estimates of muscle activations and forces during gait with the experime...
Source: Journal of Applied Biomechanics - July 15, 2020 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Impairments of Postural Balance in Surgically Treated Lumbar Disc Herniation Patients.
Authors: Rosker ZM, Rosker J, Sarabon N Abstract Reports on body sway control following microdiscectomy lack reports on side-specific balance deficits as well as the effects of trunk balance control deficits on body sway during upright stances. About 3 weeks post microdiscectomy, the body sway of 27 patients and 25 controls was measured while standing in an upright quiet stance with feet positioned parallel on an unstable support surface, a tandem stance with the involved leg positioned in front or at the back, a single-leg stance with both legs, and sitting on an unstable surface. Velocity, average amplitude, and ...
Source: Journal of Applied Biomechanics - June 24, 2020 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Older Adults Overcome Reduced Triceps Surae Structural Stiffness to Preserve Ankle Joint Quasi-Stiffness During Walking.
Authors: Krupenevich RL, Clark WH, Sawicki GS, Franz JR Abstract Ankle joint quasi-stiffness is an aggregate measure of the interaction between triceps surae muscle stiffness and Achilles tendon stiffness. This interaction may be altered due to age-related changes in the structural properties and functional behavior of the Achilles tendon and triceps surae muscles. The authors hypothesized that, due to a more compliant of Achilles' tendon, older adults would exhibit lower ankle joint quasi-stiffness than young adults during walking and during isolated contractions at matched triceps surae muscle activations. The au...
Source: Journal of Applied Biomechanics - June 7, 2020 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Which Are the Key Kinematic and Kinetic Components to Distinguish Recovery Strategies for Overground Slips Among Community-Dwelling Older Adults?
Authors: Wang S, Wang Y, Pai YC, Wang E, Bhatt T Abstract Slip outcomes are categorized as either a backward loss of balance (LOB) or a no loss of balance (no-LOB) in which an individual does not take a backward step to regain their stability. LOB includes falls and nonfalls, while no-LOB includes skate overs and walkovers. Researchers are uncertain about which factors determine slip outcomes and at which critical instants they do so. The purpose of the study was to investigate factors affecting slip outcomes in proactive and early reactive phases by analyzing 136 slip trials from 68 participants (age: 72.2 [5.3]&n...
Source: Journal of Applied Biomechanics - June 4, 2020 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Anterior-Posterior Balance Perturbation Protocol Using Lifelike Virtual Reality Environment.
The objective of this study was to investigate different configurations of amplitude and frequency in an anterior-posterior translation VR environment, that is, lifelike and scaled. Thirteen young adults with no conditions affecting balance were recruited. Balance was challenged by anterior-posterior sinusoidal movement of the lab image within the VR headset. Four different amplitudes of the sinusoidal movement were tested: 1, 5, 10, and 20 cm, with each amplitude being presented at 2 test frequencies : 0.5 and 0.25 Hz. Mean center of pressure velocity was significantly greater than baseline at 0.5 Hz and am...
Source: Journal of Applied Biomechanics - May 13, 2020 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Sensitivity of Neuromechanical Predictions to Choice of Glenohumeral Stability Modeling Approach.
Authors: McFarland DC, Brynildsen AG, Saul KR Abstract Most upper-extremity musculoskeletal models represent the glenohumeral joint with an inherently stable ball-and-socket, but the physiological joint requires active muscle coordination for stability. The authors evaluated sensitivity of common predicted outcomes (instability, net glenohumeral reaction force, and rotator cuff activations) to different implementations of active stabilizing mechanisms (constraining net joint reaction direction and incorporating normalized surface electromyography [EMG]). Both EMG and reaction force constraints successfully reduced ...
Source: Journal of Applied Biomechanics - May 6, 2020 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Stable and Unstable Load Carriage Effects on the Postural Control of Older Adults.
Authors: Walsh GS, Low DC, Arkesteijn M Abstract The aim of this study was to investigate the effects of backpack load carriage on quiet standing postural control and limits of stability (LOS) of older adults. Fourteen older adults (65 [6] y) performed quiet standing and a forward, right, and left LOS test in 3 conditions, unloaded, stable, and unstable backpack loads while activity of 4 leg muscles was recorded. Stable and unstable loads decreased postural sway (main effect ηp2=.84, stable P
Source: Journal of Applied Biomechanics - May 6, 2020 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Interactive Association Between Mechanical and Sensorimotor Aspects of Cervical Extensor Muscles: Implications for Chronic Neck Pain.
Authors: Ghamkhar L, Amiri Arimi S, Kahlaee AH Abstract While proprioceptive functioning of the cervical extensor muscles has been proposed to be associated with chronic neck pain (NP), the mechanism by which such impairment might contribute to NP is not clear. The aim of this cross-sectional study was to investigate the relevance of proprioception, extensor muscles size, and endurance to chronic NP. A total of 60 participants with (n = 30) or without (n = 30) chronic NP participated in this cross-sectional study. Joint repositioning error (JRE), ultrasonographic parameters of the cervical extensors, and clinical e...
Source: Journal of Applied Biomechanics - May 2, 2020 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Comparisons of Knee Extensor Functional Demand During Gait by Age, Physical Activity Level, and the Impact of Acute Exercise and Walking Speed.
Authors: Hafer JF, Boyer KA Abstract The link between age-related changes in muscle strength and gait is unclear. We tested if knee extensor functional demand differs by age and physical activity status and if functional demand increases with walking speed or after exercise. Gait and knee extensor muscle torque were collected from young adults and highly and less active older adults before and after treadmill walking. Functional demand was the ratio of knee moments during gait to knee extensor muscle torques estimated from participant-specific torque-velocity curves. Functional demand at the peak knee flexion momen...
Source: Journal of Applied Biomechanics - April 28, 2020 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Standing Balance Performance and Knee Extensors' Strength in Diabetic Patients with Neuropathy.
Authors: Younesian H, Farahpour N, Mazde M, Simoneau M, Turcot K Abstract Diabetes peripheral neuropathy (DPN) leads to balance impairment among diabetes mellitus (DM). The aims of this study were to (1) distinguish between DM patients who have/do not have DPN and to (2) compare quadriceps' strength and balance performance of DM, DPN, and healthy groups. Fifteen healthy females and 33 females with type 2 diabetic patients participated. The electrodiagnostic method was used to classify diabetic patients into DM and DPN. A dynamometer was used to measure quadriceps' strength. Single-leg standing on a force ...
Source: Journal of Applied Biomechanics - April 28, 2020 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Timing of Strain Response of the ACL and MCL Relative to Impulse Delivery During Simulated Landings Leading up to ACL Failure.
The objective of this study was to precisely quantify the timing associated with ligament strain during simulated landing and injury events. The hypotheses tested were that the timing of peak strain following initial contact would differ between ligaments and that peak strain timing would be independent of the injury-risk profile emulated during simulated landing. A mechanical impact simulator was used to perform landing simulations based on various injury-risk profiles that were applied to each specimen in a block-randomized order. The ACL and medial collateral ligament were instrumented with strain gauges that recorded c...
Source: Journal of Applied Biomechanics - April 23, 2020 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Effects of Self-Selected Step Length and Trunk Position on Joint Kinetics in Highly Physically Fit Older Adults.
Authors: Krupenevich RL, Miller RH Abstract The causes of age-related differences in lower-extremity joint moments and powers are unknown. The purpose of this study was to determine the effects of highly physically active older adults walking with (1) a step length similar to young adults and (2) an upright trunk posture, on hip and ankle joint kinetics. The authors hypothesized that, compared with their self-selected walking mechanics, older adults would exhibit decreased hip kinetics and increased ankle kinetics when prescribed a young adult step length, and would exhibit decreased hip extension moments...
Source: Journal of Applied Biomechanics - April 9, 2020 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

The Relationship Between Surface Electromyographic Activity and Torque Production of the Infraspinatus Muscle in Shoulder Rehabilitation Exercises.
This study was designed to investigate the relationship between surface EMG activity of the infraspinatus and torque production during exercises involving shoulder external rotation (ER). A total of 30 participants (average age = 24.6 y) performed maximum voluntary isometric contraction of ER at 5 points within the range of motion of 3 shoulder exercise positions with concomitant surface EMG recording. As a maximal internally rotated position was approached, maximum ER torque and minimum or near-minimum EMG recruitment were demonstrated. Conversely, at maximally externally rotated positions, EMG activity was greatest ...
Source: Journal of Applied Biomechanics - March 19, 2020 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Trunk-Pelvis Kinematics Variability During Gait and Its Association With Trunk Muscle Endurance in Patients With Chronic Low Back Pain.
Authors: Bagheri R, Ebrahimi Takamjani I, Pourahmadi MR, Jannati E, Fazeli SH, Hedayati R, Akbari M Abstract The first purpose was to investigate the trunk muscle endurance, the second aim was to evaluate the trunk-pelvis kinematics during gait, and the third was to evaluate the relationship between trunk-pelvis kinematics and the trunk muscle endurance. Thirty participants (15 nonspecific chronic low back pain [NCLBP] and 15 healthy) were included. The authors first assessed trunk muscle endurance on endurance testing protocols. The authors next measured the trunk-pelvis kinematics during gait using a 3-dimensiona...
Source: Journal of Applied Biomechanics - March 17, 2020 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Lessons Learned.
Authors: Herzog W PMID: 32176863 [PubMed - as supplied by publisher] (Source: Journal of Applied Biomechanics)
Source: Journal of Applied Biomechanics - March 17, 2020 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Lessons Learned: How to Organize Your Laboratory Meetings.
Authors: Stergiou N PMID: 32163921 [PubMed - as supplied by publisher] (Source: Journal of Applied Biomechanics)
Source: Journal of Applied Biomechanics - March 13, 2020 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Effect of Running Speed and Midsole Type on Foot Loading in Heel-Toe Running.
Authors: Peng P, Ding S, Wang Z, Zhang Y, Pan J Abstract The purpose of this study was to explore the immediate effects of running speed and midsole type on foot loading during heel-toe running. Fifteen healthy male college students were required to complete 3 running trials on an indoor 45-m tartan runway at 4 different speeds (3, 4, 5, and 6 m/s) using 2 different running footwear types (engineering thermoplastic polyurethane elastomer, polyurethane elastomer; and ethylene vinyl acetate, vinyl acetate). The ground reaction force and plantar pressure data were quantified. Significant speed effects were detect...
Source: Journal of Applied Biomechanics - March 7, 2020 Category: Sports Medicine Tags: J Appl Biomech Source Type: research

Differences in Rotational Kinetics and Kinematics for Professional Baseball Pitchers With Higher Versus Lower Pitch Velocities.
Authors: Luera MJ, Dowling B, Muddle TWD, Jenkins NDM Abstract Pitch velocity (PV) is important for pitching success, and the pelvis and trunk likely influence pitch performance. The purposes of this study were to examine the differences in pelvis and trunk kinetics and kinematics in professional baseball pitchers who throw at lower versus higher velocities (HVPs) and to examine the relationships among pelvis and trunk kinetics and kinematics and PV during each phase of the pitch delivery. The pitch velocity, pelvis and trunk peak angular velocities, kinetic energies and torques, and elbow and shoulder loads were c...
Source: Journal of Applied Biomechanics - March 7, 2020 Category: Sports Medicine Tags: J Appl Biomech Source Type: research