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Journal of Applied Biomechanics

Christopher D Ramos, Melvin Ramey, Rand R Wilcox, Jill L McNitt-Gray
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 variables (α = 0...
September 12, 2018: Journal of Applied Biomechanics
Alif Laila Tisha, Ashley Allison Armstrong, Amy Wagoner Johnson, Citlali Lopez-Ortiz
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...
September 12, 2018: Journal of Applied Biomechanics
Wataru Kawakami, Makoto Takahashi, Yoshitaka Iwamoto, Koichi Shinakoda
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 recruited in this study...
September 12, 2018: Journal of Applied Biomechanics
Katherine L Hsieh, Yaejin Moon, Vignesh Ramkrishnan, Rama Ratnam, Jacob J Sosnoff
Virtual time to contact (VTC) is a measure of postural stability that estimates the virtual time it would take to reach an individual's stability boundary. 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...
September 12, 2018: Journal of Applied Biomechanics
Ricardo Pires, Thays Falcari, Alexandre B Campo, Bárbara C Pulcineli, Joseph Hamill, Ulysses F Ervilha
The present study aimed to use a Support Vector Machine (SVM) algorithm to identify and classify shod and barefoot running as well as rearfoot and forefoot landings. Ten habitually shod runners ran at self-selected speed. Thigh and leg muscle surface electromyography (EMG) were recorded. Discrete Wavelet transformation (DWT) and Fast Fourier transformation (FFT) were used for the assembly of vectors for training and classification of a SVM. Using the FFT coefficients for the gastrocnemius and tibialis anterior muscles presented the best results for differentiating between rearfoot/forefoot running in the window before foot-floor contact possibly due to these muscles' critical role in determining which part of the foot will first touch the floor...
September 12, 2018: Journal of Applied Biomechanics
Leigh J Allin, Maury A Nussbaum, Michael L Madigan
Task-specific balance training is an approach to fall prevention that has the potential to reduce the number of slip-induced falls. However, a limitation of current task-specific training methods is that they require non-trivial financial and/or equipment resources. This pilot study evaluated the efficacy of two low-cost, low-tech methods for slip recovery training in improving balance recovery ability. The two methods were: 1) repeated unexpected slip training (UST), which involved repeated unexpected slips while walking (similar to current methods of task-specific slip recovery training); and 2) volitional slip-recovery training (VST), which involved practicing a slip recovery response after volitionally stepping to induce a slip-like perturbation...
August 6, 2018: Journal of Applied Biomechanics
Stephen M Glass, Alessandro Napoli, Elizabeth D Thompson, Iyad Obeid, Carole A Tucker
The Balance Error Scoring System (BESS) is a human-scored, field-based balance test used in cases of suspected concussion. Recently developed instrumented alternatives to human scoring carry substantial advantages over traditional testing, but thus far report relatively abstract outcomes which may not be useful to clinicians or coaches. In contrast, the Automated Assessment of Postural Stability (AAPS) is a computerized system that tabulates error events in accordance with the original description of the BESS...
August 6, 2018: Journal of Applied Biomechanics
Travis J Peterson, Jill L McNitt-Gray
Golf shots off uneven terrain often require modifications in address position to complete the swing successfully. This study aimed to determine how golf players coordinate the legs to regulate linear and angular impulse (about an axis passing vertically through the center of mass) while modifying the lower extremity address position during the swing. Nine highly skilled golf players performed swings with a 6-iron under the Normal, Rear Leg Up and Target Leg Up conditions. Components of linear and angular impulse generated by the rear and target legs (resultant horizontal reaction force, resultant horizontal reaction force angle, and moment arm) were quantified and compared across the group and within a player (α = ...
August 6, 2018: Journal of Applied Biomechanics
Srinidhi Bellamkonda, Samantha J Woodward, Eamon Campolettano, Ryan Gellner, Mireille E Kelley, Derek A Jones, Amaris Genemaras, Jonathan G Beckwith, Richard M Greenwald, Arthur C Maerlender, Steven Rowson, Stefan M Duma, Jillian E Urban, Joel D Stitzel, Joseph J Crisco
This study aimed to compare head impact exposures between practices and games in football players ages 9 to 14 years, who account for approximately 70% of all football players in the United States. Over a period of 2 seasons, 136 players were enrolled from 3 youth programs, and 49,847 head impacts were recorded from 345 practices and 137 games. During the study, individual players sustained a median of 211 impacts per season, with a maximum of 1226 impacts. Players sustained 50th (95th) percentile peak linear acceleration of 18...
July 26, 2018: Journal of Applied Biomechanics
Gustavo Ramos Dalla Bernardina, Tony Monnet, Heber Teixeira Pinto, Ricardo Machado Leite de Barros, Pietro Cerveri, Amanda Piaia Silvatti
The aim of this study was to assess the precision and accuracy of an Action Sport Camera (ASC) system (4 GoPro Hero3+ Black) by comparison with a commercial motion capture (MOCAP) system (4 ViconMX40). Both systems were calibrated using the MOCAP protocol and the 3D markers coordinates of a T-shaped tool were reconstructed, concurrently. The 3D precision was evaluated by the differences in the reconstructed position using a Bland-Altman test, while accuracy was assessed by a rigid bar test (Wilcoxon rank sum)...
July 10, 2018: Journal of Applied Biomechanics
John D McCamley, Eric L Cutler, Kendra K Schmid, Shane R Wurdeman, Jason M Johanning, Iraklis I Pipinos, Sara A Myers
Patients with peripheral artery disease (PAD) experience significant leg dysfunction. The effects of PAD on gait include shortened steps, slower walking velocity, and altered gait kinematics and kinetics, which may confound joint torques and power measurements. Spatiotemporal parameters, joint torques and powers were calculated and compared between 20 patients with PAD and 20 healthy controls using independent t-tests. Separate ANCOVA models were used to evaluate group differences after independently adjusting for gait velocity, stride length and step width...
July 10, 2018: Journal of Applied Biomechanics
Katie A Conway, Randall G Bissette, Jason R Franz
Aging and many gait pathologies are characterized by reduced propulsive forces and ankle moment and power generation during trailing leg push-off in walking. Despite those changes, we posit that many individuals retain an underutilized reserve for enhancing push-off intensity during walking that may be missed using conventional dynamometry. By using a maximum ramped impeding force protocol and maximum speed walking, we gained mechanistic insight into the factors that govern push-off intensity and the available capacity thereof during walking in young subjects...
July 10, 2018: Journal of Applied Biomechanics
Mary Emily Littrell, Young-Hui Chang, Brian P Selgrade
Clinically, measuring gait kinematics and ground reaction force (GRF) is useful to determine the effectiveness of treatment. However, it is inconvenient and expensive to maintain a laboratory-grade gait analysis system in most clinics. The purpose of this study was to validate a Wii Balance Board, Kinovea motion-tracking software, and a video camera as a portable, low-cost, overground gait analysis system. We validated this low-cost system against a multi-camera Vicon system and AMTI force platform. After validation trials with known weights and angles, five subjects walked across an instrumented walkway multiple times (n=8/subject)...
July 10, 2018: Journal of Applied Biomechanics
Michelle R Tanel, Tyler B Weaver, Andrew C Laing
While the literature has characterized balance control during quasi-static and/or dynamic tasks, comparatively few studies have examined relationships across paradigms. This study investigated whether quiet-stance postural steadiness metrics were associated with reactive control parameters (during both stepping and restabilisation phases) following a lean-and-release perturbation. Forty older adults participated. Postural steadiness (centre of pressure range, root mean square, velocity, and frequency) was evaluated in 'feet together' and 'tandem stance' positions...
July 10, 2018: Journal of Applied Biomechanics
Moataz Eltoukhy, Christopher Kuenze, Jeonghoon Oh, Eryn Apanovitch, Lauren Butler, Joseph F Signorile
Anterior cruciate ligament (ACL) injury is one of the most common knee injuries among adolescent athletes. Majority of the ACL injuries occur due to pivoting, sudden deceleration and direction change without contact with any player. Preventive interventions can reduce risks of the ACL injury, thus developing a clinician friendly biomechanical assessment tool to identify athletes with such risk factors is crucial. In this study, we investigated the concurrent validity of a commercially-available depth sensor, Microsoft Kinect, as a cost-effective alternative to the gold standard three-dimensional motion analysis systems in non-contact ACL screening for adolescent athletes during side-cut maneuvers...
July 10, 2018: Journal of Applied Biomechanics
Hiroaki Hobara, Sakiko Saito, Satoru Hashizume, Hiroyuki Sakata, Yoshiyuki Kobayashi
To understand the step characteristics during sprinting in lower-extremity amputees using running-specific prosthesis, each athlete should be investigated individually. Theoretically, sprint performance in a 100-m sprint is determined by both step frequency and step length. The aim of the present study was to investigate how step frequency and step length correlate with sprinting performance in elite unilateral transtibial amputees. By using publicly available Internet broadcasts, we analyzed 88 races from seven unilateral transtibial amputees...
July 10, 2018: Journal of Applied Biomechanics
Rachel L Wright, Joseph W Bevins, David Pratt, Catherine M Sackley, Alan M Wing
Asymmetry in weight-bearing is a common feature in post-stroke hemiparesis, and is related to temporal asymmetry during walking. The aim of this study was to investigate the effect of an auditory cue for stepping in place on measures of temporal and weight-bearing asymmetry. Ten community-dwelling adults (four female) with chronic post-stroke hemiparesis performed 5 un-cued stepping trials and 5 stepping trials cued by an auditory metronome cue. A Vicon system was used to collect full body kinematic trajectories...
July 10, 2018: Journal of Applied Biomechanics
Anamaria Laudet Silva Mangubat, Janet Hanwen Zhang, Zoe Yau-Shan Chan, Aislinn Joan MacPhail, Ivan Pui-Hung Au, Roy Tsz-Hei Cheung
A stable gaze is necessary to optimize visual conditions during running. Head accelerations generally remain stable when looking in front, however it is unclear if this response is similar when the head is turned sideways, and whether other adaptive strategies are present to maintain this stability. The purpose of this study, therefore, was to examine whether runners maintained stable head accelerations while gazing at fixed targets in front and to their sides. We collected biomechanical data from thirteen runners as they directed their gaze to visual targets located in front, 45-degree and 90-degree to the sides at a random sequence...
July 10, 2018: Journal of Applied Biomechanics
Saud F Alsubaie, Susan L Whitney, Joseph M Furman, Gregory F Marchetti, Kathleen H Sienko, Patrick J Sparto
The reliability of balance exercises performance in experimental and clinical studies has typically been confined to a small set of exercises. In order to advance the field of assessing balance exercise intensity, establishing the reliability of performance during a more diverse array of exercises should be undertaken. The purpose of this study was to investigate the test-retest reliability of postural sway produced during performance of 24 different balance tasks, and to evaluate the reliability of different measures of postural sway...
July 10, 2018: Journal of Applied Biomechanics
Rand Wilcox, Travis J Peterson, Jill L McNitt-Gray
The paper reviews advances and insights relevant to comparing groups when the sample sizes are small. There are conditions under which conventional, routinely used techniques are satisfactory. But major insights regarding outliers, skewed distributions, and unequal variances (heteroscedasticity) make it clear that under general conditions they provide poor control over the type I error probability and can have relatively poor power. In practical terms, important differences among groups can be missed and poorly characterized...
August 1, 2018: Journal of Applied Biomechanics
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