Research Topics
| Samuel R WardSummaryAffiliation: University of California Country: USA Publications
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Detail Information
Publications
The influence of patella alta on patellofemoral joint stress during normal and fast walkingSamuel R Ward
Musculoskeletal Biomechanics Research Laboratory, Department of Biokinesiology and Physical Therapy, University of Southern California, Los Angeles, CA, USA
Clin Biomech (Bristol, Avon) 19:1040-7. 2004..To determine if persons with patella alta exhibit elevated patellofemoral joint stress compared to pain-free controls during normal and fast walking speeds...
The architectural design of the gluteal muscle group: implications for movement and rehabilitationSamuel R Ward
Department of Radiology, University of California San Diego, La Jolla, CA 92124, USA
J Orthop Sports Phys Ther 40:95-102. 2010..These data demonstrate the architectural and functional specialization of the hip muscles, and highlight the importance of muscle physiology and joint mechanics when evaluating and treating musculoskeletal disorders...- Plasticity of muscle architecture after supraspinatus tearsSamuel R Ward
Department of Radiology, University of California and Veterans Administration Medical Centers, San Diego, CA, USA
J Orthop Sports Phys Ther 40:729-35. 2010..Controlled laboratory study... - Patella alta: association with patellofemoral alignment and changes in contact area during weight-bearingSamuel R Ward
Musculoskeletal Biomechanics Research Laboratory, Department of Biokinesiology and Physical Therapy, University of Southern California, Los Angeles, CA 90089, USA
J Bone Joint Surg Am 89:1749-55. 2007..We compared patellofemoral joint alignment and contact area in subjects who had patella alta with subjects who had normal patellar position, to determine the effect of high vertical patellar positions on knee extensor mechanics... - Influence of patella alta on knee extensor mechanicsSamuel R Ward
Musculoskeletal Biomechanics Research Laboratory, Department of Biokinesiology and Physical Therapy, University of Southern California, Los Angeles, CA, USA
J Biomech 38:2415-22. 2005..Therefore, persons with patella alta may experience less patellofemoral joint reaction force to overcome the same knee flexion moment in the range of 0 degrees -60 degrees of knee flexion... 
A novel muscle biopsy clamp yields accurate in vivo sarcomere length valuesSamuel R Ward
Department of Orthopaedic Surgery, University of California and Veterans Administration Medical Center, San Diego, CA 92161, USA
J Biomech 42:193-6. 2009....- Effect of bracing on patellofemoral joint stress while ascending and descending stairsChristopher M Powers
Department of Biokinesiology and Physical Therapy, University of Southern California, Los Angeles, CA 90089 9006, USA
Clin J Sport Med 14:206-14. 2004..To test the hypothesis that individuals who respond favorably to bracing will exhibit decreased patellofemoral joint stress during stair ambulation... - Psoas muscle architectural design, in vivo sarcomere length range, and passive tensile properties support its role as a lumbar spine stabilizerGilad J Regev
Department of Orthopaedic Surgery, University of California Medical Center, San Diego, CA, USA
Spine (Phila Pa 1976) 36:E1666-74. 2011..Controlled laboratory and cross-sectional study designs... - Asynchronous muscle and tendon adaptation after surgical tensioning proceduresMitsuhiko Takahashi
Department of Orthopaedic Surgery, University of California and Veterans Affairs Medical Center, San Diego, 3350 La Jolla Village Drive, San Diego, CA 92161, USA
J Bone Joint Surg Am 92:664-74. 2010..This study was performed to evaluate muscle-tendon-unit adaptation to tendon transfer surgery in an animal model... - The effect of bracing on patellofemoral joint stress during free and fast walkingChristopher M Powers
Department of Biokinesiology and Physical Therapy, University of Southern California, Los Angeles, California 90089-9006, USA
Am J Sports Med 32:224-31. 2004..Clinical Relevance: The results of this study suggest a possible mechanism by which bracing may be effective in reducing PFP and provides experimental support for the use of this treatment method... - Passive mechanical properties and related proteins change with botulinum neurotoxin A injection of normal skeletal muscleBryan E Thacker
Department of Bioengineering, University of California and Veterans Administration Medical Centers San Diego, La Jolla, California, USA
J Orthop Res 30:497-502. 2012..Injection of botulinum neurotoxin A produces an effect on the passive mechanical properties of normal muscle that is opposite to the changes observed in spastic muscles... - ISSLS prize winner: Adaptations to the multifidus muscle in response to experimentally induced intervertebral disc degenerationStephen H M Brown
Department of Orthopaedic Surgery, University of California San Diego, San Diego, CA 92093, USA
Spine (Phila Pa 1976) 36:1728-36. 2011..Basic science study of the rabbit multifidus muscle response to intervertebral disc degeneration... - Whole muscle length-tension relationships are accurately modeled as scaled sarcomeres in rabbit hindlimb musclesTaylor M Winters
Department of Bioengineering, University of California and Veterans Administration Medical Centers 3350 La Jolla Village Drive, San Diego, CA 92161, USA
J Biomech 44:109-15. 2011.... - Mechanical strength of the side-to-side versus Pulvertaft weave tendon repairStephen H M Brown
Departments of Orthopaedic Surgery and Radiology, University of California, San Diego, San Diego, CA, USA
J Hand Surg Am 35:540-5. 2010..This study was designed to test the strength and stiffness of the SS technique against a variation of the Pulvertaft (PT) repair technique... - Theoretical predictions of the effects of force transmission by desmin on intersarcomere dynamicsGretchen A Meyer
Department of Bioengineering, University of California, San Diego, California, USA
Biophys J 98:258-66. 2010.... - Regional Myosin heavy chain distribution in selected paraspinal musclesGilad J Regev
Department of Orthopaedic Surgery, University of California, San Diego, La Jolla, CA 92093, USA
Spine (Phila Pa 1976) 35:1265-70. 2010..Cross-sectional study with repeated measures design... - Passive mechanical properties of rat abdominal wall muscles suggest an important role of the extracellular connective tissue matrixStephen H M Brown
Department of Orthopaedic Surgery, University of California San Diego, Research Service VA San Diego Healthcare System San Diego, California, USA
J Orthop Res 30:1321-6. 2012..Titin molecular mass was significantly less in TrA compared to each of the other three muscles (p < 0.0009), but this difference did not correspond to hypothesized differences in stiffness... - Correlation between isometric force and intramuscular pressure in rabbit tibialis anterior muscle with an intact anterior compartmentTaylor M Winters
Department of Bioengineering, University of California San Diego, San Diego, California, USA
Muscle Nerve 40:79-85. 2009..98 +/- 0.01 for the active descending limb. These data demonstrate that muscle force and IMP are fairly well correlated under isometric conditions and that this relationship is not improved by measuring IMP in an intact environment... - The effect of bracing on patella alignment and patellofemoral joint contact areaChristopher M Powers
Department of Biokinesiology and Physical Therapy, University of Southern California, Los Angeles, CA 90036, USA
Med Sci Sports Exerc 36:1226-32. 2004..To examine the influence of two patellofemoral braces on pain response, patellar alignment, and patellofemoral joint contact area in persons with patellofemoral pain... - Patellofemoral kinematics during weight-bearing and non-weight-bearing knee extension in persons with lateral subluxation of the patella: a preliminary studyChristopher M Powers
Musculoskeletal Biomechanics Research Laboratory, Department of Biokinesiology and Physical Therapy, University of Southem California, Los Angles, CA, USA
J Orthop Sports Phys Ther 33:677-85. 2003..Single-group, repeated-measures design... - Muscle excursion does not correlate with increased serial sarcomere number after muscle adaptation to stretched tendon transferMitsuhiko Takahashi
Orthopaedic Surgery, University of California and Research Service, VA San Diego Healthcare System, San Diego, CA, USA
J Orthop Res 30:1774-80. 2012..These data have significant implications for examining muscle physiological properties under surgical interventions... - Architectural analysis and intraoperative measurements demonstrate the unique design of the multifidus muscle for lumbar spine stabilitySamuel R Ward
Department of Orthopaedic Surgery, V A Medical Center and University of California at San Diego, 3350 La Jolla Village Drive, San Diego, CA 92161, USA
J Bone Joint Surg Am 91:176-85. 2009.... - Dorsal transfer of the brachioradialis to the flexor pollicis longus enables simultaneous powering of key pinch and forearm pronationSamuel R Ward
Department of Radiology, University of California and Veterans Administration San Diego, San Diego, CA 92161, USA
J Hand Surg [Am] 31:993-7. 2006..As result a larger patient population may benefit from the BR-to-FPL reconstructive procedure... - Hamstring contractures in children with spastic cerebral palsy result from a stiffer extracellular matrix and increased in vivo sarcomere lengthLucas R Smith
Departments of Bioengineering, University of California, San Diego, CA, USA
J Physiol 589:2625-39. 2011.... - Mechanical feasibility of immediate mobilization of the brachioradialis muscle after tendon transferJan Friden
Department of Orthopaedic Surgery, University of California San Diego, San Diego, CA, USA
J Hand Surg Am 35:1473-8. 2010..The purpose of this study was to measure the BR-FPL tendon tension across a range of wrist and elbow joint angles to determine whether joint motion could cause repair rupture... - Assessment of patellofemoral relationships using kinematic MRI: comparison between qualitative and quantitative methodsSamuel R Ward
Musculoskeletal Biomechanics Research Laboratory, Department of Biokinesiology and Physical Therapy, University of Southern California, Los Angeles 90089-4500, USA
J Magn Reson Imaging 16:69-74. 2002..That is, quantitative measurements are based on the use of osseous landmarks, while the qualitative assessments tend to rely on a description of patellofemoral relationships based on joint surfaces... - Intraoperative single-site sarcomere length measurement accurately reflects whole-muscle sarcomere length in the rabbitMitsuhiko Takahashi
Department of Orthopaedic Surgery, University of California and Veterans Affairs Medical Centers, San Diego, CA 92161, USA
J Hand Surg Am 32:612-7. 2007..To compare single-site intraoperative sarcomere length values with sarcomere lengths measured from systematic sampling of the entire transferred muscle... - Human skeletal muscle biochemical diversityTimothy F Tirrell
Department of Orthopaedic Surgery, University of California San Diego, La Jolla, CA 92093, USA
J Exp Biol 215:2551-9. 2012..These trends suggest that distal muscles should have higher passive tension than proximal ones, and that titin size variability may potentially act to 'tune' the protein's mechanotransduction capability... - Quantification of patellofemoral joint contact area using magnetic resonance imagingJacklyn Heino Brechter
Department of Physical Therapy, Chapman University, Orange, CA, USA
Magn Reson Imaging 21:955-9. 2003..Developing a non-invasive technique to evaluate contact area will assist researchers and/or clinicians in obtaining patient-specific contact area data to be used in biomechanical analyses and clinical decision making... - Relationship between muscle stress and intramuscular pressure during dynamic muscle contractionsSamuel R Ward
Department of Radiology, University of California and Veterans Administration Medical Centers, San Diego, California 92161, USA
Muscle Nerve 36:313-9. 2007..They also illustrate the need to control transducer movement if muscle stress is to be inferred from IMP measurements such as might be desired during clinical gait testing... - Rotator cuff muscle architecture: implications for glenohumeral stabilitySamuel R Ward
Department of Orthopaedics and Bioengineering, University of California and Veterans Administration Medical Centers, San Diego, 92161, USA
Clin Orthop Relat Res 448:157-63. 2006..During surgery relatively small changes to rotator cuff muscle length may result in relatively large changes in shoulder function... - High stiffness of human digital flexor tendons is suited for precise finger positional controlSamuel R Ward
Department of Radiology, Biomedical Sciences Graduate Group, University of California, San Diego, California 92093, USA
J Neurophysiol 96:2815-8. 2006..Thus the high stiffness of the digital flexor tendons suits them well for fine positional control and would render their muscle spindles quite sensitive to length perturbations at the fingertips... - Scaling of muscle architecture and fiber types in the rat hindlimbCarolyn M Eng
Department of Orthopaedic Surgery, University of California and Veterans Administration Medical Centers, San Diego, CA, USA
J Exp Biol 211:2336-45. 2008..This implies that functional demands placed on muscles across species should be examined on the single muscle level... - Sarcomere length measurement permits high resolution normalization of muscle fiber length in architectural studiesAmanda Felder
Department of Orthopaedic Surgery, University of California, San Diego, CA 92161, USA
J Exp Biol 208:3275-9. 2005..We thus conclude that the use of sarcomere length normalization in architectural studies permits resolution of fiber length variations of 15% and may even be effective at resolving 10% fiber length variations... - Skeletal muscle design to meet functional demandsRichard L Lieber
Department of Orthopaedic Surgery, University of California San Diego, San Diego, CA 92121, USA
Philos Trans R Soc Lond B Biol Sci 366:1466-76. 2011..Taken together, the case is made that muscles can be fine-tuned to perform specific tasks that require actuators with a wide range of properties... - Density and hydration of fresh and fixed human skeletal muscleSamuel R Ward
Departments of Orthopaedic Surgery and Bioengineering, Veterans Affairs Medical Center and University of California-San Diego, 3350 La Jolla Village Drive, La Jolla, CA, USA
J Biomech 38:2317-20. 2005..112+/-0.006 g/cm(3) in 4% formaldehyde-fixed muscle and 1.055+/-0.006 g/cm(3) in 37% formaldehyde-fixed muscle. These results indicate that the use of inappropriate hydration times or density values can produce PCSA errors of 5-10%... - Pronator teres is an appropriate donor muscle for restoration of wrist and thumb extensionGeoffrey D Abrams
Department of Orthopaedics, University of California, San Diego, CA 92093-9151, USA
J Hand Surg [Am] 30:1068-73. 2005..These data suggest that releasing the ulnar head of the PT before transfer may result in larger excursions of this important motor in tendon transfer surgery... - Architectural and morphological assessment of rat abdominal wall muscles: comparison for use as a human modelStephen H M Brown
Department of Orthopaedic Surgery, University of California San Diego and VA Medical Center, San Diego, CA 92093 0863, USA
J Anat 217:196-202. 2010.... - Are current measurements of lower extremity muscle architecture accurate?Samuel R Ward
Department of Radiology, University of California and Veterans Administration Medical Centers, San Diego, CA, USA
Clin Orthop Relat Res 467:1074-82. 2009..These high-resolution data will facilitate the development of more accurate musculoskeletal models and challenge existing theories of muscle design; we believe they will aid in surgical decision making... - Muscle adaptation by serial sarcomere addition 1 year after femoral lengtheningJennette L Boakes
Department of Orthopaedic Surgery, Shriners Hospital for Children, Sacramento, CA, USA
Clin Orthop Relat Res 456:250-3. 2007..This direct measurement of fascicle length and sarcomere length confirms sarcomerogenesis in human skeletal muscle secondary to chronic length change, and shows the capacity of human muscle to adapt to length changes... - Muscle geometry affects accuracy of forearm volume determination by magnetic resonance imaging (MRI)Carolyn M Eng
Department of Orthopaedic Surgery, University of California, San Diego, CA, USA
J Biomech 40:3261-6. 2007.... - Quantitative analysis of neonatal skeletal muscle functional improvement in the mouseDavid S Gokhin
Department of Bioengineering, University of California San Diego, La Jolla, CA 92093, USA
J Exp Biol 211:837-43. 2008..These data provide the first specific structural basis for increases in muscle tension development during growth. Therefore, models of muscle growth must be modified to include an intrinsic quality enhancement component... - Passive mechanical properties of the lumbar multifidus muscle support its role as a stabilizerSamuel R Ward
Department of Orthopaedic Surgery, University of California and Veterans Administration Medical Centers, San Diego, CA 92161, USA
J Biomech 42:1384-9. 2009..These data will provide key input variables for biomechanical modeling of normal and pathologic lumbar spine function and direct future work in biomechanical testing in these important muscles... - Sample size considerations in human muscle architecture studiesLori J Tuttle
Department of Orthopaedic Surgery, University of California San Diego, San Diego, California, USA
Muscle Nerve 45:742-5. 2012..This report is a meta-analysis of the human muscle architecture literature that analyzes the number of muscles, number of subjects, and muscle fiber length coefficient of variation (CV) by body region... - Capsular ligaments of the hip: anatomic, histologic, and positional study in cadaveric specimens with MR arthrographyFelipe V Wagner
Department of Radiology, University of California San Diego, San Diego, CA, USA
Radiology 263:189-98. 2012..To demonstrate the anatomy of the capsular ligaments of the hip by using magnetic resonance (MR) arthrography... - The use of neural networks and texture analysis for rapid objective selection of regions of interest in cytoskeletal imagesAmanda D Felder Derkacs
Department of Bioengineering, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093 0863, USA
Microsc Microanal 18:115-22. 2012..We found that this method was over 300 times faster than manual classification and that it permitted objective and accurate classification of image regions... - Functional recovery of muscles after minimally invasive total hip arthroplastySamuel R Ward
Department of Radiology, University of California San Diego, San Diego, California, USA
Instr Course Lect 57:249-54. 2008..This finding suggests that the amount of muscle, or the particular muscle cut, does not have a significant effect on the recovery of postoperative gait function... - Novel transcriptional profile in wrist muscles from cerebral palsy patientsLucas R Smith
Department of Bioengineering, University of California San Diego, La Jolla, California, USA
BMC Med Genomics 2:44. 2009..Further research is required to understand the mechanism of muscle adaptation to this upper motor neuron lesion that could lead to the development of innovative therapies... - Concurrent criterion-related validity and reliability of a clinical device used to assess lateral patellar displacementSusumu Ota
Program in Physical and Occupational Therapy, Nagoya University Graduate School of Medicine, Aichi, Japan
J Orthop Sports Phys Ther 36:645-52. 2006..86). Excellent intratester (ICC, 0.96 and 0.97) and intertester reliability (ICC, 0.92) were demonstrated. CONCLUSION: Our results suggest that reasonable estimations of lateral patellar displacement can be obtained using the PFA... - Increased efficacy and decreased systemic-effects of botulinum toxin A injection after active or passive muscle manipulationViviane B Minamoto
Department of Physical Therapy, Piracicaba Methodist University, Piracicaba, Brazil
Dev Med Child Neurol 49:907-14. 2007..These data demonstrate that both neuromuscular activity (seen in the ISO group) and muscle movement (seen in the PS group) increased the efficacy of BTX-A and decreased the systemic side effects... - Postoperative pain management following total knee arthroplasty: a randomized comparison of continuous epidural versus femoral nerve infusionWilliam T Long
The Arthritis Institute, Inglewood, CA 90301, USA
J Knee Surg 19:137-43. 2006 - Passive muscle-tendon amplitude may not reflect skeletal muscle functional excursionJan Friden
Department of Hand Surgery, Sahlgrenska University Hospital, Goteborg, Sweden
J Hand Surg Am 31:1105-10. 2006..To quantify the gain in muscle mobility with progressive release of surrounding connective-tissue structures and to compare this property with the known architecture of each muscle...