Open Access Publications

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Open access publications by faculty, staff, postdocs, and graduate students from the Biomechanics & Movement Science Program.

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Baseline predictors of treatment gains in peak propulsive force in individuals poststroke
(Biomed Central Ltd, 1/15/16) Hsiao,HaoYuan; Higginson,Jill S.; Binder-Macleod,Stuart A.; HaoYuan Hsiao, Jill S. Higginson, Stuart A. Binder-Macleod; Higginson, Jill Startzell; Binder-Macleod, Stuart
Background: Current rehabilitation for individuals poststroke focuses on increasing walking speed because it is an indicator of community walking ability and quality of life. Propulsive force generated from the paretic limb is critical to walking speed and may reflect actual neural recovery that restores the affected neural systems. A wide variation across individuals in the improvements in paretic propulsive force was observed following an intervention that targeted paretic propulsive force. This study aimed to determine if specific baseline characteristics can be used to predict patients who would respond to the intervention. Methods: Participants (N = 19) with chronic poststroke hemiparesis walked at their self-selected and maximal walking speeds on a treadmill before and after a 12-week gait training program. Propulsive forces from the paretic limb were analyzed. Pearson correlation coefficient was used to determine the relationships between (1) treatment gains in walking speed and propulsive force following intervention, and (2) treatment gains in propulsive force and baseline propulsive forces. Results: Treatment gains in self-selected walking speed were correlated to treatment gains in paretic propulsive force following intervention. In addition, changes in paretic propulsive force between self-selected and maximal walking speeds at baseline were strongly correlated to treatment gains in paretic propulsive force. Conclusions: The capacity to modulate paretic propulsive force, rather than the absolute propulsive force during self-selected or maximal walking speed, predicted treatment gains in propulsive force following the intervention. Findings from this research could help to inform clinicians and researchers to target the appropriate patient population for rehabilitation interventions.
Mechanisms to increase propulsive force for individuals poststroke
(BioMed Central Ltd., 2015-04-18) Hsiao, HaoYuan; Knarr, Brian A.; Higginson, Jill S.; Binder-Macleod, Stuart A.; HaoYuan Hsiao, Brian A Knarr, Jill S Higginson3 and Stuart A Binder-Macleod4; Hsiao, HaoYuan; Higginson, Jill S.; Binder-Macleod, Stuart A.
BACKGROUND: Propulsive force generation is critical to walking speed. Trialing limb angle and ankle moment are major contributors to increases in propulsive force during gait. For able-bodied individuals, trailing limb angle contributes twice as much as ankle moment to increases in propulsive force during speed modulation. The aim of this study was to quantify the relative contribution of ankle moment and trailing limb angle to increases in propulsive force for individuals poststroke. METHODS: A biomechanical-based model previously developed for able-bodied individuals was evaluated and enhanced for individuals poststroke. Gait analysis was performed as subjects (N = 24) with chronic poststroke hemiparesis walked at their self-selected and fast walking speeds on a treadmill. RESULTS: Both trailing limb angle and ankle moment increased during speed modulation. In the paretic limb, the contribution from trailing limb angle versus ankle moment to increases in propulsive force is 74% and 17%. In the non-paretic limb, the contribution from trailing limb angle versus ankle moment to increases in propulsive force is 67% and 22%. CONCLUSIONS: Individuals poststroke increase propulsive force mainly by changing trailing limb angle in both the paretic and non-paretic limbs. This strategy may contribute to the inefficiency in poststroke walking patterns. Future work is needed to examine whether these characteristics can be modified via intervention.
Atypical object exploration in infants at-risk for autism during the first year of life
(Frontiers Media S.A., 2015-06-16) Kaur, Maninderjit; Srinivasan, Sudha M.; Bhat, Anjana N.; Kaur, Maninderjit; Srinivasan, Sudha M.; Bhat, Anjana N.
Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder usually diagnosed by the end of the second year of life. Early signs of ASD within the first year of life are still unclear. The main purpose of the present study was to compare object exploration skills between infants at-risk for ASD and typically developing (TD) infants to determine early markers for autism within the first year of life. Sixteen at-risk infants and 16 TD infants were longitudinally followed from 6 to 15 months of age during an object exploration task involving three objects with distinct size, shape, and texture, i.e., a long rattle, a rigid circular ball, and a soft circular koosh ball. All sessions were videotaped for coding of manual exploration (grasping and dropping), oral exploration (mouthing), and visual exploration (looking). We also obtained follow-up outcomes using various developmental questionnaires at 18 months and email follow-up on developmental delays/ASD diagnosis after the infants’ second birthdays. Our results showed object-based differences in exploration patterns that extended across both groups. We also noticed context-dependent group differences for various exploratory behaviors across objects and ages. Specifically, at 6 months, at-risk infants showed less grasping of the rigid ball as well as less mouthing and greater looking at the rattle compared to TD infants. At 9 and 12 months, at-risk infants demonstrated significantly lower levels of purposeful dropping of all objects and greater looking at the rattle. Lastly, at 15 months, at-risk infants showed persistent mouthing of the rigid ball and rattle compared to TD infants. In addition, 10 out of 16 at-risk infants developed various motor, social, and language delays or ASD diagnosis at follow-up. Taken together, early context-dependent delays/abnormalities in object exploration could be markers for future developmental delays in infants at-risk for autism. Moreover, promoting early object experiences through socially embedded, free and structured play could have significant implications for multisystem development including perceptuo-motor, social communication, and cognitive development in at-risk infants.
Baseline predictors of treatment gains in peak propulsive force in individuals poststroke
(BioMed Central, 2016-01-15) Hsiao, HaoYuan; Higginson, Jill S.; Binder-Macleod, Stuart A.; HaoYuan Hsiao, Jill S. Higginson and Stuart A. Binder-Macleod; Hsiao, HaoYuan; Higginson, Jill S.; Binder-Macleod, Stuart A.
BACKGROUND: Current rehabilitation for individuals poststroke focuses on increasing walking speed because it is an indicator of community walking ability and quality of life. Propulsive force generated from the paretic limb is critical to walking speed and may reflect actual neural recovery that restores the affected neural systems. A wide variation across individuals in the improvements in paretic propulsive force was observed following an intervention that targeted paretic propulsive force. This study aimed to determine if specific baseline characteristics can be used to predict patients who would respond to the intervention. METHODS: Participants (N = 19) with chronic poststroke hemiparesis walked at their self-selected and maximal walking speeds on a treadmill before and after a 12-week gait training program. Propulsive forces from the paretic limb were analyzed. Pearson correlation coefficient was used to determine the relationships between (1) treatment gains in walking speed and propulsive force following intervention, and (2) treatment gains in propulsive force and baseline propulsive forces. RESULTS: Treatment gains in self-selected walking speed were correlated to treatment gains in paretic propulsive force following intervention. In addition, changes in paretic propulsive force between self-selected and maximal walking speeds at baseline were strongly correlated to treatment gains in paretic propulsive force. CONCLUSIONS: The capacity to modulate paretic propulsive force, rather than the absolute propulsive force during self-selected or maximal walking speed, predicted treatment gains in propulsive force following the intervention. Findings from this research could help to inform clinicians and researchers to target the appropriate patient population for rehabilitation interventions.
Control Strategy of Maximum Vertical Jumps: the Preferred Countermovement Depth May Not Be Fully Optimized for Jump Height
(De Gruyter Open, 2016-09-10) Mandic, Radivoj; Knezevic, Olivera M.; Mirkov, Dragan M.; Jaric, Slobodan; Radivoj Mandic, Olivera M. Knezevic, Dragan M. Mirkov, Slobodan Jaric; Jaric, Slobodan
The aim of the present study was to explore the control strategy of maximum countermovement jumps regarding the preferred countermovement depth preceding the concentric jump phase. Elite basketball players and physically active non-athletes were tested on the jumps performed with and without an arm swing, while the countermovement depth was varied within the interval of almost 30 cm around its preferred value. The results consistently revealed 5.1-11.2 cm smaller countermovement depth than the optimum one, but the same difference was more prominent in non-athletes. In addition, although the same differences revealed a marked effect on the recorded force and power output, they reduced jump height for only 0.1-1.2 cm. Therefore, the studied control strategy may not be based solely on the countermovement depth that maximizes jump height. In addition, the comparison of the two groups does not support the concept of a dual-task strategy based on the trade-off between maximizing jump height and minimizing the jumping quickness that should be more prominent in the athletes that routinely need to jump quickly. Further research could explore whether the observed phenomenon is based on other optimization principles, such as the minimization of effort and energy expenditure. Nevertheless, future routine testing procedures should take into account that the control strategy of maximum countermovement jumps is not fully based on maximizing the jump height, while the countermovement depth markedly confound the relationship between the jump height and the assessed force and power output of leg muscles.
Brain Activation in the Prefrontal Cortex during Motor and Cognitive Tasks in Adults
(Scientific Research Publishing, 2016-11-03) Liang, Ling-Yin; Shewokis, Patricia A.; Getchell, Nancy; Ling-Yin Liang, Patricia A. Shewokis, Nancy Getchell; Getchell, Nancy
The prefrontal cortex (PFC) plays an important role in cognitive function, involved in Executive Functions (EFs) such as planning, working memory, and inhibition. Activation in the PFC also occurs during some motor activities. One commonly used tool to assess EF is the Tower of Hanoi, demonstrating sensitivity to PFC dysfunction. However, limited neuroimaging evidence is available to support the contribution of the PFC in the Tower of Hanoi task. In the current study, we use functional near infrared (fNIR) spectroscopy to examine hemodynamic responses associated with neural activity in the PFC in adults as they participate in the Tower of Hanoi task. We compared changes in cerebral oxygenation during resting, a motor task (tapping), and the Tower of Hanoi in 16 neurotypical adults, with measures of relative changes in concentration of oxygenated hemoglobin (Δoxy-Hb) and deoxygenated hemoglobin (Δdeoxy-Hb) taken throughout tasks, as well as total hemoglobin (ΔHbT) and oxygenation (Δoxy). Performance on the Tower of Hanoi was measured by the number of moves used to complete each level and the highest level of successful performance (3, 4, or 5 disks). We found a significant higher value of Δoxy-Hb and Δoxy in dorsolateral PFC (DLPFC) during the Tower of Hanoi as compared to tapping and resting. Significant changes in Δdeoxy-Hb and ΔHbT during the Tower of Hanoi were found in the right DLPFC only. These results support the notion that the Tower of Hanoi task requires higher levels of PFC activity than a similar motor task with low executive function demands.
Muscle Force-Velocity Relationships Observed in Four Different Functional Tests
(DE GRUYTER OPEN LTD, 2017-03-13) Zivkovic, Milena Z.; Djuric, Sasa; Cuk, Ivan; Suzovic, Dejan; Jaric, Slobodan; Milena Z. Zivkovic, Sasa Djuric, Ivan Cuk, Dejan Suzovic, Slobodan Jaric; Jaric, Slobodan
The aims of the present study were to investigate the shape and strength of the force-velocity relationships observed in different functional movement tests and explore the parameters depicting force, velocity and power producing capacities of the tested muscles. Twelve subjects were tested on maximum performance in vertical jumps, cycling, bench press throws, and bench pulls performed against different loads. Thereafter, both the averaged and maximum force and velocity variables recorded from individual trials were used for force-velocity relationship modeling. The observed individual force–velocity relationships were exceptionally strong (median correlation coefficients ranged from r = 0.930 to r = 0.995) and approximately linear independently of the test and variable type. Most of the relationship parameters observed from the averaged and maximum force and velocity variable types were strongly related in all tests (r = 0.789-0.991), except for those in vertical jumps (r = 0.485-0.930). However, the generalizability of the force-velocity relationship parameters depicting maximum force, velocity and power of the tested muscles across different tests was inconsistent and on average moderate. We concluded that the linear force-velocity relationship model based on either maximum or averaged force-velocity data could provide the outcomes depicting force, velocity and power generating capacity of the tested muscles, although such outcomes can only be partially generalized across different muscles.
Knee joint biomechanics during gait improve from 3 to 6 months after anterior cruciate ligament reconstruction
(Journal of Orthopaedic Research, 2022-01-06) Neal, Kelsey; Williams, Jack R.; Alfayyadh, Abdulmajeed; Capin, Jacob J.; Khandha, Ashutosh; Manal, Kurt; Snyder‐Mackler, Lynn; Buchanan, Thomas S.
Gait alterations after anterior cruciate ligament reconstruction (ACLR) are commonly reported and have been linked to posttraumatic osteoarthritis development. While knee gait alterations have been studied at several time points after ACLR, little is known about how these biomechanical variables change earlier than 6 months after surgery, nor is much known about how they differ over the entire stance phase of gait. The purpose of this study was to examine knee gait biomechanical variables over their entire movement pattern through stance at both 3 and 6 months after ACLR and to study the progression of interlimb asymmetry between the two postoperative time points. Thirty-five individuals underwent motion analysis during overground walking 3 (3.2 ± 0.5) and 6 (6.4 ± 0.7) months after ACLR. Knee biomechanical variables were compared between limbs and across time points through 100% of stance using statistical parametric mapping; this included a 2 × 2 (Limb × Time) repeated measures analysis of variance and two-tailed t-tests. Smaller knee joint angles, moments, extensor forces, and medial compartment forces were present in the involved versus uninvolved limb. Interlimb asymmetries were present at both time points but were less prevalent at 6 months. The uninvolved limb's biomechanical variables stayed relatively consistent over time, while the involved limb's trended toward that of the uninvolved limb. Statement of Clinical Significance: Interventions to correct asymmetrical gait patterns after ACLR may need to occur early after surgery and may need to focus on multiple parts of stance phase.
Predictors of non-stepping time in people with chronic stroke
(Topics in Stroke Rehabilitation, 2022-08-22) Miller, Allison; McCartney, Kiersten; Wright, Tamara; Reisman, Darcy
Background: Sedentary time is an independent construct from active time. Previous studies have examined variables associated with sedentary time to inform behavior change programs; however, these studies have lacked data sets that encompass potentially important domains. Objectives: The purpose of this study was to build a more comprehensive model containing previously theorized important predictors of sedentary time and new predictors that have not been explored. We hypothesized that variables representing the domains of physical capacity, psychosocial, physical health, cognition, and environmental would be significantly related to sedentary time in individuals post-stroke. Methods: This was a cross-sectional analysis of 280 individuals with chronic stroke. An activity monitor was used to measure sedentary (i.e. non-stepping) time. Five domains (8 predictors) were entered into a sequential linear regression model: physical capacity (6-Minute Walk Test, assistive device use), psychosocial (Activities Specific Balance Confidence Scale and Patient Health Questionnaire-9), physical health (Charlson Comorbidity Index and body mass index), cognition (Montreal Cognitive Assessment), and environmental (Area Deprivation Index). Results: The 6-Minute Walk Test (β = −0.39, p < .001), assistive device use (β = 0.15, p = .03), Patient Health Questionnaire-9 (β = 0.16, p = .01), and body mass index (β = 0.11, p = .04) were significantly related to non-stepping time in individuals with chronic stroke. The model explained 28.5% of the variability in non-stepping time. Conclusions: This work provides new perspective on which variables may need to be addressed in programs targeting sedentary time in stroke. Such programs should consider physical capacity, depressive symptoms, and physical health.
Metatarsophalangeal Joint Dynamic Stiffness During Toe Rocker Changes With Walking Speed
(Journal of Applied Biomechanics, 2022-09-12) Nigro, Luke; Arch, Elisa S.
Dynamic joint stiffness (or simply “stiffness”) is a customization criteria used to tune mechanical properties of orthotic and prosthetic devices. This study examines metatarsophalangeal (MTP) joint stiffness during the toe-rocker phase of barefoot walking and establishes baseline characteristics of MTP joint stiffness. Ten healthy individuals walked at 4 speeds (0.4, 0.6, 0.8, and 1.0 statures·s−1) over level ground. MTP sagittal plane joint angles and moments were calculated during the toe-rocker phase of stance. Least-squares linear regressions were conducted on the MTP moment versus angle curve to determine joint stiffness during early toe rocker and late toe rocker. Multilevel linear models were used to test for statistically significant differences between conditions. Early toe rocker stiffness was positive, while late toe rocker was negative. Both early toe rocker and late toe rocker stiffness increased in magnitude significantly with speed. This study establishes baseline characteristics of MTP joint stiffness in healthy walking, which previously had not been examined through a range of controlled walking speeds. This information can be used in the future as design criteria for orthotic and prosthetic ankle and ankle–foot devices that can imitate, support, and facilitate natural human foot motion during walking better than existing devices.
Reliability of Continuous Shear Wave Elastography in the Pathological Patellar Tendon
(Journal of Ultrasound in Medicine, 2022-10-27) Ito, Naoaki; Sigurðsson, Haraldur B.; Pohlig, Ryan T.; Cortes, Daniel H.; Grävare Silbernagel, Karin; Sprague, Andrew L.
Objectives Patellar tendon injuries occur via various mechanisms such as overuse, or due to surgical graft harvest for anterior cruciate ligament reconstruction (ACLR). Quantified patellar tendon stiffness after injury may help guide clinical care. Continuous shear wave elastography (cSWE) allows for the assessment of viscosity and shear modulus in tendons. The reliability of the measure, however, has not been established in the patellar tendon. The purpose of this study was to investigate the interrater reliability, intrarater reliability, and between-day stability of cSWE in both healthy and pathological patellar tendons. Methods Participants with patellar tendinopathy (n = 13), history of ACLR using bone-patellar tendon-bone autograft (n = 9), and with no history of patellar tendon injury (n = 13) were recruited. cSWE was performed 4 times by multiple raters over 2 days. Intraclass correlations (ICC) and minimum detectable change (MDC95%) were calculated. Results Good to excellent between-day stability were found for viscosity (ICC = 0.905, MDC95% = 8.3 Pa seconds) and shear modulus (ICC = 0.805, MDC95% = 27.4 kPa). The interrater reliability measures, however, were not as reliable (ICC = 0.591 and 0.532). Conclusions cSWE is a reliable assessment tool for quantifying patellar tendon viscoelastic properties over time. It is recommended, however, that a single rater performs the measure as the interrater reliability was less than ideal.
Markerless motion capture: What clinician-scientists need to know right now
(Journal of Science and Medicine in Sport Plus, 2022-11-14) Ito, Naoaki; Sigurðsson, Haraldur B.; Seymore, Kayla D.; Arhos, Elanna K.; Buchanan, Thomas S.; Snyder-Mackler, Lynn; Grävare Silbernagel, Karin
Markerless motion capture (mocap) could be the future of motion analysis. The purpose of this report was to describe our team of clinicians and scientists’ exploration of markerless mocap (Theia 3D) and share data for others to explore (link: https://osf.io/6vh7z/?view_only=c0e00984e94a48f28c8d987a2127339d). Simultaneous mocap was performed using markerless and marker-based systems for walking, squatting, and forward hopping. Segment lengths were more variable between trials using markerless mocap compared to marker-based mocap. Sagittal plane angles were most comparable between systems at the knee joint followed by the ankle and hip. Frontal and transverse plane angles were not comparable between systems. The data collection experience using markerless mocap was simpler, faster, and user friendly. The ease of collection was in part offset by the added data transfer and processing times, and the lack of troubleshooting flexibility. If used selectively with proper understanding of limitations, markerless mocap can be exciting technology to advance the field of motion analysis.
Comparing an Expanded Versus Brief Telehealth Physical Therapist Intervention for Knee Osteoarthritis: Study Protocol for the Delaware PEAK Randomized Controlled Trial
(Physical Therapy & Rehabilitation Journal, 2023-02-01) Jakiela, Jason T.; Voinier, Dana; Hinman, Rana S.; Copson, Jennifer; Schmitt, Laura A.; Leonard, Tara R.; Aily, Jéssica B; Bodt, Barry A.; White, Daniel K.
Objective The purpose of this study is to investigate whether a remotely delivered physical therapist intervention increases physical activity (PA) over 12 weeks, compared with existing web-based resources, in adults with knee osteoarthritis (OA). Methods This will be a single-center, randomized controlled trial with 2 parallel arms: (1) the Expanded Intervention (Delaware PEAK [Physical Exercise and Activity for Knee osteoarthritis]), which includes five 45- to 60-minute video conference-based sessions of supervised exercise (strengthening exercises, step goals) that are remotely delivered over 12 weeks by a physical therapist; or (2) the Brief Intervention (control group), a website that includes prerecorded videos directing participants to web-based resources for strengthening, PA, and pain management for knee OA that are freely available. The trial will enroll 100 participants who meet the National Institute for Health and Care Excellence OA clinical criteria (≥45 years old, have activity-related knee pain, and have no morning stiffness or it lasts ≤30 minutes), reside in the contiguous United States (excluding Alaska and Hawaii), and are seeking to be more physically active. Outcomes include PA (time in moderate-to-vigorous and light PA, steps per day), sedentary behaviors, treatment beliefs, and self-efficacy for exercise. Our primary outcome is moderate-to-vigorous PA. Outcomes will be measured at baseline, 12 weeks, and 24 weeks. Impact This protocol focuses on the remote delivery of physical therapy via telehealth to adults with knee OA and comes at a critical time, because the burden of inactivity is of particular concern in this population. If successful, the findings of this work will provide strong support for the broad implementation of Delaware PEAK, highlight the utility of telehealth in physical therapy, and address the critical need to utilize exercise to manage adults with knee OA through physical therapists.
Clinically relevant subgroups exist among athletes who have ruptured their anterior cruciate ligaments: A Delaware-Oslo Cohort Study
(Arthritis Care & Research, 2023-03-01) Arhos, Elanna K.; Pohlig, Ryan T.; Di Stasi, Stephanie; Risberg, May Arna; Snyder-Mackler, Lynn; Grävare Silbernagel, Karin
Objective: To identify subgroups of individuals with anterior cruciate ligament (ACL) injuries based on patient characteristics, self-reported outcomes, and functional performance at baseline, and to associate subgroups with long-term outcomes after ACL rupture. Methods: A total of 293 participants (45.7% male, mean ± SD age 26.2 ± 9.4 years, days from injury 58 ± 35) were enrolled after effusion, pain, and range of motion impairments were resolved and quadriceps strength was at least 70% of the uninvolved limb. Mixture modeling was used to uncover latent subgroups without a prior group classification using probabilistic assignment. Variables include demographics, functional testing, and self-reported outcome measures. Radiographic evidence of osteoarthritis (OA; i.e., Kellgren/Lawrence grade of ≥1) in the involved knee at 5 years after injury was the primary outcome of interest. Chi-square tests assessed differences in the presence of radiographic OA in the involved knee between subgroups at 5 years after ACL rupture. Secondary outcomes of interest included radiographic OA in the uninvolved knee, return to preinjury sport by 2 years, operative status, and clinical OA (classified using Luyten et al criteria) at 5 years. Results: Four distinct subgroups exist after ACL rupture (younger good self-report, younger poor self-report, older poor self-report, older good self-report) with 30%, 31%, 47%, and 53%, respectively, having involved knee OA. The percentage of radiographic OA was not significantly different between the groups (P = 0.059). Conclusion: The prevalence of OA in all subgroups is highly concerning. These results suggest there are unique subgroupings of individuals that may guide treatment after ACL rupture and reconstruction by providing support for developing a patient-centered approach.
Challenging the assumption of uniformity in patellar tendon structure: Regional patellar tendon morphology and mechanical properties in vivo
(Journal of Orthopaedic Research, 2023-04-08) Ito, Naoaki; Scattone Silva, Rodrigo; Sigurðsson, Haraldur B.; Cortes, Daniel H.; Silbernagel, Karin Grävare
Patellar tendons are assumed to be uniform in morphology and mechanical properties despite a higher prevalence of tendinopathies observed in the medial region. The purpose of this study was to compare the thickness, length, viscosity, and shear modulus of the medial, central, and lateral regions of healthy patellar tendons of young males and females in vivo. B-mode ultrasound and continuous shear wave elastography were performed on 35 patellar tendons (17 females, 18 males) over three regions of interest. A linear mixed-effects model (α = 0.05) was used to determine differences between the three regions and sexes followed by pairwise comparisons for significant findings. The lateral region (mean [95% confidence interval] = 0.34 [0.31–0.37] cm) was thinner compared with the medial (0.41 [0.39–0.44] cm, p < 0.001), and central (0.41 [0.39–0.44] cm, p < 0.001) regions regardless of sex. Viscosity was lower in the lateral (19.8 [16.9–22.7] Pa-s) versus medial region (27.4 [24.7–30.2] Pa-s, p = 0.001). Length had a region-by-sex interaction (p = 0.003) characterized by a longer lateral (4.83 [4.54–5.13] cm) versus medial (4.42 [4.12–4.72] cm) region in males (p < 0.001), but not females (p = 0.992). Shear modulus was uniform between regions and sexes. The thinner, and less viscous lateral patellar tendon may reflect the lower load the tendon experiences explaining the differences in regional prevalence of developing tendon pathology. Statement of Clinical Significance: Healthy patellar tendons are not uniform in morphology or mechanical properties. Considering regional tendon properties may help guide targeted interventions for patellar tendon pathologies.
Limitations in utilization and prioritization of standardized somatosensory assessments after stroke: A cross-sectional survey of neurorehabilitation clinicians
(Topics in Stroke Rehabilitation, 2023-04-16) Hoh, Joanna Eskander; Borich, Michael R.; Kesar, Trisha M.; Reisman, Darcy S.; Semrau, Jennifer A.
Background and Purpose Somatosensory impairments are common after stroke, but receive limited evaluation and intervention during neurorehabilitation, despite negatively impacting functional movement and recovery. Objectives Our objective was to understand the scope of somatosensory assessments used by clinicians in stroke rehabilitation, and barriers to increasing use in clinical practice. Methods An electronic survey was distributed to clinicians (physical therapists, occupational therapists, physicians, and nurses) who assessed at least one individual with stroke in the past 6 months. The survey included questions on evaluation procedures, type, and use of somatosensory assessments, as well as barriers and facilitators in clinical practice. Results Clinicians (N = 431) indicated greater familiarity with non-standardized assessments, and greater utilization compared to standardized assessments (p < 0.0001). Components of tactile sensation were the most commonly assessed modality of somatosensation (25%), while proprioception was rarely assessed (1%). Overall, assessments of motor function were prioritized over assessments of somatosensory function (p < 0.0001). Discussion Respondents reported assessing somatosensation less frequently than motor function and demonstrated a reliance on rapid and coarse non-standardized assessments that ineffectively capture multi-modal somatosensory impairments, particularly for proprioceptive deficits common post-stroke. In general, clinicians were not familiar with standardized somatosensory assessments, and this knowledge gap likely contributes to lack of translation of these assessments into practice. Conclusions Clinicians utilize somatosensory assessments that inadequately capture the multi-modal nature of somatosensory impairments in stroke survivors. Addressing barriers to clinical translation has the potential to increase utilization of standardized assessments to improve the characterization of somatosensory deficits that inform clinical decision-making toward enhancing stroke rehabilitation outcomes.
Information Available to Parents Seeking Education about Infant Play, Milestones, and Development from Popular Sources
(Behavioral Sciences, 2023-05-19) Orlando, Julie M.; Cunha, Andrea B.; Alghamdi, Zainab; Lobo, Michele A.
Parents commonly seek information about infant development and play, yet it is unclear what information parents find when looking in popular sources. Play, Milestone, and Development Searches in Google identified 313 sources for content analysis by trained researchers using a standardized coding scheme. Sources included websites, books, and apps created by professional organizations, commercial entities, individuals, the popular press, and government organizations/agencies. The results showed that for popular sources: (1) author information (i.e., qualifications, credentials, education/experience) is not consistently provided, nor is information about the developmental process, parents’ role in development, or determining an infant’s readiness to play; (2) milestones comprise a majority of the content overall; (3) search terminology impacts the information parents receive; (4) sources from the Milestone and Development Searches emphasized a passive approach of observing developmental milestones rather than suggesting activities to actively facilitate learning and milestone development. These findings highlight the need to discuss parents’ online information-gathering process and findings. They also highlight the need for innovative universal parent-education programs that focus on activities to facilitate early development. This type of education has potential to benefit all families, with particular benefits for families with children who have unidentified or untreated developmental delays.
The nervous system tunes sensorimotor gains when reaching in variable mechanical environments
(iScience, 2023-06-16) Maurus, Philipp; Jackson, Kuira; Cashaback, Joshua G.A.; Cluff, Tyler
Highlights: • The control of reaching is altered when facing time-varying physical disturbances • The changes in control increase responses to proprioceptive and visual feedback • Responses to feedback are tuned to the variability of the time-varying disturbances Summary: Humans often move in the presence of mechanical disturbances that can vary in direction and amplitude throughout movement. These disturbances can jeopardize the outcomes of our actions, such as when drinking from a glass of water on a turbulent flight or carrying a cup of coffee while walking on a busy sidewalk. Here, we examine control strategies that allow the nervous system to maintain performance when reaching in the presence of mechanical disturbances that vary randomly throughout movement. Healthy participants altered their control strategies to make movements more robust against disturbances. The change in control was associated with faster reaching movements and increased responses to proprioceptive and visual feedback that were tuned to the variability of the disturbances. Our findings highlight that the nervous system exploits a continuum of control strategies to increase its responsiveness to sensory feedback when reaching in the presence of increasingly variable physical disturbances. Graphical abstract available at: https://doi.org/10.1016/j.isci.2023.106756
Visual accuracy dominates over haptic speed for state estimation of a partner during collaborative sensorimotor interactions
(Journal of Neurophysiology, 2023-07-01) Lakesh, Rakshith; Sullivan, Seth R.; Germain, Laura St.; Roth, Adam M.; Calalo, Jan A.; Buggeln, John; Ngo, Truc; Marchhart, Vanessa R. F.; Carter, Michael J.; Cashaback, Joshua G. A.
We routinely have physical interactions with others, whether it be handing someone a glass of water or jointly moving a heavy object together. These sensorimotor interactions between humans typically rely on visual feedback and haptic feedback. Recent single-participant studies have highlighted that the unique noise and time delays of each sense must be considered to estimate the state, such as the position and velocity, of one’s own movement. However, we know little about how visual feedback and haptic feedback are used to estimate the state of another person. Here, we tested how humans utilize visual feedback and haptic feedback to estimate the state of their partner during a collaborative sensorimotor task. Across two experiments, we show that visual feedback dominated haptic feedback during collaboration. Specifically, we found that visual feedback led to comparatively lower task-relevant movement variability, smoother collaborative movements, and faster trial completion times. We also developed an optimal feedback controller that considered the noise and time delays of both visual feedback and haptic feedback to estimate the state of a partner. This model was able to capture both lower task-relevant movement variability and smoother collaborative movements. Taken together, our empirical and modeling results support the idea that visual accuracy is more important than haptic speed to perform state estimation of a partner during collaboration. NEW & NOTEWORTHY Physical collaboration between two or more individuals involves both visual and haptic feedback. Here, we investigated how visual and haptic feedback is used to estimate the movements of a partner during a collaboration task. Our experimental and computational modeling results parsimoniously support the notion that greater visual accuracy is more important than faster yet noisier haptic feedback when estimating the state of a partner.
Clinical Mental Health Measures and Prediction of Postconcussion Musculoskeletal Injury
(Journal of Athletic Training, 2023-07-31) Buckley, Thomas A.; Bryk, Kelsey N.; Enrique, Alexander L.; Kaminski, Thomas W.; Hunzinger, Katherine J.; Oldham, Jessie R.
Context The rate of lower extremity musculoskeletal injury (LE MSK) is elevated after concussion; however, the underlying mechanism has not been elucidated. Physical characteristics have been investigated despite poorer mental health being a common postconcussion complaint and linked to MSKs. Objective To evaluate the role of mental health as a predictor of postconcussion LE MSK. Design Case-control study. Setting Intercollegiate athletic training facility. Patients or Other Participants A total of 67 National Collegiate Athletic Association Division I student-athletes (n = 39 females) who had been diagnosed with a sport-related concussion. Main Outcome Measure(s) The Brief Symptom Inventory-18, Hospital Anxiety and Depression Scale, and Satisfaction With Life Scale (SWLS) measures were completed at baseline (preseason) and on the day participants were cleared for unrestricted return to play (RTP) after a concussion. Two binary logistic regressions were used to predict postconcussion LE MSK within a year, one for the baseline time point and the second for the RTP time point. A 2 (group: LE MSK, no LE MSK)-by-2 (time: baseline, RTP) repeated-measures analysis of variance compared performance between baseline and RTP. Results Subsequent LE MSKs were sustained by 44 participants (65.7%). The only significant predictor of postconcussion LE MSK was the SWLS score at RTP, with Exp(B) = 0.64, indicating that an increased (improved) SWLS score was associated with a lower LE MSK rate. No significant interactions were present between mental health measures and subsequent MSK (P values = .105–.885). Conclusions Limited associations were evident between postconcussion LE MSK and scores on commonly used measures of anxiety, depression, and satisfaction with life. Reported increased satisfaction with life was associated with a decreased injury risk, which warrants further attention. Our results suggest that these measures of anxiety, depression, and satisfaction with life have limited value in assisting sports medicine clinicians with determining which student-athletes are at elevated risk of postconcussion LE MSK. Key Points Measures of anxiety and depressive symptoms were not predictive of elevated postconcussion lower extremity musculoskeletal injury. Greater satisfaction with life was associated with a decreased risk of postconcussion lower extremity musculoskeletal injury.

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