An examination of undergraduate research in the field of biomechanics across multiple US-based institutions.

Undergraduate research is commonly performed in many STEM disciplines and has a wide array of benefits for students, laboratories, principal investigators, and institutions. While many fields have assessed best practices and the cost-benefit analysis of incorporating undergraduates in research, this has not yet been addressed in biomechanics. This paper represents the perspectives of seven members of the American Society of Biomechanics (ASB) Teaching Biomechanics Interest Group (TBIG). These TBIG members discussed their own experience regarding the opportunities, challenges, and benefits of undergraduate research and this perspective paper presents the commonalities found during these interactions. The TBIG members reported that undergraduate research was assessed similarly to graduate student research, which often led to an underestimation of productivity for both the student and overall lab output. While undergraduate researchers are not often responsible for publications and grant funding, they are instrumental in lab productivity in other ways, such as through human subject approvals, conference abstract presentations, student thesis projects, and more. Students benefit from these experiences, not necessarily by continuing in research, but by learning skills and making connections which further them in any career. While this perspective presents the experience of seven professors in the United States, future studies should further assess the cost-benefit relationship of working with undergraduates in biomechanics research on a global scale. A clearer picture of this analysis could benefit students, faculty, and administrators in making difficult decisions about lab productivity and assessment.

Characterizing impact and providing perspective by assessing National Biomechanics Day events.

In this Perspective article we make the case for assessing National Biomechanics Day in order to better understand and maximum its impact. We present the opportunities and benefits that exist to assess National Biomechanics Day, as well as suggest assessment resources and tools that can be utilized. A case study is also included that details the ways that including assessment via a pre- and post-National Biomechanics Day survey provided insight into how our event changed student perceptions related to biomechanics, as well as informed us about how we might improve our event in the future.

Quantifying national biomechanics day's impact on student perceptions toward biomechanics: A multisite pilot study.

National Biomechanics Day (NBD) is an international celebration of biomechanics that seeks to increase the awareness and appreciation of biomechanics among the high school community. Initial research supports the positive effects of NBD on students' attitudes toward the field of biomechanics; however, quantitative evidence remains scarce. The purpose of this study was to quantify changes in high school students' perceptions toward biomechanics after participating in NBD events to better understand the impact of NBD. Data were collected at two locations during the 2019 NBD season. Surveys were collected before and after NBD events for 112 high school students from Montana and North Carolina. Paired pre- versus post-NBD surveys for the aggregate sample population suggest that students perceived biomechanics as more appealing (p = 0.050), exciting (p = 0.007), and important (p = 0.018) following the NBD events. Students did not report a change in whether they could see themselves in a biomechanics-related career (p = 0.49). These findings further support the ability for NBD events to positively impact students' perceptions toward biomechanics, although opportunities persist to increase student career interest in biomechanics. This paper presents and discusses the study's results, interpretations, limitations, and implications for future research on biomechanics outreach activities.

Impact of an ankle foot orthosis on reactive stepping in young adults.

BACKGROUND: Ankle-foot orthoses (AFOs) have been shown to improve gait and static balance in individuals with lower extremity weakness and instability. However, the effects of AFOs on dynamic balance reactions including reactive stepping responses are not well known. Therefore, the purpose of this study was to determine the effects of an AFO on reactive stepping responses in healthy young adults. RESEARCH QUESTION: Does an AFO alter reactive stepping responses in healthy young adults? METHODS: Twenty healthy young adults completed 10 reactive stepping trials using a lean-and-release system for each of three AFO conditions: 1) no AFO, 2) AFO on left leg and 3) AFO on right leg. Trials were recorded using 3D motion capture and force plates. Stepping limb preference and temporal, spatial, and kinematic variables were measured. Differences between conditions were determined by a one-way ANOVA with a Tukey post-hoc. RESULTS: With no AFO, participants demonstrated a preference for stepping with the right leg, 7.0 ± 3.9 of 10 trials. With an AFO on the right leg, this preference decreased to 5.7 ± 4.4 (p = 0.03). With an AFO on the left leg, this preference increased to 8.1 ± 3.3 (p = 0.03). Reaction times were not significantly different between conditions, but participants took a significantly shorter reactive step with the leg wearing the AFO. Peak ankle, knee, and hip joint angles were significantly less with the AFO on the stepping limb compared to the stance limb. SIGNIFICANCE: This study shows that AFO use can influence reactive stepping limb preference and stepping limb kinematics in healthy young adults. These results can inform future research on AFO users with gait impairments. These finding may also be helpful in developing interventions to address the specific effects of an AFO on reactive stepping responses.

Measuring Vestibular Contributions to Age-Related Balance Impairment: A Review.

Aging is associated with progressive declines in both the vestibular and human balance systems. While vestibular lesions certainly contribute to imbalance, the specific contributions of age-related vestibular declines to age-related balance impairment is poorly understood. This gap in knowledge results from the absence of a standardized method for measuring age-related changes to the vestibular balance pathways. The purpose of this manuscript is to provide an overview of the existing body of literature as it pertains to the methods currently used to infer vestibular contributions to age-related imbalance.

The effects of a positional feedback device on rollator walker use: a validation study.

BACKGROUND: According to clinical guidelines, rolling walker users should walk with their feet between the posterior wheels of the walker; however approximately 50% of users do not. OBJECTIVE: To describe the development and effects of a custom device designed to attach to a walker and provide visual feedback to encourage improved user position. METHODS: Fourteen older adults participated in this study to validate the effects of this device when a 10% decrease in the users' habitual distance away from the walker was encouraged via feedback. Users' relative distances were recorded using a non-contact distance sensor within the device, while kinematics were measured using commercial wearable wireless inertial sensors. RESULTS: Individuals were able to ambulate on average 20% closer or more to their walker when prescribed the visual feedback. This was primarily achieved through a reduction in shoulder flexion. Trunk and cervical postures were less generalizable as only small and variable changes were observed. CONCLUSIONS: These findings suggest that the device has promise, as individuals attended to the device and walked in a position closer to that recommended by clinical guidelines. The device did not appear to improve posture. Future work is needed to determine long-term effects.

A new perspective on transient characteristics of quiet stance postural control.

Postural control provides insight into health concerns such as fall risk but remains relatively untapped as a vital sign of health. One understudied aspect of postural control involves transient responses within center of pressure (CoP) data to events such as vision occlusion. Such responses are masked by common whole-trial analyses. We hypothesized that the transient behavior of postural control would yield unique and clinically-relevant information for quiet stance compared to traditionally calculated whole-trial CoP estimates. Three experiments were conducted to test different aspects of this central hypothesis. To test whether transient, epoch-based characteristics of CoP estimates provide different information than traditional whole-trial estimates, we investigated correlations between these estimates for a population of young adults performing three 60-second trials of quiet stance with eyes closed. Next, to test if transient behavior is a result of sensory reweighting after eye closure, we compared transient characteristics between eyes closed and eyes open conditions. Finally, to test if there was an effect of age on transient behavior, we compared transient characteristics during eyes closed stance between populations of young and older adults. Negligible correlations were found between transient characteristics and whole-trial estimates (p>0.08), demonstrating limited overlap in information between them. Additionally, transient behavior was exaggerated during eyes closed stance relative to eyes open (p<0.044). Lastly, we found that transient characteristics were able to distinguish between younger and older adults, supporting their clinical relevance (p<0.029). An epoch-based approach captured unique and potentially clinically-relevant postural control information compared to whole-trial estimates. While longer trials may improve the reliability of whole-trial estimates, including a complementary assessment of the initial transient characteristics may provide a more comprehensive characterization of postural control.

The patterning of local variability during the acquisition of a novel whole-body continuous motor skill in young adults.

There is increasing evidence that movement variability during motor skill acquisition plays a functional role. Specifically, initial variability might represent exploration of the possible motor space for solutions and error identification. Following practice, individuals might exploit a reduced amount of motor solutions to execute the task. While this variability pattern has been supported during discrete upper limb and multi-finger force tasks, there is a paucity of evidence for continuous whole-body motor tasks. Therefore, the purpose of this study was to characterize the role of variability during the acquisition of a whole-body continuous motor task across practice sessions in young adults. Twelve young adults aged 18-35-years participated in this study. Subjects practiced a novel, sagittal plane task, the kettlebell swing, using an online training video. We conducted an uncontrolled manifold analysis to partition local variability of the configuration of the kettlebell and body segments based on their impact on the position of the center-of-mass (COM) in the sagittal plane. Our results demonstrated that following initial practice, variability that did not affect the COM position remained elevated, suggesting sustained exploration of motor solutions. Following multiple practice sessions, variability related to motor solutions decreased, potentially indicating exploitation. The results from this study support the proposal that young adults initially utilize a range of motor solutions when acquiring a whole-body motor skill, followed by exploitation of stereotypic movement.

Age Stratification and Sample Entropy Analysis Enhance the Limits of Stability Tests for Older Adults.

The objective of this study was to determine if a foam testing condition and/or nonlinear analysis methods can be used to identify differences between age stratified subgroups of older adults when conducting the Limits of Stability assessment. Ninety older adults participated in this study. A force plate was used to record center of pressure data during Limits of Stability testing on a firm and foam surface. Participants were grouped into age-stratified subgroups: young-old (60-69 years), middle-old (70-79 years), and old-old (80+ years). Anterior-posterior (A/P) and medial-lateral (M/L) sway ranges and sample entropy values were calculated. The young-old group had significantly larger A/P and M/L sway ranges than the old-old group on both surfaces. A/P sample entropy increased significantly with age. M/L sample entropy increased significantly with age between the young-old and old-old and the middle-old and old-old groups. Sample entropy values between surfaces significantly differed for all groups. These results indicate Limits of Stability differences occur between older adults of different age groups and should be taken into consideration for clinical and research testing. Nonlinear analysis may help further identify differences in Limits of Stability performance while use of a foam surface is of limited additional value.

Identification of key outcome measures when using the instrumented timed up and go and/or posturography for fall screening.

The Timed Up and Go (TUG) has been commonly used for fall risk assessment. The instrumented Timed Up and Go (iTUG) adds wearable sensors to capture sub-movements and may be more sensitive. Posturography assessments have also been used for determining fall risk. This study used stepwise logistic regression models to identify key outcome measures for the iTUG and posturography protocols. The effectiveness of the models containing these measures in differentiating fallers from non-fallers were then compared for each: iTUG total time duration only, iTUG, posturography, and combined iTUG and posturography assessments. One hundred and fifty older adults participated in this study. The iTUG measures were calculated utilizing APDM Inc.'s Mobility Lab software. Traditional and non-linear posturography measures were calculated from center of pressure during quiet-standing. The key outcome measures incorporated in the iTUG assessment model (sit-to-stand lean angle and height) resulted in a model sensitivity of 48.1% and max re-scaled R2 value of 0.19. This was a higher sensitivity, indicating better differentiation, compared to the model only including total time duration (outcome of the traditional TUG), which had a sensitivity of 18.2%. When the key outcome measures of the iTUG and the posturography assessments were combined into a single model, the sensitivity was approximately the same as the iTUG model alone. Overall the findings of this study support that the iTUG demonstrates greater sensitivity than the total time duration, but that carrying out both iTUG and posturography does not greatly improve sensitivity when used as a fall risk screening tool.

Manual and Cognitive Dual Tasks Contribute to Fall-Risk Differentiation in Posturography Measures.

Falls occur in 33% of older adults each year, some leading to moderate to severe injuries. To reduce falls and fall-related injuries, it is important to identify individuals with subtle risk factors elevating their likelihood of falling. The objective of this study was to determine how postural sway measures differed between fallers and nonfallers under standard and dual-task conditions. Quietstanding posturography measures were collected from 150 older adults during standard, cognitive, manual, and cognitive+manual tasks, and analyzed through traditional and nonlinear analyses. Of the traditional measures, M/L sway range and 95% confidence ellipse sway area showed statistically significant differences in all 4 test conditions between fallers and nonfallers. Although the manual dual task showed the most stable balance, effect sizes demonstrated larger differences between fallers and nonfallers. Nonlinear analysis revealed M/L sample entropy and M/L α-scaling exponent differentiating between fallers and nonfallers, with the cognitive task demonstrating larger differences. Based on the results, it is recommended to: (1) apply M/L sway range and 95% confidence ellipse area, (2) use the manual task to differentiate between fallers and nonfallers when using traditional analyses, and (3) use the cognitive task and M/L alpha and M/L sample entropy when using nonlinear analyses.

Subtle Differences During Posturography Testing Can Influence Postural Sway Results: The Effects of Talking, Time Before Data Acquisition, and Visual Fixation.

The goal of this study was to examine the effects of 3 factors and their interactions on posturography: a period of time to become accustomed to the force platform before the initiation of data collection, presence of a visual fixation point, and participant talking during testing. The postural stability of 30 young adults and 30 older adults was evaluated to determine whether any observed effects were confounded with age. Analysis of variance techniques were used to test all possible combinations of the 3 factors. We hypothesized that all 3 factors would significantly affect postural stability. For both participant groups, the results suggest that a period of time to become accustomed to the force platform before the initiation of data collection and a visual fixation point significantly affect postural control measures, while brief participant talking does not. Despite this, no significant interactions existed suggesting that the effects of these factors, which may occur in clinical testing, do not depend on each other. Our results suggest that inconsistencies in posturography testing methods have the potential to significantly affect the results of posturography, underscoring the importance of developing a standardized testing methodology.

Using Posturography to Examine the Immediate Effects of Vestibular Therapy for Children with Autism Spectrum Disorders: A Feasibility Study.

AIMS: The primary objective of this study was to determine the feasibility of using posturography to monitor acute changes in postural control induced by a Sensory Integration (SI) therapy intervention. A secondary objective was to identify which posturography outcome parameters, tests conditions and data analysis methods might be most useful in identifying post-intervention changes. METHODS: Five children with Autism Spectrum Disorder (ASD) and five children with typical development (TD) participated in a 10 min vestibular swing activity and had their postural stability evaluated pre- and post-intervention under four different sensory testing conditions. Sway ranges, mean sway velocity, sway root mean square (RMS), and sample entropy were calculated from center of pressure (COP) data. RESULTS: All five children with ASD demonstrated decreased mean sway velocity in the eyes open/flat plate condition post-intervention with an average decrease of 5.87 ± 2.69 mm/s. Four of the five children with ASD demonstrated an increase in RMS and a decrease in anterior/posterior sample entropy post-intervention in the eyes closed, foam pad condition and eyes open, flat plate condition respectively. CONCLUSION: Posturography may be useful for assessing acute physiologic responses to an SI therapy intervention and warrants further investigation.

Measures of balance performance are affected by a rested versus fatigued testing condition in people with multiple sclerosis.

OBJECTIVE: To investigate the effects of a rested and fatigued testing condition on measures of balance in people with multiple sclerosis (MS). DESIGN: Prospective observational study. SETTING: Academic research laboratory. PARTICIPANTS: Fifteen ambulatory adults with relapsing remitting or secondary progressive MS with moderate disability. METHODS: Measures of postural control, dynamic balance, and fatigue were assessed during a "rested" and "fatigued" testing condition on separate days. MAIN OUTCOME MEASUREMENTS: Static posturography was used to assess postural control. The Mini-Balance Evaluation Systems Test and Dynamic Gait Index were used to assess dynamic balance. The chronic fatigue level was measured by using the Fatigue Severity Scale, and acute fatigue was assessed by using a visual analog scale at multiple time points during testing. RESULTS: During the fatigued condition, the participants reported a significant (P < .05) increase in acute fatigue levels (visual analog scale) and demonstrated a significant (P < .05) decrease in performance on measures of postural control and dynamic balance when compared with the rested condition. However, no significant relationship was identified between the changes in fatigue and changes in balance performance. CONCLUSIONS: Measures of balance performance and acute fatigue may be affected by rested versus fatigued testing conditions in people with MS. However, no significant relationships between changes in balance and fatigue were identified. Therefore, clinicians should use caution when making assumptions about the influence of fatigue on balance performance and should test for individual responses. Clinicians and researchers should also consider controlling for factors such as time of day and prior physical activity when administering standardized measures of balance in people with MS.

A group kickboxing program for balance, mobility, and quality of life in individuals with multiple sclerosis: a pilot study.

BACKGROUND AND PURPOSE: Balance and mobility impairments are common in individuals with multiple sclerosis (MS). The primary purpose of this pilot study was to evaluate the feasibility of a 5-week group kickboxing program and to measure changes in balance, mobility, and quality of life in individuals with MS associated with this training. METHODS: This single-group repeated-measures study involved a convenience sample of 15 individuals with MS who had minimal to moderate levels of disability and were recruited from the community. Eleven participants completed all phases of testing and training. The intervention was a 5-week group kickboxing program performed 3 times per week. Outcome measures were assessed 5 weeks prior to the intervention, 1 week prior to the intervention, and within 1 week of completing the intervention. Outcome measures include gait speed, Timed Up & Go test, Berg Balance Scale, Dynamic Gait Index, Mini-BESTest, Activities Specific Balance Confidence scale, and the Multiple Sclerosis Quality of Life Survey. RESULTS: There were significant improvements in gait speed, some clinical measures of balance, and balance confidence following the intervention but no changes were observed in health-related quality of life. There were no unanticipated adverse events and compliance was high. CONCLUSION: Group kickboxing appears to be a feasible exercise activity for individuals with MS that may lead to improvement in select measures of balance and mobility. However, the clinical relevance of these findings is yet to be determined. Further investigation of this novel intervention may be warranted.

Feasibility and effects of a group kickboxing program for individuals with multiple sclerosis: a pilot report.

BACKGROUND AND PURPOSE: Balance and mobility impairments are common in persons with multiple sclerosis (MS). The primary purpose of this pilot program was to evaluate the feasibility and the effects of group kickboxing on balance and mobility in individuals with MS. METHODS: Four individuals with relapsing-remitting or secondary progressive MS participated in a group kickboxing program two times per week for 8 weeks. Outcome measures included the Berg Balance Scale (BBS), Dynamic Gait Index (DGI), Timed Up and Go (TUG), walking speed and the Activities Specific Balance Confidence Scale (ABC). RESULTS: Following training, 3 of 4 participants had improvements in BBS performance. All participants demonstrated improvements in the DGI. Changes in the TUG, ABC, and walking speed were more variable. CONCLUSION: Group kickboxing appears to be a feasible exercise activity for individuals with MS and may lead to improvement in select measures of balance. Further investigation may be warranted.

Development of a protocol for improving the clinical utility of posturography as a fall-risk screening tool.

BACKGROUND: The usefulness of posturography in the clinical screening of older adults for fall risk has been limited by a lack of standardization in testing methodology and data reporting. This study determines which testing condition and postural sway measures best differentiate recurrent fallers and nonrecurrent fallers. METHODS: One hundred and fifty older adults were categorized based on their fall status in the past year. Participants performed four quiet-standing tasks, eyes open and eyes closed in both comfortable and narrow stance, for 60 seconds while standing on a force-measuring platform. Traditional and fractal measures were calculated from the center of pressure data. Logistic regression was performed to determine the model for each condition that best discriminated between recurrent fallers and nonrecurrent fallers. RESULTS: The eyes closed comfortable stance condition, with its associated model, best differentiated recurrent fallers and nonrecurrent fallers. Medial-lateral sway velocity, anterior-posterior short-term α-scaling exponent, medial-lateral short-term α-scaling exponent, mean frequency, body mass index, and age were included in this model. Sensitivity of the model was 75%, and specificity was 94%. CONCLUSIONS: This resulting model demonstrates potential to differentiate recurrent fallers and nonrecurrent fallers in an eyes closed comfortable stance condition. The inclusion of traditional sway parameters, fractal measures, and personal characteristics in this model demonstrates the importance of considering multiple descriptions of postural stability together rather than using only a single measure to establish fall risk.