Movement pattern definitions for resistance training behavior measurement in diabetes.

Type 2 diabetes can result in debilitating vascular complications, and resistance training (RT) is an effective therapy for improving cardiovascular outcomes. However, only 10-30% of adults meet the public health guidance for RT. While current RT guidelines focus on targeting major muscle groups, guidance specific to simplified movement categorization may augment understanding of RT programming and improve uptake and outcomes. Current movement pattern definitions and descriptions lack clarity, accuracy, and consistency. This paper proposes movement definitions and descriptions to be used for RT intervention design and prescription, and includes the following categories: hip, knee, ankle, vertebral column, vertical push, horizontal push, vertical pull, and horizontal pull. These categories are intended to aid clinicians, researchers, and trainers in RT surveillance and RT intervention design for improving vascular complications in type 2 diabetes. Simplified RT program design using these categories may also facilitate greater RT program understanding and adherence for patients.

Acute Knee Crutch Use Provokes Changes to Postural Strategy.

Single-leg knee crutches are a relatively new, hands-free mobility assistive device with benefits over standard axillary crutches. Our main goal in this study was to evaluate balance ability in a healthy population upon first exposure to the knee crutch device. We had 20 healthy individuals (M age = 21.1; SD = 1.5 years) complete baseline static and dynamic balance tests on a force plate, followed by knee crutch fitting, a self-selected duration of ambulation practice, and another round of balance testing while wearing the knee crutch. We used the BTrackS Balance Test (BBT) to measure static balance, and the BTrackS Limits of Stability (BLOS) test to measure dynamic balance, and we created a custom lateral bias score from the BLOS results. On average, participants self-selected 3.1 minutes of ambulation practice. Wearing the knee crutch caused a near doubling of static balance path length and a large reduction in percentile ranking on the BBT. Dynamic balance area was more than halved (p < .001), with lateral bias scores during the BLOS, indicating that participants heavily favored their non-crutched leg (p < .001). Our results indicate that static and dynamic balance were significantly altered when wearing the knee crutch, and participants seemed to switch to a single leg stance strategy. Despite these balance changes, participants were quickly ready and willing to complete independent ambulation and balance testing procedures using the single-leg knee crutch.

An initial set of reference values for the Balance Tracking System (BTrackS) Limits of Stability protocol.

BACKGROUND: The Balance Tracking System (BTrackS) Limits of Stability (LOS) protocol is a relatively new means of evaluating unconstrained dynamic postural control ability. While the reliability of this protocol has previously been established, reference data is currently unavailable to assist in the interpretation of results. RESEARCH QUESTION: What are typical reference values for the BTrackS LOS protocol with respect to sex, height, and BMI? METHODS: A cross= -section of 800 healthy, young adults (aged 18-29 years; 368 men, 432 women) were administered the BTrackS LOS protocol. Sex, height and weight variables were also captured for the participants. RESULTS: Results of a stepwise linear regression showed that the outcome measure for BTrackS LOS testing (i.e. LOS Area) was larger in taller individuals and in men. Based on these findings, four percentile ranking categories were established and associated look-up tables created. SIGNIFICANCE: The reference values provided by this study offer much needed guidance to clinicians and researchers for the determination of dynamic balance abnormalities based on BTrackS LOS testing.

Verbal Encouragement Provokes Significant Increases in Maximal Volitional Dynamic Postural Sway.

Limits of Stability protocols are typically target-oriented, leaving volitional aspects of control unobservable. A novel unconstrained protocol, volitional Limits of Stability (vLOS), shows high test-retest-reliability. We tested if verbal encouragement impacts this protocol. Forty healthy young adults (age 20.1 ± .9 years) performed three trials of vLoS with instructions that were agnostic to strategy or vigor, except trial three included verbal encouragement. Total sway area was used to metric the maximum volitional dynamic sway during each 1-min trial. One-way, repeated-measures ANOVA revealed significant differences (F(2,117) = 41.56, p < 0.0001, ηp2 = 0.52) due to encouragement. Specifically, follow-up paired t-tests showed no difference in sway area between the first two trials (p = 0.61), while trial three was much larger than trials one and two (p < 0.0001). Significant, large increases in sway area with verbal encouragement indicate that top-down mechanisms should be considered in theories of postural control. As well, clinical utilization of novel vLOS should be careful with word selection and delivery of protocol instructions.HIGHLIGHTSLimits of Stability balance tests typically include a goal directed instruction and metrics.Dynamic postural sway should be tested in a task affording participant volitional control.A novel volitional Limits of Stability protocol has been developed.Maximal dynamic postural sway responds to motivating instructions.Psychological factors of postural sway control deserve further investigation.

Six Weeks of at Home BTrackS Target Tracking Training Induces Sustained Dynamic Balance Improvement in Healthy Young Adults.

Purpose: The Balance Tracking System's Target Tracking Training protocol requires an individual to keep an onscreen dot within a moving target circle via leaning movements that are sensed by a Balance Tracking System's balance plate. The present study sought to determine for the first time if short duration at-home training using Balance Tracking System's Target Tracking Training could improve dynamic balance. Methods: Fifteen healthy young adults (mean age = 22.4 years) performed Balance Tracking System's Target Tracking Training for six weeks at home, with an average of five, three-minute sessions per week. The first three weeks of Balance Tracking System's Target Tracking Training were completed on the firm surface of a Balance Tracking Systems Balance Plate, while the final three weeks were performed on a foam cushion on top of the plate. This was followed by a three-week retention period where participants performed no training. Dynamic balance changes were assessed at multiple timepoints with the Balance Tracking System's Limits of Stability protocol. Results: Participants significantly improved Balance Tracking System's Target Tracking Training from the first to last day of training in both three-week periods (p<0.01). This increase was mirrored by improved Balance Tracking System's Limits of Stability results. Specifically, Balance Tracking System's Limits of Stability area (ie dynamic balance) increased significantly from Baseline to the end of the first three weeks of training (p<0.001), and again after the second three weeks (p<0.01). These gains were maintained following the retention period. Conclusion: The present findings support use of short duration Balance Tracking System's Target Tracking Training to improve dynamic balance at home. This increase in dynamic balance could ultimately be used a practical means of improving athletic performance.

Lower Limb Asymmetry Evaluation Using the Balance Tracking System (BTrackS) Single Leg Stance Protocol.

Single Leg Stance (SLS) balance testing is a common means of determining lower limb asymmetries in motor behavior. The Balance Tracking System (BTrackS) Balance Plate is a low-cost, portable force plate for objectively obtaining balance measurements. The present study provides the first known balance results for the BTrackS SLS protocol. BTrackS SLS testing was conducted on 161 young adults (90 women, 71 men) according to the test's standardized instructions. Specifically, participants performed one-legged (left or right) stance on the BTrackS Balance Plate for four, (2 practice, 2 actual) 20 s trials. SLS test outputs included total Center of Pressure path length and absolute symmetry index. Results showed that women had better SLS performance than men and that both sexes performed better on the actual compared to practice trial. Systematic one-sample t-tests of the Absolute Symmetry Index measures showed that a difference of 16% or greater between legs represented asymmetric performance. These results have clear value for individuals using BTrackS SLS testing to evaluate potential asymmetries. Additionally, these findings agree with previous reports showing sex differences favoring women on tests of static balance, and validate the use of a practice trial in the BTrackS SLS protocol.

The influence of flexion distraction spinal manipulation on patients with lumbar spinal stenosis: A prospective, open-label, single-arm, pilot study.

OBJECTIVE: Evaluate chiropractic care including flexion distraction spinal manipulation for improving function, symptoms and performance-based mobility in patients with lumbar spinal stenosis (LSS) using a pretest-posttest design. METHODS: Data were collected at baseline, midpoint and final visits prior to care on each visit. Objective data included Timed Up and Go, Five Times Sit to Stand, and balance (force plate). An additional balance assessment was also conducted after care on the baseline visit. Subjective data included: Activities-Specific Balance Confidence Scale, Zurich Claudication Questionnaire, and pain ratings. Balance data were securely transferred via iDrive; the others were collected via REDCap. RESULTS: Twelve patients (mean age = 83.5 years ± 5.71) completed the average midpoint visit at 9 visits and the final visit at 13.7 visits. Timed Up and Go and Five Times Sit to Stand Test decreased by 5.2 and 6.7 s at midpoint and 5.4 and 5.7 s at the final visit, respectively compared to the baseline visit (p < 0.05). Baseline visit pre-post reductions were found in anterior-posterior sample entropy and mean frequency of postural sway (p < 0.05). No balance change was found between baseline and mid or final visits. All subjective measures had statistically and clinically meaningful improvement. CONCLUSION: Significant improvement in objective and subjective outcomes were found after a pragmatic course of care including spinal manipulation in LSS patients.

Test-Retest Reliability of the Balance Tracking System Modified Clinical Test of Sensory Integration and Balance Protocol Across Multiple Time Durations.

BACKGROUND: Postural control is critical for body sway control and is subserved by three sources of sensory feedback (ie, vision, proprioception and vestibulation). A method for determining the relative contribution of each sensory feedback source to postural control is the modified clinical test of sensory integration and balance for the balance tracking system (BTrackS). However, this method has not yet been evaluated for test-retest reliability. PURPOSE: To determine the test-retest reliability of the modified clinical test of sensory integration and balance protocol for the BTrackS across multiple time intervals. METHODS: Three groups of healthy young adults performed the BTrackS modified clinical test of sensory integration and balance protocol four times separated by either one day, one week or one month. Within each time duration group, and condition, differences in total center of pressure path length were determined from one test session to the next and intra class correlation coefficient categorizations were made. RESULTS: In all but one case, no significant difference in performance was seen from one testing session to the next. The one significant difference found was a decrease in total center of pressure path length from day 1 to day 2 in the vestibular condition of the group tested daily. Intra class correlation coefficient results largely indicated fair-good reliability across time durations and test conditions. CONCLUSION: The present study largely supports use of the BTrackS modified clinical test of sensory integration and balance protocol as a means of probing the sensory contributions to balance performance across multiple time durations.

The Effects of Chemotherapy-Induced Polyneuropathy on Postural Balance.

While cancer prevalence and survival rates are increasing, cancer-treatment-related functional decline and decreased quality of life are on the rise. Adverse side effects such as polyneuropathy are commonly associated with neurotoxic chemotherapeutic agents (i.e., taxanes or platinums) resulting in a decrease in postural balance and an increased risk for falls. This case report highlights an adult with polyneuropathy who received five months of chemotherapy treatment for a breast cancer diagnosis. Measurements included sensory integration of balance control using the BTrackS modified Clinical Test of Sensory Integration and Balance (mCTSIB) protocol and the Timed Up and Go (TUG) test. Compared to normative data, the participant demonstrated poor balance control in all conditions. Specifically, the results indicated proprioception was the most compromised component of balance control. The participant also demonstrated a slower TUG time compared to women of similar age. Our findings highlight the value of quantitative assessment of balance control following chemotherapy. More research would be needed to further support the tailored therapeutic approaches to prevent falls following chemotherapy treatment.

Postural Control, Dual Task Performance and Executive Function Following an Ultramarathon.

As research into the postural and cognitive effects of ultramarathon running is sparse and still needed, we investigated the effect of ultramarathon running on runners' postural control, dual task postural control and a measure of executive function-the flanker test, expecting fatigue-related deterioration on each measure. We used a pre- and post-test research design with 14 runners who completed (a) postural assessment with eyes open and closed, on a flat surface and on foam during (b) a two-choice reaction time dual task postural assessment, and (c) an executive function modified flanker task. With regard to postural stability, we observed, after running, increased anterior-posterior (AP) path length and AP root mean square (RMS) and reductions in both mediolateral (ML) RMS and ML median frequency. Dual task analysis showed reduced ML RMS prior to the race, whereas the effect was absent afterwards. Reaction times were not significantly altered between pre-post or surface conditions assessments. There were no statistically significant differences in mean modified flanker scores before and after the race. These data demonstrated that, following an endurance run, there were plane specific movement adaptations in postural sway that may have resulted from neuroprotective changes under extreme fatigue.

Immediate impact of extremity manipulation on dual task performance: a randomized, crossover clinical trial.

BACKGROUND: Previous research demonstrated that manipulation of the extremities was associated with changes in multisegmental postural sway as well as improvement in a lower extremity balancing task. We were interested if these effects would extend to an upper extremity task. Our aim in this study was to investigate whether extremity manipulation could influence dual task performance where the explicit suprapostural task was balancing a water filled tube in the frontal plane. METHODS: Participants were healthy volunteers (aged 21-32 years). Upper- or lower-extremity manipulations were delivered in a participant and assessor blinded, randomized crossover, clinical trial. Postural (center of pressure) and suprapostural (tube motion) measurements in the frontal plane were made pre-post manipulation under eyes open and eyes closed conditions using a BTrackS™ force plate and a Shimmer inertial measurement unit, respectively. Pathlength, range, root mean square and sample entropy were calculated to describe each signal during the dual task performance. RESULTS: There was no main effect of manipulation or vision for the suprapostural task (tube motion). However, follow-up to interaction effects indicates that roll pathlength, range and root means square of tube motion all decreased (improvement) following lower extremity manipulation with eyes open. Regarding the postural task, there was a main effect of manipulation on mediolateral center of pressure such that pathlength reduced with both upper and lower extremity manipulation with larger decreases in pathlength values following upper extremity manipulation. CONCLUSION: Our findings show that manipulation of the extremities enhanced stability (e.g. tube stabilization and standing balance) on performance of a dual task. This furthers the argument that site-specific manipulations influence context specific motor behavior/coordination. However, as this study focused only on the immediate effects of extremity manipulation, caution is urged in generalizing these results to longer time frames until more work has been done examining the length of time these effects last. TRIAL REGISTRATION: Clinicaltrials.gov , NCT03877367 , Registered 15 March 2019. Data collection took place July 2019.

Validation of a Portable Force Plate for Evaluating Postural Sway.

Measurements of postural sway are used to assess physiological changes due to therapy or sport training, or to describe group differences based on activity history or disease status. Portable force plates have been widely adopted for this purpose, leading us in this study to validate with linear and nonlinear metrics the posturographic data derived from both a portable plate (Natus) when compared to an in-ground plate (Bertec). Twenty participants stood on each plate for two trials each, with and without a foam perturbation and with and without eyes open on each surface. We calculated measures of path length, range, root mean squares, sample entropy, and correlation dimensions from center of pressure traces on each plate. An intraclass correlation coefficient across trials from each plate in each condition indicated satisfactory overall reliability (ICC consistency), supporting the use of either plate for postural sway research and interventions. Additionally, our results generally supported common validity (ICC absolute agreement), though, the specific degree of similarity differed for each of the tested metrics of postural sway, especially when considering whether or not data was filtered. For situations in which participants cannot visit a laboratory (e.g. performing athletes, community dwelling clinical patients, and virus risk concerns) an in-home portable force plate is a trusted and valuable data collection tool.

Impact of Extremity Manipulation on Postural Sway Characteristics: A Preliminary, Randomized Crossover Study.

OBJECTIVE: Evaluate multisegmental postural sway after upper- vs lower-extremity manipulation. METHODS: Participants were healthy volunteers (aged 21-40 years). Upper- or lower-extremity manipulations were delivered in a randomized crossover design. Postural assessments were made pre-post manipulation, in floor and rocker board conditions. Analysis included traditional balance measures of pathlength and range and sample entropy (SampEn) to examine the temporal structure of sway of the head, trunk, and surface. RESULTS: No statistical changes in pathlength or sway range on the ground surface condition were observed. No increases in the amount of sway occurred in any condition. Chiropractic manipulation of either upper or lower extremities led to reductions in traditional measures of postural control on the rocker board. In the anteroposterior direction (sagittal plane), lower-extremity manipulation led to increased trunk SampEn while on the ground, and conversely a decreased SampEn while on the rocker board. In the mediolateral rocker board condition (frontal plane), manipulation elicited a change in SampEn that differed according to site of manipulation; upper-extremity manipulation increased SampEn, whereas lower-extremity manipulation reduced SampEn. CONCLUSION: Both upper- and lower-extremity manipulation influenced several measures of postural sway on both the ground and the rocker board. Lower-extremity manipulation improved the organization of sway at the trunk (anteroposterior direction) and the board (mediolateral direction). Given the reduction and reorganization of sway metrics seen in this study, we propose extending this line of research to the elderly who are at greatest risk of increased sway and falls.

BTrackS limits of stability test is a reliable assessment of volitional dynamic postural control.

BACKGROUND: Unconstrained limits of stability assessment reveals aspects of volitional postural sway control that are inaccessible by other means. Prior versions of this assessment include instructions to sway towards predefined targets, and may not capture the full capability of the individual. RESEARCH QUESTION: This study sought to establish the test-retest reliability of a novel limits of stability protocol. METHODS: Volitional sway area was determined during unconstrained trials, where participants were instructed to explore their ability to sway towards the perimeter of their base of support. Visual feedback was provided via computer monitor. Forty healthy young adults (mean age = 20.2 ± 1.3, 15 males, 25 females) participated in this study. Trials were collected in three sessions, repeated at the same time of the same day, with one week between. Reliability was assessed using IntraClass Correlation Coefficients (ICC), considering the total area of sway as well as quadrant level area. RESULTS: Reliability was moderate between the first and second session (0.583), and much higher 0.921) between the second and third session. The quadrant level reliability was poor to excellent (0.183-0.791), with similar trends between the three sessions. SIGNIFICANCE: Ultimately, these results indicate that the novel limits of stability test is reliable. However, it is recommended that a practice trial be conducted prior to baseline establishment.

Exploring the Unmet Need for Technology to Promote Motor Ability in Children Younger Than 5 Years of Age: A Systematic Review.

OBJECTIVE: To (1) identify types of technology that promote motor ability in children younger than 5 years of age, (2) report on the type of support these devices provide, and (3) evaluate their potential for use in the community (outside of the laboratory or clinic). DATA SOURCES: A literature search of PubMed was conducted in February 2019 using specific terms, including child, rehabilitation, movement, and instrumentation. STUDY SELECTION: The search yielded 451 peer-reviewed articles, which were screened by multiple reviewers. Articles that described the use of devices for the purpose of motor rehabilitation and/or assistance (regardless of device type or body part targeted) in the age range of 0-5 years were eligible for inclusion. DATA EXTRACTION: In conformity with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, final stage data extraction consisted of full text readings where each article was reviewed twice by 3 independent reviewers. DATA SYNTHESIS: About half of the devices available (46%) for children younger than 5 years of age are orthotics and corrective casting devices. There are more facilitative (ie, power mobility devices) than inhibitive (ie, casting) technologies being used. Approximately 60% of the devices are designed for use by a single body part. Walking is the most common motor skill addressed. Although most of the devices were used to some degree outside of the laboratory or clinic, most of the devices available are considered investigative and are not available for commercial purchase. CONCLUSIONS: Many types of pediatric devices to assist movement exist, but the current scope of employed devices is limited. There is a need for developing technology that allows for, if not supports, high-dosage, early, and variable motor practice that can take place in community settings.

Orderliness of Visual Stimulus Motion Mediates Sensorimotor Coordination.

We explored the coupling of gaze and postural sway to the motion of a visual stimulus, to further understand sensorimotor coordination. Visual stimuli consisted of a horizontally oscillating red dot, moving with periodic (sine), chaotic, or aperiodic (brown noise) temporal structure. Cross Recurrence Quantification Analysis (cRQA) was used to investigate the coupling between each measured signal with the time series of the visual stimulus position. The cRQA parameter of percent determinism indicated similar strength of coupling of gaze with either periodic or chaotic motion structures, yet weaker coupling to aperiodic stimulus motion. The cRQA parameter of Maxline indicated a particular affinity toward chaotic motion. Analysis of postural coupling supports the idea that the complex periodicity of body sway affords interactivity with non-simple environmental dynamics. These results collectively strengthen the argument that chaos is an invariant and beneficial feature of biological motion, a feature which may be critical for immediate and robust coordination of the self with the environment and other environmental agents.

Training history constrains postural sway dynamics: A study of balance in collegiate ice hockey players.

BACKGROUND: Balance and postural control are integral to training and sport performance. Demands on posture are contextual and vary in different ways depending on the specific physical activity. RESEARCH QUESTION: The purpose of this study was to examine the possibility that sustained exposure to environmental constraints, through specific sport participation, might lead to a persistent modification of postural control. METHODS: Double and single-leg postural sway were compared between ice hockey players, American football players and physically active college students. Data from 30 s trials were analyzed using traditional postural sway measures of range and pathlength of the center of pressure, as well as with Sample Entropy (SEn), in both mediolateral (ML) and anteroposterior (AP) directions. RESULTS: Each group displayed unique postural sway characteristics. During single-leg stance, ice hockey players show significantly different ML pathlength and ML and AP SEn from the physically active college students (all p < 0.05), and significantly different ML and AP pathlength and AP SEn from the American football players (all p < 0.05). The American football players and the physically active college students differed for all single-legged conditions (all p < 0.05). SIGNIFICANCE: This suggests that the organization and development of postural sway is not only context dependent but also influenced by training history; supporting the idea that balance training for sport should be designed with regards to sport specific conditions.

Temporal more than spatial regulation of sway is important for posture in response to an ultra-compliant surface.

BACKGROUND AND AIM: Many people use balance training as a rehabilitation or habilitation modality. Although the time course of changes to temporal and spatial aspects of postural sway over the initial weeks of such training is as yet unclear. Particularly, we sought to explore the effects of training on sway during a dynamic task of stance on an ultra-compliant surface. Such a task provides different mechanical, and thus sensorimotor, constraints compared to stance on a solid surface. METHODS: Center of pressure (COP) was measured on an ultra-compliant surface atop a force plate at the start of each of 18 days of a 6-week balance training program. Range and standard deviation quantified amount of sway while velocity and Lyapunov exponent (LyE) quantify speed and rhythmicity of sway, respectively. RESULTS: Trend analysis indicated quadratic changes in COP range and standard deviation, with initial reductions followed by returns to initial values by the end of training. Linear reduction of movement velocity and LyE continued through the duration of the program. Reduced LyE indicates regular (self-similar) structure of the COP path. CONCLUSIONS: These results provide insight to the developing postural strategy necessary for maintaining upright stance within the dynamics created by interactions with an ultra-compliant surface. Participants showed sensitivity to surface properties, moving both more slowly and with a more regular movement pattern; suggesting that they were able to develop a more feed-forward approach to the maintenance of balance by exploiting task constraints.

Children with moderate to severe cerebral palsy may not benefit from stochastic vibration when developing independent sitting.

PURPOSE: Determine sitting postural control changes for children with cerebral palsy (CP), using a perceptual-motor intervention and the same intervention plus stochastic vibration through the sitting surface. METHODS: Two groups of children with moderate or severe CP participated in the 12 week interventions. The primary outcome measure was center of pressure data from which linear and nonlinear variables were extracted and the gross motor function measure (GMFM). RESULTS: There were no significant main effects of intervention or time or an interaction. Both treatment groups increased the Lyapunov exponent values in the medial-lateral direction three months after the start of treatment as well as their GMFM scores in comparison with baseline. CONCLUSIONS: The stochastic vibration did not seem to advance the development of sitting postural control in children between the ages of 2 and 6 years. However, perceptual-motor intervention was found beneficial in advancing sitting behavior.