Global cognition, gender, and level of education predict dual-task gait speed variability metrics in older adults.

INTRODUCTION: To determine if demographic variables and measures of cognitive function, functional mobility, self-reported balance self-efficacy, and self-reported physical activity can predict gait speed variability during single-task walking (STgscv), during cognitive-motor dual-tasking (DTgscv), and dual-task effect on gait speed variability (DTEgscv) in older adults. METHODS: In 62 older adults, demographics were recorded and cognitive function (including the Montreal Cognitive Assessment, MoCA), functional mobility, balance self-efficacy (Activity-Specific Balance Confidence Scale, ABC), and self-reported physical activity (Physical Activity Scale for the Elderly, PASE) were assessed. Three linear regression models were used to determine whether the functional mobility tests, PASE score, ABC score, and tests of cognitive function predicted gait speed variability outcomes (STgscv, DTgscv, DTEgscv), with demographics included as covariates. RESULTS: MoCA score (p = 0.003), gender (p = 0.040), and years of education (p = 0.010) significantly predicted DTgscv (R^2 = 0.297, p = 0.002). MoCA score (p = 0.008) and years of education (p < 0.001) also significantly predicted DTEgscv. Despite a significant regression model (R^2 = 0.316, p = 0.001), there were no significant individual predictors of STgscv. CONCLUSION: Older adults with lower cognitive function scores, according to the MoCA, and higher levels of education demonstrate larger gait speed variability during dual-tasking and may be at increased risk of real-world mobility issues or falling.

Real-world data capture of daily limb loading using force-sensing insoles: Feasibility and lessons learned.

Force-sensing insoles are wearable technology that offer an innovative way to measure loading outside of laboratory settings. Few studies, however, have utilized insoles to measure daily loading in real-world settings. This is an ancillary study of a randomized controlled trial examining the effect of weight loss alone, weight loss plus weighted vest, or weight loss plus resistance training on bone health in older adults. The purpose of this ancillary study was to determine the feasibility of using force-sensing insoles to collect daily limb loading metrics, including peak force, impulse, and loading rate. Forty-four participants completed a baseline visit of three, 2-minute walking trials while wearing force-sensing insoles. During month two of the intervention, 37 participants wore insoles for 4 days for 8 waking hours each day. At 6-month follow-up, participants completed three, two-minute walking trials and a satisfaction questionnaire. Criteria for success in feasibility was defined as: a) > 60 % recruitment rate; b) > 80 % adherence rate; c) > 75 % of usable data, and d) > 75 % participant satisfaction. A 77.3 % recruitment rate was achieved, with 44 participants enrolled. Participants wore their insoles an average of 7.4 hours per day, and insoles recorded an average of 5.5 hours per day. Peak force, impulse, and loading rate collected at baseline and follow-up were 100 % usable. During the real-world settings, 87.8 % of data was deemed usable with an average of 1200 min/participant. Lastly, average satisfaction was 80.5 %. These results suggest that force-sensing insoles appears to be feasible to capture real-world limb loading in older adults.

Prematriculation Predictors of Academic Difficulties During the First Year of a Doctor of Physical Therapy Program.

PURPOSE: To analyze the ability of pre-matriculation metrics to predict difficulties during the first year of a Doctor of Physical Therapy (DPT) program with a pass-fail grading system. METHODS: Undergraduate cumulative, science, and pre-requisite grade point averages (GPAs) and verbal and quantitative Graduate Record Examination (GRE) percentiles were collected during the admissions process of 190 students in an accredited DPT program at a southeastern US private university between 2019-2021. Students were dichotomized to groups with and without academic difficulties in coursework and a first-year comprehensive assessment (CA). Independent t-tests identified differences between groups, and logistic regression analyses identified predictors of academic difficulties. Receiver operating characteristic (ROC) curve analyses were performed to identify cut-off scores and risk ratios were calculated. RESULTS: Students with coursework difficulties had lower verbal (d=0.36, p=0.009) and quantitative (d=0.31, p=0.02) GRE scores. Verbal GRE scores were also lower in students who failed the CA (p=0.049). Students who scored less than the 47th percentile on the verbal GRE were 53% more likely to have academic difficulties and 4.2 times more likely to fail the CA than those who scored in the 70th percentile or higher. CONCLUSION: Verbal GRE percentile best predicted academic difficulty in the first year of a DPT program.

Maximal daily stepping cadence partially explains functional capacity of individuals with end-stage knee osteoarthritis.

BACKGROUND: Individuals with end-stage knee osteoarthritis (OA) walk at a lower intensity (ie, slower step cadence) contributing to worse physical function. Previous literature reports daily step counts and sedentary time, with little information regarding stepping bouts or cadence. Determining relationships between daily higher stepping cadence duration and clinical outcomes can move the field toward optimal daily stepping prescription. OBJECTIVE: To quantify daily physical activity patterns of individuals with end-stage knee OA and determine the contribution of high stepping cadence to explain functional capacity variability. DESIGN: Cross-sectional analysis. SETTING: Veterans Administration medical center. PARTICIPANTS: U.S. military veterans (n = 104; age: 67.1 years [7.2]; mean [SD]; male [89.3%]) with end-stage knee OA were enrolled. INTERVENTION: Not applicable. MAIN OUTCOME MEASURE: Functional capacity (6-Minute Walk Test [6MWT]). Physical activity (activPAL wearable sensor; cadence and time sitting, standing, and stepping), pain (Western Ontario and McMaster Universities Osteoarthritis Index-pain subscale) sociodemographic variables, and comorbidities (body mass index and Functional Comorbidity Index) are the main explanatory variables. RESULTS: Participants' wake time was mainly sitting (11.0 h/day) in ≥60-minute bouts (29.7% ± 12.7 of sitting time). Standing (3.4 hours/day) and stepping (1.4 h/day) primarily occurred in 0-5 minute bouts (standing: 87.7% ± 14.4 of standing time, stepping: 98.7% ± 12.7 of stepping time) and stepping cadence was predominantly incidental (1-19 spm; 52.9% ± 9.6 of total stepping time). Backward elimination model results indicated shorter medium-to-brisk cadence bout duration, older age, and higher pain significantly explained shorter 6MWT distance (Adj R2 =0.24, p < .01). CONCLUSIONS: Individuals with knee OA spend most of their waking hours sitting, while standing and stepping occurs in short bouts at very low stepping cadence. Decreased time in high stepping cadence is associated with lower functional capacity. Future studies should explore if increasing the daily time spent in higher step cadence can improve functional capacity in this population.

Offloading of Diabetic Neuropathic Plantar Ulcers: Secondary Analysis of Step Activity and Ulcer Healing.

OBJECTIVE: Although it is well-known that offloading devices facilitate healing in people with diabetes and neuropathic plantar ulcers, little is known about how step activity affects healing. The purposes of this study were to compare: (1) healing outcomes (time to healing, percentage of ulcers healed); (2) healing rates by ulcer location; and (3) step activity (daily step count, daily peak mean cadence) among patients using either total contact casts (TCCs) or removable cast walker boots (RCWs). METHODS: The study included 55 participants (TCC, 29; RCW, 26) with diabetes mellitus, peripheral neuropathy, and a Wagner grade 1 or 2 neuropathic plantar ulcer. Each participant wore an activity monitor for 14 consecutive days. Step activity and healing variables were assessed using independent t tests, Kruskal-Wallis, Kaplan-Meier, and Mantel-Cox log-rank tests. RESULTS: Mean participant age was 55 (SD, 11) years. The percentage of ulcers healed was lower in the RCW group versus the TCC group (65% vs 93%). If healed, average healing rate was 77 (SD, 48) days in the TCC group and 138 (SD, 143) days in the RCW group. Survival distribution by ulcer location was different for RCW forefoot than other locations (132 ± 13 days vs 91 ± 15, 75 ± 11, and 102 ± 36 days for TCC forefoot, TCC-midfoot/hindfoot, and RCW-midfoot/hindfoot, respectively; χ2 = 10.69, P = .014). Average step count was 2,597 in the RCW group versus 1,813 steps in the TCC group (P = .07). The daily peak mean cadence for 20-, 30-, or 60-minute periods was greater with RCW use. CONCLUSIONS: Step activity in participants with RCWs was increased compared with those with TCCs. Because of their potential to be easily removable, RCWs may impair ulcer healing by allowing greater step activity.

The effect of exercise, physical activity, stepping characteristics, and loading on diabetic foot ulcer healing: a systematic review.

The aim of this review was to investigate the effect of exercise, physical activity, stepping characteristics, and loading on DFU healing. A systematic review using proprietary software and a PRISMA 2020 checklist was performed by searching MEDLINE, ProQuest, Scopus, CINAHL, Ovid, and the Cochrane Library for eligible articles from 1960 to December 2020. The primary outcome was time to wound closure. Other outcomes included percentage of DFU healed and time to percentage reduction in DFU. Of the 9 articles included, 6 addressed step activity during the off-loading phase of healing and 3 investigated the addition of NWB exercise on wound healing. Reduced loading via lower daily step activity, less standing duration, and shorter walking bouts in combination with wearing an off-loading device facilitated more rapid wound healing. Exercise seemed to facilitate more rapid healing, as well. Reduced limb loading via daily activity and use of offloading devices improved DFU healing rates. Additional research is necessary to determine the optimal thresholds for exercise, activity, step characteristics, and loading to improve healing outcomes in persons with DFU.

Clinical utility of the Trendelenburg Test in people with multiple sclerosis.

BACKGROUND: The clinical utility of the Trendelenburg Test remains unknown in people with multiple sclerosis (MS). OBJECTIVE: To measure (1) intra-rater reliability, (2) agreement of goniometer-assessed Trendelenburg pelvis-on-femur angle (POF) with motion capture, and (3) concurrent validity of Trendelenburg POF and hip abduction strength with POF during walking and step negotiation. METHODS: Trendelenburg POF was measured in 20 people with MS using goniometry and motion analysis. In addition, peak POF was measured using motion analysis during walking, step ascent, and step descent. Intra-rater reliability of goniometer-assessed Trendelenburg POF and agreement with motion analysis-assessed POF were analyzed. Pearson's r was used to determine the relationships between Trendelenburg POF and hip abduction strength with peak POF during each functional activity. RESULTS: Goniometer-assessed Trendelenburg POF demonstrated very strong reliability (ICC: 0.948), strong agreement with 3D motion analysis (ICC: 0.792), correlated moderately with peak POF during walking (r = 0.519) and step ascent (r = 0.572), and weakly with step descent (r = 0.463). Hip abductor strength correlated weakly with peak POF during step ascent (r = -0.307) and negligibly during walking (r = -0.270) and step descent (r = -0.249). CONCLUSIONS: Goniometer-assessed Trendelenburg POF was reliable, agreed with motion analysis, and may provide insight into hip abduction muscle performance during functional activities in people with MS.

Including cognitive assessments with functional testing predicts capabilities relevant to everyday walking in older adults.

BACKGROUND: Dual-task (DT) testing reflects real-world walking demands in older adults but is not always feasible to perform in clinic. Whether clinical measures that predict single-task (ST) performance also predict DT performance or dual-task effects (DTEs) has not been fully explored. RESEARCH QUESTION: What are the relationships between cognitive performance, functional mobility, and self-reported physical activity and balance confidence and ST and DT Gait Speed and Cognitive Reaction Time, as well as DTEs on Gait Speed (DTEGS) and Cognitive Reaction Time (DTERT), in older adults? METHODS: Sixty-two older adults (71.5 ± 7.1 years, 17 males) completed cognitive performance, functional mobility, and self-report physical activity and balance confidence assessments. Three 1-min trials were performed: 1) ST Cognition (clock task), 2) ST Gait and 3) DT Cognition + Gait, with Cognitive Reaction Time (recorded during clock task performance via DirectRT) and Gait Speed (measured during walking trial via APDM system) recorded, and DTEGS and DTERT calculated, as the cognitive and gait outcomes. Six multivariate regressions were conducted to test whether cognitive performance, functional mobility, and self-report assessments predicted Gait Speed and Cognitive Reaction Time in ST and DT conditions and DTEs. RESULTS: The Comprehensive Trail Making Test (CTMT) predicted Reaction Time in ST cognitive (ß = - 0.525, p = .003) and DT (ß = - 0.510, p = .006) trials. The Physical Activity Scale for the Elderly (PASE) predicted DTERT (ß = - 0.397, p = .008). The 10-Meter Walk Test (10MWT) predicted Gait Speed in ST gait (ß = 0.692, p < .001) and DT (ß = 0.715, p < .001) trials. The Four Square Step Test (FSST) predicted ST Gait Speed (ß = - 0.233, p = .034). The Montreal Cognitive Assessment (MoCA) (ß = 0.293, p = .027), 10MWT (ß = 0.322, p = .046), and the FSST (ß = 0.378, p = .019) predicted DTEGS. SIGNIFICANCE: The 10MWT, CTMT, and MoCA can be easily implemented in the clinic and may be good choices to assess cognitive and functional abilities necessary for ambulation in older adults.

Feasibility of repeated session error-augmentation gait training for people with nontraumatic transtibial amputation.

BACKGROUND: Spatiotemporal gait asymmetries are a persistent problem for people with non-traumatic lower-limb amputation. To date, there is limited knowledge of multi-session gait training interventions targeting step length symmetry after non-traumatic amputation. OBJECTIVE: The objective was to evaluate the feasibility and efficacy of an eight-session, treadmill-based error-augmentation gait training (EAT) protocol to improve spatiotemporal gait asymmetry in people with non-traumatic transtibial amputation (TTA). STUDY DESIGN: Pre-post, single group. Methods: The EAT protocol involved eight training sessions (twice per week, four weeks) of supervised split-belt treadmill walking with asymmetrical belt speeds for five, three-minute sets each session. Step length symmetry during overground walking at a self-selected gait speed was assessed prior to, weekly, and one-week after the EAT protocol. Feasibility outcomes included protocol fidelity, safety, participant acceptability, and efficacy. RESULTS: Seven of the eight participants (87.5%) completed the intervention at the prescribed dose. One participant developed a skin blister on their residual limb, which was possibly related to the intervention. No falls, musculoskeletal injuries, or increases in pain occurred. Participants rated EAT as acceptable based on scores on the Intrinsic Motivation Inventory - Interest/Enjoyment subscale (6.6 ± 0.5; mean ± SD). Average between-limb step length Normalized Symmetry Index improved (was reduced) one-week following EAT (2.41 ± 6.6) compared to baseline (5.47 ± 4.91) indicating a moderate effect size (d=0.53). CONCLUSIONS: An eight session EAT program delivered over four weeks using a split-belt treadmill is feasible for people with unilateral non-traumatic TTA and may reduce step length asymmetry up to a week after intervention.

The Validity of the Single-Leg Heel Raise Test in People With Multiple Sclerosis: A Cross-Sectional Study.

Background: The single-leg heel raise test is a common clinical assessment; however, little is known about its validity in people with multiple sclerosis (MS). This study investigated the validity of the single-leg heel raise test in a group of people with MS and a healthy control group (CTL). Materials and Methods: Twenty-one people with MS (49 ± 12 years, Expanded Disability Status Scale 1.5-5.5) and 10 healthy controls (48 ± 12 years) performed the single-leg heel raise test, ankle plantarflexion isometric strength assessment using electromechanical dynamometry, and mobility measures (Timed 25-Foot Walk, 2-Min Walk Test, Functional Stair Test). Results: Convergent validity between the heel raise test and strength was moderate for participants with MS completing <20 heel raises (r = 0.63, p = 0.001) but weak for the entire sample (r = 0.30, p = 0.020). Compared to the average CTL group values, the heel raise test differentiated between groups on the MS groups' weaker (p < 0.001) and stronger (p = 0.003) limbs, while strength only differentiated between groups on the weaker limb (p = 0.010). Considering the weaker and strong limbs from the MS group and the CTL group average values, the mobility measures had moderate-to-strong correlations with the heel raise test on the weaker MS limb + CTL (r = 0.71-0.78) and stronger MS limb + CTL (r = 0.62-0.70), and weak-to-moderate correlations with strength on the weaker MS limb + CTL (r = 0.49-0.58, p = 0.001-0.007). Discussion: In people with MS, the single-leg heel raise test may be clinically useful as it identified impaired muscle performance and differentiated muscle performance from a healthy control group and, together with the control group, correlated with functional mobility.

Error-Manipulation Gait Training for Veterans With Nontraumatic Lower Limb Amputation: A Randomized Controlled Trial Protocol.

OBJECTIVE: he purpose of this study will be to determine the efficacy of error-manipulation gait training (error-augmentation or error-correction) to improve step length symmetry and secondary health outcomes in veterans with unilateral nontraumatic transtibial amputation (TTA). METHODS: This will be a 3-arm, parallel, assessor-blinded, randomized controlled trial, with baseline, postintervention, and 3-month follow-up assessments in a VA Geriatric Research Education and Clinical Center. Participants are 54 US military veterans ranging in age from 50 to 85 years with a unilateral transtibial nontraumatic amputation. Participants will be randomized into 1 of 3 groups: error-augmentation training (EAT), error-correction training (ECT), or supervised walking (CTL). Each group will complete 8 split-belt treadmill walking training sessions of 25 minutes each over 4 weeks. The EAT group will walk with belts moving at asymmetrical speeds. The ECT group will walk to the cadence of a metronome and the split belts moving at symmetrical speeds. The CTL group will walk with symmetrical belt speeds and without feedback. Step length symmetry is the primary outcome and will be assessed using an asymmetry index during overground walking. Secondary outcomes include lower extremity joint work during treadmill walking, 6-Minute Walk Test performance, daily step count, participant-perceived disability, and residual-limb integumentary health. Outcomes will be assessed at preintervention, 1-week postintervention (primary endpoint), and 13 weeks postintervention. IMPACT: This study protocol focuses on an understudied area of rehabilitation for patients with nontraumatic unilateral TTA who have high levels of spatiotemporal gait asymmetry and mobility impairment. The results of this study will inform future implementation of clinical gait training interventions to improve spatiotemporal gait symmetry and long-term health and disability outcomes in patients with nontraumatic unilateral TTA.

Movement compensations during a step ascent task are associated with stair climbing performance in people with multiple sclerosis.

BACKGROUND: The biomechanical mechanisms underlying stair climbing limitations are poorly understood in people with multiple sclerosis (MS). RESEARCH QUESTIONS: Are trunk and pelvis motion and lower extremity joint moments during step ascent different between MS and control groups? Are step ascent biomechanics and stair climbing performance associated in people with MS? METHODS: 20 people with MS (49 ±â€¯12 years, EDSS range: 1.5-5.5) and ten control participants (48 ±â€¯12 years) underwent three-dimensional motion analysis while ascending a 15.2-cm step and also completed a timed Functional Stair Test. Main effects of group (MS vs Control) and limb (Stronger/Dominant vs Weaker/Non-dominant) and interactions were assessed using two-way analyses of variance. Associations between movement patterns during the step ascent and Functional Stair Test performance were performed using Pearson's correlations and backward stepwise linear regression. RESULTS: Significant group main effects were observed in greater sagittal pelvis excursion (p < 0.001), greater sagittal (p = 0.013) and frontal (p = 0.001) trunk excursion, and lower trail limb peak ankle plantar flexion moment (p < 0.001) of the MS group. Significant limb main effects were observed with greater sagittal trunk excursion (p = 0.037) and peak trail limb ankle plantar flexion moment (p = 0.037) in the stronger/dominant limb. A significant interaction was observed in peak knee extensor moment (p = .002). Stair climbing performance in the MS group correlated with sagittal (r = .607, p=<0.001) and frontal pelvis excursions (r = 0.385, p = 0.014), sagittal trunk excursion (r = .411, p = 0.008), and ankle plantar flexion moments (r=-0.415, p = 0.008). Sagittal and frontal pelvis excursion and bilateral handrail use explained a significant amount of variability in stair climbing performance (Adj R2 = 0.775). SIGNIFICANCE: In conclusion, despite the presence of proximal and distal lower extremity movement pattern compensations during a step ascent task, larger pelvis angular excursions are associated with impaired stair climbing performance in people with MS and may serve as targets for future rehabilitation interventions.

Patterns of Sitting, Standing, and Stepping After Lower Limb Amputation.

OBJECTIVE: The objectives of this study were to describe sitting, standing, and stepping patterns for people with lower limb amputation (LLA) and to compare sitting, standing, and stepping between people with dysvascular LLA and people with traumatic LLA. METHODS: Participants with dysvascular or traumatic LLA were included if their most recent LLA was at least 1 year earlier, they were ambulating independently with a prosthesis, and they were between 45 and 88 years old. Sitting, standing, and stepping were measured using accelerometry. Daily sitting, standing, and stepping times were expressed as percentages of waking time. Time spent in bouts of specified durations of sitting (<30, 30-60, 60-90, and >90 minutes), standing (0-1, 1-5, and >5 minutes), and stepping (0-1, 1-5, and >5 minutes) was also calculated. RESULTS: Participants (N = 32; mean age = 62.6 [SD = 7.8] years; 84% men; 53% with dysvascular LLA) spent most of the day sitting (median = 77% [quartile 1 {Q1}-quartile 3 {Q3} = 67%-84%]), followed by standing (median = 16% [Q1-Q3 = 12%-27%]) and stepping (median = 6% [Q1-Q3 = 4%-9%]). One-quarter (median = 25% [Q1-Q3 = 16%-38%]) of sitting was accumulated in bouts of >90 minutes, and most standing and stepping was accrued in bouts of <1 minute (standing: median = 42% [Q1-Q3 = 34%-54%]; stepping: median = 98% [Q1-Q3 = 95%-99%]). Between-etiology differences included proportion of time sitting (traumatic: median = 70% [Q1-Q3 = 59%-78%]; dysvascular: median = 79% [Q1-Q3 = 73%-86%]) and standing (traumatic: median = 23% [Q1-Q3 = 16%-32%]; dysvascular: median = 15% [Q1-Q3 = 11%-20%]). CONCLUSION: Participants had high daily volumes of long durations of sitting. Further, these individuals accumulated most physical activity in bouts of <1 minute. IMPACT: High levels of sedentary behavior and physical inactivity patterns may place people with LLA at greater mortality risk relative to the general population. Interventions to minimize sedentary behaviors and increase physical activity are potential strategies for improving poor outcomes of physical therapy after LLA.

Movement asymmetry during low and high demand mobility tasks after dysvascular transtibial amputation.

BACKGROUND: Movement asymmetries between lower limbs are commonly exhibited by adults after transtibial amputation. However, the degree of movement asymmetry between low- and high-demand functional tasks remains unknown. METHODS: Kinematic and kinetic data were collected during overground walking (low-demand) and step ascent (high-demand) tasks for two groups: 1) persons with transtibial amputation and 2) healthy matched peers. Analysis of covariance was used to compare sagittal-plane peak knee moment and joint angle (primary) and hip and ankle moments and joint angles, vertical ground reaction force and impulse (secondary). FINDINGS: Within transtibial amputation group comparisons showed significantly greater between-limb asymmetry in peak knee moment (p < .01), vertical impulse (p < .01), peak vertical ground reaction force (p = .05), peak ankle angle (p < .01) and peak ankle moment (p < .01) with the step ascent task compared to overground walking. The transtibial amputation group had greater between-limb asymmetry during step ascent in peak knee moment (p < .01), vertical impulse (p < .01), peak vertical ground reaction force (p = .04) and peak ankle angle (p < .01) than healthy matched peers. During overground walking, the transtibial amputation group had greater between-limb asymmetry in peak vertical impulse (p = .05) and peak ankle moment (p < .01) than healthy matched peers. INTERPRETATION: Movement asymmetry is increased during step ascent compared to overground walking for adults with transtibial amputation. While the restoration of overground walking is the focus of post-amputation rehabilitation and prosthetic design, higher demand tasks should also be considered to maximize mobility for adults with transtibial amputation.

Step length symmetry adaptation to split-belt treadmill walking after acquired non-traumatic transtibial amputation.

BACKGROUND: Between-limb step length asymmetry is common following transtibial amputation (TTA) and contributes to negative health consequences. There are limited evidence-based interventions targeting reduced gait asymmetry for people with TTA. Split-belt treadmill walking with asymmetrical belt speeds has successfully reduced gait asymmetry in other patient populations. However, individuals with non-traumatic TTA have critical health-related impairments that may influence the ability to respond to split-belt treadmill walking. RESEARCH QUESTION: Do people with acquired, non-traumatic TTA adapt and retain a more symmetrical gait pattern in response to split-belt treadmill walking? METHODS: Step length asymmetry was measured during split-belt treadmill walking. Eight participants walked under two alternating belt speed conditions: symmetrical (3 sets; Baseline, TIED1, TIED2) and asymmetrical belt speeds (5 sets; SPLIT1-5). One-way repeated-measures ANOVA with post-hoc Tukey's HSD tests were used to assess adaptation and short-term retention of step length symmetry. Adaptation was assessed as the level of asymmetry during TIED walking following repeated exposure to SPLIT walking. Retention was measured as the change in level of asymmetry during each set of SPLIT walking. RESULTS: Significant adaptation to split-belt walking was observed from late Baseline to early TIED1 and early TIED2. Between-limb step length asymmetry decreased from late Baseline (5.3 ±â€¯3.4) to early TIED1 (-9.4 ±â€¯3.6) and this change was sustained between early TIED1 and early TIED2 (-11.2 ±â€¯3.1) (ANOVA F = 73.043, p < .001). Adaptations were retained as step length asymmetry decreased from early SPLIT1 (48.5 ±â€¯5.3) to early SPLIT3 (31.4 ±â€¯3.5) to early SPLIT5 (23.9 ±â€¯5.1) (ANOVA F = 35.284, p < .001). SIGNIFICANCE: Individuals with non-traumatic TTA are capable of gait adaptation to split-belt walking and short-term retention of adaptations after removal of the asymmetrical belt speeds. Adaptability of step length symmetry is possible without modification to the prosthetic limb. Split-belt walking should be tested as a potential intervention to help people with acquired, non-traumatic TTA increase between-limb step symmetry.

Biobehavioral Intervention Targeting Physical Activity Behavior Change for Older Veterans after Nontraumatic Amputation: A Randomized Controlled Trial.

BACKGROUND: Lower-limb amputation (LLA) due to non-traumatic vascular etiology is linked to extremely low physical activity and high disability. OBJECTIVE: To test the feasibility of a biobehavioral intervention designed to promote physical activity. DESIGN: A randomized, single-blind feasibility trial with a crossover design. SETTING: Veterans Administration Medical Center. PARTICIPANTS: Military veterans (age: 65.7 [7.8] years; mean [standard deviation]) with nontraumatic lower-limb amputation (LLA), randomized to two groups: GROUP1 (n = 16) and GROUP2 (n = 15). Both groups had similar baseline amputation characteristics (level of amputation and time since amputation). INTERVENTIONS: Twelve weekly, 30-minute telehealth sessions of physical activity behavior-change intervention, with GROUP1 participating in weeks 1-12 and GROUP2 in weeks 13-24. GROUP1 noncontact phase in weeks 13-24 and GROUP2 attention control telehealth phase in weeks 1-12. MAIN OUTCOME MEASURES: Feasibility (participant retention, dose goal attainment, intervention acceptability [Intrinsic Motivation Inventory [IMI] Interest and Enjoyment scale], safety) and signal of efficacy (free-living physical activity [accelerometer-based average daily step count], Late Life Function and Disability Index - Disability Scale [LLFDI-DS]). RESULTS: Participant retention rate was high (90%), with three participants lost to follow-up during the intervention period. Dose goal attainment was low, with only 10% of participants achieving an a priori walking dose goal. Intervention was rated as acceptable, with mean IMI Interest and Enjoyment score (5.8) statistically higher than the null value of 5.0 (P = .002). There were no between-group differences in adverse event rates (falls: P = .19, lower extremity wounds: P = .60). There was no signal of efficacy for change in average daily step count (d = -0.15) or LLFDI-DS (d = -0.22 and 0.17 for frequency and limitations scales, respectively). CONCLUSIONS: Telehealth delivered biobehavioral intervention resulted in acceptable participant retention, low dose goal attainment, high participant acceptability, and low safety risk, while having no signal of efficacy (physical activity, disability) for people with nontraumatic LLA.

Step descent strategy is altered bilaterally despite unilateral muscle strength impairment after total knee arthroplasty.

PURPOSE: Muscle weakness and difficulty descending stairs are common after unilateral total knee arthroplasty (TKA), but the relationship between each is unclear. The purpose of this study was to compare lower extremity muscle strength, lower extremity support moments during step descent, and assess relationships between each. METHODS: The study included 40 subjects (20 post-TKA, 20 control). Knee extensor, hip abductor, and hip external rotator strength were measured and biomechanical analyses of step descent performed. Patients with TKA were assessed 3 and 6 months post-surgery. RESULTS: At 3 and 6 months post-TKA, operated limb hip external rotator and knee extensor strength were impaired compared to the non-operated limb (p < 0.01); however, no between-limb differences were observed during step descent. Compared to the control group, hip external rotator and knee extensor strength, total lower extremity support moment, and knee support moment during step descent were impaired post-TKA (p < 0.05). At 6 months post-TKA, knee extensor and hip external rotator strength correlated with total support moment during step descent (rs = 0.40, 0.41, p < 0.02). Hip abductor and external rotator strength negatively correlated with knee support moment during step descent (rs = - 0.35, - 0.39, p < 0.03). CONCLUSIONS: Persistent operative limb knee extensor and hip external rotator muscle weakness are noted following unilateral TKA. Despite unilateral weakness, bilateral alterations in step descent strategy occur following TKA. Patients with TKA utilize hip musculature to reduce knee muscle demand during step descent, possibly contributing to limitations in long-term step descent performance.

Error-augmentation gait training to improve gait symmetry in patients with non-traumatic lower limb amputation: A proof-of-concept study.

BACKGROUND: Asymmetrical stepping patterns are chronic gait impairment for individuals with non-traumatic lower limb amputation. Persistent gait asymmetries contribute to poor gait efficiency, decreased physical function, and development of secondary orthopedic conditions. OBJECTIVES: Evaluate the feasibility and preliminary responsiveness of a treadmill-based, error-augmentation gait training protocol to improve gait symmetry in patients with non-traumatic transtibial amputation. STUDY DESIGN: Single group, pre- and post-test. METHODS: The error-augmentation gait training protocol involved walking on a split-belt treadmill with asymmetrical belt speeds for five 3-min sets. Spatiotemporal gait characteristics during overground walking at self-selected and fast walking speeds were assessed prior to, immediately after, and 20 min following the error-augmentation gait training protocol. Outcomes included practicality, implementation feasibility, safety, participant acceptability, and change in gait asymmetry. RESULTS: All four participants completed the error-augmentation gait training protocol as prescribed, without adverse events, and found the intervention to be acceptable. Step length and stance time asymmetry during overground walking changed immediately following the error-augmentation gait training protocol with inconsistent changes retained after a 20 min washout period. CONCLUSIONS: A single session of error-augmentation gait training is a feasible and safe intervention to modify gait asymmetry in patients with non-traumatic transtibial amputation. Additional study with larger sample sizes and repeated error-augmentation gait training dosing are warranted. CLINICAL RELEVANCE: Gait training using error-augmentation on a split-belt treadmill may modify step length and stance time asymmetry for patients with non-traumatic transtibial amputation, but additional research is needed regarding short- and long-term efficacy. Additional training sessions may be needed to sustain initial changes achieved from a single session.

Physical Function and Pre-Amputation Characteristics Explain Daily Step Count after Dysvascular Amputation.

BACKGROUND: People with dysvascular lower limb amputation (LLA) achieve one-third of the recommended steps per day and experience severe disability. Although physical function improves with rehabilitation after dysvascular LLA, physical activity remains largely unchanged, and factors contributing to limited daily step count are unknown. OBJECTIVES: To identify factors that contribute to daily step count after dysvascular LLA. DESIGN: Cross-sectional, secondary data analysis. SETTING: Outpatient rehabilitation facilities. PARTICIPANTS: Fifty-eight patients with dysvascular major LLA (age: 64 ± 9 years, body mass index: 30 ± 8 kg/m2 , male: 95%, transtibial LLA: 95%). METHODS: Data were collected by a blinded assessor after dysvascular LLA. Candidate explanatory variables included (1) demographics, (2) LLA characteristics, (3) comorbidities and health behaviors, and (4) physical function. Variables with univariate associations with log steps/day (transformed due to non-normality) were included in a multiple linear regression model using backward elimination to identify factors that explained significant variability in log steps/day. PRIMARY OUTCOME MEASURE: The primary outcome, daily step count, was measured with accelerometer-based activity monitors worn by participants for 10 days. RESULTS: Participants took an average (± SD) of 1450 ± 1309 steps/day. After backward elimination, the final model included four variables explaining 62% of the overall daily step count (P < .0001): 2-minute walk distance (32%), assistive device use (11%), cardiovascular disease (10%), and pre-amputation walking time (11%). CONCLUSIONS: Average daily step count of 1450 steps/day reflects the lowest category of sedentary behavior. Physical function, cardiovascular disease, and pre-amputation walking time explain 62% of daily step count after dysvascular LLA. Although physical rehabilitation commonly focuses on improving physical function, interventions to increase daily step count after dysvascular LLA should also consider chronic disease and health behaviors that predate LLA. LEVEL OF EVIDENCE: III.

Rate of torque development is the primary contributor to quadriceps avoidance gait following total knee arthroplasty.

BACKGROUND: Following rehabilitation for total knee arthroplasty, "quadriceps avoidance gait", defined by limited knee flexion angle excursion during walking, persists and contributes to poor long-term outcomes. Given the presence of several post-surgical impairments, identifying the contribution of multiple factors to knee flexion angle excursion is important to developing targeted interventions to improve recovery after total knee arthroplasty. RESEARCH QUESTIONS: Which outcomes continue to improve following rehabilitation for total knee arthroplasty? What are the primary contributors to impaired knee flexion angle excursion during walking following total knee arthroplasty? METHODS: Peak muscle strength and rate of torque development of the quadriceps, hip abductors, and hip external rotators, five-time sit-to-stand test, Knee Injury & Osteoarthritis Outcome Score, and gait mechanics were assessed in 24 participants at three and six months post-surgery. Paired sample t-tests or Wilcoxon Signed-Rank tests were used to compare outcomes between assessments. Stepwise multiple linear regression were used to assess the contribution of each measure to knee flexion angle excursion. RESULTS: Significant improvements were noted in all outcomes except hip external rotation rate of torque development, gait speed, and knee flexion angle excursion. Quadriceps rate of torque development and knee pain significantly contributed to knee flexion angle excursion at three months (Adjusted R2 = 0.342), while quadriceps rate of torque development and peak hip external rotation strength significantly contributed at six months (Adjusted R2 = 0.436). SIGNIFICANCE: While higher pain levels at three months and greater peak hip external rotation muscle strength at six months contribute to impaired knee flexion angle excursion, quadriceps rate of torque development was the primary contributor to knee flexion angle excursion at both three and six months after surgery. Implementing strategies to maximize quadriceps rate of torque development during rehabilitation may help to reduce quadriceps avoidance gait after total knee arthroplasty.