Effects of age and knee osteoarthritis on the modular control of walking: A pilot study

Background Older adults and individuals with knee osteoarthritis (KOA) often exhibit reduced locomotor function and altered muscle activity. Identifying age- and KOA-related changes to the modular control of gait may provide insight into the neurological mechanisms underlying reduced walking performance in these populations. The purpose of this pilot study was to determine if the modular control of walking differs between younger and older adults without KOA and adults with end-stage KOA. Methods Kinematic, kinetic, and electromyography data were collected from ten younger (23.5 ± 3.1 years) and ten older (63.5 ± 3.4 years) adults without KOA and ten adults with KOA (64.0 ± 4.0 years) walking at their self-selected speed. Separate non-negative matrix factorizations of 500 bootstrapped samples determined the number of modules required to reconstruct each participant’s electromyography. One-way Analysis of Variance tests assessed the effect of group on walking speed and the number of modules. Kendall rank correlations (τb) assessed the association between the number of modules and self-selected walking speed. Results The number of modules required in the younger adults (3.2 ± 0.4) was greater than in the individuals with KOA (2.3 ± 0.7; p = 0.002), though neither cohorts’ required number of modules differed significantly from the unimpaired older adults (2.7 ± 0.5; p ≥ 0.113). A significant association between module number and walking speed was observed (τb = 0.350, p = 0.021) and individuals with KOA walked significantly slower (0.095 ± 0.21 m/s) than younger adults (1.24 ± 0.15 m/s; p = 0.005). Individuals with KOA also exhibited altered module activation patterns and composition (which muscles are associated with each module) compared to unimpaired adults. Conclusion These findings suggest aging alone may not significantly alter modular control; however, the combined effects of knee osteoarthritis and aging may together impair the modular control of gait.

Effects of Auditory Stimuli on Beat-Synchronized Long Distance Walking: Part A - Energize on Country Music

In well documented studies, walking and music have independently shown substantial medical, health, productivity, and other human benefits. When music is combined with walking, and especially when the walking is done in synchrony to the beat, the music can stimulate faster walking without apparent awareness, the “velocity effect”. Some studies have reported that music that is either familiar, more enjoyable, and/or has higher “groove” tends to be more stimulating, and that some music can actually be sedating resulting in a slower speed relative to that of walking to a metronome at the same cadence. Research illuminating the velocity effect has mostly been conducted over relatively short stepping distances in a laboratory or similar outdoor setting. The current study examines walking on a real-world long distance outdoor track with a single genre of music that was at least somewhat familiar and somewhat enjoyable to the test subject. In this study, the test subject stepped in self-instructed synchrony with confirmed high accuracy to two types of auditory stimuli – either to the beat of a metronome (a presumed neutral source or what might be considered a most rudimentary form of music), or to the beat of a broad-spectrum of country music continuously over a 2-mile course. Nine metronome tempos and twenty-one country music tempos were examined in a walkable range of 90 to 130 beats per minute (BPM), and the effects of the music and metronome on walking performance were examined and quantified. Overall, the mix of country music was significantly more energizing than the metronome providing a relatively consistent 10% increase in step length and a resulting 10% increase in speed over the entire tempo/cadence range. Speed as a function of tempo was essentially linear in the beat range for both auditory stimuli with an apparent increase in speed relative to the trendlines occurring near 120 BPM, a preferred human response frequency reported in some prior investigations.

Effects of Age on Dual Task Walking Performance as Measured Using a Smartphone Application in Middle-Aged Adults

After the age of 65, one’s ability to walk while performing an additional cognitive task (i.e., dual-tasking) is predictive of both future falls and cognitive decline. However, while it is well-known that older adults exhibit diminished dual-task performance, the time course of age-related dual-task decline has not been established. We thus conducted an analysis of data collected within the ongoing Barcelona Brain Health Initiative, a prospective population-based study characterizing the determinants of brain health maintenance in middle-aged adults. Cognitively-unimpaired participants (n=655) aged 40-65 years without neuro-psychiatric disease completed laboratory-based trials of walking normally (single-task) and walking while performing a verbalized serial subtraction task (dual-task). A smartphone-based gait assessment application was used to capture data and derive both the mean stride time (ST) and stride time variability (STV, defined as the coefficient of variation about the mean stride time) of each trial. The dual-task costs (DTC) to each gait metric were obtained by calculating the percent change from single- to dual-task conditions. We categorized participants into five groups according to age (e.g. Group 1: 40-45 years; Group 5: 60-65 years). Age group did not have an effect on single-task gait outcomes (p>0.51). However, the oldest age group, as compared to each of the other groups, exhibited greater DTC to both ST and STV (p<0.03). These results indicate that dual-task walking performance in particular may begin to diminish in late middle age even in the absence of detectable cognitive issues, DTC may offer a sensitive metric to age-related change in cognitive function.

Physical Activity Impacts Walking Distances and Energy Consumption of Patients with Peripheral Artery Disease

Lower extremity peripheral artery disease (PAD) is attributed to buildup of atherosclerotic plaques preventing adequate blood flow, leading to pain during walking, and ultimately physical inactivity. Normal day-to-day levels of physical activity may impact the distance a subject can walk before claudication pain onset, as well as their energy consumption capabilities. This study compared walking performance (initial claudication distance (ICD) and absolute claudication distance (ACD)), and energy consumption (EC) between active and inactive subjects with PAD. The distinction between groups was made using previous research that declared the average PAD patient walks 3586 steps/day. Ten subjects were classified as active (□3586 average steps/day) and sixteen participants as inactive (<3586 steps/day) based on a 7-day accelerometer measurement. The Gardner progressive treadmill test was used to asses ICD, ACD, and EC. EC was measured using a metabolic cart and calculated from the second minute of walking and the last minute prior to stopping due to claudication pain. The average ICD and ACD for the active group were 130.6±106.7 meters and 306.0±184.7 meters, respectively and 143.8±119.0 meters and 248.0±156.0 meters, respectively for the inactive group. The average EC for the second minute and last minute were 9.6±1.9 mlkg-1min-1 and 11.5±2.4 mlkg-1min-1 respectively for active group and 7.0±3.1 mlkg-1min-1 and 8.1±3.8 mlkg-1min-1 respectively for inactive group. The data suggests that the active group had better walking performance and greater energy consumption indicating increased efficiency of oxygen transport and extraction capability in the leg muscles.

Cerebellar Theta Burst Stimulation on Walking Function in Stroke Patients: A Randomized Clinical Trial

Objectives: The objective of this study was to explore the efficacy of cerebellar intermittent theta burst stimulation (iTBS) on the walking function of stroke patients.Methods: Stroke patients with walking dysfunction aged 25–80 years who had suffered their first unilateral stroke were included. A total of 36 patients [mean (SD) age, 53 (7.93) years; 10 women (28%)] were enrolled in the study. All participants received the same conventional physical therapy, including transfer, balance, and ambulation training, during admission for 50 min per day during 2 weeks (10 sessions). Every session was preceded by 3 min procedure of cerebellar iTBS applyed over the contralesional cerebellum in the intervention group or by a similar sham iTBS in control group. The groups were formed randomly and the baseline characteristics showed no significant difference. The primary outcome measure was Fugl–Meyer Assessment–Lower Extremity scores. Secondary outcomes included walking performance and corticospinal excitability. Measures were performed before the intervention beginning (T0), after the first (T1) and the second (T2) weeks.Results: The Fugl–Meyer Assessment for lower extremity scores slightly improved with time in both groups with no significant difference between the groups and over the time. The walking performance significantly improved with time and between group. Two-way mixed measures ANOVA showed that there was significant interaction between time and group in comfortable walking time (F2,68 = 6.5242, P = 0.0080, η2partial = 0.276, ε = 0.641), between-group comparisons revealed significant differences at T1 (P = 0.0072) and T2 (P = 0.0133). The statistical analysis of maximum walking time showed that there was significant interaction between time and groups (F2,68 = 5.4354, P = 0.0115, η2partial = 0.198, ε = 0.734). Compared with T0, the differences of maximum walking time between the two groups at T1 (P = 0.0227) and T2 (P = 0.0127) were statistically significant. However, both the Timed up and go test and functional ambulation category scale did not yield significant differences between groups (P > 0.05).Conclusion: Our results revealed that applying iTBS over the contralesional cerebellum paired with physical therapy could improve walking performance in patients after stroke, implying that cerebellar iTBS intervention may be a noninvasive strategy to promote walking function in these patients. This study was registered at ChiCTR, number ChiCTR1900026450.

Physical activity scaled to preferred walking speed as a predictor of walking difficulty in older adults: a 2-year follow-up

Background The usual accelerometry-based measures of physical activity (PA) are dependent on physical performance. We investigated the associations between PA relative to walking performance and the prevalence and incidence of early and advanced walking difficulties compared to generally used measures of PA. Methods Perceived walking difficulty was evaluated in 994 community-dwelling participants at baseline (age 75, 80 or 85 years) and two years later over two kilometers (early difficulty) and 500 meters (advanced difficulty). We used a thigh-mounted accelerometer to assess moderate-to-vigorous PA, daily mean acceleration and relative PA as movement beyond the intensity of preferred walking speed in a 6-minute walking test (PArel). Self-reported PA was assessed using questionnaires. Results The prevalence and incidence were 36.2 % and 18.9 % for early, and 22.4 % and 14.9 % for advanced walking difficulty, respectively. PArel was lower in participants with prevalent (mean 42 (SD 45) vs. 69 (91) mins/week, p<0.001) but not incident early walking difficulty (53 (75) vs. 72 (96) mins/week, p=0.15) compared to those without difficulty. The associations between absolute measures of PA and incident walking difficulty were attenuated when adjusted for preferred walking speed. Conclusions The variation in habitual PA may not explain the differences in the development of new walking difficulty. Differences in physical performance explain a meaningful part of the association of PA with incident walking difficulty. Scaling of accelerometry to preferred walking speed demonstrated independence on physical performance and warrants future study as a promising indicator of PA in observational studies among older adults.

No benefit of vorapaxar on walking performance in patients with intermittent claudication

Background: The effect of pharmacologic agents in improving walking and quality of life measures in patients with intermittent claudication (IC) is variable. The objective of this study was to investigate the effect of the novel antithrombotic vorapaxar on symptom status in patients with IC. Methods: The study was a multicenter, randomized, placebo-controlled trial wherein patients with IC were treated with either vorapaxar or placebo in addition to a home exercise program for 6 months. Walking performance and quality of life were assessed by graded treadmill test (GTT) and 12-Item Short-Form Survey (SF-12), respectively, at baseline and at 6 months. A total of 102 subjects were randomized across 12 centers. Results: Of the subjects randomized, 66 completed all study assessments and comprised the dataset that was analyzed. After 6 months, there was no significant difference between the vorapaxar and placebo groups in walking performance, as reflected by the GTT, or in quality of life, as reflected by the SF-12. There were no severe bleeding events in either group. Conclusion: This study found no benefit of vorapaxar in patients with IC and reiterates the need for future drug therapy studies that expand the benefits of supervised exercise therapy in patients with IC. ClinicalTrials.gov Identifier: NCT02660866