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Effect of a load distribution system on mobility and performance during simulated and field hiking while under load.
Sessoms, PH, Gobrecht, M, Niederberger, BA, Sturdy, JT, Collins, JD, Dominguez, JA, Jaworski, RL, Kelly, KR
Ergonomics. 2020;(2):133-144
Abstract
This study was conducted to test a modular scalable vest-load distribution system (MSV-LDS) against the plate carrier system (PC) currently used by the United States Marine Corps. Ten Marines engaged in 1.6 km load carriage trials in seven experimental conditions in a laboratory study. Kinematic, kinetic, and spatiotemporal gait parameters, muscle activity (electromyography), heart rate, caloric expenditure, shooting reaction times, and subjective responses were recorded. There was lower mean trapezius recruitment for the PC compared with the MSV-LDS for all conditions, and muscle activity was similar to baseline for the MSV-LDS. Twenty-seven Marines carrying the highest load were evaluated in the field, which measured an increase in energy expenditure with MSV-LDS; however, back discomfort was reduced. The field evaluation showed significantly reduced estimated ground reaction force on flat-ground segments with the MSV-LDS, and the data suggest both systems were comparable with respect to mobility and energy cost. Practitioner summary: This study found that a novel load distribution system appears to redistribute load for improved comfort as well as reduce estimated ground reaction force when engaged in hiking activities. Further, hiking with a load distribution system enables more neutral walking posture. Implications of load differences in loads carried are examined. Abbreviations: AGRF anterior-posterior ground reaction forces; CAREN Computer Assisted Rehabilitation Environment; GRF: ground reaction forces; HR: heart rate; ML-GRF: mediolateral ground reaction forces; MOLLE Modular Lightweight Load-carrying Equipment; MSV-LDS: modular scalable vest-load distribution system; NHRC Naval Health Research Center; PC: plate carrier; PPE: personal protective equipment; RPE: rating of perceived exertion; SAPI small arms protective insert; sEMG: surface electromyography; USMC United States Marine Corps; VGRF Ground reaction forces in the vertical.
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Effect of Whole-Body Vibration Exercise on Power Profile and Bone Mineral Density in Postmenopausal Women With Osteoporosis: A Randomized Controlled Trial.
ElDeeb, AM, Abdel-Aziem, AA
Journal of manipulative and physiological therapeutics. 2020;(4):384-393
Abstract
OBJECTIVE The purpose of this study was to investigate the effect of whole-body vibration (WBV) on muscle work and bone mineral density (BMD) of the lumbar vertebrae and femur in postmenopausal women. METHODS Forty-three postmenopausal women with low BMD were randomly assigned to WBV and control groups. Both groups received calcium and vitamin D supplementations once daily, while the WBV group additionally received WBV exercise (twice/wk) for 24 successive weeks. Qualisys gait analysis system was used to measure hip power generation by hip extensors (H1S) and flexors (H3S), hip power absorption by hip flexors (H2S), knee power absorption by quadriceps during loading response (K1S) and preswing (K3S), knee power absorption by hamstring (K4S), knee power generation by quadriceps (K2S), ankle power absorption by dorsiflexors (A1S) and plantar flexors (A2S), and ankle power generation by plantar flexors (A3S). Also, dual-energy X-ray absorptiometry was used to measure BMD of the lumbar vertebrae and femur before and after the intervention. RESULTS There were significant increases (P < .05) in the hip muscle work (H1S, H2S, and H3S), knee muscle work (K1S, K2S, K3S, and K4S), ankle muscle work (A1S, A2S, and A3S) during gait, and BMD of the lumbar vertebrae and femur of the WBV group. However, there were no significant changes (P > .05) in the control group. The posttreatment values of the hip, knee, and ankle muscle work and BMD of the WBV group were significantly (P < .05) higher than the posttreatment values of the control group. CONCLUSION Whole-body vibration training improved the leg muscle work and lumbar and femoral BMD in postmenopausal women with low BMD.
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Association of Sex or Race With the Effect of Weight Loss on Physical Function: A Secondary Analysis of 8 Randomized Clinical Trials.
Beavers, KM, Neiberg, RH, Kritchevsky, SB, Nicklas, BJ, Kitzman, DW, Messier, SP, Rejeski, WJ, Ard, JD, Beavers, DP
JAMA network open. 2020;(8):e2014631
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Abstract
IMPORTANCE Consideration of differential treatment effects among subgroups in clinical trial research is a topic of increasing interest. This is an especially salient issue for weight loss trials. OBJECTIVE To determine whether stratification by sex and race is associated with meaningful differences in physical function response to weight loss among older adults. DESIGN, SETTING, AND PARTICIPANTS This pooled analysis used individual-level data from 8 completed randomized clinical trials of weight loss conducted at Wake Forest University or Wake Forest School of Medicine, Winston-Salem, North Carolina. Data were housed within the Wake Forest Older Americans Independence Center data repository and provided complete exposure, outcome, and covariate information. Data were collected from November 1996 to March 30, 2017, and analyzed from August 15, 2019, to June 10, 2020. EXPOSURES Treatment arms within each study were collapsed into caloric restriction (CR [n = 734]) and non-CR (n = 583) categories based on whether caloric restriction was specified in the original study protocol. MAIN OUTCOMES AND MEASURES Objectively measured 6-month change in weight, fast-paced gait speed (meters per second), and Short Physical Performance Battery (SPPB) score. RESULTS A total of 1317 adults (mean [SD] age, 67.7 [5.4] years; 920 [69.9%] female; 275 [20.9%] Black) with overweight or obesity (mean [SD] body mass index [calculated as weight in kilograms divided by height in meters squared], 33.9 [4.4]) were included at baseline. Six-month weight change achieved among those randomized to CR was -7.7% (95% CI, -8.3% to -7.2%), with no difference noted by sex; however, White individuals lost more weight than Black individuals assigned to CR (-9.0% [95% CI, -9.6% to -8.4%] vs -6.0% [95% CI, -6.9% to 5.2%]; P < .001), and all CR groups lost a significantly greater amount from baseline compared with non-CR groups (Black participants in CR vs non-CR groups, -5.3% [95% CI, -6.4% to -4.1%; P < .001]; White participants in CR vs non-CR groups, -7.2% [95% CI, -7.8% to -6.6%; P < .001]). Women experienced greater weight loss-associated improvement in SPPB score (CR group, 0.35 [95% CI, 0.18-0.52]; non-CR group, 0.08 [95% CI, -0.11 to 0.27]) compared with men (CR group, 0.23 [95% CI, 0.00-0.46]; non-CR group, 0.34 [95% CI, 0.09-0.58]; P = .03). Black participants experienced greater weight loss-associated improvement in gait speed (CR group, 0.08 [95% CI, 0.05-0.10] m/s; non-CR group, 0.02 [95% CI, -0.01 to 0.05] m/s) compared with White participants (CR group, 0.07 [95% CI, 0.06-0.09] m/s; non-CR group, 0.06 [95% CI, 0.04-0.08] m/s; P = .02). CONCLUSIONS AND RELEVANCE The association of weight loss on physical function in older adults appears to differ by sex and race. These findings affirm the need to consider biological variables in clinical trial design.
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Interaction Between Vitamin D and Interleukin 6 on Slow Gait Speed: 6-Year Follow-up Data of Older Adults From InCHIANTI.
Kositsawat, J, Kuo, CL, Barry, LC, Melzer, D, Bandinelli, S, Ferrucci, L, Wu, R, Kuchel, GA
The journals of gerontology. Series A, Biological sciences and medical sciences. 2020;(6):1161-1166
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Abstract
BACKGROUND Whereas the independent effects of biomarkers, including 25-hydroxy vitamin D (25(OH)D), insulin-like growth factor 1, C-reactive protein, and interleukin 6 (IL-6), on gait speed in older adults have been evaluated, their joint effects on gait speed are not well understood. METHODS Study subjects aged at least 65 at baseline (N = 970) were enrolled in the population-based Invecchiare in Chianti (InCHIANTI) study from 1998 to 2000 and were followed up at 3 and 6 years. All above biomarkers and gait speed data were measured at each of the three time points. Using a generalized estimating equation approach, we determined if slow gait speed (<0.8 m/s) was associated with the biomarkers. Further investigation was conducted for interactions between high IL-6 (≥.87 pg/mL) and other biomarkers focusing on low 25(OH)D (<20 ng/mL). RESULTS After controlling for other biomarkers and potential confounders, IL-6 emerged as the only biomarker independently associated with gait speed. The association between high IL-6 and slow gait speed was enhanced by low 25(OH)D, with significant interaction between high IL-6 and low 25(OH)D (p = .038). The odds ratio of slow gait speed for low 25(OH)D and high IL-6 was 1.63 (95% confidence interval [CI]: 1.15, 2.32) compared with the reference groups with both biomarker levels at the other ends. CONCLUSION The association of low vitamin D with slow gait speed statistically interacts with high IL-6. Coexisting vitamin D insufficiency and inflammation may provide a better biomarker for identifying those at risk of developing impairments in gait speed than either factor alone.
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Corticomuscular control of walking in older people and people with Parkinson's disease.
Roeder, L, Boonstra, TW, Kerr, GK
Scientific reports. 2020;(1):2980
Abstract
Changes in human gait resulting from ageing or neurodegenerative diseases are multifactorial. Here we assess the effects of age and Parkinson's disease (PD) on corticospinal activity recorded during treadmill and overground walking. Electroencephalography (EEG) from 10 electrodes and electromyography (EMG) from bilateral tibialis anterior muscles were acquired from 22 healthy young, 24 healthy older and 20 adults with PD. Event-related power, corticomuscular coherence (CMC) and inter-trial coherence were assessed for EEG from bilateral sensorimotor cortices and EMG during the double-support phase of the gait cycle. CMC and EMG power at low beta frequencies (13-21 Hz) was significantly decreased in older and PD participants compared to young people, but there was no difference between older and PD groups. Older and PD participants spent shorter time in the swing phase than young individuals. These findings indicate age-related changes in the temporal coordination of gait. The decrease in low-beta CMC suggests reduced cortical input to spinal motor neurons in older people during the double-support phase. We also observed multiple changes in electrophysiological measures at low-gamma frequencies during treadmill compared to overground walking, indicating task-dependent differences in corticospinal locomotor control. These findings may be affected by artefacts and should be interpreted with caution.
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Improving Trip- and Slip-Resisting Skills in Older People: Perturbation Dose Matters.
Karamanidis, K, Epro, G, McCrum, C, König, M
Exercise and sport sciences reviews. 2020;(1):40-47
Abstract
Aging negatively affects balance recovery responses after trips and slips. We hypothesize that older people can benefit from brief treadmill-based trip and slip perturbation exposure despite reduced muscular capacities, but with neuropathology, their responsiveness to these perturbations will be decreased. Thus, to facilitate long-term benefits and their generalizability to everyday life, one needs to consider the individual threshold for perturbation dose.
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Computer interactions during walking workstation use moderately affects spatial-temporal gait characteristics.
Eggleston, JD, Chavez, EA, Harry, JR, Dufek, JS
Gait & posture. 2019;:200-204
Abstract
BACKGROUND Due to increased sedentary workstyles, active workstations have shown the ability to increase activity while only moderately affecting work ability. However, previous examinations have not examine fine motor mousing tasks on tripping descriptors. RESEARCH QUESTION What affect do mousing tasks of varying target size have on tripping descriptors during walking workstation use? METHODS Three-dimensional kinematic data were collected while participants used a walking workstation completing one baseline and three mousing conditions of varying target sizes. RESULTS Target size main effects (p < 0.001) detected decreased stride length in all experimental conditions, which were supported by moderate effect sizes, and decreased stance width and time in double limb support (p < 0.001 for both comparisons). Stance width differences resulted in large effect sizes between baseline and all conditions, while only moderate effect sizes were observed between time in double limb support in baseline compared to all conditions. No changes in knee flexion range of motion were observed in response to target size (p = 0.278). SIGNIFICANCE These results indicate that walking workstation users shorten their stride length and decrease their base of support while completing mousing tasks. The placement of the upper extremities on the workstation desk likely acted as the primary mechanism to increase stability. It is concluded that performing mousing tasks of varying target size using a walking workstation does not pose greater risk for adverse gait events.
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Progressive changes in walking kinematics throughout pregnancy-A follow up study.
Forczek, W, Ivanenko, Y, Curyło, M, Frączek, B, Masłoń, A, Salamaga, M, Suder, A
Gait & posture. 2019;:518-524
Abstract
BACKGROUND Progressive weight gain and changes in its distribution following pregnancy may be challenging for the gravidas' ability to move in a stable way. RESEARCH QUESTION How is gait kinematics changing throughout pregnancy and to what extend is it affected by physical activity level and energy balance? METHODS 30 women were enrolled. Three experimental sessions were arranged according to the same protocol in the first, second and third trimesters of pregnancy. Walking kinematics at a self-selected speed was registered. The total physical activity (TPA) was assessed from the subjects' questionnaires. Energy balance ('positive', 'balanced' or 'negative') was estimated as the difference between dietary energy intake and energy expenditure during 7 days. RESULTS No significant differences were found in the spatiotemporal variables between experimental sessions. However, the gait analysis revealed significant increments in the single support and base of support (BoS) measures. Generally, the sagittal plane mobility of the lower limb joints did not differ, however, the pelvic tilt increased in late pregnancy. The hip and pelvis angles were significantly different over the gait cycle throughout gestation. The 'balanced' energy was dominant in the first trimester although the relative number of participants with negative balance increased over pregnancy. Overall, gait parameters were independent of the energy balance. However, significant correlation was found between gait parameters, such as BoS, velocity, stride length, and TPA in the advanced pregnancy. SIGNIFICANCE The longitudinal assessment of walking kinematics demonstrates few changes adopted to accommodate for pregnancy. The enlargement of BoS is considered as a strategy to provide safety and stability. The increased pelvic tilt is likely to compensate for changes in the body mass distribution. The physical activity correlates with the BoS measures and stride length and thus may be important for enhancing gait stability.
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Combining a high DHA multi-nutrient supplement with aerobic exercise: Protocol for a randomised controlled study assessing mobility and cognitive function in older women.
Fairbairn, P, Tsofliou, F, Johnson, A, Dyall, SC
Prostaglandins, leukotrienes, and essential fatty acids. 2019;:21-30
Abstract
There is a complex interplay between cognition and gait in older people, with declines in gait speed coexisting with, or preceding cognitive decline. Omega-3 fatty acids, B vitamins, vitamin E, phosphatidylserine, and Ginkgo Biloba show promise in preserving mobility and cognitive function in older adults. Exercise benefits mobility and there is evidence suggesting positive interactions between exercise and omega-3 fatty acids on physical and cognitive function in older adults. Non-frail or pre-frail females aged ≥60 years are included in a randomized placebo controlled study. Intervention groups are: high DHA multi-nutrient supplement and exercise, placebo supplement and exercise, high DHA multi-nutrient supplement, and placebo supplement. Dietary supplementation is 24 weeks. The exercise intervention, two cycle ergometer classes per week, is for the final 12 weeks. The primary outcome is habitual walking speed, secondary outcomes include gait variables under single and dual task, five times sit to stand, verbal and spatial memory, executive function, interference control and health related quality of life. Blood fatty acids, serum homocysteine, dietary intake, physical activity, and verbal intelligence are measured to assess compliance and control for confounding factors. The study is registered at www.clinicaltrials.gov (NCT03228550).
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Predicting responsiveness to fampridine in gait-impaired patients with multiple sclerosis.
Filli, L, Werner, J, Beyer, G, Reuter, K, Petersen, JA, Weller, M, Zörner, B, Linnebank, M
European journal of neurology. 2019;(2):281-289
Abstract
BACKGROUND AND PURPOSE Fampridine leads to significant improvements in walking in many people with multiple sclerosis (PwMS). However, a relevant proportion of PwMS does not respond to fampridine and predictors of initial drug responsiveness are unknown. METHODS Drug response to prolonged-release (PR)-fampridine was assessed in 55 PwMS using the timed 25-foot walk (T25FW), 6-min walk test (6MWT) and 12-item multiple sclerosis walking scale as outcome parameters. Patients were treated with PR-fampridine and placebo for 6 weeks each in a randomized, double-blind, placebo-controlled trial with crossover design (NCT01576354). Possible predictors of drug responsiveness were investigated by multiple correlation analysis and binary logistic regression models. An additional longitudinal analysis followed the drug responses of 32 patients treated with PR-fampridine over 3 years to identify potential predictors of long-term drug responsiveness. RESULTS Severity of walking disability was positively correlated with enhanced responses to PR-fampridine. The strongest single predictor of drug responsiveness was poor 6MWT performance at baseline, which was positively correlated with enhanced drug response in the 6MWT (R = -0.541; P < 0.001). A multivariable logistic regression model including 6MWT and T25FW baseline performances predicted PR-fampridine responder status with an accuracy of 85.5% (specificity, 90.0%; sensitivity, 73.3%), with a threshold of 211 m in the 6MWT best separating responders from non-responders. Enhanced drug responsiveness after 3 years correlated with decline in walking endurance during this period (R = -0.634; P = 0.001). CONCLUSIONS Initial walking impairment is a good predictor of therapeutic responsiveness to PR-fampridine. Valid predictors of patients' responsiveness to PR-fampridine are essential for patient stratification and optimization of multiple slcerosis treatment.