An Equation With Clinical Applicability and Adequate Validity to Predict the Maximum Oxygen Consumption of Individuals Post-stroke

ObjectiveTo develop an equation with clinical applicability and adequate validity to predict the maximum oxygen consumption (V̇o_2max) of individuals post-stroke.DesignA cross-sectional study.SettingA university laboratory.ParticipantsIndividuals post-stroke in the chronic phase (at least 6 months post-stroke). Step-1 (equation development): n=50, aged 55±12 years; Step-2 (validity investigation): n=20, aged 58±8 years (N=50 [step 1], N=20 [step 2]).InterventionsNot applicable.Main Outcome Measure(s)Step-1 (equation development): multiple linear regression analysis was performed. Dependent variable: V̇o_2max (mL/kg^/min) in the cardiopulmonary exercise test. Independent variables: age (years), sex (1-women, 2-men), body mass index (BMI) (kg/m²), and distance (meters) in the Six-Minute Walk Test (6MWT) (6MWT-Equation) or in the Incremental Shuttle Walk Test (ISWT) (ISWT-Equation). Step-2 (validity investigation): agreement between the V̇o_2max measured and predicted was evaluated with the intraclass correlation coefficient (ICC) with 95% confidence interval (CI) and the Bland-Altman method (α=5%).ResultsIn step-1 (equation development), the 4 independent variables for each equation were retained (6MWT-Equation: R²=0.68, P<.001; ISWT-Equation: R²=0.58, P<.001). In step-2 (validity investigation), the 6MWT-Equation showed an ICC of 0.73 (95% CI=0.30, 0.89; P=.004) and a mean bias of 0.003 mL/kg/min; and the ISWT-Equation showed an imprecise ICC of 0.55 (95% CI=-0.12, 0.82; P=.045) and a mean bias of 0.971 mL/kg/min. 6MWT-Equation (V̇o_2max=22.239+0.02 × distance in the 6MWT+4.039 × sex-0.157 × age-0.265 × BMI) showed adequate validity.ConclusionsAn equation with clinical applicability and adequate validity in the investigated sample was developed to predict the V̇o_2max of individuals post-stroke in the chronic phase (6MWT-Equation). Future studies with larger sample should investigate its external validity.     

Control of Linear Head and Trunk Acceleration During Gait After Unilateral Vestibular Deficits

ObjectiveTo use clinically available inertial measurement units to quantify the control of linear accelerations at the head and trunk during gait in different sensory conditions in individuals with unilateral vestibular loss.DesignObservational study.SettingOutpatient research laboratory.ParticipantsIndividuals (n=13; mean age, 47.6±13.7y; 69% women) 6 weeks after vestibular schwannoma resection surgery and vestibular healthy participants (n=16; mean age, 29.7±5.9y; 56% women).InterventionNot applicable.Main Outcome MeasuresWalking speed normalized, root mean square values of cranial-caudal, medial-lateral, and anterior-posterior directed linear accelerations at the head and the trunk while walking in 2 visual sensory conditions (eyes open and eyes closed).ResultsLinear mixed models for each root mean square value were fit on the effects of group, condition, and group by condition. The group by condition effect was used to examine the primary hypothesis that individuals with vestibular loss would experience greater change in triplanar root mean square values at the head and trunk from the eyes open to eyes closed condition compared with the vestibular healthy group. The group by condition effect was found to be significant at the head in the cranial-caudal (β=0.39; P=.002), medial-lateral (β=0.41; P<.001), and anterior-posterior (β=0.43; P<.001) directions. The group by condition effect was also significant in the cranial-caudal (β=0.39; P=.002), medial-lateral (β=0.39; P<.001), and anterior-posterior (β=0.23; P=.002) directions at the trunk.ConclusionsParticipants who underwent vestibular schwannoma resection were more impaired in their ability to control accelerations at the head and trunk without visual sensory information than vestibular healthy participants. These impairments were detectable using clinically available inertial measurement units.     

Characterizing Physical Activity and Sedentary Behavior in Adults With Persistent Postconcussive Symptoms After Mild Traumatic Brain Injury

ObjectiveTo evaluate physical activity (PA) and sedentary behavior and their associations with symptom and quality of life outcomes in adults with persistent postconcussive symptoms (PPCS) after mild traumatic brain injury (mTBI).DesignCross-sectional cohort study.SettingOutpatient brain injury clinic.ParticipantsConsecutive sample of adults (N=180) with a diagnosis of mTBI and PPCS.InterventionsNot applicable.Main Outcome MeasuresPA and sedentary behavior were assessed using the Godin Leisure-Time Exercise Questionnaire and Rapid Assessment Disuse Index, respectively. Participants were dichotomized according to whether they completed 150 minutes of moderate-to-vigorous PA per week, based on Canadian guidelines. Postinjury moderate-to-vigorous PA was also analyzed as a continuous variable.ResultsPrior to injury, 85% of participants reported meeting PA guidelines, compared with 28% postinjury. Individuals meeting PA guidelines postinjury reported higher quality of life (η²_p=0.130; P<.001) and lower scores on measures of functional impact of headache (η²_p=0.065; P=.009), fatigue (η²_p=0.080; P=.004), depression (η²_p=0.085; P=.001), and anxiety (η²_p=0.046; P=.031), compared with those not meeting guidelines. Sedentary behavior postinjury was negatively correlated with quality of life (r_s[127]=–0.252; P=.004) and positively correlated with symptom burden (r_s[167]=0.227; P=.003), fatigue (r_s[127]=0.288; P=.001), depression (r_s[174]=0.319; P<.001), and anxiety (r_s[127]=0.180; P=.042).ConclusionsPA was significantly decreased in individuals with PPCS compared to preinjury levels. Meeting PA guidelines postinjury was associated with better clinical outcomes, suggesting that returning individuals to PA should be considered in the treatment of this patient population.     

Characterization of the Obese Phenotype of Heart Failure With Preserved Ejection Fraction: A RELAX Trial Ancillary Study

ObjectiveTo characterize the obese heart failure with preserved ejection fraction (HFpEF) phenotype in a multicenter cohort.Patients and MethodsThis was a secondary analysis of the randomized clinical trial RELAX (Phosphodiesterase-5 Inhibition to Improve Clinical Status and Exercise Capacity in Heart Failure with Preserved Ejection Fraction) performed between October 1, 2008, and February 1, 2012. Patients with HFpEF were classified by body mass index (BMI) as obese (BMI≥35 kg/m²) and nonobese (BMI<30 kg/m²) for comparison.ResultsObese patients with HFpEF (n=81) were younger (median age, 64 [interquartile range (IQR), 67-79] years vs 73 [IQR, 56-70] years; P<.001) but had greater peripheral edema (31% [25] vs 9% [6]; P<.001), more orthopnea (76% [56] vs 53% [35]; P=.005), worse New York Heart Association class (P=.006), and more impaired quality of life (P<.001) as compared with nonobese patients with HFpEF (n=70). Despite more severe signs and symptoms, obese patients with HFpEF had lower N-terminal pro B-type natriuretic peptide level (median, 481 [IQR, 176-1183] pg/mL vs 825 [IQR, 380-1679] pg/mL [to convert to pmol/L, multiply by 0.118]; P=.007) and lower left atrial volume index (median, 38 [IQR, 31-47] mL/m² vs 54 [IQR, 41-63] mL/m²; P<.001). Serum C-reactive protein (median, 5.0 [IQR, 2.4-9.9] mg/dL vs 2.7 [IQR, 1.6-5.4] mg/dL [to convert to mg/L, multiply by 10^?3]; P<.001) and uric acid (median, 7.8 [IQR, 6.1-8.7] mg/dL vs 6.8 [IQR, 5.5-8.3] mg/dL; P=.03) levels were higher in obese HFpEF, indicating greater systemic inflammation, than in nonobese HFpEF. Peak oxygen consumption was impaired in obese HFpEF (median, 11.1 [IQR, 9.6-14.4] mL/kg per minute vs 13.1 [IQR, 11.3-14.7] mL/kg per minute; P=.008), as was submaximal exercise capacity (6-minute walk distance, 272 [IQR, 200-332] m vs 355 [IQR, 290-415] m; P<.0001).ConclusionObese HFpEF is associated with decreased quality of life, worse symptoms of heart failure, greater systemic inflammation, worse exercise capacity, and higher metabolic cost of exertion as compared with nonobese HFpEF. Further study is required to understand the pathophysiology and potential distinct treatments for patients with the obese phenotype of HFpEF.Trial Registrationclinicaltrials.gov Identifier: NCT00763867     

Protective Effect of Exercise in Pregnant Women Including Those Who Exceed Weight Gain Recommendations: A Randomized Controlled Trial

ObjectiveTo investigate the effect of supervised moderate to vigorous exercise on gestational weight gain, its related risks (gestational diabetes [GD]), macrosomia, and type of delivery), and the preventive effects on women who exceed the weight gain recommendations.Patients and MethodsWe conducted a single-center, 2-armed, randomized controlled trial between October 1, 2009, and June 30, 2011, in which 678 women were assessed and 345 were randomized by a central computer system to an intervention group (N=115) or a standard care group (N=230). The intervention exercise program consisted of 70 to 78 sessions (24 weeks, 3 times per week, 60-65 minutes per session, moderate to vigorous intensity). The standard care group received usual care. Excessive gestational weight (EGW) gain was calculated on the basis of the 2009 Institute of Medicine (IOM) recommendations.ResultsOf the 345 women randomized for treatment, 44 were lost to follow-up, leaving 301 women for analysis (intervention, 100; standard care, 201). Fewer women in the intervention group exceeded IOM recommendations (22 [22.0%] vs 69 [34.3%]; P=.03), including overweight and obese women (15 of 35 [42.9%] vs 40 of 50 [80.0%]; P=.001). Analysis of women exceeding weight recommendations revealed that the 3 main related risks were directly related to EGW gain in the standard care group (GD, P=.003; macrosomia, P<.001; type of delivery, P<.001) but not in the intervention group (GD, P>.99; macrosomia, 0%; type of delivery, P=.46).ConclusionSupervised moderate to vigorous exercise performed throughout gestation was effective in the prevention of EGW gain even for women with a pregestational body mass index greater than 25 kg/m². It also prevented its related risks (GD, macrosomia, and type of delivery) including for women exceeding the IOM recommendations, so we suggest that being active outweighs the effect of possible weight gain.Trial RegistrationClinicalTrials.gov Identifier: NCT01477372     

Effect of fluid collections on long-term outcome after lower limb amputation

Singh R, Venkateshwara G. Effect of fluid collections on long-term outcome after lower limb amputation.ObjectiveTo ascertain the long-term outcome for individuals found to have fluid collections in residual limbs after amputation.DesignProspective cohort study.SettingOutpatient follow-up at a prosthetic rehabilitation unit.ParticipantsSuccessive lower limb amputations (N=105) scanned for fluid collections after operation and followed up after 3 years.InterventionsNot applicable.Main Outcome MeasuresSurvival; secondary outcomes of prosthetic limb use, hours of prosthetic limb-wearing, anxiety and depression levels.ResultsAfter 3 years, 70 individuals were alive, of whom 21 (30%) had fluid collections originally. There was no significant difference at follow-up between the group that had fluid collections in their residual limbs after surgery and the group that did not in terms of survival (χ²₁=.21, P=.64), numbers wearing prosthetic limb (χ²₁=.102, P=.75), hours of limb wearing (t₃₇=.35, P=.72), anxiety (χ²₁=.77, P=.78), and depression (χ²₁=1.98, P=.16). A multivariable logistic regression confirmed that presence of fluid collection was not associated with survival.ConclusionsFluid collections in residual limbs after amputation are common, but patients can be reassured that their long-term outcomes are not affected.     

Internet-Delivered Lifestyle Physical Activity Intervention Improves Body Composition in Multiple Sclerosis: Preliminary Evidence From a Randomized Controlled Trial

Objective

To examine the efficacy of a physical activity behavioral intervention for improving outcomes of body composition in persons with multiple sclerosis (MS).

Design

Secondary analysis of data from a randomized controlled trial.

Setting

University research laboratory.

Participants

Ambulatory persons with MS (N=82).

Intervention

A 6-month, internet-delivered physical activity behavioral intervention designed to increase lifestyle physical activity, primarily walking. The behavioral intervention was based on principles of social cognitive theory.

Main Outcome Measures

Whole-body bone mineral content (BMC), bone mineral density (BMD), and soft tissue composition, using dual-energy x-ray absorptiometry.

Results

There were no significant differences between conditions posttrial on body composition outcomes using the adjusted critical value (P<.008). There was a significant effect of the intervention on whole-body BMC (P=.04, ω²<.001) and BMD (P=.01, ω²=.003) using the unadjusted critical value (P<.05). The effect of the intervention on percent body fat (P=.09, ω²=.001) and whole-body fat mass (P=.05, ω²=.003) approached significance using unadjusted criteria. There was not a significant effect on whole-body lean soft tissue (P=.28, ω²<.001) or body mass index (P=.86, ω²<.001).

Conclusions

Our results provide preliminary evidence that an internet-delivered lifestyle physical activity intervention might improve bone health and body composition in MS. Such findings are important considering that physical activity is a modifiable behavior with the potential to confer long-term benefits for the prevention and management of fracture risk and comorbidities among those with MS.     

Effects of Air Stacking on Dyspnea and Lung Function in Neuromuscular Diseases

ObjectiveTo investigate whether the decrease in dyspnea in neuromuscular diseases after air stacking (AS) occurs mostly in patients with decreased inspiratory muscle force and ensuing chest wall restriction or heterogeneous ventilation across the lungs.DesignInterventional, before-after study.SettingA neurorehabilitation inpatient and outpatient center.ParticipantsFifteen consecutive adult patients affected by neuromuscular diseases (N=15).InterventionsAS treatment.Main Outcome MeasuresPatients had vital capacity (VC) and sniff nasal inspiratory pressure (SNIP) measured. We measured Borg score, oxygen saturation, and ventilation heterogeneity across the lung as estimated from the difference between respiratory resistance at 5 and 19 Hz (R_5-19) with the forced oscillation technique before and 5, 30, 60, and 120 minutes after applying AS.ResultsBefore AS, Borg score was significantly related to R_5-19 (r² 0.46, P<.05) but not to VC % predicted, SNIP % predicted, and time since symptom onset. After AS, average Borg score gradually decreased (P=.005), whereas inspiratory flow resistance at 5 Hz, R_5-19, and inspiratory reactance at 5 Hz tended to improve, despite not reaching statistical significance. The decrease in dyspnea at 60 and 120 minutes after AS significantly correlated with baseline R_5-19 (r² 0.49, P<.01 and r² 0.29, P<.05, respectively), but not with VC % predicted, SNIP % predicted, time since symptom onset, and clinical severity score for patients affected by amyotrophic lateral sclerosis.ConclusionsThese findings suggest that dyspnea in neuromuscular diseases is related to heterogeneous ventilation rather than inspiratory muscle force and/or lung volumes decrease. Restoring ventilation distribution across the lungs with AS appears to improve dyspnea.     

Knee Flexor Strength and Endurance Profiles After Ipsilateral Hamstring Tendons Anterior Cruciate Ligament Reconstruction

Objectives

To profile knee flexor strength and endurance responses to ipsilateral hamstring tendon autograft anterior cruciate ligament reconstruction in patients, and to describe knee flexor strength and endurance as predictors of subjective outcomes. The hypothesis was that the involved leg would demonstrate deficits compared with uninvolved and matched legs.

Design

Retrospective cohort.

Setting

Controlled laboratory.

Participants

Women (n=15; mean age, 20.47±1.96y; height, 1.69±.08m; weight, 68.51±12.64kg), who were a mean ± SD of 25.93±11.25 months postsurgery, were matched to 15 sex-matched controls (mean age, 20.93±1.22y; height, 1.65±.06m; weight, 66.52±10.69kg).

Interventions

Not applicable.

Main Outcome Measures

Concentric peak flexor moment over the entire isokinetic joint range of motion, peak flexor moment at 105° of joint flexion, and knee flexor total work, normalized to body mass, and subjective questionnaire scores for the involved leg.

Results

Significantly lesser peak flexor moment over the entire isokinetic joint range of motion (P=.034) and total work (P=.048) existed for the involved leg (.959±.186Nm/kg; 21.933±5.881J/kg) compared with the matched leg (1.108±.134Nm/kg; 27.431±6.499J/kg). Significantly lesser peak flexor moment at 105° of joint flexion (P=.002) existed between the involved (.221±.116Nm/kg) and uninvolved (.40±.234Nm/kg) and matched (.475±.183Nm/kg) legs. Significantly greater strength deficits (P≤.001) existed at peak flexor moment at 105° of joint flexion compared with peak flexor moment over the entire isokinetic joint range of motion for side (53.83%±38.8%; 9.87%±10.77%) and group (77.61%±44.14%; 18.09%±11.73%) differences. Peak flexor moment at 105° of joint flexion was a significant predictor of subjective pain (P=.007), symptoms (P=.006), function (P=.011), and sports (P=.022) outcomes.

Conclusions

Knee flexor strength and endurance deficits suggest susceptibility to reinjury, and strength in a deep joint angle predicts subjective outcomes.     

Effect of Exoskeletal-Assisted Walking on Soft Tissue Body Composition in Persons With Spinal Cord Injury

ObjectiveTo determine the effect of overground walking using a powered exoskeleton on soft tissue body composition in persons with spinal cord injury (SCI).DesignA prospective, single group observational pilot study.SettingMedical center.ParticipantsPersons (N=8) with chronic (>6mo) SCI between 18 and 65 years old who weighed less than 100 kg.InterventionsOverground ambulation training using a powered exoskeleton (ReWalk) for 40 sessions, with each session lasting up to 2 hours, with participants training 3 times per week.Main Outcome Measure(s)Dual-energy x-ray absorptiometry (DXA) was used to measure lean mass (LM) and fat mass (FM) from the whole body, arms, legs and trunk. DXA was also used to assess visceral adipose tissue (VAT). Walking performance was measured by 6-minute walk test.ResultsParticipants significantly lost total body FM (?1.8±1.2kg, P=.004) with the loss of adiposity distributed over several regional sites. Six of the 8 participants lost VAT, with the average loss in VAT trending toward significance (?0.141kg, P=.06). LM for the group was not significantly changed.ConclusionsSustained and weekly use of powered exoskeletons in persons with SCI has the potential to reduce FM with inferred improvements in health.     

Trunk Muscle Composition 2 Months After Hip Fracture: Findings From the Baltimore Hip Studies

ObjectiveTo determine if hip fracture patients would have smaller cross-sectional area (CSA) and lower radiological attenuation (suggesting greater fat infiltration) in all trunk muscles as compared to older adults without hip fractures.DesignCross-sectional analysis of computed tomography (CT) scans.SettingClinical imaging facility.ParticipantsForty-one white participants (19 men, 22 women) from the Baltimore Hip Studies seventh cohort at 2 months postfracture were compared to 693 white participants (424 men, 269 women) from the Health, Aging and Body Composition (Health ABC) study at the year 6 visit (N=734).InterventionNot applicable.Main Outcome MeasuresTrunk muscle CSA and attenuation values were obtained from a single 10-mm, axial CT scan completed at the L4-L5 disc space in each participant.ResultsThe hip fracture cohort had significantly smaller CSA for all trunk muscles (range: 12.1%-38% smaller) compared to the Health ABC cohort (P<.01), with the exception of the rectus abdominus muscle in men (P=.12). But, hip fracture patients, particularly female patients, had higher attenuation levels (lower intramuscular fat) in all trunk muscles (P<.0001).ConclusionsFindings are consistent with atrophy of the trunk muscles in the hip fracture population without a high level of intramuscular fat. Future work should evaluate the role of trunk muscle composition in the functional recovery of older adults after hip fracture.     

Effect of loss of regional fat assessed by DXA on insulin resistance and dyslipidaemia in obese men

Abstract

Objective. To investigate the impact of reduction in total fat mass (FM) and regional FMs on indices of insulin resistance and dyslipidaemia in obese men (BMI > 30 kg/m²) after a 1-year weight loss (WL), and secondly, to examine the potential predictive effect of baseline insulin resistance on reduction in total and regional FMs. Material and methods. In nine men with WL > 4 kg, body composition by DXA (dual X-ray absorptiometry) and indices of insulin resistance were assessed: fasting insulin, C-Peptide and HOMA-IR. Insulin sensitivity (QUICKI) and serum lipids were also assessed. Results. Mean WL was 10.8%; Δ trunk and Δ leg FM were reduced by 30.1% and 21.3%, respectively, increasing leg/trunk FM ratio by 13.2%. Improvement in HOMA-IR was 63.1%, insulin 59.1%, and in QUICKI 17.4%. Loss of total FM, trunk FM, and increase in leg/trunk FM ratio were correlated with improvement in HOMA-IR (p < 0.001–0.05). Linear regression analysis of ln-transformed improvements in HOMA-IR was non-significantly related with losses of trunk FM and increases in leg/trunk FM ratio (p = 0.06). Multivariate analysis suggested improvements in fasting insulin and C-Peptide could be explained by leg/trunk FM ratio (R² = 0.60, p = 0.013, R² = 0.37, p = 0.012, respectively) and in HOMA-IR by trunk FM (R² = 0.42, p = 0.06). The loss of FM and change in FM distribution had no effect on serum lipids. Conclusion. Both loss of trunk FM and increase in leg/trunk FM ratio assessed by DXA contribute to the improvement in insulin resistance.     

Accurate prediction of cardiorespiratory fitness using cycle ergometry in minimally disabled persons with relapsing-remitting multiple sclerosis

Motl RW, Fernhall B. Accurate prediction of cardiorespiratory fitness using cycle ergometry in minimally disabled persons with relapsing-remitting multiple sclerosis.ObjectiveTo examine the accuracy of predicting peak oxygen consumption (Vo_2peak) primarily from peak work rate (WR_peak) recorded during a maximal, incremental exercise test on a cycle ergometer among persons with relapsing-remitting multiple sclerosis (RRMS) who had minimal disability.DesignCross-sectional study.SettingClinical research laboratory.ParticipantsWomen with RRMS (n=32) and sex-, age-, height-, and weight-matched healthy controls (n=16) completed an incremental exercise test on a cycle ergometer to volitional termination.InterventionNot applicable.Main Outcome MeasuresMeasured and predicted Vo_2peak and WR_peak.ResultsThere were strong, statistically significant associations between measured and predicted Vo_2peak in the overall sample (R²=.89, standard error of the estimate=127.4mL/min) and subsamples with (R²=.89, standard error of the estimate=131.3mL/min) and without (R²=.85, standard error of the estimate=126.8mL/min) multiple sclerosis (MS) based on the linear regression analyses. Based on the 95% confidence limits for worst-case errors, the equation predicted Vo_2peak within 10% of its true value in 95 of every 100 subjects with MS.ConclusionsPeak Vo₂ can be accurately predicted in persons with RRMS who have minimal disability as it is in controls by using established equations and WR_peak recorded from a maximal, incremental exercise test on a cycle ergometer.     

Relationships Between Wheelchair Services Received and Wheelchair User Outcomes in Less-Resourced Settings: A Cross-Sectional Survey in Kenya and the Philippines

ObjectiveTo explore the relationships between wheelchair services received during wheelchair provision and positive outcomes for users of wheelchairs.DesignSecondary analysis of cross-sectional data.SettingUrban and periurban communities in Kenya and the Philippines.ParticipantsAdult basic manual wheelchair users (N=852), about half of whom reported having received some wheelchair services with the provision of their current wheelchairs.InterventionsNot applicable.Main Outcome MeasuresParticipants completed a survey that included questions related to demographic, clinical, and wheelchair characteristics. The survey also included questions about the past receipt of 13 wheelchair services and 4 positive outcomes for users of wheelchairs. The relationships between individual services received and positive outcomes were assessed using logistic regression analyses. In addition to assessing individual services and outcomes, we analyzed a composite service score (the total number of services received) and a composite outcome score (≥3 positive outcomes).ResultsThe top 3 individual services from the perspective of relationships with the composite outcome score were “provider did training” (P=.0009), “provider assessed wheelchair fit while user propelled the wheelchair” (P=.002), and “peer group training received” (P=.033). The composite service score was significantly related to “daily wheelchair use” (P<.0001), “outdoor unassisted wheelchair use” (P<.0001), “high performance of activities of daily living” (P=.046) and the composite outcome score (P=.005), but not to the “absence of serious falls” (P=.73).ConclusionsThe receipt of wheelchair services is associated with positive outcomes for users of wheelchairs, but such relationships do not exist for all services and outcomes. These findings are highly relevant to ongoing efforts to optimize wheelchair service delivery.     

Relationships between mediolateral trunk-pelvic motion,hip strength,and knee joint moments during gait among persons with lower limb amputation

BackgroundRepeated exposures to larger lateral trunk-pelvic motion and features of knee joint loading likely influence the onset of low back pain and knee osteoarthritis among persons with lower-limb amputation. Decreased hip abductor strength can also influence frontal plane trunk-pelvic motion and knee moments; however, it is unclear how these are inter-related post-amputation.MethodsTwenty-four participants with unilateral lower-limb amputation (14 transtibial; 10 transfemoral) and eight uninjured controls walked at 1.3 m/s while full-body biomechanical data were captured. Multiple linear regression and Cohen's f² predicted (P < 0.05) the influences of mediolateral trunk and pelvic ranges of motion and angular accelerations, and bilateral isometric hip abductor strength on peak (intact) knee adduction moment and loading rate.FindingsThere were no group differences in hip strength, peak knee adduction moment or pelvis acceleration (p > 0.06). The combination of hip strength, and mediolateral trunk and pelvic motion did not predict (F_(5,29) = 2.53, p = 0.06, adjusted R² = 0.27, f² = 0.08) peak knee adduction moment. However, the combination of hip strength and trunk and pelvis acceleration predicted knee adduction moment loading rate (F_(7,29) = 3.59, p = 0.008, adjusted R² = 0.45, f² = 0.25), with peak trunk acceleration (β = 0.72, p = 0.008) and intact hip strength (β = 0.78, p = 0.008) significantly contributing to the model.InterpretationThese data suggest increased hip abductor strength counteracts increased lateral trunk acceleration, concomitantly influencing the rate at which the ground reaction force vector loads the intact knee joint. Persons with lower-limb amputation perhaps compensate for increased intact limb loading by increasing trunk motion, thereby increasing demand on hip abductors to attenuate this preferential loading.     

High-Intensity Interval Training in Cardiac Rehabilitation: Impact on Fat Mass in Patients With Myocardial Infarction

ObjectiveTo examine the effect of high-intensity interval training (HIIT) on body fat mass and distribution in patients with myocardial infarction (MI) who underwent cardiac rehabilitation (CR).Patients and MethodsWe retrospectively screened 391 consecutive patients with MI enrolled in CR between September 1, 2015, and February 28, 2018. We included 120 patients who completed 36 CR sessions and underwent pretest-posttest dual-energy x-ray absorptiometry; 90 engaged in HIIT, and 30 engaged in moderate-intensity continuous training (MICT). High-intensity interval training included 4 to 8 alternating intervals of high- (30-60 seconds at a rating of perceived exertion [RPE] of 15-17 [Borg scale range, 6-20]) and low-intensity (1-5 minutes at RPE <14), and MICT performed for 20 to 45 minutes of exercise at an RPE of 12 to 14. Body weight, fat mass, and lean mass were measured via dual-energy x-ray absorptiometry with lipid profile measured via clinical procedures.ResultsThe HIIT and MICT groups were similar in age (67 vs 67 years), sex (26.7% [24 of 90 patients in the HIIT group] vs 26.7% [8 of 30 in the MICT group), and body mass index (30.3 vs 29.5 kg/m²) at baseline. The HIIT group had greater reductions in body fat percentage (P<.001), fat mass (P<.001), abdominal fat percentage (P<.001), waist circumference (P=.01), total cholesterol (P=.002), low-density lipoprotein cholesterol (P<.001), and triglycerides (P=.006). Improvements in total body mass and body mass index were not different across groups. After matching exercise duration, exercise intensity, and energy expenditure, HIIT-induced improvements in total fat mass (P=.02), body fat percentage (P=.01), and abdominal fat percentage (P=.02) persisted.ConclusionOur data suggest that supervised HIIT results in significant reductions in total fat mass (P<.001) and abdominal fat percentage (P<.001) and improved lipid profile in patients with MI who undergo CR.     

Postamputation Cognitive Impairment Is Related to Worse Perceived Physical Function Among Middle-Aged and Older Prosthesis Users

ObjectiveTo compare characteristics between middle-aged and older prosthesis users with and without cognitive impairment and determine whether cognitive impairment contributes to variability in perceived physical function.DesignCross-sectional, observational studySettingGeneral community.ParticipantsAdults 45 years or older, at least 1-year post lower limb amputation (LLA) who were walking independently with a prosthesis (N=119).InterventionNot applicable.Main Outcome MeasuresWe identified cognitive impairment using an education-adjusted Telephone Interview for Cognitive Status-modified score. Perceived physical function was measured using the Prosthesis Mobility Questionnaire.ResultsOf 119 participants (mean age, 62.6±8.2 years; male: 89.1%; vascular etiology: 82.4%; years since amputation: 4.9±4.7 years), 28 (23.5%) had cognitive impairment. Compared with participants without cognitive impairment, those with cognitive impairment were more likely to use an assistive device (60.7% vs 25.3%, P=.002); were older (66.3±7.3 vs 61.5±8.1 years, P=.006) and had more chronic conditions (7.1±3.4 vs 5.4±2.5, P=.004), more depressive symptoms (6.6±5.1 vs 4.2±3.8, P=.008), and worse perceived physical function (2.0±0.6 vs 2.6±0.7, P<.001). Using backward stepwise linear regression, we found that participants with cognitive impairment had worse perceived physical function (standardized parameter estimate [β]=?0.15, P=.02), even after adjusting for depressive symptoms (β=?0.31, P<.001), prosthesis satisfaction (β=0.34, P<.001), number of chronic conditions (β=?0.19, P=.006), and assistive device use (β_cane=0.01, P=.93; β_other=?0.20, P=.003). Together, these variables explained 59% of perceived physical function variability.ConclusionsCognitive impairment is common and associated with worse perceived physical function post LLA, even after controlling for physical and mental health differences. Tailored rehabilitation interventions may be needed to improve perceived physical function in prosthesis users with cognitive impairment.     

Dosage and Effectiveness of Aerobic Training on Cardiorespiratory Fitness,Functional Capacity,Balance, and Fatigue in People With Multiple Sclerosis: A Systematic Review and Meta-Analysis

ObjectivesTo evaluate the benefits of aerobic training (AT) programs on cardiorespiratory fitness, functional capacity, balance, and fatigue in individuals with multiple sclerosis (MS) and to identify the optimal dosage of AT programs for individuals with MS via a systematic review with meta-analysis.Data sourcesTwo electronic databases were searched until March 2020 (PubMed-Medline and Web of Science).Study SelectionStudies examining the effect of AT program on cardiorespiratory fitness, functional capacity, balance, and fatigue were included.Data ExtractionAfter applying the inclusion and exclusion criteria, we included 43 studies. A total sample of 1070 individuals with MS (AT group, n=680; control group, n=390) were analyzed.Data SynthesisThe AT group demonstrated a significant increase in cardiorespiratory fitness (standardized mean difference [SMD], 0.29; P=.002), functional capacity (timed Up and Go Test: SMD, –1.14; P<.001; gait speed: SMD, –1.19; P<.001; walking endurance: SMD, 0.46; P<.001), and balance (SMD, 3.49; P<.001) after training. Fatigue perception also decreased (SMD, –0.45; P<.001). However, no significant differences were observed when compared with the control group in either cardiorespiratory fitness (SMD, 0.14; P=.19) or fatigue perception. Nevertheless, we observed significant differences between the AT and control groups in balance (P=.02), gait speed (P=.02), and walking endurance (P=.03), favoring the participants who performed AT. Regarding the subgroup analysis, no significant differences were observed between subgroups in any of the variables studied except for gait speed, for which a greater increase in posttraining was observed when the AT program applied the continuous method (χ²=7.75; P=.005) and the exercises were performed by walking (χ²=9.36; P=.002).ConclusionsAerobic training improves gait speed, walking endurance, and balance. Cardiorespiratory fitness and fatigue perception also improved after AT, but we found no differences with the control group. In addition, subgroup analysis suggested that training using continuous and walking methods could optimize gait speed.     

Poster 5: Predictors of fatigue in patients with rheumatoid arthritis and major depressive disorder

Objectives: To determine the relationship between fatigue and disease activity in persons with concomitant rheumatoid arthritis (RA) and major depressive disorder (MDD) and to replicate a previous study that found fatigue was predicted by higher levels of pain, more depressive symptoms, and female gender in a cohort of persons with RA who did not have MDD. Design: Prospective 15-month study using longitudinal data. Setting: Midwestern veterans’ hospital, university medical center, and private rheumatology practice. Participants: 54 subjects (39 women, 15 men) with diagnoses of RA and MDD. Intervention: All participants received a therapeutic dosage of sertraline for their body mass. Outcome measures were collected at 4 time periods: preintervention, and at 3, 6, and 15 months postintervention. Main Outcome Measures: Measures were as follows: Multidimensional Assessment of Fatigue, Center for Epidemiological Studies-Depression scale, pain visual analog scale, Arthritis Activity Today, erythrocyte sedimentation rate, and average sleep over a 3-month period. Results: A multiple regression with fatigue as the dependent variable and pain, depression, and female gender as independent variables demonstrated a replication of the previous study at baseline (R²=.19, P=.015), 3 months (R²=.30, P=.002), 6 months (R²=.55, P<.0001), and 15 months (R²=.52, P<.0001). However, the addition of disease activity and sleep variables in hierarchical fashion found that disease activity and sleep did not make significant contributions above and beyond the replicated model. Conclusions: In this cohort of patients with RA and MDD, higher levels of pain, more depressive symptoms, and female gender were significantly related to fatigue; subjective and objective measures of disease activity, as well as sleep, did not make additive contributions.     

Effect of Increasing Obstacle Distances Task on Postural Stability Variables During Gait Initiation in Older Nonfallers and Fallers

ObjectiveTo compare the scaling of the postural stability variables between older nonfallers and fallers during gait initiation (GI) while stepping over increasing obstacle distances.DesignCross-sectional study.SettingUniversity research laboratory.ParticipantsA sample of participants (N=24) divided into 2 groups: older nonfallers (n=12) and older fallers (n=12). Participants had no known neurologic, musculoskeletal, or cardiovascular conditions that could have affected their walking, and all were independent walkers. All the participants had an adequate cognitive function to participate as indicated by a score of more than 24 on the Mini-Mental State Examination.InterventionsNot applicable.Main Outcome MeasuresThe primary dependent variables were peak anterior-posterior (AP) center of mass (CoM)-center of pressure (CoP) separation during anticipatory postural adjustments (APAs), AP CoM-CoP separation at the toe-off, and peak AP CoM-CoP separation during the swing. Secondary dependent variables were AP trunk angle during GI. Within- and between-repeated measures analysis of variance was used to compare means between groups across different task conditions for all the dependent variables.ResultsThere was a main effect of group for peak AP CoM-CoP separation during APA (P=.018), an interaction effect between group and condition for AP CoM-CoP separation at toe-off (P=.009), and a main effect of condition for peak AP CoM-CoP separation during the swing (P<.001). We also found a main effect of group for peak AP trunk angle during the swing (P=.028).ConclusionsFor GI while stepping over increasing obstacle distances, older fallers adopt a more conservative strategy of AP CoM-CoP separation than nonfallers prior to toe-off and demonstrate increased peak AP trunk lean during the swing. AP CoM-CoP separation prior to toe-off during the GI task may be a critical marker to identify fallers and warrants additional investigation.