Task-oriented exercise effects on walking and corticospinal excitability in multiple sclerosis: protocol for a randomized controlled trial

BACKGROUND

Multiple sclerosis (MS) is a degenerative disease of the central nervous system (CNS) that disrupts walking function and results in other debilitating symptoms. This study compares the effects of 'task-oriented exercise' against 'generalized resistance and aerobic exercise' and a 'stretching control' on walking and CNS function in people with MS (PwMS). We hypothesize that task-oriented exercise will enhance walking speed and related neural changes to a greater extent than other exercise approaches.

METHODS

This study is a single-blinded, three-arm randomized controlled trial conducted in Saskatchewan, Canada. Eligible participants are those older than 18 years of age with a diagnosis of MS and an expanded Patient-Determined Disease Steps (PDDS) score between 3 ('gait disability') and 6 ('bilateral support'). Exercise interventions are delivered for 12 weeks (3 × 60-min per week) in-person under the supervision of a qualified exercise professional. Interventions differ in exercise approach, such that task-oriented exercise involves weight-bearing, walking-specific activities, while generalized resistance and aerobic exercise uses seated machine-based resistance training of major upper and lower body muscle groups and recumbent cycling, and the stretching control exercise involves seated flexibility and relaxation activities. Participants are allocated to interventions using blocked randomization that stratifies by PDDS (mild: 3-4; moderate: 5-6). Assessments are conducted at baseline, post-intervention, and at a six-week retention time point. The primary and secondary outcome measures are the Timed 25-Foot Walk Test and corticospinal excitability for the tibialis anterior muscles determined using transcranial magnetic stimulation (TMS), respectively. Tertiary outcomes include assessments of balance, additional TMS measures, blood biomarkers of neural health and inflammation, and measures of cardiorespiratory and musculoskeletal fitness.

DISCUSSION

A paradigm shift in MS healthcare towards the use of "exercise as medicine" was recently proposed to improve outcomes and alleviate the economic burden of MS. Findings will support this shift by informing the development of specialized exercise programming that targets walking and changes in corticospinal excitability in PwMS.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT05496881, Registered August 11, 2022. https://classic.

CLINICALTRIALS

gov/ct2/show/NCT05496881 . Protocol amendment number: 01; Issue date: August 1, 2023; Primary reason for amendment: Expand eligibility to include people with all forms of MS rather than progressive forms of MS only.

The effect of physical activity on fertility: a mini-review

Although lifestyle factors such as diet, cigarette smoking, and alcohol consumption are increasingly recognized as important contributors to the risk of subfertility, the role of exercise in fertility remains less clear. As such, it is challenging for healthcare providers to deliver clear, evidence-based recommendations to patients regarding the optimal frequency and intensity with which they should exercise to maximize their chances of conception. Therefore, this review provides a critical overview of the available research for various patient populations.

Food Insecurity, Dietary Intakes, and Eating Behaviors in a Convenience Sample of Toronto Youth

BACKGROUND

Food insecurity has been shown to be associated with poor dietary quality and eating behaviors, which can have both short- and long-term adverse health outcomes in children. The objective was to investigate the food security status, dietary intakes, and eating behaviors in a convenience sample of youth participating in the Maple Leaf Sports Entertainment LaunchPad programming in downtown Toronto, Ontario.

METHODS

Youth aged 9-18 years were recruited to participate in the study. Food security status, dietary intakes, and eating behaviors were collected using parent- or self-reported questionnaires online.

RESULTS

Sixty-six youth (mean ± SD: 11.7 ± 1.9 years) participated in the study. The prevalence of household food insecurity was higher than the national average with at least one child under 18 years of age (27.7% vs. 16.2%). Dietary intake patterns were similar to the national trends with low intakes of fiber, inadequate intakes of calcium and vitamin D; and excess intakes of sodium, added sugar, and saturated fat. Despite a low prevalence of poor eating habits, distracted eating was the most frequently reported poor eating habit.

CONCLUSIONS

Although youth were at high risk for experiencing household food insecurity, inadequate dietary intake patterns were similar to the national trends. Our findings can be used to develop future programming to facilitate healthy dietary behaviors appropriate for the target community.

Test-retest reliability and validity of body composition methods in adults

Cost-effective and efficient body composition measurement devices that are reliable and valid are necessary for identifying health risk as well as for understanding the effectiveness of lifestyle interventions. The objective of this study was to evaluate the test-retest reliability and validity of three body composition measurement devices. Forty-nine adults (mean age (SD) = 31.5 (10.7) y; BMI = 23.5 (3.0) kg/m² ) completed a reference air displacement plethysmography (ADP) measure, and duplicate measures using skinfold callipers (Lange), ultrasound (BodyMetrix A-mode) and a 3-dimensional photonic scanner (3DPS; Fit3D ProScanner). Skinfold thickness was measured at seven sites using callipers and ultrasound; percent body fat (%BF) was then estimated using population-specific algorithms. The 3DPS was used to measure body circumferences, and then %BF was estimated using its beta-software. While skinfold callipers showed poor absolute reliability (mean differences (Δ) [95% CI] = 0.54% [0.22, 0.87], standard error of measurement (SEM) = 0.63%), ultrasound and the 3DPS showed excellent absolute (Δ = 0.17% [-0.25, 0.58], SEM = 0.78%; and Δ = -0.01% [-0.43, 0.40], SEM = 0.67%, respectively) and relative reliability (ICC_2,1  = 0.988 [0.979, 0.993]; and ICC_2,1  = 0.983 [0.968, 0.991], respectively). Compared to ADP (n = 43), skinfold callipers underestimated %BF (Δ = -4.53 [-7.72, -1.34]; p = 0.003), while ultrasound (Δ = -0.32 [-3.51, 2.87]; p = 0.99) and the 3DPS (Δ = 1.06 [-2.12. 4.26]; p = 0.77) were not significantly different. Bland-Altman plots showed a minimal bias of ultrasound [95% limit of agreement (LOA) = -7.87, 7.23] and the 3DPS [95% LOA = -6.66, 8.79]. In conclusion, estimating %BF from subcutaneous fat measurements using ultrasound and body circumferences using a 3DPS may be reliable and valid methods that require minimal technician expertise.

Effect of Increasing the Dietary Protein Content of Breakfast on Subjective Appetite, Short-Term Food Intake and Diet-Induced Thermogenesis in Children

Dietary protein affects energy balance by decreasing food intake (FI) and increasing energy expenditure through diet-induced thermogenesis (DIT) in adults. Our objective was to investigate the effects of increasing the dietary protein in an isocaloric breakfast on subjective appetite, FI, blood glucose, and DIT in 9-14 y children. Two randomized repeated measures designs were used. In experiment 1, 17 children (9 boys, 8 girls) consumed isocaloric meals (450 kcal) on four separate mornings containing: 7 g (control), 15 g (low protein, LP), 30 g (medium protein, MP) or 45 g (high protein, HP) of protein. Blood glucose and subjective appetite were measured at baseline and regular intervals for 4 h, and FI was measured at 4 h. In experiment 2, 9 children (6 boys, 3 girls) consumed the control or HP breakfast on two separate mornings, and both DIT and subjective appetite were determined over 5 h. In experiment 1, all dietary protein treatments suppressed subjective appetite compared to control (p < 0.001), and the HP breakfast suppressed FI compared with the LP breakfast and control (p < 0.05). In experiment 2, DIT was higher after HP than control (p < 0.05). In conclusion, increasing the dietary protein content of breakfast had favorable effects on satiety, FI, and DIT in children.

Pre-meal active video game playing increased subjective appetite but not food intake in children and adolescents

OBJECTIVE

Sedentary video game playing (VGP) and caloric preloads in the pre-meal environment have been shown to influence short-term food intake (FI) regulation in children. Other factors that may affect FI control include physical activity and/or heightened emotion. Therefore, we examined the effects of a glucose preload and 30 min of active VGP (aVGP) on subjective appetite, short-term FI, and subjective emotions in 9-14 year-old children.

METHODS

On four test mornings approximately one-week apart, twenty-seven children (sex: 15M, 12F; age: 11.3 ± 0.3 years; BMI percentile: 55.3 ± 6.1%) consumed a standardized breakfast two hours prior to consuming 250 mL of either a 50 g glucose preload or Sucralose® control. Following the preload, participants participated in 30 min of quiet sitting or aVGP. Energy expenditure was measured during aVGP via indirect calorimetry. FI from an ad libitum pizza meal was measured after each test condition. Subjective appetite and emotions were measured at baseline (0 min), during treatment (15min), and immediately before the test meal (30 min).

RESULTS

aVGP did not affect FI, but the glucose preload decreased FI compared with the sucralose control (∆ = 157 kcal, <0.001). Although not statistically significant (p=0.12), caloric compensation was lower following the glucose preload in the aVGP condition. Subjective appetite increased with time, and was higher in the sucralose control + aVGP condition (p=0.05). Change from baseline subjective emotion scores of anger and excitement were higher (p=0.03) and lower (p=0.02) after aVGP, respectively.

CONCLUSIONS

Neither short-term FI nor net energy balance were affected by low-intensity aVGP (energy expenditure of 34 kcal). These findings suggest that a short bout of low-intensity aVGP does not alter energy balance during the study measurement period, and may not support achieving or maintaining healthy weights in children. However, future longitudinal studies are needed to confirm such advice.

Effects of White Potatoes Consumed With Eggs on Satiety, Food Intake, and Glycemic Response in Children and Adolescents

Objective: Short-term studies in adults have shown that white potatoes increase satiety and suppress food intake (FI) compared with several other carbohydrate-containing foods; however, studies are limited in children. The objective was to compare the effects of white potatoes in mixed meals on satiety, FI, and glycemic response in 9-14-year-old children and adolescents.Methods: Using a within-subject, repeated-measures design, 21 children completed five counter-balanced test sessions. After an overnight fast, children consumed one of four isocaloric treatment meals (450 kcal) of French fries, mashed potatoes, or white beans served with a fixed portion of egg omelet (30 g of protein), a control meal with cereal, milk, and bread, or continued to fast (i.e., meal skipping). Subjective appetite was measured using visual analogue scales. FI at an ad libitum pizza meal at 180 min and rest of day diet record were used to measure lunch FI and rest of day energy intake, respectively. Total daily energy intake was calculated by adding the energy intake from the treatment meal, the ad libitum pizza lunch, and rest of day food record. Capillary blood samples were collected to assess glycemic response over 180 min.Results: Change from baseline subjective average appetite scores were lower after mashed potatoes compared with all other treatment conditions (p < 0.001), and higher after French fries compared with white beans (p = 0.04). Lunch FI (kcal) was significantly lower (p < 0.001) after French fries (1010±73) and mashed potatoes (1039±74) compared with the control meal (1257±92) and meal skipping (1235±74). Total daily energy intake (kcal) was lower after French fries compared with the control meal (2228±141 vs. 2624±137; p = 0.04). Change from baseline blood glucose was lower after white beans and French fries compared with mashed potatoes (p < 0.05) and the control meal (p < 0.001).Conclusion: In conclusion, white potatoes with eggs increased satiety, decreased short-term FI, and resulted in similar energy intakes compared with meal skipping.

Effect of potatoes and other carbohydrate-containing foods on cognitive performance, glycemic response, and satiety in children

Dietary carbohydrates have been shown to influence cognitive performance and satiety in children. However, it remains unclear whether the carbohydrate source is a primary determinant of cognitive performance and satiety. The objective was to compare the effects of white potatoes and other carbohydrate-containing foods on cognitive performance, glycemic response, and satiety in children. On 6 separate mornings, in random order, children (n = 22) consumed 50 g of available carbohydrates from microwaved mashed potatoes (prepared from fresh potatoes then frozen), deep-fried potato strips (French fries), hash browns, white rice, white beans, or skipped a meal. Cognitive performance, glycemic response, and satiety were measured over 180 min. Cognitive performance was measured using a battery of tests assessing verbal declarative memory, spatial memory, short-term memory, working memory, and information processing speed. Although cognitive performance after the treatment meals did not differ from meal skipping, children recalled more words after French fries (9.1 ± 0.4 words) compared with mashed potatoes (8.2 ± 0.3 words; p = 0.001) and white rice (8.4 ± 0.3 words; p = 0.04) on the verbal declarative memory test. Blood glucose concentrations were higher after white rice compared with white beans, mashed potatoes, and hash browns (p < 0.05). Change from baseline subjective average appetite (mm/kcal) was lower after mashed potatoes compared with all other treatment meals (p < 0.05). In conclusion, verbal declarative memory was higher after French fries and subjective average appetite was lower after mashed potatoes. Future longitudinal studies are needed to confirm these short-term findings and to elucidate the mechanism of action.

Effect of Commercially Available Sugar-Sweetened Beverages on Subjective Appetite and Short-Term Food Intake in Boys

It is unclear whether sugar sweetened beverages bypass regulatory controls of food intake (FI) in boys. The objective of the present study was to determine the effects of isovolumetric preloads (350 mL) of a fruit-flavoured drink (154 kcal), cola (158 kcal), 1% M.F. chocolate milk (224 kcal), and water (0 kcal) on subjective appetite and FI in boys aged 9–14 years. On four separate mornings, boys consumed one of the preloads in a random order; subjective appetite was measured at 15 min intervals, and FI was measured via an ad libitum pizza lunch at 60 min post-beverage consumption. In the 32 boys (age: 11.8 ± 0.3 years), FI was reduced (p < 0.001) after cola (940 ± 46 kcal) and chocolate milk (878 ± 41 kcal) compared with the water control (1048 ± 35 kcal) and after chocolate milk compared to the fruit drink (1005 ± 44 kcal). Cumulative FI after the fruit drink was greater than the water control (1159 ± 44 vs. 1048 ± 35 kcal; p = 0.03). Average appetite was not affected by the treatment, but the cola treatment resulted in greater fullness (p = 0.04) and lower prospective food consumption (p = 0.004) compared with the fruit drink. In conclusion, chocolate milk and cola suppressed next-meal FI at 60 min, while fruit drink increased cumulative FI (beverage + next meal) over 60 min in boys. Results from this study suggest that beverage composition is an important determinant of FI suppression in boys.

Effect of video game playing and a glucose preload on subjective appetite, subjective emotions, and food intake in overweight and obese boys

Video game playing (VGP) is associated with overweight/obesity (OW/OB). VGP and caloric preloads in the pre-meal environment influence short-term food intake (FI) in healthy-weight children. Therefore, the purpose of the present study was to examine the effect of pre-meal VGP and a glucose preload on subjective emotions, subjective appetite, and FI in boys with OW/OB. On 4 separate mornings, boys with OW/OB (n = 22; mean ± SD: age = 11.9 ± 1.6 years; body mass index percentile = 94.3 ± 3.9) participated in 4 test conditions. Two hours after a standardized breakfast, boys consumed equally sweetened preloads (250 mL) of sucralose (0 kcal) or glucose (200 kcal), with or without 30 min of subsequent VGP. Immediately after each test condition, FI was evaluated during an ad libitum pizza meal. Subjective appetite was measured at 0 (baseline), 15, and 30 min. Subjective emotions (aggression, anger, excitement, disappointment, happiness, upset, and frustration) were measured at 0 and 30 min. VGP did not affect FI, but the glucose preload decreased FI compared with the sucralose control (Δ = -103 ± 48 kcal, p < 0.01). However, cumulative FI (preload kcal + meal kcal) was 9% higher after the glucose preload (p < 0.01). Subjective appetite increased with time (p < 0.05) but was not influenced by preload or VGP. Frustration was the only subjective emotion that increased following VGP (p < 0.01). A glucose preload, but not VGP, suppressed FI in boys with OW/OB, suggesting a primary role of physiological factors in short-term FI regulation.

The effects of whole body vibration on pulse wave velocity in men with chronic spinal cord injury

OBJECTIVE

A pilot study to evaluate the therapeutic potential of 40 weeks of passive standing with whole body vibration (PS-WBV) on central and peripheral arterial stiffness among men with chronic spinal cord injury (SCI).

METHODS

Consenting participants were pre-screened to ensure safe participation. Fifteen individuals with chronic SCI were enrolled to participate in PS-WBV sessions three times per week for 40 weeks on a modified WAVE platform custom-fitted with an EASYStand 5000. Knee angle was set at 160°, and vibration parameters were 45Hz frequency and 0.7mm displacement. Each 45-minute session of PS-WBV training was intermittent (60 seconds on and 120 seconds off). Aortic and leg pulse wave velocity (PWV) was measured at baseline, mid-point (20 weeks) and exit (40 weeks).

RESULTS

Nine males (age 41±11 years, American Spinal Injury Association Impairment Scale A-D, neurological level of injury T4-T10, years post-injury 12±8 years) completed the intervention. Aortic PWV was collected on n=7 at exit, and leg PWV was collected on n=6 at exit. No changes over time were found for either aortic PWV (P = 0.46) or leg PWV (P = 0.54). One possible study-related serious adverse event occurred during study intervention: the development of a grade III pressure sore on the right proximal anterior shin (n=1).

CONCLUSION

Forty weeks of PS-WBV in adults with SCI did not result in an observable change in arterial stiffness.

Pre-meal screen-time activities increase subjective emotions, but not food intake in young girls

PURPOSE

To determine the effect of pre-meal screen-time activities on subjective emotions, subjective appetite, and food intake (FI) in 9-14 year-old girls.

METHODS

In this clinical study, 31 girls completed four 45-min treatment conditions of television viewing (TVV), video game playing (VGP), a challenging computer task (CT), and sitting without screen exposure (control) in a randomized order. Each treatment condition was followed immediately by an ad libitum pizza lunch, and FI was calculated from the weight of the consumed pizza. Subjective appetite was assessed at baseline, 15, 30, and 45 min during the treatment condition, and upon trial completion at 75 min. Subjective emotions were assessed at baseline and at 45 min.

RESULTS

FI was not affected by screen type, but was positively correlated with body composition (fat mass [FM, kg], fat free mass [FFM, kg]) in all treatment conditions. Subjective appetite was not affected by screen type, but increased with time in all treatment conditions (p < 0.0001). Subjective emotions were affected by VGP only. Anger, excitement, frustration, and upset feelings were increased at 45 min following VGP. VGP led to increased frustration compared to control (p = 0.0003), CT (p = 0.007) and TVV (p = 0.0002).

CONCLUSION

Exposure to TVV or CT before eating did not affect subjective emotions, subjective appetite, or FI, and no difference was found between screen activities and the control condition for average appetite or FI. Despite a change in subjective emotions during the VGP condition, there was no increase in subjective appetite or subsequent FI. These findings suggest that physiologic signals of satiation and satiety are not overridden by environmental stimuli of pre-meal screen-time exposure among young girls. (Clinical trial number NCT01750177).

Predicting peak oxygen uptake from submaximal exercise after spinal cord injury

The purpose of this study was to determine the validity of the 6-min arm ergometry test (6MAT) in predicting peak oxygen consumption (V̇O2peak) in individuals with chronic spinal cord injury (SCI). Fifty-two individuals with chronic SCI (age, 38 ± 10 years; American Spinal Injury Association Impairment Scale (AIS), A-D; neurological level of injury (NLI), C1-L2; years post-injury (YPI), 13 ± 10 years) completed an incremental arm ergometry V̇O2peak test and a submaximal 6MAT. Oxygen consumption (V̇O2) data from both tests were used to create a predictive equation with regression analysis. Subsequently, a cross-validation group comprising an additional 10 individuals with SCI (age, 39 ± 13 years; AIS, A-D; NLI, C3-L3; YPI, 9 ± 9 years) were used to determine the predictive power of the equation. All participants were able to complete both the V̇O2peak and 6MAT assessments. Regression analysis yielded the following equation to predict V̇O2peak from end-stage 6MAT V̇O2: V̇O2peak (mL·kg(-1)·min(-1)) = 1.501(6MAT V̇O2) - 0.940. Correlation between measured and predicted V̇O2peak was excellent (r = 0.89). No significant difference was found between measured (17.41 ± 7.44 mL·kg(-1)·min(-1)) and predicted (17.42 ± 6.61 mL·kg(-1)·min(-1)) V̇O2peak (p = 0.97). When cross-validated with a sample of 10 individuals with SCI, correlation between measured and predicted V̇O2peak remained high (r = 0.89), with no differences between measured (18.81 ± 8.35 mL·kg(-1)·min(-1)) and predicted (18.73 ± 7.27 mL·kg(-1)·min(-1)) V̇O2peak (p = 0.75). Results suggest that 6MAT V̇O2 can be used to predict V̇O2peak among individuals with chronic SCI. The 6MAT should be used as a clinical tool for assessing aerobic capacity when peak exercise testing is not feasible.

Following the Physical Activity Guidelines for Adults With Spinal Cord Injury for 16 Weeks Does Not Improve Vascular Health: A Randomized Controlled Trial

OBJECTIVE

To evaluate the effects of following the physical activity guidelines (PAG) for adults with spinal cord injury (SCI) for 16 weeks.

DESIGN

Randomized controlled trial.

SETTING

Community exercise program.

PARTICIPANTS

Individuals with SCI (N=23; neurological level of injury, C3-T11; American Spinal Injury Association Impairment Scale A-C; time postinjury, 12.0±9.9 y; age, 41.4±11.6 y).

INTERVENTIONS

Participants were randomly assigned to PAG training (n=12) or active control (n=11) groups. PAG training involved ≥20 minutes of moderate-vigorous aerobic exercise (rating of perceived exertion 3-6 on 10-point scale) and 3×10 repetitions of upper-body strengthening exercises (50%-70% 1 repetition maximum) 2 times per week. The control group maintained existing physical activity levels with no guidance on training intensity.

MAIN OUTCOME MEASURES

Outcome measures were obtained pre- and postintervention. Vascular health indicators included arterial stiffness via carotid distensibility and pulse wave velocity, and endothelial function via flow-mediated-dilation. Fasted blood samples were analyzed for markers of cardiovascular disease (CVD) risk. Body composition was assessed via anthropometrics and with dual-energy x-ray absorptiometry.

RESULTS

Twenty-one individuals completed the intervention (PAG=12, control=9). Group-by-time interactions were observed for whole-body mass (P=.03), whole-body fat (P=.04), visceral adipose tissue (P=.04), and carotid artery distensibility (P=.05), suggesting maintained body composition and carotid stiffness in the PAG group concurrent with declines in the control group. No changes were found in any other outcome measure.

CONCLUSIONS

While 16 weeks of adherence to the PAG in adults with SCI is insufficient to improve many markers of CVD risk, it may prevent declines in others. The PAG should continue to be promoted as a means to increase physical fitness and maintain body composition in individuals with SCI, but changes may be needed to achieve other health outcomes.

Lower limb conduit artery endothelial responses to acute upper limb exercise in spinal cord injured and able-bodied men

Vascular improvements in the nonactive regions during exercise are likely primarily mediated by increased shear rate (SR). Individuals with spinal cord injury (SCI) experience sublesional vascular deconditioning and could potentially benefit from upper body exercise-induced increases in lower body SR. The present study utilized a single bout of incremental arm-crank exercise to generate exercise-induced SR changes in the superficial femoral artery in an effort to evaluate the acute postexercise impact on superficial femoral artery endothelial function via flow-mediated dilation (FMD), and determine regulatory factors in the nonactive legs of individuals with and without SCI. Eight individuals with SCI and eight age, sex, and waist-circumference-matched able-bodied (AB) controls participated. Nine minutes of incremental arm-crank exercise increased superficial femoral artery anterograde SR (P = 0.02 and P < 0.01), retrograde SR (P < 0.01 and P < 0.01), and oscillatory shear index (OSI) (P < 0.001 and P < 0.001) in both SCI and AB, respectively. However, these SR alterations resulted in acute postexercise increases in FMD in the AB group only (SCI 6.0 ± 1.2% to 6.3 ± 2.7%, P = 0.74; AB 7.5 ± 1.4% to 11.2 ± 1.4%, P = 0.03). While arm exercise has many cardiovascular benefits and results in changes in SR patterns in the nonactive legs, these changes are not sufficient to induce acute changes in FMD among individuals with SCI, and therefore are less likely to stimulate exercise training-associated improvements in nonactive limb endothelial function. Understanding the role of SR patterns on FMD brings us closer to designing effective strategies to combat impaired vascular function in both healthy and clinical populations.

Superficial femoral artery endothelial responses to a short-term altered shear rate intervention in healthy men

In animal and in-vitro models, increased oscillatory shear stress characterized by increased retrograde shear-rate (SR) is associated with acutely decreased endothelial cell function. While previous research suggests a possible detrimental role of elevated retrograde SR on endothelial-function in the brachial artery in humans, little research has been conducted examining arteries in the leg. Examinations of altered shear pattern in the superficial femoral artery (SFA) are important, as this vessel is both prone to atherosclerosis and leg exercise is a common form of activity in humans. Seven healthy men participated; bilateral endothelial-function was assessed via flow-mediated-dilation (FMD) before and after 30-minute unilateral inflations of a thigh blood pressure cuff to either 75 mmHg or 100 mmHg on two separate visits. Inflation of the cuff induced increases in maximum anterograde (p<0.05), maximum retrograde (p<0.01), and oscillatory shear index (OSI) (p<0.001) in the cuffed leg at both inflation pressures. At 100 mmHg the increases in SR were larger in the retrograde than the anterograde direction evidenced by a decrease in mean SR (p<0.01). There was an acute decrease in relative FMD in the cuffed leg alone following inflation to both pressures. These results indicate that in the SFA, altered SR profiles incorporating increased retrograde and OSI influence the attenuation in FMD after a 30-minute unilateral thigh-cuff inflation intervention. Novel information highlighting the importance of OSI calculations and assessments of flow profiles add to current body of knowledge regarding the influence of changes in SR patterns on FMD. Findings from the current study may provide additional insight when designing strategies to combat impaired vascular function in the lower extremity where blood vessels are more prone to atherosclerosis in comparison to the upper extremity.

Measurement precision of body composition variables in elite wheelchair athletes, using dual-energy X-ray absorptiometry

The purpose of this study was to assess the reproducibility of body composition measurements by dual-energy X-ray absorptiometry (DXA) in 12 elite male wheelchair basketball players (age 31 ± 7 years, BMI 21 ± 2 kg/m(2) and onset of disability 25 ± 9 years). Two whole body scans were performed on each participant in the supine position on the same day, using Lunar Prodigy Advance DXA (GE Lunar, Madison, WI, USA). Participants dismounted from the scanning table and were repositioned in-between the first and second scan. Whole body coefficient of variation (CV) values for bone mineral content (BMC), fat mass (FM) and soft tissue lean mass (LTM) were all <2.0%. With the exclusion of arm FM (CV = 7.8%), CV values ranged from 0.1 to 3.7% for all total body and segmental measurements of BMC, FM and LTM. The least significant change that can be attributed to the effect of treatment intervention in an individual is 1.0 kg, 1.1 kg, 0.12 kg for FM, LTM, and BMC, respectively. This information can be used to determine meaningful changes in body composition when assessed using the same methods longitudinally. Whilst there may be challenges in the correct positioning of an individual with disability that can introduce greater measurement error, DXA is a highly reproducible technique in the estimation of total and regional body composition of elite wheelchair basketball athletes.

Whole-body vibration as potential intervention for people with low bone mineral density and osteoporosis: a review

Low bone mineral density (BMD) and osteoporosis are health concerns among older adults and individuals with physical, neurological, and/or mobility impairments. Detrimental changes in bone density and bone architecture occurring in these individuals may be due in part to the reduction/cessation of physical activity and the accompanying reduction of mechanical strain on bone. Changes in bone architecture predispose these individuals to fragility fractures during low-trauma events. Whole-body vibration (WBV) has been examined as an intervention for maintaining or improving bone mass among people with low BMD, because it may emulate the mechanical strains observed during normal daily activities. This article provides an overview of WBV including terminology, safety considerations, and a summary of the current literature; it is intended for rehabilitation healthcare providers considering WBV as a potential therapy for individuals with osteoporosis.