Three-dimensional motion of the center of mass and energetic cost across a variety of walking speeds : a comparison between adults with and without Down syndrome

It has been previously suggested that the walking pattern of individuals with Down syndrome is inefficient. This is thought to result from increased instability, particularly in the medio-lateral direction, due to the characteristic joint laxity and muscle hypotonia of individuals with DS. Therefore, this work was an attempt to gain insight into the efficiency of gait in adults with DS by studying their mechanical and metabolic characteristics during treadmill walking. The first study examined the three-dimensional motion of the center of mass (COM) and the spatio-temporal characteristics of adults with and without DS at a variety of walking speeds. Fifteen adults with DS and 15 adults without DS walked on a treadmill at six and seven randomly presented dimensionless speeds (Froude numbers), respectively, during which kinematic data were collected. The range of medio-lateral COM position was greater in participants with DS, but the ranges of vertical COM position and anterior-posterior COM velocity did not differ between the groups. Participants with DS walked with faster steps across all speeds. Their step length was shorter only during slow walking and their step width did not differ from adults without DS. Participants with DS were more variable in medio-lateral and vertical COM position, anterior-posterior COM velocity, and in all spatio-temporal parameters than their controls. The second study examined whether the net VO₂ and the net VO₂ per unit distance across the same walking speeds are different between adults with and without DS. The study also examined the relationship between the energetically optimal walking speed (EOWS) and the preferred walking speed (PWS) in both populations. Respiratory gases were collected from 14 adults with DS and 15 adults without DS as they walked at the same Froude numbers as for the first study. Adults with DS showed a higher net VO₂ and net VO₂ per unit distance, and a slower EOWS compared to adults without DS. The PWS was the same for both groups and did not appear to minimize the net VO₂ per unit distance in adults with DS. It was collectively concluded that the gait of adults with DS possesses several characteristics of inefficiency and has increased energetic requirements. Adults with DS do not prefer to walk at speeds that minimize the metabolic demand

Opportunities, barriers, and recommendations in down syndrome research

Recent advances in medical care have increased life expectancy and improved the quality of life for people with Down syndrome (DS). These advances are the result of both pre-clinical and clinical research but much about DS is still poorly understood. In 2020, the NIH announced their plan to update their DS research plan and requested input from the scientific and advocacy community. The National Down Syndrome Society (NDSS) and the LuMind IDSC Foundation worked together with scientific and medical experts to develop recommendations for the NIH research plan. NDSS and LuMind IDSC assembled over 50 experts across multiple disciplines and organized them in eleven working groups focused on specific issues for people with DS. This review article summarizes the research gaps and recommendations that have the potential to improve the health and quality of life for people with DS within the next decade. This review highlights many of the scientific gaps that exist in DS research. Based on these gaps, a multidisciplinary group of DS experts has made recommendations to advance DS research. This paper may also aid policymakers and the DS community to build a comprehensive national DS research strategy

GENEACTIV ACCELEROMETER CUT POINTS FOR ADULTS WITH DOWN SYNDROME

BACKGROUND: Accelerometer cut-points specific to adults with Down syndrome (DS) may improve the measurement of physical activity and sedentary behavior in this population. The purpose of the study was to generate cut-points for sedentary behavior and moderate and vigorous PA for adults with DS based on raw acceleration data from a GENEactiv hip accelerometer. METHODS: Thirty-five adults with DS (age 35 ± 8 years; 19 men) performed 17 tasks each lasting 6 min: sitting; watching a movie; playing app on tablet; drawing; standing; folding clothes; vacuuming; sweeping; moving a box; basketball; soccer; fitness circuit; dancing; walking at the preferred speed and at 0.8 and 1.4 m.s-1; and running. Oxygen uptake was measured with portable calorimetry (K5, Cosmed). One metabolic equivalent (MET) was operationalized as VO2 during sitting allowing for determination of METs during each task. A GENEactiv accelerometer worn on the non-dominant hip was used to determine the Vector Magnitude of raw acceleration data. Vector Magnitudecut-points for sedentary behavior (≤1.5 METs while sitting) and for moderate (3.0­-5.9 METs) and vigorous (≥6 METs) physical activity were determined with Receiver Operating Characteristic (ROC) curves. Classification performance was evaluated with the area under the ROC curve. Youden’s index was used to identify optimal cut-points maximizing sensitivity and specificity. RESULTS: Area under the ROC curve was: (a) sedentary behavior (0.94; 95% CI: 0.92 - 0.96); (b) moderate physical activity (0.85; 95% CI: 0.82 - 0.87); and (c) vigorous physical activity (0.79; 95% CI: 0.71 - 0.87). Vector Magnitude cut-points were: (a) sedentary behavior ≤160 g∙min-1 (sensitivity 1.00; specificity 0.81; Youden’s index 0.81); (b) moderate physical activity ≥320 g∙min-1 (sensitivity 0.96; specificity 0.65; Youden’s index 0.61); and (c) vigorous physical activity ≥1211 g∙min-1 (sensitivity 0.58; specificity 0.87; Youden’s index 0.45). CONCLUSIONS: ROC models for sedentary behavior and moderate and vigorous physical activity intensity based on raw acceleration data for a hip-worn GENEactiv accelerometer have acceptable classification accuracy in adults with DS.Funding: NIH Grant R15HD09866

MODERATION OF BODY FAT ON THE RELATIONSHIP BETWEEN AGE AND ARTERIAL STIFFNESS IN DOWN SYNDROME

BACKGROUND: Adults with Down syndrome (DS) have high levels of BF% despite attenuated increases in arterial stiffness compared to adults without DS, indicating that BF% may not contribute to increased arterial stiffness in this population. This study investigated the associations between age, BF%, and arterial stiffness, and the moderation of BF% on the relationship between age and arterial stiffness in adults with and without DS. METHODS: Thirty-three adults with DS (age 36±11 years) and 58 adults without DS (age 28±11 years) underwent measurements of BF% by bioelectrical impedance and carotid-femoral pulse wave velocity (CF-PWV) by applanation tonometry. Pearson’s correlation was used to examine the associations between age, body composition, and arterial stiffness. Moderation analysis was performed to determine if BF% moderates the relationship between age and arterial stiffness in adults with and without DS. RESULTS: Age was significantly associated with BF% (r=.33, p=.006) and CF-PWV (r=.71, p=\u3c.001), and %BF was significantly associated with CF-PWV (r=.43, p\u3c.001) in adults without DS. In adults with DS, age was significantly correlated with CF-PWV (r=.59, p\u3c.001). BF% was not associated with age (r=-.02, p=.453) or CF-PWV (r=.13, p=.233). Moderation analysis showed significant main effects of age (β=.49, 95%CI [.24, .74], p\u3c.001) and BF% (β=.28, 95%CI [.08, .48], p=.007) in adults without DS. Simple slopes analysis demonstrated that, in adults without DS with low BF% (-1SD), age had a non-significant impact on CF-PWV (β=.25, 95%CI [-.22, .72], p=.295). For those with average BF%, age had a significant impact on CF-PWV (β=.49, 95%CI [.24, .74], p\u3c.001) and for those with high BF% (+1SD) the significant impact of age on CF-PWV became even larger (β=.72, 95%CI [.51, .93], p\u3c.001). In adults with DS, the main effect of age on CF-PWV was significant (β=.69, 95%CI [.36, 1.02], p\u3c.001); however, the effect of BF% was not significant (β=.16, 95%CI [-.14, .45], p=.285). CONCLUSION: The relationship between arterial stiffness and %BF differs between adults with and without DS. In adults without DS, increased BF% increases the impact of age on arterial stiffness. Body composition does not appear to significantly contribute to the age-related increases in arterial stiffness in adults with DS.Funding: MSU ORED and I’m An Athlete Foundatio

Accelerometer cut points for adults with down syndrome

Past research has indicated that the relationship between energy expenditure and accelerometer output is different between adults with and without Down syndrome (DS). This suggests a need for DS-specific cut points for determining levels of sedentary behavior and physical activity from accelerometer output for adults with DS. To develop accelerometer output cut points for sedentary behavior and moderate and vigorous intensity physical activity for adults with DS. Sixteen adults with DS (10 men & 6 women; age 31 ± 15 years) performed 12 tasks each lasting 6 min: sitting; playing app on tablet; drawing; folding clothes; sweeping; fitness circuit; moving a box; basketball; standing; and walking at the preferred speed and at 0.8 and 1.4 m.s-1. We measured the rate of oxygen uptake with portable indirect calorimetry (K4b2, Cosmed) and expressed it in Metabolic Equivalents (METs). Output from a triaxial accelerometer (wGT3X-BT, Actigraph) worn on the non-dominant hip was determined as Vector Magnitude. Receiver Operating Characteristic (ROC) curves were used to identify Vector Magnitude cut points for sedentary behavior and moderate (3.0 - 5.99 METs) and vigorous (≥6 METs) intensity physical activity. Overall performance of classification models was assessed with the area under the ROC curve. Optimal cut points maximizing sensitivity and specificity were selected based on Youden’s index. Area under the ROC curve was high for all models: (a) sedentary behavior (0.96; 95% CI: 0.93 - 0.98); (b) moderate intensity physical activity (0.92; 95% CI: 0.88 - 0.96); and (c) vigorous intensity physical activity (0.92; 95% CI: 0.85 - 0.99). The optimal Vector Magnitude cut points were: (a) sedentary behavior ≤236 counts·min-1 (sensitivity 0.98; specificity 0.90; Youden’s index 0.88); (b) moderate-intensity physical activity ≤2167 counts·min-1 (sensitivity 0.99; specificity 0.82; Youden’s index 0.81); and (c) vigorous-intensity physical activity ≥4200 counts·min-1 (sensitivity 1.00; specificity 0.84; Youden’s index 0.84). This study offers the first DS-specific accelerometer output cut-points for classifying sedentary behavior and intensity of physical activity in adults with DS. Overall classification accuracy was excellent527

Development and cross-validation of a Bmi-based equation for percent fat in children with intellectual disability

sem informação527S876876FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP2019/07103-6; 2018/02795-4; 2018/02677-1; 2017/13071-4American-College-of-Sports-Medicine (ACSM) Virtual Conference202