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The constrained total energy expenditure (TEE) model posits that progressive increases in physical activity (PA) lead to increases in TEE; but after certain PA threshold, TEE plateaus. Then, a compensatory reduction in the expenditure of non-essential activities constrains the TEE. We hypothesized that high PA levels as locomotion associate with a compensatory attenuation in arm movements. We included 209 adults (64% females, mean [SD] age 32.1 [15.0] years) and 105 children (40% females, age 10.0 [1.1] years). Subjects wore, simultaneously, one accelerometer in the non-dominant wrist and another in the hip for >= 4 days. We analyzed the association between wrist-measured (arm movements plus locomotion) and hip-measured PA (locomotion). We also analyzed how the capacity to dissociate arm movements from locomotion influences total PA. In adults, the association between wrist-measured and hip-measured PA was better described by a quadratic than a linear model (Quadratic-R-2=0.54 vs. Linear-R-2=0.52; P=0.003). Above the 80th percentile of hip-measured PA, wrist-measured PA plateaued. In children, there was no evidence that a quadratic model fitted the association between wrist-measured and hip-measured PA better than a linear model (R-2=0.58 in both models, P=0.25). In adults and children, those with the highest capacity to dissociate arm movements from locomotion-i.e. higher arm movements for a given locomotion-reached the highest total PA. We conclude that, in adults, elevated locomotion associates with a compensatory reduction in arm movements (probably non-essential fidgeting) that partially explains the constrained TEE model. Subjects with the lowest arm compensation reach the highest total PA., Funding Agencies|Fondo Nacional de Desarrollo Cientifico y TecnologicoComision Nacional de Investigacion Cientifica y Tecnologica (CONICYT)CONICYT FONDECYT [11180361]; Spanish Ministry of Education, Culture and Sport [FPU15/04059, FPU15/02645, FPU14/04172]; University of Granada; Spanish Ministry of Economy and Competitiveness; Fondo de Investigacion Sanitaria del Instituto de Salud Carlos IIIInstituto de Salud Carlos III [PI13/01393]; Junta de Andalucia, Consejeria de Conocimiento, Investigacion y UniversidadesJunta de Andalucia; European Regional Development Funds (FEDER)European Commission [SOMM17/6107/UGR]; Redes Tematicas de Investigacion Cooperativa RETIC [Red SAMID RD16/0022]; EXERNET Research Network on Exercise and Health in Special Populations [DEP2005-00046/ACTI]; Fundacion Iberoamericana de Nutricion (ACTIBATE study); AstraZeneca HealthCare Foundation (ACTIBATE study); [PTA 12264-I]

Accelerometers accuracy for sedentary time (ST) and moderate-to-vigorous physical activity (MVPA) classification depends on accelerometer placement, data processing, activities, and sample characteristics. As intensities differ by age, this study sought to determine intensity cut-points at various wear locations people more than 70 years old. Data from 59 older adults were used for calibration and from 21 independent participants for cross-validation purposes. Participants wore accelerometers on their hip and wrists while performing activities and having their energy expenditure measured with portable calorimetry. ST and MVPA were defined as <= 1.5 metabolic equivalents (METs) and >= 3 METs (1 MET = 2.8 mL/kg/min), respectively. Receiver operator characteristic (ROC) analyses showed fair-to-good accuracy (area under the curve [AUC] = 0.62-0.89). ST cut-points were 7 mg (cross-validation: sensitivity = 0.88, specificity = 0.80) and 1 count/5 s (cross-validation: sensitivity = 0.91, specificity = 0.96) for the hip; 18 mg (cross-validation: sensitivity = 0.86, specificity = 0.86) and 102 counts/5 s (cross-validation: sensitivity = 0.91, specificity = 0.92) for the non-dominant wrist; and 22 mg and 175 counts/5 s (not cross-validated) for the dominant wrist. MVPA cut-points were 14 mg (cross-validation: sensitivity = 0.70, specificity = 0.99) and 54 count/5 s (cross-validation: sensitivity = 1.00, specificity = 0.96) for the hip; 60 mg (cross-validation: sensitivity = 0.83, specificity = 0.99) and 182 counts/5 s (cross-validation: sensitivity = 1.00, specificity = 0.89) for the non-dominant wrist; and 64 mg and 268 counts/5 s (not cross-validated) for the dominant wrist. These cut-points can classify ST and MVPA in older adults from hip- and wrist-worn accelerometers., Funding Agencies|University of Pittsburgh Claude D. Pepper Older Americans Independence Center, Research Registry and Developmental Pilot Grant [NIH P30 AG024827]; National Institute on Aging Professional Services [HHSN271201100605P]; Intramural Research Program of the National Institutes of Health, National Institute on AgingUnited States Department of Health & Human ServicesNational Institutes of Health (NIH) - USANIH National Institute on Aging (NIA); National Institutes of HealthUnited States Department of Health & Human ServicesNational Institutes of Health (NIH) - USA [AG000181, AG036594]; Biomedical Research Networking Center on Frailty and Healthy Aging (CIBERFES); FEDER funds from the European UnionEuropean Commission [CB16/10/00477]; Spanish Ministry of Science and InnovationSpanish Government [FJC2018-037925-I]; Plan Propio de Investigacion 2020 from the University of Granada-Programa Contratos-Puente

The constrained total energy expenditure (TEE) model posits that progressive increases in physical activity (PA) lead to increases in TEE; but after certain PA threshold, TEE plateaus. Then, a compensatory reduction in the expenditure of non-essential activities constrains the TEE. We hypothesized that high PA levels as locomotion associate with a compensatory attenuation in arm movements. We included 209 adults (64% females, mean [SD] age 32.1 [15.0] years) and 105 children (40% females, age 10.0 [1.1] years). Subjects wore, simultaneously, one accelerometer in the non-dominant wrist and another in the hip for >= 4 days. We analyzed the association between wrist-measured (arm movements plus locomotion) and hip-measured PA (locomotion). We also analyzed how the capacity to dissociate arm movements from locomotion influences total PA. In adults, the association between wrist-measured and hip-measured PA was better described by a quadratic than a linear model (Quadratic-R-2=0.54 vs. Linear-R-2=0.52; P=0.003). Above the 80th percentile of hip-measured PA, wrist-measured PA plateaued. In children, there was no evidence that a quadratic model fitted the association between wrist-measured and hip-measured PA better than a linear model (R-2=0.58 in both models, P=0.25). In adults and children, those with the highest capacity to dissociate arm movements from locomotion-i.e. higher arm movements for a given locomotion-reached the highest total PA. We conclude that, in adults, elevated locomotion associates with a compensatory reduction in arm movements (probably non-essential fidgeting) that partially explains the constrained TEE model. Subjects with the lowest arm compensation reach the highest total PA., Funding Agencies|Fondo Nacional de Desarrollo Cientifico y TecnologicoComision Nacional de Investigacion Cientifica y Tecnologica (CONICYT)CONICYT FONDECYT [11180361]; Spanish Ministry of Education, Culture and Sport [FPU15/04059, FPU15/02645, FPU14/04172]; University of Granada; Spanish Ministry of Economy and Competitiveness; Fondo de Investigacion Sanitaria del Instituto de Salud Carlos IIIInstituto de Salud Carlos III [PI13/01393]; Junta de Andalucia, Consejeria de Conocimiento, Investigacion y UniversidadesJunta de Andalucia; European Regional Development Funds (FEDER)European Commission [SOMM17/6107/UGR]; Redes Tematicas de Investigacion Cooperativa RETIC [Red SAMID RD16/0022]; EXERNET Research Network on Exercise and Health in Special Populations [DEP2005-00046/ACTI]; Fundacion Iberoamericana de Nutricion (ACTIBATE study); AstraZeneca HealthCare Foundation (ACTIBATE study); [PTA 12264-I]

The constrained total energy expenditure (TEE) model posits that progressive increases in physical activity (PA) lead to increases in TEE; but after certain PA threshold, TEE plateaus. Then, a compensatory reduction in the expenditure of non-essential activities constrains the TEE. We hypothesized that high PA levels as locomotion associate with a compensatory attenuation in arm movements. We included 209 adults (64% females, mean [SD] age 32.1 [15.0] years) and 105 children (40% females, age 10.0 [1.1] years). Subjects wore, simultaneously, one accelerometer in the non-dominant wrist and another in the hip for >= 4 days. We analyzed the association between wrist-measured (arm movements plus locomotion) and hip-measured PA (locomotion). We also analyzed how the capacity to dissociate arm movements from locomotion influences total PA. In adults, the association between wrist-measured and hip-measured PA was better described by a quadratic than a linear model (Quadratic-R-2=0.54 vs. Linear-R-2=0.52; P=0.003). Above the 80th percentile of hip-measured PA, wrist-measured PA plateaued. In children, there was no evidence that a quadratic model fitted the association between wrist-measured and hip-measured PA better than a linear model (R-2=0.58 in both models, P=0.25). In adults and children, those with the highest capacity to dissociate arm movements from locomotion-i.e. higher arm movements for a given locomotion-reached the highest total PA. We conclude that, in adults, elevated locomotion associates with a compensatory reduction in arm movements (probably non-essential fidgeting) that partially explains the constrained TEE model. Subjects with the lowest arm compensation reach the highest total PA., Funding Agencies|Fondo Nacional de Desarrollo Cientifico y TecnologicoComision Nacional de Investigacion Cientifica y Tecnologica (CONICYT)CONICYT FONDECYT [11180361]; Spanish Ministry of Education, Culture and Sport [FPU15/04059, FPU15/02645, FPU14/04172]; University of Granada; Spanish Ministry of Economy and Competitiveness; Fondo de Investigacion Sanitaria del Instituto de Salud Carlos IIIInstituto de Salud Carlos III [PI13/01393]; Junta de Andalucia, Consejeria de Conocimiento, Investigacion y UniversidadesJunta de Andalucia; European Regional Development Funds (FEDER)European Commission [SOMM17/6107/UGR]; Redes Tematicas de Investigacion Cooperativa RETIC [Red SAMID RD16/0022]; EXERNET Research Network on Exercise and Health in Special Populations [DEP2005-00046/ACTI]; Fundacion Iberoamericana de Nutricion (ACTIBATE study); AstraZeneca HealthCare Foundation (ACTIBATE study); [PTA 12264-I]

Accelerometers accuracy for sedentary time (ST) and moderate-to-vigorous physical activity (MVPA) classification depends on accelerometer placement, data processing, activities, and sample characteristics. As intensities differ by age, this study sought to determine intensity cut-points at various wear locations people more than 70 years old. Data from 59 older adults were used for calibration and from 21 independent participants for cross-validation purposes. Participants wore accelerometers on their hip and wrists while performing activities and having their energy expenditure measured with portable calorimetry. ST and MVPA were defined as <= 1.5 metabolic equivalents (METs) and >= 3 METs (1 MET = 2.8 mL/kg/min), respectively. Receiver operator characteristic (ROC) analyses showed fair-to-good accuracy (area under the curve [AUC] = 0.62-0.89). ST cut-points were 7 mg (cross-validation: sensitivity = 0.88, specificity = 0.80) and 1 count/5 s (cross-validation: sensitivity = 0.91, specificity = 0.96) for the hip; 18 mg (cross-validation: sensitivity = 0.86, specificity = 0.86) and 102 counts/5 s (cross-validation: sensitivity = 0.91, specificity = 0.92) for the non-dominant wrist; and 22 mg and 175 counts/5 s (not cross-validated) for the dominant wrist. MVPA cut-points were 14 mg (cross-validation: sensitivity = 0.70, specificity = 0.99) and 54 count/5 s (cross-validation: sensitivity = 1.00, specificity = 0.96) for the hip; 60 mg (cross-validation: sensitivity = 0.83, specificity = 0.99) and 182 counts/5 s (cross-validation: sensitivity = 1.00, specificity = 0.89) for the non-dominant wrist; and 64 mg and 268 counts/5 s (not cross-validated) for the dominant wrist. These cut-points can classify ST and MVPA in older adults from hip- and wrist-worn accelerometers., Funding Agencies|University of Pittsburgh Claude D. Pepper Older Americans Independence Center, Research Registry and Developmental Pilot Grant [NIH P30 AG024827]; National Institute on Aging Professional Services [HHSN271201100605P]; Intramural Research Program of the National Institutes of Health, National Institute on AgingUnited States Department of Health & Human ServicesNational Institutes of Health (NIH) - USANIH National Institute on Aging (NIA); National Institutes of HealthUnited States Department of Health & Human ServicesNational Institutes of Health (NIH) - USA [AG000181, AG036594]; Biomedical Research Networking Center on Frailty and Healthy Aging (CIBERFES); FEDER funds from the European UnionEuropean Commission [CB16/10/00477]; Spanish Ministry of Science and InnovationSpanish Government [FJC2018-037925-I]; Plan Propio de Investigacion 2020 from the University of Granada-Programa Contratos-Puente

Accelerometers accuracy for sedentary time (ST) and moderate-to-vigorous physical activity (MVPA) classification depends on accelerometer placement, data processing, activities, and sample characteristics. As intensities differ by age, this study sought to determine intensity cut-points at various wear locations people more than 70 years old. Data from 59 older adults were used for calibration and from 21 independent participants for cross-validation purposes. Participants wore accelerometers on their hip and wrists while performing activities and having their energy expenditure measured with portable calorimetry. ST and MVPA were defined as <= 1.5 metabolic equivalents (METs) and >= 3 METs (1 MET = 2.8 mL/kg/min), respectively. Receiver operator characteristic (ROC) analyses showed fair-to-good accuracy (area under the curve [AUC] = 0.62-0.89). ST cut-points were 7 mg (cross-validation: sensitivity = 0.88, specificity = 0.80) and 1 count/5 s (cross-validation: sensitivity = 0.91, specificity = 0.96) for the hip; 18 mg (cross-validation: sensitivity = 0.86, specificity = 0.86) and 102 counts/5 s (cross-validation: sensitivity = 0.91, specificity = 0.92) for the non-dominant wrist; and 22 mg and 175 counts/5 s (not cross-validated) for the dominant wrist. MVPA cut-points were 14 mg (cross-validation: sensitivity = 0.70, specificity = 0.99) and 54 count/5 s (cross-validation: sensitivity = 1.00, specificity = 0.96) for the hip; 60 mg (cross-validation: sensitivity = 0.83, specificity = 0.99) and 182 counts/5 s (cross-validation: sensitivity = 1.00, specificity = 0.89) for the non-dominant wrist; and 64 mg and 268 counts/5 s (not cross-validated) for the dominant wrist. These cut-points can classify ST and MVPA in older adults from hip- and wrist-worn accelerometers., Funding Agencies|University of Pittsburgh Claude D. Pepper Older Americans Independence Center, Research Registry and Developmental Pilot Grant [NIH P30 AG024827]; National Institute on Aging Professional Services [HHSN271201100605P]; Intramural Research Program of the National Institutes of Health, National Institute on AgingUnited States Department of Health & Human ServicesNational Institutes of Health (NIH) - USANIH National Institute on Aging (NIA); National Institutes of HealthUnited States Department of Health & Human ServicesNational Institutes of Health (NIH) - USA [AG000181, AG036594]; Biomedical Research Networking Center on Frailty and Healthy Aging (CIBERFES); FEDER funds from the European UnionEuropean Commission [CB16/10/00477]; Spanish Ministry of Science and InnovationSpanish Government [FJC2018-037925-I]; Plan Propio de Investigacion 2020 from the University of Granada-Programa Contratos-Puente

The constrained total energy expenditure (TEE) model posits that progressive increases in physical activity (PA) lead to increases in TEE; but after certain PA threshold, TEE plateaus. Then, a compensatory reduction in the expenditure of non-essential activities constrains the TEE. We hypothesized that high PA levels as locomotion associate with a compensatory attenuation in arm movements. We included 209 adults (64% females, mean [SD] age 32.1 [15.0] years) and 105 children (40% females, age 10.0 [1.1] years). Subjects wore, simultaneously, one accelerometer in the non-dominant wrist and another in the hip for >= 4 days. We analyzed the association between wrist-measured (arm movements plus locomotion) and hip-measured PA (locomotion). We also analyzed how the capacity to dissociate arm movements from locomotion influences total PA. In adults, the association between wrist-measured and hip-measured PA was better described by a quadratic than a linear model (Quadratic-R-2=0.54 vs. Linear-R-2=0.52; P=0.003). Above the 80th percentile of hip-measured PA, wrist-measured PA plateaued. In children, there was no evidence that a quadratic model fitted the association between wrist-measured and hip-measured PA better than a linear model (R-2=0.58 in both models, P=0.25). In adults and children, those with the highest capacity to dissociate arm movements from locomotion-i.e. higher arm movements for a given locomotion-reached the highest total PA. We conclude that, in adults, elevated locomotion associates with a compensatory reduction in arm movements (probably non-essential fidgeting) that partially explains the constrained TEE model. Subjects with the lowest arm compensation reach the highest total PA., Funding Agencies|Fondo Nacional de Desarrollo Cientifico y TecnologicoComision Nacional de Investigacion Cientifica y Tecnologica (CONICYT)CONICYT FONDECYT [11180361]; Spanish Ministry of Education, Culture and Sport [FPU15/04059, FPU15/02645, FPU14/04172]; University of Granada; Spanish Ministry of Economy and Competitiveness; Fondo de Investigacion Sanitaria del Instituto de Salud Carlos IIIInstituto de Salud Carlos III [PI13/01393]; Junta de Andalucia, Consejeria de Conocimiento, Investigacion y UniversidadesJunta de Andalucia; European Regional Development Funds (FEDER)European Commission [SOMM17/6107/UGR]; Redes Tematicas de Investigacion Cooperativa RETIC [Red SAMID RD16/0022]; EXERNET Research Network on Exercise and Health in Special Populations [DEP2005-00046/ACTI]; Fundacion Iberoamericana de Nutricion (ACTIBATE study); AstraZeneca HealthCare Foundation (ACTIBATE study); [PTA 12264-I]

Accelerometers accuracy for sedentary time (ST) and moderate-to-vigorous physical activity (MVPA) classification depends on accelerometer placement, data processing, activities, and sample characteristics. As intensities differ by age, this study sought to determine intensity cut-points at various wear locations people more than 70 years old. Data from 59 older adults were used for calibration and from 21 independent participants for cross-validation purposes. Participants wore accelerometers on their hip and wrists while performing activities and having their energy expenditure measured with portable calorimetry. ST and MVPA were defined as <= 1.5 metabolic equivalents (METs) and >= 3 METs (1 MET = 2.8 mL/kg/min), respectively. Receiver operator characteristic (ROC) analyses showed fair-to-good accuracy (area under the curve [AUC] = 0.62-0.89). ST cut-points were 7 mg (cross-validation: sensitivity = 0.88, specificity = 0.80) and 1 count/5 s (cross-validation: sensitivity = 0.91, specificity = 0.96) for the hip; 18 mg (cross-validation: sensitivity = 0.86, specificity = 0.86) and 102 counts/5 s (cross-validation: sensitivity = 0.91, specificity = 0.92) for the non-dominant wrist; and 22 mg and 175 counts/5 s (not cross-validated) for the dominant wrist. MVPA cut-points were 14 mg (cross-validation: sensitivity = 0.70, specificity = 0.99) and 54 count/5 s (cross-validation: sensitivity = 1.00, specificity = 0.96) for the hip; 60 mg (cross-validation: sensitivity = 0.83, specificity = 0.99) and 182 counts/5 s (cross-validation: sensitivity = 1.00, specificity = 0.89) for the non-dominant wrist; and 64 mg and 268 counts/5 s (not cross-validated) for the dominant wrist. These cut-points can classify ST and MVPA in older adults from hip- and wrist-worn accelerometers., Funding Agencies|University of Pittsburgh Claude D. Pepper Older Americans Independence Center, Research Registry and Developmental Pilot Grant [NIH P30 AG024827]; National Institute on Aging Professional Services [HHSN271201100605P]; Intramural Research Program of the National Institutes of Health, National Institute on AgingUnited States Department of Health & Human ServicesNational Institutes of Health (NIH) - USANIH National Institute on Aging (NIA); National Institutes of HealthUnited States Department of Health & Human ServicesNational Institutes of Health (NIH) - USA [AG000181, AG036594]; Biomedical Research Networking Center on Frailty and Healthy Aging (CIBERFES); FEDER funds from the European UnionEuropean Commission [CB16/10/00477]; Spanish Ministry of Science and InnovationSpanish Government [FJC2018-037925-I]; Plan Propio de Investigacion 2020 from the University of Granada-Programa Contratos-Puente

The constrained total energy expenditure (TEE) model posits that progressive increases in physical activity (PA) lead to increases in TEE; but after certain PA threshold, TEE plateaus. Then, a compensatory reduction in the expenditure of non-essential activities constrains the TEE. We hypothesized that high PA levels as locomotion associate with a compensatory attenuation in arm movements. We included 209 adults (64% females, mean [SD] age 32.1 [15.0] years) and 105 children (40% females, age 10.0 [1.1] years). Subjects wore, simultaneously, one accelerometer in the non-dominant wrist and another in the hip for >= 4 days. We analyzed the association between wrist-measured (arm movements plus locomotion) and hip-measured PA (locomotion). We also analyzed how the capacity to dissociate arm movements from locomotion influences total PA. In adults, the association between wrist-measured and hip-measured PA was better described by a quadratic than a linear model (Quadratic-R-2=0.54 vs. Linear-R-2=0.52; P=0.003). Above the 80th percentile of hip-measured PA, wrist-measured PA plateaued. In children, there was no evidence that a quadratic model fitted the association between wrist-measured and hip-measured PA better than a linear model (R-2=0.58 in both models, P=0.25). In adults and children, those with the highest capacity to dissociate arm movements from locomotion-i.e. higher arm movements for a given locomotion-reached the highest total PA. We conclude that, in adults, elevated locomotion associates with a compensatory reduction in arm movements (probably non-essential fidgeting) that partially explains the constrained TEE model. Subjects with the lowest arm compensation reach the highest total PA., Funding Agencies|Fondo Nacional de Desarrollo Cientifico y TecnologicoComision Nacional de Investigacion Cientifica y Tecnologica (CONICYT)CONICYT FONDECYT [11180361]; Spanish Ministry of Education, Culture and Sport [FPU15/04059, FPU15/02645, FPU14/04172]; University of Granada; Spanish Ministry of Economy and Competitiveness; Fondo de Investigacion Sanitaria del Instituto de Salud Carlos IIIInstituto de Salud Carlos III [PI13/01393]; Junta de Andalucia, Consejeria de Conocimiento, Investigacion y UniversidadesJunta de Andalucia; European Regional Development Funds (FEDER)European Commission [SOMM17/6107/UGR]; Redes Tematicas de Investigacion Cooperativa RETIC [Red SAMID RD16/0022]; EXERNET Research Network on Exercise and Health in Special Populations [DEP2005-00046/ACTI]; Fundacion Iberoamericana de Nutricion (ACTIBATE study); AstraZeneca HealthCare Foundation (ACTIBATE study); [PTA 12264-I]

Accelerometers accuracy for sedentary time (ST) and moderate-to-vigorous physical activity (MVPA) classification depends on accelerometer placement, data processing, activities, and sample characteristics. As intensities differ by age, this study sought to determine intensity cut-points at various wear locations people more than 70 years old. Data from 59 older adults were used for calibration and from 21 independent participants for cross-validation purposes. Participants wore accelerometers on their hip and wrists while performing activities and having their energy expenditure measured with portable calorimetry. ST and MVPA were defined as <= 1.5 metabolic equivalents (METs) and >= 3 METs (1 MET = 2.8 mL/kg/min), respectively. Receiver operator characteristic (ROC) analyses showed fair-to-good accuracy (area under the curve [AUC] = 0.62-0.89). ST cut-points were 7 mg (cross-validation: sensitivity = 0.88, specificity = 0.80) and 1 count/5 s (cross-validation: sensitivity = 0.91, specificity = 0.96) for the hip; 18 mg (cross-validation: sensitivity = 0.86, specificity = 0.86) and 102 counts/5 s (cross-validation: sensitivity = 0.91, specificity = 0.92) for the non-dominant wrist; and 22 mg and 175 counts/5 s (not cross-validated) for the dominant wrist. MVPA cut-points were 14 mg (cross-validation: sensitivity = 0.70, specificity = 0.99) and 54 count/5 s (cross-validation: sensitivity = 1.00, specificity = 0.96) for the hip; 60 mg (cross-validation: sensitivity = 0.83, specificity = 0.99) and 182 counts/5 s (cross-validation: sensitivity = 1.00, specificity = 0.89) for the non-dominant wrist; and 64 mg and 268 counts/5 s (not cross-validated) for the dominant wrist. These cut-points can classify ST and MVPA in older adults from hip- and wrist-worn accelerometers., Funding Agencies|University of Pittsburgh Claude D. Pepper Older Americans Independence Center, Research Registry and Developmental Pilot Grant [NIH P30 AG024827]; National Institute on Aging Professional Services [HHSN271201100605P]; Intramural Research Program of the National Institutes of Health, National Institute on AgingUnited States Department of Health & Human ServicesNational Institutes of Health (NIH) - USANIH National Institute on Aging (NIA); National Institutes of HealthUnited States Department of Health & Human ServicesNational Institutes of Health (NIH) - USA [AG000181, AG036594]; Biomedical Research Networking Center on Frailty and Healthy Aging (CIBERFES); FEDER funds from the European UnionEuropean Commission [CB16/10/00477]; Spanish Ministry of Science and InnovationSpanish Government [FJC2018-037925-I]; Plan Propio de Investigacion 2020 from the University of Granada-Programa Contratos-Puente

The constrained total energy expenditure (TEE) model posits that progressive increases in physical activity (PA) lead to increases in TEE; but after certain PA threshold, TEE plateaus. Then, a compensatory reduction in the expenditure of non-essential activities constrains the TEE. We hypothesized that high PA levels as locomotion associate with a compensatory attenuation in arm movements. We included 209 adults (64% females, mean [SD] age 32.1 [15.0] years) and 105 children (40% females, age 10.0 [1.1] years). Subjects wore, simultaneously, one accelerometer in the non-dominant wrist and another in the hip for >= 4 days. We analyzed the association between wrist-measured (arm movements plus locomotion) and hip-measured PA (locomotion). We also analyzed how the capacity to dissociate arm movements from locomotion influences total PA. In adults, the association between wrist-measured and hip-measured PA was better described by a quadratic than a linear model (Quadratic-R-2=0.54 vs. Linear-R-2=0.52; P=0.003). Above the 80th percentile of hip-measured PA, wrist-measured PA plateaued. In children, there was no evidence that a quadratic model fitted the association between wrist-measured and hip-measured PA better than a linear model (R-2=0.58 in both models, P=0.25). In adults and children, those with the highest capacity to dissociate arm movements from locomotion-i.e. higher arm movements for a given locomotion-reached the highest total PA. We conclude that, in adults, elevated locomotion associates with a compensatory reduction in arm movements (probably non-essential fidgeting) that partially explains the constrained TEE model. Subjects with the lowest arm compensation reach the highest total PA., Funding Agencies|Fondo Nacional de Desarrollo Cientifico y TecnologicoComision Nacional de Investigacion Cientifica y Tecnologica (CONICYT)CONICYT FONDECYT [11180361]; Spanish Ministry of Education, Culture and Sport [FPU15/04059, FPU15/02645, FPU14/04172]; University of Granada; Spanish Ministry of Economy and Competitiveness; Fondo de Investigacion Sanitaria del Instituto de Salud Carlos IIIInstituto de Salud Carlos III [PI13/01393]; Junta de Andalucia, Consejeria de Conocimiento, Investigacion y UniversidadesJunta de Andalucia; European Regional Development Funds (FEDER)European Commission [SOMM17/6107/UGR]; Redes Tematicas de Investigacion Cooperativa RETIC [Red SAMID RD16/0022]; EXERNET Research Network on Exercise and Health in Special Populations [DEP2005-00046/ACTI]; Fundacion Iberoamericana de Nutricion (ACTIBATE study); AstraZeneca HealthCare Foundation (ACTIBATE study); [PTA 12264-I]

Accelerometers accuracy for sedentary time (ST) and moderate-to-vigorous physical activity (MVPA) classification depends on accelerometer placement, data processing, activities, and sample characteristics. As intensities differ by age, this study sought to determine intensity cut-points at various wear locations people more than 70 years old. Data from 59 older adults were used for calibration and from 21 independent participants for cross-validation purposes. Participants wore accelerometers on their hip and wrists while performing activities and having their energy expenditure measured with portable calorimetry. ST and MVPA were defined as <= 1.5 metabolic equivalents (METs) and >= 3 METs (1 MET = 2.8 mL/kg/min), respectively. Receiver operator characteristic (ROC) analyses showed fair-to-good accuracy (area under the curve [AUC] = 0.62-0.89). ST cut-points were 7 mg (cross-validation: sensitivity = 0.88, specificity = 0.80) and 1 count/5 s (cross-validation: sensitivity = 0.91, specificity = 0.96) for the hip; 18 mg (cross-validation: sensitivity = 0.86, specificity = 0.86) and 102 counts/5 s (cross-validation: sensitivity = 0.91, specificity = 0.92) for the non-dominant wrist; and 22 mg and 175 counts/5 s (not cross-validated) for the dominant wrist. MVPA cut-points were 14 mg (cross-validation: sensitivity = 0.70, specificity = 0.99) and 54 count/5 s (cross-validation: sensitivity = 1.00, specificity = 0.96) for the hip; 60 mg (cross-validation: sensitivity = 0.83, specificity = 0.99) and 182 counts/5 s (cross-validation: sensitivity = 1.00, specificity = 0.89) for the non-dominant wrist; and 64 mg and 268 counts/5 s (not cross-validated) for the dominant wrist. These cut-points can classify ST and MVPA in older adults from hip- and wrist-worn accelerometers., Funding Agencies|University of Pittsburgh Claude D. Pepper Older Americans Independence Center, Research Registry and Developmental Pilot Grant [NIH P30 AG024827]; National Institute on Aging Professional Services [HHSN271201100605P]; Intramural Research Program of the National Institutes of Health, National Institute on AgingUnited States Department of Health & Human ServicesNational Institutes of Health (NIH) - USANIH National Institute on Aging (NIA); National Institutes of HealthUnited States Department of Health & Human ServicesNational Institutes of Health (NIH) - USA [AG000181, AG036594]; Biomedical Research Networking Center on Frailty and Healthy Aging (CIBERFES); FEDER funds from the European UnionEuropean Commission [CB16/10/00477]; Spanish Ministry of Science and InnovationSpanish Government [FJC2018-037925-I]; Plan Propio de Investigacion 2020 from the University of Granada-Programa Contratos-Puente

Objective This study aimed to describe the energy expenditure (EE) and macronutrient oxidation response to an individualized nonshivering cold exposure in young healthy adults. Methods Two different groups of 44 (study 1: 22.1 [SD 2.1] years old, 25.6 [SD 5.2] kg/m(2), 34% men) and 13 young healthy adults (study 2: 25.6 [SD 3.0] years old, 23.6 [SD 2.4] kg/m(2), 54% men) participated in this study. Resting metabolic rate (RMR) and macronutrient oxidation rates were measured by indirect calorimetry under fasting conditions in a warm environment (for 30 minutes) and in mild cold conditions (for 65 minutes, with the individual wearing a water-perfused cooling vest set at an individualized temperature adjusted to the individuals shivering threshold). Results In study 1, EE increased in the initial stage of cold exposure and remained stable for the whole cold exposure (P < 0.001). Mean cold-induced thermogenesis (9.56 +/- 7.9 kcal/h) was 13.9% +/- 11.6% of the RMR (range: -14.8% to 39.9% of the RMR). Carbohydrate oxidation decreased during the first 30 minutes of the cold exposure and later recovered up to the baseline values (P < 0.01) in parallel to opposite changes in fat oxidation (P < 0.01). Results were replicated in study 2. Conclusions A 1-hour mild cold exposure individually adjusted to elicit maximum nonshivering thermogenesis induces a very modest increase in EE and a shift of macronutrient oxidation that may underlie a shift in thermogenic tissue activity., Funding Agencies|Spanish Ministry of Economy and Competitiveness via the Fondo de Investigacion Sanitaria del Instituto de Salud Carlos III [PI13/01393, PTA 12264-I]; Retos de la Sociedad [DEP2016-79512-R]; European Regional Development Funds (ERDF)European Union (EU); Spanish Ministry of EducationSpanish Government [FPU13/04365, FPU14/04172, FPU15/04059]; Fundacion Iberoamericana de Nutricion; Redes Tematicas de Investigacion Cooperativa (RETIC, red de Salud Materno Infantil y del Desarrollo) [16/0022]; AstraZeneca HealthCare FoundationAstraZeneca; University of Granada Plan Propio de Investigacion 2016 excellence actions; Junta de Andalucia, Consejeria de Conocimiento, Investigacion y Universidades (ERDF) [SOMM17/6107/UGR]; Fundacion Alfonso Martin Escudero