scholarly journals Absolute Accelerometer-Based Intensity Prescription Compared to Physiological Variables in Pregnant and Nonpregnant Women

2020 ◽  
Vol 17 (16) ◽  
pp. 5651
Author(s):  
Philipp Birnbaumer ◽  
Pavel Dietz ◽  
Estelle Dorothy Watson ◽  
Gudani Mukoma ◽  
Alexander Müller ◽  
...  
Keyword(s):  
Ventilatory Threshold ◽  
Resting Metabolic Rate ◽  
Moderate Intensity ◽  
Cut Points ◽  
Physiological Variables ◽  
Metabolic Equivalents ◽  
Ventilatory Equivalent ◽  
Ventilatory Parameters ◽  
Accelerometer Cut Points ◽  
The Relationship

Estimation of the intensity of physical activity (PA) based on absolute accelerometer cut points (Cp) likely over- or underestimates intensity for a specific individual. The purpose of this study was to investigate the relationship between absolute moderate intensity Cp and the first ventilatory threshold (VT1). A group of 24 pregnant and 15 nonpregnant women who performed a submaximal incremental walking test with measures of ventilatory parameters and accelerations from three different accelerometers on the wrist (ActiGraph wGT3X-BT, GENEActiv, Axivity AX3) and one on the hip (Actigraph wGT3X-BT) were analyzed. Cp were determined corresponding to 3 metabolic equivalents of task (MET), using the conventional MET definition (Cp3.5) (3.5 mL/kg×min) and individual resting metabolic rate (Cpind). The ventilatory equivalent (VE/VO2) was used to determine VT1. Accelerations at VT1 were significantly higher (p < 0.01) compared to Cp3.5 and Cpind in both groups. Cp3.5 and Cpind were significantly different in nonpregnant (p < 0.01) but not in pregnant women. Walking speed at VT1 (5.7 ± 0.5/6.2 ± 0.8 km/h) was significantly lower (p < 0.01) in pregnant compared to nonpregnant women and correspondent to 3.8 ± 0.7/4.9 ± 1.4 conventional METs. Intensity at absolute Cp was lower compared to the intensity at VT1 independent of the device or placement in pregnant and nonpregnant women. Therefore, we recommend individually tailored cut points such as the VT1 to better assess the effect of the intensity of PA.

Mechanistic basis for the gas exchange threshold in Thoroughbred horses

2002 ◽  
Vol 92 (4) ◽  
pp. 1499-1505 ◽  
Author(s):  
Paul McDonough ◽  
Casey A. Kindig ◽  
Howard H. Erickson ◽  
David C. Poole
Keyword(s):  
Gas Exchange ◽  
Ventilatory Threshold ◽  
Healthy Humans ◽  
Thoroughbred Horses ◽  
Ventilatory Equivalent ◽  
Mechanistic Basis ◽  
Cardiopulmonary Performance ◽  
The Relationship ◽  
Peak Blood ◽  
Gas Exchange Threshold

The exercising Thoroughbred horse (TB) is capable of exceptional cardiopulmonary performance. However, because the ventilatory equivalent for O2(V˙e/V˙o 2) does not increase above the gas exchange threshold (Tge), hypercapnia and hypoxemia accompany intense exercise in the TB compared with humans, in whom V˙e/V˙o 2 increases during supra-Tge work, which both removes the CO2 produced by the HCO[Formula: see text] buffering of lactic acid and prevents arterial partial pressure of CO2 (PaCO2 ) from rising. We used breath-by-breath techniques to analyze the relationship between CO2 output (V˙co 2) andV˙o 2 [V-slope lactate threshold (LT) estimation] during an incremental test to fatigue (7 to ∼15 m/s; 1 m · s−1 · min−1) in six TB. Peak blood lactate increased to 29.2 ± 1.9 mM/l. However, as neither V˙e/V˙o 2 norV˙e/V˙co 2 increased, PaCO2 increased to 56.6 ± 2.3 Torr at peakV˙o 2(V˙o 2 max). Despite the presence of a relative hypoventilation (i.e., no increase inV˙e/V˙o 2 orV˙e/V˙co 2), a distinct Tge was evidenced at 62.6 ± 2.7%V˙o 2 max. Tge occurred at a significantly higher ( P < 0.05) percentage ofV˙o 2 max than the lactate (45.1 ± 5.0%) or pH (47.4 ± 6.6%) but not the bicarbonate (65.3 ± 6.6%) threshold. In addition, PaCO2 was elevated significantly only at a workload > Tge. Thus, in marked contrast to healthy humans, pronounced V-slope (↑V˙co 2/V˙o 2) behavior occurs in TB concomitant with elevated PaCO2 and without evidence of a ventilatory threshold.

scholarly journals Calibration and Cross-Validation of Accelerometery for Estimating Movement Skills in Children Aged 8–12 Years

Sensors ◽  
2020 ◽  
Vol 20 (10) ◽  
pp. 2776 ◽  
Author(s):  
Michael J. Duncan ◽  
Alexandra Dobell ◽  
Mark Noon ◽  
Cain C. T. Clark ◽  
Clare M. P. Roscoe ◽  
...  
Keyword(s):  
Sedentary Behaviour ◽  
Motor Skills ◽  
Cross Validation ◽  
Moderate Intensity ◽  
Roc Curve Analysis ◽  
Independent Dataset ◽  
Object Control ◽  
Cut Points ◽  
Accelerometer Cut Points ◽  
Children’S Physical Activity

(1) Background: This study sought to calibrate triaxial accelerometery, worn on both wrists, waist and both ankles, during children’s physical activity (PA), with particular attention to object control motor skills performed at a fast and slow cadence, and to cross-validate the accelerometer cut-points derived from the calibration using an independent dataset. (2) Methods: Twenty boys (10.1 ±1.5 years) undertook seven, five-minute bouts of activity lying supine, standing, running (4.5kmph−1) instep passing a football (fast and slow cadence), dribbling a football (fast and slow cadence), whilst wearing five GENEActiv accelerometers on their non-dominant and dominant wrists and ankles and waist. VO2 was assessed concurrently using indirect calorimetry. ROC curve analysis was used to generate cut-points representing sedentary, light and moderate PA. The cut-points were then cross-validated using independent data from 30 children (9.4 ± 1.4 years), who had undertaken similar activities whilst wearing accelerometers and being assessed for VO2. (3) Results: GENEActiv monitors were able to discriminate sedentary activity to an excellent level irrespective of wear location. For moderate PA, discrimination of activity was considered good for monitors placed on the dominant wrist, waist, non-dominant and dominant ankles but fair for the non-dominant wrist. Applying the cut-points to the cross-validation sample indicated that cut-points validated in the calibration were able to successfully discriminate sedentary behaviour and moderate PA to an excellent standard and light PA to a fair standard. (4) Conclusions: Cut-points derived from this calibration demonstrate an excellent ability to discriminate children’s sedentary behaviour and moderate intensity PA comprising motor skill activity.

A Steps/Minute Value for Moderate Intensity Physical Activity in Adolescent Females

2012 ◽  
Vol 24 (3) ◽  
pp. 399-408 ◽  
Author(s):  
Deirdre M. Harrington ◽  
Kieran P. Dowd ◽  
Catrine Tudor-Locke ◽  
Alan E. Donnelly
Keyword(s):  
Physical Activity ◽  
Mixed Model ◽  
Adolescent Females ◽  
Moderate Intensity ◽  
Moderate Intensity Physical Activity ◽  
Metabolic Equivalents ◽  
Intensity Physical Activity ◽  
Analytical Approaches ◽  
The Relationship ◽  
Over Ground Walking

The number of steps/minute (i.e., cadence) that equates to moderate intensity in adolescents is not known. To that end, 31 adolescent females walked on a treadmill at 5 different speeds while wearing an ActivPAL accelerometer and oxygen uptake was recorded by indirect calorimetry. The relationship between metabolic equivalents (METs) and cadence was explored using 3 different analytical approaches. Cadence was a significant predictor of METs (r=.70; p<.001). Moderate intensity (3 METs) corresponded to 94 or 114 steps/minute based on the mixed model and ROC analysis, respectively. These two values, and a practical value of 100 steps/minute, were cross-validated on an independent sample of 33 adolescent females during over-ground walking at 3 speeds. The sensitivity and specificity of each value correctly identifying 3 METs were 98.5% and 87.2% for 94 steps/minute, 72.9% and 98.8 for 114 steps/minute and 96.5% and 95.7% for 100 steps/minute. Compromising on a single cadence of 100 steps/minute would be a practical value that approximates moderate intensity in adolescent females and can be used for physical activity interpretation and promotion.

scholarly journals Investigation of the Relationship Between Peak Vertical Accelerations and Aerobic Exercise Intensity During Graded Walking and Running in Postmenopausal Women

2020 ◽  
pp. 1-9
Author(s):  
Erreka Gil-Rey ◽  
Kevin C. Deere ◽  
Sara Maldonado-Martín ◽  
Natalia Palacios-Samper ◽  
Agueda Azpeitia ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Aerobic Exercise ◽  
Exercise Intensity ◽  
Weight Bearing ◽  
Osteogenic Potential ◽  
Moderate Intensity ◽  
Metabolic Equivalents ◽  
Vertical Accelerations ◽  
Multilevel Linear Regression ◽  
The Relationship

How exercise intensity targets, calibrated according to oxygen consumption, relate to vertical impacts during weight-bearing exercise is currently unknown. The authors investigated the relationship between vertical peaks (VPs) and metabolic equivalents (METs) of oxygen consumption in 82 women during walking and running. The magnitude of VPs, measured using a hip-worn triaxial accelerometer, was derived from recommended aerobic exercise intensity targets. VPs were 0.63 ± 0.18g at the lower recommended absolute exercise intensity target (3 METs) but >1.5g at the upper end of moderate-intensity activities (1.90 ± 1.13g at 6 METs). Multilevel linear regression analyses identified speed and type of locomotion as the strongest independent predictors of VPs, explaining 54% and 11% of variance, respectively. The authors conclude that, in contrast to lower intensities, exercising close to or above the 6-MET threshold generates VPs of osteogenic potential, suggesting this could provide simultaneous benefits to decrease all-cause mortality and osteoporosis risk.

scholarly journals What is the Minimum Step Rate Required to Achieve Moderate-Intensity Walking Overground in Adolescent Girls?

2020 ◽  
Vol 32 (4) ◽  
pp. 197-203
Author(s):  
Mhairi J. MacDonald ◽  
Samantha G. Fawkner ◽  
Ailsa G. Niven
Keyword(s):  
Adolescent Girls ◽  
Mixed Model ◽  
Small Sample Size ◽  
Resting Metabolic Rate ◽  
Population Level ◽  
Small Sample ◽  
Moderate Intensity ◽  
Anthropometric Measures ◽  
Step Rate ◽  
Metabolic Equivalents

Background: In order to promote walking, researchers have sought to identify the required step rate to maintain a health-enhancing walking intensity However, there is limited evidence regarding the stepping rate required to promote moderate-intensity walking in adolescent girls. Purpose: To identify the step rate equivalent to moderate-intensity physical activity (MPA) in adolescent girls and to explore the influence that different anthropometric measures may have on the step rate equating to MPA in this population. Methods: A total of 56 adolescent girls (mean age = 13.8[0.7] y) were recruited to the study. Anthropometric variables and resting metabolic rate were assessed, followed by 3 overground walking trials on a flat surface at approximately 2, 3, and 4 mph, each lasting a minimum of 4 minutes. Oxygen uptake was assessed using a portable gas analyzer and subsequently converted into metabolic equivalents (METs). Step count was assessed by real-time direct observation hand tally. Results: Employing the linear regression between step rate and METs (r2 = .20, standard error of estimates = 0.003) suggests that 120 steps per minute was representative of an MPA (3 METs) equating to 7200 steps in 60 minutes. Multiple regression and mixed-model regression confirmed weight-related variables and maturity were significant predictors of METs (P < .01). Conclusion: The results suggest that, at population level, a step rate of 120 steps per minute may be advocated to achieve MPA in adolescent girls; although, due to the small sample size used, caution should be applied. At an individual level, other factors, such as age and weight, should be considered.

The Relationship of Actigraph Accelerometer Cut-Points for Estimating Physical Activity With Selected Health Outcomes

2012 ◽  
Vol 83 (3) ◽  
pp. 422-430 ◽  
Author(s):  
Paul D. Loprinzi ◽  
Hyo Lee ◽  
Bradley J. Cardinal ◽  
Carlos J. Crespo ◽  
Ross E. Andersen ◽  
...  
Keyword(s):  
Physical Activity ◽  
Health Outcomes ◽  
Cut Points ◽  
Actigraph Accelerometer ◽  
Relationship Of ◽  
Accelerometer Cut Points ◽  
The Relationship

scholarly journals Treadmill Calibration of the Actigraph GT1M in Young-to-Middle-Aged Obese-to-Severely Obese Subjects

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Eivind Aadland ◽  
Sigmund Alfred Anderssen
Keyword(s):  
Mixed Model ◽  
Linear Mixed Model ◽  
Operating Characteristics ◽  
Middle Aged ◽  
Cut Points ◽  
Metabolic Equivalents ◽  
Severely Obese ◽  
Obese Subjects ◽  
Accelerometer Cut Points ◽  
The Impact

To understand the impact of physical activity (PA) on health, valid accelerometer count cut points must be applied to measure PA. Because cut points may be population specific, we aimed to establish accelerometer cut points for moderate PA (MPA) and vigorous PA (VPA) (defined as ≥3 and ≥6 metabolic equivalents, resp.) in young-to-middle-aged obese-to-severely obese subjects. Data from 42 subjects (11 men; body mass index39.8±5.7; age43.2±9.2years) who performed a treadmill calibration using the Actigraph GT1M, were analyzed using ordinary linear regression (OLR), linear mixed model regression (MIX), and receiver operating characteristics curves (ROC 1; ROC 2). Cut points obtained from the models were quite different (612 to 1646 counts/min for MPA; 3061 to 7220 counts/min for VPA). We argue that the MIX approach, which resulted in cut points of 612 and 4980 counts/min for MPA and VPA, respectively, is the most appropriate method to establish accelerometer cut points in this setting. We conclude that accelerometer cut points are lower in young-to-middle-aged obese-to-severely obese subjects compared to young normal-weight subjects and that care should be taken when analyzing PA level in groups that vary in age and degree of obesity.

scholarly journals Calibration and Cross-Validation of Accelerometer Cut-Points to Classify Sedentary Time and Physical Activity from Hip and Non-Dominant and Dominant Wrists in Older Adults

Sensors ◽  
2021 ◽  
Vol 21 (10) ◽  
pp. 3326
Author(s):  
Jairo H. Migueles ◽  
Cristina Cadenas-Sanchez ◽  
Juan M. A. Alcantara ◽  
Javier Leal-Martín ◽  
Asier Mañas ◽  
...  
Keyword(s):  
Physical Activity ◽  
Older Adults ◽  
Cross Validation ◽  
Sedentary Time ◽  
Vigorous Physical Activity ◽  
Area Under The Curve ◽  
Cut Points ◽  
Metabolic Equivalents ◽  
Sample Characteristics ◽  
Accelerometer Cut Points

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.

Ventilatory threshold is related to walking tolerance in patients with intermittent claudication

VASA ◽  
2012 ◽  
Vol 41 (4) ◽  
pp. 275-281 ◽  
Author(s):  
da Rocha Chehuen ◽  
G. Cucato ◽  
P. dos Anjos Souza Barbosa ◽  
A. R. Costa ◽  
M. Ritti-Dias ◽  
...  
Keyword(s):  
Blood Flow ◽  
Oxygen Uptake ◽  
Intermittent Claudication ◽  
Lower Limb ◽  
Ventilatory Threshold ◽  
Reactive Hyperemia ◽  
Ankle Brachial Index ◽  
Metabolic Parameters ◽  
Walking Distance ◽  
The Relationship

Background: This study assessed the relationship between lower limb hemodynamics and metabolic parameters with walking tolerance in patients with intermittent claudication (IC). Patients and methods: Resting ankle-brachial index (ABI), baseline blood flow (BF), BF response to reactive hyperemia (BFRH), oxygen uptake (VO2), initial claudication distance (ICD) and total walking distance (TWD) were measured in 28 IC patients. Pearson and Spearman correlations were calculated. Results: ABI, baseline BF and BF response to RH did not correlate with ICD or TWD. VO2 at first ventilatory threshold and VO2peak were significantly and positively correlated with ICD (r = 0.41 and 0.54, respectively) and TWD (r = 0.65 and 0.71, respectively). Conclusions: VO2peak and VO2 at first ventilatory threshold, but not ABI, baseline BF and BFHR were associated with walking tolerance in IC patients. These results suggest that VO2 at first ventilatory threshold may be useful to evaluate walking tolerance and improvements in IC patients.

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