The Evolution of

Accelerometers and the

Future Role of Self-Reported

Physical Activity

Richard Troiano, Ph.D.

Wherefore Today?

• Overview of accelerometers and use

• Benefits of device measures

• Comparing devices and questionnaires

HOW ACCELEROMETERS

WORK

Accelerometer Methods

• Measures body movement in terms of

acceleration

– Related to intensity of physical activity

– Measured in 1 to 3 orthogonal planes

• anterior-posterior

• medial-lateral

• vertical

– “Moment-by-moment” (100 Hz – 1 minute)

– Data stored for later download/analysis

– Proprietary filtering and processing for “counts”

– Need intensity thresholds from calibration studies OR

– Algorithms to classify raw data

ACCELEROMETER USE

Accelerometer Cites in Scopus 2000-2015

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2012

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2015

Art

icle

s

Year

Trend in Accelerometer Articles

“physical activity” OR exercise AND acceleromet*

National Surveillance with Devices

• National Health and Nutrition Survey of Japan

(pedometers) (annually since 1989)

• US National Health and Nutrition Examination

Survey (NHANES) 2003-2006, 2011-2014

• Canadian Health Measures Surveys (2007-11)

• Health Survey for England 2008

• Australian National Nutrition and Physical

Activity Survey (NNPAS) 2011-2012

(pedometers)

• Finnish Health 2012

Large Cohorts with Devices

• Activity and Function of the Elderly in Ulm (ActiFE Ulm)

• Avon Longitudinal Study of Parents and Children (ALSPAC)

• Child Heart and Health Study in England (CHASE)

• European Youth Heart Study (EYHS)

• Identification and Prevention of Dietary- and Lifestyle-Induced

Health Effects in Children and Infants (IDEFICS)

• International Study of Childhood Obesity, Lifestyle and the

Environment (ISCOLE)

• Millennium Cohort Study

• Personal and Environmental Associations with Children’s Health

(PEACH)

• Raine Study

• Sport Physical Activity & Eating Behaviour: Environmental

Determinants in Young People (SPEEDY)

• UK Biobank

• Women’s Health Study

Why?

ACCELEROMETER

BENEFITS

Stronger Biomarker Associations

Biomarker Self-report Accelerometer

Beta (SE) Adj. Wald F Beta (SE) Adj. Wald F

SBP 0.01 (0.03) 0.23 -0.43 (0.14) 8.89**

BMI -0.04 (0.01) 14.95*** -0.77 (0.08) 86.71****

HDL (mg/dL) 0.10 (0.03) 8.54** 1.41 (0.27) 27.77****

Glycohemoglobin -0.004 (0.001) 7.91** -0.05 (0.01) 47.11****

Glucose 0.01 (0.07) 0.06 -1.67 (0.30) 30.77****

Insulin (μU/mL) -0.08 (0.03) 10.15** -1.11 (0.12) 81.53****

Atienza et al., 2011 MSSE

Minutes in bouts, Beta per 10 min unit

** p < 0.01

*** p < 0.001

**** p < 0.0001

Precise Time Resolution

– NHANES 2003-2006

– Ages 6-19 y

– Cardiometabolic risk score:

• Waist circumference

• Non-HDL cholesterol

• C-reactive protein

• Systolic blood pressure

Published: October 5, 2011

Sporadic vs. Bouts of MVPA

5-min bouts 10-min bouts

* BRFSS 2005 (30 min x 5d moderate or 20 min x 3 d vigorous)

** NHANES 2003-2004 (150 min/week moderate or greater intensity)

*** NHANES 2003-2004, 20-59 y (30 min x 5d moderate or greater, Troiano et al. 2008)

49.9

3.8

57.8

46.4

3.2

42.5

0

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BRFSS Self-Report* NHANES Self-Report** Accelerometer***

% m

eeti

ng

reco

mm

en

dati

on Men Women

U.S. Adults Meeting PA Recommendations

HOW I USED TO THINK ABOUT

THESE RESULTS

Skeptic’s View of Self-Report

16

Dr. Gregory

House, M.D.

Everybody lies.

I’ve found when you want to know the truth

about someone, that someone is probably

the last person you should ask.

Shall We Play Football?

The Football Example

• Time

• Position

• Movement

Thanks to Heather Bowles

Physical Activity Conceptual Framework

Pettee Gabriel et al., 2012 JPAH

Related, but not quantitatively identical

Measures: Self-Report vs. Devices

• Physical activity ≠ physical activity

– Even if you express it as MET minutes

• Participants report behaviors

– Perceptions

– Context

• Devices (primarily) measure motion

• Each approach has value, but the measure

must match the purpose & combo may be best

• Measurement of Active and Sedentary

Behaviors: Closing the Gaps in Self-Report

Methods

– Supplement to JPAH January 2012

Similar Concerns for Sedentary

• TV-watching

• Screen-time (TV, video, various computer)

• Total reported sitting

• Actigraph counts <100, <150

• Postural measures

Which is Better?

Barolo Brunello

“Not better, just different”

Thank you