7. Project Summary/Abstract
Physical activity (PA) is associated with a number of short- and long-term health outcomes in children,
adolescents, and young adults (collectively, young people). In particular, an inverse dose-response relationship
exists between moderate-to-vigorous PA (MVPA) and cardio-metabolic risk factors. Accurately quantifying
young people’s daily MVPA is essential for effective surveillance, research, clinical, and public health
applications. Yet, technical expressions of intensity in terms of energy expenditure (i.e., oxygen consumption
or metabolic cost expressed in metabolic equivalents or METs) and/or percent of age-predicted heart rate
maximum may be uninterpretable to all but those trained in human physiology. A more practically accessible
yet still objective metric is needed to track and influence young people’s healthful levels of PA.
The SKyRoCKeT Study (Surface-Knit and Reformulate CADENCE-Kids for Translation) will build on
the R21 CADENCE-Kids study and recruit a sex- and age-balanced sample of 360 young people 6-20 years of
age to: 1) Innovatively surface-‘knit’ the age dimension through a continuous, unbiased-by-age, and
physiologically-coherent age-cadence-log(MET) flexible surface approach without artificially-generated jumps
between age ranges and with enhanced precision of cadence-intensity threshold estimates. This single surface
will coherently transition between ages, borrow inter-age information, and be data-driven; 2) Reformulate
CADENCE-Kids by providing granular, age-specific cadence-intensity thresholds, calculated with enhanced
precision for MVPA. Data will be objectively collected using a similar treadmill protocol to the R21-funded pilot
study, with incrementally faster paces. A full running bout will now also be included for everyone when possible.
We will concurrently collect cadence with direct observation as well as with multiple contemporary wearable
technologies. Collecting cardio-respiratory fitness and habitual PA data, we will develop additional, innovative
algorithms to predict relative intensity defined by lab-based indicators of oxygen uptake (%VO2peak, %VO2R),
heart rate (%HRR, %HRmax), and rating of perceived exertion to facilitate computation of individually calibrated
thresholds applicable to the free-living or habitual PA living condition. We will also investigate additional
differences in surfaces and cadence-intensity thresholds by sex and body mass index standard deviation scores.
Height- and/or leg-length-specific (hyper)surfaces will be explored as more precise alternatives to the age
dimension; and 3) Propel science forward innovatively through translation to outdoor over-ground walking. We
hypothesize that treadmill-set cadence-intensity thresholds will reliably translate and allow eliciting predictable
metabolic costs during outdoor over-ground walking emblematic of free-living ambulatory behaviors.
The SKyRoCKeT Study is an innovative critical step to provide coherent, interpretable, objectively monitored
step-based intensity metrics of widespread use to inform national PA guidelines, interventions, assessments,
analyses, school-based health education curricula and programs, and public health messages for young people.