Introduction: Accelerometer-based measurements of physical activity types are commonly used to replace self-reports. To advance the field, it is desirable that such measurements allow accurate detection of key daily physical activity types. This study aimed to evaluate the performance of a machine learning classifier for detecting sitting, standing, lying, walking, running, and cycling based on a dual versus single accelerometer setups during free-living. Methods: Twenty-two adults (mean age [SD, range] 38.7 [14.4, 25–68] years) were wearing two Axivity AX3 accelerometers positioned on the low back and thigh along with a GoPro camera positioned on the chest to record lower body movements during free-living. The labeled videos were used as ground truth for training an eXtreme Gradient Boosting classifier using window lengths of 1, 3, and 5 s. Performance of the classifier was evaluated using leave-one-out cross-validation. Results: Total recording time was ∼38 hr. Based on 5-s windowing, the overall accuracy was 96% for the dual accelerometer setup and 93% and 84% for the single thigh and back accelerometer setups, respectively. The decreased accuracy for the single accelerometer setup was due to a poor precision in detecting lying based on the thigh accelerometer recording (77%) and standing based on the back accelerometer recording (64%). Conclusion: Key daily physical activity types can be accurately detected during free-living based on dual accelerometer recording, using an eXtreme Gradient Boosting classifier. The overall accuracy decreases marginally when predictions are based on single thigh accelerometer recording, but detection of lying is poor.
Kerstin Bach, Atle Kongsvold, Hilde Bårdstu, Ellen Marie Bardal, Håkon S. Kjærnli, Sverre Herland, Aleksej Logacjov, and Paul Jarle Mork
Logan T. Markwell, Andrew J. Strick, and Jared M. Porter
Sports, along with nearly all facets of life, have been impacted by the COVID-19 pandemic. The National Basketball Association quickly adopted a unique method to finish the 2019–2020 regular season and playoffs. The entire league quarantined for months in what was known as the “NBA bubble” where games were played in spectator-less arenas. During this time, increases in shooting accuracy were reported, suggesting that free throws and field goals were made at record-breaking levels. This study examined differences in free throw shooting accuracy with and without spectators. Archival data were retrieved and analyzed to evaluate the potential differences. Free throw shooting accuracy with and without spectators were examined in multiple analyses. Our examination revealed free throw percentages were significantly greater in spectator-less arenas compared with the 2018 and 2019 seasons with spectators. Changes of the environmental characteristics, due to spectator-less arenas, were likely contributors to the improved free throw phenomenon reported in this study.
Alexandra Stribing, Adam Pennell, Emily N. Gilbert, Lauren J. Lieberman, and Ali Brian
Individuals with visual impairments (VI) trend toward lower motor competence when compared with peers without VI. Various forms of perception often affects motor competence. Thus, it is important to explore factors that influence forms of perception and their differential effects on motor competence for those with VI. Therefore, the purposes of this study were to explore and describe the differential effects of age, gender, and degree of vision on self-perceptions, parents’ perceptions, metaperceptions, and locomotor skills, and to examine potential associations among all variables with actual locomotor competence for adolescents with VI. Adolescents with VI completed two questionnaires and the Test of Gross Motor Development-Third Edition. Parents completed a parent perception questionnaire. Mann–Whitney U and Kruskal–Wallis H analyses showed no differential effects for gender or age on any dependent measures. Degree of vision affected locomotor skills, but not any other factor. Spearman rho correlations showed significant associations among locomotor and self-perceptions, degree of vision and locomotor, and metaperceptions with parents’ perceptions. Adolescents reported relatively high self-perceptions and metaperceptions; however, their actual locomotor competence and parents’ perceptions were relatively low. Findings may help situate future intervention strategies targeting parents supporting their children’s locomotor skills through self-perceptions.
Jennifer L. Gay and David M. Buchner
Introduction: Little is known about the stability of occupational physical activity (PA) and documented compensation effects over time. Study objectives were to (a) determine the stability of accelerometer estimates of occupational and nonoccupational PA over 6 months and 1 year in adults who do not change jobs, (b) examine PA stability in office workers relative to employees with nonoffice jobs who may be more susceptible to seasonal perturbations in work tasks, and (c) examine the stability data for compensation effects seen at baseline in this sample. Methods: City/county government workers from a variety of labor sectors wore an accelerometer at initial data collection, and at 6 (n = 98) and 12 months (n = 38) following initial data collection. Intraclass correlation coefficients (ICCs) were calculated for accelerometer counts and minutes by intensity, domain, and office worker status. Partial correlation coefficients were examined for compensation effects. Results: ICCs ranged from .19 to .91 for occupational and nonwork activity variables. ICCs were similar by office worker status. In both counts and minutes, greater occupational PA correlated with lower total nonwork PA. However, as minutes of occupational moderate to vigorous physical activity increased, nonoccupational moderate to vigorous physical activity did not decrease. Conclusions: There was moderate to high stability in occupational and nonoccupational PA over 6- and 12-month data collection. Occupational PA stability was greater in nonoffice workers, suggesting that those employees’ PA may be less prone to potential cyclical factors at the workplace. Confirmation of the compensation effect further supports the need for workplace intervention studies to examine changes in all intensities of activity during and outside of work time.
Paul Bernard Rukavina
The deleterious effects of weight bias in physical activity spaces for children, adolescents, and adults are well documented. Different types of weight bias occur, and they interact at multiple levels within a person’s ecology, from the messaging of often unattainable sociocultural thin/muscular ideals and physical inequities (e.g., equipment not appropriate for body shapes and sizes) to interpersonal and public discriminatory comments. However, the most damaging is the internalization and application of negative weight-bias stereotypes by those with overweight and obesity to themselves. An imperative for social justice is now; there is great need to advocate for, provide support for, and design inclusive physical activity spaces to reduce weight bias so that all individuals feel welcome, accept their bodies, and are empowered to live a healthy, active lifestyle. To make this a reality, an interdisciplinary and preventive approach is needed to understand bias and how to minimize it in our spaces.
Robert A.J. Walker and Kazuhiro Harada
Japan has become a super-aged society. To overcome the negative implications of this, practitioners are increasingly using exercise-based interventions to reduce the requirement for long-term care among Japanese older adults. However, no comprehensive means of assessing the wide range of exercise behavioral determinants exists for this population. Thus, the principle aim of this study was to develop a questionnaire based upon the theoretical domains framework—a framework that has synthesized a wide range of behavior change theories. Completed responses were received from 1,000 Japanese older adults who resided in the Kansai area of Japan. Findings were suggestive of good reliability and validity for seven unique psychological determinants of exercise. This study was the first to provide a measurement tool related to a distinct range of psychological determinants of exercise among Japanese older adults.
Scott Kretchmar and Mark L. Latash
In this essay, we adopt a theory of behavior developed by the French philosopher Maurice Merleau-Ponty in an attempt to find common ground between philosophy and physics. We look for ways to reconcile matter with meaning, physical motion with the principles of ethics, body with mind. We proceed in three steps, first by providing a review of Merleau-Ponty’s theory; second by showing how ethical behavior is constrained and shaped by factors found in physics, chemistry, and biology; and, finally, by describing how physical motion is affected by factors that transcend the laws of classical physics. For the latter purpose, we accept a theory of parametric control of movements with spatial referent coordinates. Our purpose is not to solve specific problems of motor control or moral decision making but, rather, to test a general theoretical scheme that carries a number of practical implications for both research and education, including the need for collaboration between and among diverse research subdisciplines in kinesiology.