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
Arto J. Pesola, Timo Rantalainen, Ying Gao, and Taija Finni
Objective: Habitual walking is important for health and can be measured with accelerometry, but accelerometry does not measure physiological effort relative to capacity. We compared accelerometer-measured absolute intensity and electromyography (EMG)-measured relative muscle activity between people with low versus excellent aerobic fitness levels during their habitual walking. Methods: Forty volunteers (19 women; age 49.3 ± 17.1 years, body mass index 24.0 ± 2.6 kg/m2; peak oxygen uptake 40.3 ± 12.5 ml/kg/min) wore EMG-shorts and a hip-worn accelerometer simultaneously for 11.6 ± 2.2 hr on 1.7 ± 1.1 days. Continuous gait bouts of at least 5-min duration were identified based on acceleration mean amplitude deviation (MAD, in milli gravitational acceleration, mg) and mean EMG amplitude, with EMG normalized to maximal isometric knee extension and flexion (EMG, in percentage of maximal voluntary contraction EMG). Peak oxygen uptake was measured on a treadmill and maximal strength in isometric leg press (leg press max). MAD and EMG were compared between age- and sex-specific fitness groups (low-average, good, and excellent) and in linear models. Results: During habitual walking bouts (4.1 ± 4.1 bouts/day, 0.9 ± 1.0 min/bout), the low-average fit participants had an approximately 28% lower MAD (245 ± 64.3 mg) compared with both good fit and excellent fit participants (313 ± 68.1 mg, p < .05), but EMG was the same (13.1% ± 8.42% maximal voluntary contraction EMG, p = .10). Absolute, relative to body mass, and relative to skeletal muscle mass peak oxygen uptake (but not leg press max) was positively associated with MAD independent of age and sex (p < .01), but there were no associations with EMG. Conclusions: People with low-average aerobic capacity habitually walk with a lower accelerometer-measured absolute intensity, but the physiological stimulus for lower-extremity muscles is similar to those with excellent aerobic capacity. This should be considered when measuring and prescribing walking for health.
Lewis King, SarahJane Cullen, Jean McArdle, Adrian McGoldrick, Jennifer Pugh, Giles Warrington, and Ciara Losty
A large proportion of jockeys report symptoms associated with mental health difficulties (MHDs), yet most do not seek help from professional mental health support services. Due to the paucity of literature in this field, this study sought to explore jockeys’ barriers to, and facilitators of, help-seeking for MHDs. Twelve jockeys participated in semistructured interviews, subsequently analyzed via reflexive thematic analysis. Barriers to help-seeking included the negative perceptions of others (stigma and career implications), cultural norms (masculinity and self-reliance), and low mental health literacy (not knowing where to seek help, minimization of MHDs, negative perceptions of treatment, and recognizing symptoms). Facilitators to help-seeking included education (exposure to psychological support at a younger age), social support (from professionals, jockeys, family, and friends), and media campaigns (high-profile disclosures from jockeys). Findings are consistent with barrier and facilitator studies among general and athletic populations. Applied recommendations and future research considerations are presented throughout the manuscript.
Jemima C. John, Natalia I. Heredia, Lorna H. McNeill, Deanna M. Hoelscher, Sue Schembre, MinJae Lee, Jasmine J. Opusunju, Margaret Goetz, Maria Aguirre, Belinda M. Reininger, and Larkin L. Strong
Background: Limited information exists on how the family unit aids or impedes physical activity (PA) engagement within Hispanic populations. This qualitative study explored family-level influences on PA in dyads of adult Hispanic family members (eg, parent–adult child, siblings, spouses). Methods: In-person interviews and brief surveys were conducted together with 20 dyads lasting 1.5 hours each. Two researchers coded and analyzed text using thematic analysis in NVivo (version 11.0). They resolved discrepancies through consensus and used matrix coding analysis to examine themes by participants’ demographics. Results: The participants were mainly women (70%), from Mexico (61.5%), and they reported low levels of acculturation (87.5%). Themed facilitators for PA included “verbal encouragement,” “help with responsibilities,” “exercising with someone,” and “exercising to appease children.” Themed challenges included “lack of support,” “challenges posed by children,” “sedentary behaviors,” and “competing responsibilities.” Women more so than men described family-level challenges and facilitators, and dyads where both study partners were physically active provided more positive partner interaction descriptions for PA support than other dyads. Conclusions: This study suggests that leveraging family support may be an important approach to promote and sustain PA, and that family-focused interventions should integrate communication-building strategies to facilitate family members’ ability to solicit support from each other.
Alanna Weisberg, Hyun Suk Lee, Tak Fung, and Larry Katz
The overhand throw is a complex whole-body motor skill that is fundamental to many sports and activities. When throwing properly, the momentum generated to complete the movement begins in the lower body and transfers through the trunk to the throwing arm. This proof-of-concept study’s primary purpose was to evaluate the impact of the nonthrowing arm on the ball speed during an overhand throw with both the dominant and nondominant arms. Eighteen participants (age: 20.20 ± 2.90 years, nine women) were divided into two intervention groups: a pulling group taught to engage the nonthrowing arm through a pull toward the body and a nonpulling group taught the overhand throw using a component-based physical education curriculum. Each participant completed 12 total throws, six for each side (dominant and nondominant arm). Ball speed and kinematic data were collected using an eight-camera motion analysis system and were assessed using a pre–post study design. The two groups showed significant improvements pre–post when throwing with both the dominant and nondominant arms. Based on effect size comparisons, engaging the nonthrowing arm makes a meaningful difference in maximal ball velocity.
Bradley J. Cardinal
Kinesiology is a field focused on physical activity and its impact on health, society, and quality of life. But do all people have equal opportunities to access and experience physical activity? Do physical activity settings allow people to freely express themselves? Are the benefits of physical activity universally shared by all people? If the answer to any of these questions is “no,” then these questions demand not only our immediate attention, but also our collective action. During the National Academy of Kinesiology’s 90th anniversary meeting, September 22–24, 2021, these questions and others were explored through presentations devoted to the theme “Kinesiology’s Social Justice Imperative.” This essay overviews the meeting, its purpose, and the organizers and introduces the 11 thematic papers in the “Proceedings of the National Academy of Kinesiology’s 2021 Meeting: Kinesiology’s Social Justice Imperative” issue, plus a 12th essay commemorating the National Academy of Kinesiology’s 90th anniversary meeting.
Wojtek Chodzko-Zajko, Debra J. Rose, Diane E. Whaley, Philip D. Chilibeck, and Samuel R. Nyman
Areekul Amornsriwatanakul, Narongsak Noosorn, Kittipong Poonchob, Rung Wongwat, Somkiat Sornprasit, Phataraphon Markmee, Michael Rosenberg, and Karen Milton
Background: This study aimed to determine current practice in physical activity (PA) promotion in Thai schools, explore barriers and facilitators to PA promotion within the school setting, and identify strategies to support schools’ future practice. Methods: A qualitative study design was applied comprising document analysis, focus groups, in-depth interviews, and onsite observations. The focus groups and in-depth interviews were conducted with 144 informants, purposively recruited through 24 schools in 4 regions across Thailand. Inductive content analysis was used. Results: Most schools were promoting PA in the absence of written policies, and without an accurate understanding of PA. Nonalignment of school performance indicators and policies, concerns about children’s academic performance, and lack of budget were raised as barriers to PA promotion, whereas strong partnerships with multiple local stakeholders facilitated school-based PA promotion. Mandated government PA policies and more information support were suggested as strategies to enhance schools’ future practices. Conclusions: For PA promotion to be successful in the school setting, significant challenges will need to be addressed. Results from this study help the government and concerned stakeholders to better understand the situation at the school level, and further strive for achieving the target PA levels specified in the National PA Plan.
Konstantinos D. Tambalis, Stamatis Mourtakos, and Labros S. Sidossis
Background: The purpose was to examine the potential associations of birth weight and infant growth with physical fitness (PF) components in childhood. Method: A random sample of 5125 dyads of children aged 8–9 years and their mothers were evaluated. Telephone interviews were carried out with the use of a standardized questionnaire for the collection of maternal lifestyle factors. Mothers were asked to provide information contained in their medical booklets and pregnancy ultrasound records. Data from 5 PF tests were used to assess cardiorespiratory fitness, speed, and body strength. Linear regression analysis was applied to assess the associations between birth weight and infant growth with PF test performances and logistic regression analysis to evaluate the associations of normal weight versus low birth weight and normal versus accelerated infant growth with PF tests performance categories (low vs high/average). Results: Birth weight was favorably associated with cardiorespiratory fitness (b = 0.12 stage increase per SD increase in birth weight, P = .047), lower body strength (b = 1.07, P = .037), upper body strength (b = 0.10, P = .038), and speed (b = −0.04, P = .001), and infant growth was associated with upper body strength (b = 0.21 cm increase per SD increase in infant weight gain, P < .001) after adjusting for children’s body mass index and several perinatal factors. Low birth weight children had 35% increased odds for low performances in PF tests compared with their normal birth weight counterparts. Conclusion: Low birth weight negatively affects childhood PF, and hence, it could play an unfavorable role in the future health of the offspring.