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
Alannah K.A. McKay, Trent Stellingwerff, Ella S. Smith, David T. Martin, Iñigo Mujika, Vicky L. Goosey-Tolfrey, Jeremy Sheppard, and Louise M. Burke
Throughout the sport-science and sports-medicine literature, the term “elite” subjects might be one of the most overused and ill-defined terms. Currently, there is no common perspective or terminology to characterize the caliber and training status of an individual or cohort. This paper presents a 6-tiered Participant Classification Framework whereby all individuals across a spectrum of exercise backgrounds and athletic abilities can be classified. The Participant Classification Framework uses training volume and performance metrics to classify a participant to one of the following: Tier 0: Sedentary; Tier 1: Recreationally Active; Tier 2: Trained/Developmental; Tier 3: Highly Trained/National Level; Tier 4: Elite/International Level; or Tier 5: World Class. We suggest the Participant Classification Framework can be used to classify participants both prospectively (as part of study participant recruitment) and retrospectively (during systematic reviews and/or meta-analyses). Discussion around how the Participant Classification Framework can be tailored toward different sports, athletes, and/or events has occurred, and sport-specific examples provided. Additional nuances such as depth of sport participation, nationality differences, and gender parity within a sport are all discussed. Finally, chronological age with reference to the junior and masters athlete, as well as the Paralympic athlete, and their inclusion within the Participant Classification Framework has also been considered. It is our intention that this framework be widely implemented to systematically classify participants in research featuring exercise, sport, performance, health, and/or fitness outcomes going forward, providing the much-needed uniformity to classification practices.
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.
Petra Lundström, Katarina Lauruschkus, Åsa Andersson, and Åsa B. Tornberg
Purpose: To investigate the acute exercise effects of dynamic standing exercise on blood glucose and blood lactate among children and adolescents with cerebral palsy who are nonambulant. Methods: Twenty-four participants with cerebral palsy who are nonambulant performed 30 minutes of dynamic standing exercise using a motorized device enabling assisted passive movements in an upright weight-bearing position. Capillary blood samples were taken from the fingertip for measurement of blood glucose and blood lactate at rest and at the end of exercise. Results: At rest, the participants had hyperlactatemia that was unaffected after exercise, presented as median and interquartile range at rest 1.8 (1.3:2.7) mmol/L, and after exercise 2.0 (1.1:2.5) mmol/L. Children and adolescents with Gross Motor Function Classification System, level V, had higher lactate levels at rest (2.5 [1.8:2.9] vs 1.4 [1.0:2.0]; P = .030) and after exercise (2.3 [2.0:2.6] vs 1.2 [0.9:2.2]; P = .032) compared with children and adolescents with Gross Motor Function Classification System, level IV, respectively. A statistically significant larger decrease in blood lactate levels after exercise was observed in children and adolescents with higher resting blood lactate levels (ρ = .56; P = .004). There were no statistically significant changes in blood glucose. Conclusions: Forty percentage of the participants had mild hyperlactatemia at rest and participants with the highest blood lactate levels at rest had the greatest decrease in blood lactate levels after one bout of exercise. Children and adolescents who were classified with the highest level of the Gross Motor Function Classification Scale had higher blood lactate levels. More studies are needed on how to prevent chronically high resting levels of lactate with exercise in children with cerebral palsy who are nonambulant.
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.