David S. Walsh and Paul M. Wright
Alison Griffin, Tim Roselli and Susan L. Clemens
Background: Health benefits of physical activity (PA) accrue with small increases in PA, with the greatest benefits for those transitioning from inactivity to any level of PA. This study examined whether self-reported PA time in Queensland adults changed between 2004 and 2018. Methods: The Queensland government conducts regular cross-sectional telephone surveys. Between 2004 and 2018, adults aged 18–75 years answered identical questions about their weekly minutes of walking, moderate PA, and vigorous PA. Hurdle regression estimated the average annual change in weekly minutes of PA overall and by activity type, focusing on sociodemographic differences in trends. Results: The sample size averaged 1764 (2004–2008) and 10,188 (2009–2018), totaling 107,171 participants aged 18–75 years. Unadjusted PA increased by 10 minutes per week per year (95% confidence interval [CI], 8.8–11.1) overall, with increases for most subgroups. Adjusted PA increased by 10.5 minutes per week per year (95% CI, 9.4–11.7). Trends differed by employment—employed adults and those not in the labor force increased by 14.3 (95% CI, 12.8–15.8) and 2.2 minutes per week per year (95% CI, 0.4–4.0), respectively, with no increase for unemployed adults. The increases were due to both an increased prevalence of doing any activity and an increased average duration among active adults. Conclusions: Since 2004, PA time has increased for Queensland adults, with substantial variability by employment status.
Paul M. Wright and David Walsh
Don Hellison (1938–2018) was a leader and trailblazer in sport and physical education pedagogy. Early in his career, he was an advocate for humanistic physical education. His engaged approach to scholarship culminated in the development of the Teaching Personal and Social Responsibility (TPSR) model, which is now recognized as a best practice for promoting social and emotional learning in physical education. The TPSR model has also been widely applied in the field of sport-based youth development. This is the introduction to the special issue devoted to Don’s life and legacy. It provides opening comments from the guest editors and a brief overview of the articles in the special issue.
Daniel C. McFarland, Alexander G. Brynildsen and Katherine R. Saul
Most upper-extremity musculoskeletal models represent the glenohumeral joint with an inherently stable ball-and-socket, but the physiological joint requires active muscle coordination for stability. The authors evaluated sensitivity of common predicted outcomes (instability, net glenohumeral reaction force, and rotator cuff activations) to different implementations of active stabilizing mechanisms (constraining net joint reaction direction and incorporating normalized surface electromyography [EMG]). Both EMG and reaction force constraints successfully reduced joint instability. For flexion, incorporating any normalized surface EMG data reduced predicted instability by 54.8%, whereas incorporating any force constraint reduced predicted instability by 43.1%. Other outcomes were sensitive to EMG constraints, but not to force constraints. For flexion, incorporating normalized surface EMG data increased predicted magnitudes of joint reaction force and rotator cuff activations by 28.7% and 88.4%, respectively. Force constraints had no influence on these predicted outcomes for all tasks evaluated. More restrictive EMG constraints also tended to overconstrain the model, making it challenging to accurately track input kinematics. Therefore, force constraints may be a more robust choice when representing stability.
Christopher J. Burcal, Sunghoon Chung, Madison L. Johnston and Adam B. Rosen
Background: Region-specific patient-reported outcomes (PROs) are commonly used in rehabilitation medicine. Digital versions of PROs may be implemented into electronic medical records and are also commonly used in research, but the validity of this method of administration (MOA) must be established. Purpose: To determine the agreement between and compare the test–retest reliability of a paper version (FAAM-P) and digital version (FAAM-D) of the Foot and Ankle Ability Measure (FAAM). Study Design: Randomized, nonblinded, crossover observational study. Methods: A total of 90 adults were randomized to complete the FAAM-P or FAAM-D first, and then completed the second MOA (first day [D1]). The FAAM-D was a digital adaptation of both FAAM-P subscales on Qualtrics. Identical test procedures were completed 1 week later (D2). Data were removed if a participant scored 100% on both MOA, reported injury between D1 and D2, or did not complete both MOA. Agreement was assessed on 46 participants between the 2 MOA using intraclass correlation coefficients (ICC) at D1. There was good-to-excellent test–retest reliability for the FAAM activities of daily living. Results: The authors observed good agreement between the FAAM-P and FAAM-D for the activities of daily living (ICC = .88) and sport scales (ICC = .87). Test–retest reliability was good-to-excellent for the FAAM activities of daily living (FAAM-P: ICC = .87; FAAM-D: ICC = .89) and sport (FAAM-P: ICC = .71; FAAM-D: ICC = .91). Conclusions: The MOA does not appear to affect the responses on the FAAM; however, the authors observed slightly higher reliability on the FAAM-D. The FAAM-D is sufficient to be used for generating practice-based evidence in rehabilitation medicine.
Jillian J. Haszard, Kim Meredith-Jones, Victoria Farmer, Sheila Williams, Barbara Galland and Rachael Taylor
Although 24-hour time-use data are increasingly being examined in relation to indices of health, consensus has yet to be reached about the best way to present estimates from compositional analyses. This analysis explored the impact of different presentations of results when assessing the relationship between 24-hour time-use and body mass index (BMI) z-score using compositional analysis of 5-day actigraphy data in 742 children. First it was found that reallocating non-wear time to day-time components only (sedentary behavior, light physical activity, and moderate-to-vigorous physical activity [MVPA]) before normalization to 24 hours provided stronger estimates with BMI z-score than simply removing non-wear time before normalization. Estimates for sleep time were substantially affected, where associations with BMI z-score nearly doubled (mean difference [95% CI] in BMI z-score for 10% longer sleep were −0.20 [−0.32, −0.08] compared to −0.11 [−0.23, 0.002]). Presenting estimates in terms of a greater number of minutes in a component, relative to all others, showed MVPA to be the strongest predictor of BMI z-score, while estimates in terms of the proportion of minutes showed sleep to be the strongest predictor. Both presentations have value. However, presentations in terms of one-to-one “substitutions” of time may need careful interpretation due to the uneven distribution of time in each component. In conclusion, when analyzing relationships between 24-hour time-use and health outcomes, non-wear time and presentation of estimates can impact final conclusions. As a result, the current understanding of the importance of sleep for child health may be underestimated.
Mayrena I. Hernandez, Kevin M. Biese, Dan A. Schaefer, Eric G. Post, David R. Bell and M. Alison Brooks
Context: Sport specialization among youth athletes has been associated with increased risk of overuse injuries. Previous research demonstrates that children perceive specialization to be beneficial in making their high school team and receiving athletic college scholarships. Previous research demonstrates that parents play a significant role in their child’s sport experience. However, it is unknown if parents and children answer questions related to specialization factors in a similar manner. Objective: To evaluate the beliefs of youth athletes and parents on factors related to sport specialization and evaluate the level of agreement between dyads on sports specialization. Design: Cross-sectional. Setting: Online and paper surveys. Patients or Other Participants: Aim 1: 1998 participants (993 children and 1005 parents). Aim 2: 77 paired parent–child dyads. Interventions: Self-administered survey. Main Outcome Measures: The responses were summarized via frequency and proportions (%). Chi-squares were calculated between parent and child responses. Kappa coefficients were calculated for dyads to determine level of agreement. Sport specialization was classified using a common 3-point scale. Results: The parents were more concerned about risk of injury in sports compared with children (P < .001, χ2 = 231.4; parent: extremely: 7.1%; child: extremely: 3.7%). However, children were more likely to believe that specialization was associated with their chances of obtaining an athletic college scholarship compared with parents (P < .001, χ2 = 201.6; parent: very/extremely likely: 13.7%; child: very/extremely likely: 15.8%). Dyad subanalysis indicated a moderate level of agreement for “quitting other sports to focus on one sport” (κ = .50) and a low level of agreement for “identifying a primary sport” (κ = .30) and “training >8 months per year in primary sport” (κ = .32). Conclusions: Parents and youth athletes had differing beliefs on the factors related to sport specialization. Dyad analysis shows that parents and children answer sport specialization classification questions differently. Health care providers should be aware of these differences, and messaging should be individualized to the audience.
Theodore Kent Kessinger, Bridget Melton, Theresa Miyashita and Greg Ryan
Clinical Scenario: Manipulation of exercise variables in resistance training (RT) is an important component in the development of muscular strength, power, and hypertrophy. Currently, most research centers on untrained or recreationally trained subjects. This critically appraised topic focuses on studies that center on the well-trained subject with regard to frequency of training. Clinical Question: In well-trained male subjects, is there an association between RT frequency and the development of muscular strength and hypertrophy? Summary of Key Findings: Four studies met the inclusion criteria and were included for analysis. All studies showed that lower-frequency training could elicit muscular strength and hypertrophy increases. One study suggested that a higher frequency compared with a lower frequency may provide a slight benefit to hypertrophic development. One study reported a greater level of delayed onset muscle soreness with lower frequency training. The 4 studies demonstrate support for the clinical question. Clinical Bottom Line: Current evidence suggests that lower-frequency RT produces equal to greater improvements on muscular strength and hypertrophy in comparison to higher-frequency RT when volume is equated. The evidence is particularly convincing when lower-frequency RT is associated with a total-body training protocol in well-trained male subjects. Strength of Recommendation: There is moderate-to-strong evidence to suggest that lower-frequency RT, when volume is equated, will produce equal to greater improvements on muscular strength and hypertrophy in comparison to higher-frequency RT.