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Danny M. Pincivero, Rachael R. Polen and Brittany N. Byrd

The objective of the present study was to examine the relationship between maximal effort force production and anthropometric measures of upper-arm volume. Thirty healthy young participants (15 women) performed 5 isokinetic concentric and eccentric maximal effort elbow flexor/extensor contractions on separate days. Measures of arm length, circumference, and skinfold/subcutaneous fat thickness were used to obtain a measure of arm volume, modeled as 2 separate right-angle frustra. Single-variable regression analyses demonstrated significant (P < .001) second-order polynomial relationships between maximal effort elbow flexor and extensor force with arm volume (r 2 = .63–.86). The major findings demonstrated that strong and positive relations between maximal force production and estimates of limb volume can be observed using nonlinear modeling and a closer geometric representation of the exercising limb.

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Xihe Zhu and Justin A. Haegele

The purpose of this study was to examine reactivity to accelerometer measurement in children with visual impairments (VI), their sighted siblings, and their parents. A sample of 66 participants (including 22 children with VI, 22 siblings, and 22 parents) completed a demographic survey and wore triaxial accelerometers for at least 4 consecutive days for 8 hr. An analysis of covariances with repeated measures was conducted, controlling for participant gender. Children with VI had 8.1% less moderate to vigorous physical activity time on Day 1 than Days 2–4 average. Their sighted siblings and parents had 7.8% and 7.1% more moderate to vigorous physical activity time on Day 1 than their Days 2–4 average, respectively. The reactivity percentage for parents and children without VI is consistent with existing literature. However, an inverse reactivity for children with VI was found, which is a unique contribution to the literature and will have implications for researchers using accelerometers for this population.

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Kevin Deschamps, Giovanni Matricali, Maarten Eerdekens, Sander Wuite, Alberto Leardini and Filip Staes

Foot structure and kinematics have long been considered as risk factors for foot and lower-limb running injuries. The authors aimed at investigating foot joint kinetics to unravel their receptive and propulsive characteristics while running barefoot, both with rearfoot and with midfoot striking strategies. Power absorption and generation occurring at different joints of the foot in 6 asymptomatic adults were calculated using both a 3-segment and a 4-segment kinetic model. An inverse dynamic approach was used to quantify mechanical power. Major power absorption and generation characteristics were observed at the ankle joint complex as well as at the Chopart joint in both the rearfoot and the midfoot striking strategies. The power at the Lisfranc joint, quantified by the 4-segment kinetic model, was predominantly generated in both strategies, and at the toes, it was absorbed. The overall results show a large variability in the receptive and propulsive characteristics among the analyzed joints in both striking strategies. The present study may provide novel insight for clinical decision making to address foot and lower-limb injuries and to guide athletes in the adoption of different striking strategies during running.

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Wesley J. Wilson and K. Andrew R. Richards

Occupational socialization theory has been used to understand the recruitment, education, and socialization of physical education teachers for nearly 40 yr. It has, however, only recently been applied to the study of adapted physical education teachers. The purpose of this descriptive case study was to understand the socialization of preservice teachers in an adapted physical education teacher education graduate-level program. Participants included 17 purposefully selected preservice teachers (5 male and 12 female) enrolled in a yearlong graduate-level adapted physical education teacher education program. Qualitative data were collected using interviews, reflective journaling, and field notes taken during teaching and coursework observations. Data analysis resulted in the construction of 3 themes: overcoming contextual challenges to meet learners’ needs, the importance of field-based teacher education, and coping with the challenges of marginalization. The discussion connects to and advances occupational socialization theory in adapted physical education and suggests that professional socialization may have a more profound influence on preservice adapted physical education teachers than on their physical education counterparts.

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Ana F. Silva, Pedro Figueiredo, Sara Morais, João P. Vilas-Boas, Ricardo J. Fernandes and Ludovic Seifert

This study aimed to examine young swimmers’ behavioral flexibility when facing different task constraints, such as swimming speed and stroke frequency. Eighteen (five boys and 13 girls) 13- to 15-year-old swimmers performed a 15 × 50-m front crawl with five trials, at 100%, 90%, and 70% each of their 50 m maximal swimming speed and randomly at 90%, 95%, 100%, 105%, and 110% of their preferred stroke frequency. Seven aerial and six underwater cameras were used to assess kinematics (one cycle), with upper-limb coordination computed through a continuous relative phase and index of coordination. A cluster analysis identified six patterns of coordination used by swimmers when facing various speed and stroke frequency constraints. The patterns’ nature and the way the swimmers shifted between them are more important than getting the highest number of patterns (range of repertoire), that is, a change in the motor pattern in order to adapt correctly is more important than being able to execute a great number of patterns.

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Tomoko Aoki, Hayato Tsuda and Hiroshi Kinoshita

The purpose of this study was to examine finger motor function in terms of temporal and force characteristics during rapid single-finger tapping in older adults. Ten older and 10 young males performed maximum frequency tapping by the index, middle, ring, or little finger. Nontapping fingers were maintained in contact with designated keys during tasks. Key-contact force for each of the fingers was monitored using four force transducers. The older subjects had slower tapping rates of all fingers during single-finger tapping than the young subjects. The average forces exerted by the nontapping fingers were larger for the older subjects than for the young subjects during tapping with the ring and little fingers. The ranges of the nontapping finger forces were larger for the older subjects during tapping by the middle, ring, and little fingers than for the young subjects. Thus, the motor abilities of the fingers evaluated by rapid single-finger tapping decline in older adults compared with young adults in terms of both movement speed and finger independence.

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Soubhagyalaxmi Mohanty, Balaram Pradhan and Alex Hankey

Physical activities provide fundamental benefits to children’s health and well-being. They are vital for development and healthy life, but participation of children with visual impairment is limited. Herein, the authors report results of a 16-wk yoga program, evaluating its effects on physical fitness in children with visual impairment. Eighty-three children age 9–16 years (12.37 ± 2.19) participated in a 2-arm, single-blind wait-list-controlled study at a residential school in south India. Participants (yoga group 41, controls 42) were assessed on muscle strength, flexibility, endurance, coordination, and respiratory health. Significant improvements in physical fitness were observed after the yoga intervention (Group × Time interactions for right-hand grip strength, p < .001; sit-up, p < .001; sit and reach, p < .001; bilateral plate tapping, p < .001; and peak expiratory flow rate, p < .001). Left-hand grip strength showed main effects of time, although there were no Group × Time interactions. Results demonstrate yoga’s ability to improve a wide range of physical variables in children with visual impairment.

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Cameron T. Gibbons, Polemnia G. Amazeen and Aaron D. Likens

Variability is commonly observed in complex behavior, such as the maintenance of upright posture. The current study examines the value added by using nonlinear measures of variability to identify dynamic stability instead of linear measures that reflect average fluctuations about a mean state. The largest Lyapunov exponent (λ1) and SD were calculated on mediolateral movement as participants performed a sit-to-stand task on a stable and unstable platform. Both measures identified changes in movement across postures, but results diverged when participants stood on the unstable platform. Large SD indicated an increase in movement variability, but small λ1 identified those movements as stable and controlled. The results suggest that a combination of linear and nonlinear analyses is useful in identifying the proportion of observed variability that may be attributed to structured, controlled sources. Nonlinear measures of variability, like λ1, can further be used to make predictions about transitions between stable postures and to identify a system’s resistance to disruption from external perturbations. Those features make nonlinear analyses highly applicable to both human movement research and clinical practice.

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Kirsti Van Dornick and Nancy L.I. Spencer

The purpose of this study was to examine the classification experiences (perspectives and reflections) of paraswimmers. Classification provides a structure for parasport, with the goal of reducing the impact of impairment on the outcome of competition. Guided by interpretive description, nine paraswimmers ranging in swimming experience and sport class were interviewed. Reflective notes were also collected. Transcribed interviews were analyzed inductively, followed by a deductive analysis using Nordenfelt’s dignity framework. Three themes represent the findings: access, diversity, and (un)certainty. Despite several positive experiences, paraswimmers also discussed inconsistencies in the process leading them to question competition fairness and classification accuracy. These findings suggest that continued efforts to improve the classification system are required. In addition, paraswimmers and their allies (e.g., coaches) require more information about the classification process to better understand the outcomes and to effectively advocate for their needs.

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Robin S. Vealey, Nick Galli and Robert J. Harmison

In this commentary, we respond to Scherzer and Reel’s concerns over the Certified Mental Performance Consultant® (CMPC®) certification program requirements, particularly the certification exam. A reframing is suggested, in which the exam and recertification requirements are viewed as exciting historical milestones and an opportunity for individual professional growth as opposed to a personal inconvenience. In addition, some historical context and rationale for specific aspects of the CMPC certification program are provided, including the rationale for the CMPC credential.