bluuebunny/crossref_metadata_2025 huggingface dataset:
Evidence of Motor Equivalence in a Pointing Task Involving Locomotion
Authors: Marteniuk Ronald G. , Ivens Chris J. , Bertram Christopher P.
Published: August 2016

A pointing task was performed both while subjects stood beside and while subjects walked past targets that involved differing movement amplitudes and differing sizes. The hand kinematics were considered relative both to a fixed frame of reference in the movement environment (end effector kinematics) and to the subject's body (kinematics of the hand alone). From the former view, there were few differences between standing and walking versions of the task, indicating similarity of the kinematics of the hand. However, when the hand was considered alone, marked differences in the kinematics and spatial trajectories between standing and walking were achieved. Furthermore, kinematic analyses of the trunk showed that subjects used differing amounts of both flexion-extension and rotation movements at the waist depending on whether they were standing or walking as well as on the constraints imposed by target width and movement amplitude. The present results demonstrate the existence of motor equivalence in a combined upper and lower extremity task and that this motor equivalence is a control strategy to cope with increasing task demands. Given the complexity involved in controlling the arm, the torso, and the legs (during locomotion), the movements involved in the present tasks appear to be planned and controlled by considering the whole body as a single unit.
Against a Final Ballistic Process in the Control of Voluntary Action: Evidence Using the Hoffmann Reflex
Authors: McGarry Tim , Inglis J. Timothy , Franks Ian M.
Published: August 2016

Reduced surface electromyogram (EMG) onsets, observed in some cases when trying to stop an earlier intended action before it begins, were taken to suggest a control process that remains open to stopping right up to the point of motor discharge. This interpretation argues against a final ballistic (involuntary) process in the control of voluntary action. That a final ballistic process may receive reduced input shortly before its manifestation as reduced output (i.e., motor discharge), however, provides for an alternative interpretation of these same data. In this study we used the Hoffmann (H) reflex to further investigate for stopping effects in the brief interval before voluntary motor discharge. Late stopping effects on the facilitated H-reflex within the time window that a final ballistic process would otherwise be expected (i.e, shortly before EMG onset) were observed in some instances. We conclude from these data good evidence against a final ballistic process in the control of voluntary action.
Planning Reaching and Grasping Movements: The Problem of Obstacle Avoidance
Authors: Vaughan Jonathan , Rosenbaum David A. , Meulenbroek Ruud G. J.
Published: August 2016

In this article, we review a model of the movement-planning processes that people use for direct reaching, reaching around obstacles, and grasping, and we present observations of subjects' repeated movements of the hand to touch 2 target locations, circumventing an intervening obstacle. The model defines an obstacle as a posture that, if adopted, would intersect with any part of the environment (including the actor himself or herself). The model finds a trajectory that is likely to bring the end-effector to me target by means of a one- or two-stage planning process. Each stage exploits the principles of instance retrieval and instance generation. In the first stage, a goal posture is identified, and the trajectory of a direct transition to that posture is tested for collision. If that direct movement has no collision, the movement to the target is immediately executed in joint space. If. however, the direct movement is foreseen to result in a collision, a second planning stage is invoked. The second planning stage identifies a via posture, movement through which will probably avoid the collision. Movement to and from the via posture is then superimposed on the main movement to the target so that the combined movement reaches the target without colliding with intervening obstacles. We describe the details of instance retrieval and instance generation for each of these planning stages and compare the model's performance with the observed kinematics of direct movements as well as movements around an obstacle. Then we suggest how the model might contribute to the study of movements in people with motor disorders such as spastic hemiparesis.
The Regulation of Fine Movements in Patients with Charcot Marie Tooth, Type la: Some Ideas about Continuous Adaptation
Authors: Mulder Theo , den Otter Rob , van Engelen Baziel
Published: August 2016

The flexibility of the human motor system is remarkable. Even when parts of the system are damaged, the output often remains optimal or near-optimal. The neuromotor system is designed to keep the output optimal by shifting between input sources. This capability is termed the principle of continuous adaptation. This article describes an experiment in which patients suffering from a hereditary motor and sensory neuropathy, type la (Charcot Marie Tooth disease, type la), had to perform fine motor movements. We examined whether they were able to regulate these movements in spite of the fact that the somatosensory input and motor output was substantially impaired as a result of the chronic, slowly progressing neuropathy. It was predicted that these patients were able to perform fine movements as long as the movements were well known and over-learned. Furthermore, it was predicted that these patients would compensate for the loss of somatosensory information by becoming more dependent on vision. A second prediction was that the quality of the motor performance would break down when these patients had to perform a novel motor pattern. The performance of the patients (n = 10) was contrasted with the performance of 20 healthy subjects. The results indicated that the patients, indeed, were able to perform the over-learned movements and that their performance deteriorated significantly when they had to perform a novel motor pattern. No indication, however, could be found for visual compensation.
The Role of Vision in Control of Orientation in a Back Tuck Somersault
Authors: Davlin Christina D. , Sands William A. , Shultz Barry B.
Published: August 2016

During a back tuck somersault, the angular velocity of the head is thought to surpass the visual system's ability to maintain a distinct and continuous picture of the environment. The primary objectives of this research were to determine if differences existed with regard to trunk and lower body kinematics, as well as landing balance, when gymnasts perform back tuck somersaults under different vision conditions. Ten female gymnasts (age = 11.6 ± 2.67 years, competitive level = 8 ± 1.15, and training time in gymnastics = 5.9 ± 1.63 years) performed back tuck somersaults under 4 vision conditions while wearing electromagnetic sensors that allowed automatic digitizing. Although no significant differences were found between vision conditions with regard to timing, joint angles, and joint angular velocities, gymnasts were more stable at landing under conditions that allowed vision during either the entire somersault or the last half of me somersault.
The One-Target Advantage: Advanced Preparation or Online Processing?
Authors: Lavrysen Ann , Helsen Werner F. , Elliott Digby , Adam Jos J.
Published: August 2016

The one-target advantage refers to a shorter movement time for one-target aiming movements, in comparison to aiming attempts followed by a second movement. Theoretical explanations of the one-target advantage vary in the extent to which they attribute this phenomenon to prior planning or to online control mechanisms. In this research, we attempted to gain insight into the control of sequential aiming movements by manipulating the availability of online feedback during this first or second movement component. When the participants' vision was occluded during the first movement (Experiment 1) or during the second movement (Experiment 2), their performance was affected, showing that vision was important for online control of the movement sequence. A one-target advantage was found when the second movement was in the same direction as me first, but not when it was reversed with respect to the home button. Both prior planning and online control processes contribute to the one-target advantage. The degree to which these processes are important for limb control depends on the specific task demands.
rTMS to the Supplementary Motor Area Disrupts Bimanual Coordination
Authors: Obhi Sukhvinder S. , Haggard Patrick , Taylor John , Pascual-Leone Alvaro
Published: August 2016

Bimanual coordination tasks form an essential part of our behaviour. One brain region thought to be involved in bimanual coordination is the supplementary motor area (SMA). We used repetitive transcranial magnetic stimulation (rTMS) at 1 Hz for 5 min to create a temporary virtual lesion of the rostral portion of the human SMA immediately prior to performance of a goal-directed bimanual coordination task. In two control conditions, participants underwent sham stimulation or stimulation over the primary motor cortex (MI). The experimental task was to open a drawer with the left hand, catch a ball with the right hand, and reinsert the ball into the drawer through an aperture just big enough for the ball to pass through, again with the right hand. Hence, the actions of one hand depend upon the actions of the other. We calculated time intervals between the successive component actions of one hand (unimanual intervals) and actions of both hands (bimanual intervals) and analyzed these intervals separately. Interestingly, none of the unimanual intervals were affected by the rTMS, but the variability of a critical bimanual interval—the time between the left hand opening the drawer and the right hand starting to move to catch the ball—was increased by rTMS over the rostral parts of the SMA. No such effect was seen following rTMS over MI or after sham rTMS. Our results suggest that the rostral parts of the SMA play an important role in aspects of functional bimanual tasks, which involve tight temporal coordination between different motor actions of the two hands.
Further Insights into Post-exercise Effects on H-Reflexes and Motor Evoked Potentials of the Flexor Carpi Radialis Muscles
Authors: Kato Takashi , Takeda Yusaku , Tsuji Toshio , Kasai Tatsuya
Published: August 2016

The present study investigated the relative contribution of the cortical and spinal mechanisms for post-exercise excitability changes in human motoneurons. Seven healthy right-handed adults with no known neuromuscular disabilities performed an isometric voluntary wrist flexion at submaximum continuous exertion. After the subjects continued muscle contraction until volitional fatigue, the H-reflexes induced by an electric stimulation and motor evoked potentials (MEPs) induced by a transcranial magnetic stimulation (TMS) from a flexor carpi radialis (FCR) muscle were recorded 7 times every 20 s. The H-reflex was used to assess excitability changes at the spinal level, and the MEP was used to study excitability changes at the cortical level. H-reflexes showed a depression (30% of control value) soon after the cessation of wrist flexion and recovered with time thereafter. On the other hand, an early (short latency) MEP showed facilitation immediately after the cessation of wrist flexion (50% of control value) and thereafter decreased. A possible mechanism for the contradictory results of the 2 tests, in spite of focusing on the same motoneuron pool, might be the different test potential sizes between them. In addition, a late (long latency) MEP response appeared with increasing exercise. With regard to the occurrence of late MEP response, a central mechanism may be proposed to explain the origin—that is, neural pathways with a high threshold that do not participate under normal circumstances might respond to an emergency level of muscle exercise, probably reflecting central effects of fatigue.
Drift in Blind Reciprocal Aiming Movements
Authors: Rantanen Esa M. , Rosenbaum David A.
Published: August 2016

There is anecdotal evidence of drift in various reciprocal motor tasks, but as far as is known, no investigations into this phenomenon have been reported. Yet, systematic drift can potentially explain a significant proportion of the total variability in motor output. Three experiments were conducted to ascertain the nature of drift in reciprocal aiming tasks and to develop methods and measures to isolate and quantify drift for analyses. We also evaluated a computational posture-based model of reaching movements with respect to the findings of the experiments. Drift was observed in all three experiments, generally toward the middle of the joint motility range. Simulations based on the model produced drift to the middle of the task movement range rather than middle of the joint movement range. Adding noise to the model could increase its power for simulating the underlying principles of movement control as reflected in performance features such as drift.
Multiple Time Scales and Multiform Dynamics in Learning to Juggle
Authors: Huys Raoul , Daffertshofer Andreas , Beek Peter J.
Published: August 2016

To study the acquisition of perceptual-motor skills as an instance of dynamic pattern formation, we examined the evolution of postural sway and eye and head movements in relation to changes in performance, while 13 novices practiced 3-ball cascade juggling for 9 weeks. Ball trajectories, postural sway, and eye and head movements were recorded repeatedly. Performance improved exponentially, both in terms of the number of consecutive throws and the degree of frequency and phase locking between the ball trajectories. These aspects of performance evolved at different time scales, indicating the presence of a temporal hierarchy in learning. Postural sway, and eye and head movements were often 3:2 and sometimes 3:1 frequency locked to the ball trajectories. As a rule, the amplitudes of these oscillatory processes decreased exponentially at rates similar to that of the increase in the degree of phase locking between the balls. In contrast, the coordination between these oscillatory processes evolved exponentially at different time scales, apart from some erratic evolutions. Collectively, these findings indicate that skill acquisition in the perceptual-motor domain involves multiple time scales and multiform dynamics, both in terms of the development of the goal behavior itself and the evolution of the processes subserving this goal behavior.
Modeling Kinematics and Dynamics of Human Arm Movements
Authors: Admiraal Marjan A. , Kusters Martijn J.M.A.M. , Gielen Stan C.A.M.
Published: August 2016

A central problem in motor control relates to the coordination of the arm's many degrees of freedom. This problem concerns the many arm postures (kinematics) that correspond to the same hand position in space and the movement trajectories between begin and end position (dynamics) that result in the same arm postures. The aim of this study was to compare the predictions for arm kinematics by various models on human motor control with experimental data and to study the relation between kinematics and dynamics. Goal-directed arm movements were measured in 3-D space toward far and near targets. The results demonstrate that arm postures for a particular target depend on previous arm postures, contradicting Donders's law. The minimum-work and minimum-torque-change models, on the other hand, predict a much larger effect of initial posture than observed. These data suggest that both kinematics and dynamics affect postures and that their relative contribution might depend on instruction and task complexity.
Force Levels in Uni- and Bimanual Isometric Tasks Affect Variability Measures Differently Throughout Lifespan
Authors: Smits-Engelsman Bouwien C.M. , Van Galen Gerard P. , Duysens Jacques
Published: August 2016

Ninety-four participants (age 5–93 years) performed isometric force production tasks at five different levels of their maximum voluntary contraction (MVC) with either one or two index fingers. Research questions were whether variability measures in the bimanual task condition were different compared to the unimanual condition and whether this difference showed a developmental trend. Results showed that force regulation was more demanding during bimanual tasks (33% increase in error). During development signal-to-noise ratio (SNR) increased threefold from 5–12 years of age and again 60% from 12 years to adulthood. SNR for the elderly was comparable to values of 9 to 10-year-olds. SNR decreased in the bimanual task, particularly for the older persons. For adults and elderly, optimal SNR levels were observed around 36% of their MVC. In younger children, however, the inverted U-shape in the SNR over the full range of forces was not yet present.
Comparison of Pallidal and Subthalamic Stimulation on Force Control in Patient's with Parkinson's Disease
Authors: Alberts Jay L. , Elder Christopher M. , Okun Michael S. , Vitek Jerrold L.
Published: August 2016

The aim of this study was to determine the effects of unilateral deep brain stimulation (DBS) on the control and coordination of grasping forces produced by Parkinson's disease (PD) patients. Ten advanced PD patients with unilateral DBS in the globus pallidus (GPi) or the subthalamic nucleus (STN) (5 patients in each group) performed a functional bimanual dexterous manipulation task. Experiments were performed in the “Off” medication state with DBS “On” and “Off.” DBS resulted in (a) significant clinical improvements, (b) greater maximum grip force for both limbs, (c) reduced movement time, and (d) bilateral coupling of grasping forces. There were no significant differences between the GPi and STN groups for any clinical or kinematic measures. DBS of the GPi and STN leads to an improvement in the motor functioning of advanced PD patients. Improvement in force-timing specification during DBS might allow PD patients to employ a feedforward method of force control.
Comparison and Relationship of VO2peak and Physical Activity Patterns in Elementary and High School Females
Authors: Loftin Mark , Strikmiller Patricia , Warren Barbara , Myers Leann , Schroth Leslie , Pittman James , Harsha David , Sothern Melinda
Published: August 2016

Peak cardiorespiratory responses, physical activity patterns, and the association of VO2peak and physical activity were examined in 16 elementary (ES) and 16 high school (HS) females. Peak responses were assessed during treadmill running, and physical activity patterns were examined over two 12-hour weekdays. Results indicated similar relative VO2peak responses between groups (ES: M = 46.8 ml · kg−1 · min−1;HS:M = 46.6 ml · kg−1 · min−1). No statistical differences (p ≤ .05) were noted when moderate to vigorous physical activity (MVPA) and vigorous physical activity (VPA) were compared. Also, a three-way (Group × HR level × Sustained minutes) ANOVA revealed no statistical differences. A median correlation (r = .27) was found from 8 independent correlations of habitual physical activity and VO2peak. ES and HS appeared similar in regard to VO2peak, accumulative and sustained MVPA and VPA. Low levels of sustained MVPA and VPA (≥ 10 min) were evident in both groups.
Using the Computer Science and Applications (CSA) Activity Monitor in Preschool Children
Authors: Fairweather Sheila C. , Reilly John J. , Grant Stanley , Whittaker Arthur , Paton James Y.
Published: August 2016

The primary aim of this study was to assess the ability of the CSA accelerometer to measure physical activity in preschool children. A secondary aim was to examine inter-instrument differences and the effect of accelerometer placement on output. Eleven subjects (mean age = 4.0 years, SD = 0.4) wore the CSA-7164 for a 45-min preschool exercise class. They were observed throughout the class, and their engagement in activity was quantified using the Children’s Physical Activity Form (CPAF). The effect of accelerometer positioning (left vs. right hip) was assessed in 10 subjects over 2 days. CSA output during the class was highly correlated with the CPAF score (r = 0.87, p < .001), and rank order correlations between the 2 methods were also highly significant (r = 0.79, p < .01). Differences in CSA output between left and right hip reached statistical significance (paired t, p < .05), but these differences were small and probably of limited biological significance. The CSA appears to be an appropriate tool for assessment of physical activity in preschool children, but further studies on stability of activity as measured by CSA, as well as its validity, are urged.
Statistical Techniques for Interpreting Body Size–Related Exercise Performance during Growth
Authors: Welsman Joanne R. , Armstrong Neil
Published: August 2016

This paper reviews some of the statistical methods available for controlling for body size differences in the interpretation of developmental changes in exercise performance. For cross-sectional data analysis simple per body mass ratio scaling continues to be widely used, but is frequently ineffective as the computed ratio remains correlated with body mass. Linear regression techniques may distinguish group differences more appropriately but, as illustrated, only allometric (log-linear regression) scaling appropriately removes body size differences while accommodating the heteroscedasticity common in exercise performance data. The analysis and interpretation of longitudinal data within an allometric framework is complex. More established methods such as ontogenetic allometry allow insights into individual size-function relationships but are unable to describe adequately population effects or changes in the magnitude of the response. The recently developed multilevel regression modeling technique represents a flexible and sensitive solution to such problems allowing both individual and group responses to be modeled concurrently.
The Relationship between Physical Activity, Self-Esteem, and Academic Achievement in 12-Year-Old Children
Authors: Tremblay Mark S. , Inman J. Wyatt , Willms J. Douglas
Published: August 2016

This study examined the relationships between children’s reported levels of physical activity, body-mass index, self-esteem, and reading and mathematics scores, while controlling for sex, family structure, and socioeconomic status. The data were collected from the full population of Grade 6 students (N = 6,923) in New Brunswick (NB), Canada in 1996, as part of the Elementary School Climate Study, and the NB Department of Education’s Grade 6 Assessment. Physical activity had a negative relationship with body-mass index. Physical activity had a positive relationship with self-esteem, and a trivial negative relationship with academic achievement. The analysis revealed that both females and males who were more physically active had considerably higher levels of self-esteem. The study suggests that the relationship between physical activity and academic achievement is weak. For some children, physical activity may be indirectly related to enhanced academic performance by improving physical health and self-esteem.
Reliability of Effort Perception for Regulating Exercise Intensity in Children Using the Cart and Load Effort Rating (CALER) Scale
Authors: Eston Roger G. , Parfitt Gaynor , Campbell Laura , Lamb Kevin L.
Published: August 2016

The purpose of this study was to assess whether young children could reliability regulate exercise intensity production after several practice trials, without reference to objective feedback measures. The study used a new 10-point scale (Cart and Load Effort Rating [CALER] Scale), which depicts a child on a bicycle, at various stages of exertion, towing a cart in which the load increases progressively. After warm-up, 20 children, aged 7–10 years, performed an intermittent, effort production protocol at CALER 2, 5, and 8 on a cycle ergometer. This was repeated on three further occasions in the next 4 weeks. An increase in PO across trials (44, 65, and 79 W at CALER 2, 5, and 8, respectively) confirmed that the children understood the scale. A Bland and Altman limits of agreement (LoA) analysis and an intraclass correlation analysis (ICC) between trials (T) indicated that reliability improved with practice. Intertrial comparisons of overall reliability from T1 to T2 and from T3 to T4 ranged from 0.76 to 0.97 and an improvement in the overall bias ± 95% limits of agreement from −12 ± 19 W to 0 ± 10 W. This study is the first to apply more than two repeated effort production trials in young children and provides strong evidence that practice improves the reliability of effort perception in children. The data also provide preliminary evidence for the validity of the CALER Scale in children aged 7–10 years.
Motor Fitness in Pre-Primary School Children: The EUROFIT Motor Fitness Test Explored on 5–7-Year-Old Children
Authors: Fjørtoft Ingunn
Published: August 2016

This article is a contribution to the experience of testing motor fitness and exploring the EUROFIT test in young children. In the age group 5–7 years, the motor fitness tests showed strong dependency on age and a small dependence on sex. Body weight and height did not appear to have any impact on the test variables for this age group. The reliability test showed significant difference between test and retest in the plate tapping test only. The reproducibility was low in bent arm hang and flamingo balance, with coefficients of variation of 67%. Modest validity of the flamingo balance test and the standing broad jump test was confirmed with correlations of 0.43 and 0.52, respectively, by laboratory testing on a force platform. Factor analyses extracted 3 components, which explained 62% of the total variance, but no single component could explain general motor fitness. The EUROFIT Motor Fitness Test appeared to be applicable also in young children, but the reproducibility of two test items was questionable. Modification of test items was suggested to fit this age group.
Video Center Games: Energy Cost and Children’s Behaviors
Authors: Ridley Kate , Olds Tim
Published: August 2016

Time spent playing video games has been linked to increases in childhood obesity and sedentary behavior. However, “new generation” video games require total body movement and greater physical exertion. The aim of this study was to describe children’s behavior and energy expenditure while visiting video game centers. Observations were undertaken on 134 children’s activity patterns while playing at a video game center. The energy cost of 10 children (5 male and 5 female) aged 12.5 ± 0.5 yr, playing 4 popular video games was then measured. Gross energy cost ranged from 7.6 to 26.5 ml · kg−1 · min−1. Based on our observations, we estimate that the gross energy expenditure during a child’s typical session in a video game center will range from 2.3–2.6 METS.
Age- and Sex-Related Differences in Optimal Peak Power
Authors: Santos Amândio M.C. , Welsman Joanne R. , Croix Mark B.A. De Ste , Armstrong Neil
Published: August 2016

Age- and sex-related differences in optimal peak power (PPopt) and associated measures determined using a force-velocity (F-V) cycling test were examined in pre teenage, teenage and adult males and females. Absolute PPopt increased significantly with age in both males and females. With body mass controlled for using allometric scaling significant age related increases remained, an effect masked in the females when PPopt was expressed as W • kg−1. Sex differences in PPopt were minimal in the preteens but males demonstrated higher PPopt than females in both teenage and adult groups. These patterns of change with age and sex broadly reflect those obtained for Wingate Anaerobic Test determined PP but the use of a single non-optimized braking force underestimates the magnitude of any differences observed.
A Three Year Study of Coronary Heart Disease Risk Factors in Greek Adolescents
Authors: Bouziotas Constantin , Koutedakis Yiannis
Published: August 2016

We examined the prevalence of 14 modifiable CHD risk factors in a sample of 210 provincial Greek children as they progressed from age 12 to 14. It was found that 46.2% of boys and 49.5% of girls (p > 0.05) exhibited three or more risk factors at their 12th year, with values of 42% for boys and 51.1% (p > 0.05) for girls for their 13th year, and 29.4% for boys and 55% (p < 0.001) for girls in their 14th year. Risk factors with the highest prevalence in both sexes included low vigorous physical activity, low aerobic fitness, and elevated body fatness. The fact that boys exhibited progressively fewer risk factors with age was mainly attributed to increased time spent on vigorous physical activity (P < 0.001) and higher predicted oxygen intake (P < 0.001) with a concomitant decrease in body fat (P < 0.001). The opposite pattern demonstrated by girls was primarily due to elevated predicted % body fat (P < 0.05), % saturated fat intake (P < 0.05), total cholesterol (TC; P < 0.001), low-density lipoprotein cholesterol (LDL-C; P < 0.001), and decreased high-density lipoprotein cholesterol (HDL-C)/TC; P < 0.001). In conclusion, a high percentage of young adolescent Greek boys and girls exhibit three or more modifiable CHD risk factors. However, as the children progress from age 12 to 14, gender differences emerge regarding the development of their CHD risk profiles. The present data support the notion that preventive strategies for combating CHD should begin early in life.
Does Reactivity Exist in Children When Measuring Activity Levels with Unsealed Pedometers?
Authors: Ozdoba Robert , Corbin Charles , Le Masurier Guy
Published: August 2016

Reactivity refers to a change in activity patterns that results from participants’ awareness that their activity levels are being monitored. Previous research has demonstrated that children do not exhibit reactivity when mechanically sealed pedometers are used to measure activity levels. The purpose of this study was to determine whether reactivity occurred when using unsealed pedometers. Forty-five fourth-grade children wore pedometers for 8 days: 4 days sealed and 4 days unsealed. The results suggest that reactivity does not exist when using unsealed pedometers. Accidental resets proved to be a problem; therefore, the use of sealed pedometers might be necessary in order to prevent data losses.
Validation of the Digiwalker™ Pedometer for Measuring Physical Activity in Young Children
Authors: McKee David P. , Boreham Colin A.G. , Murphy Marie H. , Nevill Alan M.
Published: August 2016

Activity measurement using a uniaxial pedometer was validated against behavioral observation using the Children’s Activity Rating Scale (CARS) in 30 three- to four-year-old children in a nursery school setting. Correlations were calculated for individual children, whereas the relationship for the total group was investigated using multilevel linear regression. The mean counts for boys and girls for the Digiwalker™ were 66.8 (± 64.0) and 47.4 (± 61.3; p < .01) steps per 3 minutes, respectively, whereas the mean CARS scores for boys and girls were 1.8 (± 0.6) and 1.6 (± 0.6; p < .01), respectively. Within-child correlations for CARS versus Digiwalker counts ranged from 0.64 to 0.95 with a median value of 0.86, whereas the multilevel analysis provided strong evidence of a relationship between CARS and Digiwalker (all p < .001). Data from the current study show that gender differences in physical levels exist in very young children and support the utility of the Digiwalker pedometer for assessing physical activity in this age group.
A Movement-Analysis Comparison in Two Models of Junior Sport
Authors: Hartwig Timothy B. , Naughton Geraldine
Published: August 2016

Despite widespread encouragement for children to participate in sport, the efficacy of early sporting pathways remains underexplored. We compared a rotational junior-sport model combining skills from rugby, cricket, and netball with a modified games model. Motion analysis was used to quantify movement. Results revealed no differences between sporting models in relative percent time spent stationary (p = .32), walking (p = .89), jogging (p = .45), and fast running (p =.06). The rotational model had a greater number of skill-development opportunities per minute (median = 3.4) compared with the modified games model (median = 1.1, p = .001). Promising results from varied and rotational skill exposure warrant further elucidation.
More than 10 Years after “The Horse Is Dead …”: Surely It Must Be Time to “Dismount”?!
Authors: Cale Lorraine , Harris Jo , Chen Ming-Hung
Published: August 2016

This article represents a response to an editorial piece written in Pediatric Exercise Science over 10 years ago by Thomas Rowland in which he debated fitness testing and asked whether the “horse” of fitness testing in schools was dead. Here, the authors revisit the debate and consider the progress that has been made with regard to fitness testing in schools in recent years. On the basis of findings from the literature and some of their research, the authors suggest that accepting the fact that the horse is dead would not be a bad thing. Their advice is certainly to pull tightly on the reigns, slow the horse down, and not allow fitness testing to dominate schools’ efforts to promote physical activity.
Profiling the Diet and Body Composition of Subelite Adolescent Rhythmic Gymnasts
Authors: D’Alessandro Claudia , Morelli Ester , Evangelisti Irene , Galetta Fabio , Franzoni Ferdinando , Lazzeri Donatella , Piazza Marina , Cupisti Adamasco
Published: August 2016

The aim of this study was to investigate the body composition and dietary intake of competitive club-level rhythmic gymnasts, who represent the larger cohort of the sport’s practitioners. Fifty-five rhythmic gymnasts and 55 nonathlete females (13–19 years of age) were seen individually to collect a dietary recall and to take anthropometric data and bioelectric-impedance analysis. Gymnasts had lower body-mass index and lesser skinfold thickness, although middle arm-muscle circumference was similar in the 2 groups. Gymnasts had lower body-fat measures but normal levels of fat-free mass (FFM) and body-cellular mass. Gymnasts had better dietary habits than the age-matched controls. Low levels of calcium, phosphorous, iron, and zinc and a disparity between reported energy intake and estimated energy requirement were observed in both groups.
Leisure Time Physical Activity, Screen Time, Social Background, and Environmental Variables in Adolescents
Authors: Mota Jorge , Gomes Helena , Almeida Mariana , Ribeiro José Carlos , Santos Maria Paula
Published: August 2016

This study analyzes the relationships between leisure time physical activity (LTPA), sedentary behaviors, socioeconomic status, and perceived environmental variables. The sample comprised 815 girls and 746 boys. In girls, non-LTPA participants reported significantly more screen time. Girls with safety concerns were more likely to be in the non-LTPA group (OR = 0.60) and those who agreed with the importance of aesthetics were more likely to be in the active-LTPA group (OR = 1.59). In girls, an increase of 1 hr of TV watching was a significant predictor of non-LTPA (OR = 0.38). LTPA for girls, but not for boys, seems to be influenced by certain modifiable factors of the built environment, as well as by time watching TV.
Exercise Evaluation of Upper- versus Lower-Extremity Blood Pressure Gradients in Pediatric and Young-Adult Participants
Authors: Knecht Sandra K. , Mays Wayne A. , Gerdes Yvette M. , Claytor Randal P. , Knilans Timothy K.
Published: August 2016

The aim of this study was to provide a normal reference for arm–leg blood pressure gradients in normal pediatric and young-adult patients before and after exercise. We assessed 216 normal participants by physical or echocardiographic exam, maximally tested using the James Cycle Protocol, with arm and leg blood pressures taken pre- and postexercise. Arm–leg gradients significantly increased from –5 mmHg at rest to 4, 2, and 1 mmHg 1, 3, and 4 min postexercise (p < .05). There was a small, statistically significant increase in arm-leg blood pressure with exercise, which is probably clinically insignificant. These data serve as a normal reference.
Maturity-Related Differences in Physical Activity among 13- to 14-Year-Old Adolescents
Authors: Wickel Eric E. , Eisenmann Joey C.
Published: August 2016

The age-related decline in physical activity during adolescence is well documented; however, little is known about differences in physical activity among early, average, and late maturing adolescents. The purpose of this study was to examine the relationship between maturity status and physical activity among 167 adolescents who were 13–14 years old. The maturity offset was derived and biological maturity groups were created. Habitual physical activity was determined with a pedometer over a 7-day period. No significant maturity-group differences were found for physical activity. The results of this study did not demonstrate significant differences in physical activity as determined by a pedometer among early, average, and late maturing 13- to 14-year-olds.
Estrogen Receptor α Polymorphism Modifies the Association between Childhood Exercise and Bone Mass: Follow-Up Study
Authors: Suuriniemi Miia , Suominen Harri , Mahonen Anitta , Alén Markku , Cheng Sulin
Published: August 2016

This follow-up study confirms our previous findings that the ER-α PvuII polymorphism (Pp) modulates the association between exercise and bone mass. The differences in bone properties of girls with consistently low physical activity (LLPA) and consistently high physical activity (HHPA) were evident only in those bearing the heterozygote ER-α genotype (Pp). In particular, areal bone mineral density of the total femur, bone mineral content and areal bone mineral density of the femoral neck, and bone mineral content and cortical thickness of the tibia shaft were significantly (p < .05) lower in the Pp girls with LLPA than in their HHPA counterparts. These findings might partly explain the genetic basis of human variation associated with exercise training.
Maturational Differences in Physical Self-Perceptions and the Relationship with Physical Activity in Early Adolescent Girls
Authors: Niven Ailsa G. , Fawkner Samantha G. , Knowles Ann-Marie , Stephenson Claire
Published: August 2016

This cross-sectional study examined the relationship between physical self-perceptions (PSPs), maturation, and physical activity and compared the strength of the relationships of biological and chronological age with PSPs in early adolescent girls (N = 208; mean age = 11.83 ± 0.39 years). Participants completed the Physical Activity Questionnaire for Older Children, the Children’s Physical Self-Perception Profile, and the Pubertal Development Scale. Results indicated that PSPs were significantly and moderately correlated with physical activity. There were no differences in physical activity between maturation stages. Girls who were in the early stages of maturation had significantly more positive perceptions of body attractiveness and physical self-worth than girls in the mid stages of maturation. There was no evidence of a relationship between PSPs and chronological age. This study provided further support for the relationship between PSPs and physical activity and the relationship between maturation and aspects of PSPs. In this age group, maturation does not appear to be related to physical activity or the PSPs most strongly influential on physical activity behavior.
Trends of Cardiovascular Risk Factors Clustering Over Time: A Study in Two Cohorts of Portuguese Adolescents
Authors: Martins Clarice , Silva Francisco , Santos Maria Paula , Ribeiro José Carlos , Mota Jorge
Published: August 2016

This study analyzes trends in CVD risk factors and aerobic performance. Two cross-sectional studies were performed including 138 (58 boys and 80 girls) in 1998 and 110 (44 boys and 66 girls) in 2003 adolescents. Although in cardiorespiratory fitness (CRF) boys performed better than girls, they had lower body mass index (BMI) and total cholesterol (TC) than girls. The data also showed a significant year effect (p = .000) for CRF in both boys and girls. The sex–age group interaction was not significant (p > .05). This cross-sectional study revealed a marked low CRF level over time in both boys and girls.
Augmented Muscle Vasodilatory Responses in Obese Children with Glu27 β2-Adrenoceptor Polymorphism
Authors: da Silva Alexandre G. , Ribeiro Mauricio M. , Trombetta Ivani C. , Nicolau Christiane , Frazzatto Eliana , Guazzelli Isabel , Matos Luciana N. J. , Halpern Alfredo , Negrão Carlos E. , Villares Sandra M.F.
Published: August 2016

This study examined forearm vasodilatation during mental challenge and exercise in 72 obese children (OC; age = 10 ± 0.1 years) homozygous with polymorphism in the allele 27 of the β2-adrenoceptors: Gln27 (n = 61) and Glu27 (n = 11). Forearm blood flow was recorded during 3 min of each using the Stroop color-word test (MS) and handgrip isometric exercise. Baseline hemodynamic and vascular measurements were similar. During the MS, peak forearm vascular conductance was significantly greater in group Glu27 (Δ = 0.35 ± 0.4 vs. 0.12 ± 0.1 units, respectively, p = .042). Similar results were found during exercise (Δ = 0.64 ± 0.1 vs. 0.13 ± 0.1 units, respectively, p = .035). Glu27 OC increased muscle vasodilatory responsiveness upon the MS and exercise.
The Relationship between Pedometer Step Counts and Estimated VO2Max as Determined by a Submaximal Fitness Test in Adolescents
Authors: Lubans David R. , Morgan Philip J. , Callister Robin , Collins Clare E.
Published: August 2016

The purpose of this study was to examine the relationship between pedometer step counts and estimated VO2max as determined by a submaximal exercise test. Participants (N = 115; 65 girls, 50 boys) wore pedometers for five days and completed the Queen’s College Step Test (QCST). Based on these results participants were classified as HIGH, MOD, or LOW cardiorespiratory fitness. Boys accumulated more steps per day (p < .05) than girls (12,766 ± 4,923 versus 10,887 ± 2,656). The relationship between estimated VO2max and mean steps/day was moderate (r = .34, p < .01). Participants classified as having HIGH fitness levels accumulated more steps/day than LOW-fit adolescents (p < .05). The results from this study suggest that estimated VO2max as determined by a submaximal exercise test is moderately associated with mean steps/day in adolescents.
Use of Session Rating of Perceived Exertion for Monitoring Resistance Exercise in Children Who Are Overweight or Obese
Authors: McGuigan Michael R. , Dayel Abdulaziz Al , Tod David , Foster Carl , Newton Robert U. , Pettigrew Simone
Published: August 2016

The purpose of this study was to investigate the use of the OMNI Resistance Exercise scale (OMNI-RES) for monitoring the intensity of different modes of resistance training in children who are overweight or obese. Sixty-one children (mean age = 9.7 ± 1.4 years) performed three resistance training sessions every week for 4 weeks. Each session consisted of three sets of 3–15 repetitions of eight different resistance exercises. OMNI-RES RPE measures (0–10) were obtained following each set and following the end of the exercise session. There was a significant difference between average RPE (1.68 ± 0.61) and Session RPE (3.10 ± 1.18) during the 4 weeks of training (p < .05). There was no significant change in session RPE over the 4 weeks of training. The correlation coefficient between average and session RPE values was significant (r = .88, p < .05). The findings of the current study indicate that the RPE values are higher when OMNI-RES measures are obtained following the whole training session than when obtained following every single set of exercise. This suggests that in children the session RPE provides different information to the average RPE across the entire session.
Aerobic Exercise Program Reduces Anger Expression among Overweight Children
Authors: Tkacz Joseph , Young-Hyman Deborah , Boyle Colleen A. , Davis Catherine L.
Published: August 2016

This study tested the effect of a structured aerobic exercise program on anger expression in healthy overweight children. Overweight sedentary children were randomly assigned to an aerobic exercise program or a no-exercise control condition. All children completed the Pediatric Anger Expression Scale at baseline and posttest. Anger Out and Anger Expression scores were lower for the exercise condition at posttest. Fitness improvements contributed significantly to final models, and points earned for adherence correlated negatively with posttest Anger Out. An aerobic exercise program might be an effective strategy to reduce anger expression, including reduction of aggressive behavior, in overweight children.
Aerobic Fitness Data for Dutch Adolescents (2002–2005)
Authors: Slinger Jantine , van Breda Eric , Kuipers Harm
Published: August 2016

The article presents the current performance capacity in 11–15 year old Dutch adolescents who participated in an incremental cycle test (n = 509) and or in a shuttle run test (N = 1,198). Cycle test results increased significantly with age in both genders, also after normalization to body weight. Shuttle run test results increased significantly with age only in boys. Compared with previous data, the absolute performance capacity in the cycle tests was comparable to data from 15 years ago, whereas the performance capacity normalized to kg body weight and the shuttle run test results seem to be fairly lower compared with the former data.
Exercise Leukocyte Profiles in Healthy, Type 1 Diabetic, Overweight, and Asthmatic Children
Authors: Rosa Jaime S. , Schwindt Christina D. , Oliver Stacy R. , Leu Szu-Yun , Flores Rebecca L. , Galassetti Pietro R.
Published: August 2016

Leukocytosis contributes to exercise-induced immune modulation, which is a mechanism of cardiovascular protection. However, this process is poorly defined in children. We therefore measured leukocytes in 45 healthy, 18 overweight, 16 type 1 diabetic, and 8 asthmatic children at pre, end-, and 30-min postexercise (30-min intermittent or 6-min continuous). In all groups, total leukocytes, neutrophils, lymphocytes, and monocytes increased at end-exercise, but returned to baseline by 30-min postexercise, including neutrophils, previously reported to remain elevated for at least some exercise formats. This highly preserved pattern indicates the importance of the adaptive response to physical stress across multiple health conditions.
A Descriptive Study of Lower-Body Strength and Power in Overweight Adolescents
Authors: Nuzzo James L. , Cavill Michael J. , Triplett N. Travis , McBride Jeffrey M.
Published: August 2016

The primary purpose of this investigation was to provide a descriptive analysis of lower-body strength and vertical jump performance in overweight male (n = 8) and female (n = 13) adolescents. Maximal strength was tested in the leg press and isometric squat. Kinetic and kinematic variables were assessed in vertical jumps at various loads. When compared with females, males demonstrated significantly greater (p ≤ .05) absolute maximal strength in the leg press. However, when maximal strength was expressed relative to body mass, no significant difference was observed. There were no significant differences between males and females in vertical jump performance at body mass.