Static posturography provides an objective assessment of postural control by characterizing the body sway during upright standing. The center of pressure (COP) signal is recorded by a force platform, and it is analyzed by means of many different models and techniques. Most of the parameters calculated according to these different approaches are affected by relevant intra- and intersubject variability or do not have a clear physiological interpretation. Traditional approaches decompose the COP signal into anteroposterior and mediolateral time series, corresponding to ankle plantar/dorsiflexion and hip adduction/abduction, respectively. In this study we hypothesized that COP signals show inherent rotational characteristics. To verify our hypothesis we applied the rotary spectra analysis to the two-dimensional COP signal to decompose it into clockwise and counterclockwise rotational components. We demonstrated the presence of rotational components in the COP signal of healthy subjects, providing a reference data set of the spectral characteristics of these components.
Valentina Agostini, Emma Chiaramello and Marco Knaflitz
Dana K. Voelker and Justine J. Reel
Figure skaters are evaluated on the execution of challenging technical skills as well as how those skills are packaged with other performance components, including costume, music, choreography, and physical appearance ( Cummins, 2007 ). Male and female skaters report experiencing pressure from a
Susan Lagaert, Mieke Van Houtte and Henk Roose
; Messner & Musto, 2014 ; Qvortrup et al., 2009 ), we evaluate three possible mechanisms behind the gendering of taste that receive increasing attention in sports sociology: gender identity, pressure to conform to gender stereotypes and gender role attitudes ( Boiché, Plaza, Chalabaev, Guillet
Thiago Correa Porto Gonçalves, Atila Alexandre Trapé, Jhennyfer Aline Lima Rodrigues, Simone Sakagute Tavares and Carlos Roberto Bueno Junior
of multicomponent training resulted in an increase in NO and antioxidant capacity and a decrease in blood pressure (BP) in women aged between 50 and 80 years; however, these results seem to be associated with the nitric oxide synthase 3 (NOS3) genotypes and haplotypes ( Trapé et al., 2017
Yumeng Li, Melissa A. Mache and Teri A. Todd
common feature of ASD, 12 could result in activity avoidance. Most of the studies surrounding the postural stability have utilized traditional linear analyses of center of pressure (COP) and found that children with ASD demonstrated greater sway displacements, 13 , 14 sway areas, 8 , 9 SDs of sway
This study investigated the effect of psychological pressure on spinal reflex excitability. Thirteen participants performed a balancing task by standing on a balance disk with one foot. After six practice trials, they performed one nonpressure and one pressure trial involving a performance-contingent cash reward or punishment. Stress responses were successfully induced; state anxiety, mental effort, and heart rates all increased under pressure. Soleus Hoffmann reflex amplitude in the pressure trial was significantly smaller than in the nonpressure trial. This modification of spinal reflexes may be caused by presynaptic inhibition under the control of higher central nerve excitation under pressure. This change did not prevent 12 of the 13 participants from successfully completing the postural control task under pressure. These results suggest that Hoffmann reflex inhibition would contribute to optimal postural control under stressful situations.
Rob Gray and Jonathan Allsop
How is performance under pressure influenced by the history of events that precede it, and how does the pressure outcome influence the series of events that follow? A baseball batting simulation was used with college players to investigate these questions. In Experiment 1, the difficulty of the simulation was first adaptively adjusted to equate performance level. Batters next completed 20 at-bats used to classify them into one of three performance groups (normal, cold streak, or hot streak) followed by a one at-bat pressure condition. Finally, performance was evaluated over a period of 20 postpressure at-bats. In Experiment 2, a series of secondary tasks were added to assess attentional focus. In both experiments, whether batters succeeded or failed under pressure was significantly related to their performance history immediately before the pressure event, with the normal group having the poorest pressure performance. Performance postpressure was significantly related to both the pressure outcome and prepressure performance. These performance effects were related to changes in the batter’s attentional focus as shown by changes in secondary task accuracy.
Christopher Mesagno, Jack T. Harvey and Christopher M. Janelle
Whether self-presentation is involved in the choking process remains unknown. The purpose of the current study was to determine the role of self-presentation concerns on the frequency of choking within the context of a recently proposed self-presentation model. Experienced field hockey players (N = 45) were randomly assigned to one of five groups (i.e., performance-contingent monetary incentive, video camera placebo, video camera self-presentation, audience, or combined pressure), before taking penalty strokes in low- and high-pressure phases. Results indicated that groups exposed to self-presentation manipulations experienced choking, whereas those receiving motivational pressure treatments decreased anxiety and increased performance under pressure. Furthermore, cognitive state anxiety mediated the relationship between the self-presentation group and performance. These findings provide quantitative support for the proposed self-presentation model of choking, while also holding implications for anxiety manipulations in future sport psychology research.
Brian Klucinec, Craig Denegar and Rizwan Mahmood
During the administration of therapeutic ultrasound, the amount of pressure at the sound head-tissue interface may affect the physiological response to and the outcome of treatment. Speed of sonification; size of the treatment area; frequency, intensity, and type of wave; and coupling media are important parameters in providing the patient with an appropriate ultrasound treatment. Pressure variations affect ultrasound transmissivity, yet pressure differences have been virtually unexplored. The purpose of this study was to assess the effects of sound head pressure on acoustic transmissivity. Three trials were conducted whereby pig tissue was subjected to increased sound head pressures using manufactured weights. The weights were added in 100 g increments, starting with 200 g and finishing with 1,400 g. Increased pressure on the transmitting transducer did affect acoustic transmissivity; acoustic energy transmission was increased from 200 g (0.44 lb) up to and optimally at 600 g (1.32 lb). However, there was decreased transmissivity from 700 to 1, 400 g (1.54 to 3.00 lb).
Frank A. Treiber, Francis McCaffrey, William B. Strong, Harry Davis and Tom Baranowski
This study compared blood pressure and heart rate measurements provided by the Quinton 410 automated exercise monitor with simultaneous auscultatory and electrocardiograph readings during rest, postural change, immediately after each treadmill exercise workload, and during active recovery in a sample of young children (mean age 7.9 yrs). The Quinton 410 provided highly accurate heart rates under all conditions (average mean difference <1.0 bpm). The Quinton systolic readings correlated well with and were similar to auscultation across conditions except for the initial treadmill workload. Slightly weaker relationships were observed between the Quinton and K4 diastolic comparisons. Compared with K4 auscultatory readings, the Quinton 410 provided slightly lower diastolic pressures across conditions (average mean difference = 3.1 mmHg). These findings provide preliminary evidence that for group comparisons with children, the Quinton 410 provides acceptable blood pressure estimates resulting from a variety of events, including exercise.