Electromyographic analysis of thigh muscles during track cycling on a velodrome

We aimed to investigate neuromuscular activation of thigh muscles during track cycling at various speeds. Eight male competitive cyclists volunteered to participate in this study. Surface electromyography of the vastus lateralis, biceps femoris and adductor magnus muscles of the bilateral legs was recorded during track cycling on velodromes with a 250-m track. The participants were instructed to maintain three different lap times: 20, 18 and 16 s. The average rectified value (ARV) was calculated from the sampled surface electromyography. Significantly higher ARVs were observed in the right compared to left leg for the biceps femoris muscle during both straight and curved sections at 18- and 16-s lap times (P < 0.05). In the biceps femoris muscle, significant changes in ARVs during the recovery phase with an increase in speed were seen in the right leg only (P < 0.05). There were no significant differences in ARVs between the straight and curved sections for all three muscles (P > 0.05). From our findings, it was suggested that during track cycling on a velodrome the laterality of the biceps femoris muscle activity is a key strategy to regulate the speed, and fixed neuromuscular strategies are adopted between straight and curved sections for thigh muscles.     

Spousal Presence Modulates Salivary α-Amylase Responses to Infant Cry in Mothers With High Attachment Insecurity

SYNOPSIS

Objective: Infant cry, a major stressor for caregivers, is one of the leading triggers of child abuse. The present study examined the effects of spousal support, spousal presence, and the possible moderating effect of attachment insecurity on individuals’ subjective and physiological responses to infant cry. Design: Thirty-one healthy mothers (M age = 36 years) and their spouses participated in an infant crying paradigm, where mothers were tasked to listen to infant cries under three conditions: (1) alone, (2) in the same room as partner, without physical contact, and (3) in the same room as partner, with hand-holding. Attachment was determined using the Experiences in Close Relationship Questionnaire, and physiological response was ascertained from concentration of salivary α-amylase (sAA). After each cry sound, sAA level and subjective responses to infant cry were assessed. Results: Multilevel regression analyses revealed that trait attachment-anxiety moderated the effect of spousal presence on sAA. Specifically, mothers with high attachment-anxiety showed reduced sAA when their spouse was present, which indicates that spousal support is effective for mothers with high attachment-anxiety. Conclusions: Findings from this study translate to promising clinical applications for the management of parenting stress from infant cry.     

The effect of acceleration signal processing for head impact numeric simulations

Brain injury research in sport employs a variety of physical models equipped with accelerometers. These acceleration signals are commonly processed using filters. The purpose of this research was to determine the effect of applying filters with different cutoff frequencies to the acceleration signals used as input for finite element modeling of the brain. Signals were generated from reconstructions of concussion events from American football and ice hockey in the laboratory using a Hybrid III headform. The resulting acceleration signals were used as input for the University College Dublin Brain Trauma Model after being processed with filters. The results indicated that using a filter with a cutoff of 300 Hz or higher had little effect on the resulting strain measures. In some cases there was some effect of the filters on the peak linear (8–30g) and rotational measures (1000–4000 rad/s²), but little effect on the finite element strain result (approximately 2–6 %). The short duration and high magnitude accelerations, such as the puck impact, were most affected by the cutoff frequency of different filters.     

A comparison of the capacity of ice hockey goaltender masks for the protection from puck impacts

Goaltenders in ice hockey are the only players that are on the ice for the entire game. Their position exposes them to impacts from collisions with other players, falls to the ice, and puck impacts. In competitive ice hockey leagues, head injuries resulting from puck impacts have been reported with some cases resulting in ending the player’s career. Considerable research has been conducted to assess the performance of hockey helmets; however, few have assessed the performance of goaltenders’ masks. The purpose of this study was to compare the capacity of four goaltenders’ masks for the protection from puck impact as measured by head acceleration and peak force. A Hybrid III headform was fitted with four different goaltender masks and impacted with a hockey puck in three locations at 25 m/s. The masks were found to vary in the level of protection they offered as the mask with the thickest liner resulted in lower forces than the thinnest mask for side impacts; however, the thinnest mask resulted in the lowest force for front impacts. Despite performance differences at specific locations, no one mask proved to be superior as peak acceleration and peak force values did not exceed the thresholds necessary for concussion.     

Gender Effects in Assessment of Economic Knowledge and Understanding: Differences Among Undergraduate Business and Economics Students in Germany,Japan, and the United States

Gender effects in large-scale assessments have become an increasingly important research area within and across countries. Yet few studies have linked differences in assessment results of male and female students in higher education to construct-relevant features of the target construct. This paper examines gender effects on students’ economic content knowledge with a focus on construct-relevant explanations. Moreover, we compare gender effects cross-nationally between Germany, Japan, and the United States. To assess economic content knowledge of higher education students, we used translated, adapted, and validated versions of the Test of Understanding in College Economics (TUCE, 4th ed.), an instrument that is commonly used internationally. We found gender effects on test scores in all three countries; effects were larger in Germany and the United States than in Japan. Gender effects were generally more pronounced on the numeracy subscale than on the literacy subscale, that is, male students had a greater edge over female students when items required calculations. In our conclusion, we discuss how numeracy and literacy items may tap different abilities.     

Analysis of speed accuracy using video analysis software

Determining an athlete’s speed from broadcast video is a common practice in sport. Many software packages that perform data extraction from video files are expensive; however, open source software is also available, but lacks published validation for speed measurements. The purpose of this research was to examine the error of speed measurements extracted from video during an ice hockey skating exercise using open source software. The subject completed four exercises, at two speeds recorded by broadcast cameras set at five angles. The speeds from the broadcast cameras were compared to speeds calculated from a high-speed camera placed orthogonally to the exercise. Speeds from the broadcast cameras correlated well with the high-speed video for motion more than 12 m away from the broadcast camera. When comparing all the measured speeds, no significant difference was found between the speeds calculated by the high-speed camera (slow: 4.46 m/s ± 0.2; fast: 7.2 m/s ± 0.7) and the speed calculated from the broadcast cameras (slow: 4.50 m/s ± 0.4; fast: 7.34 m/s ± 0.6) (p > 0.05). The open source method was found to be less accurate when the athlete was close to (within 12 m of camera position) or moving directly toward the broadcast cameras.     

Event-specific impact test protocol for ice hockey goaltender masks

ABSTRACT

Goaltenders in the sport of ice hockey are at high risk for concussions from falls to the ice, player collisions and puck impacts. However, current methods used to certify helmets only consider head accelerations for drop tests which may not describe all common injury mechanisms relating to concussion. The purpose of this study was to describe the characteristics of 3 events associated with concussions for ice hockey goaltenders. A helmeted medium National Operating Committee on Standards for Athletic Equipment (NOCSAE) headform was impacted under conditions representing 3 injury events. Three impact locations’ velocities were selected for each event based on video analysis of real-world concussive events. Peak resultant linear acceleration, rotational acceleration and rotational velocity of the headform were measured. The University College Dublin Brain Trauma Model (UCDBTM) was used to calculate maximum principal strain (MPS) and von Mises stress in the cerebrum. Each impact event produced a unique dynamic response and brain stress and strain values. This demonstrates that a single impact event (i.e. falls) cannot adequately describe all impact events. As a result, impact protocols which assess multiple impact events such as the protocol described in this study should be used to evaluate ice hockey goaltender masks.     

Educational productivity and rorschach location responses of preschool Japanese and American children

This study compared Rorschach protocols of Japanese five- and six-year-olds with norms of CA comparable Americans, as reported by Exner. Japanese location responses profiles were characteristic of rapid mental development: fewer whole responses, and a higher proportion of major and minor details. Moreover, the Japanese provided more responses and over a greater breadth of content categories. Relatively small differences obtained with respect to developmental quality (DQ), which measures complexity and flexibility employed in responding to blots; Japanese scores on form quality (FQ), associated with conventionality, were significantly lower. However, Exner's FQ scoring format is based on conventionality of Americans' responses; the lower Japanese indices on this measure may be associated with cultural factors that influence perceptual responses and that may affect cross-cultural understandings.     

A Possible Mechanism of Stress-Relieving Effects of Spousal Presence and Implications for Future Infant Cry Research

SYNOPSIS

Infant crying is one of the parenting stressors, and our research suggests that the presence of spouse has a stress relieving effect in mothers with high attachment anxiety. Its mechanism is, however, still unclear. Here we will discuss the possible mechanism again corresponding to the commentaries. First, we briefly review the difficulties that individuals with high attachment insecurity face in parenting situation and discuss the possible cause why spousal presence smooth out the difficulties focusing on the role of oxytocin. Second, we point out potential issues in parenting research which presuppose the linear relationship between parental physiological or neural response, and parenting behavior. Finally, we discuss the future parenting research such as children with developmental disability or fathers that has gained less attention in previous research.