A case of behavioral heterosis in mice: quantitative and qualitative aspects of performance in a water-escape task.

Fourteen hundred and four mice from two inbred strains (Balb/c and C57BL/6), F1, F2, and backcrosses were subjected to four trials in a water-escape task and to a swimming test. Detailed analysis of mice behavior in these situations showed that the "F1 hybrid vigor" affected behavioral characters not directly related to physical vigor but of potential adaptive value. Their superiority was mainly due to more frequent adoption of an efficient behavioral tactic (direct or edge escape paths toward the exit) and more rapid progress with experience in this respect than other generations exhibited. These results clearly show that heterosis is not limited to physical vigor but may extend to behavioral and even psychological characters.     

What does the ultrasonic activity recording device measure?

Rats were observed while their behavior was being monitored by an ultrasonic activity recording device. It was found that the device yielded more counts when Ss were being more active. But very active behavior is relatively rare, so that most of the counts over a period of time are likely to result from the more frequent but less active kinds of behavior, such as grooming.     

Swimming-induced taste aversion and its prevention by a prior history of swimming

In two experiments, the evidence showed that 20 min of forced swimming by rats caused aversion to a taste solution consumed before swimming. When one of two taste solutions (sodium saccharin or sodium chloride, counterbalanced across rats) was paired with swimming and the other was not, the rats’ intakes of these two solutions showed less consumption of the former than the latter solution. Furthermore, a post-training two-bottle choice test clearly demonstrated long-lasting avoidance of the swimming-paired solution. These results imply that forced swimming acts as an unconditioned stimulus for establishing taste aversion. Preexposure to swimming opportunities before conditioning disrupts such conditioned taste aversion induced by forced swimming.     

The effect of swimming experience on acquisition and retention of swimming-based taste aversion learning in rats

Swimming endows rats with an aversion to a taste solution consumed before swimming. The present study explored whether the experience of swimming before or after the taste-swimming trials interferes with swimming-based taste aversion learning. Experiment 1 demonstrated that a single preexposure to 20 min of swimming was as effective as four or eight preexposures in causing the interference effect. Experiment 2 found that a single 5-min preexposure was enough to cause the interference effect. Experiment 3 showed that preexposure to swimming interfered with but did not completely thwart the acquisition of swimming-based taste aversion learning. Experiment 4 failed to demonstrate a reliable retroactive interference effect by swimming postexposures. With a modified procedure, however, Experiment 5 successfully demonstrated a reliable effect by four postexposures. The associative and habituation accounts of these results are discussed.     

Effects of Self-Recording and Contingent Credit on Balancing Participation Across Students

This study compared the effects of students’ (a) receiving participation credit with and without self-recording their participation and (b) self-recording participation with and without receiving credit for participation on the percentage of students functioning at four participation levels: non-participation, credit-level participation, frequent participation (slightly above credit-level), and dominant participation (2.5+ times above credit-level). Participants came from three sections of a relatively large discussion course (initially 55 students per section). Credit (with and without self-recording participation) decreased the percentage of both non-participants and dominant participants and increased the percentage of credit-level participants, thus creating greater balance in participation across students in each class. In contrast, self-recording versus non-self-recording (with and without credit) did not significantly differentiate the percentages of either non-participants or frequent participants but did differentiate the percentages of credit-level and dominant participants under the recording conditions.     

Participation profiles of current masters swimmers and their (lack of) retrospective associations with youth experiences

National athlete development models often give little consideration to the multiple ways in which adults might participate in sport (i.e., recreationally or competitively, through sampling or specialization), or their trajectories into specific patterns of adult sport participation. Using adult swimmers' current and retrospective (youth swimming) data, the purpose of this study was threefold: a) to identify profiles of masters swimmers based on participation characteristics, b) to explore demographic differences between profiles, and c) to retrospectively examine these profiles for meaningful associations with youth swimming experiences. Survey data were collected from 205 Canadian masters swimmers with previous competitive youth swimming experience (M age = 44.4, range = 18–85; 60% women, 40% men). Two-step clustering analysis of masters' current swimming participation resulted in three distinct profiles: 1) “low-competitive specializers,” 2) “high-competitive specializers,” and 3) “samplers.” These profiles were not significantly associated with any demographic variables in adulthood, nor did they differ in terms of youth swimming experiences and time to transition into masters swimming. The remarkable homogeneity of social-demographic variables suggests that further work is needed to make masters swimming more inviting to diverse adult populations. Retrospective data revealed disengagement and later re-engagement in swimming that was consistent across masters profiles. Implications of these findings for coaches and programmers, as well as the need to account for adults' potentially complex re-entries into sport after time away, are discussed.     

Characteristics and Effects of the Co-parenting Alliance between Incarcerated Parents and Child Caregivers

We examined co-parenting alliance based on information provided by 57 incarcerated parents and their corresponding child caregivers who took part in the Messages Project, in which incarcerated parents video recorded greetings to children that were then mailed home. We assessed perceptions of co-parenting alliance, measured by the Parenting Alliance Measure, and levels of child contact from both parents and caregivers. We also observed expressions of positive and negative attitudes that prisoners expressed regarding the home caregiver during the video recording. Incarcerated parents reported more frequent phone contact with children and more frequent letter-writing to children than did home caregivers. Incarcerated parents likewise reported higher levels of co-parenting alliance with the home caregiver in comparison to the assessment of co-parenting alliance reported by the home caregiver. Among children observing the video recorded message, a more positive co-parenting alliance between their parent and home caregiver was associated with increased positive mood. More frequent displays of negative attitudes toward caregivers during the recordings were associated with more negative mood indicators among children. Results suggest the importance of a strong co-parenting alliance between incarcerated parents and home caregivers, but imply that incarcerated parents may have a more optimistic view of their connection home than is the case for collaborating caregivers.     

Parenting and Children's Intrinsic Motivation in Age Group Swimming

The parenting correlates of children's intrinsic motivation in swimming were examined. Mothers and fathers of 135 9- to 12-year-old competitive swimmers completed questionnaires about their child's swimming ability and about their current parenting practices. Children provided information about their swimming motivations. Results showed that children's ability in swimming (based on both mother and father ratings and on objective swimming performance) was positively associated with children's reports of intrinsic motivation. After controlling for child ability, mothers', but not fathers', parenting practices predicted children's intrinsic motivation: maternal directiveness was negatively associated with intrinsic motivation and maternal performance goals showed a positive association. Curvilinear effects were significant as well, with the highest level of intrinsic motivation found among children whose mothers showed intermediate values on performance goals and either high or low levels of directiveness.     

High level swimming performance and its relation to non-specific parameters: a cross-sectional study on maximum handgrip isometric strength

The relationship between handgrip isometric strength and swimming performance was assessed in the four competitive swimming strokes in swimmers of different age groups and of both sexes. 78 national-level Portuguese swimmers (39 males, 39 females) were selected for this study. Grip strength, previously used as a marker of overall strength to predict future swimming performance, was measured using a hand dynamometer. The best competitive time at 100 and 200 m in all four swimming strokes were converted into 2010 FINA points. Non-parametric tests were used to evaluate differences between groups. Pearson product-moment correlations were computed to verify the association between variables. Handgrip maximum isometric strength was significantly correlated with swimming performance, particularly among female swimmers. Among female age group swimmers, the relationship between handgrip and 100-m freestyle was significant. Handgrip isometric strength seems to be related to swimming performance, especially to 100-m freestyle and in female swimmers. For all other distances and strokes, technique and training probably are more influential than semi-hereditary strength markers such as grip strength.     

Speed modulation in swimming frogs

Swimming movements of 7 European green frogs (Rana esculenta) were studied, starting from the detailed analysis of the speed and timing of the propulsive, glide, and recovery phases of their intermittent swimming behavior. First, the authors identified the spatiotemporal factors used by the frogs to modulate their swimming behavior. None of the gait variables correlated strongly with average swimming speed, and no significant correlations were found between variables belonging to different phases. There did not seem to be an obvious control strategy. Instantaneous speeds at the transition of the different phases all increased significantly with average speed, however. The strong correlation between maximal speed at the end of propulsion and the speed averaged over a cycle might reflect the dominance of the propulsive phase in the determination of the overall swimming speed. The modulation of swimming speed thus seemed largely comparable with the regulation of jumping distance. That finding was confirmed in a mathematical model, in which the positive correlations between both glide and recovery speeds, on the one hand, and average speed, on the other, were shown to be only mathematical consequences of the strong impact of the propulsive phase on overall swimming performance. That finding suggests that the correlations did not result from an active control strategy.     

Speed Modulation in Swimming Frogs

Swimming movements of 7 European green frogs (Rana esculenta) were studied, starting from the detailed analysis of the speed and timing of the propulsive, glide, and recovery phases of their intermittent swimming behavior. First, the authors identified the spatiotemporal factors used by the frogs to modulate their swimming behavior. None of the gait variables correlated strongly with average swimming speed, and no significant correlations were found between variables belonging to different phases. There did not seem to be an obvious control strategy. Instantaneous speeds at the transition of the different phases all increased significantly with average speed, however. The strong correlation between maximal speed at the end of propulsion and the speed averaged over a cycle might reflect the dominance of the propulsive phase in the determination of the overall swimming speed. The modulation of swimming speed thus seemed largely comparable with the regulation of jumping distance. That finding was confirmed in a mathematical model, in which the positive correlations between both glide and recovery speeds, on the one hand, and average speed, on the other, were shown to be only mathematical consequences of the strong impact of the propulsive phase on overall swimming performance. That finding suggests that the correlations did not result from an active control strategy.     

Swimming as an accretive practice in healthy blue space

Cultural geographers are increasingly interested in research on water and water-based practices as sites of study. Parallel literatures on therapeutic landscapes, especially emergent work on healthy blue space, have also begun to explore emotional geographies. This paper is an empirical study of outdoor swimming in Ireland with a specific focus on health and wellbeing. A key aim is to uncover evidence on how specific blue places and practices enable health. The idea of a continuum is utilised to link theory and practice and connect rather than divide affect, feeling and emotion. This is articulated through a set of embodied experiential practices that proposed swimming as a process of therapeutic accretion. Both personal and shared histories are used to identify the importance of both swimming practices and places to show how therapeutic accretions emerge to build healthy resilience. Additional insights suggest aspects of embodied health that are enhanced by outdoor swimming, especially in relation to bodies perceived to be inactive due to age, illness or disability. While the risks are not ignored, the need to better value outdoor swimming in cooler climates for public health is proposed, suggesting new directions for research on outdoor swimming to simultaneously capture active and passive embodied and emotional experiences within blue space.     

Quantification of upper limb kinetic asymmetries in front crawl swimming

This study aimed at quantifying upper limb kinetic asymmetries in maximal front crawl swimming and to examine if these asymmetries would affect the contribution of force exertion to swimming performance. Eighteen high level male swimmers with unilateral breathing patterns and sprint or middle distance specialists, volunteered as participants. A load-cell was used to quantify the forces exerted in water by completing a 30 s maximal front crawl tethered swimming test and a maximal 50 m free swimming was considered as a performance criterion. Individual force–time curves were obtained to calculate the mean and maximum forces per cycle, for each upper limb. Following, symmetry index was estimated and breathing laterality identified by questionnaire. Lastly, the pattern of asymmetries along the test was estimated for each upper limb using linear regression of peak forces per cycle. Asymmetrical force exertion was observed in the majority of the swimmers (66.7%), with a total correspondence of breathing laterality opposite to the side of the force asymmetry. Forces exerted by the dominant upper limb presented a higher decrease than from the non-dominant. Very strong associations were found between exerted forces and swimming performance, when controlling the isolated effect of symmetry index. Results point that force asymmetries occur in the majority of the swimmers, and that these asymmetries are most evident in the first cycles of a maximum bout. Symmetry index stood up as an influencing factor on the contribution of tethered forces over swimming performance. Thus, to some extent, a certain degree of asymmetry is not critical for short swimming performance.     

Taste Aversion Learning Based on Swimming and Lithium Chloride Injection in Rats: Implications From Cross-familiarization Tests and Stimulus Selectivity1

In rats, swimming causes avoidance of the taste solution consumed immediately before the swimming. Several lines of research have shown that this taste avoidance reflects Pavlovian conditioned aversion based on correlations between the taste and swimming-induced nausea. The present research compared swimming-based taste aversion learning (TAL) with conventional TAL based on nausea-inducing lithium chloride (LiCl). By exploiting cross-familiarization techniques, Experiments 1A and 1B suggested that different physiological states are induced by swimming and LiCl. This claim was supported by Experiment 2, which reports stimulus selectivity in saccharin and sucrose aversions based on swimming and LiCl.     

Aggressive behavior during the breeding season of adult female rhesus monkeys (Macaca mulatta)

The aggressive behavior of eight adult female rhesus living in a captive social group was studied prior to and during a breeding season extended by vasectomizing all the adult males in the group. Female reproductive status was ascertained by: recording all adult female-adult male copulations; detecting menstruation by vaginal swabbing; and analyzing serum progesterone levels by radioimmunoassay. Females showed more non-contact aggression during the breeding season, but wounding did not increase. Individual cycling females directed more frequent aggression to: particular adult males subordinate to them, subordinate females also in estrus, and (in a few cases) juveniles and infants.     

Long lasting increase in nociceptive threshold induced in mice by forced swimming: involvement of an endorphinergic mechanism

Mice submitted to forced swimming session(s) displayed a long lasting modification in their nociceptive threshold, assessed through their jump latency from a hot plate (55 degrees C). Thus two forced swimming sessions (6 min each, 8h apart), in water at 33 degrees C, increased by about 50% the jump latency when the hot plate test was performed 14 hours, 3 days or 6 days thereafter. The water temperature (16 degrees C vs 33 degrees C) had no critical influence in this respect. To be clearly effective (at 33 degrees C) the swimming session had to be performed twice (when performed only once it was irregularly effective); it apparently culminated for a 6 min duration, since its effectiveness was not significantly increased by extending the swimming time to 12 min or 18 min. Performing 2 forced swimming sessions (6 min each, 8h apart), 5 consecutive days, resulted in a suppression of the increase in jump latency in the hot plate test. The two forced swimming episodes-induced analgesia was prevented by the s.c. administration of diazepam (from 0.125 mg/kg) or morphine (from 5 mg/kg) or scopolamine (1 mg/kg) before each forced swimming episode. Morphine (7.5 mg/kg) was uneffective to prevent the induction of two forced swimming episodes-induced analgesia when it was administered immediately after each forced swimming session. Finally this analgesia was dose dependently reversed by naloxone (ID(50) = 0.14 mg/kg, s.c., 30 min before the hot plate test). It is hypothesized that the handling of mice immediately before the hot plate test induces the remembrance of the stress induced by previous forced swimming episodes, triggering a fear reaction which increases the nociceptive threshold.     

Effect of increasing energy cost on arm coordination in elite sprint swimmers

The purpose of this study was to analyze the changes in stroke parameters, motor organization and swimming efficiency with increasing energy cost in aquatic locomotion. Seven elite sprint swimmers performed a 6×300-m incremental swimming test. Stroke parameters (speed, stroke rate and stroke length), motor organization (arm stroke phases and arm coordination index), swimming efficiency (swimming speed squared and hand speed squared) and stroke index were calculated from aerial and underwater side-view cameras. The energy cost of locomotion was assessed by measuring oxygen consumption and blood lactate. Results showed that the increase in energy cost of locomotion was correlated to an increase in the index of coordination and stroke rate, and a decrease in stroke length (p<.05). Furthermore, indicators of swimming efficiency and stroke index did not change significantly with the speed increments (p<.05), indicating that swimmers did not decrease their efficiency despite the increase in energy cost. In parallel, an increase in the index of coordination IdC and stroke rate were observed, along with a decrease in stroke length, stroke index and hand speed squared with each increment, revealing an adaptation to the fatigue within the 300m.     

Speed during training and anthropometric measures in relation to race performance by male and female open-water ultra-endurance swimmers

The relationship of anthropometric and training characteristics with race time were investigated in 39 male and 24 female open-water ultra-endurance swimmers in a 26.4 km open-water ultra-swim, using bi- and multivariate analyses. For the men, body height, Body Mass Index, length of arm, and swimming speed during training were related to race time in the bivariate analysis. For the women, swimming speed during training was associated with performance in the bivariate analysis. In the multivariate analysis for the men, Body Mass Index and swimming speed during training were related to race time.     

Use of an Antecedent Intervention to Decrease Vocal Stereotypy of a Student With Autism in the General Education Classroom

This study examined the use of an antecedent-based intervention to reduce the vocal stereotypy of a student diagnosed with Autism within the general education classroom. The student displayed frequent nonfunctional speech and disruptive vocal sounds. An antecedent-based intervention, involving the use of qualitatively different cards—to cue the student when it was appropriate or inappropriate to engage in vocal stereotypy—was designed and implemented. An adaptive alternating treatment design was utilized and conditions were randomized and counterbalanced across treatment sessions. Data on vocal stereotypy were collected using partial interval recording. The results indicated the participant was successful in discriminating between cues and decreased stereotypy during intervention compared to baseline conditions. Similar findings were found when the intervention was implemented across a second school setting.     

The importance of reflection and evaluation processes in daily training sessions for progression toward elite level swimming performance

Self-regulated learning (SRL) involves self-directed metacognitive subprocesses and motivational beliefs that facilitate more effective and efficient learning. We investigated whether youth swimmers who are on track to becoming elite swimmers apply SRL subprocesses more frequently in their daily training sessions compared with swimmers who are not on this track. Insights into swimmers’ use of training-centered SRL could advance understanding about underlying individual characteristics that contribute to optimal engagement in daily training and, consequently, progression toward elite level swimming performance. We collected data on training-centered SRL subprocesses (evaluation, planning, reflection, speaking up, effort and self-efficacy) and performance data for 157 youth swimmers aged 12–21 years (73 males and 84 females). The results of a multivariate analysis of covariance revealed significantly higher scores for reflection processes during training for high-performing swimmers but lower scores for effort compared with lower-performing swimmers (p < 0.05). A closer examination of the high-performing group showed that those demonstrating greater improvement during a season scored significantly higher for evaluation processes after training compared with those evidencing less improvement during a season (p < 0.05). Significant between-group differences in SRL subprocesses remained after adjusting for differences in weekly training hours. Youth swimmers on track to becoming elite swimmers are characterized by more frequent use of reflection processes during training and evaluation processes after training, which suggests that these swimmers’ learning and training processes are more effective and efficient. Ultimately, this could contribute to a higher quality of daily training, which may result in greater improvements during a season, higher performance levels, and a greater chance of reaching the level of elite swimming performance.