La rotation alternante en 3 × 8 et ses effets sur le processus d'inhibition

This experiment is based on the negative priming paradigm by using a Stroop like material (Dalrymple-Alford et Budayr, 1966) to study an inhibitory functional deficit in 3 × 8 alternating shiftworkers. The results revealed a deficit in the inhibitory mechanism when 3 × 8 and 2 × 8 ex 3 × 8 alternating shiftworkers were compared with 2 × 8 alternating shiftworkers. These results make necessary to develop further studies on the effects of the 3 × 8 alternating shiftwork on the information processing system, that focus on attentional processes.     

Manipulation of exercise to rest ratio within set duration on physical and technical outcomes during small-sided games in elite youth soccer players

Training practices for elite soccer players should take into account specific technical, tactical and physical components. As a consequence of these demands small-sided games (SSGs) have become a popular conditioning tool that replicate the demands encountered during match play. The aim of this investigation was to examine how the manipulation of exercise to rest ratio, within the same overall duration, affected both physical and technical outcomes during SSGs in elite youth soccer. Twelve elite youth soccer players participated in three variations of eight minute 6v6 SSGs. The three variations included eight minutes continuous, 2 × 4 min and 4 × 2 min. Players perceived the continuous 8 min block as the hardest (4.5 ± 1.5 AU), followed by the 2 × 4 min (3.9 ± 1.4 AU) and the 4 × 2 min (3.3 ± 1.4 AU), although no difference in mean HR or physical measures via GPS analysis between SSGs was evident. From the technical perspective, only goals scored reached significance, with post hoc analysis identifying the number of goals scored were significantly higher during the 4 × 2 min and 2 × 4 min SSGs compared to 8 min continuous block. These results show that subjective ratings of exertion differed between conditions, but only minor technical manipulations were observed by adjusting work to rest ratios, with no significant effect on physical performance.     

Dimensions of temperament and depressive symptoms: Replicating a three-way interaction

High negative emotionality (NE), low positive emotionality (PE), and low self-regulatory capacity (i.e., effortful control or EC) are related to depressive symptoms and furthermore, may moderate one another’s relations to such symptoms. Indeed, preliminary evidence suggests they may operate in a three-way interaction (Dinovo & Vasey, 2011), but the replicability of that finding remains unknown. Therefore, we tested this NE × PE × EC interaction in association with depressive symptoms in 5 independent samples. This interaction was significant in 4 of the 5 samples and a combined sample and approached significance in the fifth sample. In contrast, the NE × PE × EC interaction was unrelated to general anxious symptoms and thus may be specific to symptoms of depression. Implications, directions for future research, and limitations are discussed.     

Explanatory models of muscle performance in acromegaly patients evaluated by knee isokinetic dynamometry: Implications for rehabilitation

PurposeTo evaluate the effects of demographics and hormonal variations on knee muscle performance in patients with acromegaly and develop explanatory models of peripheral muscle function in these individuals.MethodsThis was a cross-sectional study in which 53 acromegalics and 27 healthy subjects underwent knee isokinetic dynamometry to evaluate the peak torque value for leg extension at 75°/s (PTE75) and 240°/s (PTE240). Separate multivariable linear regression models for the prediction of PTE75 and PTE240 were tested using variables commonly used as predictors in the clinical setting and other specific variables related to acromegaly.ResultsThe final prediction model for PTE75 (R² = 0.888; adjusted R² = 0.820, SE of bias = 16.2 Nm, p < 0.001) was −0.221 × growth hormone + 36.791 × sex_male = 1 − 27.407 × status_active = 1 − 0.690 × age + 148.071. The final prediction model for PTE240 (R² = 0.816; adjusted R² = 0.805, SE of bias = 8.8 Nm, p < 0.001) was −0.174 × growth hormone + 12.522 × sex_male = 1 − 0.520 × age + 98.099.ConclusionsIn acromegalics, high growth hormone levels, female gender, and older age are associated with reduced muscle strength and endurance. Additionally, active disease negatively affects peripheral muscle strength in these patients.     

Prevention programme for eating disturbances in adolescents. Is their effect on body image maintained at 30 months later?

We assessed changes in the body image of Spanish adolescents who participated in a programme aimed at preventing disordered eating, with a 30-month follow-up. 254 girls and 189 boys aged 12–14 were assigned to a control group (n = 201) or one of two possible experimental conditions: media literacy programme (ML, n = 143) and media literacy plus nutrition awareness programme (ML + NUT, n = 99). Body image was assessed with the Body Image Questionnaire (Qüestionari d’Imatge Corporal; QÜIC). Pre-test, post-test, 7- and 30-month follow-up measurements were taken. Linear model analyses were carried out with a 2 × 3 × 3 ANOVA (sex × group × phase), adjusted by the baseline level. At 30-month follow-up, ML and ML + NUT participants showed fewer body problems and more body satisfaction than the control group. There is a need for prevention programmes addressing eating and body image disturbances that involve both boys and girls.     

Effect of instructions on EMG during the bench press in trained and untrained males

Strength and rehabilitation professionals strive to emphasize certain muscles used during an exercise and it may be possible to alter muscle recruitment strategies with varying instructions. This study aimed to determine whether resistance trained and untrained males could selectively activate the pectoralis major or triceps brachii during the bench press according to various instructions. This study included 13 trained males (21.5 ± 2.9 years old, 178.7 ± 7.0 cm, 85.7 ± 10.7 kg) and 12 untrained males (20.3 ± 1.6 years old, 178.8 ± 9.4 cm, 74.6 ± 17.3 kg). Participants performed a bench press one-repetition maximum (1-RM) test, 3 uninstructed repetitions at 80% 1-RM and two more sets of three repetitions with instructions to isolate the chest or arm muscles. Electromyography (EMG) was obtained from the pectoralis major, anterior deltoid, and the long head and short head of the triceps brachii. Maximum EMG activity normalized to 1-RM for each muscle was averaged over the three repetitions for each set and compared between the uninstructed, chest-instructed and arm-instructed conditions among the groups. The trained participants had a greater 1-RM (126.2 ± 30.6 kg) than the untrained participants (61.6 ± 14.8 kg) (P < 0.01). EMG activity was not different between the groups for any of the instructions (P > 0.05). When the group data was combined, short head of the triceps activity was significantly lower in the chest instruction (80.1 ± 19.3%) when compared to the uninstructed (85.6 ± 23.3%; P = 0.01) and arm-instructed (86.0 ± 23.2; P = 0.01) conditions. It can be concluded that instructions can affect muscle activation during the bench press, and this is not dependent on training status.     

Employees’ work effort as a function of leader group prototypicality: the moderating role of team identification

The social identity model of organizational leadership (SIMOL; Hogg and van Knippenberg, 2003 was extended analyzing the degree of employees’ effort as individual outcome of leadership effectiveness. Two studies were conducted with Italian participants. Study 1 was a survey conducted with 68 employees of a medium size company. Results showed the significant two-way interaction effect of team identification × leader group prototypicality in predicting employees’ work effort. Study 2, including 124 students, was a 2 × 2 within subject design (team identification high vs. low × leader group prototypicality high vs. low) using scenarios. Results confirmed experimentally the causal relationship between such variables: subjects in condition of high team identification and high leader group prototypicality perceive leaders as more effective than the subjects in the other three conditions.     

Changes in muscular activity and lumbosacral kinematics in response to handling objects of unknown mass magnitude

The aim of this study was to evaluate the main and interaction effects of mass knowledge and mass magnitude on trunk muscular activity and lumbosacral kinematics. Eighteen participants performed symmetric box lifts of three different mass magnitudes (1.1 kg, 5 kg, 15 kg) under known and unknown mass knowledge conditions. Outcome measures were normalized peak electromyography of four trunk muscles in addition to three dimensional lumbosacral angles and acceleration. The results indicated that three out of four muscles exhibited significantly greater activity when handling unknown masses (p < .05). Meanwhile, only sagittal angular acceleration was significantly higher when handling unknown masses (115.6 ± 42.7°/s²) compared to known masses (109.3 ± 31.5°/s²). Similarly, the mass magnitude and mass knowledge interaction significantly impacted the same muscles along with the sagittal lumbosacral angle and angular acceleration (p < .05) with the greatest difference between knowledge conditions being consistently occurring under the 1.1 kg mass magnitude condition. Thus, under these conditions, it was concluded that mass magnitude has more impact than mass knowledge. However, handling objects of unknown mass magnitude could be hazardous, particularly when lifting light masses, in that they can increase mechanical burden on the lumbosacral spine due to increased muscular exertion and acceleration.     

Perfectionistic strivings and perfectionistic concerns interact to predict negative emotionality: Support for the tripartite model of perfectionism in Canadian and Chinese university students

For most individuals, perfectionistic strivings and perfectionistic concerns coexist to varying degrees. While there is agreement that within-person combinations of perfectionistic strivings and perfectionistic concerns produce meaningful “subtypes”, the number and characterization of these within-person combinations is still debated. The two most prominent person-centered perfectionism models (the tripartite model and the 2 × 2 model) offer differing characterizations of how perfectionistic strivings effects perfectionistic concerns’ relationship with psychological outcomes. According to the 2 × 2 model, perfectionistic strivings buffers against the negative effects of perfectionistic concerns. The 2 × 2 model thus claims the most deleterious within-person combination of perfectionistic strivings and perfectionistic concerns is low strivings and high concerns. In contrast, according to the tripartite model, perfectionistic strivings exacerbates the maladaptive effects of perfectionistic concerns. The tripartite model thus claims the most maladaptive within-person combination of perfectionistic strivings and perfectionistic concerns is high strivings and high concerns. The present study tested these competing claims in a group of English speaking Canadians and a group of Mandarin speaking Chinese. Results support the tripartite model of perfectionism.     

Children’s age modulates the effect of part and whole practice in motor learning

Motor skills can be learned by practicing the whole or part of a movement. In whole practice (WP), a skill is acquired by practicing the movement in its entirety, whereas in part practice (PP), a task is learned by practicing its components before combining them. However, the effectiveness of WP and PP in children is unclear. We, therefore, examined the effects of WP and PP on the learning of juggling among first-, third-, and fifth-graders. Children of each grade were pseudo-randomly assigned to the WP or PP group to learn cascade juggling in 6 days. After baseline assessments, the WP learners practiced three-beanbag juggling. The PP learners practiced one-beanbag juggling on the first 2 days, two-beanbag juggling on the following 2 days, and three-beanbag juggling on the last 2 days. Practice consisted of 40 trials each day. Skill retention and transfer trials (juggling in the opposite direction) were measured 24 h after training (number of catches). There was no significant difference between WP and PP in skill retention (WP: 1.28 ± 0.73; PP: 1.42 ± 046, p = .40) and transfer (WP: 1.31 ± 0.78; PP: 1.37 ± 0.55, p = .49). However, a time × grade × group interaction (p < .001) was observed in retention. Children of different grades received differential benefits from the WP and PP regimens. The fifth-graders learned better using WP, whereas the first- and third-graders showed better learning with PP. We discuss the three possible explanations for the results (neural maturity, explicit learning, and coordination capabilities).     

Medial prefrontal cortex infusions of bupivacaine or AP-5 block extinction of amphetamine conditioned place preference

The present experiments used reversible lesion techniques and intra-mPFC infusions of the n-methyl d-aspartate (NMDA) receptor antagonist d,l-2-amino-5-phosphonovaleric acid (AP-5) to examine the role of the mPFC in extinction of an amphetamine conditioned place preference (CPP). Following initial training and testing for an amphetamine (2 mg/kg) CPP, adult male Long–Evans rats were given extinction trials that were identical to training, except in the absence of peripheral amphetamine injections. Immediately prior to each extinction trial, rats received intra-mPFC infusions of the anesthetic drug bupivacaine (0.75% solution/0.5 μl), AP-5 (1.25, 2.5, 5.0 μg/0.5 μl), or saline. Following extinction training, rats were given a second CPP test session. Rats receiving intra-mPFC infusions of saline displayed extinction of CPP behavior. In contrast, intra-mPFC infusions of bupivacaine or AP-5 (2.5, 5.0 μg) blocked CPP extinction. The findings indicate (1) the mPFC mediates extinction of approach behavior to drug-associated environmental contexts, and (2) NMDA receptor blockade within the mPFC is sufficient to block extinction of amphetamine CPP behavior.     

Effects of domain-specific exercise load on speed and accuracy of a domain-specific perceptual-cognitive task

In the context of perceptual-cognitive expertise it is important to know whether physiological loads influence perceptual-cognitive performance. This study examined whether a handball specific physical exercise load influenced participants’ speed and accuracy in a flicker task. At rest and during a specific interval exercise of 86.5–90% HR_max, 35 participants (experts: n = 8, advanced: n = 13, novices, n = 14) performed a handball specific flicker task with two types of patterns (structured and unstructured). For reaction time, results revealed moderate effect sizes for group, with experts reacting faster than advanced and advanced reacting faster than novices, and for structure, with structured videos being performed faster than unstructured ones. A significant interaction for structure × group was also found, with experts and advanced players faster for structured videos, and novices faster for unstructured videos. For accuracy, significant main effects were found for structure with structured videos solved more accurately. A significant interaction for structure × group was revealed, with experts and advanced more accurate for structured scenes and novices more accurate for unstructured scenes. A significant interaction was also found for condition × structure; at rest, unstructured and structured scenes were performed with the same accuracy while under physical exercise, structured scenes were solved more accurately. No other interactions were found. These results were somewhat surprising given previous work in this area, although the impact of a specific physical exercise on a specific perceptual-cognitive task may be different from those tested generally.     

Acute caffeine consumption enhances the executive control of visual attention in habitual consumers

Recent work suggests that a dose of 200–400 mg caffeine can enhance both vigilance and the executive control of visual attention in individuals with low caffeine consumption profiles. The present study seeks to determine whether individuals with relatively high caffeine consumption profiles would show similar advantages. To this end, we examined the effects of four caffeine doses (0 mg, 100 mg, 200 mg, 400 mg) on low- and high-level visual attention in individuals with high consumption profiles (n = 36), in a double-blind study using a repeated measures design. Results from the Attention Network Test indicated that caffeine enhanced both vigilance and the executive control of visual attention, but only at the highest administered dose (400 mg). We demonstrate that in habitual consumers high doses of caffeine can produce beneficial changes in visual attention. These results carry implications for the theorized interactions between caffeine, adenosine and dopamine in brain regions mediating visual attention.     

Weight ratings of others: The effects of multiple target and rater features

The present study investigated factors that affect the subjective analysis of the weight of other individuals. Three hundred and thirty-three participants viewed figures varying in muscularity, adiposity, gender, and race. For each of the eighteen figures (targets), a 2 (rater gender: male, female) × 3 (rater race/ethnicity: Caucasian, African American, Hispanic) × 3 (target race/ethnicity: Caucasian, African American, Hispanic) repeated measures ANCOVA was conducted (BMI was covaried). Overall, there were few significant effects, however, for some of the figural stimuli, African American raters assigned lower weight ratings than did Caucasian and Hispanic raters. The findings offer support for further investigation of ethnic differences in weight ratings as a potential factor that might inform ethnic differences in overweight and obesity prevalence.     

Effects of anesthetic agents on socially transmitted olfactory memories in mice

Mice can learn a food preference from odor cues transmitted on the breath of a conspecific, even if the “demonstrator” is anesthetized. To our knowledge there are no studies examining the effect of anesthetizing the “observer” on development of memory for socially transmitted food preferences (STFP). In Experiment 1 we found that 2–4 month-old F2 C57Bl/6x129sv male and female mice demonstrated a STFP after a 5 min exposure to an anesthetized demonstrator mouse when tested 24 h later. In Experiment 2, observer mice anesthetized with Sagatal (60 mg/kg) prior to the “social interaction” preferentially avoided the cued food when tested 24 h later. This aversion was not due to any overt aversive effects of this dose of Sagatal because mice that ate the food and were then anesthetized, or could only smell the food for 5 min while anesthetized, showed no preference or aversion. In a third experiment we found that the Sagatal-induced aversion was not a general property of anesthesia because there were varied results produced by observer mice treated with anesthetic drugs with different mechanisms of action. Vetalar (200 mg/kg) and Rompun (10 mg/kg) treated animals ate similar amounts of cued and non-cued food at test, indicating an absence of learning. Hypnorm (0.5 ml/kg) treated animals showed a preference for the cued food whereas those treated with Hypnovel (2.5 ml/kg) showed an aversion to the cued food. These results show that the food aversion observed with Sagatal is not a general property of anesthetic agents, but appears to be restricted to those acting primarily on the GABAergic system. Thus, we have shown that under certain conditions it is possible for an anesthetized observer mouse to learn a preference or aversion of a socially-linked olfactory cue.     

Technique determinants of knee joint loads during cutting in female soccer players

The aim of this study was to investigate the relationships between technique characteristics and knee abduction moments during 90° cuts. A cross sectional design involving 26 elite and sub-elite female soccer players (mean ± SD; age: 21 ± 3.2 years, height: 1.68 ± 0.07 m, and mass: 59.1 ± 6.8 kg) was used to explore relationships between pre-determined technical factors on knee abduction moments during cutting. Three dimensional motion analyses of 90° cuts on the right leg were performed using ‘Qualisys Pro Reflex’ infrared cameras (240 Hz). Ground reaction forces were collected from two AMTI force platforms (1200 Hz) embedded into the running track to examine 2nd last and last footfalls. Pearson’s correlation coefficients, co-efficients of determination and hierarchical multiple regression were used to explore relationships between a range of technique parameters and peak knee abduction moments. Significance was set at p < .05. Hierarchical multiple regression revealed that initial knee abduction angle, lateral leg plant distance and initial lateral trunk lean could explain 67% (62% adjusted) of the variation in peak knee abduction moments (F_(1,22) = 8.869, p = .007). These findings reveal potential modifiable technical factors to lower peak knee abduction moments during cutting.     

Proprioceptive impairments associated with knee osteoarthritis are not generalized to the ankle and elbow joints

The mechanisms for proprioceptive changes associated with knee osteoarthritis (OA) remain elusive. Observations of proprioceptive changes in both affected knees and other joints imply more generalized mechanisms for proprioceptive impairment. However, evidence for a generalized effect remains controversial. This study examined whether joint repositioning proprioceptive deficits are localized to the diseased joint (knee) or generalized across other joints (elbow and ankle) in people with knee OA. Thirty individuals with right knee OA (17 female, 66 ± 7 [mean ± SD] years) of moderate/severe radiographic disease severity and 30 healthy asymptomatic controls of comparable age (17 female, 65 ± 8 years) performed active joint repositioning tests of the knee, ankle and elbow in randomised order in supine. Participants with knee OA had a larger relative error for joint repositioning of the knee than the controls (OA: 2.7 ± 2.1°, control: 1.6 ± 1.7°, p = .03). Relative error did not differ between groups for the ankle (OA: 2.2 ± 2.5°, control: 1.9 ± 1.3°, p = .50) or elbow (OA: 2.5 ± 3.3°, control: 2.9 ± 2.8°, p = .58). These results are consistent with a mechanism for proprioceptive change that is localized to the knee joint. This could be mediated by problems with mechanoreceptors, processing/relay of somatosensory input to higher centers, or joint-specific interference with cognitive processes by pain.     

Distinguishing intentions from desires: Contributions of the frontal and parietal lobes

The ability to represent desires and intentions as two distinct mental states was investigated in patients with parietal (N = 8) and frontal (N = 6) lesions and in age-matched controls (N = 7). A task was used where the satisfaction of the desire and the fulfilment of the intention did not co-vary and were manipulated in a 2 × 2 set. In two experiments we show that lesions to the frontal lobe may impair the ability to deal with desires when their outcome is not congruent with that of the intention, and that parietal damage – especially if it encompasses the left temporo-parietal junction – may cause severe difficulties in the processing of both desires and intentions. The implications of the results for the neuropsychological and the developmental literature are discussed.