Cervical range of motion and proprioception in rugby players versus non-rugby players

In this study, we examined the effects of number of years of playing rugby on neck function. Active cervical spine range of motion and proprioception were assessed in 14 non-rugby-playing but trained sportsmen (mean age 28 years, s = 7) and 46 rugby players (26 rugby forwards: mean age 26 years, s = 5; mean years played 14 years; 20 backs: mean age 24 years, s = 5; mean years played 14 years). Active cervical range of motion in flexion, extension, left and right lateral flexion, plus left and right rotation were measured using a cervical range of motion device. The ability to reposition the head in a central position with eyes closed was taken as a measure of proprioception. Results show that rugby forwards generally had the least active cervical range of motion, particularly neck extension (forwards, 43 degrees ; backs, 55 degrees ; controls, 58 degrees ), with the decrement correlating with the number of years played. In addition, repositioning was significantly worse in rugby players after neck extension than non-rugby players (6 degrees vs. 3 degrees ). The active cervical range of motion of rugby forwards is similar to that of whiplash patients, suggesting that participation in rugby can have an effect on neck range of motion that is equivalent to chronic disability. Reduced active cervical range of motion could also increase the likelihood of injury and exacerbate age-related neck problems.     

The speaker/gender effect: does the speaker’s gender matter when presenting auditory text in multimedia messages?

Current cognitive multimedia design theories provide several guidelines on how to integrate verbal and pictorial information. However, the recommendations for the design of auditory texts (narrations) are still fragmentary, especially with regard to the characteristics of the voices used. In the current paper, a fundamental question is addressed, namely, whether to use a male or a female speaker. In two experiments, learners studied dynamic visualizations on probability theory that were accompanied by narrations. The learner’s gender and the speaker’s gender served as between-subjects variables. In the first study, learners were randomly assigned to speakers of different gender. In the second study, learners could choose among different speakers. The results show that learners achieved better learning outcomes when the narration was presented by a female speaker rather than a male speaker irrespective of the learner’s gender (speaker/gender effect). Being given the choice, learners preferred female speakers, but this individual preference had no impact on learning outcomes. The results suggest augmenting purely cognitive approaches to multimedia design by social-motivational assumptions.     

How reinforcement context affects temporal production and categorization

The behavioral theory of timing assumes that timing is governed by a pacemaker whose pulses move organisms from one state to the next, and that the speed of the pacemaker covaries with the rate of reinforcement in the experimental context. The goal of the present experiments was to clarify just what constitutes that context. In Experiment 1, pigeons responded on signaled fixed-interval 20-sec and 40-sec schedules of food reinforcement that were presented randomly within sessions (alternating condition) or between sessions (isolated condition). In Experiment 2, pigeons categorized the duration of a short or a long set of intervals in the alternating or the isolated condition. Performance in both experiments was under strong control by the signals, with scalar timing between long and short sets, but no significant differences between the alternating and isolated conditions. The context of reinforcement that determines pacemaker period can thus be specific to a particular timing task and signal.