The aim of this study was to analyse the adjustments in technique made by a basketball player when shooting against an opponent. The subjects used consisted of 10 professional basketball players of the Spanish First Division League. Threedimensional motion analysis based on video recordings (50 Hz) was used to obtain the kinematic characteristics of basketball jump shots with and without an opponent. It was found that when performing against an opponent the release angle of the ball increased, the¯ight time was reduced and postural adjustments as determined by the angles at the knee and shoulder increased, all signi® cantly. There were several other non-signi® cant diVerences that helped to interpret the changes in technique imposed by the presence of an opponent. It was suggested that when shooting with an opponent, players attempted to release the ball more quickly and from a greater height. This strategy will lessen the chance of the opponent intercepting the ball. It was concluded that the diVerences noted in the technical execution of the skill had implications for practice. It was suggested that training would bene® t from practice with an opponent for at least some of the time to condition players to the demands which they were more likely to meet in the game situation.

We have compared the effects of different 12-week exercise programs on simple and choice reaction and movement times in persons 61 to 84 years old. One hundred thirty-eight volunteers were randomized to either a control group, a two-day exercise group (two 60-min sessions a week of aerobic exercises), or a two-day physical plus cognitive exercise group (two 60-min sessions a week of aerobic and cognitive exercises). At follow-up, the aerobic and cognitive exercise program was found to have resulted in significant positive effects. Improvements were found in the two-day physical plus cognitive exercise group in all of the reaction parameters, particularly improvement in choice reaction time, which is used in most daily activities. Our results suggest that to improve reaction time values, it is advisable to include cognitive features into a physical exercise routine.

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In the present study, effects of using precues of the goalkeeper's movements during a penalty kick on the penalty taker's response time and rate of success when selecting the points at which shots were taken were evaluated. 20 male players included 10 expert players (M=25.7 yr., SD=4.2 yr.) and 10 novices (M=22.1 yr., SD=2.5 yr.), whose response time, decision making, and foveal vision in a simulated penalty kick task were evaluated. Analysis showed greater decrease in response time for the expert group (102 msec.) than for the novice one (47 msec.). Mean response time was 172 msec. for experts and 189 msec. for novices. The rate of success (i.e., shooting at the side opposite to the goalkeeper's movement) increased from an initial rate of 58% for both groups to 91.3% in the Expert group and 90.7% in the Novice group. Anticipation of both groups improved with explicit knowledge of precues.

Recently, doubts have begun to surface about the emphasis that for years has been given to the variable knowledge of results in motor learning, and a view has been expressed that information on how an action has been made (knowledge of performance) may be of more use. This study compared the two types of information in learning a volleyball serve by eight subjects, who were given the two kinds of feedback at various points in the process. Analysis seems to show that knowledge of performance tends to be more effective for learning and that there may be interference across information if knowledge of results is provided after knowledge of performance.