The effect of video-feedback on the learning of the tennis service by intermediate players

Effects of video-feedback on improvement of the tennis service were investigated in subjects having at least 2 years of playing experience in tennis. The experiment was carried out in an indoor tennis hall under normal training conditions. Subjects were randomly divided into three groups: a video-feedback training (VFT) group, a traditional training (TT) group and a control group, each consisting of 22 subjects. While the subjects of the control group received no training at all, subjects in both the VFT and TT groups were trained twice weekly during 5 consecutive weeks. Each training session lasted 40 min, of which 30 min was spent on actual practice in training of the service. The remaining 10 min was spent on watching, analysing and discussing video recordings of either their own service performed during the training session (VFT group), or ground strokes and volleys of top level players (TT group). Both the VFT and TT group showed significantly greater improvements in both achievement scores and form (technique) scores than did the control group. No differences, however, could be demonstrated between the VFT and TT group, indicating that the subjects of the former group did not benefit from the video-feedback they received. While form scores correlated significantly (P less than 0.001) with the velocity of the served ball, no such relation between form scores and spatial accuracy was apparent.     

Health locus of control predicts free-living, but not supervised, physical activity: a test of exercise-specific control and outcome-expectancy hypotheses

We statistically controlled fitness (1.5-mile run), outcome-expectancy values, and perceived barriers for physical activity and then compared internal health locus of control (IHLOC) with internal exercise locus of control (IEXLOC) for predicting the physical activity of college students (N = 84). Prospective observations of self-reported free-living physical activity (seven-day recall) and supervised running (time x distance) were made at 2-, 5-, and 9-week intervals. IHLOC predicted seven-day recall at Week 2 (beta = .19) and Week 5 (beta = .36) (increase in adjusted R2 ranged from .05 to .12, p less than .05). Consistent with theory, the prediction was not reproducible when generalized outcome-expectancy value rather than outcome-expectancy value for health was assessed. IHLOC was unrelated to supervised running. IEXLOC was unrelated to activity in all analyses, even though exercise-specific measures of outcome-expectancy values (beta s = .20) and perceived barriers (beta s = .27-.32) predicted both seven-day recall and supervised running (p less than .05). IHLOC also discriminated (p less than .05) high active and low active subjects when criterion groups were formed from population norms on seven-day recall (greater than or less than 280 kcal.kg-1.week-1). Results indicate that tests of decision theories that include locus of control measures specific to health or exercise must adjust for fitness, perceived barriers to physical activity, and behaviorally relevant outcome-expectancy values of physical activity when studying college students. The construct validity of exercise locus of control remains uncertain for college students.     

NCME 2007 Presidential Address: The Concordance Table: An Invitation to Misuse Test Scores

This article discusses a particular type of concordance table and the potential for test score misuse that may result from employing such a table. The concordance that is discussed is typically created between scores on different, nonequatable versions of a test that share the same or close to the same test title. These concordance tables often appear in the context of relating scores on computerized adaptive and paper‐and‐pencil versions of the same test. When such a table is presented in a complete point‐by‐point fashion, relating each reported score on the scale of the new version of the test to a reported score on the scale of the old version of the test, test score users will typically treat the table as if it represented an equating of scores between the two versions, and directly replace scores on the new version of the test by scores on the old version. This clearly represents a misuse of the test scores. Suggestions for avoiding this misuse of test scores from concordance tables are provided.