Effect of concurrent visual feedback on acquisition of a weightlifting skill

Practice in front of a mirror is a common procedure for activities such as dance, gymnastics, and other sports. The purpose of this study was to examine the effect that performing with concurrent visual feedback from a mirror had on the acquisition of the power clean movement. 18 college-age males who had no prior experience with the power clean movement served as subjects who were assigned to one of two groups. One group had use of a mirror during the practice trials and the other practiced without the mirror. All subjects viewed an instructional videotape and had practice trials. All subjects were evaluated for proper technique on a pretest, a posttest without the mirror, and a posttest with the mirror. Analysis showed a significant difference between pre- and posttest performances for both groups and a significant difference between groups on the posttest performances with the mirror. Evidently the videotaped instruction was sufficient to allow both groups to improve in performance of the power clean. Differences in posttest performances with the mirror reflected the type of feedback (with or without the mirror) available during training.     

Objective measurement of pain in the wrist: analyses of basic factors for normative data and a case study

A plate-pushing task was used to measure endogenous pain in the wrist from different loci. Practical application in rehabilitation seems reasonable.     

Visual Elaboration Scale as a measure of imagery

We studied the correlation of one measure of imagery ability, the Visual Elaboration Scale, with two others, absorption of image and effort required to form a mental image. Significant correlations were obtained between the Visual Elaboration Scale and the other scales, with the exception of Absorption for women.     

Personality characteristics of individuals with chronic rheumatoid arthritis

MMPI profiles of 22 chronic arthritic patients were compared to 22 control pain (nonorganic) patients. While elevations were noted in the HS, D, and Hy scales for the rheumatoid patients, the over-all profiles differed from controls on the PA scale.     

Effect of reaction time condition on EMG activities of the biceps brachii muscle in elbow flexion and forearm supination

Under simple- and choice-RT conditions, the biceps brachii muscle was examined in 8 healthy male subjects to determine how the temporal and spatial characteristics of elbow flexion and forearm supination differed at the initial phase of EMG activity and whether preparation or the presence of response uncertainty influenced the EMG outputs of the two movements. In the simple-RT condition, RT of supination was significantly faster than that of flexion but EMG activity of supination was less than that of flexion. In contrast, in the choice-RT condition, RT of flexion was significantly faster than that of supination but EMG activity of flexion was significantly reduced compared to supination. These findings indicate that advanced preparation or motor set facilitates the differentiation of RTs and EMG activities of the response movements and that response uncertainty causes a significant change in the temporal and spatial specificity of both elbow flexion and forearm supination.     

Sample size determinations for the two rater kappa statistic

This paper gives a method for determining a sample size that will achieve a prespecified bound on confidence interval width for the interrater agreement measure,. The same results can be used when a prespecified power is desired for testing hypotheses about the value of kappa. An example from the literature is used to illustrate the methods proposed here.