Biomedical subjects

I M Franks

Publications and source records attributed to I M Franks.

9 recordsLinked to original sources

PubMed1991

The effects of changing movement velocity and complexity on response preparation: evidence from latency, kinematic, and EMG measures.

If movement control is afforded through the advance planning, or preprogramming, of upcoming actions, then one of the behavioral outcomes should be an increase in reaction time (RT) as the movement becomes more complex. In some situations, however, RT does not increase across levels of complexity, rather it remains invariant. In these cases, on-line preparation is typically inferred. That is, the sequence is said to be prepared in parts throughout the movement, as opposed to entirely beforehand. Given that there is some planning occurring during the sequence, then evidence of this process should be apparent within the movement itself. Three such dependent variables appear to provide such evidence. Specifically, the number of times the underlying accelerations cross the zero line within the movement, the number of 'significant deviations' within the acceleration trace, and the length of time for which the muscles are active (as measured by EMG) in relation to the duration of the movement. In the present experiment, then, these variables were measured in addition to the time required to prepare and initiate a movement performed under conditions conducive to either preprogramming or online preparation. Specifically, the movements were either completed as fast as possible, or at a considerably slower, more controlled speed. Each of the dependent variables displayed evidence of preprogramming in the movements completed at the fast velocity, and on-line preparation in the slower paced movements. Thus, in the slow condition, subjects appeared to rely more heavily on on-line prepared adjustments to produce an accurate outcome. The convergence attained between the various dependent measures lends power to the conclusions regarding hypothesized modes of control within the different speeds of movement.

Arm↗

PubMed1991

Preprogramming vs. on-line control in simple movement sequences.

In the present experiment the acceleration traces produced during a repetitive arm extension/flexion movement were measured in addition to the RT required to initiate such a movement. The speed at which this task was completed as well as the number of extension/flexion segments were varied to allow for either preprogramming or on-line control. Evidence from the acceleration traces and the RT data suggested that the movements completed as quickly as possible were preprogrammed; whereas, those completed more slowly were controlled on-line. Furthermore, the topologies of the power spectral density functions from the acceleration traces of each type of movement displayed characteristics typical of these forms of control.

Acceleration↗

PubMed1991

Learning the invariants of a perceptual motor skill.

The concept of invariant relative timing has typically been associated with the concept of a generalized motor programme. The present study approaches the phenomenon of invariant relative timing from the perspective of learning. The underlying question of concern for this study was, "What is learned." The specific question was whether relative timing is one of the essential properties of movement that is learned during skill acquisition. In the present experiment, subjects were given extensive practice in learning to track and reproduce a criterion waveform using a joystick control for their response. In order to test whether subjects learn the relative timing of a movement, they were transferred to tracking waveforms that were identical to the criterion in terms of relative timing, but different in terms of absolute timing. Measurements were taken on all waveforms in two conditions: (a) in a pursuit tracking condition where subjects were temporally constrained by the stimulus, and (b) in a reproduction condition where subjects' timing was not constrained. The outcome from both conditions gives support to the idea that humans learn invariant relative timing during the acquisition of a motor skill.

Adult↗

PubMed1991

Training coaches to observe and remember.

This study tested a video training method that was intended to improve the observational skills of soccer coaches. Three groups of soccer coaches were tested prior to and following a training period. The experimental group was exposed to a video training programme that was designed to highlight certain key elements of soccer team performance. Although both control groups were exposed to the same video excerpts as the experimental group, they were given different orienting activities. The subjects in control group 2 were asked to discuss these excerpts with a colleague and then write a report on what they had seen, while control group 1 members repeated prior test conditions that required them to remember certain events that preceded the scoring of goals. The results indicate that, although all coaches were incapable of remembering more than 40% of pertinent information, the subjects in the experimental group improved their ability to recall all events that surrounded the 'taking of shots'.

Adult↗

PubMed1991

Measuring the reliability of a computer-aided systematic observation instrument.

The inter- and intraobserver reliabilities of data collected by observers trained in the use of the coach analysis instrument (CAI) are reported. The CAI is part of the computerized coaching analysis system (CCAS). The CAI collects data related to the learning environment created by the coach in a team/sport practice situation. Both inter- and intraobserver reliabilities are reported for each of the instrument's seven dimensions as well as for the overall instrument. The reliability measures reported are total percent agreement (T) and Cohen's kappa (K). The results indicated that, although the overall coaching analysis instrument reached a T value of 90.8%, it failed to meet the 80% level for the K measure (K = 78.5%). A dimension by dimension examination of the data was undertaken to determine the reasons for these results and it was revealed that the problem was associated with three specific dimensions of the instrument.

Algorithms↗

PubMed1986

A systematic approach to analysing sports performance.

A systematic approach to the analysis of sporting events is discussed. The basic tenet is that objective quantification of critical events is required for a complete analysis. This approach encompasses diverse areas of methodology and research, such as quantification, biomechanics and physiology. The theoretical underpinning are behavioural, in so far as athletes produce observable behaviour that can be quantified and ultimately changed. Several areas of analysis are linked together in a general framework and each one of these areas is dealt with in detail.

Biomechanical Phenomena↗

PubMed1986

Physiological profiles of the Canadian Olympic Soccer Team.

Physiological profiles of elite athletes are becoming increasingly important both for the sport scientist and coach, primarily to effectively develop training programs and to use as a motivational tool in the pursuit of excellence. Descriptive profiles were developed on 16 aspirants of the Canadian Olympic Soccer team during their training program at U.B.C. Selected strength measures were obtained from a Cybex II isokinetic dynamometer at 30 degrees sec-1. Metabolic variables were derived utilizing a Beckman metabolic cart interfaced with a Hewlitt Packard 3052A data acquisition system. Protocols involved were the following: VO2max (initial velocity 8.05 km X h-1, greater than 0.805 km X min-1); Anaerobic speed test (AST) (20% grade, 12.8 km X h-1). the nonlinear increase in excess CO2 was utilized to determine the anaerobic threshold (AT). (Table: see text). Recommendations emphasized maintenance of low body fat, increasing maximal aerobic power by approximately 10% and creating a hams/quads ratio of 60%. Also, a nutritional survey and periodic evaluation of iron status is necessary for the athletes.

Adult↗

PubMed1986

The real time analysis of sport: an overview.

This paper describes a specific system analytic approach to the coaching and teaching of team sports. Computer technology is used to acquire the sequential history of critical events that occur during competition. A system is described that allows the analyst to enter data directly on a microcomputer and then compute relevant statistics for immediate use by the coach or teacher. The implications for the microcomputer system's use in high performance sports is also discussed.

Computers↗

PubMed1985

Does the complexity of S2 have any effect upon RT1? A controversy in the PRP literature.

The purpose of this experiment was to test several explanations that have been given to account for what has been termed the Psychological Refractory Period effect. Specifically the question addressed was what effect does varying the complexity and uncertainty of stimulus-response pairs have upon the subsequent reaction time. The experiment employed a within-subject Latin square design in which 12 undergraduates completed four test conditions on separate days. The task was to respond to a visual stimulus (maximum of 4 possible lights) by depressing a telegraph key with the index or middle fingers of either the right or left hands (maximum of 4 possible responses). It was possible to produce four conditions. Condition 1-1 (usual PRP paradigm), 1-2 (simple reaction time followed by a choice reaction time), 2-1 (choice RT followed by simple RT), and 2-2 (choice RT followed by choice RT). In addition, 36% of all trials were uninformed catch trials, i.e., either S1 and/or S2 did not occur when the subject was expecting it to occur. The subjects completed 50 single-choice control reaction-time trials before each condition. The interstimulus interval in all conditions for both experiments varied randomly among 100, 200, 300, and 400 msec. There was no statistical support for the claim that increasing the number of choices in S2-R2 will lengthen RT1. These results are discussed in terms of McLeod's (1977) parallel-processing model.

Adult↗