Previous research on contextual interference theory in controlled laboratory situations consistently illustrated that random practice was superior to blocked practice when learning motor skills. However, when considered in relation to physical education class settings the findings of the contextual interference experiments were not as uniform. Furthermore, the results of the contextual interference research were ambiguous when an open skill was used as the experimental task, with no definite trend evident. Random practice was found more effective for learning (del Rey, 1989) whereas French, Rink and Werner (1990) demonstrated blocked practice to be superior. In the present study, the influence of high and low contextual interference as practice schedules was investigated within an applied sports setting using an open sports skill as the experimental task. Two groups of boys and girls, 8-9 and 10-12 years of age, were taught a forehand tennis groundstroke using both their preferred and non-preferred hands over a ten week coaching and practice period. The findings showed that male subjects were significantly better at the experimental task than female subjects at the pre-test stage only. The result also demonstrated that the 10-12 year old subjects were significantly better than the 8-9 year olds at the task with the exception of the preferred hand at the post and retention test stage. The contextual interference effect was demonstrated in the retention phase on the preferred hand of the 10-12 year old subjects where the random practice group was significantly better than the blocked practice group in an applied sports setting. These findings were discussed in relation to the role of cognition in the learning of these motor skills and the influence of the subjects related background experiences.

Thesis (MScSportSc)--University of Stellenbosch, 2001. / ENGLISH ABSTRACT: The purpose of this study is to investigate the role of sport psychology injunior tennis and to determine: • whether coaches make use of psychological interventions, • whether coaches consider psychological interventions in junior tennis to be important, • what kind of psychological interventions coaches make use of, and • what kind of problems coaches encounter while teaching psychological interventions to junior tennis players. Questionnaires were mailed off to all professional tennis coaches who are registered with Tennis South Africa. The questionnaire which the coaches voluntarily answered, was an abbreviated, revised version of the questionnaire used by Gould et al. (1999a) for their study. \ The results of this study show that coaches: • regard the teaching of psychological interventions to junior tennis players as very important. • perceived the following as the most important psychological dimensions for junior tennis players: motivation, concentration, enjoyment, self-confidence and goal setting. • find the teaching process of psychological interventions to junior tennis players difficult. • encounter practical problems in the teaching of psychological interventions to junior tennis players. Lack of time is mentioned most often. Based on these outcomes, it is concluded that sport psychology has an important role to play in junior tennis. More research is needed to develop techniques and methods to effectively teach psychological interventions to junior tennis players. / AFRIKAANSE OPSOMMING: Die doel van die studie is om die rol van sportsielkunde in junior tennis te ondersoek deur die volgende te bepaal: • of afrigters van sielkundige intervensies gebruik maak, • of afrigters dink dat sielkundige intervensies belangrik is in junior tennis, • van watter sielkundige intervensies afrigters gebruik maak, en • watter probleme afrigters ondervind gedurende die onderrig van sielkundige intervensies aan junior tennisspelers. Vraelyste is gestuur aan aIle professionele tennisafrigters wat by Tennis Suid-Afrika geregistreer is. Die vraelys wat die afrigters vrywillig beantwoord het, was 'n verkorte, hersiene weergawe van die vraelys wat deur Gould et al. (1999a) in hulle studie gebruik is. Die resultate van die studie toon dat afrigters: • die onderrig van sielkundige intervensies aan junior tennisspelers as belangrik beskou. • die volgende sielkundige dimensies in junior tennis as die belangrikste beskou: motivering, konsentrasie, genot, selfvertroue en doelwitstelling. • die onderrigproses verbonde aan sielkundige intervensies moeilik vind. • praktiese probleme ondervind met die onderrig van sielkundige intervensies aan junior tennisspelers. 'n Gebrek aan tyd is uitgesonder as die probleem wat die meeste voorkom. Gebaseer op die resuitate, is daar tot die gevolgtrekking gekom dat sportsieikunde 'n belangrike rol te speel het in junior tennis. Verdere navorsing word benodig am tegnieke en metodes daar te stel om die sieikundige intervensies effektief aan junior tennisspelers te onderrig .

A Thesis Submitted to the Faculty of Education, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Master in Education / This study aimed to assess selected physiological, osmoregulatory and thermoregulatory responses to tennis play in children, Twenty-four young male tennis players (X age; 13.3+ 1.31 years) were stndied while playing for 90 min under warm environmental conditions (WBGT index= 13-19). Ad libitum consumption of pure water was permitted. Questionnaires were used in order to elicit information regarding the health status, degree of aeelimatizationnnd pre-match trait and state anxiety of the subjects. The physiological variables assessed. included pre- and post-match rectal temperature (T), heart rate (HR) and oxygen consumption (02) during the match. The biochemical observations included pre- and postmatch blood glucose, haematoerit (Ret), haemoglobin (lIb), plasma electrolyte (Na", Cl', K+, Mg++) and total plasma protein (TPP) concentrations. The findings )q~ed that the young tennis players investigated in this study experienced, ~de!'ate levels of pre-competitive trait and state amdety. The estimated nie.m exercise intensity of 50-55% of VOzmax for a duration of 90 min resulted. in a Tre increase of 0.73 •C. Mean percentage dehydration was 0.MO+O.25. Plasma volume (PV) changes were insignificant and were positively related to TPP changes. Mean plasma. Na" and CI- concentrations increased by 0.88 mmol.r" and 2.2 mmol.r:' respectively. The subjects' mean H... response (145 bpm) of a subset or the sample(n=13) and estimated VOz (21.38 ml.kg-l.min-~ represented a 55% of the age adjusted HRmax reserve and approximately a 50-55% of V02 max respectively. The time spent within the target heart rate range (60-85% HR. max reserve) comprised only 33% of the match duration. Mean energy expenditure was estimated to be 1772 KJ dUl'ing the 90 min period. Itwas calculated that in order to prevent harmful levels of dehydration under warm environmental conditions and at an exercise intensity of tennis play of approximately 55% of the age adjusted HR max reserve or 50-55% of V02 max, consumption of 4.44-6.81 mI.Kg-1.br-1 or 200-360 ml.hr" of water is recommended in young tennis players possessing a body mass of 45-53 Kg. The precise quantity was concluded to be a function of the mass and exercise intensity of the subjects and the environmental heat stress index during play. / Andrew Chakane 2018