Effect of sand versus grass training surfaces during an 8-week pre-season conditioning programme in team sport athletes

Abstract

This study compared the use of sand and grass training surfaces throughout an 8-week conditioning programme in well-trained female team sport athletes (n = 24). Performance testing was conducted pre- and post-training and included measures of leg strength and balance, vertical jump, agility, 20 m speed, repeat speed (8 × 20 m every 20 s), as well as running economy and maximal oxygen consumption (VO_2max). Heart rate (HR), training load (rating of perceived exertion (RPE) × duration), movement patterns and perceptual measures were monitored throughout each training session. Participants completed 2 × 1 h conditioning sessions per week on sand (SAND) or grass (GRASS) surfaces, incorporating interval training, sprint and agility drills, and small-sided games. Results showed a significantly higher (P < 0.05) HR and training load in the SAND versus GRASS group throughout each week of training, plus some moderate effect sizes to suggest lower perceptual ratings of soreness and fatigue on SAND. Significantly greater (P < 0.05) improvements in VO_2max were measured for SAND compared to GRASS. These results suggest that substituting sand for grass training surfaces throughout an 8-week conditioning programme can significantly increase the relative exercise intensity and training load, subsequently leading to superior improvements in aerobic fitness.     

The effect of alterations in foot centre of pressure on lower body kinematics during the five-iron golf swing

ABSTRACT

The research aimed to evaluate the effects of an intervention aimed at altering pressure towards the medial aspect of the foot relating to stability mechanisms associated with the golf swing. We hypothesised that by altering the position of the foot pressure, the lower body stabilisation would improve which in turn would enhance weight distribution and underpinning lower body joint kinematics. Eight professional golf association (PGA) golf coaches performed five golf swings, recorded using a nine-camera motion analysis system synchronised with two force platforms. Following verbal intervention, they performed further five swings. One participant returned following a one-year intervention programme and performed five additional golf swings to provide a longitudinal case study analysis. Golf performance was unchanged evidenced by the velocity and angle of the club at ball impact (BI), although the one-year intervention significantly changed the percentage of weight experienced at each foot in the final 9% of downswing, which provided an even weight distribution at BI. This is a highly relevant finding as it indicates that the foot centre of pressure was central to the base of support and in-line with the centre of mass (CoM), indicating significantly increased stability when the CoM is near maximal acceleration.     

Stimulus Velocity,Duration and Uncertainty as Determiners of Response Structure and Timing Accuracy

Abstract

The present experiments examined the effects of stimulus velocity, stimulus duration, and stimulus uncertainty on the spatial-temporal structure and timing accuracy of coincident timing responses. The results of Experiment 1 indicated that the response structure for aimed movements differed from that of ballistic movements but response accuracy was comparable for both movement conditions. However, when information concerning the stimulus velocity was provided, the responses to the faster stimuli (i.e., stimuli of shorter duration) appeared to be “speeded up” copies of those to slower stimuli and response accuracy increased as the stimulus velocity increased (i.e., stimulus duration decreased). When the stimulus velocity was not known, subjects initiated a common response for approximately 260 msec and response accuracy appeared to decrease as the stimulus velocity increased (i.e., stimulus duration decreased). Experiment 2 indicated that the stimulus duration rather than the stimulus velocity was the major determiner of both the spatial-temporal structure and timing accuracy and that a very fast and a very slow stimulus will be responded to similarly when the stimulus duration remains constant.     

Competition and Instructional Set Effects On the Speed and Accuracy of a Throwing Task

Abstract

Two experiments were conducted to investigate the effects of competition and instructional sets on the speed and accuracy of a dart-throwing task. In both experiments individuals competed against another subject on one day, and performed under noncompetitive conditions on a second day. The five distinct instructional sets varied from extreme emphasis on speed to extreme emphasis on accuracy. Multivariate analyses of variance revealed main effects for instructional sets on speed and accuracy in both experiments. Strong tradeoffs occurred with speed slowing and accuracy improving as the instructional emphasis changed from speed to accuracy. A competition by instructional sets interaction in Experiment 2 indicated that competition facilitated speed when speed was important, but when instructions emphasized accuracy, speed was slower in competition than in noncompetition. Accuracy was not affected by competition.     

Different types of compression clothing do not increase sub-maximal and maximal endurance performance in well-trained athletes

Abstract

Three textiles with increasing compressive surface were compared with non-compressive conventional clothing on physiological and perceptual variables during sub-maximal and maximal running. Fifteen well-trained endurance athletes (mean ± s: age 27.1 ± 4.8 years, [Vdot]O_2max 63.7 ± 4.9 ml · min^?1 · kg^?1) performed four sub-maximal (～70%[Vdot]O_2max) and maximal tests with and without different compression stockings, tights, and whole-body compression suits. Arterial lactate concentration, oxygen saturation and partial pressure, pH, oxygen uptake, and ratings of muscle soreness were recorded before, during, and after all tests. In addition, we assessed time to exhaustion. Sub-maximal (P = 0.22) and maximal oxygen uptake (P = 0.26), arterial lactate concentration (P = 0.16; 0.20), pH (P = 0.23; 0.46), oxygen saturation (P = 0.13; 0.26), and oxygen partial pressure (P = 0.09; 0.20) did not differ between the types of clothing (effect sizes = 0.00–0.45). Ratings of perceived exertion (P = 0.10; 0.15), muscle soreness (P = 0.09; 0.10) and time to exhaustion (P = 0.16) were also unaffected by the different clothing (effect sizes = 0.28–0.85). This was the first study to evaluate the effect on endurance performance of different types of compression clothing with increasing amounts of compressive surface. Overall, there were no performance benefits when using the compression garments.     

A physiological and biomechanical comparison of over-ground,treadmill and ergometer wheelchair propulsion

Abstract

The purpose of the study was to determine which laboratory-based modality provides the most valid physiological and biomechanical representation of over-ground sports wheelchair propulsion. Fifteen able-bodied participants with previous experience of wheelchair propulsion performed a 3-minute exercise trial at three speeds (4, 6 and 8 km ? h^–1) in three testing modalities over separate sessions: (i) over-ground propulsion on a wooden sprung surface; (ii) wheelchair ergometer propulsion; (iii) treadmill propulsion at four different gradients (0%, 0.7%, 1.0% and 1,3%). A 0.7% treadmill gradient was shown to best reflect the oxygen uptake (7.3 to 9.1% coefficient of variation (CV)) and heart rate responses (4.9 to 6.4% CV) of over-ground propulsion at 4 and 6 km ? h^–1. A 1.0% treadmill gradient provided a more valid representation of oxygen uptake during over-ground propulsion at 8 km ? h^–1 (8.6% CV). Physiological demand was significantly underestimated in the 0% gradient and overestimated in the 1.3% gradient and wheelchair ergometer trials compared to over-ground trials (P<0.05). No laboratory-based modality provided a valid representation of the forces applied during OG (≥ 18.4% CV). To conclude, a 0.7% treadmill gradient is recommended to replicate over-ground wheelchair propulsion at lower speeds (4 and 6 km ? h^–1) whereas a 1.0% gradient may be more suitable at 8 km ? h^–1.     

“Three Specially Selected Athletes” and a Recapitulation of the Pennsylvania Walking Purchase of 1737

Abstract

The generality of the variability in practice prediction, arising from Schmidt's schema theory (1975) of motor learning was tested on young children. More specifically, the structure of the variability session and its subsequent influence on transfer performance to a novel variation of the task was examined. Children tossed a weighted bean bag to a fixed target location. Three groups experienced variability in practice with four bean bags of varying weights (3, 4, 5, and 6 oz.); however, the trial-by-trial presentation of each weight was different for each group. One group received a random presentation of each weight from trial to trial while another experienced random presentations of a weight for blocks of three trials. The third variability group received blocked practice with six trials per block for each weight. All variability groups experienced the same amount of practice at each weight. A constant practice group experienced only a single weight. Following 24 practice trials, all subjects transferred outside the range of previous experience, receiving three trials with one of two possible test weights (2 oz. or 7 oz.). The results indicated that the variability group practicing with blocks of three trials at each variation led to superior performance at transfer to novel variations of the task. Overall, the experiment suggested that transfer performance for children is affected by the appropriate structure of variable practice which formulates the schemata for movement production.     

Influence of Decision-Making on Attitudes,Creativity, Motor Skills and Self-Concept in Elementary Children

Abstract

Attitudes, creativity, self-concept and motor skills were measured to determine the influence of decision-making on elementary children. Three groups of children (N = 208) were tested, one group was taught with the teacher dominating all classroom decisions, another group was encouraged to share in the decision-making, and a third group served as a control. Data were collected immediately before and after an eight-week instructional period. MANCOVA indicated that the two treatment groups had significantly higher scores than did the control group, and the shared decision-making group scored significantly higher than the teacher dominated group on measures of creativity, motor skills and self-concept. A 2 (treatment) × 2 (sex) × 5 (grade) ANOVA revealed significantly more positive attitude scores for children allowed to make decisions regarding their learning. Further, Pearson product-moment correlation showed the tested variables to be independent measures of a child's development.     

The Application of a Multiple Measurement Approach to Investigate the Effects of a Dance Program on Educable Mentally Retarded Adolescents

Abstract

Little evidence exists to assess the effects of dance training on special populations. Research in this field has relied on pretest-posttest methods for gathering data. While such data gathering methods may be appropriate for particular research problems, alone they may be inadequate for broad-based, exploratory investigations of programs and effects. The present study is an example of a multiple measurement approach that uses eight measurements, in combination, to answer four research questions regarding the physical and social effects that occur when a group of educable mentally retarded adolescents is exposed to a 10-week dance program. The findings revealed that four students showed improvement in both social and physical behaviors, seven students showed improvement in either social or physical behaviors, and two students showed no improvement. There was no evidence of a “transfer effect” due to participation in the program, and some students' behaviors were affected by external factors. The authors found the approach useful for identifying multiple effects and generating hypotheses for further study.