An Analysis of World Weightlifting Records

Abstract

Summary knowledge of results (KR) involves delaying the presentation of KR until a predetermined number of trials has been completed. Schmidt, Young, Swinnen, and Shapiro (1989) found an optimal summary length of 15 trials (compared to 1, 5, and 10) and Schmidt, Lange, and Young (1990) found an optimum length of 5 trials (compared to 1, 10, and 15) for 1 and 2 kinematic degree of freedom timing tasks, respectively. Experiment 1 was designed to determine the optimal summary length for learning a simple isometric force production task. The results indicated better retention for the 16-trial summary than for 8- or 1-trial summaries. Experiment 2 was an initial attempt to determine the locus of the 16-trial summary effect. Specifically, Experiment 2 focused on the role played by both the information provided in the summary presentations and the practice per se of the first 14 trials in the 16-trial block. The results suggest KR is important to ensure response stability. However, it also appears important to restrict the subject's immediate utilization of KR. This latter requirement may potentially aid the parameterization process, resulting in a reduction in response bias.     

An Analysis of the Validity of the Three-Mile Run as a Field Test of Aerobic Capacity in College Males

Abstract

The purpose of the present investigation was to examine the concurrent and construct validity of the three-mile (4.83 km) run as afield test of aerobic capacity. Subjects included 109 college-aged males whose three-mile run time (M = 1310.31 ± 184.48 s) was measured. Fifty of the subjects were given a maximal treadmill stress test, and their peak oxygen consumption (VO₂peak) (M = 54.23 ± 7.08 ml.kg^?1.min^?1) was measured. The three-mile run was conducted on an outdoor 0.25 mile (0.425 km) track, and split tunes were recorded each 110 yds (100.32 m) for the first and last laps and total time was recorded for laps 2 through 11. The correlation coefficient between the run time and VO₂peak was -.58, indicating only moderate concurrent validity for the run as afield test for aerobic capacity. A factor analysis conducted on the split time data revealed a three-factor structure of a stable pace phase, an initial sprint, and a final sprint with the stable pace factor accounting for most of the common factor variance (69%). The three-mile run time was used to discriminate successfully between two known groups of subjects in aerobic capacity. These data provide a degree of support for the construct validity of the three-mile run as afield test of aerobic capacity.     

The Metabolic Cost of Two Ranges of Arm Position Height with and without Hand Weights during Low Impact Aerobic Dance

Abstract

To determine the energy cost of low impact aerobic dance while varying arm movement height and the use of hand weights, 10 adults volunteered to participate in four choreographed trials. All trials consisted of identical leg movements. Arm movements, however, were performed above shoulder level both with and without 0.9-kg hand weights and below shoulder level both with and without 0.9-kg hand weights. Open circuit spirometry was employed throughout the 10-min videotape guided trials, and heart rate was measured by telemetry. Neither the use of hand weights nor the change in arm position height significantly altered the energy cost of low impact aerobic dance. However, heart rate responses were significantly different. Caution should be observed by aerobics instructors and participants as to the use of heart rate as an indicator of intensity for low impact aerobic dance.     

Active Transportation to School

Abstract

Cinematographical analysis was used to compare spatial and temporal relationships of ten skilled and ten non-skilled performances of the standing broad jump. Means of the extent and duration of major joint action for the two levels of skill were represented graphically. Characteristic likenesses appeared in the general patterns of movement of limbs and in proportion of time consumed by the phases of the movement. Characteristic differences were found in angles of take-off and of landing and in extent and duration of specific joint actions. Greater extent of movement occurred in the skilled performances. The latter characteristically used more time in hip flexion and less time in knee extension.     

Visual search,anticipation and expertise in soccer goalkeepers

We used a novel methodological approach to examine skill-based differences in anticipation and visual search behaviour during the penalty kick in soccer. Expert and novice goalkeepers were required to move a joystick in response to penalty kicks presented on film. The proportion of penalties saved was assessed, as well as the frequency and time of initiation of joystick corrections. Visual search behaviour was examined using an eye movement registration system. Expert goalkeepers were generally more accurate in predicting the direction of the penalty kick, waited longer before initiating a response and made fewer corrective movements with the joystick. The expert goalkeepers used a more efficient search strategy involving fewer fixations of longer duration to less disparate areas of the display. The novices spent longer fixating on the trunk, arms and hips, whereas the experts found the kicking leg, non-kicking leg and ball areas to be more informative, particularly as the moment of foot-ball contact approached. No differences in visual search behaviour were observed between successful and unsuccessful penalties. The results have implications for improving anticipation skill at penalty kicks.     

The vibrational mode structure of a golf ball

In this paper, we report the discrete frequencies at which golf balls can vibrate, the mode patterns of these vibrations and how these modes can be excited. There are two broad classes of modes: those that radiate sound waves and those that do not. Both silent and acoustic modes are excited by tangential (i.e. spin-producing) impact forces; only acoustic modes are excited by radial impact forces. Exact analytical results for a homogeneous ball core are compared with finite element numerical results for both a core and a model two-piece ball. Correspondences are readily established for the important low-frequency modes, and the good agreement suggests the validity of these results for real golf balls. The results potentially provide the basis for a rapid, simple and non-destructive method of measuring the effective high-frequency elastic shear modulae of balls (and ball cores) as well as a method for 'tuning' the performance of balls for specific clubs. Some of these aspects are explored further in our companion paper in this issue.     

Motivation for physical activity in young people: entity and incremental beliefs about athletic ability

Three studies are reported of children and youth aged 11–19 years (n?=?3478) examining the nature of beliefs about athletic ability. Drawing on related research in academic, moral and stereotyping domains, development of a psychometric instrument assessing athletic ability beliefs is detailed. Support was found for a multidimensional hierarchical structure that is invariant across age and gender. Confirmatory factor analysis revealed a structure comprising two higher-order factors of entity and incremental beliefs underpinned by beliefs that athletic ability is stable and a gift (entity), and is open to improvement and can be developed through learning (incremental). Incremental beliefs, indirectly through a task goal orientation, and entity beliefs directly, predicted self-reported amotivation towards physical education and sport. On the other hand, enjoyment of physical activity in youth was predicted directly by task orientation and incremental beliefs. Predictions concerning the moderating role of perceived competence were not supported. Our findings highlight the importance of ability beliefs and goals in understanding the determinants of physical activity in children and youth.     

Why do high jumpers use a curved approach?

Currently, all elite high jumpers use the Fosbury Flop technique with a curved approach. This suggests that the curved approach presents some clear advantage, although there is no general agreement upon the mechanism or the mechanics. This study aimed to determine the characteristics of the approach curve and to investigate how it contributes to the generation of somersault rotation. A simple theoretical model was used to demonstrate that a tightening approach curve would change the inward lean towards the centre of the curve into outwards lean. Three-dimensional video analysis was used to record the performances of two elite male high jumpers in competition. It was found that in each case the radius of the approach curve and the inward lean angle both decreased towards the end of the approach. The amount of outward lean angular velocity generated was shown to be a major proportion of the required somersault angular velocity for a jump. It was concluded that the main advantage of a curved approach was that it resulted in the generation of somersault velocity providing the curve tightened towards the end of the approach.     

Contraction force specificity and its relationship to functional performance

Abstract

Best practice for improving strength and power through resistance strength training has been the subject of much research and subsequent conjecture. Much of the conjecture can be attributed to methodological discrepancies. The type of dynamometry used in testing, the training experience of research participants, the specific technique employed in a lift, and the methods of collection and calculation all impact on the final variables of interest. This review examines contraction force specificity by first addressing the methodological issues surrounding our interpretation of the results. Then we address the kinematics and kinetics associated with single and multiple repetitions in relation to the development of strength, power, and functional performance. This discussion provides the delimitations for analysis of subsequent training studies. Finally, recommendations are formulated with the aim of assisting assessment and training practice as well as providing directions for future research. The results of this review suggest that the enhancements in performance resulting from resistance training are context specific in experienced resistance-trained participants. Thus, specific conditioning could be required to achieve improvements in functional performance in this group.