A comparison of the reverse and power punches in oriental martial arts

Abstract

In this study, we compared mechanical factors in the reverse and three-inch power punches. Twelve expert male martial artists stood on a force plate, and executed reverse and power punches against a padded target fixed to a wall-mounted force plate. The force plates measured horizontal forces, and subsequently impulses and body centre of mass velocity changes. The motions of four markers attached to the arm were also collected, and were used to compute the horizontal velocities of the knuckle and of the arm centre of mass. The power punch produced smaller velocities immediately before impact than the reverse punch for the whole-body centre of mass (0.14 vs. 0.31 m · s^?1), for the arm centre of mass (2.86 vs. 4.68 m · s^?1), and for the knuckle (4.09 vs. 6.43 m · s^?1). The peak force exerted by the fist was much smaller in the power punch than in the reverse punch (790 vs. 1450 N). However, the linear impulse exerted by the fist during the first 0.20 s of contact was slightly larger in the power punch than in the reverse punch (43.2 vs. 37.7 N · s). The results indicate that the power punch is less potent than the reverse punch, but slightly more effective for throwing the opponent off balance.     

Object Rotation Effects on the Timing of a Hitting Action

Abstract

We investigated how perturbing optical information affects the guidance of an unfolding hitting action. Using monocular and binocular vision, six participants were required to hit a rectangular foam object, released from two different heights, under four different approach conditions, two with object rotation (to perturb the viewed surface area) and two without. Participants made more misses under monocular conditions, and the presence of rotation had a significant effect on the duration between the arm's peak velocity and its contact with the object. We conclude that binocular information contributes to the timing of interceptive tasks. In addition, the guidance of interceptive actions does not appear to be based solely on object expansion information picked up from the viewed surface area.     

Relations between teachers’ emotions in teaching and their approaches to teaching in higher education

This study investigated the relations between teachers’ emotions in teaching and their approaches to teaching in individual courses. It is derived from two fields of study that have hitherto been largely unconnected in higher education. While the research literature shows (a) a range of variables are related to the teaching approaches that teachers adopt and that these approaches are related to the quality of their students’ learning, and (b) that the emotional experience of teachers is an important factor in teaching, no studies have been reported on the connections between emotions and approaches in teaching in higher education. Two self-report questionnaires: the Approach to Teaching Inventory-Revised and the Emotions in Teaching Inventory, were completed by a sample of 175 Australian higher education teachers. The results suggest that there are significant relations between the ways teachers emotionally experience the context of teaching and the ways they approach their teaching, with positive emotions being associated with student-focused teaching approaches and negative emotions with transmission approaches. The relations help explain why new teaching strategies may not be successful or not even adopted.     

Initial hydration status, fluid balance, and psychological affect during recreational exercise in adults

There is little information on the impact of hydration status on the psychological response to exercise despite potential implications for adherence to an exercise programme and for overall health and fitness. We investigated initial hydration status, fluid balance, and psychological responses associated with a typical recreational exercise session in healthy adults. Fifty-two participants performed a freely chosen gymnasium-based exercise session at a fitness centre, with ad libitum access to fluids. Urine samples were collected on arrival for analysis of osmolality. Sweat loss was estimated from the change in body mass after correction for fluid intake and urinary losses. Subjective psychological ratings were recorded before and after exercise. Pre-exercise urine osmolality was above 900 mOsmol · kg(-1) (used as a threshold for hypohydration) in 37% of participants. Fluid intake during exercise was 390 ± 298 mL, while estimated sweat loss was 794 ± 391 mL. The percentage change from pre-exercise body mass was -0.62 ± 0.20%. Physically active adults who arrived to take part in exercise hypohydrated reported more negative changes in psychological affect in response to their subsequent freely chosen recreational exercise session than those classified as euhydrated prior to exercise (-0.2 ± 0.7 vs. 0.8 ± 0.7; P < 0.005).     

Development of expertise in elite and sub-elite British rugby league players: A comparison of practice experiences

Previous studies have investigated how individuals reach an expert level by counting the number of hours engaged in specific practice types. Here we sought to understand and compare the microstructure (e.g. practice tasks undertaken) of these practice hours experienced by elite and sub-elite British rugby league players. Semi-structured interviews explored the practice experiences of eight international and eight domestic level players. A two-staged thematic analysis was used to interpret the data. The analysis revealed that both player groups experienced a rich and narrow landscape of affordances and were exposed to early diversification of sports experiences during childhood. Differences were identified in domestic level players’ experiences of amateur and professional sports, where episodes of negative developmental environments were reported. International players’ practice experiences revealed differences in their professional careers, where exposure to scenario-based practice and dynamic learning environments were reported. The findings suggest that insights from ecological dynamics provide a suitable theoretical framework to guide coaches in the design of practice environments that should consider the physical, psychological, emotional and social dimensions of expertise acquisition.