Laterality, the dominance of one hemisphere, and the effect of these two phenomena on sports performance capacity have yet to be described in detail. Methods 275 kayakers and canoeists were examined twice annually using extensive kinetic and biomechanical equipment. The athletes were members of a state-wide canoeing club (national junior elite athletes). The main focus of the study was the correlation between (a) force differences arising between the left and right upper extremity and (b) athletic performance under laboratory conditions and field conditions (flat water). The following data was gathered: selected strength capacities (maximum force [FMax]) of the upper arm flexor at a static strength measurement system, force curves at the measuring paddle during exercise tests using the canoe counter current system and canoeing times in flat water over 250 m and 2,000 m during the course of the year. Results The results of the static maximum force test showed that the difference in maximum force between the left and right arm increases with age. As maximum force increases, the difference in the mean value of maximum force seems to increase as well. The longitudinal study included only right-handed athletes. In the longitudinal group the assumption seems to be confirmed that right-handers also have greater force in their preferred extremity. Further longitudinal analyses showed that the higher maximum force achievement changes from the right into the left arm with some test subjects. Discussion These results show that it is not always possible to determine which side has greater maximum force solely on the basis of handedness. According to Vagenas & Hoshizaki (1988) bilateral differences, which are frequently observed during symmetrical physical activities, may be attributable to the systematic combination of structural and neuromuscular factors. However, there is ongoing controversy about the relationship between preferred extremity (preference dominance) and the extent of force development (achievement dominance). The preferred extremity is commonly believed to possess the higher maximum force level. Therefore it could be concluded that the morphological organization of the human locomotor system forms the very basis for locomotor movement symmetries. However, due to diverse factors such as differences in extremity lengths and the attendant force levels, movement asymmetries may arise during cyclic movements such as walking and running. This observation is consistent with Starosta`s (2002) theory, which holds that ontogenetically induced upper extremity growth differences lead to different leverage lengths and attendant levels of force. Apart from that, the dominant extremity might be used instinctively for movement guidance e.g. during strength training. References Starosta W: Die Symmetrie und Asymmetrie der Bewegung gemäß der Bernstein-Theorie. Leistungssport 2002; (32), 1: 59-62. Vagenas G, Hoshizaki B: Evaluation of rear foot asymmetries in running with worn and new running shoes. Int J Sport Biomech 1988, 4: 220-230.
© Copyright 2009 14th annual Congress of the European College of Sport Science, Oslo/Norway, June 24-27, 2009, Book of Abstracts. Veröffentlicht von The Norwegian School of Sport Sciences. Alle Rechte vorbehalten.