The aim of this study was to provide a comprehensive analysis of key biomechanical variables in race walking through the analysis of elite athletes in both competitive and laboratory settings. Video data from two 3CCD camcorders of athletes competing over 10 km (juniors only), 20 km, and 50 km were collected at three international competitions. For the 20 km and 50 km events, multiple recordings were made to identify if kinematic changes occurred. In addition, synchronised high-speed video, electromyography and ground reaction force data were collected of 20 elite race walkers in a laboratory setting and combined to calculate joint moments, power and work. The key discriminants with regard to better performances were long step lengths and high cadences, and the contribution made by flight distance to step length (approximately 13%) was particularly important, regardless of race distance or age category. Step length ratio was a better predictor of optimum step length than absolute values and a ratio of about 70% was found in the fastest athletes. Although reductions in step length and flight distance were a major cause of decreased speed over both 20 km and 50 km, many gait variables did not alter greatly, showing that these elite athletes were able to maintain their techniques despite fatigue. The foot position ahead of the body at initial contact (approximately 20% of stature) need not be detrimental to fast walking if the athlete has the strength to overcome the potentially negative effects; instead, it can be beneficial to increase this distance in achieving a greater step length and could be a key area for women in particular to develop. The hip muscles were the main source of energy generation, with both flexors and extensors doing more positive work than any other muscle group (22.4 ± 7.1 J and 42.3 ± 10.1 J respectively), although the ankle plantarflexors also generated considerable energy before toe-off (16.4 ± 3.8 J). A hip extensor moment that occurred during late swing and early stance helped maintain forward momentum as it reduced the braking peak force and duration of the negative anteroposterior force. The knee had little involvement in energy generation because of its predominant role as a rigid lever during stance, and absorbed considerable energy during swing (–46.4 ± 9.5 J). However, its abnormal movement that was dictated by the race walking rule also had an important role in maintaining contact with the ground and reducing vertical forces so that visible loss of contact was avoided. The study was the first to analyse in such depth the biomechanics of elite male and female race walkers across all competitive distances and its results could be used to develop a technical manual for this Olympic event and greatly impact on coaching practice.
|Divisions:||Carnegie > Sport|
|Date Deposited:||22 Dec 2014 11:43|
|Last Modified:||28 May 2016 04:28|
|Item Type:||Thesis (Doctoral)|