TEMPORAL ANALYSIS OF THE JAVELIN THROW
AbstractMETHODS This study divided the javelin throw into five time segments, based on six landmark events, including foot touchdowns and javelin release. The first time segment, the approach time segment (APP), is the time from the start of the approach (first forward motion) to the first throwing foot touchdown after withdrawal begins. The second time segment is the withdrawal time segment (WDL), which is the time from the throwing foot touchdown at beginning of withdrawal to the first opposite foot touchdown after withdrawal completed. The next time segment, the penultimate step time segment (PNU), is the time from opposite foot touchdown at completion of withdrawal to next touchdown of throwing side foot. The preparatory step time segment (PRP) is the time from touchdown of throwing side foot to touchdown of brace (opposite) foot. The final time segment is the release time segment (REL), or the time from touchdown of brace foot to javelin release. Eleven elite male throwers were analyzed as a group. Videographic records of elite male throwers at various international events over the 1992-1993 seasons, as well as the 1992 Olympics and 1993 and 1995 World Championships, were examined. In addition, performances of top U.S. male throwers from the 1988 and 1992 U.S. Olympic Trials, and the 1993 and 1994 Olympic Festivals, were analyzed. The analysis consisted of digitizing the raw videographic records using frame advance. The five throwers with more than ten analyzed throws were also analyzed individually and with each other (major group). The average segment durations for each thrower were calculated and grouped together. The averages for the major throwers were also grouped together. A total of ninety-five throws were analyzed, with seventy-three of those coming from the five major throwers. Correlation analysis was performed on all five major throwers and the four groups to determine relationships between the distance thrown and time segment duration, as well as between time segments. Regression analysis was also performed on the individual and the group data to determine a predictive equation for distance thrown. RESULTS Several significant relationships (p < 0.05) were found. In general, a shorter release time segment was correlated with a greater distance thrown. This suggested that speed generated early in the running phase may be carried over or maintained in later segments, aiding in the generation of release velocity. Thus a major suggestion for improving performance would be to try to increase the running speed and the extent to which this speed is carried over into the throw. Different individual styles also appeared to be present, suggested by the different results for the individual throwers. The styles could not be sorted into common classifications A predictive equation for distance thrown for the group was determined to be: DIST = 105.757 - 241.865 (REL) + 1.349 (APP) - 4.129 (WDL), where DIST is the distance thrown.
Coaching and Sports Activities
Authors can retain copyright, while granting the International Society of Biomechanics in Sports (ISBS) the right of first publication.