Author(s): KADONO, H., Institution: SENDAI UNIVERSITY, Country: JAPAN, Abstract-ID: 1698

INTRODUCTION:
In 800m running event, it is reported that the pacing strategy of world record was positive pacing [1], on the other hand there were various pacing strategies in Olympic games [2] and World Championships [3]. Tactical preparations that improve ability to change running speed and respond dynamically changes in speed are required for runners and coaches when they prepare for championship races. In running biomechanics, running speed, step frequency and step length are basic parameters which represent running technique. Previous studies focused on only paces (time or speed), but in this study focused on not only speed but also step frequency and time and aimed to investigate technical characteristics during men’s 800m races in World Athletics Championships.
METHODS:
This study used a digital video camera (Panasonic, HC-VX992, 60Hz) to videotape all heats of men’s 800m (6 heats for 1st round, 3 heats for semi-final and a final) in the World Athletics Championships, Oregon 2022 (WC22). This study used official race analysis on the WC22 web site to classify all heats into positive pacing races (POS) and negative pacing races (NEG). POS was the heat that faster 1st lap, NEG was the heat that faster 2nd lap. First 2 finishers of each heat were picked out and they were classified into POS and NEG. Every 100m split times on the WC22 website were used to calculate average running speed of each 100m for 8 all sections. The video camera movies were used to measure the time which runner took 10 steps with their natural running form in each 100m section, followed by calculating average time which runner take a step. Step frequency (SL) in each 100m section was calculated by inverse step time, and step length (SL) was calculated by running speed divided by SF.
RESULTS:
6 of 10 heats were POS (n=12) and 4 of 10 heats were NEG (n=8). There was no significant difference in goal time between POS (1:45.32±00.56) and NEG (1:46.25±02.05). POS was significantly faster in 1st lap time than NEG (p<0.05, d=1.248), especially running speed was significantly faster (200-300m: p<0.001, d=0.214; 300-400m: p<0.01, d=0.286) and SF was higher (n.s.) in 200-400m. And SL was larger in 100-400m (n.s.). On the other hand, NEG was significantly faster in 2nd lap time than POS (p<0.001, d=0.433), especially running speed was faster (500-600m: p<0.01, d=0.171; 600-700m: p<0.01, d=0.137) and SF was higher (n.s.) in 500-700m. And SL was almost the same as POS in 400-800m.
CONCLUSION:
There were both POS and NEG in WC22, and running speed, SF and SL were different between 2 types of pacing. In POS, it was faster in 200-400m with high SF and large SL. In NEG, it was faster in 500-700m with not large SL but high SF. This study suggests that when runners and coaches do tactical preparation for championship races, they should take into account not only pace or speed but also techniques (changing SF and SL).
REFERENCES
1. Tucker et al., IJSPP, 2006　2. Thiel et al., JSS, 2012　3. Sandford et al., IJSPP, 2018