Recently Hasegawa et al (2007) investigated the foot strike patterns and ground contact times during a half marathon. They found that foot strike patterns were related to running speed with forefoot and midfoot strikers exhibiting shorter ground contact times and faster running speeds. The purpose of this study was to conduct a similar analysis in male 800m runners. Ten seeded sub-elite races were filmed on one evening at a British Milers Club meeting. Seventy one runners were filmed by a 100-Hz video camera at a height of 15 cm placed 15 m from the start / finish line. All runners completed their race and were captured on both laps of the race. Average race time showed a range of 14.46 s from 107.53 to 121.99 s with a mean 115.21 +/- 3.41s and coefficient of variation of 3.0%. The mean contact time for lap 1 was 156 +/- 12 ms and for lap 2 it was 168 +/- 16 ms. On lap 1 35%, 48% and 17% of runners made initial ground contact with the forefoot, midfoot and heel respectively. For lap 2 these values were 34%, 51% and 15%. Two way ANOVA s comparing ground contact time across the different races for lap 1 and lap 2 revealed significant main effects for both lap (F1,61 = 46.315; P < 0.000) and race (F9,61 = 2.766; P = 0.009). Those runners who displayed the same foot strike pattern on both laps (N = 48) were entered in to a 2x3 ANOVA comparing ground contact times by lap and foot strike position. This showed significant main effects for both lap (F1,45 = 32.600; P < 0.000) and foot strike position (F2,45 = 12.779; P < 0.000). Post-hoc analysis revealed significant differences between the heel and both other contact points. The shortest ground contact times were for the forefoot (156 ms) followed by midfoot (161 ms) and heel (177 ms). For each contact point there was a significant increase (forefoot - t15 = 2.782, P = 0.014; midfoot - t24 = 3.501, P = 0.002; heel - t8 = 5.292, P = 0.001) in ground contact time between lap 1 and lap 2. Linear regression revealed a significant relationship between average running speed and ground contact time for both lap 1 and lap 2, however only a small portion of average running speed was accounted for (10.3% lap 1 and 11.9% lap 2). This study found that foot strike patterns were related to running speed. The relationship between ground contact time and running speed supports the notion of a spring-mass model of locomotion. Over the course of an 800m race ground contact time increased irrespective of foot strike position. This implies an element of fatigue, with runners presumably requiring longer to generate the same impulse. Alternatively, this may have been a reflection of the pacing strategy during the races, with all races adopting a first lap that was quicker than average race speed.
© 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.