engleski

Differences between 100 m, 400 m and middle distance runners in explosive leg strength and leg stiffness tests

Introduction The performance in running events is determined by several neuromuscular factors, but the optimal level of muscle power, strength and stiffness for specific running events is not fully elucidated. The purpose of this study is to investigate the difference in those parameters among athletes who compete in different running events. Methods Thirty-one regional to national level male athletes: ten 100m (S) (182.6± ; 5.7 cm, 75.7± ; 4.2 kg), personal best (PB) on 100m sprint = 10.87± ; 0.41s, eleven 400m (S4)(181.9± ; 4.7 cm, 74.0± ; 5.0 kg), PB on 400m 49.5± ; 1.9s, and ten middle distance runners (MD) (180.1± ; 5.4 cm, 68.7± ; 6.3 kg) participated in this study. Several biomechanical variables were measured on a force plate (QuadroJump, Kistler) for evaluation of explosive leg strength: the squat jump (SJ), counter movement jump performed with both legs without hands (CMJ) and with hands (CMJH), as well as CMJ performed on each leg separately (CMJL and CMJR). Leg stiffness was evaluated by performing ten successive maximal hops (HOP) on the same force plate. Standing long jump (SLJ), as a commonly used field test, was also measured. Analysis of variance (with Scheffe’ s post hoc test) was used to determine significant differences between groups of runners. Results The 100m sprinters achieved the highest values while the middle distance runners achieved the lowest values in all measured parameters (SJ: 56.4± ; 6.0 cm, 46.3± ; 3.6 cm, 42.0± ; 3.4 cm ; CMJ: 62.3± ; 4.8 cm, 52.9± ; 3.5 cm, 45.4± ; 4.1 cm ; CMJH: 68.8± ; 6.1 cm, 61.8± ; 3.5 cm, 51.8± ; 4.1 cm ; CMJL: 42.5± ; 8.4 cm, 34.1± ; 1.7 cm, 30.4± ; 4.6 cm ; CMJD: 41.3± ; 6.6 cm, 34.4± ; 3.6 cm, 29.0± ; 3.8 cm ; HOP: 52.5± ; 4.8 cm, 48.6± ; 4.3 cm, 41.8± ; 5.2 cm ; SLJ: 276.0± ; 16.1 cm, 255.6± ; 11.8 cm, 231.5± ; 11.9 cm ; for S, S4 and MD respectively). The analysis of variance revealed significant differences between 100 m, 400 m and middle distance runners (p< 0.01). The only no significant differences between S and S4 were in the HOP test and between S4 and MD runners in the SJ, CMJL and CMJD tests. Discussion and conclusions The results of this study indicate the specificity of explosive strength and leg stiffness regarding the considered running events, which increase significantly with the increase in running speed for a specific event.

track and field ; different running events ; explosive strength ; biomechanics

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