Running economy (RE) is an important factor for the performance in distance running. Various authors attempted to individuate the biomechanical characteristics of economic runners (Williams 1987, Heise 2001) but the results are inconsistent among the studies. The aim of this work is to analyse the relationships between RE and selected kinematic indices in middle-distance runners. On a track, RE was measured as submaximal steady-state VO2 at four different speeds (60, 70, 80 and 90% of individual vVO2max) in 10 sub-elite middle distance runners (25.822.57 ys, 175.94.9 cm, 66.25.8 kg, 68.6 4.32 mlminkg-1). According to their RE, the subjects were divided into economic (E), intermediate (I) and non-economic (NE). At each speed, 30 different indices of lower limb kinematics were obtained through video analysis. Non parametric ANOVAs were performed to analyse the differences among the three categories for each of the 30 kinematic variables. Significance was set at p<0.05. The maximum knee angle during the support phase was significantly more acute (p<0.05) in E (137±2.4 deg) vs. both I (140±2.3 deg) and NE (142±1.8 deg). An analogous trend appeared for the total plantarflexion excursion during the support phase, being higher in E (36±4.7 deg) vs. I (33±3.8 deg) and NE (32±6.2 deg). Also peak plantarflexion velocity resulted higher in E (353±26.3 deg•s-1), than in I (329±28.1 deg•s-1) and NE (326±40.4 deg•s-1). These results may be explained considering that a not excessive rigidity of the musculotendineous system at the ankle and the knee joints may result in lower force production and thus energy savage. These findings are in agreement with Williams (1987). In conclusion, the importance for an economic running technique of the three parameters found to differentiate between RE levels may be claimed. REFERENCES • HEISE GD et al. (2001). Are variations in running economy in humans associated with ground reaction force characteristics? Eur J Appl Physiol. 84 :438-442 • WILLIAMS KR et al. (1987). Relationship between running mechanics, running economy, and performance. J Appl Physiol. 63:1236-1245
Relationships between running economy and selected kinematic parameters in middle distance runners / Merni F.; Di Michele R.. - STAMPA. - (2008), pp. 7-7. (Intervento presentato al convegno Workshop Congiunto IIM - SISMES tenutosi a Siena nel 31 ottobre 2008).
Relationships between running economy and selected kinematic parameters in middle distance runners
MERNI, FRANCO;DI MICHELE, ROCCO
2008
Abstract
Running economy (RE) is an important factor for the performance in distance running. Various authors attempted to individuate the biomechanical characteristics of economic runners (Williams 1987, Heise 2001) but the results are inconsistent among the studies. The aim of this work is to analyse the relationships between RE and selected kinematic indices in middle-distance runners. On a track, RE was measured as submaximal steady-state VO2 at four different speeds (60, 70, 80 and 90% of individual vVO2max) in 10 sub-elite middle distance runners (25.822.57 ys, 175.94.9 cm, 66.25.8 kg, 68.6 4.32 mlminkg-1). According to their RE, the subjects were divided into economic (E), intermediate (I) and non-economic (NE). At each speed, 30 different indices of lower limb kinematics were obtained through video analysis. Non parametric ANOVAs were performed to analyse the differences among the three categories for each of the 30 kinematic variables. Significance was set at p<0.05. The maximum knee angle during the support phase was significantly more acute (p<0.05) in E (137±2.4 deg) vs. both I (140±2.3 deg) and NE (142±1.8 deg). An analogous trend appeared for the total plantarflexion excursion during the support phase, being higher in E (36±4.7 deg) vs. I (33±3.8 deg) and NE (32±6.2 deg). Also peak plantarflexion velocity resulted higher in E (353±26.3 deg•s-1), than in I (329±28.1 deg•s-1) and NE (326±40.4 deg•s-1). These results may be explained considering that a not excessive rigidity of the musculotendineous system at the ankle and the knee joints may result in lower force production and thus energy savage. These findings are in agreement with Williams (1987). In conclusion, the importance for an economic running technique of the three parameters found to differentiate between RE levels may be claimed. REFERENCES • HEISE GD et al. (2001). Are variations in running economy in humans associated with ground reaction force characteristics? Eur J Appl Physiol. 84 :438-442 • WILLIAMS KR et al. (1987). Relationship between running mechanics, running economy, and performance. J Appl Physiol. 63:1236-1245I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
