Neuromuscular Characteristics and Fatigue During 10 km Running

Abstract

This study investigated neuromuscular characteristics and fatigue during 10 km running (10 K) performance in well-trained endurance athletes with different distance running capability. Nine high (HC) and ten low (LC) caliber endurance athletes performed the 10 K on a 200 m indoor track, constant velocity lap (CVL, 4.5 m x s(-1)) 5 times during the course of the 10 K and maximal 20 m speed test before (20 m(b)) and after (20 m(a)) the 10 K. Running velocity (V), ground contact times (CT), ground reaction forces (F) and electromyographic activity (EMG) of the leg muscles (vastus lateralis; VL, biceps femoris; BF, gastrocnemius; GA) were measured during 20 m(b), 20 m(a), and CVLs. The 10 K times differed (p<0.001) between HC and LC (36.3+/-1.2 and 39.2+/-2.0 min, respectively) but no differences were observed in 20 m(b) velocity. The 10 K led to significant (p<0.05) decreases in V, F and integrated EMG (IEMG) and increases in CTs of 20 m(a) in both groups. No changes were observed in HC or LC in F and IEMG during the CVLs but HC showed shorter (p<0.05) mean CT of CVLs than LC. A significant correlation (r = -0.56, p<0.05) was observed between the mean CT of CVLs and velocity of 10 K (V10K). Pre-activity of GA in relation to the IEMG of the total contact phase during the CVLs was higher (p<0.05) in HC than LC. The relative IEMGs of VL and GA in the propulsion phase compared to the IEMG of the 20 m(b) were lower (p<0.05) in HC than LC. In conclusion, marked fatigue took place in both HC and LC during the 10 K but the fatigue-induced changes in maximal 20 m run did not differentiate endurance athletes with different V10K. However, a capability to produce force rapidly throughout the 10 K accompanied with optimal preactivation and contact phase activation seem to be important for 10 km running performance in well trained endurance athletes.

Altered neuromuscular control of leg stiffness following soccer-specific exercise

“…Preactivation levels have been shown to reduce in sprints performed after a 10 km run (Paavolainen et al 1999) and preactivation and the short-latency stretch-reflex are reduced during rebounds completed post marathon running (Avela and Komi 1998;Komi and Gollhofer 1997). In the present study changes in stiffness following exercise were strongly related to changes in feedforward activity and the short-latency stretch-reflex of the extensor muscles were strongly related to changes in CoMd.…”

Lower-Body Determinants of Running Economy in Male and Female Distance Runners

“…However, our results suggest that most neuromuscular characteristics, at least those measured in this study, have an unclear or small relationship with running economy. In previous studies, the timing and amplitude of muscle activity has shown the most consistent association with running economy (16,33,44,47,48). Measurements of electromyographic muscle activity were beyond the scope of this study, but on greater inspection, most of the previous studies indicate that greater muscle activity before and in the initial phase of ground contact may enhance running economy by increasing leg stiffness and maximizing exploitation of stored elastic energy.…”

Constant versus variable-intensity during cycling: effects on subsequent running performance

“…In this theoretical context where the central command in the motor cortex is perceived as a sense of effort, the determinants of variable cycling exercise in our study might include the sense of effort and other sensations such as muscle pain which become more intense than is tolerable (StClair Gibson and Noakes 2004). Furthermore, from running studies it has been reported that other neuromuscular factors may also be important determinants of endurance running performance (Nummela et al 2006;Paavolainen et al 1999). Paavolainen et al (1999) have shown that a better performance in the 10 km time trial is related to higher pre-activation of the working muscles, associated with shorter contact times throughout the run.…”

“…Furthermore, from running studies it has been reported that other neuromuscular factors may also be important determinants of endurance running performance (Nummela et al 2006;Paavolainen et al 1999). Paavolainen et al (1999) have shown that a better performance in the 10 km time trial is related to higher pre-activation of the working muscles, associated with shorter contact times throughout the run. Recently, Nummela et al (2006) reported that the impaired performance during a 5 km time trial is associated with a decreased pre-activation of lower limb muscles (from EMG measurements during the 100 ms before ground contact) and higher total ground contact times.…”