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Neuromuscular characteristics and maximal velocity while running are related in well trained endurance athletes. Male athletes were tested on an indoor 5 km track and a treadmill running at a constant velocity, and their oxygen intake and peak performance were measured. Maximal velocity during such tests can measure muscle power in endurance athletes.

To investigate the effects of simultaneous explosive-strength and endurance training on physical performance characteristics, 10 experimental (E) and 8 control (C) endurance athletes trained for 9 wk. The total training volume was kept the same in both groups, but 32% of training in E and 3% in C was replaced by explosive-type strength training. A 5-km time trial (5K), running economy (RE), maximal 20-m speed (V20 m), and 5-jump (5J) tests were measured on a track. Maximal anaerobic (MART) and aerobic treadmill running tests were used to determine maximal velocity in the MART (VMART) and maximal oxygen uptake (V˙o2 max). The 5K time, RE, andVMARTimproved (P< 0.05) in E, but no changes were observed in C.V20 mand 5J increased in E (P< 0.01) and decreased in C (P< 0.05).V˙o2 maxincreased in C (P< 0.05), but no changes were observed in E. In the pooled data, the changes in the 5K velocity during 9 wk of training correlated (P< 0.05) with the changes in RE [O2uptake (r= −0.54)] andVMART(r= 0.55). In conclusion, the present simultaneous explosive-strength and endurance training improved the 5K time in well-trained endurance athletes without changes in theirV˙o2 max. This improvement was due to improved neuromuscular characteristics that were transferred into improvedVMARTand running economy.

The purpose of this study was to investigate neuromuscular and energy performance characteristics of anaerobic power and capacity and the development of fatigue. Ten endurance and ten sprint athletes performed a new maximal anaerobic running power test (MARP), which consisted ofn x 20-s runs on a treadmill with 100-s recovery between the runs. Blood lactate concentration [la−]b was measured after each run to determine submaximal and maximal indices of anaerobic power (P3mmol·1−1,P5mmol·1−1,P10mmol·1−1andPmax) which was expressed as the oxygen demand of the runs according to the American College of Sports Medicine equation: the oxygen uptake (ml·kg−1·min−1)=0.2·velocity (m·min−1) +0.9·slope of treadmill (frac)·velocity (m·min−1)+3.5. The height of rise of the centre of gravity of the counter movement jumps before (CMJrest) and during (CMJ) the MARP test, as well as the time of force production (tF) and electromyographic (EMG) activity of the leg muscles of CMJ performed after each run were used to describe the neuromuscular performance characteristics. The maximal oxygen uptake ( max), anaerobic and aerobic thresholds were determined in the max test, which consisted ofn x 3-min runs on the treadmill. In the MARP-testPmax did not differ significantly between the endurance [116 (SD 6) ml·kg−1·min−1] and sprint [120 (SD 4) ml·kg−1·min−1] groups, even though CMJrest and peak [la−]b were significantly higher and max was significantly lower in the sprint group than in the endurance group and CMJrest height correlated withPmax (r=0.50,P<0.05). The endurance athletes had significantly higher mean values ofP3mmol·1−1andP5mmol·1−1[89 (SD 7) vs 76 (SD 8) ml·kg−1·min−,P<0.001 and 101 (SD 5) vs 90 (SD 8) ml·kg−1·min−1,P<0.01. Significant positive correlations were observed between theP3mmol·l−1and max, anaerobic and aerobic thresholds. In the sprint group CMJ and the averaged integrated iEMG decreased andtF increased significantly during the MARP test, while no significant changes occurred in the endurance group. The present findings would suggest thatPmax reflected in the main the lactacid power and capacity and to a smaller extent alactacid power and capacity. The duration of the MARP test and the large number of CMJ may have induced considerable energy and neuromuscular fatigue in the sprint athletes preventing them from producing their highest alactacidPmax at the end of the MARP test. Due to lower submaximal [la−]b (anaerobic sprinting economy) the endurance athletes were able to reach almost the samePmax as the sprint athletes.

NUMMELA, A., H. RUSKO, and A. MERO. EMG activities and ground reaction forces during fatigued and nonfatigued sprinting. Mad. Sci. Sports Exerc., Vol. 26, No. 5, pp. 605–609, 1994. The present study was designed to investigate EMG activities and ground reaction forces during fatigued and nonfatigued running. Ten male sprint runners volunteered to run a maximal 20-m speed test, a 400-m time trial, and submaximal 20-m runs at the average speed of the first 100 in of the 400 m. During the latter stage of each run, ground reaction forces and EMG activity of four leg muscles were recorded. EMG activities were time averaged during three phases of running: preactivation, braking, and propulsion phase. The resultant ground reaction forces both in the braking (P< 0.001) and in the propulsion phase (P< 0.01) were greater in the maximal and submaximal 20 m than at the end of the 400 m. The averaged EMG during the braking phase (P< 0.01) and during the total ground phase (P< 0.05) was smaller in the submaximal 20 m than at the end of the 400 m. On the other hand the averaged EMG was greater during the maximal 20 m than at the end of the 400 m during the propulsion phase (P< 0.001) and during the total ground phase (P< 0.05). In addition, the more the prcactivity increased the less the resultant ground reaction force decreased in the braking phase during the 400 m run (r = 0.77, P< 0.05). It was concluded that the role of the increased neural activation was to compensate for muscular fatigue and the preactivation had an important role in maintaining force production during the 400-m run. In addition, the fatigue was different in each working muscle.