Ari Nummela

Neuromuscular characteristics and muscle power as determinants of 5-km running performance

PURPOSE The purpose of this study was to investigate neuromuscular characteristics and muscle power as determinants of distance running performance. METHODS Seventeen male endurance athletes performed a 5-km time trial (5K) that included three separate constant-velocity 200-m laps during the course and a maximal 20-m speed (V20m) test on an indoor track, and running economy (RE) tests on a treadmill and on the track. Maximal anaerobic (MART) and aerobic running tests on the treadmill were used to determine maximal velocity in the MART (VMART), maximal oxygen uptake (VO2max), peak treadmill performance (VO2max demand), and respiratory compensation threshold (RCT). RESULTS Velocity in the 5K (V5K) correlated positively (P < 0.05) with VO2max, VO2max demand, RCT, and RE, as well as with V20m and VMART. Regression analysis showed that RCT, track RE, and VMART were the most important determinants of V5K. V5K also correlated (P < 0.05) with contact times (CT) and stride rates in the maximal 20-m run (r = -0.49 and 0.58, respectively), as well as with the mean CT of the constant velocity laps during the 5K (r = -0.50). VMART correlated significantly with peak blood lactate concentration in MART (r = 0.59, P < 0.05), V20m (r = 0.87, P < 0.001), and CT in the maximal 20-m run (r = -0.61, P < 0.01). CONCLUSIONS We conclude that neuromuscular characteristics and VMART were related to 5-km running performance in well trained endurance athletes. Relationships between VMART and neuromuscular and anaerobic characteristics suggest that VMART can be used as a measure of muscle power in endurance athletes.

Concurrent endurance and explosive type strength training increases activation and fast force production of leg extensor muscles in endurance athletes.

The purpose of this experiment was to examine the effects of concurrent endurance and explosive strength training on electromyography (EMG) and force production of leg extensors, sport-specific rapid force production, aerobic capacity, and work economy in cross-country skiers. Nineteen male cross-country skiers were assigned to an experimental group (E, n = 8) or a control group (C, n = 11). The E group trained for 8 weeks with the same total training volume as C, but 27% of endurance training in E was replaced by explosive strength training. The skiers were measured at preand post training for concentric and isometric force-time parameters of leg extensors and EMG activity from the vastus lateralis (VL) and medialis (VM) muscles. Sport-specific rapid force production was measured by performing a 30-m double poling test with the maximal velocity (V30DP) and sport-specific endurance economy by constant velocity 2-km double poling test (CVDP) and performance (V2K) by 2-km maximal double poling test with roller skis on an indoor track. Maximal oxygen uptake (VO2max) was determined during the maximal treadmill walking test with the poles. The early absolute forces (0–100 ms) in the force-time curve in isometric action increased in E by 18 ± 22% (p < 0.05), with concomitant increases in the average integrated EMG (IEMG) (0–100 ms) of VL by 21 ± 21% (p < 0.05). These individual changes in the average IEMG of VL correlated with the changes in early force (r = 0.86, p < 0.01) in E. V30DP increased in E (1.4 ± 1.6%) (p < 0.05) but not in C. The V2K increased in C by 2.9 ± 2.8% (p < 0.01) but not significantly in E (5.5 ± 5.8%, p < 0.1). However, the steady-state oxygen consumption in CVDP decreased in E by 7 ± 6% (p < 0.05). No significant changes occurred in VO2max either in E or in C. The present concurrent explosive strength and endurance training in endurance athletes produced improvements in explosive force associated with increased rapid activation of trained leg muscles. The training also led to more economical sport-specific performance. The improvements in neuromuscular characteristics and economy were obtained without a decrease in maximal aerobic capacity, although endurance training was reduced by about 20%.

EMG activities and ground reaction forces during fatigued and nonfatigued sprinting.

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 m 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 preactivity 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.

A new method for the evaluation of anaerobic running power in athletes.

SummaryA new maximal anaerobic running power (MARP) test was developed. It consisted ofn · 20-s runs on a treadmill with a 100-s recovery between the runs. During the first run the treadmill speed was 3.97 m · s−1 and the gradient 5°. The speed of the treadmill was increased by 0.35 m · s−1 for each consecutive run until exhaustion. The height of counter-movement jumps and blood lactate concentration ([1a−]b) were measured after each run. Submaximal ([la− ] b = 3 mmol · l−1 and 10 mmol · l−1) and maximal speed and power (

Strength Training in Endurance Runners

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Heart rate variability in prediction of individual adaptation to endurance training in recreational endurance runners

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Effects of moderate and heavy endurance exercise on nocturnal HRV.

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