Leena Paavolainen

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%.

Fatigue during a 5-km running time trial.

This study investigated fatigue-induced changes in neuromuscular and stride characteristics during and immediately after the 5-km running time trial. Eighteen well-trained male distance runners performed a maximal 20-m sprint test and maximal voluntary contraction (MVC) in a leg press machine before and immediately after the 5-km running time trial. In all the tests the EMG of five lower limb muscles was measured. The results of the present study showed that muscle fatigue measured in maximal exercises like 20-m sprint and MVC are not related to the fatigue induced changes during the 5-km time trial. The fatigue in the 20-m sprint test was related to the maximal 20-m pretest velocity (r=0.58, p<0.05), but the velocity loss during the 5-km time trial was inversely related to 5-km performance (r= - 0.60, p<0.05) and training volume (r= - 0.58, p<0.05). It was concluded that the fatigue in 5-km running measured pre- and postexercise at maximal effort is more related to sprint performance rather than endurance performance, but the fatigue measured during the 5-km running is related to endurance performance and factors affecting pacing strategy.

Muscle power factors and VO2max as determinants of horizontal and uphill running performance

This study was carried out to investigate the importance of maximal oxygen uptake (VO2max) and so‐called muscle power factors relating to neuromuscular and anaerobic characteristics as determinants of peak horizontal and uphill treadmill running velocity (Vmax). Muscle power factors were measured as peak velocity (VMART) and blood lactate concentration (BlaMART) in a maximal anaerobic running test and as maximal 30‐m run velocity (V30m). Seven middle‐distance runners, eight triathletes and eight cross‐country skiers performed an incremental VO2max‐test at horizontal (subscript max0) and 7° uphill (subscript max7) and the MART at 3° uphill on a treadmill and V30m‐test on a track. The MART consisted of n  ·  20‐s runs with a 100‐s recovery between the runs and the velocity was increased by 0.41 m  ·  s−1 for each consecutive run until exhaustion. At 0° Vmax was significantly higher but VO2max, ventilation and Bla were significantly lower than at 7° inclination. Vmax0 correlated with VMART (r=0.85, P<0.001), Blamax0 (r=0.49, P<0.05) and V30m (r=0.78, P<0.001) but not with VO2max0. Vmax7 correlated with VO2max7 (r=0.78, P<0.001), VMART (r=0.61, P<0.01) and V30m (r=0.53, P<0.05). VMART correlated with BlaMART (r=0.71, P<0.01) and V30m (r=0.96, P<0.001) but not with VO2max0 or VO2max7. Middle‐distance runners had a significantly (P<0.001) higher Vmax0, VMART, BlaMART and V30m than triathletes and cross‐country skiers, but no significant differences were found between the three groups in VO2max0, VO2max7 or Vmax7. We conclude that so‐called muscle power factors, e.g. VMART, V30m and BlaMART, contribute to peak treadmill running performance and especially to horizontal running performance and that VO2max contributes more to uphill than horizontal running performance.

Effects of explosive type strength training on physical performance characteristics in cross-country skiers

SummaryTo investigate the effects of a combination of simultaneous strength and endurance training on selected neuromuscular and aerobic performance characteristics seven male cross-country skiers underwent training for a period of 6 weeks. The experimental group trained 6–9 times per week with a programme consisting of 34% explosive type strength training and 66% endurance training during the first 3 weeks of the experiment and 42% and 58% respectively during the last 3 weeks of the experiment. The total volume of training of the control group (eight skiers) was of the same magnitude but consisted of 85% pure endurance training and 15% endurance type strength training. The experimental training regime resulted in specific changes in neuromuscular performance. This was demonstrated by improvements (P<0.01) in the maximal heights of rise of the centre of gravity in the squat and countermovement jumps. A significant decrease (P<0.05) took place also in the time of rapid isometric force production during experimental training, while no changes occurred in the maximal force of the trained muscles. Aerobic performance characteristics of the experimental group did not change during the experimental training period. No significant changes occurred in neuromuscular or aerobic performance characteristics in the control group. These findings indicated that training-induced improvements in explosive force production may not be fully inhibited by this kind of aerobic training. They also suggested that endurance athletes could undertake explosive type strength training programmes without a concomitant reduction in aerobic capacity, if the overall loading of training were within predefined limits.

Neuromuscular characteristics and fatigue in endurance and sprint athletes during a new anaerobic power test

AbstractThe 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 (

Neuromuscular adaptations during concurrent strength and endurance training versus strength training.

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Neuromuscular characteristics and fatigue during 10 km running.

max), anaerobic and aerobic thresholds were determined in the