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PubMed2003

Oxygen uptake and ventilation during rowing and running in females and males.

This study evaluated if the ventilatory response to exercise is impaired by the cramp position of rowing. Maximal oxygen uptake (VO2max), maximal expiratory volume (VEmax), and maximal heart rate (HRmax) during rowing and running were compared in 55 males (age, mean +/- SD, 21 +/- 3 years; height 176 +/- 5 cm; body mass 72 +/- 6 kg) and 18 females (age 20 +/- 2 years; height 164 +/- 5 cm; body mass 61 +/- 4 kg). VEmax was larger during rowing than during running (males, 157 +/- 16 vs. 147 +/- 13 L min(-1); 114 +/- 9 vs. 105 +/- 11 L min(-1), P<0.01). Also VO2max was larger during rowing than during running (males, 4.5 +/- 0.5 vs. 4.3 +/- 0.4 L min(-1); females, 3.3 +/- 0.4 vs. 3.2 +/- 0.4 L min(-1), P<0.01). However, HRmax was lower during rowing than during running (males, 194 +/- 8 vs. 198 +/- 11 beats min(-1); females, 192 +/- 6 vs. 196 +/- 8 beats min(-1), P<0.05). VEmax was correlated to body mass and fat-free mass, as was VO2max. Thus, the oxygen pulse (VO2max/HRmax) was larger during rowing than during running, while the ventilatory equivalent for oxygen (VEmax/VO2max) was similar. We showed that bending the body during rowing does not seem to impair ventilation either in males or in females. The results indicate that VEmax and VO2max relate to body size and fat-free mass for both females and males. The findings indicate that the involvement of more muscles, the entrainment, and the body position during rowing facilitates ventilation and venous return and lowers maximal heart rate.

Adult↗

PubMed1999

Neuromuscular characteristics and fatigue during 10 km running.

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.

Adult↗

PubMed2000

The effects of a prolonged running exercise on strength characteristics.

The aim of this study was to examine concentric, isometric, and eccentric strength reductions in the quadriceps muscle following a prolonged running exercise. Before and after a 2 h run (28.4+/-1.4 km) peak torque (PT) of the knee extensors at angular velocities of -120, -90, -60, 0, 60, 120, 180, 240 degrees x s(-1) using an isokinetic dynamometer, electromyographic (EMG) activity of the vastus lateralis (VL) and vastus medialis (VM) muscles and height of a counter movement jump were recorded in twelve well-trained triathletes. Counter movement jump performances decreased by 10% and PT values were all significantly lower (p < 0.01) at each angular velocity following the run. The torque loss was significantly (p < 0.01) greater under eccentric contractions (from 18 to 21%) than under concentric ones (from 11 to 14%). EMG activity (RMS) was lower in both VL and VM muscles after the 2 h run but no difference existed in RMS losses between concentric and eccentric contractions. The present results demonstrate that 1) a prolonged running exercise more greatly affects eccentric force production in the quadriceps muscle, and 2) this specificity seems to be due to an impairment of the muscular contractile mechanism rather than a modification to the neural input.

Adult↗

PubMed2000

Measurements of rearfoot motion during running.

Excessive rearfoot motion is an important factor that has been linked to the development of injuries in running. Therefore, extensive research has been performed that to investigate the movement of the foot and factors that influence the degree of rearfoot motion. Several methodological procedures are available that indirectly determine the degree of rearfoot movement. High-speed film, high-speed video and opto-electric techniques have been used to analyse the posterior aspect of the heel counter of the shoe in the frontal plane to determine rearfoot motion at ground contact on a treadmill or during overground running. Recent studies used invasive pin methods to determine rearfoot motion during running under different conditions. Using a non-invasive approach, electrogoniometers have been used to quantify rearfoot motion. The purpose of this study was to explore the use of an in-shoe electrogoniometric method to investigate rearfoot motion during running in different running shoes. The results showed that rearfoot motion variables were lower using the in-shoe goniometer compared to a heel counter method. This confirms previous bone pin studies where significant lower eversion and eversion velocity values were revealed by the bone pins compared to the shoe counter markers. Thus, external measurements seem to overestimate rearfoot motion significantly. On the other hand, the in-shoe measurements revealed slightly lower GRF related values. As with any other shoe insert, an in-shoe device elevates the foot slightly and thus may influence the mechanical behaviour of the shoe.

Adult↗

PubMed2003

Physiological, subjective and performance effects of pseudoephedrine and phenylpropanolamine during endurance running exercise.

The aim of the study was to assess the effect of maximal therapeutic dosing of sympathomimetic amines found in over-the-counter (OTC) decongestant preparations on endurance running. Following familiarisation and a graded exercise test to determine maximal oxygen uptake (VO2 max), trained male runners (n = 8) completed four exercise sessions each separated by a minimum of one week. Each session was comprised of 20 min of sub-maximal treadmill running (70 % VO2 max) followed by a 5,000-m time trial on the treadmill under drug, placebo or control conditions. Drugs were administered in their commercial format over the 36-hour period prior to testing in the manufacturer's recommended maximal doses (i. e. 25 mg of phenylpropanolamine and 60 mg of pseudoephedrine four times daily). During sub-maximal endurance running no statistical differences were observed in heart rate, VO2, minute ventilation, respiratory exchange ratio, blood lactate, glucose or non-esterified fatty acids (NEFA) or ratings of perceived exertion with respect to the treatment administered. Similarly there were no statistical differences according to the condition during the 5,000-m running time trial, in terms of heart rate, ratings of perceived exertion, time of completion and pre and post exercise blood lactate, glucose or NEFA. The results indicate that in maximal, multiple therapeutic doses both pseudoephedrine or phenylpropanolamine as present in common OTC decongestant formulations do not affect, nor possess any ergogenic properties with regard to, endurance running.

Adult↗

PubMed2003

Change of required foot impact position during running to exhaustion on a treadmill.

In healthy human subjects running on a treadmill, measurements were made to determine how rapidly and precisely they were able to adjust the impact position of their feet using visual clues. Foot impact position was measured with force transducers at each corner of the treadmill. Required longitudinal positions were indicated by three lines of light ("target-lines"), projected transversely across the treadmill plate. Test runs were conducted until exhaustion at speeds exceeding the aerobic threshold (mean endurance time about 9 min; mean belt speed 12 km/h, mean inclination 6.9 %). During running, required foot positions were, at irregular intervals and during periods of 7 steps each, temporarily switched from the most posterior target-line (TL3) to one of the two more anterior ones (TL2 or TL1). The first change of foot impact position took place within about 175 - 225 ms after a switch from TL3 to TL2/TL1; this initial small change was in a direction opposite to that required. The total adjustment of foot impact position, as seen during 7 consecutive test steps, took place during at least 2 - 3 steps (0.8 - 1.2 s). Towards the end of the test run, with exhaustion approaching, the adjustment process became somewhat slower and showed an increasing lengthwise deficit. Our results demonstrate the existence of prolonged multi-step processes of motor adjustment during treadmill running plus a sensitivity of the foot placement process to time-on-task (when approaching exhaustion?).

Adult↗

PubMed2006

The consequences of swim, cycle, and run performance on overall result in elite olympic distance triathlon.

This study examined the consequences of performance in swim, cycle, and run phases on overall race finish in an elite "draft legal" Olympic distance (OD) triathlon. The subjects were 24 male athletes grouped by rank order into the top 50 % (n = 12) and bottom 50 % (n = 12) of the race population. Swimming velocity (m x s (-1)), cycling speed (km x h (-1)), and running velocity (m x s (-1)) were measured at regular intervals using a global positioning system, chip timing system, and video analysis. Actual rank after each stage and overall was obtained from the race results and video analysis. The top 50 % athletes overall swam faster over the first 400 m of the swim phase (p > 0.05). Their swim ranking was lower (p < 0.01) than the bottom 50 % athletes after this stage. There were no significant differences in actual race position between the groups after the cycle. However, the bottom 50 % athletes after the swim stage cycled faster (p < 0.01) at 13.4 km of the cycle. Speed at 13.4 km of the cycle stage was inversely correlated (r = 0.60, p < 0.01) to running performance. Performance (rank and velocity) in the running stage was highly correlated with overall race result (r = 0.86 and - 0.53, respectively, both p > 0.01). It appears that inferior swimming performance can result in a tactic that involves greater work in the initial stages of the cycle stage of elite OD racing, and may influence subsequent running performance.

Analysis of Variance↗

PubMed2006

The relationship between the lactate turnpoint and the time at VO2max during a constant velocity run to exhaustion.

The present investigation examined the relationship between the running velocity at the lactate turnpoint (vLTP) and the time at which VO2max can be sustained (TVO2max) during a continuous run to exhaustion at the minimal running velocity that elicits VO2max (vVO2max). Seven moderately-trained endurance runners undertook three tests on a treadmill. The first test was to determine vVO2max; the second to determine the time to exhaustion during a constant velocity run at vVO2max (Tlim vVO2max) and TVO2max; and the third to determine the vLTP. Pearson's correlation coefficient was used to determine the association between the vLTP (%vVO2max; i.e. the relative vLTP) and TVO2max, and between other selected physiological variables. Correlations between the relative vLTP and TVO2max, expressed as a percentage of T(lim vVO2max (the relative TVO2max; r=0.82), and between TVO2max and Tlim vVO2max (r=0.89), were significant at the p<0.05 level. All other correlations between selected measured physiological variables were found to be statistically insignificant. The main finding of this present study is that the relative vLTP demonstrated a significant positive correlation with the relative TVO2max. The physiological mechanism by which the lactate turnpoint may influence the relative TVO2max has not been elucidated, but may be due to a combination of decreasing the time to attain VO2max and increasing Tlim vVO2max. The present investigation has demonstrated that the lactate turnpoint may influence the relative time at which VO2max can be sustained during a continuous run to exhaustion at vVO2max, although further research is required to substantiate these findings.

Adult↗

PubMed1993

Exercise responses to in-line skating: comparisons to running and cycling.

A comparison of the physiological responses to in-line skating with the more traditional modes of exercise training has not been reported. The purpose of this study was to examine the physiological responses to in-line skating compared with running and cycling. Nine trained volunteers (2 male, 7 female) performed 3-6 submaximal (30-90% VO2max) workloads with each exercise mode. Oxygen uptake, heart rate and blood lactate were measured during each trial. Across the spectrum of oxygen uptakes studied, heart rate was higher with in-line skating than with cycling or running. At a lactate concentration of 4 mM, oxygen uptake was less for in-line skating and cycling than for running. Therefore, while in-line skating may be an effective mode of aerobic exercise, the training adaptations for in-line skating at 4 mM lactate may not be as great as for running, and at a given HR may be less than for running and cycling.

Adult↗

PubMed1991

Control of training in middle- and long-distance running by means of the individual anaerobic threshold.

It was examined in 24 highly trained endurance athletes (middle- and long-distance runners, triathletes) whether concrete training recommendations can be made for endurance training and a speed session program (5 x 1000 m with 4.5-min breaks) by means of incrementally graded treadmill exercise with determination of the individual anaerobic threshold (IAT). The intensities of the different training sessions were decided upon using percentages of speed at the IAT and controlled by lactate determinations. The endurance runs were differentiated by terrain gradation and the speed sessions by climatic conditions. There is a significant correlation between the behaviour of lactate during training sessions and the IAT or percentages of speed at the IAT determined on a treadmill (endurance run flat terrain: r = 0.79, n = 13, p less than 0.01; endurance run graded terrain: r = 0.72, n = 20, p less than 0.001; 5 x 1000 m under good conditions: r = 0.97, n = 9, p less than 0.001; 5 x 1000 m under poor conditions: r = 0.91, n = 7, p less than 0.001). Both terrain gradation (endurance runs) and poor climatic conditions (speed sessions) lead to a left shifting of the regression line with unchanged slope. Conclusively the IAT determined during a treadmill exercise allows a sufficiently precise control of training both for endurance runs performed with different intensities and for the 5 x 1000-m speed session program. However, the external conditions have to be considered in order to provide correct training recommendations.

Adult↗

PubMed1990

Gastric emptying with repeated drinking during running and bicycling.

The high prevalence of gastrointestinal complaints in long-distance runners makes the movements specific to this type of exercise suspected of causing a disruption of normal gastrointestinal function. Gastric emptying rate is one indicator thereof. In the present study trained volunteers performed similar repeated fluid ingestion tests while running and while bicycling for 80 min at 70% VO2max. Control tests at rest were also conducted. Two drinks containing carbohydrate were tested, one hypertonic, and one isotonic. Artificially sweetened water was used as a control. Gastric emptying rate of the isotonic drink, expressed as a percentage of the volume in the stomach at the beginning of each measurement period, did not differ between cycling and running during the first 40 min and was faster during cycling than during running between 40 and 80 min. With the hypertonic drink no differences between cycling and running were observed. In comparing gastric emptying rates after each sequential bolus, at rest, the isotonic drink was observed to maintain a high emptying rate, equal to that of water, whereas the hypertonic drink emptied more slowly after the first 20-min period. A similar pattern was observed during both running and cycling. The isotonic drink continued to empty quickly after the initial 20 min, whereas GE rate of the hypertonic drink decreased after the initial 20 min.

Adult↗

PubMed1990

Changes in plasma concentration of hypoxanthine and uric acid in man with short-distance running at various intensities.

The relationship between running intensity and the accumulation of hypoxanthine and uric acid in plasma was studied in four well-trained runners. The runners each performed several 800-m runs at different velocities, each run being performed on separate days. Venous blood samples were collected before and at regular intervals after the runs. The concentration of hypoxanthine and uric acid was determined with high performance liquid chromatography (HPLC) in plasma extracts. A marked increase in the plasma concentration of both hypoxanthine and uric acid occurred simultaneously at intensities corresponding to 110, 108, 115 and 107% of VO2max for subject a, b, c and d, respectively. The sudden sharp increase in plasma concentration of hypoxanthine and uric acid may indicate that at a certain level of running intensity ATP catabolism exceeds the rate of ATP regeneration from the normal metabolic pathways.

Adolescent↗

PubMed1998

Influence of one bout of intensive running on lymphocyte micronucleus frequencies in endurance-trained and untrained men.

Exercise induced chromosomal damage was evaluated in trained and untrained subjects, who performed treadmill running at 85% of maximal oxygen uptake for 30 min. The subjects had their peripheral blood taken before, immediately after and 30 min after the running test for the analysis of lymphocyte chromosomal damage that was evaluated by micronucleus assay. The blood samples were also subjected to X-ray irradiation in vitro to examine the modification of exercise induced chromosomal damage by a secondarily induced oxidative stress. Spontaneous chromosomal damage in lymphocytes did not significantly increase at least until 30 min after the running both in the trained and untrained subjects. However, the X-ray-induced chromosomal damage was significantly enhanced at 30 min after the running in the untrained group, but not in the trained group. The ratio of X-ray-induced/spontaneous chromosomal damage also tended to increase after the running only in the untrained group. These preliminary results suggest that intensive exercise induced very slight chromosomal damage only in the untrained group, which could be intensified by the secondarily induced oxidative stress.

Adult↗

PubMed1996

The validity of isokinetic knee extensor endurance measurements with reference to treadmill running capacities.

The validity of isokinetic knee extensor endurance measurements with reference to treadmill running capacities was investigated. Nine male elite middle-distance runners completed a test consisting of 100 repetitive maximal eccentric and 100 concentric knee extensor actions where peak torque (Nm) and work (J) were measured. On a different day, submaximal and maximal treadmill tests were performed. Stepwise regression analysis was applied to determine the isokinetic variables with the greatest influence on the selected treadmill running capacities, including submaximal oxygen uptake (VO(2)) and maximal blood lactate. Eccentric total work was significantly and negatively related to submaximal VO(2) at all three running velocities investigated (12, 14, and 15 km.h(-1)). The R(2) values ranged from 0.48-0.59 for V0(2) ml.kg(-0.75).min(-1), indicating that 48-59 % of the variability in VO(2) ml.kg(-0.75).min(-1) could be accounted for by eccentric total work. The corresponding R(2) values for VO in ml.kg(-1).min(-1) were 0.50-0.58. Concentric relative endurance was significantly and negatively related to maximal blood lactate (R(2) = 0.73). This study has shown that isokinetic knee extensor endurance measurements of eccentric total work and concentric relative endurance are substantially related to measures of treadmill running capacity, as expressed by submaximal V02 and maximal blood lactate. It is suggested that these isokinetic measures may be used to evaluate specified running capacities in male elite middle-distance runners.

Adult↗

PubMed1996

Effect of inclination on the results of the maximal anaerobic running test.

This study investigated the effect of treadmill inclination on the maximal anaerobic running test (MART). Ten male subjects ran a 20-m speed test on a track to determine the maximal running velocity (V20m) and performed three MARTs at the grades of 1 degree, 4 degrees and 7 degrees in a random order. Each MART included n 20-s sprints at gradually increased velocity and counter-movement jumps (CMJ) which were performed before and after the exhausting sprints. At each grade, the power (oxygen demand) of the sprints was determined by extrapolating the individual steady state oxygen uptake of three submaximal running velocities measured separately at the corresponding grades. Maximal power (Pmax), power at 10mM (P10mM) and 5 mM (P5mM) blood lactate levels as well as peak blood lactate concentration (peak BLa) were determined at each MART. The Pmax increased from 94.1 +/- 8.8 and 110.0 +/- 10.2 to 119.5 +/- 8.0 ml.kg-1.min-1 when the treadmill inclination increased from 1 degree and 4 degrees to 7 degrees, respectively (p < 0.001). P10mM and P5mM also increased with the inclination (p < 0.001). Correlation coefficients of the Pmax with CMJrest and V20m were 0.77 and 0.69 at the grade of 1 degree, 0.75 and 0.59 at the grade of 4 degrees, and 0.62 and 0.42 at the grade of 7 degrees, respectively. The increased peak BLa (p < 0.01) with the treadmill inclination suggests that lactic capacity was not completely used at the grades of 1 degree and 4 degrees. In conclusion, the maximal power increased with the grade of uphill running in the MART. Furthermore, the present results suggest that the importance of force and velocity components of the neuromuscular system decreased and the importance of metabolic component increased with the increased grade of the uphill running.

Adult↗

PubMed1983

Maximal aerobic capacity of Canadian schoolchildren: prediction based on age-related oxygen cost of running.

Timed distance runs were administered to a random sample of 2,683 schoolchildren aged 7--16 years. Oxygen uptake was then measured during level treadmill running over a range of submaximal speeds in a randomly selected subsample of 134 children with approximately equal representation according to age and sex. The VO2--running speed relationship was found to be related to age with the younger children having a greater VO2 per kg body weight than the older children when running at the same absolute speed. Based on the relationship found between measured VO2max and VO2max predicted according to field test performance, corrected for age-related differences in running efficiency, VO2max was predicted for all 2,683 children. When expressed per kg of body weight, VO2max was highest in girls at age 11 (approximately 44 ml/kg) and in boys at age 14 (approximately 54 ml/kg); however, differences among ages were nonsignificant. At all ages VO2max for the boys was significantly higher than that for the girls. At all ages, values were higher than those previously reported for Canadian schoolchildren.

Adolescent↗

PubMed1981

Onset of blood lactate accumulation and marathon running performance.

This study was designed to examine the interrelationships among endurance running performance (marathon), the exercise intensity at which the "onset of blood lactate accumulation" (OBLA) occurs training volume, and muscle fiber characteristics. In conjunction with Stockholm's Marathon (1979), 18 male subjects underwent a test to determine the relationship between treadmill running velocity and blood lactate accumulation. The velocity at which a blood lactate accumulation of 4 mmol x l-1 occurred was referred to as the VOBLA. The m. vastus lateralis was biopsied and muscle fiber type distribution (% slow twitch, ST) and capillary density determined. With marathon running velocity (VM) as the dependent variable, multiple regression analysis showed that VOBLA accounted for 92% of the variation in VM, and VOBLA plus training volume prior to the marathon accounted for 96% of this variation. All performance variables were positively correlated to % ST muscle fiber distribution (r = 0.55-0.69) and capillary density (r = 052-0.63). Thus, marathon running performance was closely related to VOBLA and to the ability to run at a pace close to that velocity during the race. These properties were in turn related to % ST, capillary density, and training volume.

Adult↗

PubMed2002

The influence of exercise duration at VO2 max on the off-transient pulmonary oxygen uptake phase during high intensity running activity.

The purpose of this study was to examine the influence of time run at maximal oxygen uptake (VO2 max) on the off-transient pulmonary oxygen uptake phase after supra-lactate threshold runs. We hypothesised: 1) that among the velocities eliciting VO2 max there is a velocity threshold from which there is a slow component in the VO2-off transient, and 2) that at this velocity the longer the duration of this time at VO2 max (associated with an accumulated oxygen kinetics since VO2 can not overlap VO2 max), the longer is the off-transient phase of oxygen uptake kinetics. Nine long-distance runners performed five maximal tests on a synthetic track (400 m) while breathing through the COSMED K4b2 portable, telemetric metabolic analyser: i) an incremental test which determined VO2 max, the minimal velocity associated with VO2 max (vVO2 max) and the velocity at the lactate threshold (vLT), ii) and in a random order, four supra-lactate threshold runs performed until exhaustion at vLT + 25, 50, 75 and 100% of the difference between vLT and vVO2 max (vdelta25, vdelta50, vdelta75, vdelta100). At vdelta25, vdelta50 (= 91.0 +/- 0.9% vVO2 max) and vdelta75, an asymmetry was found between the VO2 on (double exponential) and off-transient (mono exponential) phases. Only at vdelta75 there was at positive relationship between the time run at VO2 max (%tlimtot) and the VO2 recovery time constant (Z = 1.8, P = 0.05). In conclusion, this study showed that among the velocities eliciting VO2 max, vdelta75 is the velocity at which the longer the duration of the time at VO2 max, the longer is the off-transient phase of oxygen uptake kinetics. It may be possible that at vdelta50 there is not an accumulated oxygen deficit during the plateau of VO2 at VO2 max and that the duration of the time at VO2 max during the exhaustive runs at vdelta100, could be too short to induce an accumulating oxygen deficit affecting the oxygen recovery.

Adult↗