Assessment of middle-distance running performance in sub-elite young runners using energy cost of running

The purpose of this study was to assess the validity of v _amax as an indicator of middle-distance running performance in sub-elite young runners, _amax being defined as the quotient maximal oxygen uptake (V˙O _2max) divided by the net energy cost of running (C _r) on a treadmill at a submaximal running velocity (280 m · min⁻¹). The V˙O _2max, ventilatory threshold, _amax, and C _r were assessed in 39 young male sub-elite runners having only small variations in performance level. The relationship between each variable and running performance (at 1500 m, 3000 m, and 5000 m) was evaluated. A trend toward a negative correlation existed between C _r and performance although this was not significant. The V˙O _2max and _amax were significantly related to performance. The _amax accounted for around 50% of the variability in performance whereas other physiological variables selected in this study were responsible, at best, for approximately 39%. The results presented in this study suggested that _amax was a useful indicator of middle-distance running performance in sub-elite young runners with similar performance levels as well as in top elite athletes. Accepted: 19 August 1997     

Effects of dynamic stretching on energy cost and running endurance performance in trained male runners

The purpose of this study was to examine the effects of dynamic stretching on running energy cost and endurance performance in trained male runners. Fourteen male runners performed both a 30-minute preload run at 65% VO2max and a 30-minute time trial to assess running energy cost and performance, respectively. The subjects repeated both the trials after either 15 minutes of dynamic stretching (i.e., experimental condition) or quiet sitting (i.e., control condition) while the order was balanced between the subjects to avoid any order effect. The total calories expended were determined for the 30-minute preload run, whereas the distance covered was measured in the time trial. Average resting VO2 increased significantly (p < 0.05) after dynamic stretching (prestretch: 6.2 ± 1.7 vs. poststretch: 8.4 ± 2.1 ml·kg(-1)·min(-1)) but not during the quiet-sitting condition. Caloric expenditure was significantly higher during the 30-minute preload run for the stretching (416.3 ± 44.9 kcal) compared with that during the quiet sitting (399.3 ± 50.4 kcal) (p < 0.05). There was no difference in the distance covered after quiet sitting (6.3 ± 1.1 km) compared with that for the stretching condition (6.1 ± 1.3 km). These findings suggest that dynamic stretching does not affect running endurance performance in trained male runners.     

The effects of resistance training on endurance distance running performance among highly trained runners: a systematic review

The current perception among highly competitive endurance runners is that concurrent resistance and endurance training (CT) will improve running performance despite the limited research in this area. The purpose of this review was to search the body of scientific literature for original research addressing the effects of CT on distance running performance in highly competitive endurance runners. Specific key words (including running, strength training, performance, and endurance) were used to search relevant databases through April 2007 for literature related to CT. Original research was reviewed using the Physiotherapy Evidence Database (PEDro) scale. Five studies met inclusion criteria: highly trained runners (>or= 30 mile x wk(-1) or >or= 5 d x wk(-1)), CT intervention for a period >or= 6 weeks, performance distance between 3K and 42.2K, and a PEDro scale score >or= 5 (out of 10). Exclusion criteria were prepubertal children and elderly populations. Four of the five studies employed sport-specific, explosive resistance training, whereas one study used traditional heavy weight resistance training. Two of the five studies measured 2.9% improved performance (3K and 5K), and all five studies measured 4.6% improved running economy (RE; range = 3-8.1%). After critically reviewing the literature for the impact of CT on high-level runners, we conclude that resistance training likely has a positive effect on endurance running performance or RE. The short duration and wide range of exercises implemented are of concern, but coaches should not hesitate to implement a well-planned, periodized CT program for their endurance runners.     

The energetics of middle-distance running

In order to assess the relative contribution of aerobic processes to running velocity (v), 27 male athletes were selected on the basis of their middle-distance performances over 800, 1500, 3000 or 5000 m, during the 1987 track season. To be selected for study, the average running velocity (v) corresponding to their performances had to be superior to 90% of the best French v of the season. Maximum O2 consumption (VO2max) and energy cost of running (C) had been measured within the 2 months preceding the track season, which, together with oxygen consumption at rest (VO2rest) allowed us to calculate the maximal v that could be sustained under aerobic conditions: vamax = (VO2max - VO2rest) x C-1. The treadmill running v corresponding to a blood lactate of 4 mmol.l-1 (vla4), was also calculated. In the whole group, C was significantly related to height (r = -0.43; P less than 0.03). Neither C nor VO2max (with, in this case, the exception of the 3000 m athletes) were correlated to v. On the other hand, vamax was significantly correlated to v over distances longer than 800 m. These v were also correlated to vla4. However vla4 occurred at 87.5% SD 3.3% of vamax, this relationship was interpreted as being an expression of the correlation between vamax and v. Calculation of vamax provided a useful means of analysing the performances. At the level of achievement studied, v sustained over 3000 m corresponded to vamax.(ABSTRACT TRUNCATED AT 250 WORDS)     

The effect of a high carbohydrate diet on running performance during a 30-km treadmill time trial

The purpose of the present study was to examine the influence of a high carbohydrate diet on running performances during a 30-km treadmill time trial. Eighteen runners (12 men and 6 women) took part in this study and completed a 30-km time trial on a level treadmill without modifying their food intake (trial 1). The runners were then randomly assigned to a control or a carbohydrate (CHO) group. The CHO group supplemented their normal diets with additional carbohydrate in the form of confectionery products during the 7 days before trial 2; the control group matched the increased energy intake of the CHO group by consuming additional fat and protein. The mean (SEM) carbohydrate intake of both groups was 334 (22) g before trial 1, after which the CHO group consumed 566 (29) g.day-1 for the first 3 days and 452 (26) g.day-1 for the remaining 4 days of recovery. Although there was no overall difference between the performance times for the two groups during trial 2, the CHO group ran faster during the last 5 km of trial 2 than during trial 1 [3.64 (0.24) m.s-1 vs 3.44 (0.26) m.s-1; P less than 0.05]. Furthermore, the 6 men in the CHO group ran the 30 km faster after carbohydrate loading [131.0 (5.4) min vs 127.4 (4.9) min; P less than 0.05], whereas there was no such improvement in times of the men in the control group.(ABSTRACT TRUNCATED AT 250 WORDS)     

Prerequisites in distance running performance of female runners

We investigated which attribute or what combination of attributes would best account for distance running performance of female runners. The subjects were 30 well-trained female distance runners, aged 19 to 23 years. Anthropometric and body composition characteristics, pulmonary function characteristics, blood properties, and cardiorespiratory function characteristics were measured at rest or during submaximal and maximal exercise. Analyses of the data showed that the relationship of oxygen uptake corresponding to lactate threshold (VO2T, ml.kg-1.min-1) with each distance running performance was substantially higher as compared with the relationship of other independent variables including maximal oxygen uptake (VO2max). Furthermore, multiple regression analysis indicated that running performances in 3,000m, 5,000m, and 10,000m are best accounted for by a combination of VO2/LT (X1), fat-free weight (X2), and/or mean corpuscular volume (X3). A multiple regression equation for predicting the 5,000m (Y, s) running performance was formulated as Y = -14.75X1-3. 03X2-5.79X3 + 2282.1. We suggest that VO2max would not stand alone as a decisive factor of distance running success in female runners, and that the distance running performance could be better accounted for by a combination of several attributes relating to lactate threshold, body composition, and/or hematological status. The linear regression of the predicted running performance on the actually measured running performance can be accepted in the range of 986-1197s.     

Aerobic and anaerobic contribution to Wingate test performance in sprint and middle-distance runners

We investigated the aerobic and anaerobic contributions to performance during the Wingate test in sprint and middle-distance runners and whether they were related to the peak aerobic and anaerobic performances determined by two commonly used tests: the force-velocity test and an incremental aerobic exercise test. A group of 14 male competitive runners participated: 7 sprinters, aged 20.7 (SEM 1.3) years, competing in 50, 100 and 200-m events and 7 middle-distance runners, aged 20.0 (SEM 1.0) years, competing in 800, 1,000 and 1,500 m-events. The oxygen uptake ( ) was recorded breath-by-breath during the test (30 s) and during the first 20 s of recovery. Blood samples for venous plasma lactate concentrations were drawn at rest before the start of the test and during the 20-min recovery period. During the Wingate test mean power ( ) was determined and three values of mechanical efficiency, one individual and two arbitrary, 16% and 25%, were used to calculate the contributions of work by aerobic ( _{aer,ind,16%,25%}) and anaerobic ( _{an,ind,16%,25%}) processes. Peak anaerobic power ( _an,peak) was estimated by the force-velocity test and maximal aerobic energy expenditure ( _aer,peak) was determined during an incremental aerobic exercise test. During the Wingate test, the middle-distance runners had a significantly greater than the sprinters (P < 0.001), who had significantly greater venous plasma lactate concentrations (P < 0.001). Moreover, _{aer,ind,16%,25%} were also significantly higher (P < 0.05) in the middle-distance runners [ _aer,ind 45 (SEM 4) % vs 28 (SEM 2) %; _aer,16% 30 (SEM 3) % vs 19 (SEM 2) %; _aer,25% 46 (SEM 3) % vs 29 (SEM 2)%]; _{an,ind,16%,25%} in the sprint runners (P < 0.05) [ _an,ind 72 (SEM 3) % vs 55 (SEM 4) %; _an,16% 81 (SEM 2) % vs 70 (SEM 3) %; _an,25% 71 (SEM 2) % vs 54 (SEM 3) %]. The _aer,ind/ _aer,peak and × _an,ind/ _an,peak ratios, however, were not significantly different between the two groups of athletes. These results would indicate that the sprinters and middle-distance runners used preferentially a metabolic system according to their speciality. Nevertheless, under the conditions of its experiment, they seemed to rely on the same percentage of both peak anaerobic and peak aerobic performance for a given exercise task.     

The effects of static stretching on running economy and endurance performance in female distance runners during treadmill running

Stretching can lead to decreased muscle stiffness and has been associated with decreased force and power production. The purpose of this study was to investigate the acute effects of static stretching (SS) on running economy and endurance performance in trained female distance runners. Twelve long distance female (30 ± 9 years) runners were assessed for height (159.4 ± 7.4 cm), weight (54.8 ± 7.2 kg), % body fat (19.7 ± 2.8%), and maximal oxygen consumption (VO2max: 48.4 ± 5.1 ml·kg(-1)·min(-1)). Participants performed 2 sessions of 60-minute treadmill runs following a randomly assigned SS protocol or quiet sitting (QS). During the first 30 minutes (running economy), expired gases, heart rate (HR), and rating of perceived exertion (RPE) were recorded while the participant ran at 65% VO2max. During the final 30 minutes (endurance performance), distance covered, speed, HR, and RPE were recorded while the participant attempted to cover as much distance as possible. Repeated measures analyses of variance were performed on the data. Significance was accepted at p < 0.05. The SS measured by sit-and-reach increased flexibility (SS: 29.8 ± 8.3 vs. QS: 33.1 ± 8.1 cm) but had no effect on running economy (VO2: 33.7 ± 3.2 vs. 33.8 ± 2.3 ml·kg(-1)·min(-1)), calorie expenditure (270 ± 41 vs. 270 ± 41 kcal), HR (157 ± 10 vs. 160 ± 12 b·min(-1)), or endurance performance (5.5 ± 0.6 vs. 5.5 ± 0.7 km). These findings indicated that stretching did not have an adverse effect on endurance performance in trained women. This suggests that the performance decrements previously associated with stretching may not occur in trained women.     

Short-term plyometric training improves running economy in highly trained middle and long distance runners

Fifteen highly trained distance runners VO(2)max 71.1 +/- 6.0 ml.min(-1).kg(-1), mean +/- SD) were randomly assigned to a plyometric training (PLY; n = 7) or control (CON; n = 8) group. In addition to their normal training, the PLY group undertook 3 x 30 minutes PLY sessions per week for 9 weeks. Running economy (RE) was assessed during 3 x 4 minute treadmill runs (14, 16, and 18 km.h(-1)), followed by an incremental test to measure VO(2)max. Muscle power characteristics were assessed on a portable, unidirectional ground reaction force plate. Compared with CON, PLY improved RE at 18 km.h(-1) (4.1%, p = 0.02), but not at 14 or 16 km.h(-1). This was accompanied by trends for increased average power during a 5-jump plyometric test (15%, p = 0.11), a shorter time to reach maximal dynamic strength during a strength quality assessment test (14%, p = 0.09), and a lower VO(2)-speed slope (14%, p = 0.12) after 9 weeks of PLY. There were no significant differences in cardiorespiratory measures or VO(2)max as a result of PLY. In a group of highly-trained distance runners, 9 weeks of PLY improved RE, with likely mechanisms residing in the muscle, or alternatively by improving running mechanics.     

Benefits of caffeine ingestion on sprint performance in trained and untrained swimmers

The influence of specific training on benefits from caffeine (Caf) ingestion was examined during a sprint test in a group of highly trained swimmers (T) and compared with the response of a group of untrained occasional swimmers (UT). Seven T and seven UT subjects swam freestyle two randomly assigned 2 x 100 m distances, at maximal speed and separated by 20 min of passive recovery, once after Caf (250 mg) and once after placebo (Pla) ingestion. Anaerobic capacity was assessed by the mean velocity (meters per second) during each 100 m and blood was sampled from the fingertip just before and 1, 3, 5, 7, and 9 min after each 100 m for resting and maximal blood lactate concentration ([la-]b,max) determination. The [la-]bmax was significantly enhanced by Caf in both T and UT subjects (P less than 0.01). However, only T subjects exhibited significant improvement in their swimming velocity (P less than 0.01) after Caf or any significant impairment during the second 100 m. In light of these results, it appears that specific training is necessary to benefit from the metabolic adaptations induced by Caf during supramaximal exercise requiring a high anaerobic capacity.     

Minimal effect of acute caffeine ingestion on intense resistance training performance

The primary aim of the study was to determine the efficacy of acute caffeine intake to enhance intense resistance training performance. Fourteen resistance-trained men (age and body mass = 23.1 ± 1.1 years and 83.4 ± 13.2 kg, respectively) who regularly consumed caffeine ingested caffeine (6 mg · kg(-1)) or placebo 1 hour before completion of 4 sets of barbell bench press, leg press, bilateral row, and barbell shoulder press to fatigue at 70-80% 1-repetition maximum. Two minutes of rest was allotted between sets. Saliva samples were obtained to assess caffeine concentration. The number of repetitions completed per set and total weight lifted were recorded as indices of performance. Two-way analysis of variance with repeated measures was used to examine differences in performance across treatment and sets. Compared to placebo, there was a small but significant effect (p < 0.05) of acute caffeine intake on repetitions completed for the leg press but not for upper-body exercise (p > 0.05). Total weight lifted across sets was similar (p > 0.05) with caffeine (22,409.5 ± 3,773.2 kg) vs. placebo (21,185.7 ± 4,655.4 kg), yet there were 9 'responders' to caffeine, represented by a meaningful increase in total weight lifted with caffeine vs. placebo. Any ergogenic effect of caffeine on performance of fatiguing, total-body resistance training appears to be of limited practical significance. Additional research is merited to elucidate interindividual differences in caffeine-mediated improvements in performance.     

Effects of acute exercise intensity on plasma lipids and apolipoproteins in trained runners.

The purpose of this study was to determine the effects of exercise intensity on lipid and lipoprotein metabolism. Concentrations of triglyceride, cholesterol, high-density lipoprotein cholesterol (HDL-C) and its subfractions (HDL2-C and HDL3-C), low-density lipoprotein cholesterol, very-low-density lipoprotein cholesterol, and apolipoproteins A-I, A-II, and B were measured. Ten well-trained runners completed treadmill exercise on two different occasions: a high-intensity session at 75% maximal oxygen consumption lasting 60 min and a low-intensity session at 50% maximal oxygen consumption lasting 90 min. Energy expenditure for each session was equal. Fasted blood samples were obtained 24 h before, immediately before, immediately after, and 1, 24, 48, and 72 h after each exercise session. No significant differences were found for the blood variables across time or between treatments. However, HDL-C and HDL2-C were slightly elevated on the days after each treatment. These results suggest that acute exercise sessions lasting less than 90 min, regardless of intensity, do not elicit plasma lipid, lipoprotein, and apolipoprotein changes in men who are habitually physically active and have high initial concentrations of HDL-C.     

Effect of creatine supplementation on intermittent sprint running performance in highly trained athletes

This study examined the impact of short-term (7-day), high-dose (0.35 g.kg(-1).d(-1)) oral creatine monohydrate supplementation (CrS) on single sprint running performance (40 m, <6 seconds) and on intermittent sprint performance in highly trained sprinters. Nine subjects completed the double-blind cross-over design with 2 supplementation periods (placebo and creatine) and a 7-week wash-out period. A test protocol consisting of 40-m sprint runs was performed, and running velocity was continuously recorded over the total distance. The maximal sprint performance, the relative degree of fatigue at the end of intermittent sprint exercise (6 x 40 m, 30-second rest interval), as well as the degree of recovery (120-second passive rest) remained unchanged following CrS. There were no significant changes related to CrS in absolute running velocity at any distance between start and finish (40 m). It was concluded that no ergogenic effect on single or repeated 40-m sprint times with varying rest periods was observed in highly trained athletes.     

Effects of a concurrent strength and endurance training on running performance and running economy in recreational marathon runners

The purpose of this study was to investigate the effects of a concurrent strength and endurance training program on running performance and running economy of middle-aged runners during their marathon preparation. Twenty-two (8 women and 14 men) recreational runners (mean ± SD: age 40.0 ± 11.7 years; body mass index 22.6 ± 2.1 kg·m?2) were separated into 2 groups (n = 11; combined endurance running and strength training program [ES]: 9 men, 2 women and endurance running [E]: 7 men, and 4 women). Both completed an 8-week intervention period that consisted of either endurance training (E: 276 ± 108 minute running per week) or a combined endurance and strength training program (ES: 240 ± 121-minute running plus 2 strength training sessions per week [120 minutes]). Strength training was focused on trunk (strength endurance program) and leg muscles (high-intensity program). Before and after the intervention, subjects completed an incremental treadmill run and maximal isometric strength tests. The initial values for VO2peak (ES: 52.0 ± 6.1 vs. E: 51.1 ± 7.5 ml·kg?1·min?1) and anaerobic threshold (ES: 3.5 ± 0.4 vs. E: 3.4 ± 0.5 m·s?1) were identical in both groups. A significant time × intervention effect was found for maximal isometric force of knee extension (ES: from 4.6 ± 1.4 to 6.2 ± 1.0 N·kg?1, p < 0.01), whereas no changes in body mass occurred. No significant differences between the groups and no significant interaction (time × intervention) were found for VO2 (absolute and relative to VO2peak) at defined marathon running velocities (2.4 and 2.8 m·s?1) and submaximal blood lactate thresholds (2.0, 3.0, and 4.0 mmol·L?1). Stride length and stride frequency also remained unchanged. The results suggest no benefits of an 8-week concurrent strength training for running economy and coordination of recreational marathon runners despite a clear improvement in leg strength, maybe because of an insufficient sample size or a short intervention period.     

The bioenergetics of optimal performances in middle-distance and long-distance track running.

Aspects of anaerobic and aerobic energy conversion are investigated using a mathematical model of running in conjunction with world-record statistics. Analysis of the data shows that over distances from 1500 to 10,000 m the anaerobic energy utilised is constant and independent of running distance. This result is consistent with the view that the full potential of the anaerobic capacity is available for conversion during extended periods of running; the opinions of Gollnick and Hermansen (1973) and Peronnet and Thibault (1989) that the anaerobic energy contribution declines with race duration are not corroborated. The analysis supports the finding of Peronnet and Thibault (1989) that, for running times below about T = 420 s, the maximum sustainable aerobic power is constant, and that for larger T it then declines progressively. The present analysis shows it falls by some 4.5% over 10,000 m, T approximately 1600 s, indicating that in establishing current world records at 5000 and 10,000 m athletes did not rely solely on glycogen as the source of aerobic metabolism; limited use was made of free fatty acids. For elite male runners, the anaerobic capacity and maximal aerobic power are evaluated as 1570 J/kg and 27.1 W/kg, respectively.     

The effect of graduated compression stockings on running performance

The aim of this study was to examine the effects of wearing different grades of graduated compression stockings (GCS) on 10-km running performance. After an initial familiarization run, 9 male and 3 female competitive runners (VO?max 68.7 ± 5.8 ml·kg?1·min?1) completed 4 10-km time trials on an outdoor 400-m track wearing either control (0 mm Hg; Con), low (12-15 mm Hg; Low), medium (18-21 mm Hg; Med), or high (23-32 mm Hg; Hi) GCS in a randomized counterbalanced order. Leg power was assessed pre and postrun via countermovement jump using a jump mat. Blood-lactate concentration was assessed pre and postrun, whereas heart rate was monitored continuously during exercise. Perceptual scales were used to assess the comfort, tightness, and any pain associated with wearing GCS. There were no significant differences in performance time between trials (p = 0.99). The change in pre to postexercise jump performance was lower in Low and Med than in Con (p < 0.05). Mean heart rate (p = 0.99) and blood lactate (p = 1.00) were not different between trials. Participants rated Con and Low as more comfortable than Med and Hi (p < 0.01), Med and Hi were rated as tighter than Low (p < 0.01), all GCS were rated as tighter than Con (p < 0.01), and Hi was associated with the most pain (p < 0.01). In conclusion, GCS worn by competitive runners during 10-km time trials did not affect performance time; however Low and Med GCS resulted in greater maintenance of leg power after endurance exercise. Athletes rated low-grade GCS as most comfortable garments to wear during exercise.