Kevin G Thompson

It has been proposed that an even-pacing strategy is optimal for events lasting <120 s, but this assertion is not well-established. This study tested the hypothesis that even-paced cycling is less challenging than self- or variable-paced cycling. Ten well-trained male cyclists (VO2max, 4.89 ± 0.32 L min(-1)) completed a self-paced (SP) 20-km time trial followed by time- and work-matched even-paced (EP 100% SP mean power) and variable-paced (VP 142 and 72% SP mean power, 1:1.5 high:low power ratio) trials in a random, counterbalanced order. During all trials expired air and heart rate were analysed throughout, blood lactate was sampled every 4 km, and perceptual responses (rating of perceived exertion (RPE) and affect) were assessed every 2 km and post-trial. There were no whole trial statistically significant differences between trials for any of the respiratory variables measured, although there was a trend for higher RER's in VP compared to EP (P = 0.053). Blood lactate was lower in EP compared to VP (P = 0.001) and SP (P = 0.001), and higher in SP compared to VP (P = 0.008). RPE was lower, and affect more positive, in EP compared to both SP and VP (P > 0.05). The results of this study show that, for a time- and work-matched 20-km time trial, an even-paced strategy results in attenuated perturbations in the physiological response and lower perception of effort in comparison to self- and variable-paced strategies.

Exercise is known to result in hemodynamic changes in the bi-lateral prefrontal cortex. The aim of this study was to investigate hemodynamic changes in right and left hemispheres of the prefrontal cortex (PFC) during incremental cycling exercise. Following ten minutes rest, nine participants (mean age 26.6 ± 2.5 years, mass 77.5 ± 9.7 kg and stature 1.79 ± 0.9 m) cycled at between 100 and 150 W for four minutes. Thereafter, resistance was increased by 25 W every four minutes until exhaustion. Respiratory exchange and concentrations of oxy- ([HbO2]), deoxy- ([(HHb]) and total haemoglobin ([Hbtot]) in the PFC were continuously measured. Data were averaged for 60-s at rest and preceding VT1, VT2 and volitional exhaustion (EXH) and after five minutes recovery (REC). Subjective ratings of affect were measured at VT1, VT2 and VT1 minus 25W (VT1-25W) and VT2 plus 25W (VT2+25W). There were no between hemisphere differences in [HbO2] or [Hbtot] at rest, VT1 or REC; or in [HHb] at any point. ...

The aim of the study was to assess the reproducibility of pacing strategy, physiological and perceptual responses during simulated 20-km cycling time trials. Seventeen well-trained male cyclists ([Formula: see text] = 4.70 ± 0.33 L min(-1)) completed three 20-km time trials on a Velotron Pro cycle ergometer within a maximum duration of 14 days. During all trials power output, cadence and respiratory exchange were recorded throughout, rating of perceived exertion and affective response were recorded every 2-km and capillary blood was sampled and assayed for the determination of lactate concentration every 4-km. Power output data was assigned to 1-km 'bins' and expressed relative to the mean to quantify pacing strategy. Reproducibility of the pacing strategy and the whole trial mean responses was subsequently quantified using typical error (TE) with 90% confidence intervals. The pacing strategy adopted was similar across repeat trials, though there was a higher degree of variability at the start and end of the trial (TE = 6.6 and 6.8% for the first and last 1-km), and a trend for a progressively blunted start on repeat trials. The reproducibility of performance, cardiorespiratory and perceptual measures was good (TE range 1.0-4.0%), but blood lactate exhibited higher variability (TE = 17.7%). The results demonstrate the performance, perceptual and physiological response to self-paced 20-km time trials is reproducible in well-trained cyclists. Future research should acknowledge that variability in pacing strategy at the start and end of a self-paced bout is likely regardless of any intervention employed.

The collection of retrospective lap times from video footage is a potentially useful research tool to analyze the pacing strategies in any number of competitive events. The aim of this study was to validate a novel method of obtaining running split-time data from publically available video footage. Videos of the 1500-m men's final from the 2004 and 2008 Olympics, 2005 and 2009 World Championships, and 2010 European Championships were obtained from the YouTube Web site, and split times were collected from all competitors using frame-by-frame playback. The typical error of video split times ranged between 0.02 s and 0.11 s for the 4 laps when compared with official split times. Video finishing times were also similar to official finishing times (typical error of 0.04 s). The method was shown to be highly reliable with a typical error of 0.02 s when the same video was analyzed on 2 occasions separated by 8 mo. Video data of track races are widely available; however, camera angles a...

Nitrate supplementation improves endurance exercise and single bouts of high-intensity activity, but its effect on repeated sprints is unclear. This study is the first to investigate the effects of acute dietary nitrate supplementation during a high-intensity intermittent-sprint test to exhaustion. Team-sport athletes (9 male, age 22.3 ± 2.1 y, VO2max 57.4 ± 8.5 mL · kg-1 · min-1; 7 female, age 20.7 ± 1.3 y, VO2max 47.2 ± 8.5 mL · kg-1 · min-1) were assigned to a double-blind, randomized, crossover design. Participants consumed 70 mL of concentrated beetroot juice containing a minimum of 0.3 g of nitrate (NT) or 70 mL of placebo (PL) 2 h before a repeated-sprint protocol involving repeated 8-s sprints with 30-s recovery on a cycle ergometer to exhaustion. Fewer sprints (NT = 13 ± 5 vs PL = 15 ± 6, P = .005, d = 0.41) and less total work (NT = 49.2 ± 24.2 kJ vs PL = 57.8 ± 34.0 kJ, P = .027, d = 0.3) were completed in NT relative to PL. However there was no difference in overall mean...

To quantify the effects of a 12-wk isolated core-training program on 50-m front-crawl swim time and measures of core musculature functionally relevant to swimming. Twenty national-level junior swimmers (10 male and 10 female, 16 ± 1 y, 171 ± 5 cm, 63 ± 4 kg) participated in the study. Group allocation (intervention [n = 10], control [n = 10]) was based on 2 preexisting swim-training groups who were part of the same swimming club but trained in different groups. The intervention group completed the core training, incorporating exercises targeting the lumbopelvic complex and upper region extending to the scapula, 3 times/wk for 12 wk. While the training was performed in addition to the normal pool-based swimming program, the control group maintained their usual pool-based swimming program. The authors made probabilistic magnitude-based inferences about the effect of the core training on 50-m swim time and functionally relevant measures of core function. Compared with the control group, the core-training intervention group had a possibly large beneficial effect on 50-m swim time (-2.0%; 90% confidence interval -3.8 to -0.2%). Moreover, it showed small to moderate improvements on a timed prone-bridge test (9.0%; 2.1-16.4%) and asymmetric straight-arm pull-down test (23.1%; 13.7-33.4%), and there were moderate to large increases in peak EMG activity of core musculature during isolated tests of maximal voluntary contraction. This is the first study to demonstrate a clear beneficial effect of isolated core training on 50-m front-crawl swim performance.

We tested the hypothesis that priming exercise would speed V(O2) kinetics during treadmill running. Eight subjects completed a square-wave protocol, involving two bouts of treadmill running at 70% of the difference between the running speeds at lactate threshold (LT) and V(O2) max, separated by 6-min of walking at 4 km h(-1), on two occasions. Oxygen uptake was measured breath-by-breath and subsequently modelled using non-linear regression techniques. Heart rate and blood lactate concentration were significantly elevated prior to the second exercise bout compared to the first. However, V(O2) kinetics was not significantly different between the first and second exercise bouts (mean+/-S.D., phase II time constant, Bout 1: 16+/-3s vs. Bout 2: 16+/-4s; V(O2) slow component amplitude, Bout 1: 0.24+/-0.10 L min(-1)vs. Bout 2: 0.20+/-0.12 L min(-1); mean response time, Bout 1: 34+/-4s vs. Bout 2: 34+/-6s; P>0.05 for all comparisons). These results indicate that, contrary to previous findings with other exercise modalities, priming exercise does not alter V(O2) kinetics during high-intensity treadmill running, at least in physically active young subjects. We speculate that the relatively fast V(O2) kinetics and the relatively small V(O2) slow component in the control ('un-primed') condition negated any enhancement of V(O2) kinetics by priming exercise in this exercise modality.

ABSTRACT This study evaluated the impact of a high-intensity strength training session on rowing sprint performance. Ten male club rowers performed a baseline counter-movement jump (CMJ) and a 250 m rowing ergometer sprint (250 m). Twenty-four hours after baseline, participants performed a high-intensity strength training session (ST) consisting of multi-joint barbell exercises. At 24 h, 48 h and 72 h post-ST, CMJ and 250 m were repeated alongside assessment of plasma creatine kinase (CK) and perceived muscle soreness. At 24 h post-ST 250 m performance decreased significantly (90% CI: 0.3 - 0.7 s), but returned to pre-test values at 48 h. There was a significant decrease in CMJ height at 48 h post ST (90% CI: -0.7 - -4.1 cm). Perceived muscle soreness was significantly greater than baseline at all assessed time points following ST (p < 0.05). There was a significant increase in CK from baseline to 24 h (90% CI: 146 - 390 U/L). High-intensity strength training was observed to adversely affect 250 m rowing ergometer performance after 24 h and coincided with transient muscle damage.

Effective regulation of pace enables the majority of runners to complete competitive endurance events without mishap. However, some runners do experience exercise-induced collapse associated with postural hypotension, which in rare cases results from life-threatening conditions such as cardiac disorders, cerebral events, heat stroke and hyponatraemia. Despite the experience of either catastrophic system failure or extreme peripheral muscle fatigue, some runners persist in attempting to reach the finish line, and this often results in a sequence of dynamic changes in posture and gait that we have termed the 'Foster collapse positions'. The initial stage involves an unstable gait and the runner assumes the 'Early Foster' collapse position with hips slightly flexed and their head lowered. This unstable gait further degrades into a shuffle referred to as the 'Half Foster' collapse position characterized by hip flexion of approximately 90° with the trunk and head parallel to the ground. At this point, the muscles of postural support and the co-ordination of propulsion begin to be compromised. If the condition worsens, the runner will fall to the ground and assume the 'Full Foster' collapse position, which involves crawling forwards on knees and elbows towards the finish line, with their trunk angled such that the head is at a lower angle than the hips. Upon reaching the finish line, or sometimes before that, the runner may collapse and remain prone until recovering either with or without assistance or medical treatment. The Foster collapse positions are indicative of a final, likely primordial, protective mechanism designed to attenuate postural hypotension, cardiac 'pump' insufficiency or cerebral blood flow deficiency. Continuing to attempt to reach the finish line in this impaired state is also perhaps indicative of a high psychological drive or a variety of neurological and psychological pathologies such as diminished sensitivity to interoceptive feedback, unrealistic situational appraisal or extreme motivational drives. A better understanding of the physiological, neurological and psychological antecedents of the Foster collapse sequence remains an important issue with practical implications for runner safety and theoretical understanding of collapses during exercise.

This study examined the effect of low- and high-intensity running on cognitive thoughts (an individual's "inner dialogue") and its relationship to ratings of perceived exertion (RPE). Cognitive thoughts and RPE of eight runners were collected during a 40-min. treadmill run at either a low (50% peak running speed) or a high (70% peak running speed) exercise intensity. Runners were asked to place their thoughts into one of 10 themed categories, which incorporated a broad association/dissociation classification (Schomer, 1986, 1987). At a low intensity and RPE (6-10), runners reported more dissociative thoughts, while at a high intensity and RPE (16-20) they reported more associative thoughts. Further, although the runners may report a particular RPE, the inner dialogue and description of perceived exertion and fatigue may be markedly different. These findings suggest that an athlete's "internal dialogue" is intensity dependent, and may relate to the more urgent need to self-monitor physical changes and sensations during high-intensity running.

Iron deficiency is prevalent in distance runners and may impair endurance performance. The current practice of oral supplementation is slow and often not well tolerated. The aim of this study was to assess the efficacy of intravenous (IV) iron supplementation (ferric carboxymaltose) compared with oral supplementation (ferrous sulfate) on iron status, hemoglobin mass (Hbmass), and physiological indices of running performance in distance runners. Twenty-seven highly trained distance runners with low (LOW) (ferritin <35 μg·L(-1) and transferrin saturation <20%, or ferritin <15 μg·L(-1)) or suboptimal (SUB) iron status (ferritin <65 μg·L(-1)) were supplemented with either IV iron (Ferinject®) or oral (ORAL) supplements (Ferrogradumet) for 6 wk. Iron status and Hbmass were assessed before supplementation and at 1, 2, 4, 6, and 8 wk in the four groups (IV LOW, IV SUB, ORAL LOW, and ORAL SUB). In addition, athletes completed a treadmill running test for running economy, lactate threshold, and V˙O2max before and after supplementation. Both forms of supplementation substantially increased ferritin levels in all four groups. IV supplementation resulted in higher ferritin in both IV groups compared with both ORAL groups from week 1 onward. Hemoglobin concentration did not change substantially in any group. Hbmass increased in IV LOW (mean = +4.9%, 90% confidence interval [CI] = 1.1%-8.9%) and was accompanied by an increase in V˙O2max (mean = +3.3%, 90% CI = 0.4%-6.3%) and run time to exhaustion (mean = +9.3%, 90% CI = 0.9%-18.3%. IV supplementation can effectively increase iron stores in iron-deficient runners within 6 wk and, if Hbmass is compromised, may enhance endurance capacity by facilitating erythropoiesis. Hbmass appears a more sensitive tool for measuring changes in whole body hemoglobin than hemoglobin concentration and may be useful in the diagnosis and follow-up for iron deficiency.