. Among methods to carry fluids, handheld bottles or bottles carried in belt holders on the waist are common. Considerable efforts have been made to identify the optimal hydration protocols during ultralong running events. 4 – 7 However, there is a paucity of evidence on the impact of carrying water or
Heather K. Vincent, Laura A. Zdziarski, Kyle Fallgatter, Giorgio Negron, Cong Chen, Trevor Leavitt, MaryBeth Horodyski, Joseph G. Wasser and Kevin R. Vincent
Peter J. Whalley, Chey G. Dearing and Carl D. Paton
effects. 14 To our knowledge, there is currently no published research comparing the effects of different caffeine delivery forms on exercise performance. Therefore, the primary aim of this study was to investigate the ergogenic effects of different forms of caffeine supplementation on 5-km running
Diogo V. Leal, Lee Taylor and John Hough
cyclists, its application within other athletes (eg, runners) is evidently lacking. Given a 30-minute running protocol at 80% of maximal oxygen uptake ( V ˙ O 2 max ) has been reported to elevate plasma cortisol by ∼20%, 10 and a running test to exhaustion at 100% ventilatory threshold increased plasma
John Molphy, John W. Dickinson, Neil J. Chester, Mike Loosemore and Gregory Whyte
ergogenic action of 2- and 4-mg inhaled terbutaline on exercise performance during a 3-km running time trial and to measure urinary thresholds of terbutaline postexercise performance. Methods Following ethical approval from the Liverpool John Moores University Research Ethics Committee (Ethics No. P11SPS044
Guillaume P. Ducrocq, Thomas J. Hureau, Olivier Meste and Grégory M. Blain
Exercise performance of many sport disciplines (eg, team sports, racquet sports, short and mid-distance running) requires both high endurance and muscle power output capabilities. 1 , 2 Usually, these specific physical capabilities are developed separately, but the increasing number of
Hugh Trenchard, Andrew Renfree and Derek M. Peters
Drafting in cycling influences collective behavior of pelotons. Although evidence for collective behavior in competitive running events exists, it is not clear if this results from energetic savings conferred by drafting. This study modeled the effects of drafting on behavior in elite 10,000-m runners.
Using performance data from a men’s elite 10,000-m track running event, computer simulations were constructed using Netlogo 5.1 to test the effects of 3 different drafting quantities on collective behavior: no drafting, drafting to 3 m behind with up to ~8% energy savings (a realistic running draft), and drafting up to 3 m behind with up to 38% energy savings (a realistic cycling draft). Three measures of collective behavior were analyzed in each condition: mean speed, mean group stretch (distance between first- and last-placed runner), and runner-convergence ratio (RCR), which represents the degree of drafting benefit obtained by the follower in a pair of coupled runners.
Mean speeds were 6.32 ± 0.28, 5.57 ± 0.18, and 5.51 ± 0.13 m/s in the cycling-draft, runner-draft, and no-draft conditions, respectively (all P < .001). RCR was lower in the cycling-draft condition but did not differ between the other 2. Mean stretch did not differ between conditions.
Collective behaviors observed in running events cannot be fully explained through energetic savings conferred by realistic drafting benefits. They may therefore result from other, possibly psychological, processes. The benefits or otherwise of engaging in such behavior are as yet unclear.
Dietmar Wallner, Helmut Simi, Gerhard Tschakert and Peter Hofmann
To analyze the acute physiological response to aerobic short-interval training (AESIT) at various high-intensity running speeds. A minor anaerobic glycolytic energy supply was aimed to mimic the characteristics of slow continuous runs.
Eight trained male runners (maximal oxygen uptake [VO2max] 55.5 ± 3.3 mL · kg−1 · min−1) performed an incremental treadmill exercise test (increments: 0.75 km · h−1 · min−1). Two lactate turn points (LTP1, LTP2) were determined. Subsequently, 3 randomly assigned AESIT sessions with high-intensity running-speed intervals were performed at speeds close to the speed (v) at VO2max (vVO2max) to create mean intensities of 50%, 55%, and 60% of vLTP1. AESIT sessions lasted 30 min and consisted of 10-s work phases, alternated by 20-s passive recovery phases.
To produce mean velocities of 50%, 55%, and 60% of vLTP1, running speeds were calculated as 18.6 ± 0.7 km/h (93.4% vVO2max), 20.2 ± 0.6 km/h (101.9% vVO2max), and 22.3 ± 0.7 km/h (111.0% vVO2max), which gave a mean blood lactate concentration (La) of 1.09 ± 0.31 mmol/L, 1.57 ± 0.52 mmol/L, and 2.09 ± 0.99 mmol/L, respectively. La at 50% of vLTP1 was not significantly different from La at vLTP1 (P = .8894). Mean VO2 was found at 54.0%, 58.5%, and 64.0% of VO2max, while at the end of the sessions VO2 rose to 71.1%, 80.4%, and 85.6% of VO2max, respectively.
The results showed that AESIT with 10-s work phases alternating with 20 s of passive rest and a running speed close to vVO2max gave a systemic aerobic metabolic profile similar to slow continuous runs.
Marc Sim, Brian Dawson, Grant Landers, Dorine W. Swinkels, Harold Tjalsma, Debbie Trinder and Peter Peeling
The effect of exercise modality and intensity on Interleukin-6 (IL-6), iron status, and hepcidin levels was investigated. Ten trained male triathletes performed 4 exercise trials including low-intensity continuous running (L-R), low-intensity continuous cycling (L-C), high-intensity interval running (H-R), and high-intensity interval cycling (H-C). Both L-R and L-C consisted of 40 min continuous exercise performed at 65% of peak running velocity (vVO2peak) and cycling power output (pVO2peak), while H-R and H-C consisted of 8 × 3-min intervals performed at 85% vVO2peak and pVO2peak. Venous blood samples were drawn pre-, post-, and 3 hr postexercise. Significant increases in postexercise IL-6 were seen within each trial (p < .05) and were significantly greater in H-R than L-R (p < .05). Hepcidin levels were significantly elevated at 3 hr postexercise within each trial (p < .05). Serum iron levels were significantly elevated (p < .05) immediately postexercise in all trials except L-C. These results suggest that, regardless of exercise mode or intensity, postexercise increases in IL-6 may be expected, likely influencing a subsequent elevation in hepcidin. Regardless, the lack of change in postexercise serum iron levels in L-C may indicate that reduced hemolysis occurs during weight-supported, low-intensity activity.
Konstantinos Tsintzas, Raymond Liu, Clyde Williams, Ian Campbell and George Gaitanos
Seven experienced endurance runners completed a 30-km road race on two occasions separated by 10 days. On each occasion the subjects consumed 250 ml of either a 5% carbohydrate (CHO) solution or nonflavored tap water (W) immediately prior to the start of the race, and 150 ml of the assigned fluid every 5 km thereafter. Performance time for the CHO trial was faster compared with the time recorded for the W trial (128.3 ± 19.9 min vs. 131.2 ± 18.7 min [p<0.01] respectively). Running speed was maintained throughout the race in the CHO trial, whereas a decrease in the running speed occurred after 25 km (p<0.05) in the W trial. No difference was found between the two trials in blood glucose concentration, plasma electrolyte concentrations, body weight loss, change in plasma volume, and rating of perceived exertion. Blood lactate concentration was higher at 25 km during the CHO trial compared with the W trial (p<0.01), but plasma FFA and glycerol concentrations were lower at 30 km during the CHO trial than during the W trial (p<0.05). In conclusion, this study shows that performance time for a 30-km road race is improved after ingesting a 5% CHO solution.
Joanne L. Fallowfield, Clyde Williams and Rabindar Singh
Recovery from prolonged exercise involves both rehydration and replenishment of endogenous carbohydrate stores. The present study examined the influence of ingesting a carbohydrate-electrolyte (CE) solution following prolonged running, on exercise capacity 4 hr later. Twelve men and 4 women were divided into two matched groups, which were randomly assigned to either a control (P) or a carbohydrate (CHO) condition. Both groups ran at 70% of maximal oxygen uptake (