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  • Author: Alan St. Clair Gibson x
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Deryn Bath, Louise A. Turner, Andrew N. Bosch, Ross Tucker, Estelle V. Lambert, Kevin G. Thompson and Alan St. Clair Gibson

Purpose:

The aim of this study was to examine performance, pacing strategy and perception of effort during a 5 km time trial while running with or without the presence of another athlete.

Methods:

Eleven nonelite male athletes participated in five 5 km time trials: two self-paced, maximal effort trials performed at the start and end of the study, and three trials performed in the presence of a second runner. In the three trials, the second runner ran either in front of the subject, behind the subject, or next to the subject. Performance times, heart rate, RPE, and a subjective assessment of the effect of the second runner on the athlete’s performance were recorded during each of the trials.

Results:

There was no significant difference in performance times, heart rate or RPE between any of the five trials. Running speed declined from the 1st to the 4th kilometer and then increased for the last kilometer in all five trials. Following the completion of all trials, 9 of the 11 subjects perceived it to be easier to complete the 5 km time trial with another runner in comparison with running alone.

Conclusions:

While the athletes perceived their performance to be improved by the presence of another runner, their pacing strategy, running speed, heart rate and RPE were not significantly altered. These findings indicate that an athlete’s subconscious pacing strategy is robust and is not altered by the presence of another runner.

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Amanda Claassen, Estelle V. Lambert, Andrew N. Bosch, Ian M. Rodger, Alan St. Clair Gibson and Timothy D. Noakes

The impact of altered blood glucose concentrations on exercise metabolism and performance after a low carbohydrate (CHO) diet was investigated. In random order, 1 wk apart, 9 trained men underwent euglycemic (CI) or placebo (PI) clamps, while performing up to 150 min of cycling at 70% VO2max, after 48 h on a low CHO diet. The range in improvement in endurance capacity with glucose infusion was large (28 ± 26%, P < 0.05). Fifty-six percent of subjects in CI failed to complete 150 min of exercise despite maintenance of euglycemia, while only 2 subjects in PI completed 150 min of exercise, despite being hypoglycemic. Total CHO oxidation remained similar between trials. Despite longer exercise times in CI, similar amounts of muscle glycogen were used to PI. Maintenance of euglycemia in the CHO-depleted state might have an ergogenic effect, however, the effect is highly variable between individuals and independent of changes in CHO oxidation.

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Thomas W. Jones, Ian H. Walshe, David L. Hamilton, Glyn Howatson, Mark Russell, Oliver J. Price, Alan St Clair Gibson and Duncan N. French

Purpose:

To compare anabolic signaling responses to differing sequences of concurrent strength and endurance training in a fed state.

Methods:

Eighteen resistance-trained men were randomly assigned to the following experimental conditions: strength training (ST), strength followed by endurance training (ST-END), or endurance followed by strength training (END-ST). Muscle tissue samples were taken from the vastus lateralis before each exercise protocol, on cessation of exercise, and 1 h after cessation of strength training. Tissue was analyzed for total and phosphorylated (p-) signaling proteins linked to the mTOR and AMPK networks.

Results:

Strength-training performance was similar between ST, ST-END, and END-ST. p-S6k1 was elevated from baseline 1 h posttraining in ST and ST-END (both P < .05). p-4E-BP1 was significantly lower than baseline post-ST (P = .01), whereas at 1 h postexercise in the ST-END condition p-4E-BP1 was significantly greater than postexercise (P = .04). p-ACC was elevated from baseline both postexercise and 1 h postexercise (both P < .05) in the END-ST condition. AMPK, mTOR, p38, PKB, and eEF2 responded similarly to ST, ST-END, and END-ST. Signaling responses to ST, ST-END, and END were largely similar. As such it cannot be ascertained which sequence of concurrent strength and endurance training is most favorable in promoting anabolic signaling.

Conclusions:

In the case of the current study an acute bout of concurrent training of differing sequences elicited similar responses of the AMPK and mTOR networks.