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. 2022 Aug 1;14(1):149.
doi: 10.1186/s13102-022-00543-w.

Prolonged cycling lowers subsequent running mechanical efficiency in collegiate triathletes

J A Stewart  1   2 , E K Merritt  3 , D E Lidstone  2 , J M McBride  2   4 , K A Zwetsloot  5   6
Affiliations

Prolonged cycling lowers subsequent running mechanical efficiency in collegiate triathletes

J A Stewart et al. BMC Sports Sci Med Rehabil. .

Abstract

Background: A significant challenge that non-elite collegiate triathletes encounter during competition is the decline in running performance immediately after cycling. Therefore, the purpose of this study was to determine if performing a 40-km bout of cycling immediately before running would negatively influence running economy and mechanical efficiency of running during simulated race conditions in collegiate triathletes.

Methods: Eight competitive club-level collegiate triathletes randomly performed two trials: cycling for 40 km (Cycle-Run) or running for 5 km (Run-Run), immediately followed by a four-minute running economy and mechanical efficiency of running test at race pace on an instrumented treadmill. Blood lactate, respiratory exchange ratio, mechanical work, energy expenditure, and muscle glycogen were also measured during the four-minute running test.

Results: Mechanical efficiency of running, but not running economy, was significantly lower in Cycle-Run, compared to Run-Run (42.1 ± 2.5% vs. 48.1 ± 2.5%, respectively; p = 0.027). Anaerobic energy expenditure was significantly higher in the Cycle-Run trial, compared to the Run-Run trial (16.3 ± 2.4 vs. 7.6 ± 1.1 kJ; p = 0.004); while net (151.0 ± 12.3 vs. 136.6 ± 9.6 kJ; p = 0.204) and aerobic energy expenditure (134.7 ± 12.3 vs. 129.1 ± 10.5 kJ; p = 0.549) were not statistically different between trials. Analysis of blood lactate, respiratory exchange ratio, mechanical work, and changes in muscle glycogen revealed no statistically significant differences between trials.

Conclusions: These results suggest that mechanical efficiency of running, but not running economy, is decreased and anaerobic energy expenditure is increased when a 40-km bout of cycling is performed immediately before running in collegiate triathletes.

Keywords: Energy expenditure; Lactate; Muscle glycogen; Running economy; Work.

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Conflict of interest statement

The authors declare that they have no competing interests.

Figures

Fig. 1
Fig. 1
Mechanical efficiency of running (MER) during the four-minute data collection run of the Cycle-Run and Run–Run trials. Data are expressed as mean ± SEM. * indicates significant difference between trials at p = 0.027
Fig. 2
Fig. 2
Energy expenditure during the four-minute data collection run of the Cycle-Run and Run–Run trials. Aerobic = aerobic energy expenditure; Anaerobic = anaerobic energy expenditure. Data are expressed as mean ± SEM. * indicates significant difference in anaerobic energy expenditure between trials at p = 0.004
Fig. 3
Fig. 3
Change from rest in blood lactate concentrations immediately after the four-minute data collection run of the Cycle-Run and Run–Run trials. Pre = resting; Post = immediately after run. Data are expressed as mean ± SEM
See this image and copyright information in PMC

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