Mid Sweden University

Introduction

While carbohydrate ingestion can improve endurance performance, relatively little is known about the effect of frequency of carbohydrate ingestion. This may be of particular importance in cross-country skiing, where upper-body propulsion is inevitably decreased during drinking periods. Therefore, the study aim was to examine the effect of ingesting carbohydrate at two different frequencies on 30-km cross-country skiing performance.

Methods

Thirteen participants completed four, 30-km classic roller-skiing time-trials on a simulated treadmill course. A 1:1 maltodextrin-fructose solution was provided at high (6 feeds; HF) and low (2 feeds; LF) frequencies and high (2.4 g∙min^-1, 24%;HC) and low (1.2 g∙min^-1, 12%; LC) rates. Gastrointestinal discomfort was measured using an adapted 6-20 Borg scale.

Results

There were no differences in performance between the four trials (140±16, 139±16, 141±18 and 141±18 min for HF-HC, HF-LC, LF-HC and LF-LC, respectively), although LF-LC was likely harmful compared to HF-LC. However, an order effect was apparent (143±17, 140±16, 140±17 and 138±15 min for trials 1-4, respectively). There was a significant rate x frequency interaction for gastrointestinal discomfort, with greater discomfort in LF-HC (10.3±2.7) compared with HF-HC (8.5±3.1) and HF-LC (8.4±2.7). LF-LC (9.0±2.3) was not significantly different to any other trial.

Discussion

These data suggest there is no significant effect of ingestion frequency on 30-km simulated cross-country ski performance. However, there may be a practically relevant detrimental effect of low frequency ingestion at low rates. Further, LF carbohydrate ingestion increases gastrointestinal discomfort when ingested as HC.