This study evaluated whether national level US cross-country skiers, who did not respond positively to a training program
consisting of high volume and low intensity, would improve if high-intensity
training volume was doubled during a subsequent training year.
Cross-country skiers (N = 14) were evaluated for VO2max, VO2threshold, lactate response, maximum arm power, and competitive results after a year of training. During the following year, Ss were divided into a control group (those who responded well to training in the previous year; N = 7) and a
treatment group (those who responded poorly the previous year; N = 7). The treatment involved training modification to increase high-intensity training time (from <17% to >35%) as part of the total training experience, which was similar in volume for each year.
Significant improved differences for the treatment group for all five variables and none for the control group were observed. Competitively, the treatment group improved to the level of the control group, which also had a marginal, but nonsignificant, performance improvement in the second year.
Implication. Increasing the volume of high-intensity training for athletes who are not responding to high-volume low-intensity training is a likely avenue for performance improvement.