Aerobic capacity and force-velocity characteristics in cross-country skiers at the end of preparatory period and at the beginning of period of competitions

The goal of this study is to compare the dynamics of aerobic and force–velocity characteristics of the shoulder girdle muscles and leg muscles during high-volume aerobic training in junior cross-country skiers in the time interval from the end of the preparatory period to the beginning of the competition period. Eleven junior cross-country skiers were repeatedly tested from December to February. In this period, the volume of aerobic training was 22–23 h per week. During the experimental period, the knee extensors torque in the range of angular velocities of 30–300 degrees/s was observed to decrease, with no changes in the volume of the quadriceps muscle of thigh and knee flexor muscles. The maximal oxygen consumption rate (VO 2 max) was observed to decrease by 6% ( P < 0.05) in the treadmill test, while the oxygen consumption at anaerobic threshold (VO 2 at La = 4 mmol/L) was unchanged. On the contrary, the functional capacity of the shoulder girdle muscles was enhanced. The force-velocity characteristics of the shoulder girdle muscles that were estimated in the maximal anaerobic power test at a double poling ergometer increased by 16% ( P < 0.01), and the volume of the triceps muscle of arm increased by 4.6 ( P < 0.01). The aerobic capacity of the shoulder girdle muscles that were estimated by the VO 2 at La = 4 mmol/L increased by 30% ( P < 0.05). The potential for increasing the performance of junior cross-country skiers seems to be associated with the increased functional capacity of the shoulder girdle muscles.