Maximal Cycling Power Research Articles

THE EFFECT OF PRE-EXERCISE CARBOHYDRATE INGESTION ON MAXIMAL NEUROMUSCULAR POWER DURING MODERATE INTENSITY EXERCISE

This study determined if maximal neuromuscular cycling power is reduced during transient hypoglycemia caused by pre-exercise carbohydrate ingestion. Eighteen endurance-trained cyclists with a mean age, mass, height, VO2peak and lactate threshold (LT) of 29.2 ± 1.2 y, 78.8 ± 1.3 kg, 179.2 ± 1.0 cm, 4.4 ± 0.1 lmin−1 and 78.1 ± 1.1% of VO2peak, respectively, participated. Thirty-five minutes prior to exercise at 90% of LT, subjects ingested either 0.5 gkg−1 of glucose (CHO) or a sweet placebo (PLA). Insulin levels were greater and FFA levels lower in CHO vs. PLA (P < 0.05, n = 8). Plasma glucose fell to hypoglycemic levels by 14 min of exercise (3.3 ± 0.2 mM, n = 8) and remained significantly lower (P < 0.05) than PLA for the remainder of the CHO trial (3.1 ± 0.2 vs. 4.5 ± 0.2 mM mean of 14–22 min, CHO vs. PLA, respectively, n = 8). Subjects performed 4 maximal power (P MAX) tests during the 15 - 21 min period, using the inertial load method. Mean PMAX values tended to be lower (P = 0.09) in the CHO vs. PLA (1208 ± 24 vs. 1220 ± 23 W, CHO vs. PLA, respectively) trials and reached significance at sprint #2 (1207 ± 50 vs. 1232 ± 49 W, P < 0.05). In conclusion, transient hypoglycemia caused by pre-exercise carbohydrate ingestion may slightly impair maximal neuromuscular power in trained cyclists at certain time points.

Time Course of Learning to Produce Maximum Cycling Power

The purpose of this investigation was to determine the time course and magnitude of learning effects associated with repeated maximum cycling power tests and to determine if cycle-trained men exhibit different learning effects than active men who are not cycle-trained. Cycle-trained (N = 13) and active men (N = 35) performed short maximal cycling bouts 4 times per day for 4 consecutive days. Inertial load cycle ergometry was used to measure maximum power and pedaling rate at maximum power. Maximum power of the cycle-trained men did not differ across days or bouts. Maximum power of the active men increased 7 % within the first day and 7 % from the mean of day one to day three. Pedaling rate at maximum power did not differ across days or bouts in either the cycle-trained or active men. These results demonstrate that valid and reliable results for maximum cycling power can be obtained from cycle-trained men in a single day, whereas active men require at least 2 days of practice in order to produce valid and reliable values.

Influence of the menstrual cycle phase and menstrual symptoms on maximal anaerobic performance

This study was designed to analyze the effect of the menstrual cycle phase on maximal anaerobic performance during short-term anaerobic tests. Seven eumenorrheic women (NOC) and 10 women using monophasic oral contraceptives (OC) performed three anaerobic tests (force-velocity, multi-jump, and squatting jump tests) during menstruation (M: between days 1 and 4), the midfollicular phase (F: between days 7 and 9), and the midluteal phase (L: between days 19 and 21) of the ovarian cycle. Follicular and luteal phases were confirmed by serum progesterone levels. The order of testing sessions was randomly assigned and a 15-min standardized warm-up preceded each testing session. Rectal temperatures were taken before (Trec(b)) and after (Trec(a)) warm-up. No significant differences were observed among M, F, and L in Trec(b), Trec(a) maximal cycling power (Pmax(c)), maximal jumping power (Pmax(j)), or maximal height of jump (h(j)) in either NOC or OC. Ten of the women suffered premenstrual or menstrual symptoms (MS); the other seven did not report any premenstrual or menstrual discomfort (NMS). Presence or absence of symptoms was not correlated with oral contraceptive use. No significant differences were observed among the three stages of the menstrual cycle in Pmax(c), Pmax(j), or h(j) in NMS. In MS, only Pmax(j) decreased by 8% in M compared with that in F (P < 0.05). Although there were no significant differences in maximal anaerobic performance during different menstrual cycle phases, results of this study suggest that the presence or absence of premenstrual or menstrual syndrome symptoms may have an effect, possibly through an action on the stretch-shortening cycle of tendons and ligaments.

Influence of Menstrual Cycle Phase and Oral Contraceptive Use on the Time-of-Day Effect on Maximal Anaerobic Power

This study was designed to analyse the time-of-day effect in maximal anaerobic power, and the influence of menstrual cycle phase and oral contraceptive use on any diurnal effect. Diurnal variations in maximal cycling power were studied in 11 eumenorrheic women and 10 women using monophasic oral contraceptives. Subjects were tested at 09:00, 14:00 and 18:00 hours, assigned randomly on separate days, in the mid-follicular or pseudo-follicular phase (days 7, 8, 9) and in the mid-luteal or pseudo-luteal phase (days 19, 20, 21) of the menstrual cycle. The order of test sessions was randomly assigned. Body mass was measured before, and rectal temperature after, a standardized 15-min warm-up. Maximal cycling power (Pc) was determined by a force-velocity test. Rectal temperature significantly increased from morning (09:00) to afternoon (14:00 and 18:00) in follicular and luteal phases for eumenorrheic subjects, and in days 7–9 and days 19–21 for contraceptive users (p < 0.05). No significant interaction effects (time of day × group × cycle phase) were observed for rectal temperature. In eumenorrheic subjects, Pc increased significantly from 09:00 to afternoon during the follicular phase (P < 0.05). In contrast, no significant time-of-day effects were observed during the luteal phase in eumenorrheic subjects, and at any cycle phase in contraceptive users. Analysis of variance failed to reveal any significant interaction effects for Pc. This study suggested that the time-of-day effect on maximal anaerobic power could be damped during the luteal phase of eumenorrheic women or at any cycle phase by oral contraceptive use.

Inertial-load method determines maximal cycling power in a single exercise bout.

A cycle ergometer was modified to measure power (P) with resistance provided solely by the moment of inertia (I) of the flywheel. P was calculated as the product of I, angular velocity (omega), and angular acceleration (alpha). Flywheel omega and alpha were determined by means of an optical sensor and a micro-controller based computer interface which measured time (+/- 1 microsecond) and allowed P to be calculated instantaneously (PI) every 3 degrees of pedal crank rotation or averaged over one complete revolution of the pedal cranks (PREV). Values for maximum P were identified from each bout (PI max and PREV max). Mechanical calibration of torque via a resistive strap proved this method to be both valid and accurate. Thirteen active male subjects performed four bouts of maximal acceleration lasting approximately 3-4 s with 2 min resting recovery. The mean coefficient of variation for PREV max was 3.3 +/- 0.6% and the intraclass correlation was 0.99. PREV max averaged 1317 +/- 66 W at 122 +/- 2 rpm, and PI max averaged 2137 +/- 101 W at 131 +/- 2 rpm. PREV max and PI max were highly correlated (r = 0.86 and r = 0.80 respectively, P < 0.002) with estimated lean thigh volume. Therefore, the inertial-load method provides a valid and reliable determination of cycling power in one short exercise bout.