Reliability Of Power Output Research Articles

Reliability of power output, maximal rate of capillary blood lactate accumulation, and phosphagen contribution time following 15-s sprint cycling in amateur cyclists.

Based on Mader's mathematical model, the rate of capillary blood lactate concentration (νLamax) following intense exercise is thought to reflect the maximal glycolytic rate. We aimed to investigate the reliability of important variables of Mader's model (i.e. power output, lactate accumulation, predominant phosphagen contribution time frames (tP Cr)) and resulting νLamax values derived during and after a 15-s cycling sprint. Fifty cyclists performed a 15-s all-out sprint test on a Cyclus2 ergometer three times. The first sprint test was considered a familiarization trial. Capillary blood was sampled before and every minute (for 8 min) after the sprint to determine νLamax. Test-retest analysis between T2 and T3 revealed excellent reliability for power output (Pmean and Ppeak; ICC = 0.99, 0.99), ∆La and νLamax with tPCr of 3.5 s (ICC = 0.91, 0.91). νLamax calculated with tPCr = tP peak (ICC = 0.87) and tP Cr = tPpeak-3.5% (ICC = 0.79) revealed good reliability. tPpeak and tPpeak-3.5% revealed only poor and moderate reliability (ICC = 0.41, 0.52). Power output and ∆La are reliable parameters in the context of this test. Depending on tPCr, reliability of νLamax varies considerably with tP Cr of 3.5 s showing excellent reliability. We recommend standardization of this type of testing especially tP Cr.

Power output reliability between Garmin® Vector meter and Lode Excalibur Sport® cycle ergometer

Power output can be used to control training load. However, it is important to know if different power meters are reliable, because variations in their measures have direct repercussions on the training program. The aim of this study was to verify the reliability of the power output during two different pedaling protocols (incremental and variable tests) obtained with GARMIN Vector pedals and to compare it with the gold standard LODE Excalibur cycle ergometer. Fourteen male cyclists (30 (6) years of age, maximal power 423 (23) W) performed a maximal test (initial load 100 W with 25 W/min increments) and a variable load test (100–400 W) with the LODE Excalibur cycle ergometer instrumented with GARMIN Vector pedals (coupled on the LODE Excalibur cranks). Student’s t test, intraclass correlation coefficient (ICC), and Bland-Altman analysis were used to evaluate meters’ differences and reliability, respectively. All measures performed in the incremental test (100–400 W) and two measures (100 W, 150 W) of the variable load test showed no power output measurements’ reliability between the GARMIN Vector pedals and the LODE Excalibur cycle ergometer (p < 0.05). The high non-systematic errors in power output measured by the GARMIN Vector pedals (low repeatability) can generate problems when using this equipment for the training periodization in cycling.

Reliability of Power Output during Dynamic Cycling

The aims of the present study were to determine the influence of familiarization on the reliability of power output during a dynamic 30-km cycling trial and to determine the test-retest reliability following a 6-week period. Nine trained male cyclists performed five self-paced 30-km cycling trials, which contained three 250-m sprints and three 1-km sprints. The first three of these trials were performed in consecutive weeks (Week 1, Week 2 and Week 3), while the latter two trials were consecutively conducted 6 wk following (Week 9 and Week 10). Subjects were instructed to complete each sprint, as well as the entire trial in the least time possible. Reproducibility in average power output over the entire 30-km trial for Week 2 and 3 alone (coefficient of variation, CV = 2.4 %, intra-class correlation coefficient, ICC = 0.93) was better than for Week 1 and 2 (CV = 5.5 %, ICC = 0.77) and Week 9 and 10 alone (CV = 5.3 %, ICC = 0.57). These results indicate that high reliability during a dynamic 30-km cycling trial may be obtained after a single familiarization trial when subsequent trials are performed within 7 days. However, if cyclists do not perform trials for six weeks, the same level of reliability is not maintained.

Reliability of power output during intermittent high-intensity cycling.

We determined the number of trials on consecutive days required to establish high reliability of an intermittent high-intensity cycling test in subjects unfamiliar with multiple-sprint exercise. We also examined the extent to which this reliability could be maintained for 6 d. Five untrained men performed a multiple-sprint test (10 x 7 s, with each sprint separated by 30 s) on each of four consecutive days (days 1-4), then rested for 6 d, and finally performed two additional tests on consecutive days (days 11 and 12). For statistical comparisons (analyses of variance), mean power outputs during sprints 8, 9, and 10 (MP8-10) on each test day were calculated for each of the 4th, 5th, and 6th seconds of the sprints, i.e., MP8-10(4th), MP8-10(5th), and MP8-10(6th). Peak power during each sprint was also examined. For days 3 and 4, values for MP8-10(4th), MP8-10(5th), and MP8-10(6th) were greater than on day 1 (P < 0.05). MP8-10(6th) on day 2 was also greater than on day 1 (P < 0.05). There were no differences in MP8-10 among days 2, 3, 4, 11, and 12. Also, peak power on day 1 was lower (P < 0.05) than peak power for all other days, which were not different from one another. The coefficients of variation (CV) for MP8-10 on day 3 versus day 4 were 3.3%, 2.5%, and 2.9% for MP8-10(4th), MP8-10(5th), and MP8-10(6th), respectively. The CV for MP8-10(4th), MP8-10(5th), and MP8-10(6th) on days 4, 11, and 12 ranged from 2.1 to 3.9%, with an overall mean of 3.1%. The greatest CV for MP8-10 was 5.2% for MP8-10(6th) on days 2 versus 3 and 2 versus 4. The mean CV for peak power for all pairwise combinations of days 4, 11, and 12 was 2.8%. In conclusion, satisfactory reliability of intermittent cycling tests is achieved after two familiarization sessions identical to the tests, and that reliability can be maintained for 6 d.

Implementation of a two-dimensional biomechanical model i n an opto-electronic motion analysis system

The objective of this study was to implement a dynamic, two-dimensional biomechanical model, a force plate, and electromyography in a three-dimensional, opto-electronic motion analysis system. Further objectives were to present kinematic and kinetic data for basic movements used in rehabilitation and athletic testing, and to make the system rapid and adaptable for clinical use. Kinematic data, including joint movements and muscle length changes, as well as kinetic data, including net torque and net power output, are presented for the ankle, knee and hip joints when performing two-legged vertical counter-movement jumps, walking, and one-leg long hops. Coefficients of variation for net torque and the net power output were between 1.6% and 18·1% when analysing the countermovement jumps, and there were similar results for walking. When performing the hop, the coefficients of variation for net torques were all less than 16%, but power output values were unequivocally non-satisfactory (30% maximum). In conclusion, reliability was acceptable for the counter-movement jumps and for the analysis of walking, but power output reliability for the hops at touch-down was found to be poor, probably due to soft tissue and marker movement relative to the underlying bone. The moderate amount of time needed for testing makes the system useful for clinical practice.