Critical aerobic power during simulated 20 km bicycle racing

Comparison of inter-trial recovery times for the determination of critical power and W' in cycling

Critical Power (CP) and W' are often determined using multi-day testing protocols. To investigate this cumbersome testing method, the purpose of this study was to compare the differences between the conventional use of a 24-h inter-trial recovery time with those of 3 h and 30 min for the determination of CP and W'.

METHODS

9 moderately trained cyclists performed an incremental test to exhaustion to establish the power output associated with the maximum oxygen uptake (p[Formula: see text]_max), and 3 protocols requiring time-to-exhaustion trials at a constant work-rate performed at 80%, 100% and 105% of p[Formula: see text]_max. Design: Protocol A utilised 24-h inter-trial recovery (CP₂₄/W'₂₄), protocol B utilised 3-h inter-trial recovery (CP₃/W'₃), and protocol C used 30-min inter-trial recovery period (CP_0.5/W'_0.5). CP and W' were calculated using the inverse time (1/t) versus power (P) relation (P = W'(1/t) + CP).

RESULTS

95% Limits of Agreement between protocol A and B were -9 to 15 W; -7.4 to 7.8 kJ (CP/W') and between protocol A and protocol C they were -27 to 22 W; -7.2 to 15.1 kJ (CP/W'). Compared to criterion protocol A, the average prediction error of protocol B was 2.5% (CP) and 25.6% (W'), whilst for protocol C it was 3.7% (CP) and 32.9% (W').

CONCLUSION

3-h and 30-min inter-trial recovery time protocols provide valid methods of determining CP but not W' in cycling.

The Effects of a 6-Week Strength Training on Critical Velocity, Anaerobic Running Distance, 30-M Sprint and Yo-Yo Intermittent Running Test Performances in Male Soccer Players

The objectives of this study were to examine the effects of a moderate intensity strength training on changes in critical velocity (CV), anaerobic running distance (D'), sprint performance and Yo-Yo intermittent running test (Yo-Yo IR1) performances. Methods: two recreational soccer teams were divided in a soccer training only group (SO; n = 13) and a strength and soccer training group (ST; n = 13). Both groups were tested for values of CV, D', Yo-Yo IR1 distance and 30-m sprint time on two separate occasions (pre and post intervention). The ST group performed a concurrent 6-week upper and lower body strength and soccer training, whilst the SO group performed a soccer only training. Results: after the re-test of all variables, the ST demonstrated significant improvements for both, YoYo IR1 distance (p = 0.002) and CV values (p<0.001) with no significant changes in the SO group. 30-m sprint performance were slightly improved in the ST group with significantly decreased performance times identified in the SO group (p<0.001). Values for D' were slightly reduced in both groups (ST -44.5 m, 95% CI = -90.6 to 1.6; SO -42.6 m, 95% CI = -88.7 to 3.5). Conclusions: combining a 6-week moderate strength training with soccer training significantly improves CV, Yo-Yo IR1 whilst moderately improving 30-m sprint performances in non-previously resistance trained male soccer players. Critical Velocity can be recommended to coaches as an additional valid testing tool in soccer.

Validity and reliability of critical power field testing

PURPOSE

To test the validity and reliability of field critical power (CP).

METHOD

Laboratory CP tests comprised three exhaustive trials at intensities of 80, 100 and 105 % maximal aerobic power and CP results were compared with those determined from the field. Experiment 1: cyclists performed three CP field tests which comprised maximal efforts of 12, 7 and 3 min with a 30 min recovery between efforts. Experiment 2: cyclists performed 3 × 3, 3 × 7 and 3 × 12 min individual maximal efforts in a randomised order in the field. Experiment 3: the highest 3, 7 and 12 min power outputs were extracted from field training and racing data.

RESULTS

Standard error of the estimate of CP was 4.5, 5.8 and 5.2 % for experiments 1-3, respectively. Limits of agreement for CP were -26 to 29, 26 to 53 and -34 to 44 W for experiments 1-3, respectively. Mean coefficient of variation in field CP was 2.4, 6.5 and 3.5 % for experiments 1-3, respectively. Intraclass correlation coefficients of the three repeated trials for CP were 0.99, 0.96 and 0.99 for experiments 1-3, respectively.

CONCLUSIONS

Results suggest field-testing using the different protocols from this research study, produce both valid and reliable CP values.

Effects of Tapering on Performance

PURPOSE

The purpose of this investigation was to assess the effects of alterations in taper components on performance in competitive athletes, through a meta-analysis.

METHODS

Six databases were searched using relevant terms and strategies. Criteria for study inclusion were that participants must be competitive athletes, a tapering intervention must be employed providing details about the procedures used to decrease the training load, use of actual competition or field-based criterion performance, and inclusion of all necessary data to calculate effect sizes. Datasets reported in more than one published study were only included once in the present analyses. Twenty-seven of 182 potential studies met these criteria and were included in the analysis. The dependent variable was performance, and the independent variables were the decrease in training intensity, volume, and frequency, as well as the pattern of the taper and its duration. Pre-post taper standardized mean differences in performance were calculated and weighted according to the within-group heterogeneity to develop an overall effect.

RESULTS

The optimal strategy to optimize performance is a tapering intervention of 2-wk duration (overall effect = 0.59 +/- 0.33, P < 0.001), where the training volume is exponentially decreased by 41-60% (overall effect = 0.72 +/- 0.36, P < 0.001), without any modification of either training intensity (overall effect = 0.33 +/- 0.14, P < 0.001) or frequency (overall effect = 0.35 +/- 0.17, P < 0.001).

CONCLUSION

A 2-wk taper during which training volume is exponentially reduced by 41-60% seems to be the most efficient strategy to maximize performance gains. This meta-analysis provides a framework that can be useful for athletes, coaches, and sport scientists to optimize their tapering strategy.

The effects of cycle racing on pulmonary diffusion capacity and left ventricular systolic function

The purpose of this study was to examine the effects of a 20 km cycle race (TT) on left ventricular (LV) systolic and pulmonary function in 12 endurance cyclists. Spirometry, single-breath diffusion capacity (DLCO) with partitioning of membrane (DM) and capillary blood volume (Vc) components and 2-D echocardiograms were performed before and after the TT. During the TT mean oxygen consumption was 3.79 +/- 0.5 L x min(-1) (83 +/- 5.5% of VO2max) and mean blood lactate was 8.4 +/- 2.4 mM. Following the TT, spirometry values were unchanged, however, DLCO and DM were significantly (P<0.05) reduced. LV systolic function was increased (P<0.05) immediately after exercise, while end-diastolic area was decreased (P<0.05) at all points during recovery. The reduction in DM was correlated with LV systolic function following the TT. This relationship suggests a cardiovascular contribution to pulmonary diffusion impairment following exercise.

Performance enhancement with maintenance of resting immune status after intensified cycle training

BACKGROUND

Unaccustomed intense endurance exercise is associated with short-term suppression of natural immunity. However, it is not established whether intensified endurance training alters resting immune status or increases the risk of upper respiratory infection (URI).

PURPOSE

This study examined the effect of intensified endurance training for performance enhancement on resting immune status in nine healthy, male competitive cyclists.

DESIGN

Data were collected during 4 weeks of usual training (baseline), followed by prescribed cycle training that consisted of volume-building at customary training intensity (V phase, 6 weeks), unaccustomed very high intensity interval training at 100% maximal heart rate (I phase, 18 days), and an unloading taper (U phase, 10 days).

METHODS

The main performance criterion was a simulated 20 km time-trial. Aerobic capacity measures included power output at ventilatory threshold (POT(vent)) and maximal oxygen uptake (VO(2max)). Markers of immune status (lymphocyte subset counts, serum cytokine levels, and new URI cases) and physiological indicators of training stress (cycling economy, 24-hour urinary cortisol excretion, and serum testosterone concentration) were evaluated in the rested state, 36 to 44 hours postexercise, during baseline, and after each training phase.

RESULTS

Time-trial performance, POT9(vent), VO(2max), and cycling economy improved significantly (p < 0.001) after the V phase, and remained higher than baseline (p < 0.001) after the I and U phases. As compared with the V phase, performance time was faster after the U phase (p < 0.01). In contrast, lymphocyte counts, cytokine levels, incidence of URI, cortisol excretion, and serum testosterone concentration were not significantly different from baseline in any phase.

CONCLUSIONS

Cycling efficiency and performance improved while resting immune status was maintained throughout the 10-week training program. This study provides encouraging data in support of immunological robustness during intensified endurance training.