Is Functional Overreaching or Acute Fatigue the Key to the Effects of Concentrated Block Training in Running?

ABSTRACT: Borszcz, FK, Vieira, MT, Tramontin, AF, Visentainer, LH, and Costa, VP. Is functional overreaching or acute fatigue the key to the effects of concentrated block training in running? J Strength Cond Res 36(12): 3485-3496, 2022-This study examined the effects of 5 consecutive days of high- and moderate-intensity training on performance and physiological measures in moderately trained individuals. The relationship of the training organization with the state of overreaching and acute fatigue was investigated. Twenty-four male soldiers (age, 19.3 ± 0.4 years; V̇o2peak, 58.7 ± 3.8 ml·kg-1·min-1) were assigned to 2 training groups for 5 consecutive days of either high- or moderate-intensity training. The subjects underwent incremental and 12-minute time trial tests before, immediately after, 1 and 2 weeks after training. The high- and moderate-intensity sessions were 30 minutes in duration and performed at fixed velocities of 13.3 and 10 km·h-1 (near second and first ventilatory thresholds), respectively. Acute fatigue and overreaching criteria were set as concomitant nonimpairment and impairment, respectively, in the incremental peak velocity and 12-minute time trial performances at posttest immediately after the training block. Data analyses were completed using hierarchical Bayesian's models. In subjects who wer trained at moderate intensity, no performance impairment occurred (i.e., acute fatigue); for the high-intensity training, 5 subjects showed impairment in performance and were classified as overreached. Only in subjects who were acutely fatigued, clear beneficial effects were observed in incremental test peak velocity and 12-minute time trial performances. In moderately trained runners, a block of 5 consecutive days of moderate-intensity training was demonstrated to be a useful strategy for the improvement of performance. However, high-intensity training does not seem to be a safe strategy because of the observations of overreaching and inferior probabilities of performance improvements.

Validity and Reliability of the PowerCal Device for Estimating Power Output During Cycling Time Trials.

Costa, VP, Guglielmo, LGA, and Paton, CD. Validity and reliability of the PowerCal device for estimating power output during cycling time trials. J Strength Cond Res 31(1): 227-232, 2017-This study assessed the validity and reproducibility of the PowerCal device for estimating power output (PO) during cycling hilly time trials (TTs). Twenty-one well-trained men cyclists performed an incremental exercise test and three 20-km TTs (34.1 ± 10.6 years; 73.2 ± 3.2 kg, 176.8 ± 6.2 cm; maximal PO, 334 ± 31 W; maximal oxygen uptake, 61.0 ± 4.2 ml·kg·min). The first TT was used for familiarization, and the tests were separated by at least 72 hours. Mean PO over the 20-km TT was significantly greater for the Velotron (282 ± 27 W) than for the PowerCal (242 ± 28 W). The mean power over each kilometer of the trial ranged from 5.8 to 23.4% greater on the Velotron than on the PowerCal. High within-subject variation between the trials was substantially greater for the PowerCal (4.9%) than for the Velotron (1.8%). High coefficients of variation scores for the Velotron test-retest were found to be concentrated in the beginning and final meters of the TT (∼6.0%), whereas the scores were lower in the middle of the trials (∼3.0%). In contrast, the PowerCal test-retest achieved a high coefficient of variation (∼6.0%) in each km over the TT. Thus, the PowerCal device should be used with caution during cycling activities because it is not reliable and underestimates PO.

Physiological Correlations With Short, Medium, and Long Cycling Time-Trial Performance.

PURPOSE: Several studies have demonstrated that physiological variables predict cycling endurance performance. However, it is still unclear whether the predictors will change over different performance durations. The aim of this study was to assess the correlations between physiological variables and cycling time trials with different durations. METHODS: Twenty trained male cyclists (maximal oxygen uptake [VO2max] = 60.5 ± 5.6 mL/kg/min) performed 4 separate experimental trials during a 2-week period. Cyclists initially completed an incremental exercise test until volitional exhaustion followed by 3 maximal cycling time trials on separate days. Each time trial consisted of 3 different durations: 5 min, 20 min, and 60 min performed in a randomized order. RESULTS: The main results showed that the physiological measures strongly correlated with long cycling performances rather than short and medium time trials. The time-trial mean power output was moderately high to highly correlated with peak power output and VO2max (r = .61-.87, r = .72-.89, respectively), and was moderately to highly correlated with the lactate threshold Dmax method and second ventilatory threshold (r = .52-.75, r = .55-.82, respectively). CONCLUSIONS: Therefore, trained cyclists should develop maximal aerobic power irrespective of the duration of time trial, as well as enhancements in metabolic thresholds for long-duration time trials.

Effects of a seven day overload-period of high-intensity training on performance and physiology of competitive cyclists.

OBJECTIVES: Competitive endurance athletes commonly undertake periods of overload training in the weeks prior to major competitions. This investigation examined the effects of two seven-day high-intensity overload training regimes (HIT) on performance and physiological characteristics of competitive cyclists. DESIGN: The study was a matched groups, controlled trial. METHODS: Twenty-eight male cyclists (mean ± SD, Age: 33±10 years, Mass 74±7 kg, VO2 peak 4.7±0.5 L·min-1) were assigned to a control group or one of two training groups for seven consecutive days of HIT. Before and after training cyclists completed an ergometer based incremental exercise test and a 20-km time-trial. The HIT sessions were ∼120 minutes in duration and consisted of matched volumes of 5, 10 and 20 second (short) or 15, 30 and 45 second (long) maximal intensity efforts. RESULTS: Both the short and long HIT regimes led to significant (p<0.05) gains in time trial performance compared to the control group. Relative to the control group, the mean changes (±90% confidence limits) in time-trial power were 8.2%±3.8% and 10.4%±4.3% for the short and long HIT regimes respectively; corresponding increases in peak power in the incremental test were 5.5%±2.7% and 9.5%±2.5%. Both HIT (short vs long) interventions led to non-significant (p>0.05) increases (mean ± SD) in VO2 peak (2.3%±4.7% vs 3.5%±6.2%), lactate threshold power (3.6%±3.5% vs 2.9%±5.3%) and gross efficiency (3.2%±2.4% vs 5.1%±3.9%) with only small differences between HIT regimes. CONCLUSIONS: Seven days of overload HIT induces substantial enhancements in time-trial performance despite non-significant increases in physiological measures with competitive cyclists.