Purpose This study aimed to investigate the effects of different work and recovery characteristics on the W′ reconstitution and to test the predictive capabilities of the W′BAL model. Methods Eleven male participants (22 ± 3 yr, 55 ± 4 mL·kg−1⋅min−1) completed three to five constant work rate tests to determine CP and W′. Subsequently, subjects performed 12 experimental trials, each comprising two exhaustive constant work rate bouts (i.e., WB1 and WB2), interspersed by an active recovery interval. In each trial, work bout characteristics (P4 or P8, i.e., the work rate predicted to result in exhaustion in 4 and 8 min, respectively), recovery work rate (33% CP or 66% CP), and recovery duration (2, 4, or 6 min) were varied. Actual (W′ACT) and model-predicted (W′PRED) reconstitution values of W′ were calculated. Results After 2, 4, and 6 min recovery, W′ACT averaged 46% ± 2.7%, 51.2% ± 3.3%, and 59.4% ± 4.1%, respectively (P = 0.003). W′ACT was 9.4% higher after recovery at 33% CP than at 66% CP (56.9% ± 3.9% vs 47.5% ± 3.2%) (P = 0.019). P4 exercise yielded a 11.3% higher W′ACT than P8 exercise (57.8% ± 3.9% vs 46.5% ± 2.7%) (P = 0.001). W′ACT was higher than W′PRED in the conditions P4-2 min (+29.7%), P4-4 min (+18.4%), and P8-2 min (+18%) (P < 0.01). A strong correlation (R = 0.68) between the rate of W′ depletion and W′ recovery was found (P = 0.001). Conclusion This study demonstrated that both the work and recovery characteristics of a prior exhaustive exercise bout can affect the W′ reconstitution. Results revealed a slower W′ reconstitution when the rate of W′ depletion was slower as well. Furthermore, it was shown that the current W′BAL model underestimates actual W′ reconstitution, especially after shorter recovery.

Purpose: The aims of this study were 1) to model the temporal profile of W′ recovery after exhaustion, 2) to estimate the contribution of changing V ˙O2 kinetics to this recovery, and 3) to examine associations with aerobic fitness and muscle fiber type (MFT) distribution. Methods: Twenty-one men (age = 25 ± 2 yr, V ˙O2peak = 54.4 ± 5.3 mL•min −1 •kg −1 ) performed several constant load tests to determine critical power and W′ followed by eight trials to quantify W′ recovery. Each test consisted of two identical exhaustive work bouts (WB1 and WB2), separated by a variable recovery interval of 30, 60, 120, 180, 240, 300, 600, or 900 s. Gas exchange was measured and muscle biopsies were collected to determine MFT distribution. W′ recovery was quantified as observed W′ recovery (W′ OBS ), model-predicted W′ recovery (W′ BAL ), and W′ recovery corrected for changing V ˙O2 kinetics (W′ ADJ ). W′ OBS and W′ ADJ were modeled using mono-and biexponential fitting. Root-mean-square error (RMSE) and Akaike information criterion (ΔAIC C ) were used to evaluate the models' accuracy. Results: The W′ BAL model (τ = 524 ± 41 s) was associated with an RMSE of 18.6% in fitting W′ OBS and underestimated W′ recovery for all durations below 5 min (P < 0.002). Monoexponential modeling of W′ OBS resulted in τ = 104 s with RMSE = 6.4%. Biexponential modeling of W′ OBS resulted in τ 1 = 11 s and τ 2 = 256 s with RMSE = 1.7%. W′ ADJ was 11% ± 1.5% lower than W′ OBS (P < 0.001). ΔAIC C scores favored the biexponential model for W′ OBS , but not for W′ ADJ . V ˙O2peak (P = 0.009) but not MFT distribution (P = 0.303) was associated with W′ OBS . Conclusion: We showed that W′ recovery from exhaustion follows a two-phase exponential time course that is dependent on aerobic fitness. The appearance of a fast initial recovery phase was attributed to an enhanced aerobic energy provision resulting from changes in V ˙O2 kinetics.

Training-intensity distribution (TID), or the intensity of training and its distribution over time, has been considered an important determinant of the outcome of a training program in elite endurance athletes. The polarized and pyramidal TID, both characterized by a high amount of low-intensity training (below the first lactate or ventilatory threshold), but with different contributions of threshold training (between the first and second lactate or ventilatory threshold) and high-intensity training (above the second lactate or ventilatory threshold), have been reported most frequently in elite endurance athletes. However, the choice between these 2 TIDs is not straightforward. This article describes the historical, evolutionary, and physiological perspectives of the success of the polarized and pyramidal TID and proposes determinants that should be taken into account when choosing the most appropriate TID.

Purpose: To analyze the physical profile and training program of a world-class lightweight double sculls rowing crew toward the Tokyo 2020 Olympics. Method: A case study in which both rowers performed physical testing in November 2020 and April 2021 (anthropometrics, incremental rowing test, and power profiling). The training program (38 wk) in the buildup to the Olympics was analyzed, providing insight into training characteristics (volume; contribution of rowing, alternative, and strength training; prescribed and recorded [heart rate] training-intensity distribution). The entire period was split into 3 phases: preparation period (8 wk), competition period 1 (11 wk), and competition period 2 (9 wk), and training characteristics were compared. Results: In the April 2021 testing, rower A (1.89 m, 74.6 kg, 4.4% body fat) had a peak oxygen uptake of 5.8 L·min−1 (77.8 mL·min−1·kg−1) and a peak power output of 491 W. Rower B (1.82 m, 70.6 kg, 7.8% body fat) had a peak oxygen uptake of 5.5 L·min−1 (77.9 mL·min−1·kg−1) and a peak power output of 482 W. The mean weekly training volume was 14 hours 47 minutes (4 h 5 min), of which 58.5% (14.6%) consisted of rowing, 13.4% (6.8%) strength training, and 28.1% (2.6%) alternative training. Heart-rate training-intensity distribution was 77.8% (4.2%) in zone 1, 16.6% (3.7%) in zone 2, and 5.6% (2.8%) in zone 3 with a lower contribution of zone 1 in competition period 1 (P = .029) and competition period 2 (P = .023) compared with the preparation period, and a higher contribution of zone 3 in competition period 1 (P = .018) and competition period 2 (P = .011) compared with the preparation period. Conclusion: The crew combined a high volume of rowing, alternative, and strength training in a pyramidal heart-rate training-intensity distribution throughout the year.

The aim of this study was to examine how respiratory (RT) and lactate thresholds (LT) are affected by acute heat exposure in the two most commonly used incremental exercise test protocols (RAMP and STEP) for functional evaluation of aerobic fitness, exercise prescription and monitoring training intensities. Eleven physically active male participants performed four incremental exercise tests, two RAMP (30 W•min -1 ) and two STEP (40 W•3 min -1 ), both in 18°C (TEMP) and 36°C (HOT) with 40 % relative humidity to determine 2 RT and 16 LT, respectively. Distinction was made within LT, taking into account the individual lactate kinetics (LTIND) and fixed value lactate concentrations (LTFIX). A decrease in mean power output (PO) was observed in HOT at LT ( -6.2 ± 1.9 %), more specific LTIND (-5.4 ± 1.4 %) and LTFIX (-7.5 ± 2.4 %), compared to TEMP, however not at RT (-1.0 ± 2.7 %). The individual PO difference in HOT compared to TEMP over all threshold methods ranged from -53 W to +26 W. Mean heart rate (HR) did not differ in LT, while it was increased at RT in HOT (+10 ± 8 bpm). This study showed that exercise thresholds were affected when ambient air temperature was increased. However, a considerable degree of variability in the sensitivity of the different threshold concepts to acute heat exposure was found and a large individual variation was noticed. Test design and procedures should be taken into account when interpreting exercise test outcomes.