Time limit and V̇O2 kinetics at maximal aerobic velocity: Continuous vs. intermittent swimming trials

Abstract

The time sustained during exercise with oxygen uptake (V̇O2) reaching maximal rates (V̇O2peak) or near peak responses (i.e., above second ventilatory threshold [t@VT2) or 90% V̇O2peak (t@90%V̇O2peak)] is recognized as the training pace required to enhance aerobic power and exercise tolerance in the severe domain (time-limit, tLim). This study compared physiological and performance indexes during continuous and intermittent trials at maximal aerobic velocity (MAV) to analyze each exercise schedule, supporting their roles in conditioning planning. Twenty-two well-trained swimmers completed a discontinuous incremental step-test for V̇O2peak, VT2, and MAV assessments. Two other tests were performed in randomized order, to compare continuous (CT) vs. intermittent trials (IT100) at MAV until exhaustion, to determine peak oxygen uptake (Peak-V̇O2) and V̇O2 kinetics (V̇O2K). Distance and time variables were registered to determine the tLim, t@VT2, and t@90%V̇O2peak tests. Blood lactate concentration ([La−]) was analyzed, and rate of perceived exertion (RPE) was recorded. The tests were conducted using a breath-by-breath apparatus connected to a snorkel for pulmonary gas sampling, with pacing controlled by an underwater visual pacer. V̇O2peak (55.2 ± 5.6 ml·kg·min−1) was only reached in CT (100.7 ± 3.1 %V̇O2peak). In addition, high V̇O2 values were reached at IT100 (96.4 ± 4.2 %V̇O2peak). V̇O2peak was highly correlated with Peak-V̇O2 during CT (r = 0.95, p < 0.01) and IT100 (r = 0.91, p < 0.01). Compared with CT, the IT100 presented significantly higher values for tLim (1,013.6 ± 496.6 vs. 256.2 ± 60.3 s), distance (1,277.3 ± 638.1 vs. 315.9 ± 63.3 m), t@VT2 (448.1 ± 211.1 vs. 144.1 ± 78.8 s), and t@90%V̇O2peak (321.9 ± 208.7 vs. 127.5 ± 77.1 s). V̇O2K time constants (IT100: 25.9 ± 9.4 vs. CT: 26.5 ± 7.5 s) were correlated between tests (r = 0.76, p < 0.01). Between CT and IT100, tLim were not related, and RPE (8.9 ± 0.9 vs. 9.4 ± 0.8) and [La−] (7.8 ± 2.7 vs. 7.8 ± 2.8 mmol·l−1) did not differ between tests. MAV is suitable for planning swimming intensities requiring V̇O2peak rates, whatever the exercise schedule (continuous or intermittent). Therefore, the results suggest IT100 as a preferable training schedule rather than the CT for aerobic capacity training since IT100 presented a significantly higher tLim, t@VT2, and t@90%V̇O2peak (∼757, ∼304, and ∼194 s more, respectively), without differing regards to [La−] and RPE. The V̇O2K seemed not to influence tLim and times spent near V̇O2peak in both workout modes.

Oxygen Uptake Kinetics and Time Limit at Maximal Aerobic Workload in Tethered Swimming

“…However, even among elite swimmers with high VO 2peak (>70 mL•kg −1 •min −1 ), the time limit values at maximal aerobic velocity presented a wide range (188 to 400 s) [21]. Moreover, evidence of the inverse association between time limit and maximal aerobic velocity, which was supported for cycling, running, swimming flume [37], and unimpeded front crawl swimming [25,37,38], with coefficients ranging from r = −0.47 to −0.72, was also found in the current study for tethered swimming. Additionally, the current study demonstrated an inverse association of t Lim with other indexes of aerobic conditioning (such as VO 2peak , GET, and RCP) and the VO 2 elevation at the end of performance (such as EEVO 2 ).…”

“…In contrast, in the context of constant exercise, there is a lack of information to support the physiological description of rest-to-work transition during tethered swimming, which might be useful to provide the necessary metabolic adjustment to reach muscular energy requirements, as has been observed by means of VO 2 kinetics (VO 2 k) in unimpeded swimming for the characterization of exercise domains [ 14 , 15 ], performance in distance races [ 16 , 17 , 18 ], exercise tolerance (i.e., time limit) in continuous [ 19 , 20 , 21 , 22 , 23 ] and intermittent trials [ 24 , 25 ], and comparisons to other exercises modes [ 26 ]. In fact, there are findings comparing constant exercise performance and blood-lactate response during tethered to unimpeded swimming conditions [ 7 ], but the VO 2 k was not analyzed and therefore not compared.…”

Stroke and physiological relationships during the incremental front crawl test: outcomes for planning and pacing aerobic training

“…Swimming is a sport that requires high technical proficiency, which, alongside the cost of swimming, is a factor that will decisively determine the training and competition performance ( Wakayoshi et al, 1995 ; Silveira et al, 2019 ; Zacca et al, 2020 ). In training planning, it is important to incorporate the energetic balance that aligns with the specific race requirements when determining the duration of work intervals ( Zamparo et al, 2005 ; Almeida et al, 2021 ), and swimming coaches should also assume that the time limit and maximal aerobic velocity (MAV) are influenced by stroking parameters ( Wakayoshi et al, 1993 ; Almeida et al, 2022 ). In this sport, integrating precise measurements with less time-consuming or intrusive methods supports the ongoing exploration of applied exercise physiology in sports training ( Espada et al, 2015 ; Zacca et al, 2019 ).…”

Body Composition Relationship to Performance, Cardiorespiratory Profile, and Tether Force in Youth Trained Swimmers

“…Research in sports has been searching for methodologies that are less time-consuming and that, at the same time, use instruments that are not only at specific training facilities but that allow portability, which is particularly important in sports with a highly competitive density and that take place in environments that pose constraints to regular training control, as is the case with swimming. Despite the assumption that body composition plays an important role in sports [ 1 ], particularly in swimming, where body composition control was shown to be a valuable tool to optimize competitive performance through monitoring the efficiency of body adaptation to the training process [ 2 ], most research has focused on biomechanical and physiological evaluation [ 3 , 4 , 5 , 6 , 7 , 8 ], since these have been considered and assumed as performance indicators in this specific sport, which is quite demanding for athletes from a training point of view.…”