Blood Lactate and Maximal Lactate Accumulation Rate at Three Sprint Swimming Distances in Highly Trained and Elite Swimmers

Relationship of peak capillary blood lactate accumulation and body composition in determining the mechanical energy equivalent of lactate during sprint cycling

AIM

A 15-s all-out sprint cycle test (i.e., νLamax-test) and the post-exercise change in capillary blood lactate concentration is an emerging diagnostic tool that is used to quantify the maximal glycolytic rate. The goal of this study was to determine the relation between 15 s-work, change in capillary blood lactate concentration (∆La) and body composition in a νLamax-test.

METHOD

Fifty cyclists performed a 15 s all-out sprint test on a Cyclus2 ergometer twice after a previous familiarization trial. Capillary blood was sampled before and every minute (for 8 min) after the sprint to determine ∆La. Body composition was determined employing InBody720 eight-electrode impedance analysis.

RESULT

Simple regression models of fat-free mass (FFM) and also the product of FFM and ∆La showed similar ability to predict 15 s-work (R2 = 0.79; 0.82). Multiple regression combining both predictors explains 93% of variance between individuals. No differences between males and females were found regarding 15 s-work relative to the product of fat-free mass and ∆La. Considering pairs of similar FFM, a change 1 mmol/l of ∆La is estimated to be equal to 12 J/kg in 15 s-work (R2 = 0.85).

DISCUSSION

Fifteen s-work is both closely related to FFM and also the product of ∆La and lactate-distribution space approximated by FFM. Differences in 15 s-work between males and females disappear when total lactate production is considered. Considering interindividual differences, the mechanical energy equivalent of blood lactate accumulation seems a robust parameter displaying a clear relationship between ∆La and 15 s-work relative to FFM.

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.

Diving into Recovery. The Effects of Different Post-Competition Protocols for Enhancing Physio-Psychological Parameters in National Level Youth Swimmers

The purpose of this study was to elucidate whether a specific approach regarding active swimming recovery could better promote psycho-physiological recovery right after competing in a high-level swimming race. To achieve this, we recruited 50 national level youth swimmers, randomly and equally assigning them to two groups, named "experimental" and "coach prescribed". Each group performed a specific post-competition recovery protocol, consisting of different swimming paces, rest times, self-management of the exercises. We gathered data about blood lactate (BL), heart rate (HR), and rate of perceived exertion (RPE) at two different moments, the first moment right after the swimming competition (named post-competition phase), the second moment right after swimming the respective recovery protocol assigned (named post-recovery phase). A mixed MANOVA with Tukey HSD post-hoc analysis revealed no significant differences between the experimental and coach-prescribed groups in BL, HR, and RPE at the post-competition phase. At the post-recovery phase, however, the experimental group presented lower BL levels than the coach-prescribed group (2.40 ± 1.18 vs. 4.29 ± 2.07 mmol/L, p < 0.05). Finally, we found no interaction of swimming race ranking on recovery capacities. We conclude that for immediate improvement of BL in a wide range of high-level swimmers, an efficient recovery protocol should consist of several paces, high volumes, fixed and short rest times, whereas the widely popular self-managed, lower intensity approach does not seem as equally effective. Our study advances the development of novel recommendations for optimizing immediate fatigue management in competitive swimming.