Responses from Authors

Li Y, Niessen M, Chen X, Hartmann U. Maximal lactate steady state in kayaking. Int J Sports Med 2014; 35: 939–942

We really appreciate the kind concerns from Dr. de Lucas and his colleagues, which involves important issues in the investigation on maximal lactate steady state (MLSS).

The primary concern from Dr. de Lucas and his colleagues is the influence of test interruptions on MLSS determination. In our work [6], we also considered the possible influence of the test interruptions on the MLSS, as suggested by Beneke et al. [2]. However, in order to make our findings comparable to previous reports on MLSS in other exercise-modes, we followed the test protocol of MLSS as typically utilized [3]. Given the same test protocol of MLSS, which lasts 30 min with 30 s interruptions after each 5 min, the MLSS in kayaking (i. e., 5.4 mM) [6] is consistent with the findings as demonstrated by Beneke et al. [6]. Therefore, the fact that test interruptions have influence on MLSS [2], doesn’t not deny the relationship between MLSS and different muscle mass engaged in different exercise-modes.

We admit the influence of test interruptions on MLSS, which might be another cause of the higher MLSS (i. e., 5.4 mM) in kayaking as found in our work [6]. It would be better if we have put this interpretation in our discussion. We give our appreciations to Dr. de Lucas and his colleagues for their helpful suggestions. However, we don’t agree with the opinion from Dr. de Lucas and his colleagues, as “For continuous exercise if considering that the workload and [La] would be lower, LT4 could be used as an option”. As discussed in our work [6], the fixed lactate threshold of 4 mM originated from the investigation on MLSS in treadmill running, and to be of note, the protocol there was also with interruptions in constant-load tests [5]. With regard to the influence of test interruptions on MLSS, the 4 mM there already overestimated the MLSS in running. Utilizing an overestimated value of MLSS from running as a measure for kayaking in training diagnostics, which exercise-mode differs from running in terms of the involved muscle mass, seems unreasonable. In other words, the MLSS in kayaking from constant-load tests without interruptions might be lower than that from our work (i. e., < 5.4 mM), but this possibility could still not support the utilization of LT4 in kayaking. We do agree that the utilization of LT4 in kayaking during the previous decades have played a significant role in the training of many national and international kayak teams. However, before further investigation on MLSS in kayaking without interruptions during constant-load tests, we think that LT5 could be better than LT4 in kayaking, given the incremental test utilized in our work [6]. Actually, the German Association of Canoe Sprint (DKV) has begun to utilize the LT5 instead of the LT4 since several years ago [4].

The addition concerns from Dr. de Lucas and his colleagues is the recruitment of a small group of teenager kayakers in our study. This issue was one of our limitations, which should have been mentioned in our work. However, considering kayaking is not an “easy” sport as running or cycling, the difficulty of recruiting such kind of athletes is hoped to be understood, especially in China. Additionally, as we know, MLSS is a time-consuming test which requires the athletes to visit the laboratory 4–6 times. The MLSS test was a big challenge for their daily training. Lastly, the recruitment of teenager kayakers instead of adult kayaker was supported by the findings that MLSS is independent on age [1].

Anyway, the suggestions from Dr. de Lucas and his colleagues are sincerely appreciated. Any challenges from their research group are always welcome in order to lead our work to a more scientific direction.

• References

• 1 Beneke R, Heck H, Schwarz V, Leithäuser R. Maximal lactate steady state during the second decade of age. Med Sci Sports Exerc 1996; 28: 1474-1478
• 2 Beneke R, Hutler M, Von Duvillard SP, Sellens M, Leithäuser R. Effect of test interruptions on blood lactate during constant workload testing. Med Sci Sports Exerc 2003; 35: 1626-1630
• 3 Beneke R, von Duvillard SP. Determination of maximal lactate steady state response in selected sports events. Med Sci Sports Exerc 1996; 28: 241-246
• 4 Englert M. Untersuchungen zur Typisierung von Sportlern im Kanurennsport auf der Grundlage von leistungsdiagnostischen Untersuchungen und Trainingsdatenanalysen. Universität Leipzig 2014
• 5 Heck H, Mader A, Hess G, Mücke S, Müller R, Hollmann W. Justification of the 4-mmol/l lactate threshold. Int J Sports Med 1985; 6: 117-130
• 6 Li Y, Niessen M, Chen X, Hartmann U. Maximal lactate steady state in kayaking. Int J Sports Med 2014; 35: 935-942