Comparison of Critical Swimming Velocity and Velocity at Lactate Threshold in Elite Triathletes

The purpose of this study was to determine whether the critical swimming velocity (Vcrit) corresponds to the velocity at lactate threshold (V-LT) in elite triathletes. Eight elite triathletes (5 male, 3 female; age 26 ± 4 years; height 1.7 ± 0.1 m and body mass 75 ± 4 kg) participated in the study. Vcrit, defined as the speed that could theoretically be maintained indefinitely without exhaustion, was expressed as the slope of a regression line between swimming distance covered and the corresponding times of five time trials over 100, 200, 400, 800 and 1500 m and all combinations of these. Lactate threshold (LT) was determined by visual inspection as the point of first inflection of the lactate-work rate curve following 5 × 300 m swims of increasing velocity which were paced using the Aquapacer (Challenge and Response, Inverurie, Scotland). Velocities of the 300 m swims were - 10, - 5, 0, + 5 and + 10 % of the average 100 m pace from a 1500 m time trial. Vcrit was similar regardless of the combination or number of time trials used in the linear regression. For all subjects Vcrit was significantly faster (p < 0.05) than V-LT (1.23 ± 0.11 m · s^-1and 1.15 ± 0.10 m · s^-1 respectively). Blood lactate concentrations were also significantly higher (p < 0.05) at Vcrit (3.0 ± 1.0 mM) than at LT (1.9 ± 0.4 mM). Results from the present study demonstrate that Vcrit can be calculated from any two time trials in triathletes, however Vcrit did not represent V-LT in triathletes. Since Vcrit is faster than V-LT it is unlikely to be sustained indefinitely and consequently the notion of Vcrit should be re-evaluated in light of these findings.

Critical velocity, lactate threshold, triathlon, swimming.

References

• 1 Bland J M, Altman D G. Statistical methods for assessing agreement between two methods of clinical measurement.  Lancet. 1986;  1 307-310
• 2 Clingeleffer A, McNaughton L R, Davoren B. The use of critical power as a determinant for establishing the onset of blood lactate accumulation.  Eur J Appl Physiol. 1994;  68 182-187
• 3 Jacobs I, Sjodin B, Kaiser P . et al . Onset of blood lactate accumulation after prolonged exercise.  Acta Physiol Scand. 1981;  112 215-217
• 4 Jenkins D G, Quigley B M. Endurance training enhances critical power.  Med Sci Sports Exerc. 1992;  24 1283-1289
• 5 Kumagai S, Tanaka K, Matsura Y, et al.. Relationships of the anaerobic threshold with the 5 km, 10 km and 10 mile races.  Eur J Appl Physiol. 1982;  49 15-23
• 6 Moritani T, Nagata A, De Vries H A, Muro M. Critical power as a measurement of physical work capacity and anaerobic threshold.  Ergonomics. 1981;  24 339-350
• 7 O'Toole M L, Douglas P S. Applied physiology of triathlon.  Sports Med. 1995;  19 251-267
• 8 Sleivert G G, Rowlands D S. Physical and physiological factors associated with success in the triathlon.  Sports Med. 1996;  22 8-18
• 9 Toussaint H M, Wakayoshi K, Hollander A P, Ogita F. Simulated front crawl swimming performance related to critical speed and critical power.  Med Sci Sports Exerc. 1988;  30 144-151
• 10 Vandewalle H, Vautier J F, Kachouri M, Lechevalier J-M, Monod H. Work-exhaustion time relationship and the critial power concept - a critical review.  J Sports Med Phys Fit. 1997;  37 89-102
• 11 Wakayoshi K, Ikuta K, Yoshida T, Udo M, Moritani T, Mutoh Y, Miyashita M. Determination and validity of critical velocity as an index of swimming performance in the competitive swimmer.  Eur J Appl Physiol. 1992;  64 153-157
• 12 Wakayoshi K, Yoshida T, Udo M, Kasai T, Moritani T, Mutoh Y, Miyashita M. A simple method for determiming critical speed as swimming fatigue threshold in competitive swimming.  Int J Sports Med. 1992;  13 367-371
• 13 Wakayoshi K, Yoshida T, Udo M, Harada T, Moritani T, Mutoh Y, Miyashita M. Does critical swimming velocity represent exercise intensity at maximal lactate steady state?.  Eur J Appl Physiol. 1993;  66 90-95
• 14 Weltman A, Snead D, Stein P, Seio R, Schurrer R, Rutt R, Weltman J. Reliability and validity of a continuous incremental treadmill protocol for the determination of lactate threshold, fixed blood lactate concentrations, and V˙O₂max.  Int J Sports Med. 1990;  11 26-32
• 15 Wright B, Smith D J. A protocol for the determination of critical speed as an index of swimming endurance performance. In: Miyashita M, Mutoh Y, Richardson AB (eds) Med Sci Aquatic Sports. Basel; Karger 1994: 55-59