Bonifazi, M., Martelli, G., Marugo, L., Sardella, F., & Carli, G. (1993). Blood lactate accumulation in top level swimmers following competition. The Journal of Sports Medicine and Physical Fitness, 33, 13-18.

Top Italian swimmers (M = 116, F = 87) were assessed for lactate levels at the end of short-course competitive efforts. The sample actually contained a wide range of performance abilities and may be accurately described as being heterogeneous in performance capability.

Several lactate assessments were performed. One of particular interest was the evaluation of speeds corresponding to 4 mM/l lactate value. The authors considered this to be the criterion speed for aerobic capacity. Measures and performance were correlated.

Relationships between V 4 mM/l and competition distance swims were found but not for 50 and 100 m events. Other parameters (e.g., mechanical power of stroking, distance per stroke) might be critical for the sprint distances. The relationships were as follows:

• r = .72 - 200 m males,
• r = .87 - 400 m males,
• r = .91 - 1500 m males,
• r = .86 - 400 m females, and
• r = .84 - 800 m females.

There was considerable variance among the subjects in lactate accumulations for both sexes. Females recorded lower values than males at all distances. [This agrees with Howat and Robson.]

The lactate values of swimmers are much lower than in running for the same duration. The difference is attributable to swimming having a smaller active muscle mass, lower maximal oxygen uptake, increased muscle blood flow during work, and a different body position.

The differences between males and females can be explained on the bases that females (a) display an inborn glycogen-sparing metabolic profile, (b) have less pronounced glycolytic activity in skeletal muscle, (c) have a higher capacity for lactate oxidation, and (d) have a smaller active muscle mass.

Implications. The swimming speed that is achieved when lactate levels correspond to 4 mM/l may be a reasonable predictor of preparedness to swim a particular time for an endurance event. However, the correlation coefficients, although high, are not of sufficient size to make critical determinations of training based on that one test. For those who are interested, the V 4 mM/l test is conducted as follows.

1. Two 400 m constant speed swims are performed with a 20 min rest interval between them.
2. The first repetition is at 85% of maximum 400 m speed, and the second at 100%.
3. Lactate values are obtained before and 1, 3, 5, and 7 min after each repetition.
4. The individual linear relationship between peak lactate values and swimming speeds is determined and the velocity corresponding to 4 mmol/l lactate is calculated/interpolated.
5. The calculated speed is the criterion for aerobic capacity for swimmers.

It should be noted that these relationships were derived from a group with considerable variation in performance and capacity, that is, it was heterogeneous. Relationships such as those of this study would not exist in a group of very good swimmers who had only a small amount of capacity and performance diversity. Thus, it is prudent to conclude that the implications from this study ARE NOT appropriate for homogeneous groups of elite swimmers. The statistics used would not reveal the same relationship because the statistics are dependent upon a large range of measures. A large range of measures does not exist in small groups of elite swimmers.

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