SPURIOUS VALIDATION OF LACTATE THRESHOLD TEST IN SWIMMING
Barber, J. W., Williford, H. N., Duey, W. J., Pieri, S. R., & Barksdale, J. (1997). Validation of the T-30 and swimming step test in adolescent competitive swimmers. Medicine and Science in Sports and Exercise, 29(5), Supplement abstract 289.
This study compared a 30 min timed swim test (T-30) and the swimming step test with a blood lactate test to determine anaerobic threshold training speeds in competitive swimmers.
Ss (M = 5; F = 5) performed each test to determine the swimming speed at which the lactate/anaerobic threshold was evidenced.
Results showed that the step test (v = 1.39 m/sec) correlated with the lactate threshold test (v = 1.41 m/sec; r = .94) while the T-30 swim (v = 1.29 m/sec) correlated r = .84. This indicated that the step test was associated more with the lactate threshold protocol than the T-30 swim.
These results are not surprising but they should be viewed cautiously. They do not indicate that the swimming step test is valid for assessing or predicting lactate threshold in swimming. It is only valid for predicting the particular characteristics of the lactate threshold protocol used in this study.
It is now generally conceded that lactate threshold is dependent upon the protocol and determining criteria used. For trained athletes, the 4 mM criterion is not well accepted. Since the swimming step test and the lactate threshold test both used intermittent incremental protocols they are likely to be more alike than with the continuous task of the T-30 swim. The results obtained are also a product of the threshold criterion. If a different lactate threshold criterion was employed the sizes of the correlations most likely would have been different. Thus, the results of this study are an artifact of its design. A better design would have been to correlate step test and T-30 results with several protocols that yield different lactate/anaerobic threshold values to see if results are robust across (independent of) different assessment protocols.
Implication. Research design problems involved with the concepts employed in this study do not allow one to conclude that the swimming step test is a better predictor of appropriate training speeds than the T-30 swim.
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