Biomechanics and Medicine in Swimming XI

found. This pattern has previously been described (Avlonitou, 1996;
Bonifazi et al., 1993) and reflects the energetic demands for each distance.
Because of the short duration of 50 m races (~20 s) the ATP-PC
system is able to supply a substantial proportion of the energy needed
for these events, thus blood lactate concentration was lower in comparison
to 100-800 m events. Within the 50 m events, post-race [BLa]
was lowest for breaststroke and highest for butterfly. Our findings that
the highest post-race [BLa] were observed following the 100 and 200
m races was not surprising as other researchers have reported similar
outcomes in elite (Bonifazi et al., 1993; Bonifazi et al., 2000) and college
swimmers (Sawka et al., 1979). Thus, even though it is estimated that a
large proportion of the energy supplied for events of this duration comes
from oxidative metabolism substantial blood lactate accumulation occurs
during these events.
Table 2. Suggested active recovery distances
Event
Freestyle
Men Women
50 1000-1200 600-800
100 1300-1500 800-1000
200 1300-1500 800-1000
400 1300-1500 800-1000
800 1000-1200 600-800
1500
Backstroke
800-1000 600-800
50 1000-1200 600-800
100 1300-1500 1000-1200
200
Breaststroke
1300-1500 1000-1200
50 800-1000 500-800
100 1200-1400 800-1000
200
Butterfly
1200-1400 800-1000
50 1200-1400 700-900
100 1200-1400 800-1000
200
Individual Med.
1200-1400 800-1000
200 1200-1400 800-1000
400 1200-1400 800-1000
Sex differences in post-race [BLa] have been reported for top level
(Bonifazi et al., 1993) and age group (Avlonitou, 1996) swimmers, but
not all events display a substantial disparity between men and women
(Avlonitou, 1996; Bonifazi et al., 1993). The post-race [BLa] distribution
curve is shifted to the right for males compared to females (Bonifazi
et al., 1993) and [BLa] tends to be about 1 mmol•L -1 higher in most
events for men (Avlonitou, 1996). A sex difference existed in post-race
[BLa] only following freestyle events with male swimmers achieving a
greater [BLa] compared to women. Only female swimmers competed
in, and were subsequently evaluated after, the 1500 m freestyle event,
which had the lowest mean post-race [BLa]. However the sex difference
persisted even when the outcomes from the 1500 m freestyle event were
removed from the analysis.
Previous research has reported post-race [BLa] tend to be greater
following IM events, whereas breaststroke tends to result in lower [BLa]
regardless of age or sex (Avlonitou, 1996; Bonifazi et al., 1993; Sawka et
al., 1979). Interestingly, our male swimmers had similar post-race [BLa]
across all swim strokes. In contrast, the female swimmers displayed a
7-21% greater post-race [BLa] for IM events compared to freestyle,
breaststroke and butterfly races. The lack of difference between strokes
for males is unclear, however the observed relative difference between
chaPter3.PhysioLogyandBioenergetics
IM and other strokes for females is similar, albeit on the lower end,
to others who demonstrated a 25-60% greater post-race [BLa] for IM
compared to other strokes of equal distance in age group (Avlonitou,
1996) and college (Sawka et al., 1979) swimmers.
Swimmers in the current study completed an active recovery according
to their individual coach’s assigned protocol. While not experimentally
optimal, it reflects the reality of swim meets, and thus the recovery
distances recommended in this paper may be more widely implemented
than if the protocols were rigidly controlled. As an example of the utility
of our model, if a female swimmer competed in the 200 m freestyle final
and had a post-race [BLa] of 12.5 mmol•L -1 , an active recovery of 600
m or 1200 m would be expected to reduce [BLa] by 9.5 mmol•L -1 and
11.3 mmol•L -1 , respectively, which would result in a post active recovery
[BLa] of 3.0 mmol•L -1 or 1.3 mmol•L -1 . Taken together with the findings
of Greenwood et al. (Greenwood et al., 2008)and subsequent swimming
performance, coaches can now specify the distance and intensity of
the active recovery to maximize blood lactate clearance.
conclusIon
The results of a comprehensive analysis of blood lactate levels across a
range of swimming events are reported. Furthermore, an estimate of lactate
clearance by gender and event which is a practical tool for coaches
is presented.
reFerences
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Greenwood, J. D., Moses, G. E., Bernardino, F. M., Gaesser, G. A.,
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AcKnoWledGeMents
Funding provided by Canadian Sport Centre Ontario. Thanks to R.
Rupf, E. Fernandez, C. Dalcin, T. Zochowski, S Farra.
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