+44 (0)1509 263171
Please use this identifier to cite or link to this item:
|Title: ||Effect of training strategies and creatine supplementation on performance and metabolism during sprint swimming|
|Authors: ||Peyrebrune, Michael C.|
|Issue Date: ||2001|
|Publisher: ||© Michael Peyrebrune|
|Abstract: ||Many scientific studies have considered physiological aspects of swimming, but largely in the areas of endurance or strength and power. This thesis includes six studies that
attempt to provide more information about the metabolic responses to single and
repeated sprint swimming and the physiological mechanisms behind the limitation to
sprint swimming performance.
The first experimental chapter describes the metabolic responses to single and repeated
sprinting in male and female swimmers. Peak blood lactate (male 18.7 and female 14.4
mmol 1-1;P <0.01) and ammonia (male 232.0 and female 154.3 ýtmol 1-1;P <0.05) values
following repeated swimming (8 x 50 yards) were almost double those measured during
a single 50 yards sprint and were significantly higher in males than females. It is likely
that differences in body dimensions and composition between male and female
swimmers account for the majority of the -12% performance differences and higher
metabolic response in males than females.
Energy contribution to single and repeated tethered swimming sprints was examined in
chapter V. Determination of energy contribution by an accumulated oxygen deficit test
found estimated anaerobic contribution of -67% in 30 s sprinting and -74%, -53%,
-51% and -47% during four 30 s sprint bouts. These were much lower than values
estimated previously and recommended to coaches and swimmers in popular swimming
texts. Energy contribution to 55 s maximal tethered swimming in chapter VI found
anaerobic contributions of -30-40%.
Metabolic responses to Controlled frequency breathing (CFB) have been studied
previously in endurance swimming, but not in splint swimming (chapter VI). There was
increased hypercapnia, but no significant reduction in performance during 55 s maximal
sprint tethered swimming between self-selected breathing and breathing every 10
strokes. Differences in metabolic responses (higher extraction of oxygen from inspired
air and lower ventilation, oxygen consumption, carbon dioxide production and
respiratory exchange ratio) suggest a greater efficiency during swimming with CFB.
Swimmers who can train to overcome the urge to breath should not compromise
performance, but benefit from avoiding an increase in drag resistance while turning the
head to breath.
Active recovery following intense swimming has been suggested to increase the speed
of recovery and improve subsequent performance. Chapter VII illustrates that the timing
and intensity of active recovery is crucial when prescribing repeated sets of repeated
sprint training. Lower blood lactate was matched by a tendency for poorer performance
in the trial using active recovery between repetitions. This demonstrates that the blood
lactate concentration does not reflect the metabolic state of the muscle and therefore the
ability to perform subsequent sprint swims.
Chapters VIII and IX consider the effects of creatine supplementation on sprint
swimming. No differences in single sprint swimming performance were found, but
creatine supplementation improve times in a typical training set of 8x 50 yards by -4 s.
Faster times recorded in the creatine group support the hypothesis that increasing
resting levels of creatine and phosphocreatine will enhance recovery during repeated
sprints. Supplementing with 3g creatine day-' for 22-27 weeks had no additional benefit
to race performance than just 'loading' before the training period and immediately prior
to the major swimming race of the year. It is likely that any enhanced training
adaptation would have to be from creatine supplementation allowing swimmers to
perform more training rather than just supplementation per se.
The studies in this thesis describe the physiological and metabolic responses of elite
male and female swimmers to single and repeated sprint swimming in detail for the first
time. By manipulating breathing frequency during sprinting, metabolism altered but
without compromising performance. Active recovery was successful in reducing blood
lactate concentration, but performance was poorer. The blood metabolite and respiratory
response to sprint training following interventions of this type allow us to determine the
mechanisms behind the limitation to swimming performance. Creatine supplementation
enhances repeated sprint swimming performance, but not training for success in
competition. Results of this thesis suggest that phosphocreatine availability or energy
supply are not limitations to sprint swimming training performance.|
|Description: ||Doctoral Thesis. Submitted in partial fulfillment of the requirements for the award of Doctor of Philosophy of Loughborough University.|
|Appears in Collections:||PhD Theses (Sport, Exercise and Health Sciences)|
Files associated with this item:
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.