| dc.description.abstract | The main purpose of this thesis was to investigate the influence of muscle fiber
type composition and supplemental creatine monohydrate on repeated bouts of the
Wingate Anaerobic Test (WAnT). More specifically, would a higher percentage of Type
II muscle fibers demonstrate a greater significant improvement in repeated bouts of cycle
ergometry after creatine supplementation. Nineteen males (mean ± SD age, body mass,
and height = 21.7 ± 1.9 yr., 84.1 ± 14.1 kg and 161.5 ± 7.8 cm, respectively) participated
in the 13 day experiment. Initially, sixty-five participants performed a single 30-s WAnT
against a resistance of .10 kg/kg body weight. All scores were then rank ordered from
highest to lowest, according to relative peak anaerobic power (PAPr) scores. Ten
participants from both ends of this distribution were approached and requested to
volunteer for the remainder of the study. This allowed the following four groups to be
constructed: 1) high WAnT with creatine (n = 5), 2) high WAnT with placebo (n = 5), 3) low WAnT with creatine (/i = 5), and 4) low WAnT with placebo (n = 4). On days 4 and
12 of the study, percutaneous muscle biopsies were obtained from the vastus lateralis and
stained histochemically to determine fiber type distribution (Type II, IIa, and Ilb). This
data demonstrated a positive, but weak relationship between peak anaerobic scores
(relative) obtained during the single 30-s WAnT and percent type II muscle fibers
(r = 0.52, p<0.05). Furthermore, a Spearman rank-order correlation revealed a positive
monotonic relationship (R = 0.611, p<0.01) between the variables. Finally, a 2 x 2
factorial ANOVA (F (1,15) = 12.8, p<0.01), revealed that the 10 participants within the
high PAPr group had higher values for %FT, regardless of treatment. This data revealed
that the grouping of participants according to PAPr during the single 30-s WAnT was
reflective of their fiber type distribution in regards to percent type II muscle fibers. Five
repeated bouts of the WAnT were performed on days 5 and 12 of the study, with each
bout lasting 15-s, against a resistance o f0.075 kg/kg body weight and with 45-s of active
rest between each bout. Supplementation occurred on days 7 through 11, with groups # 1
and #3 receiving the treatment (4 x 5g of creatine + 2g of dextrose powder) and groups
# 2 and # 4 receiving the placebo (4 x 7g of dextrose powder). Peak anaerobic power
(absolute and relative), mean anaerobic power (absolute and relative) and percent power
decrease were recorded during each of the five bouts. The design was a 2 (time: pre or
post) by 2 (treatment: creatine or placebo) by 2 (WAnT: high or low) by 5 (bouts; 1
through 5) split-plot factorial analysis. Change scores were calculated for all five
dependent measures and consequently the data was analyzed with a 2 (treatment; creatine
or placebo) by 2 (WAnT: high or low) by 5 (bouts: 1 through 5) split-plot factorial
ANOVA, which revealed no significant main or interaction effects. Furthermore, there was a significant increase in body weight, from pre to post-supplementation, regardless of
treatment. The results therefore, suggest no relationship between participants' fiber type
distribution (through the stated relationship to PAPr), creatine supplementation, and
repeated bouts of the WAnT. However, due to the small number of participants per cell
or group within this study, the results should be viewed with caution. | |
