Unformatted text preview: group or
group by time interaction for any of the variables
measured. These results suggest that Cr supplementation does not lessen the symptoms associated eccentric exercise and the hypothesis that Cr may
decrease membrane fluidity and increase membrane
stability was not supported.
2.2.1 Jumping and Sprinting Cr supplementation has been reported to increase
both peak and mean power output during countermovement vertical jumps (CMVJ) and static jumps
(SJ). Haff et al. examined the effects of a
6-week resistance training programme plus Cr supplementation on dynamic rates of force development during jumping activities. Thirty-six well
trained athletes (16 males and 20 females) were
randomly assigned into a Cr group (n = 15; 0.3 g/kg
BW for 6 weeks) or a placebo group (n = 21).
Resistance training sessions were carried out three
days/week utilising primarily high-power ballistictype exercises (power cleans, power snatches) and
sprint training on the other two days. Testing consisted of performing maximal CMVJ and SJ so that
force-time curve characteristics such as displacement, peak force and rate of force development
could be recorded. Both groups had significant improvements regarding force-time curve characteristics for the SJ following training. However, a significant group by time interaction indicated that the Cr
Sports Med 2005; 35 (2) The Effects of Creatine in Sport and Exercise group had a greater rate of improvement for CMVJ
height when compared with the placebo group.
Izquierdo et al. investigated the potential
ergogenic effects of Cr supplementation on muscle
power, endurance, fatigue and sprint performance.
Nineteen previously resistance-trained male handball players were randomly assigned to either a Cr (n
= 9; 20 g/day for 5 days) or placebo (n = 10) group.
Maximal strength was assessed using a half squat
and bench press, while maximal repetitive highpower output was also determined for the half squat
(70% 1RM) and bench press (60% 1RM) by performing one set of ten repetitions followed by a
2-minute rest period, then a second set until muscular failure. Lifting cadence was controll...
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