Home > Journals > The Journal of Sports Medicine and Physical Fitness > Past Issues > The Journal of Sports Medicine and Physical Fitness 2003 December;43(4) > The Journal of Sports Medicine and Physical Fitness 2003 December;43(4):481-7

CURRENT ISSUE
 

ARTICLE TOOLS

Reprints

THE JOURNAL OF SPORTS MEDICINE AND PHYSICAL FITNESS

A Journal on Applied Physiology, Biomechanics, Preventive Medicine,
Sports Medicine and Traumatology, Sports Psychology


Indexed/Abstracted in: Chemical Abstracts, CINAHL, Current Contents/Clinical Medicine, EMBASE, PubMed/MEDLINE, Science Citation Index Expanded (SciSearch), Scopus
Impact Factor 1,215


eTOC

 

Original articles  SPORT NUTRITION AND SUPPLEMENTATION


The Journal of Sports Medicine and Physical Fitness 2003 December;43(4):481-7

Copyright © 2009 EDIZIONI MINERVA MEDICA

language: English

Effects of creatine loading on muscular strength and endurance of female softball players

Ayoama R., Hiruma E., Sasaki H.

Human Performance Laboratory, Department of Sports Sciences and Management, School of Human Science, Osaka International University, Osaka, Japan


PDF  


Aim. The pur­pose of ­this ­study was to deter­mine the ­effects of Cr sup­ple­men­ta­tion on ­muscle ­strength and endu­rance of the ­trained ­females, the ­effect of anaer­obic exer­cises per­formed ­before the sup­ple­men­ta­tion and dis­ap­pear­ance of the ­effects on the per­for­mance.
­Methods. ­Twenty-six col­le­giate ­female soft­ball ­players ­were ­divided ­into the Cr1, 2, Con­trol (­Cont.)1 or 2 ­group, ran­domly. ­They per­formed max­imal 2-iso­metric and 30-iso­ki­netic ­knee exten­sions at the ­angular veloc­ities of 180° and 60°/s. There­after, the sub­jects of the Cr2 and ­Cont.2 ­groups per­formed resis­tance exer­cises ­with 10 RM and ­cycling ­with 0.01 kg . kg-1 ­body ­weight, alter­nately ­during the 1st ­week. ­During the 2nd ­week, the sub­jects of the Cr1 and 2 ­groups ­ingested 20 g Cr a day for 1 week. There­after, the sub­jects in the Cr2 ­group con­tinued 3 g Cr inges­tion a day for 2 weeks ­while the Cr1 ­group ­ingested the ­same ­amount of pla­cebo ­during the 3rd and 4th ­weeks. The sub­jects of the ­Cont.1, 2 ­groups ­ingested the ­same ­amount and ­taste of pla­cebo ­during the 1st to 4th ­weeks. ­This ­study was under­gone in ­double ­blind ­fashion. The sim­ilar meas­ure­ments, to ­which the sub­jects per­formed the 1st day, ­were car­ried out on the ­final day of the 2nd, 3rd and 4th ­weeks.
­Results. ­Though max­imal iso­metric ­strength did not ­differ in ­intra- and ­inter­groups, the iso­ki­netic ­peak ­torque in the Cr1 ­group was sig­nif­i­cantly ­decreased in the 4th meas­ure­ment (p<0.01). The ­mean ­torque of the 1st to 10th ­knee con­trac­tions at 60°/s was sig­nif­i­cantly ­decreased ­from the 2nd meas­ure­ment in the ­Cont.1, 2 ­groups, com­pared ­with ­that in the 1st meas­ure­ment (p<0.01). In the Cr ­groups, the sig­nif­i­cant ­decrease was ­detected ­from the 3rd in the Cr1 and in the 4th meas­ure­ment in the Cr2 ­group. The ­mean ­torque of the ­latter 20 con­trac­tions at 180°/s was sig­nif­i­cantly ­increased in the Cr2 ­group (p<0.001). In the 1st meas­ure­ment, the ­mean ­torque in the Cr1 ­group was sig­nif­i­cantly ­higher ­than ­that in the Cr2 ­group (p<0.05). How­ever, the dif­fer­ences ­between Cr1 and 2 ­groups ­were not ­detected ­from the 2nd meas­ure­ment.
Con­clu­sion. Twenty g Cr sup­ple­men­ta­tion a day for a ­week to the ­trained ­females ­improves not the max­imal ­static ­strength and ­dynamic ­peak ­torque but the ­mean ­strength and endu­rance of ­repeated con­trac­tions. How­ever, the ­effects on ­females are not so ­great as ­that ­ever ­found in ­males. The ­effects are ­enhanced by anaer­obic exer­cises per­formed ­before the sup­ple­men­ta­tion and ­would dis­ap­pear in a ­week if the sup­ple­men­ta­tion ­were ­stopped.

top of page

Publication History

Cite this article as

Corresponding author e-mail