Introduction
It is well known that various types of exercise induce muscle damage.
Exercise-induced muscle damage (EIMD) is recognized as the outcome of
intense to moderate physical activity (1,
2). This damage manifests itself as a
temporary decrease muscle function, increases in serum creatine kinase
(CK) and lactate dehydrogenase (LDH) concentrations, increases in
myoglobin and delayed onset muscle soreness (DOMS)
(3). The basic feature of skeletal muscle
damage without cell necrosis is the muscle fiber disruptions, chiefly
the basal lamina sheath. Regarding mechanical stimuli, especially
intense physical activity, it is understood that it can increase micro
damage in muscle fibers imposed by eccentric contractions, according to
the volume and length the damage degree and DOMS may be persist
chronically over time (4,
5). The symptoms of DOMS which include
muscle pain, strength loss, tenderness, swelling and stiffness have been
suggested to happen within 24 hours of muscle damage and last beyond
five days (6). Degradation of contractile
proteins appears to relate to reduces in muscular force about one week
to one month after eccentric exercise (7).
Due to EIMD and DOMS that follows intense, unaccustomed or eccentrically
biased exercise, a focus on recovery strategies that attenuate these
unwanted effects should be pursued. Recently, some studies indicated
that creatine consumptin might reduce post-exercise muscle damage via
mechanisms regulating mitochondrial permeability and stabilizing the
sarcolemma (8-10).
Newly, many athletes have consumed ergogenic aids to enhancing recovery,
maintain body conditioning and physiological adaptations during
long-term exercise programmes. Thus, the efficacy of ergogenic aids has
always attracted great attention, and many researchers have sought to
combine exercise training programmes and ergogenic aid to reinforce the
benefits of exercise (11,
12). Creatine is a popular and favorite
ergogenic aid at all levels among athletes that is synthesized
endogenously from the amino acids glycine, methionine and arginine or
intaked from the diet (8,
13). Articles studing the creatine
supplementation effects have demonstrated improved performance in
various exercise under a variety of different testing situation
(14, 15) ,
although this has not been shown in all studies
(16, 17).
Theoretically, enhancing the availability of phosphocreatine would
augment cellular bioenergetics of the phosphagen system
(18, 19)
in addition to the high-energy phosphates shuttling between the cytosol
and mitochondria via the creatine phosphate shuttle
(20). Also, there is evidence that
supplementation with creatine may provide benefits for patients with
diversity of neuromuscular diseases (21,
22) and metabolic disorders
(23, 24).
These results have showed that creatine supplementation may provides a
ergogenic aid for individuals and also may present some therapeutic
advantage for special populations.
In this regard, all related articles have been gathered in this study
and as far as the studies quality allows and the creatine effects on
EIMD have been evaluated. This systematic review and meta-analysis
summarizes a detailed analysis about the hypothesis that creatine
consumption can ameliorate EIMD and DOMS.