Rawson and colleagues [7] supplemented male subjects with Cr for 5 days prior to 50 maximal eccentric contractions. The study showed that maximal isometric force of the elbow flexors, and serum creatine kinase (CK) and lactate dehydrogenase (LDH) activity, in response to eccentric exercise were not significantly different between the Cr-supplemented and control groups during the 5 days following exercise.

Therefore, it was suggested that Cr supplementation does not reduce indirect markers of muscle damage or enhance recovery from high-force eccentric exercise. Similarly, Warren et al. [8] demonstrated that recovery of mouse anterior crural muscle strength after damage (induced Selleckchem LY333531 by 150 eccentric contractions) was unaffected RXDX-101 following 2-weeks of

Cr supplementation. Following 3 minutes recovery, there was no effect on isometric strength or on torque loss at any eccentric or concentric angular velocity. However, a number of limitations exist with this study. Firstly, researchers were only interested in how increased muscle Cr influenced peak strength loss and not the recovery of strength per se after injury. Therefore, the 3 min recovery period may not be long enough to see any beneficial effect of Cr supplementation on muscle strength loss. Secondly, Cr supplementation may have attenuated other markers of muscle damage such as blood concentrations of myocellular proteins. However, since injury assessment was only muscle function based, these were not measured. The effect of Cr supplementation upon inflammatory and muscle soreness markers has also been examined following prolonged running [5]. Experienced marathon runners were supplemented (4 doses of 5 g of Cr) for 5 days prior to a 30 km race. Blood samples were collected pre-race, and 24 hours following the end of the test, to measure for CK, LDH, prostaglandin

E2 (PGE2) and TNFalpha (TNF-α). Farnesyltransferase Athletes from the control group presented an increase in all muscle soreness markers, indicating a high level of cell injury and inflammation, while Cr supplementation significantly attenuated these increases, with the exception of CK. However, while this Cr supplementation protocol may be an effective strategy in maintaining muscle integrity during and after intense prolonged aerobic exercise, it may not be sufficient to protect muscle fibres from more damaging exercises, such as those shown by Rawson et al. [7]. Therefore, the purpose of this investigation was to supplement a group of healthy participants with either Cr or a placebo prior to, and in the days after a single bout of eccentric exercise. The extent of, and recovery from, damage was evaluated by the following established, indirect markers of exercise-induced muscle damage; knee extension/flexion force development (MVC), and plasma CK and LDH activity [9, 10].