Having a spotter nearby is particularly important when using free weights. Even someone in great shape sometimes just can't make that last rep. It's no big deal if you're doing biceps curls; all you'll have to do is drop the weight onto the floor. But if you're in the middle of a bench press — a chest exercise where you're lying on a bench and pushing a loaded barbell away from your chest — it's easy to get hurt if you drop the weight. A spotter can keep you from dropping the barbell onto your chest.
Anti-cancer effects have been observed with the creatine analogue cyclocreatine[456][104][457] and have been replicated with creatine itself. These effects tend to be a reduction in which the rate of implanted tumors progresses.[458][459] It is suspected that these observed effects (inhibition of growth or attenuation of the rate of growth) are not due to the bioenergetic effect of creatine, secondary to creatine kinase. These anti-cancer effects do not have a known reliability, as the expression of creatine kinase varies widely based on the type of tumor.[460] However, some studies suggest an inverse relationship between tumor progression in mice and concentrations of creatine in cells, with creatine depletion coinciding with tumor development.[460]
The first open label trial on ALS failed to significantly alter lung function as assessed by FEV (when comparing the rate of decline pretreatment relative to treatment).[545] Creatine has elsewhere failed to benefit lung function at 5g daily for months relative to control[546] and failed to significantly attenuate the rate of lung function deterioration over 16 months at 10g daily[505] and 5g daily over nine months.[507]
In humans, studies that investigate links between serotonin and creatine supplementation find that 21 trained males, given creatine via 22.8g creatine monohydrate (20g creatine equivalent) with 35g glucose, relative to a placebo of 160g glucose, was found to reduce the perception of fatigue in hot endurance training, possibly secondary to serotonergic modulation, specifically attentuating the increase of serotonin seen with exercise (normally seen to hinder exercise capacity in the heat[233]) while possibly increasing dopaminergic activity (conversely seen to benefit activity in the heat[234]).[155]
Key point: Past a certain number of sets, the marginal increases in protein synthesis NO LONGER outweigh the cost of doing more sets. If 8 sets of chest exercises produce 95% of possible muscle protein synthesis… then it makes very little sense to do ANOTHER 10 sets (like most chest workouts) to try and inch out the final 5% of stimulation. Those extra 10 sets are simply damaging your muscle unnecessarily and impairing your ability to recover.
Higher percieved effort during heat (or due to elevations in body heat) are thought to be mediated by either the serotonergic system (suppresses performance)[388] or the dopaminergic system (enhances performance),[389][234] and creatine is thought to be involved in percieved effort during heat training since it has been noted previously to interact with neurotransmission by enhancing both serotonergic[253] and dopaminergic[230] neurotransmission.
Creatine is a hydrophilic polar molecule that consists of a negatively charged carboxyl group and a positively charged functional group [64]. The hydrophilic nature of creatine limits its bioavailability [65]. In an attempt to increase creatines bioavailability creatine has been esterified to reduce the hydrophilicity; this product is known as creatine ethyl ester. Manufacturers of creatine ethyl ester promote their product as being able to by-pass the creatine transporter due to improved sarcolemmal permeability toward creatine [65]. Spillane et al [65] analyzed the effects of a 5 days loading protocol (0.30 g/kg lean mass) followed by a 42 days maintenance phase (0.075 g/kg lean mass) of CM or ethyl ester both combined with a resistance training program in 30 novice males with no previous resistance training experience. The results of this study [65] showed that ethyl ester was not as effective as CM to enhance serum and muscle creatine stores. Furthermore creatine ethyl ester offered no additional benefit for improving body composition, muscle mass, strength, and power. This research did not support the claims of the creatine ethyl ester manufacturers.