Neurons are unable to synthesize choline and rely on dietary intake to insure sufficient acetylcholine production [2]. Acetylcholine is critical for many physiological functions and any deficiency could result in a multitude of physiological problems. One of the more interesting findings has been the benefit that choline supplementation has had on memory and cognition improvements [3-6]. The importance of enhancing neurotransmitter function has interesting implications for athletic performance. Exercise that reduces plasma choline concentrations (i.e. marathon running) has been suggested to benefit from choline supplementation [7,8]. However, support for this hypothesis has been lacking [9,10]. This may be related to the inability of prolonged exercise to deplete plasma choline concentrations to levels that result in performance decrements [9,10]. However, if choline can improve neurotransmitter concentration then it stands to reason that it may have a potential ergogenic role in athletic events that involve power performance and the ability to react to external stimuli, even during events that plasma choline concentrations are normal. Choline, provided as phosphatidylcholine, is 12-fold more effective than inorganic choline salts in increasing serum concentrations and maintaining elevated concentrations for a longer duration (12 hours versus 30 minutes) [11,12]. Thus, most supplement studies will provide choline as phosphatidylcholine or L-Alpha Glycerylphosphorylcholine (alpha-GPC), a water-soluble form lacking the hydrophobic tail groups. In addition to being an excellent source of choline, acute alpha-GPC supplementation has been shown to augment growth hormone response to resistance exercise [13].

Phosphatidylserine is also a phospholipid that is incorporated into the membrane of organs with high metabolic activity such as brain, heart, lung, liver and skeletal muscle [14,15]. Several studies have demonstrated that phosphatidylserine may reduce inflammation ([16,17] and act as an antioxidant [18,19]. These properties have led to additional investigations on the ability of phosphatidylserine to enhance recovery from exercise. A 750 mg dosing of phosphatidylserine for 7 days prior to an acute bout of exhaustive exercise resulted in significant improvements in sprint performance [20] and an increase in time to exhaustion during intermittent cycling exercise [21]. Starks and colleagues [15] reported a lowered stress response to moderate intensity cycling exercise (65% - 85% VO₂max) following 10 days of supplemention with 600 mg of phosphatidylserine, reflected by a reduced cortisol response to exercise. However, Kingsley and colleagues [22] were unable to support an improved recovery in individuals performing an acute bout of eccentric exercise (downhill running).

Subjective feelings of energy, fatigue, focus and alertness measured via a VAS are depicted in Figure ​Figure3,3, Figure ​Figure4,4, Figure ​Figure55 and Figure ​Figure6,6, respectively. Significant declines in subjective feelings of energy were observed between PRE and POST for both groups at T1 and T2. No significant differences in subjective measures of energy were seen between the groups at any time point. Elevations in subjective feelings of fatigue were seen for CRAM at both T1 (p = 0.001) and T2 (p = 0.000), but significant elevations in fatigue were seen at T2 (p = 0.029) only for PL. No differences were noted in fatigue levels between CRAM and PL groups at any time point. Subjects in the CRAM group were able to maintain their focus between PRE and POST during both T1 (p = 0.152) and T2 (p = 0.082) trials, whereas significant declines in focus were observed between PRE and POST in the PL group at T1 (p = 0.037) and T2 (p = 0.014). However, no differences in focus were seen between the groups at any time point. No differences between PRE and POST for subjective feelings of alertness were seen in the CRAM group at T1 (p = 0.83), but a significant decline in alertness was recorded at T2 (p = 0.040). Lower subjective levels of alertness were recorded at POST for T1 (p = 0.005) and T2 (p = 0.033) for the PL group. No differences in alertness though were seen between the groups at any time point.

Previous investigators have suggested that choline supplementation may provide an ergogenic benefit during prolonged or exhaustive exercise [1,7,8]. This has been based primarily on the assumption that exhaustive exercise may lower acetylcholine concentrations resulting in fatigue and lowered exercise performance. The basis of choline supplementation is that free choline can increase the rate of acetylcholine synthesis [24,25]. If acetylcholine levels become reduced during exhaustive exercise, supplementing with choline may maintain neurotransmitter concentrations and reduce fatigue and maintain performance. However, Spector and colleagues [26] reported that exercising until exhaustion at 70% of VO₂max did not deplete choline. This is consistent with other studies reporting that choline concentrations may not be depleted during prolonged exercise [9,10], but contrasts with other studies showing reduced plasma choline concentrations during prolonged exercise [7,27,28]. Differences between these studies are difficult to explain considering that endurance exercise was the mode examined in these investigations, and subject populations were both recreationally and competitively-trained individuals. More consistent findings have been reported in choline's ability to enhance cognition and memory [5,7,29]. However, reports of enhanced memory or cognition following choline supplementation following a physical stress are limited. Only one study examined choline's potential to enhance cognitive performance following a physical stress, and results did not prove to be efficacious [9]. To date, it appears that the benefit of choline supplementation is inconclusive.

In contrast to the majority of research on choline ingestion, the present study incorporated relatively short-duration, high intensity anaerobic exercise protocol to elicit fatigue. Furthermore, the supplement ingested contained smaller concentrations of choline than has been previously shown to be efficacious. Despite these differences, the combination of other dietary ingredients appeared to have provided a positive effect on performance and subjective feelings of fatigue and alertness. To maximize the effectiveness of a supplement many sport nutrition companies combine several ingredients to provide a synergistic effect. The CRAM supplement combined choline (as α-glycerophosphocholine and choline bitartrate) with phosphatidylserine, carnitine, an energy matrix (caffeine and tyrosine) and vitamins. Phosphatidylserine has been previously shown to enhance recovery following high- and moderate-intensity exercise [1,15,20-22]. In addition, phosphatidylserine has been shown to enhance subjective feelings of energy, elation and confidence in healthy students subjected to stressful mental tasks [30] and in combination with carbohydrates to improve performance in golfers during induced stress [31]. Carnitine supplementation has been shown to enhance recovery following high intensity exercise [32,33], as reflected by reduced markers of muscle damage and a greater anabolic response (elevation in IGF binding protein) to exercise recovery. Although the vitamins included in CRAM are not known to be ergogenic when no deficiencies are present, the energy matrix found in this supplement has been shown to be effective in delaying time to fatigue and increasing volume of training [34].

The ability to maintain reaction performance following fatigue may have been due to the combined effect of choline, phosphatidylserine and the energy matrix. Although this is the first investigation to examine this combination of ingredients following exhaustive anaerobic exercise, previous studies have shown that this combination of ingredients to be effective in augmenting exercise [35] and cognitive [36] performance in rodents. Although the mechanism of action has not been fully elucidated, it has been suggested that this combination of ingredients may contribute to an enhanced neuroprotective effect via a stronger defense of membrane integrity [36]. Glycerophosphocholine and phosphatidylserine have been shown to form membrane phospholipids [37], and acetyl-L-carnitine may provide neuroprotective effects by buffering oxidative stress and maintaining energy supply to neurons [38]. The concentrations of ingredients used in CRAM appear to have been sufficient to maintain performance during T1; however, did not appear to provide the same effect at T2. This may have been due to habituation in that the daily concentration of ingredients ingested may not have provided the same physiological effect following 4 weeks of supplementation. Another potential explanation is that the weekly familiarization sessions that continued throughout the experimental period may have provided a training effect thereby making it more difficult for CRAM to affect performance at the same concentrations. However, the use of weekly familiarization sessions was critical to our study design to limit potential detraining effects. Thus, future research should address the role of chronic CRAM supplementation on acute exercise performance.