Creatine electrolyte supplement improves anaerobic power and strength: a randomized double-blind control study

The body utilizes various energy systems to replenish adenosine triphosphate (ATP) during activity. One such energy system, the phosphagen system, is a fast-acting anaerobic energy system [1, 2]. Creatine phosphate is a naturally occurring molecule in the human body which replenishes ATP during rapid movements through the phosphagen system [3‐5]. It has been determined that increasing the storage of free creatine and creatine phosphate can help prolong the usage of the phosphagen system [1, 3, 6, 7]. Supplementation of creatine has been shown to enhance the total storage of creatine phosphate and helps increase anaerobic power and strength performances [3, 6, 8].

Creatine supplementation is used to enhance characteristics of physical performance, most commonly strength and power activities [9‐11]. Multiple groups have concluded that creatine supplementation, ranging from 1 week to 12 weeks, can be helpful in enhancing one-repetition maximum strength, total work capacity, increasing lean body mass, and, in some cases, increasing lower extremity power output primarily seen in cycling [9, 12, 13].

Electrolytes such as sodium, potassium, and magnesium are transporters used to aid in the absorption and utilization of creatine by the body [14, 15]. While some studies have combined the use of creatine supplementation with beta alanine and other solutions, there is very little literature on creatine supplementation coupled with electrolytes. Brilla et al. [15] examined the effects of a magnesium-creatine supplementation on body water and quadriceps torque. The group supplemented with Mg-creatine chelate displayed significant increases in their intra-cellular water, as well as quadriceps peak torque. Another study aimed to examine the impact of a supplement that consisted of creatine monohydrate (CM) with glucose, sodium, potassium, and taurine (CM + CHO). College aged male football players were tested for bench press strength, vertical jump height, and 100-yard dash times following an 8-week supplementation. Both interventions were compared to a group that only had the glucose and various electrolytes [16]. The CM + CHO groups showed significant increases in their bench press strength, vertical jump, and 100-yard dash times to the CHO only group, and larger relative increases compared to the CM only group [16]. Other authors have reported that creatine uptake is directly impacted by the presence of sodium, chloride, and calcium [17‐20]. Dai el al. found that when both calcium and magnesium were absent from an extracellular fluid, creatine uptake was significantly reduced by 47%. The same authors also found that in a similar fluid, creatine uptake is increased when concentrations of sodium and chloride are increased, even when creatine concentration remains constant [17]. For creatine transportation to occur, the body requires both sodium and chloride ions to transport the creatine molecules. Supplementing creatine with these electrolytes aids with increased uptake and storage of muscular creatine, thus potentially increasing performance.

The purpose of this study was to investigate the effects of a creatine supplement formulated with various electrolytes on upper and lower limb anaerobic power, and strength outcomes for college-aged individuals. We hypothesized that a six-week supplementation period of the multi-ingredient performance supplement (MIPS) would significantly increase predicted one-repetition maximum (1RM) for back squat and bench press. Additionally, we expected an increase in the amount of concentric work, mean power, peak power, mean rate of force development (MRFD), and peak force post MIPS supplementation for back squat and bench press during a maximal repetition test at 80% 1RM load.

A total of 22 participants completed both pre- and post-testing sessions separated by 6 weeks supplementation. Age, sex, height, and mass were all recorded at pre-test and post-test to describe the samples for both the placebo and MIPS groups (Table 1). The assumptions of normality and homogeneity of variances remained unviolated for the dependent variables. Greenhouse-Geisser corrections were taken into account when the assumption of sphericity was violated.

The initial one-way ANOVA displayed no significant differences between the placebo and MIPS groups at pre-test. Back squat 1RM (p = 0.54), bench press 1RM (p = 0.28), bench press concentric work (p = 0.72), mRFD (p = 0.08), mean power (p = 0.81), peak power (p = 0.50), peak force (p = 0.95) and back squat concentric work (p = 0.67), mRFD (p = 0.08), mean power (p = 0.72), peak power (p = 0.68), peak force (p = 0.73) where not significantly different at pre-test.

There was a significant interaction between time and group for back squat 1RM (p = 0.047, η_p² = 0.201) (Fig. 1). From pre- to post-testing, the MIPS group increased their back squat 1RM significantly by 13.4% (95% CI: 2.77, 23.8%) and the placebo group displayed a slight decrease of − 0.2% (95% CI: − 1.46, 2.87%). There was also a significant interaction between time and group for the bench press 1RM (p = 0.033, η_p² = 0.217) (Fig. 2). The MIPS group displayed a significant increase of 5.9% (95% CI: 2.5, 10.1%) while the placebo group increased by 0.7% (95% CI: − 3.49, 3.9%).

There were no significant interactions or main effects of time or group during the back squat maximal repetition test for any of the following: sum of concentric work (p = 0.229, 0.700, and 0.855, respectively), mRFD (p = 0.630, 0.653, and 0.215, respectively), mean power (p = 0.405, 0.884, and 0.897, respectively), peak power (p = 0.219, 0.064, 0.975, respectively), or peak force (p = 0.349, 0.097, 0.998, respectively).

There was a significant interaction between time and group for sum of concentric work during the bench press repetition test (p = 0.008, η_p² = 0.330). The MIPS group displayed an increased sum of concentric work of 26% (95% CI: 6.07, 46.87%) compared to a slight decrease of − 3.4% (95% CI: − 15.36, 8.63%) for the placebo group (Table 2). There was no significant interaction between time and group for mRFD (p = 0.101, η_p² = 0.142). There was a significant interaction between time and group for mean power (p = 0.003, η_p² = 0.402). The MIPS displayed an increased mean power of 17.9% (95% CI: 3.42, 32.46%) while the placebo displayed a decreased mean power of − 3.4% (95% CI: − 8.75, 2.09%) (Table 2). There was no significant interaction or main effect of time or group for peak force during the maximal bench press test (p = 0.355, 0.979, 0.955, respectively).

The purpose of the study was to examine the effects of a creatine electrolyte MIPS on strength and power in recreational strength trained individuals. We compared two supplementation groups, one was MIPS formulated with creatine and electrolytes and the other group had placebo formulated with only maltodextrin, before and after 6 weeks of supplementation. Measurements of maximal strength (1RM) as well as other biomechanical performance variables during the bench press and back squat. Our primary hypothesis was supported, the MIPS group displayed a significant increase to their back squat and bench press 1RM compared to the placebo group.

The MIPS group increased the maximal strength for both the back squat and bench press exercises following 6 weeks of supplementation. In agreement with this finding, Hoffman et al. [26] found an increase in back squat 1RM of approximately 15.6%, for groups supplemented with creatine monohydrate for 10 weeks using 10.5 g^.d^− 1. Pearson et al. [27] also found a significant increase in back squat 1RM following 10 weeks of creatine monohydrate supplementation. Subjects were given 5 g^.d^− 1 for the supplementation period and experienced a significant increase of 11.5% in their back squat 1RM [27]. Another study tested maximal back squat strength in female soccer players at five and 13 weeks of creatine monohydrate supplementation [2]. Supplementation consisted of a 15 g^.d^− 1 for one-week loading phase followed by a four-week maintenance phase of 5 g^.d^− 1. The soccer players displayed significant 23.6% increases in their 1RM back squat following 13 weeks of creatine supplementation [2]. These results are in line with the current data, which showed an increase of 13.4% in back squat strength following only a six-week MIPS intervention. The literature and current study seem to agree that creatine supplementation lasting at least 5 weeks can increase back squat maximal strength across various populations ranging from recreational to competitive athletes. Benefits from the MIPS were also very similar to those using creatine monohydrate at relatively similar doses (4–5 g^.d^− 1).

The current study displayed that subjects in the MIPS group significantly increased their bench press 1RM by 5.9% following 6 weeks of supplementation. Our results are in agreement with other studies that displayed significantly increased the upper body maximal strength in a range of active people following creatine supplementation [9, 22, 26, 28, 29]. Hoffman et al. [26] found an increase in bench press 1RM of 13%, for groups supplemented with creatine monohydrate for 10 weeks using 10.5 g^.d^− 1. This increase amounted to a two-and-a-half-fold increase compared to their placebo counterparts. Another study using 28 days of creatine supplementation found a 6% increase in bench press 1RM when compared to their baseline values [9]. Pearson et al. [27] used a 5 g^.d^− 1 creatine supplementation over 10 weeks and found that bench press maximal strength significantly increased by 3.4%. A recent study involving recreational bodybuilders used 5 g^.d^− 1 doses of creatine monohydrate and observed an increase in bench press 1RM over a four-week period by 7.5% [30].

Our secondary hypothesis was partially supported, as the MIPS group significantly increased their total concentric work and mean power during the bench press maximal repetition test. Very few studies using creatine supplementation have been done using the performance variables in the current study performing repetitions to failure under certain loading conditions [13, 21, 31]. A 28-day supplementation study using male powerlifters examined a carbohydrate-protein creatine supplements effect on maximal repetition tests across five subsequent sets of bench press [21]. Following supplementation, the groups supplementing with creatine had an increased number of repetitions in sets one, four, and five [21]. This finding could primarily be because of creatine supplementation increasing PCr, since the repetition test occurring at 80% 1RM is heavily dependent on the phosphagen system [13]. The phosphagen system is typically only predominant for 10–15 s and plays a large role in repeated bout exercises. An increase in the amount of creatine available can prolong the usage of the phosphagen system, thus increasing performance over the latter repetitions. The current study only used a single set at 80% of subject’s determined 1RM to closely examine the effect of MIPS supplementation on maximal repetitions to failure. A more recent study examined a similar protocol of performing repetitions to failure at 80% 1RM [13]. Following 30 days of supplementation, both groups supplemented with polyethylene glycosylated creatine (1.25 and 2.50 g^.d^− 1 doses) increased their repetitions to failure by 25.7 and 21.9%, respectively [13]. This result suggests that maybe a larger dose of creatine does not always indicate a greater benefit. The significant increase of 26.5% in the current study appears to be in line with current knowledge of creatine increasing the work capacity until failure while performing the bench press exercise at 80% 1RM.

The current data indicated a non-significant, but large effects size (η_p² = 0.16) increase in mRFD and a significant increase of mean power during the bench press maximal repetition test for the MIPS group. A maximal repetition test at this specified load is heavily dependent on the phosphagen system [21]. While no research was found on mRFD during the bench press, an increase of mRFD shows a possibility of decreased rate of fatigue. Subjects that displayed an increased mRFD were achieving their peak force at a much faster rate throughout their repetition test. Mean RFD has two major components that could be influenced due to fatigue: velocity and force [32]. With an increase in mRFD, it is possible that MIPS participants were able to maintain either their peak force applied to the barbell, as well as the rate at which the force was achieved. Both considerations are heavily influenced with fatigue, as fatigue takes effect, both the magnitude of force and speed of the movement should reduce. The results could indicate an increased performance during repetitions to failure, with the fatigue being minimized during the post intervention testing.

Most available information on creatine supplementation primarily involves an isolated creatine supplement. This current study combined both creatine and various electrolytes that potentially increase the absorption of creatine, increase transport into the muscle, and increase performance. Therefore, our results may not be directly relatable to a creatine only supplement, due to the addition of electrolytes in the current MIPS. However, Brilla et al. [15] supplemented participants using a magnesium-creatine supplement and observed increases in quadriceps peak torques along with increased intra-cellular water content. This finding could be potentially related to our current study displaying an increased back squat 1RM. The back-squat exercise is a quadriceps dominant movement, requiring greater knee extensor torques to overcome a greater amount of weight. Crisafulli et al. [33] examined a similar electrolyte creatine supplement on repeated sprints during cycling. Cycling performance (peak and average power output) during sprint cycling were increased following 6 weeks of an electrolyte creatine supplement. While not directly comparable, the current information merits further research on creatine supplemented that include electrolytes.

Six weeks of MIPS supplementation can be beneficial for increasing multiple facets of athletic performance in recreationally trained individuals. The MIPS increased both back squat and bench press maximal strength. Subsequently, the MIPS also displayed increases of concentric work and average mean power while performing a maximal repetition test of bench press at 80% 1RM load. This MIPS consisting of creatine and electrolytes could be beneficial for people wishing to increase their performance. Additional studies are needed to compare the MIPS to a creatine only supplement to examine if the performance increase is directly related to the electrolytes in the MIPS.