The objective of this study was to determine the efficacy of pre- and post-RT supplementation with MIPS on body composition, muscle strength, and power in resistance-trained men participating in a six-week periodized RT program. With this specific population, any gains in strength should be almost entirely due to physiological and hypertrophic changes to the trained muscles, rather than improvements in neuromuscular coordination. Shelmadine et al. [14
] noted large increases in markers of satellite cell activation and hypertrophy, and modest increases in LM (4.8%) for their MIPS group after only four weeks in untrained men. By increasing the time course and total volume of training in the present study, we aimed to augment the opportunity for muscle growth. In addition to ingesting SHOT before exercise, our participants also consumed one serving of SYNTH immediately post-exercise and on every non-training day. This supplementation model, similar to that used by Spillane et al. [21
], provided a better environment for muscle hypertrophy and recovery and supplement loading than the modality used by Shelmadine et al. [14
]. Both Shelmadine et al. and Spillane et al. [14
] allowed participants to train independently, while the present study monitored all training sessions with experienced research staff that provided form corrections and spots for free-weight lifts. The emphasis placed on consistent lifting form in this study, coupled with researcher supervision, helped ensure full participant compliance with training as well as reduced variability due to inter-subject differences or deficiencies in form.
Changes observed in body composition were perhaps the most remarkable results of the current study. MIPS increased LM by 4.7%, a degree similar to those observed in untrained males by Spillane et al. (3.5%) and Shelmadine et al. (4.8%) [14
] and greater than that observed in trained males by Schmitz et al. (2.4%) [22
]. Because there were no changes in FM, the decreased %BF observed in the MIPS group was due to increased LM and overall body mass. The PLA group made no significant changes in any body composition variable, although there were trends for improved LM. The lack of change in FM demonstrated in this study reflects the findings of other similar studies [13
], but is at odds with popular claims made about these products. One of the proprietary blends listed on the SHOT label contains 376 mg of a combination of caffeine, β-phenylethlylamine HCL, hordeum vulgare
bud, and L-tyrosine, and is marketed in SHOT and in other similar products as a “fat burning” component. However, because participants were instructed to consume their normal dietary intake rather than being fed specific meals with specific caloric restrictions, we cannot draw the conclusion that SHOT and SYNTH consumption pre- and post-exercise are ineffective at reducing FM. However, it is worth noting that no changes in dietary intake were reported from baseline (week 0) to post-testing (week 6) in a subset (n
8) of our participants, therefore, our lack of change in body mass (kg) is likely real. Perhaps more valuable to consumers, limb circumferences increased only in thigh measurements for the MIPS group, but not for the PLA group.
A significant increase in LM was measured in the MIPS group but not in the PLA group. This is in concurrence with many similar studies [13
]. As muscle mass is one of the main determinants of strength and power [32
], it is somewhat unexpected that the MIPS group did not experience greater improvements in 1RM strength, although 1RM tests may not be sensitive enough to detect the modest difference in LM improvement exhibited by the MIPS group by these trained men. Likewise, this most likely explains the lack of group x time effects in circumference measurements other than thigh. One remarkable finding of this study is that the increase noted in LM by the MIPS group in this study (+4.7%) was very similar to that of the supplement group in Shelmadine et al. (+4.7%) [14
], despite the increased training status of our participants.
While the present study noted a main time effect for peak and average anaerobic power and total work performed, there were no differences between the two groups. There was, however, a strong trend (group × time effect, p
0.06) for the MIPS group to improve peak anaerobic power. We also noted an increase in mean anaerobic power for MIPS, but not for PLA (Figure ). These findings are similar to those of Beck et al. [13
], who demonstrated significant increases in peak and mean anaerobic power following 10 weeks of RT using untrained males consuming a pre-exercise supplement containing protein, creatine, and BCAAs. The protocol used by Beck et al. called for two consecutive 30-second cycling bouts, whereas the present study only used a single bout. The differences in training duration (six weeks vs. 10 weeks), number of cycling bouts, and training status may explain why Beck et al. were able to elicit significant group x training effects while we were not.
We observed a significant (p
0.035) time effect for resting serum testosterone to increase with chronic training, but no group x time effects were observed. This is in contrast to a study by Rankin et al. [33
] which demonstrated decreases in testosterone following nine weeks of RT and supplement consumption, but in agreement with other studies linking whole body RT programs with enhanced testosterone. Coryceps sinesis, an ingredient included in the MIPS utilized for this study, is purported by supplement manufacturers to enhance testosterone levels in males. Based on our findings and those of Hsu et al. [34
] who specifically looked at the effect of coryceps sinesis on testosterone in conjunction with RT, we conclude that MIPS and coryceps sinesis did not enhance resting testosterone concentrations in response to chronic exercise in the present study. In addition, in the present study no changes for either group were noted in IGF-1 or hGH. Shelmadine et al. [14
] and Spillane et al. [21
] reported a time effect for IGF-1, but did not observe group x time effects. With the similarity in supplementation and training protocols between Spillane et al. [21
] and ours, differences in training status may explain why our participants did not exhibit detectable changes in IGF-1. Neither Shelmadine et al. [14
] nor Spillane et al. [21
] investigated changes in testosterone or hGH. Our observation of no change in hGH with RT is in agreement with Kraemer et al. [35
], who measured basal hGH following three, six, and eight weeks of resistance training in untrained males. It is possible that due to the training status of these men, changes in these anabolic hormones may have been blunted.
It was also expected that the inclusion of beta alanine in MIPS would yield improvements in fatigue index through the lactate buffering effects of carnosine. Instead, we found no significant time or group × time effect for fatigue index, in contrast to the findings of others [5
]. Hoffman et al. noted improvements in fatigue index following 30 days of beta alanine supplementation in American football players during offseason training [5
]. Some of this discrepancy may be explained by beta alanine dosages. In studies that have demonstrated improvements in performance, beta alanine dosages tend to range from 4.8 to 6.0 g·day-1
]. Unfortunately, the MIPS in the present study included beta alanine as part of a proprietary blend, rather than labeling it independently and, therefore, we do not know the true concentration of beta alanine in the product. We can only speculate, therefore, that our MIPS group may have been consuming less than the 4.8 g/day that has been shown to elicit training enhancements.
The present study demonstrated a significant effect of time for both CP and LP strength in both groups; however, there was no group x time effect. Shelmadine et al. [14
] also noted a training effect for both groups in CP and LP following 28 days of RT with SHOT supplementation before RT for 28 days. They noted that the SHOT supplemented group improved CP significantly more than the placebo group (18.4% vs. 8.8%, respectively, p
]. In contrast to Shelmadine et al., Beck et al. [13
] reported no differences in training-induced enhancements in CP or LP between a creatine-protein supplement group and placebo groups in their 10-week RT study [13
]. Cribb et al. were able to elicit 1RM group × time effects in trained males following 10 weeks of RT and consumption of whey protein [40
] or whey protein and creatine [41
]. With so much conflicting evidence and confounding variables, it is difficult to draw conclusions about the effectiveness of MIPS on 1RM strength in trained males. It is worth noting, however, that in all of these studies the supplement group increased LM significantly more than the placebo.
Isokinetic leg exercise results were mixed. There appeared to be a pattern for both groups to improve strength and power during flexion but to make little improvement or even decrease performance in extension, as was the case with 30°sec-1
extension in the MIPS group. However, the MIPS group did exhibit trends (p
0.054) for improvements in some 60°sec-1
extension variables. Training specificity is one explanation for these data; our training program included seated hamstring curls, but not knee extensions. Thus, each participant spent six weeks without doing seated extension types of exercise (they participated in leg press and lunge exercises instead). Little investigation has been conducted into the effect of MIPS and RT on isokinetic strength. These results are surprising as single-supplement [29
] and training-alone [45
] studies have demonstrated modest increases in isokinetic performance following RT.
Results of the isometric tests are particularly puzzling, as the MIPS group made no improvements while the PLA group improved in several measures during flexion. This is in contrast to other studies using supplement combined with training [47
] and correlations of muscle mass and isometric force production [32
]. There are a few possible explanations for these findings. Neither group in the present study performed isometric exercise as part of training. Thus, training specificity may have played a role in the lack of findings; however, this would have applied to both groups equally. Moreover, isometric exercise performance is somewhat sensitive to innate muscle fiber type distribution [49
], which was not tested or controlled for in this investigation.
We observed no differences in volume (weight lifted × repetitions x sets) lifted for any exercise over the course of the training period. This was in contrast to common findings of other supplement plus training studies involving caffeine [12
], beta alanine [5
], and creatine [9
], but not all studies [4
]. The lack of difference between groups in training volume may have been a result of our study design rather than supplement effects. All participants were instructed that the goal of every set should be failure and they were to achieve this by selecting weights that caused them to fail at a specific number of repetitions (10 for weeks one and two, six for weeks three and four, and four for weeks five and six). The number of repetitions was controlled in order to facilitate the periodized training goals. If participants lifted to failure on every set, differences in training volume may have been evident. On the other hand, eliminating training volume as a variable leaves manipulation of hypertrophic pathways by the supplement ingredients as the most probable explanation for increased LM in MIPS but not for PLA. In addition, all of the participants had performed the required exercises in past workouts prior to beginning the study. The participants were also familiar with overloading the muscles with periodized training. However, we did not survey or record the degree to which the study routine was similar to or different from the participant’s regular workout program.