Twenty-one healthy, resistance-trained, male subjects (27.2 ± 5.6y; 173.5 ± 5.7 cm; 82.8 ± 12.0 kg) completed the current investigation. Thirty-three subjects were recruited, and 3 subjects did not complete the study due to scheduling conflicts, 3 were not compliant with protocols, and 2 sustained injuries during the study unrelated to training or supplementation. Each subject was required to be capable of lifting 1.5 times their bodyweight in the squat and deadlift and 1 times bodyweight in the bench press. At baseline, the placebo (PLA) group was able to squat 1.71 ± 0.21, bench press 1.45 ± 0.19, and deadlift 2.17 ± 0.25 times their bodyweight, and the treatment (TRT) group was able to squat 1.58 ± 0.20, bench press 1.33 ± 0.20, and deadlift 1.97 ± 0.26 times their bodyweight. Approval for research with human subjects was obtained from the MusclePharm Sports Science Institute IRB, and subjects provided written informed consent documents prior to participation in the study.
The precise methods of the present study have previously been published with the exception of a difference in treatment . Subjects were randomly assigned to either the PLA (n = 11) or TRT (n = 10) groups. They were instructed to consume 1 serving (2 mL) of either PLA or TRT (150 mg ElevATP™, FutureCeuticals Inc., Momence, IL; 180 mg blend of caffeine anhydrous and PurEnergy™, Chromadex Inc., Irvine, CA; and 38 mg B vitamins) 45 min prior to training on training days or at a similar time of day on rest days. For a detailed composition of ElevATP™, composed of ancient peat and apple extracts, see . The PurEnergy™ ingredient is composed of 43 % caffeine and 57 % pterostilbene. Total caffeine content per serving was ~129 mg. Supplement vials were weighed to ensure compliance. Subjects were resistance trained under the guidance of a certified strength and conditioning specialist 3 days per week for 8 weeks followed by a 2-week overreach and 2-week taper phase corresponding to weeks 9–10 and 11–12, respectively. A eucaloric diet consisting of 50 % calories from carbohydrates, 25 % from protein, and 25 % from fat was prescribed to all subjects at the onset of the study, and diets were tracked weekly via 3-day food logs. Total calories were determined for each individual based on the Mifflin St. Jeor equation adjusted for activity level. Subjects were measured at weeks 0, 4, 8, 10, and 12 for all body composition variables. Blood draws and vital sign measurements were conducted at weeks 0, 8, and 12. Body composition variables collected consisted of DEXA, which determined lean soft tissue (LST), fat mass (FM), and body fat percentage (% Fat), and ultrasound, which determined cross-sectional area (CSA), muscle thickness (MT), and fat thickness (FT).
Resistance training program
Weeks 1–8 consisted of one muscle hypertrophy-oriented workout, one power workout, and one strength-oriented workout each week. The hypertrophy session consisted of barbell back squat, bench press, deadlift, incline bench press, hammer strength power squat machine, hammer strength isolateral bench press, leg press, leg extension, leg curl, and triceps extension performed for 3 sets of 6–12 repetition at 60-80 % 1RM intensity. The power session consisted of barbell back squat, bench press, and deadlift exercises performed for 5 sets of 2–5 repetitions with a goal of high velocity of movement with 40-60 % 1RM intensity. After performing the main exercises on the power day, subjects performed bent over row, pulldown, dumbbell row, shoulder press, lateral raise, and bicep curl exercises for the goal of muscle hypertrophy as described for chest and leg exercises. The strength session consisted of barbell back squat, bench press, deadlift, shoulder press, and pulldown exercises performed for 3 sets of 1–5 repetitions at 85–100 % 1RM intentisty. Following the resistance exercises on the strength day, participants performed 2–6 sets of 10–30s Wingates on a cycle ergometer with 2–4 min rest. Participants rested 48–72 h between each training day, and 30–120 s between sets on the hypertrophy day or 2-5 min between sets on the power and strength days. All exercises were completed within 60–120 min. During the overreach phase, participants performed high-volume workouts, similar to the hypertrophy-oriented workouts performed during weeks 1–8, on Monday through Thursday, with a strength-oriented workout or performance testing conducted on Friday for weeks 9 and 10, respectively. The taper weeks consisted of one power session on Mondays. On Wednesdays and Fridays, participants performed 1–3 heavy sets for 2–5 repetitions of the back squat, bench press, and deadlift, and each heavy exercise was immediately followed by the same exercise for 3 power-oriented sets, as previously described, before progressing to the next exercise.
Urine specific gravity was determined on each body composition testing day to ensure measurements were conducted in a euhydrated state. On 3 occasions, a participant was required to drink water until another urine sample could be submitted and verified for adequate hydration status. Body weight was determined using a calibrated column scale (SECA, Chino, CA). Body composition was analyzed for whole-body and segmental LST, FM, and % Fat using DEXA (Lunar Prodigy Primo, General Electric, Fairfield, CN) with enCORE software (Version 15, Madison, WN). Test-retest reliability for DEXA LST, % Fat, and FM, as measured using 15 subjects, resulted in an average ICC of >0.99. CSA, MT, and FT were determined using ultrasound (Logiq e, General Electric, Fairfield, CN). The minimum differences  needed to be considered a true change are 0.107 cm2 and 0.038 cm for CSA and MT, respectively. Ultrasonography determined CSA was measured at 75 % femur length, as defined as the distance from the anterior superior iliac spine to the superior aspect of the patella. MT of the quadriceps was measured at 50 % femur length, defined as the distance from the greater trochanter of the femur to the lateral epicondyle of the femur. MT was defined as the combined thickness of the vastus lateralis and vastus intermedius. The distance from the superficial aspect the femur to the deep aspect of the superficial fascia of the vastus lateralis was measured. FT was measured at the same site as MT, and it was defined as the distance from the superficial aspect of the vastus lateralis fascial layer to the deep aspect of the hypodermis. For MT, FT, and CSA, ICC was 0.99, 0.99, and 0.97, respectively. Vital signs were determined using an automated, digital sphygmomanometer (Omron Corporation, Kyoto, Japan). Blood draws were performed via venipuncture by a trained phlebotomist. Following a 10-h fast, all subjects submitted a blood sample for analysis in the morning to control for diurnal variations. Blood variables consisted of white blood cell count (WBC), red blood cell count (RBC), hemoglobin, hematocrit, mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), red blood cell distribution width (RDW), platelets (absolute), neutrophils (percent and absolute), lymphocytes (percent and absolute), monocytes (percent and absolute), eosinophils (percent and absolute), basophils (percent and absolute), serum glucose, blood urea nitrogen (BUN), creatinine, estimated glomerular filtration rate (eGFR), BUN:creatinine, sodium, potassium, chloride, carbon dioxide, calcium, protein, albumin, globulin, albumin:globulin (A/G), bilirubin, alkaline phosphatase, aspartate aminotransferase (AST), alanine aminotransferase (ALT), total cholesterol, triglycerides, high density lipoprotein (HDL) cholesterol, very low density lipoprotein (VLDL), and low density lipoprotein (LDL) cholesterol. Blood variables were analyzed by a third party (Laboratory Corporation of America, Denver, CO). Inter-test reliability results from 12 men and women measured up to one week apart at the aforementioned laboratory resulted in no significant differences from day-to-day (p > 0.05) and an average inter-test Coefficient of Variation of 6.9 % for all tests.
Repeated measures ANOVAs were performed to assess group, time, and group by time interactions with a significant p-value considered as ≤0.05. A Bonferroni post-hoc analysis was used to locate differences. Independent T-tests were conducted on the delta values for each time point. Dependent T-tests were conducted to determine within group differences for all body composition and hematology data with a significant interaction. Statistica (Version 10, Statsoft, Tulsa, OK) was used for all statistical analyses.