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The Addition of Beta-hydroxy-beta-methylbutyrate and Isomaltulose to Whey Protein Improves Recovery from Highly Demanding Resistance Exercise a
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William J. Kraemer PhD FACN , David R. Hooper MA , Tunde K. Szivak MA , Brian R. Kupchak b
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PhD , Courtenay Dunn-Lewis PhD , Brett A. Comstock PhD , Shawn D. Flanagan MA MHA , b
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David P. Looney MS , Adam J. Sterczala MS , William H. DuPont MS , J. Luke Pryor MS , Hiub
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Ying Luk MS , Jesse Maladoungdock MS , Danielle McDermott MS , Jeff S. Volek PhD RD & a
Carl M. Maresh PhD a
Department of Human Sciences, The Ohio State University, Columbus, Ohio
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Human Performance Laboratory, Department of Kinesiology, Storrs, Connecticut Published online: 11 Mar 2015.
To cite this article: William J. Kraemer PhD FACN, David R. Hooper MA, Tunde K. Szivak MA, Brian R. Kupchak PhD, Courtenay Dunn-Lewis PhD, Brett A. Comstock PhD, Shawn D. Flanagan MA MHA, David P. Looney MS, Adam J. Sterczala MS, William H. DuPont MS, J. Luke Pryor MS, Hiu-Ying Luk MS, Jesse Maladoungdock MS, Danielle McDermott MS, Jeff S. Volek PhD RD & Carl M. Maresh PhD (2015) The Addition of Beta-hydroxy-beta-methylbutyrate and Isomaltulose to Whey Protein Improves Recovery from Highly Demanding Resistance Exercise, Journal of the American College of Nutrition, 34:2, 91-99, DOI: 10.1080/07315724.2014.938790 To link to this article: http://dx.doi.org/10.1080/07315724.2014.938790
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Original Research
The Addition of Beta-hydroxy-beta-methylbutyrate and Isomaltulose to Whey Protein Improves Recovery from Highly Demanding Resistance Exercise
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William J. Kraemer, PhD, David R. Hooper, MA, Tunde K. Szivak, MA, Brian R. Kupchak, PhD, Courtenay Dunn-Lewis, PhD, Brett A. Comstock, PhD, Shawn D. Flanagan, MA, MHA, David P. Looney, MS, Adam J. Sterczala, MS, William H. DuPont, MS, J. Luke Pryor, MS, Hiu-Ying Luk, MS, Jesse Maladoungdock, MS, Danielle McDermott, MS, Jeff S. Volek, PhD, RD, Carl M. Maresh, PhD Department of Human Sciences, The Ohio State University, Columbus, Ohio (W.J.K, D.R.H., T.K.S., S.D.F., W.H.D., J.S.V., C.M.M.); Human Performance Laboratory, Department of Kinesiology, University of Connecticut, Storrs, Connecticut (B.R.K., C.D.-L., B.A.C., D.P.L., A.J.S., J.L.P., H.-Y.L., J.M., D.M.) Key words: resistance training, HMB, whey protein, carbohydrate, muscle damage, exercise Objective: This study evaluated whether a combination of whey protein (WP), calcium beta-hydroxy-betamethylbutyrate (HMB), and carbohydrate exert additive effects on recovery from highly demanding resistance exercise. Methods: Thirteen resistance-trained men (age: 22.6 § 3.9 years; height: 175.3 § 12.2 cm; weight: 86.2 § 9.8 kg) completed a double-blinded, counterbalanced, within-group study. Subjects ingested EAS Recovery Protein (RP; EAS Sports Nutrition/Abbott Laboratories, Columbus, OH) or WP twice daily for 2 weeks prior to, during, and for 2 days following 3 consecutive days of intense resistance exercise. The workout sequence included heavy resistance exercise (day 1) and metabolic resistance exercise (days 2 and 3). The subjects performed no physical activity during day 4 (C24 hours) and day 5 (C48 hours), where recovery testing was performed. Before, during, and following the 3 workouts, treatment outcomes were evaluated using blood-based muscle damage markers and hormones, perceptual measures of muscle soreness, and countermovement jump performance. Results: Creatine kinase was lower for the RP treatment on day 2 (RP: 166.9 § 56.4 vs WP: 307.1 § 125.2 IU ¢ L¡1, p 0.05), day 4 (RP: 232.5 § 67.4 vs WP: 432.6 § 223.3 IU ¢ L¡1, p 0.05), and day 5 (RP: 176.1 § 38.7 vs 264.5 § 120.9 IU ¢ L¡1, p 0.05). Interleukin-6 was lower for the RP treatment on day 4 (RP: 1.2 § 0.2 vs WP: 1.6 § 0.6 pg ¢ ml¡1, p 0.05) and day 5 (RP: 1.1 § 0.2 vs WP: 1.6 § 0.4 pg ¢ ml¡1, p 0.05). Muscle soreness was lower for RP treatment on day 4 (RP: 2.0 § 0.7 vs WP: 2.8 § 1.1 cm, p 0.05). Vertical jump power was higher for the RP treatment on day 4 (RP: 5983.2 § 624 vs WP 5303.9 § 641.7 W, p 0.05) and day 5 (RP: 5792.5 § 595.4 vs WP: 5200.4 § 501 W, p 0.05). Conclusions: Our findings suggest that during times of intense conditioning, the recovery benefits of WP are enhanced with the addition of HMB and a slow-release carbohydrate. We observed reductions in markers of muscle damage and improved athletic performance.
INTRODUCTION
support [1,2]. Further, athletes may fail to balance training and recovery as they strive for maximal performance [3]. When excessive stress is placed on the body’s recovery process, which can no longer compensate, reductions in strength, overtraining syndrome [3], and possibly even injury (such as rhabdomyolysis) may occur. Various dietary supplements have been
In order to maximize adaptations to resistance exercise, progressive increases in training loads and frequency are typically recommended, along with the use of periodization [1]. Rigorous conditioning sequences may require additional nutritional
Address correspondence to: William J. Kraemer, PhD, FACN, Department of Human Sciences, The Ohio State University, A054 PAES Bldg, 305 West 17th Ave, Columbus, OH 43210. E-mail: [email protected] Abbreviations: WP D whey protein, RP D recovery protein, HMB D beta-hydroxy-beta-methylbutyrate
Journal of the American College of Nutrition, Vol. 34, No. 2, 91–99 (2015) Ó American College of Nutrition Published by Taylor & Francis Group, LLC 91
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Additive Effects of HMB and Isomaltulose developed to support the recovery process by reducing muscle damage and the loss of physical performance. Protein supplementation is a prominent example: though resistance training has been shown to increase protein synthesis [4], net protein balance may remain negative without the use of a protein supplement afteracute resistance exercise [5]. Different types of protein have been studied, including proteins from different sources (e.g., whey and soy based). In a recent study, we directly compared 2 sources of protein and demonstrated that despite isocaloric and isonitrogenous conditions, lean body mass gains were greater in subjects who supplemented with whey [6]. The mechanism for this preferential response to whey protein may reflect increased branched-chain amino acid content, and leucine in particular, because these amino acids activate key protein synthesis enzymes after physical exercise [7]. This theory was echoed in a recent review, where it was suggested that leucine may be responsible for the efficacy of protein supplements, as opposed to brain chain amino acids (BCAAs) generally [8]. A possible explanation for the superiority of leucine over other amino acids lies in its metabolite, beta-hydroxy-beta-methylbutyrate (HMB), produced from the reversible transamination of leucine to a-ketoisocaproate (KIC) [9], followed by production of HMB in the cytosol. KIC can also be metabolized in the mitochondria [10], yet both pathways lead to the production of hydroxymethylglutaryl-coenzyme A (HMG-CoA), a precursor for cholesterol synthesis. The current model for HMB in recovery is that damaged muscle cells are unable to produce enough HMG-CoA (and therefore cholesterol) to function properly [10]. As a result, HMB supplementation may stabilize cellular membranes, allowing for maximal cell growth [11]. The ability of HMB to stabilize membranes is supported by its ability to reduce circulating creatine kinase (CK), an intracellular enzyme thought to increase with cell membrane permeability as a result of skeletal muscle damage [12]. The ability of HMB to aid the recovery process following resistance training could thus play an important role, because it has been suggested that CK should return to normal in order to avoid overtraining or muscular pathology [13]. Accordingly, with 3 weekly days of resistance training, Nissen et al. [14] demonstrated significantly lower plasma CK in subjects who consumed HMB compared to a control group. These results were duplicated in more recent work, which showed that HMB supplementation is accompanied by significant reductions in CK with one session or 12 weeks of resistance training [15,16]. Additional proposed mechanisms for the role of HMB in strength improvement are focused on HMB’s ability to improve net protein balance by altering anabolic, catabolic, and inflammatory factors [10]. Until recently, studies in this area had predominantly utilized cell cultures or animal models. However, Wilkinson et al. [17] confirmed elevated muscle protein synthesis as well as attenuated muscle protein breakdown with HMB and leucine supplementation in vivo. Furthermore, it was recently demonstrated that HMB
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could reduce circulating tumor necrosis factor-a (TNF-a) and monocyte TNF-a receptor 1 expression after intense exercise, indicating that HMB may positively alter the immune response to exercise [18]. In addition to whey protein (WP) and HMB, carbohydrate supplementation also appears to have beneficial effects on recovery, which may stem from actions on circulating cytokines, including interleukin-6 (IL-6). These messenger molecules are released from muscle and various lymphocytes and are associated with altered metabolic activity, which may in turn promote inflammatory immune activity [19]. For example, elevations in IL-6 are associated with glycogen depletion [20], and carbohydrate supplementation can attenuate this response following long-distance running [21]. Though glycogen depletion is typically associated with endurance activities, resistance training can also challenge glycolysis, especially when short rest intervals are used. To that end, elevations in IL-6 have been observed from immediately post to upwards of an hour after resistance exercise [22], as well as up to 72 hours later [23]. Such prolonged increases in IL-6 would be of concern to individuals engaging in extreme conditioning protocols, where high training frequencies are also typically employed (5–6 times per week). In such cases, resistance training with high glycolytic demands performed at high frequencies could result in chronically elevated resting IL-6 concentrations, which may have detrimental effects on metabolism and inflammation [24]. As a result, recovery from repeated resistance training workouts, especially those that demand more glycolytic metabolism, might be aided by supplementation with carbohydrates and especially those metabolized more slowly, such as isomaltulose. Despite the profound benefits of resistance training on health and performance, in certain circumstances, excessive demands can be placed on the recovery process. Though WP has been shown to be an effective supplement, resistance training protocols with high volume, frequency, and glycolytic demands may place greater stress on recovery than the traditional workouts that have been used to study WP. Therefore, the purpose of this study was to compare recovery from highly demanding resistance exercise with WP or a supplement containing whey, HMB, and a slow-release carbohydrate (isomaltulose).
MATERIALS AND METHODS This investigation examined EAS Recovery Protein (RP; EAS Sports Nutrition/Abbott Laboratories, Columbus, OH), a nutritional supplement containing calcium beta-hydroxy-betamethylbutyrate (HMB), isomaltulose, and whey protein. A double-blind, counterbalanced within-group design was used to evaluate whether RP was able to offset indirect markers of tissue disruption caused by intense resistance exercise better than WP alone (see Fig. 1). The recovery process was assessed using blood markers of muscle damage (CK), blood hormone
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Additive Effects of HMB and Isomaltulose
Fig. 1. Study design: (A) visit sequence and (B) timeline of the acute testing protocol.
concentrations of potential therapeutic targets, perception of muscle soreness, and countermovement jump performance.
Subjects Thirteen men (age: 22.6 § 3.9 years; height: 175.3 § 12.2 cm; weight: 86.2 § 9.8 kg) with at least one year of resistance training experience volunteered to participate in the study. Height was measured using a stadiometer (Seca, Hamburg, Germany). Weight was measured using a calibrated scale (OHAUS Corp., Florham Park, NJ). All subjects were fully informed of the protocol design and associated risks of this investigation before signing an informed consent approved by the University of Connecticut Institutional Review Board for use of human subjects.
Procedures Familiarization Visit During the initial familiarization visit, subjects were familiarized with the warm-up protocol used before all experimental visits. The warm-up included 5 minutes using a cycle ergometer (Precor, Woodinville, WA) at resistance level 5 with a speed of 60 rpm. This was followed by dynamic stretches.
JOURNAL OF THE AMERICAN COLLEGE OF NUTRITION
Subjects then performed a countermovement jump test with 3 consecutive jumps on a forceplate (Fitness Technologies, Skye, South Australia, Australia), which were subsequently analyzed for peak force, power, and velocity (Ballistic Measurement System software, Innervations, Perth, Western Australia). Subjects were instructed to jump as high as possible, maintain hands on hips, and not pause between jumps.
Dietary Counseling Before supplement loading, subjects were asked to complete a trial 3-day diet record, which served as a familiarization. Food records were analyzed for protein content using NutritionistPro software (Axxya Systems, Stafford, TX). Following analysis, subjects received dietary counseling to help maintain a prescribed protein intake of 1 g of protein per kilogram of body mass. Subjects were instructed to follow this prescription during the subsequent 2-week supplement loading phase. Adherence to the dietary prescription was assessed over a 3-day period during the supplement loading phase and a 5day period during the acute testing phase. During the second cycle, adherence was again confirmed during the supplement loading phase, and subjects were asked replicate the 5-day diet used during the first cycle. Analysis of the dietary records
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Additive Effects of HMB and Isomaltulose indicated reasonable adherence to the nutritional guidelines(0.8 to 1.2 g/body weight of daily protein intake, per nutritional analysis).
described warm-up, countermovement jumps were performed. At the beginning of all testing visits, adequate hydration was determined by urine specific gravity 1.025, as measured with a refractometer (Reichert, Lincolnshire, IL).
Supplement Loading Phase
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Three Day Workout Sequence Subjects consumed either RP supplement (260 kcal, 20 g protein, 1.5 g HMB, 41 g carbohydrate, 2 g fat) or whey protein (100 kcal, 20 g protein, 2.5 g carbohydrate, 1 g fat). This isonitrogenous comparison allowed us to examine the additive effects of HMB and carbohydrate, while using commercially available supplements used by competitive and recreational athletes. During the 2-week loading phase, single servings were taken twice daily, once in the morning and once following each workout. On days where no workouts were performed, the supplement was taken in the evening. To ensure compliance with supplement consumption guidelines, subjects were asked to bring empty supplement packets to the lab, and after workouts, supplement consumption was directly monitored. During the first week, subjects performed 3 workouts separated by at least 48 hours of rest. The first workout was a replication of day one of the acute testing protocol that followed (Table 1). The second and third workouts were similar to those used on days 2 and 3, with the only difference being that they were performed with one minute of rest. This was done in an attempt to ensure familiarization with the protocol, while still allowing for novel stimuli during the testing week (where rest was 0.5 minutes). During week 2, only 2 workouts were performed. Again, a replication of day 1 was followed by 48 hours of rest before day 2, where subjects were given one minute of rest between sets.
Baseline Visit Baseline data for muscle soreness and countermovement jump were taken at the end of the supplement loading phase, at least 2 days before the beginning of the acute testing protocol and at least 48 hours following the final workout of the supplement loading phase. Muscle soreness was assessed with a 5point Likert scale during recovery visits, which took place 24 and 48 hours after the last workout. After the previously
The acute testing protocol was performed on 3 consecutive days (workouts described in Table 1). Loading was determined based on a workout log that was filled out during the supplement loading phase and each set was performed to failure. All loads and repetition numbers recorded during cycle one were replicated during the second cycle.
Blood Collection Samples were obtained by venipuncture from an antecubital vein by a trained phlebotomist in the morning between 6:00 and 10:00 AM following a minimum of a 12-hour fast immediately before the workout for the respective visit. Throughout the study, subjects performed all visits at the same time of day. Blood samples were also obtained immediately (IP) and 15 minutes (C15) and 60 minutes (C60) after each workout and then 24 and 48 hours after the last workout, during recovery visits. Blood was collected as serum, which was centrifuged at 1500 £ g at 4 C for 15 minutes. Serum was then aliquoted and stored at ¡80 C.
Biochemistry Creatine kinase was analyzed using creatine kinase–SL assays (SEKISUI, Charlottetown, Canada) with a coefficient of variation (CV) of 3.7%. The assay wavelength was read at 340 nm on a Biomate3 Spectrophotometer (Thermo Scientific, Pittsburgh, PA). Cortisol and testosterone were analyzed using enzyme-linked immunosorbent assays (ELISA; CALBiotech, Spring Valley, CA), with sensitivities of 11.1 and 0.8 nmol/L, respectively. These assays had an intra-and interassay CVs of below 7.2%. IL-6, insulin-like growth factor-1 (IGF-1), and IGFBP3 were analyzed using a Quantikine ELISA (R&D Systems, Minneapolis, MN). The assays had sensitivities of 0.06 pg/mL, 0.026 ng/mL, and 0.05 ng/mL. Intra-assay CVs
Table 1. Three-Day Workout Sequencea Day 1: Heavy Exercise
Sets
Barbell squat Bench press Bent over row Deadlift Shoulder press Lateral pulldown
5 5 3 3 2 2
a
Day 2: Metabolic
Day 3: Metabolic
Repetitions
Rest (min)
Sets
Repetitions
Rest (min)
Sets
Repetitions
Rest (min)
3–5 3–5 3–5 3–5 6–8 6–8
3 3 3 3 2 2
3 3 3 3 3 3
8–10 8–10 8–10 8–10 8–10 8–10
0.5 0.5 0.5 0.5 0.5 0.5
3 3 3 3 3 3
8–10 8–10 8–10 8–10 8–10 8–10
0.5 0.5 0.5 0.5 0.5 0.5
Workouts were performed on consecutive days at the same time of day. Rest period represents time in minutes between each set.
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Additive Effects of HMB and Isomaltulose depicted in Fig. 4, countermovement jump power was significantly greater when subjects consumed RP, with values that did not differ from baseline (p 0.05). Moreover, despite significant increases in soreness from baseline in both groups, perceived soreness was significantly lower in RP at 24 hours (p 0.05; Fig. 5).
were 6.2%, 4.1%, and 4.6%, and interassay CVs were 8.3%, 5.7%, and 6.2%, respectively. All ELISAs were measured in duplicate on a Versamax tunable microplate reader (Molecular Devices, Sunnyvale, CA) at the appropriate wavelength for that particular assay.
Statistical Analyses
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A repeated measures analysis of variance was used for the selected dependent variables. Linear assumptions were tested and, if necessary, a Huynh-Feldt sphericity correction was applied. The variable (IL-6) that failed the test for normality after correction was logarithmically transformed and tested again. Pairwise comparisons were made with Bonferroni post hoc tests. Statistical analyses were completed using the nQuery Advisor software (Statistical Solutions, Saugus, MA). Statistical power for our sample size ranged from 0.76 to 0.87. Significance was set a priori at p 0.05.
DISCUSSION The primary finding of this study is that when high loads and short periods are used during high-frequency resistance exercise, the addition of HMB and a slow-release carbohydrate to WP is more effective than WP alone at promoting recovery. This was evidenced not only by reductions in indirect markers muscle damage but by reductions in muscle soreness and improved physical performance. Though WP has previously been shown to increase lean body mass [6], increased training demands may require further supplement optimization. Subjects in the aforementioned study generally trained for 3 nonconsecutive days per week, whereas subjects in the present study exercised on 3 consecutive days, with shorter rest periods. The relative advantage of WP is likely due to its higher leucine content, but when greater demands are placed on the body’s recovery processes, the addition of a leucine derivative (HMB) to WP may improve the efficacy of the supplement. HMB has also been shown effective in reducing markers of muscle damage following one session [16], 3 weeks [14], and 4 weeks [15] of resistance training performed 3 days per week. However, in these studies a significant difference in CK activity was not seen until the third or fourth week. In the present
RESULTS We observed significant differences between supplements that were mostly confined to the recovery visits, which took place 24 and 48 hours after the third workout of the acute testing protocol. A comprehensive summary of observed circulating hormone concentrations is provided in Table 2. Circulating CK was significantly lower with RP at rest on day 2 and during the 24-and 48-hour recovery visits when compared to WP (p 0.05; see Fig. 2). During both recovery visits, IL-6 was also significantly lower in the RP group (p 0.05; see Fig. 3). As Table 2. Hormonal Response Dataa Testosterone (nmol¢L¡1) Day Time 1
2
3
4 5
Pre IP 15 60 Pre IP 15 60 Pre IP 15 60 C24 C48
WP 20.1 22.5 21.7 19.9 20.4 24.9 24.1 19.2 19.6 25.6 24.2 19.4 20.4 21.7
§ 6.8 § 8.9 § 8.1 § 8.2 § 5.8 § 9.8 § 8.8 § 6.7 § 5.1 § 9.7 § 8.5 § 6.1 § 6.3 § 4.8
IGF-1 (ng¢ml¡1)
RP 20.9 23.5 22.3 20.4 20.8 24.9 24.9 18.0 20.5 25.8 24.9 19.6 21.5 20.7
§ 4.9 § 8.6 § 6.8 § 5.8 § 4.7 § 8.5 § 8.3 § 5.3 § 4.3 § 7.8 § 6.4 § 6.0 § 6.0 § 5.8
WP
IGFBP3 (ng¢ml¡1)
RP
WP
RP
172.0 § 40.3 178.1 § 37.0 2338.0 § 557.0 2396.0 § 479.0 187.6 § 30.6 192.3 § 31.0 2688.0 § 593.0 2812.0 § 637.0 170.6 § 34.0 173.4 § 35.9 2357.0 § 549.0 2368.0 § 595.0 b
b
b
b
176.7 § 40.4 180.1 § 39.0 2435.0 § 479.0 2317.0 § 537.0 192.7 § 43.8 199.6 § 37.7 2978.0 § 692.0 2901.0 § 631.0 172.4 § 39.3 175.6 § 35.2 2302.0 § 642.0 2302.0 § 542.0 b
b
b
b
181.0 § 39.5 175.2 § 36.2 2260.0 § 459.0 2245.0 § 530.0 195.2 § 40.0 200.2 § 34.8 2724.0 § 662.0 2789.0 § 691.0 168.3 § 36.5 176.5 § 33.4 2269.0 § 542.0 2248.0 § 586.0
b
b
b
Cortisol (nmol¢L¡1)
b
179.0 § 47.8 177.2 § 31.5 2280.0 § 476.0 2300.0 § 542.0 172.7 § 34.9 168.3 § 37.9 2221.0 § 454.0 2341.0 § 578.0
WP 447.0 584.0 558.0 497.0 609.0 858.0 1157.0 920.0 698.0 886.0 991.0 661.0 654.0 529.0
RP
§ 106.0 475.0 § 114.0 § 241.0 582.0 § 206.0 § 213.0 554.0 § 224.0 § 186.0 391.0 § 154.0 636.0 § 222.0* § 181.0* * § 360.0 871.0 § 288.0*y § 346.0*y 1103.0 § 267.0*y § 374.0*y 915.0 § 311.0* § 282.0* 633.0 § 196.0* * § 295.0 853.0 § 299.0*y § 373.0*y 1001.0 § 352.0*y § 270.0 621.0 § 218.0* § 144.0* 609.0 § 174.0* § 154.0 538.0 § 115.0
IGF-1 D insulin-like growth factor-1, WP D whey protein, RP D recovery protein. a Circulating hormone concentrations measured in the blood at time points surrounding the workout sequence. Data are presented as mean § SD. b Samples were not measured at these time points. *Significantly (p 0.05) different from corresponding day 1 pre. y Significantly (p 0.05) different from preworkout value from corresponding visit.
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Fig. 2. Effect of EAS recovery protein vs whey protein on blood serum creatine kinase concentrations during a 3-day workout sequence. #Significant (p 0.05) difference between treatments at corresponding time point.
study, significant differences were seen after 3 days of resistance training. The study by Nissen et al. [14] compared HMB to a control supplement with no protein, whereas this study compared the addition of HMB to aWP supplement. This comparison highlights the additive effects of HMB and WP under conditions of heightened training demands and provides further support for the theory that the treatment effects of HMB and WP are driven by leucine content. Although this study provided further support for the role of HMB in cell membrane stability, no between-group differences were observed in terms of the other blood hormones. Thus, this study does not provide indirect evidence for a role of IGF-1 in
enhanced protein synthesis or for reduced glucocorticoid activity and protein degradation, which have been inconsistently shown in past work [10,16] (Table 2). Prior evidence for a role of HMB in these mechanisms has been observed in cell culture or animal models. Because increases in circulating HMB after ingestion are likely smaller than those observed when used in vitro, the supplement may have failed to adequately stimulate IGF-1 and mammalian target of rapamycin (mTOR) activity or suppress cortisol activity. Alternatively, such responses may occur in muscle tissue but without detectable effects on circulating hormone concentrations. Nevertheless, it is important to note that long-term improvements in muscle mass and strength have been shown in
Fig. 3. Effect of EAS recovery protein vs whey protein on blood serum interleukin-6 concentrations during a 3-day workout sequence. #Significant (p 0.05) difference between treatments at corresponding time point. *Significant (p 0.05) difference from corresponding pre-exercise value.
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Fig. 4. Effect of EAS recovery protein vs whey protein on countermovement vertical jump performance during a 3-day workout sequence. #Significant (p 0.05) difference between treatments at corresponding time point.
elderly women [25] and untrained men [26] with HMB supplementation. This suggests that if the growth factor response is not the primary biological mechanism of action, improvements in cell membrane integrity transfer to measurable differences in long-term strength and muscle mass, in addition to acute improvements in muscle damage, performance, and important perceptual factors, as observed in this and past work [16]. Although WP and RP did not differ with respect to circulating hormone concentrations, WP alone may be suboptimal in supporting recovery when resistance training is highly glycolytic. IL-6 is often elevated during times of glycogen depletion [20,21], and carbohydrate supplementation has been demonstrated to attenuate this
response [21]. Although cytokine responses have been studied to a greater extent in endurance activities, elevations in IL-6 have also been observed following resistance training [22,23]. Interestingly, the IL-6 concentrations measured in these studies were much greater than those observed in the present study (7.72 and 4.5 pg/ ml, respectively, vs 2.2 pg/ml). These differences may reflect the greater volume [22] or untrained subjects used by others [23]. Irrespective of the lower IL-6 concentrations observed in this study, the addition of a slow-release carbohydrate to WP was effective at attenuating the IL-6 response. This suggests that the addition of isomaltulose to WP may be beneficial during times of increased training volume, as well as in previously untrained subjects.
Fig. 5. Effect of EAS recovery protein vs whey protein perceived muscle soreness during a 3-day workout sequence. #Significant (p 0.05) difference between treatments at corresponding time point. *Significantly (p 0.05) different from baseline value for corresponding treatment. ySignificantly (p 0.05) different from 24-hour value for corresponding treatment.
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CONCLUSION When resistance training combines high training frequencies with high loads and short rest periods, a greater demand is placed on the body’s recovery processes, which increases the need for supplementation. Although WP alone has been shown to be an effective supplement, the addition of HMB and a slow-release carbohydrate further mediates the recovery process, as evidenced by reduced muscle damage, lower perceived soreness, and improved athletic performance.
ACKNOWLEDGMENTS
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The authors wish to thank a dedicated group of subjects and research team members who made this study possible.
FUNDING This study was funded in part by a grant from EAS Sports Nutrition, Abbott Laboratories, Columbus, OH.
AUTHOR NOTE Current affiliations are as follows: Brian R. Kupchak - U.S. Naval Research Laboratory, Bethesda, MD; Courtenay DunnLewis, -Merrimack College, North Andover, MA; Brett A. Comstock - University of South Dakota, Vermilion SD; Adam J. Sterczala - University of Kansas, Lawrence, KS; Hiu-Ying Luk- University of North Texas, Denton, TX.
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The Addition of Beta-hydroxy-beta-methylbutyrate and Isomaltulose to Whey Protein Improves Recovery from Highly Demanding Resistance Exercise a
a
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William J. Kraemer PhD FACN , David R. Hooper MA , Tunde K. Szivak MA , Brian R. Kupchak b
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PhD , Courtenay Dunn-Lewis PhD , Brett A. Comstock PhD , Shawn D. Flanagan MA MHA , b
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David P. Looney MS , Adam J. Sterczala MS , William H. DuPont MS , J. Luke Pryor MS , Hiub
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a
Ying Luk MS , Jesse Maladoungdock MS , Danielle McDermott MS , Jeff S. Volek PhD RD & a
Carl M. Maresh PhD a
Department of Human Sciences, The Ohio State University, Columbus, Ohio
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Human Performance Laboratory, Department of Kinesiology, Storrs, Connecticut Published online: 11 Mar 2015.
To cite this article: William J. Kraemer PhD FACN, David R. Hooper MA, Tunde K. Szivak MA, Brian R. Kupchak PhD, Courtenay Dunn-Lewis PhD, Brett A. Comstock PhD, Shawn D. Flanagan MA MHA, David P. Looney MS, Adam J. Sterczala MS, William H. DuPont MS, J. Luke Pryor MS, Hiu-Ying Luk MS, Jesse Maladoungdock MS, Danielle McDermott MS, Jeff S. Volek PhD RD & Carl M. Maresh PhD (2015) The Addition of Beta-hydroxy-beta-methylbutyrate and Isomaltulose to Whey Protein Improves Recovery from Highly Demanding Resistance Exercise, Journal of the American College of Nutrition, 34:2, 91-99, DOI: 10.1080/07315724.2014.938790 To link to this article: http://dx.doi.org/10.1080/07315724.2014.938790
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Original Research
The Addition of Beta-hydroxy-beta-methylbutyrate and Isomaltulose to Whey Protein Improves Recovery from Highly Demanding Resistance Exercise
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William J. Kraemer, PhD, David R. Hooper, MA, Tunde K. Szivak, MA, Brian R. Kupchak, PhD, Courtenay Dunn-Lewis, PhD, Brett A. Comstock, PhD, Shawn D. Flanagan, MA, MHA, David P. Looney, MS, Adam J. Sterczala, MS, William H. DuPont, MS, J. Luke Pryor, MS, Hiu-Ying Luk, MS, Jesse Maladoungdock, MS, Danielle McDermott, MS, Jeff S. Volek, PhD, RD, Carl M. Maresh, PhD Department of Human Sciences, The Ohio State University, Columbus, Ohio (W.J.K, D.R.H., T.K.S., S.D.F., W.H.D., J.S.V., C.M.M.); Human Performance Laboratory, Department of Kinesiology, University of Connecticut, Storrs, Connecticut (B.R.K., C.D.-L., B.A.C., D.P.L., A.J.S., J.L.P., H.-Y.L., J.M., D.M.) Key words: resistance training, HMB, whey protein, carbohydrate, muscle damage, exercise Objective: This study evaluated whether a combination of whey protein (WP), calcium beta-hydroxy-betamethylbutyrate (HMB), and carbohydrate exert additive effects on recovery from highly demanding resistance exercise. Methods: Thirteen resistance-trained men (age: 22.6 § 3.9 years; height: 175.3 § 12.2 cm; weight: 86.2 § 9.8 kg) completed a double-blinded, counterbalanced, within-group study. Subjects ingested EAS Recovery Protein (RP; EAS Sports Nutrition/Abbott Laboratories, Columbus, OH) or WP twice daily for 2 weeks prior to, during, and for 2 days following 3 consecutive days of intense resistance exercise. The workout sequence included heavy resistance exercise (day 1) and metabolic resistance exercise (days 2 and 3). The subjects performed no physical activity during day 4 (C24 hours) and day 5 (C48 hours), where recovery testing was performed. Before, during, and following the 3 workouts, treatment outcomes were evaluated using blood-based muscle damage markers and hormones, perceptual measures of muscle soreness, and countermovement jump performance. Results: Creatine kinase was lower for the RP treatment on day 2 (RP: 166.9 § 56.4 vs WP: 307.1 § 125.2 IU ¢ L¡1, p 0.05), day 4 (RP: 232.5 § 67.4 vs WP: 432.6 § 223.3 IU ¢ L¡1, p 0.05), and day 5 (RP: 176.1 § 38.7 vs 264.5 § 120.9 IU ¢ L¡1, p 0.05). Interleukin-6 was lower for the RP treatment on day 4 (RP: 1.2 § 0.2 vs WP: 1.6 § 0.6 pg ¢ ml¡1, p 0.05) and day 5 (RP: 1.1 § 0.2 vs WP: 1.6 § 0.4 pg ¢ ml¡1, p 0.05). Muscle soreness was lower for RP treatment on day 4 (RP: 2.0 § 0.7 vs WP: 2.8 § 1.1 cm, p 0.05). Vertical jump power was higher for the RP treatment on day 4 (RP: 5983.2 § 624 vs WP 5303.9 § 641.7 W, p 0.05) and day 5 (RP: 5792.5 § 595.4 vs WP: 5200.4 § 501 W, p 0.05). Conclusions: Our findings suggest that during times of intense conditioning, the recovery benefits of WP are enhanced with the addition of HMB and a slow-release carbohydrate. We observed reductions in markers of muscle damage and improved athletic performance.
INTRODUCTION
support [1,2]. Further, athletes may fail to balance training and recovery as they strive for maximal performance [3]. When excessive stress is placed on the body’s recovery process, which can no longer compensate, reductions in strength, overtraining syndrome [3], and possibly even injury (such as rhabdomyolysis) may occur. Various dietary supplements have been
In order to maximize adaptations to resistance exercise, progressive increases in training loads and frequency are typically recommended, along with the use of periodization [1]. Rigorous conditioning sequences may require additional nutritional
Address correspondence to: William J. Kraemer, PhD, FACN, Department of Human Sciences, The Ohio State University, A054 PAES Bldg, 305 West 17th Ave, Columbus, OH 43210. E-mail: [email protected] Abbreviations: WP D whey protein, RP D recovery protein, HMB D beta-hydroxy-beta-methylbutyrate
Journal of the American College of Nutrition, Vol. 34, No. 2, 91–99 (2015) Ó American College of Nutrition Published by Taylor & Francis Group, LLC 91
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Additive Effects of HMB and Isomaltulose developed to support the recovery process by reducing muscle damage and the loss of physical performance. Protein supplementation is a prominent example: though resistance training has been shown to increase protein synthesis [4], net protein balance may remain negative without the use of a protein supplement afteracute resistance exercise [5]. Different types of protein have been studied, including proteins from different sources (e.g., whey and soy based). In a recent study, we directly compared 2 sources of protein and demonstrated that despite isocaloric and isonitrogenous conditions, lean body mass gains were greater in subjects who supplemented with whey [6]. The mechanism for this preferential response to whey protein may reflect increased branched-chain amino acid content, and leucine in particular, because these amino acids activate key protein synthesis enzymes after physical exercise [7]. This theory was echoed in a recent review, where it was suggested that leucine may be responsible for the efficacy of protein supplements, as opposed to brain chain amino acids (BCAAs) generally [8]. A possible explanation for the superiority of leucine over other amino acids lies in its metabolite, beta-hydroxy-beta-methylbutyrate (HMB), produced from the reversible transamination of leucine to a-ketoisocaproate (KIC) [9], followed by production of HMB in the cytosol. KIC can also be metabolized in the mitochondria [10], yet both pathways lead to the production of hydroxymethylglutaryl-coenzyme A (HMG-CoA), a precursor for cholesterol synthesis. The current model for HMB in recovery is that damaged muscle cells are unable to produce enough HMG-CoA (and therefore cholesterol) to function properly [10]. As a result, HMB supplementation may stabilize cellular membranes, allowing for maximal cell growth [11]. The ability of HMB to stabilize membranes is supported by its ability to reduce circulating creatine kinase (CK), an intracellular enzyme thought to increase with cell membrane permeability as a result of skeletal muscle damage [12]. The ability of HMB to aid the recovery process following resistance training could thus play an important role, because it has been suggested that CK should return to normal in order to avoid overtraining or muscular pathology [13]. Accordingly, with 3 weekly days of resistance training, Nissen et al. [14] demonstrated significantly lower plasma CK in subjects who consumed HMB compared to a control group. These results were duplicated in more recent work, which showed that HMB supplementation is accompanied by significant reductions in CK with one session or 12 weeks of resistance training [15,16]. Additional proposed mechanisms for the role of HMB in strength improvement are focused on HMB’s ability to improve net protein balance by altering anabolic, catabolic, and inflammatory factors [10]. Until recently, studies in this area had predominantly utilized cell cultures or animal models. However, Wilkinson et al. [17] confirmed elevated muscle protein synthesis as well as attenuated muscle protein breakdown with HMB and leucine supplementation in vivo. Furthermore, it was recently demonstrated that HMB
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could reduce circulating tumor necrosis factor-a (TNF-a) and monocyte TNF-a receptor 1 expression after intense exercise, indicating that HMB may positively alter the immune response to exercise [18]. In addition to whey protein (WP) and HMB, carbohydrate supplementation also appears to have beneficial effects on recovery, which may stem from actions on circulating cytokines, including interleukin-6 (IL-6). These messenger molecules are released from muscle and various lymphocytes and are associated with altered metabolic activity, which may in turn promote inflammatory immune activity [19]. For example, elevations in IL-6 are associated with glycogen depletion [20], and carbohydrate supplementation can attenuate this response following long-distance running [21]. Though glycogen depletion is typically associated with endurance activities, resistance training can also challenge glycolysis, especially when short rest intervals are used. To that end, elevations in IL-6 have been observed from immediately post to upwards of an hour after resistance exercise [22], as well as up to 72 hours later [23]. Such prolonged increases in IL-6 would be of concern to individuals engaging in extreme conditioning protocols, where high training frequencies are also typically employed (5–6 times per week). In such cases, resistance training with high glycolytic demands performed at high frequencies could result in chronically elevated resting IL-6 concentrations, which may have detrimental effects on metabolism and inflammation [24]. As a result, recovery from repeated resistance training workouts, especially those that demand more glycolytic metabolism, might be aided by supplementation with carbohydrates and especially those metabolized more slowly, such as isomaltulose. Despite the profound benefits of resistance training on health and performance, in certain circumstances, excessive demands can be placed on the recovery process. Though WP has been shown to be an effective supplement, resistance training protocols with high volume, frequency, and glycolytic demands may place greater stress on recovery than the traditional workouts that have been used to study WP. Therefore, the purpose of this study was to compare recovery from highly demanding resistance exercise with WP or a supplement containing whey, HMB, and a slow-release carbohydrate (isomaltulose).
MATERIALS AND METHODS This investigation examined EAS Recovery Protein (RP; EAS Sports Nutrition/Abbott Laboratories, Columbus, OH), a nutritional supplement containing calcium beta-hydroxy-betamethylbutyrate (HMB), isomaltulose, and whey protein. A double-blind, counterbalanced within-group design was used to evaluate whether RP was able to offset indirect markers of tissue disruption caused by intense resistance exercise better than WP alone (see Fig. 1). The recovery process was assessed using blood markers of muscle damage (CK), blood hormone
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Additive Effects of HMB and Isomaltulose
Fig. 1. Study design: (A) visit sequence and (B) timeline of the acute testing protocol.
concentrations of potential therapeutic targets, perception of muscle soreness, and countermovement jump performance.
Subjects Thirteen men (age: 22.6 § 3.9 years; height: 175.3 § 12.2 cm; weight: 86.2 § 9.8 kg) with at least one year of resistance training experience volunteered to participate in the study. Height was measured using a stadiometer (Seca, Hamburg, Germany). Weight was measured using a calibrated scale (OHAUS Corp., Florham Park, NJ). All subjects were fully informed of the protocol design and associated risks of this investigation before signing an informed consent approved by the University of Connecticut Institutional Review Board for use of human subjects.
Procedures Familiarization Visit During the initial familiarization visit, subjects were familiarized with the warm-up protocol used before all experimental visits. The warm-up included 5 minutes using a cycle ergometer (Precor, Woodinville, WA) at resistance level 5 with a speed of 60 rpm. This was followed by dynamic stretches.
JOURNAL OF THE AMERICAN COLLEGE OF NUTRITION
Subjects then performed a countermovement jump test with 3 consecutive jumps on a forceplate (Fitness Technologies, Skye, South Australia, Australia), which were subsequently analyzed for peak force, power, and velocity (Ballistic Measurement System software, Innervations, Perth, Western Australia). Subjects were instructed to jump as high as possible, maintain hands on hips, and not pause between jumps.
Dietary Counseling Before supplement loading, subjects were asked to complete a trial 3-day diet record, which served as a familiarization. Food records were analyzed for protein content using NutritionistPro software (Axxya Systems, Stafford, TX). Following analysis, subjects received dietary counseling to help maintain a prescribed protein intake of 1 g of protein per kilogram of body mass. Subjects were instructed to follow this prescription during the subsequent 2-week supplement loading phase. Adherence to the dietary prescription was assessed over a 3-day period during the supplement loading phase and a 5day period during the acute testing phase. During the second cycle, adherence was again confirmed during the supplement loading phase, and subjects were asked replicate the 5-day diet used during the first cycle. Analysis of the dietary records
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Additive Effects of HMB and Isomaltulose indicated reasonable adherence to the nutritional guidelines(0.8 to 1.2 g/body weight of daily protein intake, per nutritional analysis).
described warm-up, countermovement jumps were performed. At the beginning of all testing visits, adequate hydration was determined by urine specific gravity 1.025, as measured with a refractometer (Reichert, Lincolnshire, IL).
Supplement Loading Phase
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Three Day Workout Sequence Subjects consumed either RP supplement (260 kcal, 20 g protein, 1.5 g HMB, 41 g carbohydrate, 2 g fat) or whey protein (100 kcal, 20 g protein, 2.5 g carbohydrate, 1 g fat). This isonitrogenous comparison allowed us to examine the additive effects of HMB and carbohydrate, while using commercially available supplements used by competitive and recreational athletes. During the 2-week loading phase, single servings were taken twice daily, once in the morning and once following each workout. On days where no workouts were performed, the supplement was taken in the evening. To ensure compliance with supplement consumption guidelines, subjects were asked to bring empty supplement packets to the lab, and after workouts, supplement consumption was directly monitored. During the first week, subjects performed 3 workouts separated by at least 48 hours of rest. The first workout was a replication of day one of the acute testing protocol that followed (Table 1). The second and third workouts were similar to those used on days 2 and 3, with the only difference being that they were performed with one minute of rest. This was done in an attempt to ensure familiarization with the protocol, while still allowing for novel stimuli during the testing week (where rest was 0.5 minutes). During week 2, only 2 workouts were performed. Again, a replication of day 1 was followed by 48 hours of rest before day 2, where subjects were given one minute of rest between sets.
Baseline Visit Baseline data for muscle soreness and countermovement jump were taken at the end of the supplement loading phase, at least 2 days before the beginning of the acute testing protocol and at least 48 hours following the final workout of the supplement loading phase. Muscle soreness was assessed with a 5point Likert scale during recovery visits, which took place 24 and 48 hours after the last workout. After the previously
The acute testing protocol was performed on 3 consecutive days (workouts described in Table 1). Loading was determined based on a workout log that was filled out during the supplement loading phase and each set was performed to failure. All loads and repetition numbers recorded during cycle one were replicated during the second cycle.
Blood Collection Samples were obtained by venipuncture from an antecubital vein by a trained phlebotomist in the morning between 6:00 and 10:00 AM following a minimum of a 12-hour fast immediately before the workout for the respective visit. Throughout the study, subjects performed all visits at the same time of day. Blood samples were also obtained immediately (IP) and 15 minutes (C15) and 60 minutes (C60) after each workout and then 24 and 48 hours after the last workout, during recovery visits. Blood was collected as serum, which was centrifuged at 1500 £ g at 4 C for 15 minutes. Serum was then aliquoted and stored at ¡80 C.
Biochemistry Creatine kinase was analyzed using creatine kinase–SL assays (SEKISUI, Charlottetown, Canada) with a coefficient of variation (CV) of 3.7%. The assay wavelength was read at 340 nm on a Biomate3 Spectrophotometer (Thermo Scientific, Pittsburgh, PA). Cortisol and testosterone were analyzed using enzyme-linked immunosorbent assays (ELISA; CALBiotech, Spring Valley, CA), with sensitivities of 11.1 and 0.8 nmol/L, respectively. These assays had an intra-and interassay CVs of below 7.2%. IL-6, insulin-like growth factor-1 (IGF-1), and IGFBP3 were analyzed using a Quantikine ELISA (R&D Systems, Minneapolis, MN). The assays had sensitivities of 0.06 pg/mL, 0.026 ng/mL, and 0.05 ng/mL. Intra-assay CVs
Table 1. Three-Day Workout Sequencea Day 1: Heavy Exercise
Sets
Barbell squat Bench press Bent over row Deadlift Shoulder press Lateral pulldown
5 5 3 3 2 2
a
Day 2: Metabolic
Day 3: Metabolic
Repetitions
Rest (min)
Sets
Repetitions
Rest (min)
Sets
Repetitions
Rest (min)
3–5 3–5 3–5 3–5 6–8 6–8
3 3 3 3 2 2
3 3 3 3 3 3
8–10 8–10 8–10 8–10 8–10 8–10
0.5 0.5 0.5 0.5 0.5 0.5
3 3 3 3 3 3
8–10 8–10 8–10 8–10 8–10 8–10
0.5 0.5 0.5 0.5 0.5 0.5
Workouts were performed on consecutive days at the same time of day. Rest period represents time in minutes between each set.
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Additive Effects of HMB and Isomaltulose depicted in Fig. 4, countermovement jump power was significantly greater when subjects consumed RP, with values that did not differ from baseline (p 0.05). Moreover, despite significant increases in soreness from baseline in both groups, perceived soreness was significantly lower in RP at 24 hours (p 0.05; Fig. 5).
were 6.2%, 4.1%, and 4.6%, and interassay CVs were 8.3%, 5.7%, and 6.2%, respectively. All ELISAs were measured in duplicate on a Versamax tunable microplate reader (Molecular Devices, Sunnyvale, CA) at the appropriate wavelength for that particular assay.
Statistical Analyses
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A repeated measures analysis of variance was used for the selected dependent variables. Linear assumptions were tested and, if necessary, a Huynh-Feldt sphericity correction was applied. The variable (IL-6) that failed the test for normality after correction was logarithmically transformed and tested again. Pairwise comparisons were made with Bonferroni post hoc tests. Statistical analyses were completed using the nQuery Advisor software (Statistical Solutions, Saugus, MA). Statistical power for our sample size ranged from 0.76 to 0.87. Significance was set a priori at p 0.05.
DISCUSSION The primary finding of this study is that when high loads and short periods are used during high-frequency resistance exercise, the addition of HMB and a slow-release carbohydrate to WP is more effective than WP alone at promoting recovery. This was evidenced not only by reductions in indirect markers muscle damage but by reductions in muscle soreness and improved physical performance. Though WP has previously been shown to increase lean body mass [6], increased training demands may require further supplement optimization. Subjects in the aforementioned study generally trained for 3 nonconsecutive days per week, whereas subjects in the present study exercised on 3 consecutive days, with shorter rest periods. The relative advantage of WP is likely due to its higher leucine content, but when greater demands are placed on the body’s recovery processes, the addition of a leucine derivative (HMB) to WP may improve the efficacy of the supplement. HMB has also been shown effective in reducing markers of muscle damage following one session [16], 3 weeks [14], and 4 weeks [15] of resistance training performed 3 days per week. However, in these studies a significant difference in CK activity was not seen until the third or fourth week. In the present
RESULTS We observed significant differences between supplements that were mostly confined to the recovery visits, which took place 24 and 48 hours after the third workout of the acute testing protocol. A comprehensive summary of observed circulating hormone concentrations is provided in Table 2. Circulating CK was significantly lower with RP at rest on day 2 and during the 24-and 48-hour recovery visits when compared to WP (p 0.05; see Fig. 2). During both recovery visits, IL-6 was also significantly lower in the RP group (p 0.05; see Fig. 3). As Table 2. Hormonal Response Dataa Testosterone (nmol¢L¡1) Day Time 1
2
3
4 5
Pre IP 15 60 Pre IP 15 60 Pre IP 15 60 C24 C48
WP 20.1 22.5 21.7 19.9 20.4 24.9 24.1 19.2 19.6 25.6 24.2 19.4 20.4 21.7
§ 6.8 § 8.9 § 8.1 § 8.2 § 5.8 § 9.8 § 8.8 § 6.7 § 5.1 § 9.7 § 8.5 § 6.1 § 6.3 § 4.8
IGF-1 (ng¢ml¡1)
RP 20.9 23.5 22.3 20.4 20.8 24.9 24.9 18.0 20.5 25.8 24.9 19.6 21.5 20.7
§ 4.9 § 8.6 § 6.8 § 5.8 § 4.7 § 8.5 § 8.3 § 5.3 § 4.3 § 7.8 § 6.4 § 6.0 § 6.0 § 5.8
WP
IGFBP3 (ng¢ml¡1)
RP
WP
RP
172.0 § 40.3 178.1 § 37.0 2338.0 § 557.0 2396.0 § 479.0 187.6 § 30.6 192.3 § 31.0 2688.0 § 593.0 2812.0 § 637.0 170.6 § 34.0 173.4 § 35.9 2357.0 § 549.0 2368.0 § 595.0 b
b
b
b
176.7 § 40.4 180.1 § 39.0 2435.0 § 479.0 2317.0 § 537.0 192.7 § 43.8 199.6 § 37.7 2978.0 § 692.0 2901.0 § 631.0 172.4 § 39.3 175.6 § 35.2 2302.0 § 642.0 2302.0 § 542.0 b
b
b
b
181.0 § 39.5 175.2 § 36.2 2260.0 § 459.0 2245.0 § 530.0 195.2 § 40.0 200.2 § 34.8 2724.0 § 662.0 2789.0 § 691.0 168.3 § 36.5 176.5 § 33.4 2269.0 § 542.0 2248.0 § 586.0
b
b
b
Cortisol (nmol¢L¡1)
b
179.0 § 47.8 177.2 § 31.5 2280.0 § 476.0 2300.0 § 542.0 172.7 § 34.9 168.3 § 37.9 2221.0 § 454.0 2341.0 § 578.0
WP 447.0 584.0 558.0 497.0 609.0 858.0 1157.0 920.0 698.0 886.0 991.0 661.0 654.0 529.0
RP
§ 106.0 475.0 § 114.0 § 241.0 582.0 § 206.0 § 213.0 554.0 § 224.0 § 186.0 391.0 § 154.0 636.0 § 222.0* § 181.0* * § 360.0 871.0 § 288.0*y § 346.0*y 1103.0 § 267.0*y § 374.0*y 915.0 § 311.0* § 282.0* 633.0 § 196.0* * § 295.0 853.0 § 299.0*y § 373.0*y 1001.0 § 352.0*y § 270.0 621.0 § 218.0* § 144.0* 609.0 § 174.0* § 154.0 538.0 § 115.0
IGF-1 D insulin-like growth factor-1, WP D whey protein, RP D recovery protein. a Circulating hormone concentrations measured in the blood at time points surrounding the workout sequence. Data are presented as mean § SD. b Samples were not measured at these time points. *Significantly (p 0.05) different from corresponding day 1 pre. y Significantly (p 0.05) different from preworkout value from corresponding visit.
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Fig. 2. Effect of EAS recovery protein vs whey protein on blood serum creatine kinase concentrations during a 3-day workout sequence. #Significant (p 0.05) difference between treatments at corresponding time point.
study, significant differences were seen after 3 days of resistance training. The study by Nissen et al. [14] compared HMB to a control supplement with no protein, whereas this study compared the addition of HMB to aWP supplement. This comparison highlights the additive effects of HMB and WP under conditions of heightened training demands and provides further support for the theory that the treatment effects of HMB and WP are driven by leucine content. Although this study provided further support for the role of HMB in cell membrane stability, no between-group differences were observed in terms of the other blood hormones. Thus, this study does not provide indirect evidence for a role of IGF-1 in
enhanced protein synthesis or for reduced glucocorticoid activity and protein degradation, which have been inconsistently shown in past work [10,16] (Table 2). Prior evidence for a role of HMB in these mechanisms has been observed in cell culture or animal models. Because increases in circulating HMB after ingestion are likely smaller than those observed when used in vitro, the supplement may have failed to adequately stimulate IGF-1 and mammalian target of rapamycin (mTOR) activity or suppress cortisol activity. Alternatively, such responses may occur in muscle tissue but without detectable effects on circulating hormone concentrations. Nevertheless, it is important to note that long-term improvements in muscle mass and strength have been shown in
Fig. 3. Effect of EAS recovery protein vs whey protein on blood serum interleukin-6 concentrations during a 3-day workout sequence. #Significant (p 0.05) difference between treatments at corresponding time point. *Significant (p 0.05) difference from corresponding pre-exercise value.
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Fig. 4. Effect of EAS recovery protein vs whey protein on countermovement vertical jump performance during a 3-day workout sequence. #Significant (p 0.05) difference between treatments at corresponding time point.
elderly women [25] and untrained men [26] with HMB supplementation. This suggests that if the growth factor response is not the primary biological mechanism of action, improvements in cell membrane integrity transfer to measurable differences in long-term strength and muscle mass, in addition to acute improvements in muscle damage, performance, and important perceptual factors, as observed in this and past work [16]. Although WP and RP did not differ with respect to circulating hormone concentrations, WP alone may be suboptimal in supporting recovery when resistance training is highly glycolytic. IL-6 is often elevated during times of glycogen depletion [20,21], and carbohydrate supplementation has been demonstrated to attenuate this
response [21]. Although cytokine responses have been studied to a greater extent in endurance activities, elevations in IL-6 have also been observed following resistance training [22,23]. Interestingly, the IL-6 concentrations measured in these studies were much greater than those observed in the present study (7.72 and 4.5 pg/ ml, respectively, vs 2.2 pg/ml). These differences may reflect the greater volume [22] or untrained subjects used by others [23]. Irrespective of the lower IL-6 concentrations observed in this study, the addition of a slow-release carbohydrate to WP was effective at attenuating the IL-6 response. This suggests that the addition of isomaltulose to WP may be beneficial during times of increased training volume, as well as in previously untrained subjects.
Fig. 5. Effect of EAS recovery protein vs whey protein perceived muscle soreness during a 3-day workout sequence. #Significant (p 0.05) difference between treatments at corresponding time point. *Significantly (p 0.05) different from baseline value for corresponding treatment. ySignificantly (p 0.05) different from 24-hour value for corresponding treatment.
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CONCLUSION When resistance training combines high training frequencies with high loads and short rest periods, a greater demand is placed on the body’s recovery processes, which increases the need for supplementation. Although WP alone has been shown to be an effective supplement, the addition of HMB and a slow-release carbohydrate further mediates the recovery process, as evidenced by reduced muscle damage, lower perceived soreness, and improved athletic performance.
ACKNOWLEDGMENTS
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The authors wish to thank a dedicated group of subjects and research team members who made this study possible.
FUNDING This study was funded in part by a grant from EAS Sports Nutrition, Abbott Laboratories, Columbus, OH.
AUTHOR NOTE Current affiliations are as follows: Brian R. Kupchak - U.S. Naval Research Laboratory, Bethesda, MD; Courtenay DunnLewis, -Merrimack College, North Andover, MA; Brett A. Comstock - University of South Dakota, Vermilion SD; Adam J. Sterczala - University of Kansas, Lawrence, KS; Hiu-Ying Luk- University of North Texas, Denton, TX.
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