Ryan P. Lowery

Meta-analysis of postactivation potentiation and power: effects of conditioning activity, volume, gender, rest periods, and training status.

Abstract Wilson, JM, Duncan, NM, Marin, PJ, Brown, LE, Loenneke, JP, Wilson, SMC, Jo, E, Lowery, RP, and Ugrinowitsch, C. Meta-analysis of postactivation potentiation and power: Effects of conditioning activity, volume, gender, rest periods, and training status. J Strength Cond Res 27(3): 854–859, 2013—There is no clear agreement regarding the ideal combination of factors needed to optimize postactivation potentiation (PAP) after a conditioning activity. Therefore, a meta-analysis was conducted to evaluate the effects of training status, volume, rest period length, conditioning activity, and gender on power augmentation due to PAP. A total of 141 effect sizes (ESs) for muscular power were obtained from a total of 32 primary studies, which met our criteria of investigating the effects of a heavy preconditioning activity on power in randomized human trials. The mean overall ES for muscle power was 0.38 after a conditioning activity (p < 0.05). Significant differences were found between moderate intensity (60–84%) 1.06 and heavy intensity (>85%) 0.31 (p < 0.05). There were overall significant differences found between single sets 0.24 and multiple sets 0.66 (p < 0.05). Rest periods of 7–10 minutes (0.7) after a conditioning activity resulted in greater ES than 3–7 minutes (0.54), which was greater than rest periods of >10 minutes (0.02) (p < 0.05). Significant differences were found between untrained 0.14 and athletes 0.81 and between trained 0.29 and athletes. The primary findings of this study were that a conditioning activity augmented power output, and these effects increased with training experience, but did not differ significantly between genders. Moreover, potentiation was optimal after multiple (vs. single) sets, performed at moderate intensities, and using moderate rest periods lengths (7–10 minutes).

Comparative absorption of curcumin formulations

BackgroundThe potential health benefits of curcumin are limited by its poor solubility, low absorption from the gut, rapid metabolism and rapid systemic elimination. The purpose of this study was the comparative measurement of the increases in levels of curcuminoids (curcumin, demethoxycurcumin, bisdemethoxycurcumin) and the metabolite tetrahydrocurcumin after oral administration of three different curcumin formulations in comparison to unformulated standard.MethodsThe relative absorption of a curcumin phytosome formulation (CP), a formulation with volatile oils of turmeric rhizome (CTR) and a formulation of curcumin with a combination of hydrophilic carrier, cellulosic derivatives and natural antioxidants (CHC) in comparison to a standardized curcumin mixture (CS) was investigated in a randomized, double-blind, crossover human study in healthy volunteers. Samples were analyzed by HPLC-MS/MS.ResultsTotal curcuminoids appearance in the blood was 1.3-fold higher for CTR and 7.9-fold higher for CP in comparison to unformulated CS. CHC showed a 45.9-fold higher absorption over CS and significantly improved absorption over CP (5.8-fold) and CTR (34.9-fold, all p < 0.001).ConclusionA formulation of curcumin with a combination of hydrophilic carrier, cellulosic derivatives and natural antioxidants significantly increases curcuminoid appearance in the blood in comparison to unformulated standard curcumin CS, CTR and CP.

Muscular adaptations in low- versus high-load resistance training: A meta-analysis

Abstract There has been much debate as to optimal loading strategies for maximising the adaptive response to resistance exercise. The purpose of this paper therefore was to conduct a meta-analysis of randomised controlled trials to compare the effects of low-load (≤60% 1 repetition maximum [RM]) versus high-load (≥65% 1 RM) training in enhancing post-exercise muscular adaptations. The strength analysis comprised 251 subjects and 32 effect sizes (ESs), nested within 20 treatment groups and 9 studies. The hypertrophy analysis comprised 191 subjects and 34 ESs, nested with 17 treatment groups and 8 studies. There was a trend for strength outcomes to be greater with high loads compared to low loads (difference = 1.07 ± 0.60; CI: −0.18, 2.32; p = 0.09). The mean ES for low loads was 1.23 ± 0.43 (CI: 0.32, 2.13). The mean ES for high loads was 2.30 ± 0.43 (CI: 1.41, 3.19). There was a trend for hypertrophy outcomes to be greater with high loads compared to low loads (difference = 0.43 ± 0.24; CI: −0.05, 0.92; p = 0.076). The mean ES for low loads was 0.39 ± 0.17 (CI: 0.05, 0.73). The mean ES for high loads was 0.82 ± 0.17 (CI: 0.49, 1.16). In conclusion, training with loads ≤50% 1 RM was found to promote substantial increases in muscle strength and hypertrophy in untrained individuals, but a trend was noted for superiority of heavy loading with respect to these outcome measures with null findings likely attributed to a relatively small number of studies on the topic.

β-Hydroxy-β-methylbutyrate free acid reduces markers of exercise-induced muscle damage and improves recovery in resistance-trained men.

The purpose of the present study was to determine the effects of short-term supplementation with the free acid form of b-hydroxyb-methylbutyrate (HMB-FA) on indices of muscle damage, protein breakdown, recovery and hormone status following a high-volume resistance training session in trained athletes. A total of twenty resistance-trained males were recruited to participate in a high-volume resistance training session centred on full squats, bench presses and dead lifts. Subjects were randomly assigned to receive either 3 g/d of HMB-FA or a placebo. Immediately before the exercise session and 48 h post-exercise, serum creatine kinase (CK), urinary 3-methylhistadine (3-MH), testosterone, cortisol and perceived recovery status (PRS) scale measurements were taken. The results showed that CK increased to a greater extent in the placebo (329%) than in the HMB-FA group (104%) (P¼0·004, d ¼ 1·6). There was also a significant change for PRS, which decreased to a greater extent in the placebo (9·1 (SEM 0·4) to 4·6 (SEM 0·5)) than in the HMB-FA group (9·1 (SEM 0·3) to 6·3 (SEM 0·3)) (P¼0·005, d ¼ 20·48). Muscle protein breakdown, measured by 3-MH analysis, numerically decreased with HMB-FA supplementation and approached significance (P¼0·08, d ¼ 0·12). There were no acute changes in plasma total or free testosterone, cortisol or C-reactive protein. In conclusion, these results suggest that an HMB-FA supplement given to trained athletes before exercise can blunt increases in muscle damage and prevent declines in perceived readiness to train following a high-volume, muscle-damaging resistance-training session.

PRACTICAL BLOOD FLOW RESTRICTION TRAINING INCREASES ACUTE DETERMINANTS OF HYPERTROPHY WITHOUT INCREASING INDICES OF MUSCLE DAMAGE

Abstract Wilson, JM, Lowery, RP, Joy, JM, Loenneke, JP, and Naimo, MA. Practical blood flow restriction training increases acute determinants of hypertrophy without increasing indices of muscle damage. J Strength Cond Res 27(11): 3068–3075, 2013—Vascular blood flow restriction (BFR) training stimulates muscle hypertrophy by increasing muscle activation and muscle swelling. Previous studies used expensive pneumatic cuffs, which may not be practical for regular use. The aim was to investigate the acute effects of low-intensity practical BFR (LI-pBFR) on muscle activation, muscle swelling, and damage. Twelve trained male participants completed a 30-, 15-, 15-, 15-repetition scheme at 30% of their leg press 1-repetition maximum under control and LI-BFR conditions. Under the LI-BFR trial, knee wraps were applied to the thighs at a pressure that resulted in venous, not arterial, occlusion. In the control trial, wraps were applied with zero pressure. Ultrasound-determined muscle thickness was recorded at baseline; 0 minutes post with wraps; 0, 5, and 10 minutes post without wraps. Muscle activation was recorded during warm-ups and on the final set of 15 repetitions. Indices of muscle damage (soreness, power, and muscle swelling) were also recorded. There was a condition by time effect for muscle thickness (p < 0.0001, effect size [ES] = 0.5), in which muscle thickness increased in the LI-pBFR condition 0 minutes post with wraps and through 5 minutes post without wraps. No changes occurred in the control. There was a condition by time effect for muscle activation (p < 0.05, ES = 0.2). The LI-pBFR had greater activation than the control did. There were no condition by time effects on indices of muscle damage. Our data indicate that practical BFR significantly increases muscle activation and muscle thickness without increasing indices of damage.

The Effects of Potentiating Stimuli Intensity Under Varying Rest Periods on Vertical Jump Performance and Power

Abstract Lowery, RP, Duncan, NM, Loenneke, JP, Sikorski, EM, Naimo, MA, Brown, LE, Wilson, FG, and Wilson, JM. The effects of potentiating stimuli intensity under varying rest periods on vertical jump performance and power. J Strength Cond Res 26(12): 3320–3325, 2012—Previous research has demonstrated that post-activation potentiation (PAP) increases in an intensity-dependent manner. However, these studies did not control for volume loads. The purpose of this study was to investigate the effects of varying intensities and rest period lengths, while controlling for volume load, on vertical jump (VJ) performance. Thirteen men, aged 21 ± 3 years with an average relative full squat of 1.7 ± 2 times their body weight, were recruited for this study. Participants were assigned to 3 different experimental sessions that required them to perform the back squat at 56% (low intensity), 70% (moderate intensity), and 93% (high intensity) of their 1 repetition maximums. Vertical jump height and power were recorded at 0, 2, 4, 8, and 12 minutes after squat. There was a significant condition by time interaction for VJ height and power, in which both variables did not change in the low-intensity condition, whereas decreasing immediately after squat for both the moderate- and high-intensity conditions. In the moderate- and high-intensity conditions, VJ height and power increased and peaked at minute 4 and returned to baseline by minutes 8 and 12. These results indicate that when controlling for total work, jump performance and power are enhanced similarly by moderate and high squat intensities. However, high-intensity workloads may prolong the duration of PAP. Therefore, athletes may use moderate- and high-intensity loads during warm-ups to improve jump performance and power.

A Ketogenic Diet in Rodents Elicits Improved Mitochondrial Adaptations in Response to Resistance Exercise Training Compared to an Isocaloric Western Diet

Purpose: Ketogenic diets (KD) can facilitate weight loss, but their effects on skeletal muscle remain equivocal. In this experiment we investigated the effects of two diets on skeletal muscle mitochondrial coupling, mitochondrial complex activity, markers of oxidative stress, and gene expression in sedentary and resistance exercised rats. Methods: Male Sprague-Dawley rats (9–10 weeks of age, 300–325 g) were fed isocaloric amounts of either a KD (17 g/day, 5.2 kcal/g, 20.2% protein, 10.3% CHO, 69.5% fat, n = 16) or a Western diet (WD) (20 g/day, 4.5 kcal/g, 15.2% protein, 42.7% CHO, 42.0% fat, n = 16) for 6 weeks. During these 6 weeks animals were either sedentary (SED, n = 8 per diet group) or voluntarily exercised using resistance-loaded running wheels (EXE, n = 8 per diet group). Gastrocnemius was excised and used for mitochondrial isolation and biochemical analyses. Results: In the presence of a complex II substrate, the respiratory control ratio (RCR) of isolated gastrocnemius mitochondria was higher (p < 0.05) in animals fed the KD compared to animals fed the WD. Complex I and IV enzyme activity was higher (p < 0.05) in EXE animals regardless of diet. SOD2 protein levels and GLUT4 and PGC1α mRNA expression were higher (p < 0.05) in EXE animals regardless of diet. Conclusion: Our data indicate that skeletal muscle mitochondrial coupling of complex II substrates is more efficient in chronically resistance trained rodents fed a KD. These findings may provide merit for further investigation, perhaps on humans.

Practical blood flow restriction training increases muscle hypertrophy during a periodized resistance training programme

Resistance training in combination with practical blood flow restriction (pBFR) is thought to stimulate muscle hypertrophy by increasing muscle activation and muscle swelling. Most previous studies used the KAATSU device; however, little long‐term research has been completed using pBFR.

Effects of oral adenosine-5'-triphosphate supplementation on athletic performance, skeletal muscle hypertrophy and recovery in resistance-trained men

BackgroundCurrently, there is a lack of studies examining the effects of adenosine-5′-triphosphate (ATP) supplementation utilizing a long-term, periodized resistance-training program (RT) in resistance-trained populations. Therefore, we investigated the effects of 12 weeks of 400 mg per day of oral ATP on muscular adaptations in trained individuals. We also sought to determine the effects of ATP on muscle protein breakdown, cortisol, and performance during an overreaching cycle.MethodsThe study was a 3-phase randomized, double-blind, and placebo- and diet-controlled intervention. Phase 1 was a periodized resistance-training program. Phase 2 consisted of a two week overreaching cycle in which volume and frequency were increased followed by a 2-week taper (Phase 3). Muscle mass, strength, and power were examined at weeks 0, 4, 8, and 12 to assess the chronic effects of ATP; assessment performance variables also occurred at the end of weeks 9 and 10, corresponding to the mid and endpoints of the overreaching cycle.ResultsThere were time (p < 0.001), and group x time effects for increased total body strength (+55.3 ± 6.0 kg ATP vs. + 22.4 ± 7.1 kg placebo, p < 0.001); increased vertical jump power (+ 796 ± 75 ATP vs. 614 ± 52 watts placebo, p < 0.001); and greater ultrasound determined muscle thickness (+4.9 ± 1.0 ATP vs. (2.5 ± 0.6 mm placebo, p < 0.02) with ATP supplementation. During the overreaching cycle, there were group x time effects for strength and power, which decreased to a greater extent in the placebo group. Protein breakdown was also lower in the ATP group.ConclusionsOur results suggest oral ATP supplementation may enhance muscular adaptations following 12-weeks of resistance training, and prevent decrements in performance following overreaching. No statistically or clinically significant changes in blood chemistry or hematology were observed.Trial registrationClinicalTrials.gov NCT01508338

Changes in perceived recovery status scale following high-volume muscle damaging resistance exercise.

Abstract Sikorski, EM, Wilson, JM, Lowery, RP, Joy, JM, Laurent, CM, Wilson, SM-C, Hesson, D, Naimo, MA, Averbuch, B, and Gilchrist, P. Changes in perceived recovery status scale following high-volume muscle damaging resistance Exercise. J Strength Cond Res 27(8): 2079–2085, 2013—Currently no research has investigated the relationship between muscle damage, hormonal status, and perceived recovery scale (PRS). Therefore, the purpose of this study was to determine the effects of a high-volume training session on PRS and to determine the relationship between levels of testosterone, cortisol, and creatine kinase (CK) and PRS. Thirty-five trained subjects (21.3 ± 1.9 years) were recruited. All subjects participated in a high-volume resistance training session consisting of 3 sets of full squats, bench press, deadlifts, pullups, dips, bent over rows, shoulder press, and barbell curls and extensions. Pre-PRS and post-PRS measurements (0–10), soreness, CK, cortisol, and testosterone were measured before and 48 hours after training. Perceived recovery scale declined from 8.6 ± 2.3 to 4.2 ± 1.85 (p < 0.05). Leg, chest, and arm soreness increased from pre- to postexercise. Creatine kinase significantly increased from pre- to postworkout (189.4 ± 100.2 to 512 ± 222.7 U/L). Cortisol, testosterone, and free testosterone did not change. There was an inverse relationship between CK and PRS (r2 = 0.58, p < 0.05). When muscle damage was low before training, cortisol and free and total testosterone were not correlated to PRS. However, when damage peaked at 48 hours postexercise, free, but not total, testosterone showed a low direct relationship with PRS (r2 = 0.2, p < 0.05). High-volume resistance exercise lowers PRS scores. These changes are partly explained by a rise in serum indices of muscle damage. Moreover, free testosterone seems to have a positive relationship with PRS.