RESUMO
BACKGROUND: Palmitoylethanolamide (PEA) has analgesic/anti-inflammatory properties that may be a suitable alternative to over-the-counter (OTC) non-steroidal analgesics/anti-inflammatories. While OTC pain medications can impair strength training adaptations, the mechanism of action of PEA is distinct from these and it may not negatively affect skeletal muscle adaptations to strength training. METHODS: The primary aim of this study was to investigate the effects of daily PEA supplementation (350 mg Levagen + equivalent to 300 mg PEA) combined with 8-weeks of resistance training on lean body mass with secondary aims addressing strength, power, sleep, and wellbeing compared to placebo (PLA) in young, healthy, active adults. In a randomized, controlled, double-blinded trial, 52 untrained, recreationally active participants aged 18-35 y were allocated to either the PEA or PLA groups. Participants consumed either 2 × 175 mg Levagen + PEA or identically matched maltodextrin capsules during an 8-week period of whole-body resistance training. This trial assessed the pre- to post- changes in total and regional lean body mass, muscular strength (1-RM bench, isometric mid-thigh pull), muscular power [countermovement jump (CMJ), bench throw], pain associated with exercise training, sleep, and wellbeing compared with the PEA or PLA condition. RESULTS: 48 Participants were included in the final intention to treat (ITT) analysis and we also conducted per protocol (PP) analysis (n = 42). There were no significant between-group differences for total or regional lean muscle mass post-intervention. There was a significantly higher jump height (CMJ) at week 10 in the PEA group compared to the PLA (Adjusted mean difference [95% CI] p-value; ITT: - 2.94 cm [- 5.15, - 0.74] p = 0.010; PP: - 2.93 cm [- 5.31, - 0.55] p = 0.017). The PLA group had higher 1-RM bench press post-intervention compared with the PEA group (ITT: 2.24 kg [0.12, 4.37] p = 0.039; PP: 2.73 kg [0.40, 5.06] p = 0.023). No significant treatment effects were noted for any of the other outcomes. CONCLUSION: PEA supplementation, when combined with 8 weeks of strength training, did not impair lean mass gains and it resulted in significantly higher dynamic lower-body power when compared with the PLA condition. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry (ANZCTR: ACTRN12621001726842p).
RESUMO
BACKGROUND: Non-steroidal anti-inflammatory drugs (NSAIDs) and analgesics are used frequently by athletes either prophylactically for the prevention of pain, or to accelerate recovery following an injury. However, these types of pain management strategies have been shown to inhibit signalling pathways (e.g., cyclooxygenase-2) that may hinder muscular adaptations such as hypertrophy and strength. Nutraceuticals such as palmitoylethanolamide (PEA) have analgesic properties that act via different mechanisms to NSAIDS/analgesics. Furthermore, PEA has been shown to have a positive effect on sleep and may contribute positively to muscle hypertrophy via PKB activation. Although PEA has not been widely studied in the athletic or recreationally active population, it may provide an alternative solution for pain management if it is found not to interfere with, or enhance training adaptations. Therefore, the study aim is to investigate the effects of daily PEA supplementation (Levagen + ®) with resistance training on lean body mass, strength, power and physical performance and outcomes of recovery (e.g., sleep) compared to placebo. METHODS: This double-blind, randomised controlled study will take place over an 11-week period (including 8-weeks of progressive resistance training). Participants for this study will be 18-35 years old, healthy active adults that are not resistance trained. Participants will attend a familiarisation (week 0), pre-testing (week 1) and final-testing (week 11). At the pre-testing and final-testing weeks, total lean body mass (dual-energy X-ray absorptiometry; DXA), total mid-thigh cross sectional area (pQCT), maximal muscular strength (1 repetition maximum bench press, isometric mid-thigh pull) and power (countermovement jump and bench throw) will be assessed. Additionally, circulating inflammatory cytokines and anabolic hormones, sleep quality and quantity (ActiGraph), pain and subjective wellbeing (questionnaires) will also be examined. DISCUSSION: This study is designed to investigate the effects that PEA may have on pre-to post intervention changes in total body and regional lean muscle mass, strength, power, sleep, subjective wellbeing, and pain associated with resistance training and menstruation compared with the placebo condition. Unlike other NSAIDs and analgesics, which may inhibit muscle protein synthesis and training adaptations, PEA which provides analgesia via alternative mechanisms may provide an alternative pain management solution. It is therefore important to determine if this analgesic compound interferes with or enhances training adaptations so that athletes and active individuals can make an informed decision on their pain management strategies. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry (ANZCTR: ACTRN12621001726842p).