Effects of Protein and NAC Co-ingestion on Skeletal Muscle Recovery

Официальное название

Effects of Whey Protein and N-acetylcysteine Co-ingestion on Skeletal Muscle Recovery Following Exercise-induced Muscle Damage.

Обзор

Previous evidence suggests that though N-acetylcysteine (NAC) supplementation following eccentric exercise-induced muscle damage disrupts the skeletal muscle's repair and remodelling process at 8 days of recovery, it attenuates substantially the decline of skeletal muscle performance during the first 48 hours of recovery. The enhanced performance capacity during the first phase of recovery in response to NAC supplementation might be attributed to the altered redox status in skeletal muscle as a consequence of the NAC-mediated elevation of reduced glutathione (GSH) levels. The rise in GSH results in a redox-dependent attenuation of immune cell mobilisation and reduction of oxidative stress response, leading to a blunted rise of muscle damage and inflammatory markers during the first 2-3 days of recovery. However, following exercise-induced muscle damage, protein synthesis increases in skeletal muscle over the next 24-48 hours to support its repair process, and thus protein supplementation might accelerate the recovery process by enhancing the protein synthetic response. Therefore, the present study aims at investigating for first time the combined effect of NAC and whey protein supplementation on the short-term (during the first 72 hours) recovery process of skeletal muscle following damaging exercise (eccentric exercise) and compared it with the well-documented efficacy of NAC supplementation. The results of this study might be particularly useful for athletes, such as those in soccer and basketball, that participate in 3 games or intense training sessions during the same macrocycle with only 48-72 hours of recovery in-between.

Подробное описание

Participants will initially undergo baseline testing including assessment of their (i) anthropometrics, (ii) body composition via DXA, (iii) habitual physical activity level via accelerometry, (iv) resting metabolic rate via indirect calorimetry, (v) daily dietary intake via 7-day dietary recalls and (vi) cardiorespiratory fitness using a treadmill ramp test. After baseline testing, participants will be assigned to (a) a Placebo, (b) a N-acetylcysteine (NAC) or (c) a N-acetylcysteine + Whey protein (PRoNAC) group, in a randomized, double-blind, placebo-controlled, parallel group, repeated measures design. In all groups, participants will execute an eccentric exercise protocol on an isokinetic dynamometer consisted of 150 eccentric muscle contractions. Before exercise as well as at 1-, 2-, 3-, 24-, 48- and 72-hours post-exercise they will undergo assessment of their maximal voluntary isometric peal torque, maximal countermovement jump height and muscle soreness level. In addition, blood sample will be drawn before exercise and at 24-, 48- and 72-hours post-exercise for the determination of myoglobin concentration, reduced (GSH) and oxidized (GSSG) glutathione content, protein carbonyl formation and catalase activity.

Throughout the 4-day experimental period (Day 1: exercise day, Days 2, 3 and 4: 24-, 48- and 72-hours post-exercise, respectively) participants will receive daily, 3 doses from the respective supplement as follows: the 1st dose at mid-morning (between breakfast and lunch), the 2nd dose at mid-afternoon (post-exercise on day 1 and between lunch and dinner on days 2-4) and the 3rd dose before sleep. In Placebo group, participants will be supplemented with 0.31 gr of maltodextrin per kg of body weight in the first two servings (at mid-morning and mid-afternoon supplements) and with 0.49 gr of maltodextrin per kg of body weight in the pre-sleep serving (1.1 gr maltodextrin/kg BW/day). In NAC group, participants will be supplemented with 13.33 mg of N-acetylcysteine per kg of body weight per serving (40 mg NAC/kg BW/day). In PRoNAC group participants will be supplemented with 0.31 gr of whey protein and 13.33 mg of N-acetylcysteine per kg of body weight in the first two servings (at mid-morning and mid-afternoon supplements) and with 0.49 gr of whey protein and 13.33 mg of N-acetylcysteine per kg of body weight in the pre-sleep serving (1.1 gr Whey protein + 40 mg NAC /kg BW/day).

Вмешательства

• Пищевая добавка Placebo
  Participants will receive three servings of carbohydrate per day during the 4-day experimental period. In specific, they will be supplemented with 0.31 gr of maltodextrin per kg of body weight in the first two servings (at mid-morning and mid-afternoon supplements) and with 0.49 gr of maltodextrin per kg of body weight in the pre-sleep serving (1.1 gr maltodextrin/kg BW/day).
• Пищевая добавка NAC
  Participants will receive three servings of N-acetylcysteine per day during the 4-day experimental period. In specific, they will be supplemented with 13.33 mg of N-acetylcysteine per kg of body weight per serving (40 mg NAC/kg BW/day).
• Пищевая добавка NAC + Whey Protein
  Participants will receive three servings of N-acetylcysteine + whey protein per day during the 4-day experimental period. In specific, they will be supplemented with 0.31 gr of whey protein and 13.33 mg of N-acetylcysteine per kg of body weight in the first two servings (at mid-morning and mid-afternoon supplements) and with 0.49 gr of whey protein and 13.33 mg of N-acetylcysteine per kg of body weight in the pre-sleep serving (1.1 gr Whey protein + 40 mg NAC /kg BW/day).

Первичные конечные точки

• Change in maximal voluntary isometric muscle contraction. [Срок оценки: Before exercise and at 1-, 2-, 3-, 24-, 48- and 72-hours post-exercise.]
• Change in countermovement jump height. [Срок оценки: Before exercise and at 1-, 2-, 3-, 24-, 48- and 72-hours post-exercise.]
• Change in delayed onset of muscle soreness (DOMS) [Срок оценки: Before exercise and at 1-, 2-, 3-, 24-, 48- and 72-hours post-exercise.]
• Change in reduced glutathione content. [Срок оценки: Before exercise and at 24-, 48- and 72-hours post-exercise.]
• Change in oxidized glutathione content. [Срок оценки: Before exercise and at 24-, 48- and 72-hours post-exercise.]
• Change in catalase activity. [Срок оценки: Before exercise and at 24-, 48- and 72-hours post-exercise.]
• Change in protein carbonyl concentration [Срок оценки: Before exercise and at 24-, 48- and 72-hours post-exercise.]
• Change in myoglobin concentration in blood. [Срок оценки: Before exercise and at 24-, 48- and 72-hours post-exercise.]

Вторичные конечные точки (8)

• Participants' lean body mass [Срок оценки: At baseline.]
• Participants' daily physical activity-related energy expenditure. [Срок оценки: At baseline.]
• Participants daily dietary intake. [Срок оценки: At baseline.]
• Participants' resting metabolic rate. [Срок оценки: At baseline.]
• Participants' cardiorespiratory fitness status. [Срок оценки: At baseline.]
• Participants' fat free mass. [Срок оценки: At baseline.]
• Participants' fat mass. [Срок оценки: At baseline.]
• Participants' body fat percent. [Срок оценки: At baseline.]

Критерии участия

Критерии включения

• Free of asthma, kidney disease, bleeding disorders, peptic ulcers.
• Free of musculoskeletal injuries and limitations.
• Abstain from dietary energy restriction.
• Do not use medication such as anti-inflammatory drugs, antibiotics, antihypertensive drugs or anticoagulants.
• Do not use dietary supplements such as protein, carbohydrate, antioxidants, vitamins etc.
• Free of N-acetylcysteine intolerance.
• Non-smokers.
• Abstain from alcohol throughout the study.

Критерии исключения

• Presence of asthma, kidney disease, bleeding disorders, peptic ulcers.
• Musculoskeletal injuries and limitations.
• Dietary energy restriction.
• Use of anti-inflammatory drugs, antibiotics, antihypertensive drugs or anticoagulants.
• Use of dietary supplements such as protein, carbohydrate, antioxidants, vitamins etc.
• N-acetylcysteine intolerance.
• Smoking.
• Alcohol consumption during the study.

Критерии приведены из реестра в оригинале (на английском). Окончательную оценку соответствия проводит исследовательский центр.

Здоровые добровольцы: Да

Дизайн исследования

Распределение

Рандомизированное

Модель

Параллельные группы

Маскирование

Тройное слепое

Основная цель

Лечение

Центры проведения

Греция · 1 центр

• Department of Physical Education and Sport Science, University of Thessaly — Trikala

Идентификаторы

NCT: NCT06367413 · UTH-PRoNAC Study

Первоисточники (государственные реестры)

• ClinicalTrials.gov (NIH, США)

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