Acute Consumption of Varied Doses of Cocoa Flavanols Does Not Influence Exercise-Induced Muscle Damage

Abstract

<jats:p>Polyphenol consumption has become a popular method of trying to temper muscle damage. Cocoa flavanols (CF) have attracted attention due to their high polyphenol content and palatability. As such, this study will investigate whether an acute dose of CF can aid recovery following exercise-induced muscle damage. The study was a laboratory-based, randomized, single-blind, nutrient-controlled trial involving 23 participants (13 females and 10 males). Participants were randomized into either control ∼0 mg CF (<jats:italic>n</jats:italic> = 8, four females); high dose of 830 mg CF (CF<jats:sub>830</jats:sub>, <jats:italic>n</jats:italic> = 8, five females); or supra dose of 1,245 mg CF (CF<jats:sub>1245</jats:sub>, <jats:italic>n</jats:italic> = 7, four females). The exercise-induced muscle damage protocol consisted of five sets of 10 maximal concentric/eccentric hamstring curls and immediately consumed their assigned drink following completion. To measure muscle recovery, maximal voluntary isometric contraction (MVIC) of the knee flexors at 60° and 30°, a visual analog scale (VAS), and lower-extremity function scale were taken at baseline, immediately, 24-, 48-, and 72-hr postexercise-induced muscle damage. There was a main effect for time for all variables (<jats:italic>p</jats:italic> &lt; .05). However, no significant differences were observed between groups for all measures (<jats:italic>p</jats:italic> ≥ .17). At 48 hr, there were large effect sizes between control and CF<jats:sub>1245</jats:sub> for MVIC60 (<jats:italic>p</jats:italic> = .17, <jats:italic>d</jats:italic> = 0.8); MVIC30 (<jats:italic>p</jats:italic> = .26, <jats:italic>d</jats:italic> = 0.8); MVIC30 percentage change (<jats:italic>p</jats:italic> = .24 <jats:italic>d</jats:italic> = 0.9); and visual analog scale (<jats:italic>p</jats:italic> = .25, <jats:italic>d</jats:italic> = 0.9). As no significant differences were observed following the consumption of CF, there is reason to believe that CF offer no benefit for muscle recovery when ingested acutely.</jats:p>

The effects of cocoa flavanols on indices of muscle recovery and exercise performance: a narrative review

“…Muscle function is negatively impacted by EIMD, with reductions in muscle force and power capacity evident for several days following strenuous exercise. However, based on the current evidence it seems that CF supplementation has minimal, if not any, impact on maximal voluntary contraction (MVC; as measured using peak torque) with no effect observed on knee extensor [ 48 , 49 , 79 ] or knee flexor strength recovery [ 80 ]. Interestingly however, Corr, Field [ 80 ] found that at 24 and 48 h post-exercise there were large effect sizes following an acute high dose of 1245 mg CF compared to the control for MVC at 30 degrees and MVC percentage change at 60 and 30 degrees, although no significant differences were observed.…”

“…However, based on the current evidence it seems that CF supplementation has minimal, if not any, impact on maximal voluntary contraction (MVC; as measured using peak torque) with no effect observed on knee extensor [ 48 , 49 , 79 ] or knee flexor strength recovery [ 80 ]. Interestingly however, Corr, Field [ 80 ] found that at 24 and 48 h post-exercise there were large effect sizes following an acute high dose of 1245 mg CF compared to the control for MVC at 30 degrees and MVC percentage change at 60 and 30 degrees, although no significant differences were observed. Therefore, it is feasible that the dose of 1245 mg CF has the potential to be effective but may require repeated dosing throughout the recovery period instead of a singular acute dose to be truly efficacious.…”

“…Therefore, it is feasible that the dose of 1245 mg CF has the potential to be effective but may require repeated dosing throughout the recovery period instead of a singular acute dose to be truly efficacious. Currently, for (poly)phenols it has been suggested that > three days of supplementation above 1000 mg may be required to observe an ergogenic benefit [ 81 ], however no CF research has been performed fulfilling that criteria, with only one study using a dose above 1000 mg of CF [ 80 ].…”

“…It is noteworthy that only Morgan, Wollman [ 42 ] and Corr, Field [ 80 ] observed notable muscle damage based on decrements in muscle function across groups [ 82 ]. To best understand the mechanisms behind CFs role in muscle damage recovery, it would be prudent to ensure symptoms of EIMD such as a decrease in muscle function are pronounced.…”

“…Measures of perceived soreness are predominantly subjective in nature, typically measured using validated scales to quantify subjective pain, soreness and discomfort such as a visual analogue scale (VAS) [ 83 ] or lower extremity functional scale (LEFS) [ 84 ]. As muscular soreness is ubiquitous with EIMD, most studies investigating muscle damage utilised these measures of perceived soreness as a way of tracking recovery [ 48 , 49 , 79 , 80 ]. Peschek, Pritchett [ 79 ] administered two doses of 350 mg CF post EIMD which were separated by two hours and found no effect of treatment on VAS or LEFS scores.…”