Almond Consumption Modestly Improves Pain Ratings, Muscle Force Production, and Biochemical Markers of Muscle Damage Following Downhill Running in Mildly Overweight, Middle-Aged Adults: A Randomized, Crossover Trial

Abstract

Background: Almonds promote cardiometabolic health benefits; however, the ergogenic effect of almond supplementation on exercise recovery is less explored.

Objectives: We evaluated the impacts of raw, shelled, almonds on pain, muscle force production, and biochemical indices of muscle damage and inflammation during recovery from eccentrically biased exercise.

Methods: Using a randomized, crossover design, 26 healthy adults (37 ± 6 y) ran downhill (-10%) for 30 min at a heart rate corresponding to 65%-70% of maximal oxygen consumption followed by 3-d recovery periods after 8-wk adaptations to either ALMOND (2 oz/d) or isocaloric pretzel (CONTROL) feedings. Volunteers consumed the study food immediately following the run and each day during recovery. Fasted blood samples were collected, and pain and muscle function were tested before the downhill run and over 72 h of recovery.

Results: Downhill running elicited moderate muscle damage (Time: P < 0.001; η² = 0.395) with creatine kinase (CK) peaking after 24 h (CONTROL: Δ + 180% from baseline compared with ALMOND: Δ + 171% from baseline). CK was reduced after 72 h in ALMOND (Δ - 50% from peak; P < 0.05) but not CONTROL (Δ - 33% from peak; P > 0.05). Maximal torque at 120°/s of flexion was greater (Trial: P = 0.004; η² = 0.315) in ALMOND compared with CONTROL at 24 h (Δ + 12% between trials; P < 0.05) and 72 h (Δ + 9% between trials; P < 0.05) timepoints. Pain during maximal contraction was lower (Trial: P < 0.026; η² = 0.225) in ALMOND compared with CONTROL after 24 h (Δ - 37% between trials; P < 0.05) and 48 h (Δ - 33% between trials; P < 0.05). No differences (P > 0.05) in vertical jump force, C-reactive protein concentrations, myoglobin concentrations, and total antioxidant capacity were observed between trials.

Conclusions: This study demonstrates that 2.0 oz/d of almonds modestly reduces pain, better maintains muscle strength, and reduces the CK response to eccentric-based exercise. This apparent effect of almond ingestion on exercise recovery has the potential to promote increased exercise adherence, which should be investigated in future studies.This trial was registered at the clinicaltrials.gov as NCT04787718.

Keywords: creatine kinase; human; nut; power; recovery; soreness; strength.

FIGURE 1

Flowchart of study design.

FIGURE 2

Changes in creatine kinase concentrations (units/L) over time across trials. ¹Black (control) and gray (almond) dots represent individual data points within the respective timepoint. ∗ indicates significant difference in change between timepoints during the control trial (P < 0.05). ∗∗ indicates significant difference in change between timepoints during the almond trial (P < 0.05).

FIGURE 3

Changes in myoglobin concentrations (ng/mL) over time across trials. ¹Black (control) and gray (almond) dots represent individual data points within the respective timepoint. ∗ indicates significant difference in change between timepoints during the control trial (P < 0.05). ∗∗ indicates significant difference in change between timepoints during the almond trial (P < 0.05). # indicates significant difference between trials at a respective timepoint (P < 0.05).

FIGURE 4

Changes in C-reactive protein concentrations (mg/L) over time across trials. ¹Black (control) and gray (almond) dots represent individual data points within the respective timepoint.

FIGURE 5

Changes in total antioxidant capacity (mM) over time across trials. ¹Black (control) and gray (almond) dots represent individual data points within the respective timepoint.