The study aims to examine the effect of a New Zealand blackcurrant (NZBC) supplement on markers of muscle damage and recovery following strenuous resistance exercise. The investigation will compare responses between an experimental (NZBC capsule, 300 mg/day) and placebo (PLA capsule, 300 mg sugar) group. Participants will attend a screening session where they will consent to the study, complete a pre-activity medical questionnaire and have their height, weight and resting blood pressure measured. If the participants meet the inclusion criteria they will perform a familarisation session on the muscle strength assessment. Participants will be randomized to NZBC or placebo groups, and consume one capsule in the morning (between 6-10 am) for 12 days. This is a double-blinded study, which means that the participant and the study team will not know which group the participants are assigned to until the study is over. On day 8 participants will perform a strenuous bout of upper body resistance exercise on the isokinetic dynamometer (exercise device). Muscle strength and soreness, arm circumference, and elbow range of motion will be measured, and a fasted blood sample will be collected, before and 24, 48, 72 \& 96 hours after the muscle fatigue protocol (on days 9, 10, 11 \& 12). A marker of muscle damage (creatine kinase \[CK\] concentration) will be measured in the blood samples. Participants will also be asked to complete a 6-day dietary record, beginning on day 7 and ending on the final day of testing (day 12).
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
DOUBLE
Enrollment
27
NZBC capsules containing anthocyanin-rich blackcurrant extract
Placebo capsules containing microcrystalline cellulose
Surrey Human Performance Institute
Guildford, Surrey, United Kingdom
Change from baseline in creatine kinase (CK) concentration at 72 hours post-exercise
Serum biomarker for muscle damage
Time frame: At baseline (pre-exercise) and 72 hours post-exercise.
Change from baseline in creatine kinase (CK) concentration at 96 hours post-exercise
Serum biomarker for muscle damage
Time frame: At baseline (pre-exercise) and 96 hours post-exercise..
Change in maximum voluntary contraction (MVC) from baseline to 96 hours post-exercise
Muscle function measure; maximal voluntary isometric contraction (torque, Nm) performed on isokinetic dynamometer
Time frame: At baseline (pre-exercise) and post-exercise time points (at 0, 24, 48, 72 and 96 hours respectively).
Change in rating of Delayed Onset of Muscle Soreness (DOMS) from baseline to 96 hours post-exercise
Self-reported perception of muscle soreness using a visual analogue scale (VAS), from 'no soreness' \[0 mm\] on the left anchor point to 'extremely sore' \[100 mm\] on the right
Time frame: At baseline (pre-exercise) and post-exercise time points (at 24, 48, 72 and 96 hours respectively).
Change in joint range of motion (ROM) from baseline to 96 hours post-exercise
Elbow ROM measured using a goniometer
Time frame: At baseline (pre-exercise) and post-exercise time points (at 24, 48, 72 and 96 hours respectively).
Change in mid arm circumference (MAC) from baseline to 96 hours post-exercise
Mid-upper arm circumference measured at the midpoint of the distance from the acromion process (acromiale) to the olecranon process (radiale).
Time frame: At baseline (pre-exercise) and post-exercise time points (at 24, 48, 72 and 96 hours respectively).
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