Effect of New Zealand Blackcurrant Extract on Isometric Contraction-Induced Fatigue and Recovery: Potential Muscle-Fiber Specific Effects

The Influence of Berry-Derived Polyphenol Supplementation on Exercise-Induced Oxidative Stress and Cardiovascular Health in Physically Active Individuals

Numerous studies have documented that high-intensity or prolonged exercise is associated with increased oxidative stress and modification of antioxidant status. Polyphenol-rich dietary supplements seem to be the compounds that can upregulate the endogenous antioxidant defense system and consequently prevent muscle damage, support recovery. As berry fruits are at the top of the list of the richest polyphenol food sources, supplements containing berries have become the subject of interest in the context of counteracting exercise-induced oxidative stress and the development of cardiovascular diseases. The purpose of this review is to summarize current knowledge on the effects of berry-derived polyphenol supplementation on exercise-induced oxidative stress and cardiovascular health in physically active individuals. Based on the available literature, blackcurrant supplementation, with its richest version being New Zealand blackcurrant extract, is the most commonly explored berry fruit, followed by chokeberries and blueberries. Although several studies have documented the significant and beneficial influence of berry-derived supplements on redox status and cardiovascular response, some inconsistencies remain. The presented findings should be interpreted with caution due the limited number of available studies, particularly with the participation of physically active individuals. Further research is needed to reveal more comprehensive and accurate data concerning the impact of berry-derived supplements on exercise-induced outcomes taking into account the type of supplement, time of administration, and dosage.

Individual Responses to Repeated Dosing with Anthocyanin-Rich New Zealand Blackcurrant Extract During High-Intensity Intermittent Treadmill Running in Active Males

Intake of New Zealand blackcurrant (NZBC) extract for 7 days has been shown to improve high-intensity intermittent running (HIIR) performance.

OBJECTIVES

We examined the repeat response of NZBC extract on HIIR performance.

METHODS

Sixteen active males (age: 23 ± 3 yrs, height: 179 ± 5 cm, mass: 79 ± 11 kg, V˙O2max: 55.3 ± 5 mL∙kg-1∙min-1, velocity at V˙O2max: 17.2 ± 0.8 km∙h-1, mean ± SD) participated. Familiarized subjects completed the HIIR test at individualized exercise intensities with stages consisting of six 19 s high-intensity running bouts interspersed by 15 s of low-intensity running and 1 min of inter-stage rest. The test was repeated at increasing speeds until exhaustion, under four conditions; two with a daily dose of 600 mg of NZBC extract (CurraNZ™, providing 210 mg anthocyanins) and two with a placebo, each over 7 days. The study used a double-blind, randomized, cross-over design with a wash-out period of at least 14 days.

RESULTS

For the cohort, there were no differences between the placebo and NZBC conditions for mean heart rate (p = 0.071), mean oxygen uptake (p = 0.713), and mean lactate (p = 0.121) at exhaustion for the HIIR. The NZBC extract increased the mean total running distance and mean high-intensity running distance by 7.9% and 8.0% compared to the placebo. With NZBC extract, 8 of the 16 participants (50%) enhanced in both trials beyond the smallest worthwhile change for total running distance (≥173 m) and high-intensity running distance (≥111 m). For repeated responders, total running distance and high-intensity running distance was increased by 16.7% (95% CI [11.0, 22.4%] and 16.6% (95% CI [11.0, 22.2%]. Three participants had enhanced running performance in one trial beyond the SWC, and five participants were considered non-responders.

CONCLUSIONS

This is the first study on the repeated response by an anthocyanin-rich supplement on high-intensity running performance. New Zealand blackcurrant extract can substantially enhance intermittent high-intensity running performance in consistent responders. Future work should examine dosing strategies of New Zealand blackcurrant, and whether a repeated response rate exceeding 50% can be attained. These findings suggest that NZBC extract could be beneficial for athletes participating in high-intensity team sports.

Berry Fruits and Their Improving Potential on Skeletal Muscle Health and Performance: A Systematic Review of the Evidence in Animal and in Human Studies

The well-established anti-inflammatory and antioxidant properties of red fruits leave room for a biological pathway of improved muscle health promoted by berries in the diet. Our objective was to systematically review the number of trials conducted on human and animal species around the relationship between a berry diet and muscle health outcomes. Two independent examiners conducted a search for studies that utilized keywords associated with muscle health outcomes and a berry-based diet in both human and animal trials, in accordance with the PRISMA statement guidelines. The literature was searched through six electronic databases until December 2023. Screening of 152 retrieved articles resulted in a final selection of 16 reports investigating the effect of exposure to a berry-based diet and skeletal muscle health outcomes. The study protocol was registered on PROSPERO (CRD42023479682). Among the selected studies, nine involved humans and seven animal models (rats and mice). Overall, most of the studies reported positive effects on performance or muscle health. Specifically, five studies investigated the possible effects of blackcurrant on active human subjects or athletes; three studies focused on blueberry and presented results on running performance (human sample) and muscle health (rat models). The rest of the studies involved raspberries (two studies, rat models), aronia (one study, rat models), elderberry (one study, rat models), and a mixed compound (one study, rat models). In conclusion, there is some early evidence that a berry-rich diet may increase performance or muscle health, but more research is needed to fully understand the underlying biological trajectories, and thus, no firm conclusions can yet be drawn.

CHINESE MEDICINAL BATH ON ATHLETES’ SPORT MUSCLE FATIGUE

ABSTRACT Introduction: The Fifth International Conference on Sports Biochemistry defines sports fatigue as the physiological process of dysfunction at a certain level or inability to maintain predetermined exercise intensity. When left untreated, it can cause adverse effects to the musculoskeletal system. Natural alternatives for controlling sports fatigue exist in Chinese culture, but scientific research is needed to determine the effectiveness of these treatments. Objective: This study aimed to verify the effect of traditional Chinese medicinal baths on athletes’ muscle fatigue. Methods: 100 athletes with exercise-induced muscle fatigue were randomly divided into two groups. The control group received ganglioside injection combined with therapeutic exercise protocols, while the experimental group received the medicinal bath based on traditional Chinese medicine. Tonus of adductors, ischiotibials, gastrocnemius, in addition to lower limb motor function, was evaluated. Results: The total effective rate (90.8%) of the observation group was higher than that of the control group (72.3%), and the difference was statistically significant (P<0.05). After treatment, adductor, hamstring, and gastrocnemius muscle tension in the observation group were lower than the control group (P<0.05). Gross motor function assessment score (GMFM-88), Berg Balance Scale (BBS), 10m walking speed on a 20cm wide walkway (MWS) in the observation group were higher than those in the control group (P<0.05). Conclusion: Chinese herbal lavender lotion combined with suspension exercise can effectively improve the body's muscle strength after exercises, accelerate the recovery of muscle strength, and significantly reduce exercise-induced muscle fatigue. Evidence Level II; Therapeutic Studies - Investigating the result.

Effect of New Zealand Blackcurrant Extract on Force Steadiness of the Quadriceps Femoris Muscle during Sustained Submaximal Isometric Contraction

Intake of anthocyanin-rich New Zealand blackcurrant (NZBC) can alter physiological responses that enhance exercise performance. In two studies, we examined the effects of NZBC extract on force steadiness during a sustained submaximal isometric contraction of the quadriceps femoris muscle. With repeated measures designs, male participants in study one (n = 13) and study two (n = 19) performed a 120 s submaximal (30%) isometric contraction of the quadriceps femoris muscle following a 7-day intake of NZBC extract and placebo (study one) and following 0 (control), 1-, 4- and 7-day intake of NZBC extract (study two). Participants for both studies were different. In study one, NZBC extract enhanced isometric force steadiness during the 120 s contraction (placebo: 6.58 ± 2.24%, NZBC extract: 6.05 ± 2.24%, p = 0.003), with differences in the third (60-89 s) and fourth quartile (90-120 s) of the contraction. In study two, isometric force steadiness was not changed following 1 and 4 days but was enhanced following 7-day intake of NZBC extract in comparison to control. In study two, the enhanced isometric force steadiness following 7-day intake did occur in the second (30-59 s), third (60-89 s) and fourth (90-120 s) quartiles. Daily supplementation of anthocyanin-rich NZBC extract can enhance force steadiness of the quadriceps femoris muscle during a sustained submaximal isometric contraction. Our observations may have implications for human tasks that require postural stability.

Effect of Intake Duration of Anthocyanin-Rich New Zealand Blackcurrant Extract on Cardiovascular Responses and Femoral Artery Diameter during Sustained Submaximal Isometric Contraction

Seven-day intake of anthocyanins from New Zealand blackcurrant (NZBC) extract increased cardiac output and femoral artery diameter during a sustained submaximal isometric contraction. It is not known if there are intake duration effects by NZBC extract on the isometric contraction-induced cardiovascular responses. In a repeated measures design, male participants (n = 19, age: 26 ± 4 years) performed a 120-second submaximal (30%) isometric contraction of the knee extensors at baseline and following 1, 4 and 7-days intake of 600 mg·day^-1 NZBC extract. During the 120-second submaximal isometric contraction, femoral artery diameter and cardiovascular responses were measured with ultrasound and beat-to-beat hemodynamic monitoring. Femoral artery was larger following 4-days (mean difference = 0.046 cm, 95% CI [0.012, 0.080], p = 0.005) and 7-days (mean difference = 0.078 cm, 95% CI [0.034, 0.123], p < 0.001) in comparison to baseline with no increase with 1-day intake. Systolic and diastolic blood pressure, heart rate and total peripheral resistance were not changed by NZBC extract at 1, 4 and 7-days intake. However, mean arterial pressure, stroke volume, cardiac output and total peripheral resistance were changed at time points during the isometric contraction following 7-days intake in comparison to 1-day intake of NZBC extract (p < 0.05). Alterations in femoral artery diameter and some cardiovascular responses during a submaximal sustained isometric contraction of the knee extensors are affected by the intake duration of New Zealand blackcurrant extract, with no effects by 1-day intake. Our observations suggest that the bioavailability of blackcurrant anthocyanins and anthocyanin-derived metabolites is required for days to alter the mechanisms for isometric-contraction induced cardiovascular responses.