Abstract
ground: Due to its high polyphenol content and purported capability to mitigate post-exercise muscle soreness and promote recovery, tart cherry (TC) supplementation has been proposed to enhance recovery and athletic performance. This study exam- ined the effects of powdered TC supplementation on various recovery and performance metrics following a repeated sprint exercise protocol in physically active young adults. Methods: 40 (18 M, 22 F) healthy, active participants (24.6±5.5 yrs, 171.5±11 cm, 71.7±14.5 kg, 24.2±3.1 kg·m −2 ) participated in this randomized, double-blind, placebo- controlled, parallel study design. Placebo (PLA) or powdered TC supplementation (500 mg/day) occurred for ten days: seven days prior to, day of, and two days follow- ing repeated sprints (15×30 m with 1 min rest between sprints). Performance was assessed via the countermovement jump, isometric mid-thigh pull, isokinetic knee exten- sion, and the Wingate anaerobic test.Recovery was evaluated using visual analog scales for soreness, recovery,
(PLA) or powdered TC supplementation (500 mg/day) occurred for ten days: seven days prior to, day of, and two days follow- ing repeated sprints (15×30 m with 1 min rest between sprints). Performance was assessed via the countermovement jump, isometric mid-thigh pull, isokinetic knee exten- sion, and the Wingate anaerobic test.Recovery was evaluated using visual analog scales for soreness, recovery, and readiness to train. Muscle damage was evaluated using creatine kinase. These measures were evaluated at baseline, and at 1 h, 24 h, and 48 h post-exercise. Results: Significant main effects of time were observed with recovery VAS (p< 0.001),readi- ness to train VAS (p< 0.001), and jump height (p= 0.014) experiencing similar reduc- tions, while soreness VAS (p< 0.001) and creatine kinase (p= 0.05) experienced similar increases in response to the repeated sprint protocol and supplementation.Across all measurements, no significant group×time differences were observed for jump height (PLA:−6.7±10.4% vs. TC:−11.0±17.9%,p= 0.608), peak propulsive force (PLA: 0.3±4.6% vs. TC: 2.2±7.4%,p= 0.194), knee extension peak torque at 180 ◦ /s (PLA: 10.5±73.5% vs. TC:−1.04±49.6%,p= 0.335), readiness to train VAS (PLA:−23.0±19.2% vs. TC:−14.7±20.2%,p= 0.401), soreness VAS (PLA: 250±323% vs. TC: 261±432%, p= 0.838), recovery VAS (PLA:−24.6±17.9% vs. TC:−8.2±40.5%,p= 0.251), and creatine kinase (PLA: 22.8±35.5% vs. TC: 90.4±225.6%,p= 0.31). Conclusions: A single bout of repeated sprints was responsible for significant reductions in jump height, peak propulsive force, peak torque, and perceived readiness, while perceived soreness, myoglobin, and creatine kinase were significantly increased. Ten days of TC supplementation did not impact any change beyond what was observed in PLA for markers of recovery, readiness, soreness, exercise performance, and markers of muscle damage. Nutrients2026,18, 443 https://doi.org/10.3390/nu18030443
Nutrients2026,18, 443 2 of 24 Keywords:tart cherry; dietary supplement; repeated sprint exercise; exercise performance 1. Introduction High volume repetition of intense anaerobic performance bouts is expressed across a multitude of athletic endeavors through several modes of gameplay. Ground-based athletic competition such as soccer, football, rugby, lacrosse, basketball, and tennis, impart high- energy demand consisting of high volumes of concentric, eccentric, and isometric muscle actions, which stress both the mechanical and metabolic systems [1,2]. Exercise-induced muscle damage (EIMD) commonly results from these extended duration, perhaps unfa- miliar, events where eccentric-focused mechanical stress is carried out at a high metabolic intensity [3–7]. EIMD typically diminishes subsequent athletic performance via symp- toms such as delayed-onset muscle soreness (DOMS), edema, compromised joint range of motion, impaired neuromuscular strength and power, and inflammation [3,7–9]. Acute bouts of strenuous athletic performance commonly replicated in the literature using a single large volume, high intensity anaerobic event facilitate EIMD, characterized by underlying mechanical muscle damage, oxidative damage, and inflammation [10–14]. Specifically, the repetitive load-induced stress results in muscular injury via ultrastructural disruptions [15–17] and the subsequent release of intramuscular proteins into systemic circulation [18,19] that ultimately kickstarts the muscular repair sequence of degeneration, inflammation, regeneration, and fibrosis [15,20]. EIMD following damaging exercise is a consequence of high nociceptor and mechanoreceptor sensitivity to the potent chemicals and by-products released during this muscular degeneration [3,9,21]. In conjunction with the damage-inducing inflammatory process, higher volumes of repetitive muscular stress may also overwhelm the capacity of the endogenous antioxidant system to balance free radical production [22,23]. Collectively, symptoms of EIMD alongside the underlying repair and recovery process will prolong return to peak performance, impairing subsequently planned training and competition. For various reasons, nutritional research over the last 10–15 years has demonstrated in- creased emphasis toward the study of phytochemical-containing fruits and other functional foods that seem to provide a beneficial anti-inflammatory and antioxidant effect [24,25]. Phenolic compounds, such as flavonoids and anthocyanins, may act to support endogenous antioxidant systems to expedite exercise recovery [22,26]. Of the wide variety of antioxidant and polyphenol-containing functional foods, tart cherry (TC) supplement formulations have received attention
creased emphasis toward the study of phytochemical-containing fruits and other functional foods that seem to provide a beneficial anti-inflammatory and antioxidant effect [24,25]. Phenolic compounds, such as flavonoids and anthocyanins, may act to support endogenous antioxidant systems to expedite exercise recovery [22,26]. Of the wide variety of antioxidant and polyphenol-containing functional foods, tart cherry (TC) supplement formulations have received attention within the clinical and sports science literature due to their high anthocyanin content [27], which has demonstrated consistent benefit as a naturally oc- curring intervention to aid improvement in health [28–30], inflammatory-related disease states [29,31,32], and sleep quality [33,34]. To this point, the initial clinical nutrition sup- port realized from TC supplementation spurred sport nutrition researchers to use juice, concentrate, gel, and powder formulations to support the performance of endogenous physiological systems in managing muscle damage, oxidative stress, and inflammation following challenging exercise scenarios. For example, TC supplementation surrounding various bouts of resistance-based exercise in college-aged recreationally active and trained males has demonstrated ex- pedited muscular force production recovery compared to placebo (PLA) [18,24,35,36] across multiple TC formulations, with less strength recovery impact in female [37] and non-resistance trained populations [38]. Irrespective of the formulation, subject sex, and training experience, short-term TC supplementation has shown limited or inconsistent effects on post-exercise muscle tenderness and swelling [11,24,36–38], joint range of motion https://doi.org/10.3390/nu18030443
Nutrients2026,18, 443 3 of 24 capacity [11,24,38], indices of muscle damage [11,18], neuromuscular power performance [36,37], and quadricep muscular activation [37] surrounding single joint open kinetic chain resistive movements such as knee extensions. While influence on ox- idative damage following these types of movements with TC appears incongruent, TC supplementation surrounding high-volume closed-kinetic chain movements has demon- strated some promise attenuating post-exercise muscular strength decrement [35], muscle tenderness, or perceptions of pain [35,39], while remaining inconclusive regarding damage and oxidative stress indices [35,39]. High-volume intermittent work, such as repeated sprint exercise, provides a more eco- logically valid model for evaluating TC supplementation under anaerobic, sport-relevant conditions. Unlike the inconsistency observed across the scientific literature involving different types of resistance exercise, short-term TC supplementation collectively demon- strates attenuated perceptions of post-exercise muscle soreness [4,40–42] and pain pressure threshold [4] while facilitating greater muscular force production [40–42] and measures of neuromuscular power [4,40–42] surrounding various iterations of repeated sprint-interval (RSI) challenges. With further consistency, the current literature examining repeated sprints exhibits the limited impact of TC supplementation after strenuous exercise on indices of muscle damage [4,40,41] and inflammation [4,41]. Despite growing interest, the TC literature remains limited by the exclusion of females, minimal insight into changes related to hormone status and inflammation, and inconsistent use of exercise protocols that offer limited translation to sporting activity. For these reasons, the primary aim of the current study was to determine if short-term (10 days) ingestion of a powdered TC formulation surrounding a bout of repeated sprints would impact recovery, circulating concentrations of anabolic and catabolic hormones, muscle damage, oxidative stress, and inflammation connected to recovery, muscle damage, and inflammation, percep- tion of subsequent performance readiness, and ensuing exercise performance in a larger pool of recreationally trained males and females. We hypothesized that recreationally active participants will be better prepared for successive bouts of physical performance via re- duced muscle soreness and damage when supplementing with a powdered TC formulation surrounding a demanding repeated sprint protocol. 2. Materials and Methods 2.1. Experimental Design The study utilized a randomized, double-blind, placebo-controlled, parallel group study design (Figure).
recreationally trained males and females. We hypothesized that recreationally active participants will be better prepared for successive bouts of physical performance via re- duced muscle soreness and damage when supplementing with a powdered TC formulation surrounding a demanding repeated sprint protocol. 2. Materials and Methods 2.1. Experimental Design The study utilized a randomized, double-blind, placebo-controlled, parallel group study design (Figure). Prior to data collection, potential participants reviewed the protocol and provided written informed consent via an IRB-approved consent form. Healthy male and female participants (n= 40) who regularly participated in recreational sports or high- intensity, multi-modal resistance-based exercise were included. Regular participation was defined as exercising at least four days per week, with a minimum of two days involving high-intensity exercise, for the past six months, as determined by the International Physical Activity Questionnaire. Participants complete four laboratory visits. Visit 1 involved initial screening, assessment of height, body mass, and body composition, and concluded with familiarization with the testing procedures. Once eligibility was confirmed, participants were randomized by biological sex and baseline fat-free mass to ingest either PLA (rice flour) or powdered tart cherries (ADSO Naturals, Bangalore, India). Participants consumed the supplements over a 10-day period, with doses 1–7 taken daily before returning to the lab for Visit 2. Dose 8 was taken on the morning of Visit 2, dose 9 on the morning of Visit 3, and dose 10 on the morning of Visit 4. Body mass, resting blood pressure, and resting heart rate were assessed during all visits. https://doi.org/10.3390/nu18030443
Nutrients2026,18, 443 4 of 24 Figure 1.Overview of research design. Visit 2 served as the baseline testing session and the start of the post-exercise recovery period. During Visit 2, a venous blood sample was taken to measure baseline markers of health, muscle damage, oxidative stress, inflammation, testosterone, and cortisol. Partici- pants completed visual analog scales to provide perceived levels of recovery, soreness, and readiness to exercise before completing a standardized warm-up. Performance testing was completed in a fixed order: (1) countermovement jumps, (2) isometric voluntary contrac- tions, (3) isokinetic dynamometry using the knee extensors, and (4) a Wingate anaerobic test. This sequence was identical for all participants and across all applicable testing timepoints. Standardized rest periods were provided between performance assessments to minimize fatigue carryover. Participants rested for approximately three minutes between each assess- ment. Baseline assessments were completed prior to the initiation of the repeated sprint protocol. The repeated sprint protocol consisted of 15×30 m maximal sprints performed on an environmentally controlled indoor running track, with standardized rest periods between sprints, as described below. Participants remained in the laboratory for one hour after completion of the sprint protocol to provide an additional blood sample and complete all assessments. Blood sample collection and performance assessments were then repeated during subsequent laboratory visits that occurred 24 h (Visit 3) and 48 h (Visit 4) after completion of the sprint protocol. As such and for clarity throughout the manuscript, data collection timepoints are referred to as Baseline, 1 h Post, 24 h Post, and 48 h Post, which respectively correspond with Visits 2, 3, 4, and 5 as described herein. Each participant completed all laboratory visits at the same time of day (±1 h), with all study visits commencing between 0600 and 1000 h. Prior to each study visit, participants observed an overnight fast for 8–10 h with no caffeine or nicotine for 12 h prior. During laboratory visits, participants were permitted to consume water ad libitum to maintain hydration; however, no calorie containing beverages or food were allowed during the exercise testing repeated sprint exercise bout or rest periods. No vigorous
1000 h. Prior to each study visit, participants observed an overnight fast for 8–10 h with no caffeine or nicotine for 12 h prior. During laboratory visits, participants were permitted to consume water ad libitum to maintain hydration; however, no calorie containing beverages or food were allowed during the exercise testing repeated sprint exercise bout or rest periods. No vigorous exercise was permitted 48 h before, and only light physical activity was permitted 24 h before Visit 2. No exercise was permitted between Visits 2 and 4. Participants were further instructed to refrain from using percussive or compression devices, hot or cold showers or baths, foam rolling, or consuming any prescription or over-the-counter anti-inflammatory medications throughout the study to prevent interference with recovery and performance outcomes. The study was approved by the Institutional Review Board of Lindenwood University (IRB-23-11, approval date: https://doi.org/10.3390/nu18030443
Nutrients2026,18, 443 5 of 24 27 January 2023) and was conducted in accordance with the Declaration of Helsinki. The study was prospectively registered at ClinicalTrials.gov (identifier: NCT06122038). 2.2. Study Participants Healthy, recreationally active males (n= 18) and females (n= 22) completed the entire study protocol and were included in the final analyses. To be eligible, participants were required to be engaged in at least four days of exercise per week, with a minimum of two high-intensity exercise sessions weekly for at least six months prior to the study. High-intensity exercise was defined as reporting participation in at least two days per week of vigorous-intensity physical activity as indicated on the International Physical Activity Questionnaire—Short Form (IPAQ-SF). Participants were required to be between 20 and 35 years of age and have a body mass index (BMI) of 18.0–30.0 kg/m 2 . Individuals with a BMI greater than 30.0 kg/m2 were accepted if their body fat percentage was less than 27.5% for males and 32.5% for females. All participants were free from known cardiovascular, metabolic, renal, hepatic, or neurological disease, and were non-smokers not currently using any medications or sup- plements known to affect inflammation, recovery, or performance. Participants were not pregnant, lactating, or following any weight-loss protocols in the 30 days prior to enroll- ment. A detailed health history questionnaire was used to screen exclusion criteria, and participants were excluded if any condition was present that could compromise safety or study outcomes. Participants were instructed to discontinue all ergogenic nutritional supplements (e.g., creatine monohydrate,β-alanine) and supplements known or purported to impact muscle repair or recovery (e.g., antioxidants, creatine, HMB, curcumin, turmeric, Vitamin D, TC) for 30 days prior to participation. 2.3. Anthropometric, Hemodynamic, and Body Composition Assessments During Visit 1, participants’ height was measured without shoes to the nearest 0.5 cm using a wall-mounted stadiometer (HR-200, Tanita Corp, Inc., Tokyo, Japan). Body mass was recorded to the nearest 0.1 kg during each study visit with a self-calibrating digital scale (Tanita BWB-627A, Tokyo, Japan). Resting heart rate and blood pressure were measured during each visit using an automated blood pressure cuff (3
height was measured without shoes to the nearest 0.5 cm using a wall-mounted stadiometer (HR-200, Tanita Corp, Inc., Tokyo, Japan). Body mass was recorded to the nearest 0.1 kg during each study visit with a self-calibrating digital scale (Tanita BWB-627A, Tokyo, Japan). Resting heart rate and blood pressure were measured during each visit using an automated blood pressure cuff (3 Series ® Upper Arm Blood Pressure Monitor, OMRON Healthcare, Kyoto, Japan) after a 5 min seated period. Body composition, including body-fat percentage, skeletal muscle mass, and total body water, was assessed using a bioelectrical impedance analyzer (BIA; InBody 570, InBody USA, Cerritos, CA, USA). Participants removed their socks, emptied pockets, and removed heavy clothing or accessories before each scan, and wiped their hands and feet using wipes provided by the manufacturer (Inbody USA, Cerritos, CA, USA). 2.4. Supplementation Following the initial familiarization visit, participants consumed their assigned supplement daily for a 10-day period. Doses 1 through 7 were taken daily leading up to Visit 2, which coincided with the repeated sprint protocol. Dose 8 was con- sumed on the morning of Visit 2, dose 9 on the morning of Visit 3, and dose 10 on the morning of Visit 4. Participants were instructed to take one capsule of their assigned supplement at the same time each day with their first meal, ensuring to include fats, proteins, and carbohydrates in the meal. The experimental supplement consisted of 500 mg of powdered tart cherries (TCs) (ADSO Naturals, Bangalore, India) in capsule form. The PLA group received rice flour. Total phenolic content of the powdered TC was 1.16%w/w,resulting in each 500 mg delivering a phenolic dose of 5.8 milligrams. Each PLA dose delivered approximately 0.4 g carbohydrates and 7.7 kJ for a total anticipated delivery of 4 g of carbohydrate and 76.6 kJ. Randomization and allocation concealment https://doi.org/10.3390/nu18030443
Nutrients2026,18, 443 6 of 24 were maintained throughout the study. Investigators and participants remained blinded to treatment assignment until all data collection and primary analyses were completed. To ensure integrity of blinding, all capsules were non-transparent, the same color, size, and smell. To assess compliance, participants completed a daily diary documenting their supplement intake and any adverse events. 2.5. Repeated Sprint Exercise Bout Participants completed the repeated sprint exercise bout following the methods of Howatson and Malik [43,44] on an environmentally controlled indoor running track marked with cones and lighted timing gates (RM-510, Arena Gear, McKinney, TX, USA). A 30 m sprint section was marked off along with a 10 m deceleration zone. Participants completed three practice sprints at 60%, 80%, and 100% perceived speed with one-minute rest between sprints. After practice sprints were completed, a three-minute break was observed. Partici- pants then stood 12 inches from the start line to avoid premature triggering of the timing system and completed 15 separate 30 m sprints with one minute rest between each sprint. All efforts were completed using a maximal effort, and participants came to a complete stop within the 10 m deceleration zone. Strong verbal encouragement was provided throughout each sprint. Time to complete each sprint was recorded. 2.6. Performance Testing 2.6.1. Countermovement Jumps Countermovement jumps (CMJs) were used to assess lower-body power. Testing was conducted using a pair of force plates (Hawkin Dynamics, Westbrook, ME, USA). Participants stood with one foot in the middle of each force plate with their feet shoulder- width apart while keeping their hands on their hips throughout the movement to eliminate the influence of arm swing. All participants stood in the same direction and general orientation for all jumps in the study protocol. They initiated the movement by bending at the knees and hips to a self-selected depth before jumping as high as possible. Each participant performed three maximal effort jumps with 60 s of rest between attempts. The force plates captured ground reaction forces in real-time, which were analyzed in real-time. The highest jump height and peak propulsive force output was highlighted by
initiated the movement by bending at the knees and hips to a self-selected depth before jumping as high as possible. Each participant performed three maximal effort jumps with 60 s of rest between attempts. The force plates captured ground reaction forces in real-time, which were analyzed in real-time. The highest jump height and peak propulsive force output was highlighted by the software and used for statistical analysis. CMJ testing was performed at baseline, immediately post-exercise, and at 24 and 48 h post-exercise to assess recovery dynamics. A standardized rest interval of three minutes was provided between performance testing protocols. 2.6.2. Isometric Mid-Thigh Pull The isometric mid-thigh pull (IMTP) was conducted to assess maximal isometric strength according to previously described procedures [45]. Participants performed the IMTP using a fixed bar in a custom rig attached to dual force plates (PASPORT Force Platform, PASCO Scientific, Roseville, CA, USA). Participants were instructed to stand on the force plates in the same direction with one foot in the center of each force plate and position the bar at mid-thigh height while maintaining a knee angle of approximately 125 ◦ and a torso angle of 145 ◦ , with a neutral spine and hips. After positioning, participants were instructed to pull the bar upward as hard and as fast as possible for five seconds, aiming to generate maximal force against the immovable bar. Verbal encouragement was provided throughout the test to maximize effort. Three attempts were performed at each timepoint, with one minute of rest between attempts. Peak force was recorded during each trial, with the highest value being used for analysis. IMTP testing was conducted at baseline, immediately post-exercise, and at 24 and 48 h post-exercise. https://doi.org/10.3390/nu18030443
Description
The study investigates tart cherry supplementation's impact on recovery after repeated sprint exercise.